diff --git a/cmd/bitflags/endtoend_test.go b/cmd/bitflags/endtoend_test.go
new file mode 100644
index 0000000..d0dcd2d
--- /dev/null
+++ b/cmd/bitflags/endtoend_test.go
@@ -0,0 +1,163 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+	"sync"
+	"testing"
+
+	"github.com/flier/go-bitflags/internal/testenv"
+)
+
+// This file contains a test that compiles and runs each program in testdata
+// after generating the string method for its type. The rule is that for testdata/x.go
+// we run `bitflags -type X` and then compile and run the program. The resulting
+// binary panics if the String method for X is not correct, including for error cases.
+
+func TestMain(m *testing.M) {
+	if os.Getenv("BITFLAGS_TEST_IS_BITFLAGS") != "" {
+		main()
+		os.Exit(0)
+	}
+
+	// Inform subprocesses that they should run the `cmd/bitflags` main instead of
+	// running tests. It's a close approximation to building and running the real
+	// command, and much less complicated and expensive to build and clean up.
+	os.Setenv("BITFLAGS_TEST_IS_BITFLAGS", "1")
+
+	flag.Parse()
+	if testing.Verbose() {
+		os.Setenv("GOPACKAGESDEBUG", "true")
+	}
+
+	os.Exit(m.Run())
+}
+
+func TestEndToEnd(t *testing.T) {
+	testenv.NeedsTool(t, "go")
+
+	executable := executablePath(t)
+	// Read the testdata directory.
+	fd, err := os.Open("testdata")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer fd.Close()
+	names, err := fd.Readdirnames(-1)
+	if err != nil {
+		t.Fatalf("Readdirnames: %s", err)
+	}
+	// Generate, compile, and run the test programs.
+	for _, name := range names {
+		if name == "typeparams" {
+			// ignore the directory containing the tests with type params
+			continue
+		}
+		if !strings.HasSuffix(name, ".go") {
+			t.Errorf("%s is not a Go file", name)
+			continue
+		}
+		if strings.HasPrefix(name, "tag_") || strings.HasPrefix(name, "vary_") {
+			// This file is used for tag processing in TestTags or TestConstValueChange, below.
+			continue
+		}
+		t.Run(name, func(t *testing.T) {
+			if name == "cgo.go" {
+				testenv.NeedsTool(t, "cgo")
+			}
+			bitflagsCompileAndRun(t, t.TempDir(), executable, typeName(name), name)
+		})
+	}
+}
+
+var exe struct {
+	path string
+	err  error
+	once sync.Once
+}
+
+func executablePath(t *testing.T) string {
+	testenv.NeedsExec(t)
+
+	exe.once.Do(func() {
+		exe.path, exe.err = os.Executable()
+	})
+	if exe.err != nil {
+		t.Fatal(exe.err)
+	}
+	return exe.path
+}
+
+// a type name for stringer. use the last component of the file name with the .go
+func typeName(fname string) string {
+	// file names are known to be ascii and end .go
+	base := path.Base(fname)
+	return fmt.Sprintf("%c%s", base[0]+'A'-'a', base[1:len(base)-len(".go")])
+}
+
+// stringerCompileAndRun runs stringer for the named file and compiles and
+// runs the target binary in directory dir. That binary will panic if the String method is incorrect.
+func bitflagsCompileAndRun(t *testing.T, dir, executable, typeName, fileName string) {
+	t.Logf("run: %s %s\n", fileName, typeName)
+	source := filepath.Join(dir, path.Base(fileName))
+	err := copyFile(source, filepath.Join("testdata", fileName))
+	if err != nil {
+		t.Fatalf("copying file to temporary directory: %s", err)
+	}
+	stringSource := filepath.Join(dir, typeName+"_string.go")
+	// Run stringer in temporary directory.
+	err = run(t, executable, "-type", typeName, "-output", stringSource, source)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Run the binary in the temporary directory.
+	err = run(t, "go", "run", stringSource, source)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+// copyFile copies the from file to the to file.
+func copyFile(to, from string) error {
+	toFd, err := os.Create(to)
+	if err != nil {
+		return err
+	}
+	defer toFd.Close()
+	fromFd, err := os.Open(from)
+	if err != nil {
+		return err
+	}
+	defer fromFd.Close()
+	_, err = io.Copy(toFd, fromFd)
+	return err
+}
+
+// run runs a single command and returns an error if it does not succeed.
+// os/exec should have this function, to be honest.
+func run(t testing.TB, name string, arg ...string) error {
+	t.Helper()
+	return runInDir(t, ".", name, arg...)
+}
+
+// runInDir runs a single command in directory dir and returns an error if
+// it does not succeed.
+func runInDir(t testing.TB, dir, name string, arg ...string) error {
+	t.Helper()
+	cmd := testenv.Command(t, name, arg...)
+	cmd.Dir = dir
+	cmd.Env = append(os.Environ(), "GO111MODULE=auto")
+	out, err := cmd.CombinedOutput()
+	if len(out) > 0 {
+		t.Logf("%s", out)
+	}
+	if err != nil {
+		return fmt.Errorf("%v: %v", cmd, err)
+	}
+	return nil
+}
diff --git a/cmd/bitflags/main.go b/cmd/bitflags/main.go
index b07d866..959b748 100644
--- a/cmd/bitflags/main.go
+++ b/cmd/bitflags/main.go
@@ -1,7 +1,9 @@
 // Bitflags is a tool to automate the creation of methods that satisfy the fmt.Stringer
 // interface. Given the name of a (signed or unsigned) integer type T that has constants
 // defined, bitflags will create a new self-contained Go source file implementing
+//
 //	func (t T) String() string
+//
 // The file is created in the same package and directory as the package that defines T.
 // It has helpful defaults designed for use with go generate.
 //
@@ -95,25 +97,14 @@ type config struct {
 }
 
 const (
-	prog    = "bitflags"
-	author  = "Flier Lu <flier.lu@gmail.com>"
-	repo    = "https://github.com/flier/go-bitflags"
-	summary = `
-    {{ .Name }} [flags] -type T [directory]
-    {{ .Name }} [flags] -type T files... # Must be a single package
-
-For more information, see:
-
-    https://github.com/flier/go-bitflags/cmd/bitflags`
+	prog   = "bitflags"
+	author = "Flier Lu <flier.lu@gmail.com>"
+	repo   = "https://github.com/flier/go-bitflags"
 )
 
 func main() {
-	var b strings.Builder
-	template.Must(template.New("summary").Parse(summary)).Execute(&b, map[string]interface{}{"Name": prog})
-	summary := strings.TrimRight(b.String(), "\n")
-
 	c := config{}
-	opts.New(&c).Author(author).Summary(summary).Repo(repo).Parse()
+	opts.New(&c).Summary(summary()).Repo(repo).Author(author).Parse()
 
 	g := gen.New(c.TrimPrefix, c.LineComment)
 
@@ -165,6 +156,15 @@ func main() {
 	}
 }
 
+func summary() string {
+	var b strings.Builder
+	template.Must(template.New("summary").Parse(`
+    {{ .Name }} [flags] -type T [directory]
+    {{ .Name }} [flags] -type T files... # Must be a single package
+`)).Execute(&b, map[string]interface{}{"Name": prog})
+	return strings.Trim(b.String(), "\n")
+}
+
 func isDirectory(name string) bool {
 	info, err := os.Stat(name)
 	if err != nil {
diff --git a/go.mod b/go.mod
index 4de7c02..6f1055e 100644
--- a/go.mod
+++ b/go.mod
@@ -1,12 +1,15 @@
 module github.com/flier/go-bitflags
 
-go 1.16
+go 1.18
+
+require (
+	github.com/jpillora/opts v1.2.0
+	golang.org/x/mod v0.15.0
+	golang.org/x/tools v0.18.0
+)
 
 require (
 	github.com/hashicorp/errwrap v1.1.0 // indirect
 	github.com/hashicorp/go-multierror v1.1.1 // indirect
-	github.com/jpillora/opts v1.2.0
 	github.com/posener/complete v1.2.3 // indirect
-	golang.org/x/sys v0.1.0 // indirect
-	golang.org/x/tools v0.1.8
 )
diff --git a/go.sum b/go.sum
index a22e89a..c3c50d5 100644
--- a/go.sum
+++ b/go.sum
@@ -16,35 +16,11 @@ github.com/posener/complete v1.2.3/go.mod h1:WZIdtGGp+qx0sLrYKtIRAruyNpv6hFCicSg
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-github.com/yuin/goldmark v1.4.1/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
-golang.org/x/mod v0.5.1 h1:OJxoQ/rynoF0dcCdI7cLPktw/hR2cueqYfjm43oqK38=
-golang.org/x/mod v0.5.1/go.mod h1:5OXOZSfqPIIbmVBIIKWRFfZjPR0E5r58TLhUjH0a2Ro=
-golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/net v0.0.0-20211015210444-4f30a5c0130f/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
-golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20211019181941-9d821ace8654/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.1.0 h1:kunALQeHf1/185U1i0GOB/fy1IPRDDpuoOOqRReG57U=
-golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/tools v0.1.8 h1:P1HhGGuLW4aAclzjtmJdf0mJOjVUZUzOTqkAkWL+l6w=
-golang.org/x/tools v0.1.8/go.mod h1:nABZi5QlRsZVlzPpHl034qft6wpY4eDcsTt5AaioBiU=
-golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
-golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/mod v0.15.0 h1:SernR4v+D55NyBH2QiEQrlBAnj1ECL6AGrA5+dPaMY8=
+golang.org/x/mod v0.15.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/sync v0.6.0 h1:5BMeUDZ7vkXGfEr1x9B4bRcTH4lpkTkpdh0T/J+qjbQ=
+golang.org/x/tools v0.18.0 h1:k8NLag8AGHnn+PHbl7g43CtqZAwG60vZkLqgyZgIHgQ=
+golang.org/x/tools v0.18.0/go.mod h1:GL7B4CwcLLeo59yx/9UWWuNOW1n3VZ4f5axWfML7Lcg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
diff --git a/internal/goroot/importcfg.go b/internal/goroot/importcfg.go
new file mode 100644
index 0000000..f1cd28e
--- /dev/null
+++ b/internal/goroot/importcfg.go
@@ -0,0 +1,71 @@
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package goroot is a copy of package internal/goroot
+// in the main GO repot. It provides a utility to produce
+// an importcfg and import path to package file map mapping
+// standard library packages to the locations of their export
+// data files.
+package goroot
+
+import (
+	"bytes"
+	"fmt"
+	"os/exec"
+	"strings"
+	"sync"
+)
+
+// Importcfg returns an importcfg file to be passed to the
+// Go compiler that contains the cached paths for the .a files for the
+// standard library.
+func Importcfg() (string, error) {
+	var icfg bytes.Buffer
+
+	m, err := PkgfileMap()
+	if err != nil {
+		return "", err
+	}
+	fmt.Fprintf(&icfg, "# import config")
+	for importPath, export := range m {
+		fmt.Fprintf(&icfg, "\npackagefile %s=%s", importPath, export)
+	}
+	s := icfg.String()
+	return s, nil
+}
+
+var (
+	stdlibPkgfileMap map[string]string
+	stdlibPkgfileErr error
+	once             sync.Once
+)
+
+// PkgfileMap returns a map of package paths to the location on disk
+// of the .a file for the package.
+// The caller must not modify the map.
+func PkgfileMap() (map[string]string, error) {
+	once.Do(func() {
+		m := make(map[string]string)
+		output, err := exec.Command("go", "list", "-export", "-e", "-f", "{{.ImportPath}} {{.Export}}", "std", "cmd").Output()
+		if err != nil {
+			stdlibPkgfileErr = err
+		}
+		for _, line := range strings.Split(string(output), "\n") {
+			if line == "" {
+				continue
+			}
+			sp := strings.SplitN(line, " ", 2)
+			if len(sp) != 2 {
+				err = fmt.Errorf("determining pkgfile map: invalid line in go list output: %q", line)
+				return
+			}
+			importPath, export := sp[0], sp[1]
+			if export != "" {
+				m[importPath] = export
+			}
+		}
+		stdlibPkgfileMap = m
+	})
+	return stdlibPkgfileMap, stdlibPkgfileErr
+}
diff --git a/internal/testenv/exec.go b/internal/testenv/exec.go
new file mode 100644
index 0000000..3b0cb6f
--- /dev/null
+++ b/internal/testenv/exec.go
@@ -0,0 +1,192 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package testenv
+
+import (
+	"context"
+	"flag"
+	"os"
+	"os/exec"
+	"reflect"
+	"runtime"
+	"strconv"
+	"sync"
+	"testing"
+	"time"
+)
+
+// HasExec reports whether the current system can start new processes
+// using os.StartProcess or (more commonly) exec.Command.
+func HasExec() bool {
+	switch runtime.GOOS {
+	case "aix",
+		"android",
+		"darwin",
+		"dragonfly",
+		"freebsd",
+		"illumos",
+		"linux",
+		"netbsd",
+		"openbsd",
+		"plan9",
+		"solaris",
+		"windows":
+		// Known OS that isn't ios or wasm; assume that exec works.
+		return true
+
+	case "ios", "js", "wasip1":
+		// ios has an exec syscall but on real iOS devices it might return a
+		// permission error. In an emulated environment (such as a Corellium host)
+		// it might succeed, so try it and find out.
+		//
+		// As of 2023-04-19 wasip1 and js don't have exec syscalls at all, but we
+		// may as well use the same path so that this branch can be tested without
+		// an ios environment.
+		fallthrough
+
+	default:
+		tryExecOnce.Do(func() {
+			exe, err := os.Executable()
+			if err != nil {
+				return
+			}
+			if flag.Lookup("test.list") == nil {
+				// We found the executable, but we don't know how to run it in a way
+				// that should succeed without side-effects. Just forget it.
+				return
+			}
+			// We know that a test executable exists and can run, because we're
+			// running it now. Use it to check for overall exec support, but be sure
+			// to remove any environment variables that might trigger non-default
+			// behavior in a custom TestMain.
+			cmd := exec.Command(exe, "-test.list=^$")
+			cmd.Env = []string{}
+			if err := cmd.Run(); err == nil {
+				tryExecOk = true
+			}
+		})
+		return tryExecOk
+	}
+}
+
+var (
+	tryExecOnce sync.Once
+	tryExecOk   bool
+)
+
+// NeedsExec checks that the current system can start new processes
+// using os.StartProcess or (more commonly) exec.Command.
+// If not, NeedsExec calls t.Skip with an explanation.
+func NeedsExec(t testing.TB) {
+	if !HasExec() {
+		t.Skipf("skipping test: cannot exec subprocess on %s/%s", runtime.GOOS, runtime.GOARCH)
+	}
+}
+
+// CommandContext is like exec.CommandContext, but:
+//   - skips t if the platform does not support os/exec,
+//   - if supported, sends SIGQUIT instead of SIGKILL in its Cancel function
+//   - if the test has a deadline, adds a Context timeout and (if supported) WaitDelay
+//     for an arbitrary grace period before the test's deadline expires,
+//   - if Cmd has the Cancel field, fails the test if the command is canceled
+//     due to the test's deadline, and
+//   - sets a Cleanup function that verifies that the test did not leak a subprocess.
+func CommandContext(t testing.TB, ctx context.Context, name string, args ...string) *exec.Cmd {
+	t.Helper()
+	NeedsExec(t)
+
+	var (
+		cancelCtx   context.CancelFunc
+		gracePeriod time.Duration // unlimited unless the test has a deadline (to allow for interactive debugging)
+	)
+
+	if td, ok := Deadline(t); ok {
+		// Start with a minimum grace period, just long enough to consume the
+		// output of a reasonable program after it terminates.
+		gracePeriod = 100 * time.Millisecond
+		if s := os.Getenv("GO_TEST_TIMEOUT_SCALE"); s != "" {
+			scale, err := strconv.Atoi(s)
+			if err != nil {
+				t.Fatalf("invalid GO_TEST_TIMEOUT_SCALE: %v", err)
+			}
+			gracePeriod *= time.Duration(scale)
+		}
+
+		// If time allows, increase the termination grace period to 5% of the
+		// test's remaining time.
+		testTimeout := time.Until(td)
+		if gp := testTimeout / 20; gp > gracePeriod {
+			gracePeriod = gp
+		}
+
+		// When we run commands that execute subprocesses, we want to reserve two
+		// grace periods to clean up: one for the delay between the first
+		// termination signal being sent (via the Cancel callback when the Context
+		// expires) and the process being forcibly terminated (via the WaitDelay
+		// field), and a second one for the delay becween the process being
+		// terminated and and the test logging its output for debugging.
+		//
+		// (We want to ensure that the test process itself has enough time to
+		// log the output before it is also terminated.)
+		cmdTimeout := testTimeout - 2*gracePeriod
+
+		if cd, ok := ctx.Deadline(); !ok || time.Until(cd) > cmdTimeout {
+			// Either ctx doesn't have a deadline, or its deadline would expire
+			// after (or too close before) the test has already timed out.
+			// Add a shorter timeout so that the test will produce useful output.
+			ctx, cancelCtx = context.WithTimeout(ctx, cmdTimeout)
+		}
+	}
+
+	cmd := exec.CommandContext(ctx, name, args...)
+
+	// Use reflection to set the Cancel and WaitDelay fields, if present.
+	// TODO(bcmills): When we no longer support Go versions below 1.20,
+	// remove the use of reflect and assume that the fields are always present.
+	rc := reflect.ValueOf(cmd).Elem()
+
+	if rCancel := rc.FieldByName("Cancel"); rCancel.IsValid() {
+		rCancel.Set(reflect.ValueOf(func() error {
+			if cancelCtx != nil && ctx.Err() == context.DeadlineExceeded {
+				// The command timed out due to running too close to the test's deadline
+				// (because we specifically set a shorter Context deadline for that
+				// above). There is no way the test did that intentionally — it's too
+				// close to the wire! — so mark it as a test failure. That way, if the
+				// test expects the command to fail for some other reason, it doesn't
+				// have to distinguish between that reason and a timeout.
+				t.Errorf("test timed out while running command: %v", cmd)
+			} else {
+				// The command is being terminated due to ctx being canceled, but
+				// apparently not due to an explicit test deadline that we added.
+				// Log that information in case it is useful for diagnosing a failure,
+				// but don't actually fail the test because of it.
+				t.Logf("%v: terminating command: %v", ctx.Err(), cmd)
+			}
+			return cmd.Process.Signal(Sigquit)
+		}))
+	}
+
+	if rWaitDelay := rc.FieldByName("WaitDelay"); rWaitDelay.IsValid() {
+		rWaitDelay.Set(reflect.ValueOf(gracePeriod))
+	}
+
+	t.Cleanup(func() {
+		if cancelCtx != nil {
+			cancelCtx()
+		}
+		if cmd.Process != nil && cmd.ProcessState == nil {
+			t.Errorf("command was started, but test did not wait for it to complete: %v", cmd)
+		}
+	})
+
+	return cmd
+}
+
+// Command is like exec.Command, but applies the same changes as
+// testenv.CommandContext (with a default Context).
+func Command(t testing.TB, name string, args ...string) *exec.Cmd {
+	t.Helper()
+	return CommandContext(t, context.Background(), name, args...)
+}
diff --git a/internal/testenv/testenv.go b/internal/testenv/testenv.go
new file mode 100644
index 0000000..0e9ee79
--- /dev/null
+++ b/internal/testenv/testenv.go
@@ -0,0 +1,490 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package testenv contains helper functions for skipping tests
+// based on which tools are present in the environment.
+package testenv
+
+import (
+	"bytes"
+	"fmt"
+	"go/build"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"runtime/debug"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"golang.org/x/mod/modfile"
+
+	"github.com/flier/go-bitflags/internal/goroot"
+)
+
+// packageMainIsDevel reports whether the module containing package main
+// is a development version (if module information is available).
+func packageMainIsDevel() bool {
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		// Most test binaries currently lack build info, but this should become more
+		// permissive once https://golang.org/issue/33976 is fixed.
+		return true
+	}
+
+	// Note: info.Main.Version describes the version of the module containing
+	// package main, not the version of “the main module”.
+	// See https://golang.org/issue/33975.
+	return info.Main.Version == "(devel)"
+}
+
+var checkGoBuild struct {
+	once sync.Once
+	err  error
+}
+
+func hasTool(tool string) error {
+	if tool == "cgo" {
+		enabled, err := cgoEnabled(false)
+		if err != nil {
+			return fmt.Errorf("checking cgo: %v", err)
+		}
+		if !enabled {
+			return fmt.Errorf("cgo not enabled")
+		}
+		return nil
+	}
+
+	_, err := exec.LookPath(tool)
+	if err != nil {
+		return err
+	}
+
+	switch tool {
+	case "patch":
+		// check that the patch tools supports the -o argument
+		temp, err := os.CreateTemp("", "patch-test")
+		if err != nil {
+			return err
+		}
+		temp.Close()
+		defer os.Remove(temp.Name())
+		cmd := exec.Command(tool, "-o", temp.Name())
+		if err := cmd.Run(); err != nil {
+			return err
+		}
+
+	case "go":
+		checkGoBuild.once.Do(func() {
+			if runtime.GOROOT() != "" {
+				// Ensure that the 'go' command found by exec.LookPath is from the correct
+				// GOROOT. Otherwise, 'some/path/go test ./...' will test against some
+				// version of the 'go' binary other than 'some/path/go', which is almost
+				// certainly not what the user intended.
+				out, err := exec.Command(tool, "env", "GOROOT").Output()
+				if err != nil {
+					if exit, ok := err.(*exec.ExitError); ok && len(exit.Stderr) > 0 {
+						err = fmt.Errorf("%w\nstderr:\n%s)", err, exit.Stderr)
+					}
+					checkGoBuild.err = err
+					return
+				}
+				GOROOT := strings.TrimSpace(string(out))
+				if GOROOT != runtime.GOROOT() {
+					checkGoBuild.err = fmt.Errorf("'go env GOROOT' does not match runtime.GOROOT:\n\tgo env: %s\n\tGOROOT: %s", GOROOT, runtime.GOROOT())
+					return
+				}
+			}
+
+			dir, err := os.MkdirTemp("", "testenv-*")
+			if err != nil {
+				checkGoBuild.err = err
+				return
+			}
+			defer os.RemoveAll(dir)
+
+			mainGo := filepath.Join(dir, "main.go")
+			if err := os.WriteFile(mainGo, []byte("package main\nfunc main() {}\n"), 0644); err != nil {
+				checkGoBuild.err = err
+				return
+			}
+			cmd := exec.Command("go", "build", "-o", os.DevNull, mainGo)
+			cmd.Dir = dir
+			if out, err := cmd.CombinedOutput(); err != nil {
+				if len(out) > 0 {
+					checkGoBuild.err = fmt.Errorf("%v: %v\n%s", cmd, err, out)
+				} else {
+					checkGoBuild.err = fmt.Errorf("%v: %v", cmd, err)
+				}
+			}
+		})
+		if checkGoBuild.err != nil {
+			return checkGoBuild.err
+		}
+
+	case "diff":
+		// Check that diff is the GNU version, needed for the -u argument and
+		// to report missing newlines at the end of files.
+		out, err := exec.Command(tool, "-version").Output()
+		if err != nil {
+			return err
+		}
+		if !bytes.Contains(out, []byte("GNU diffutils")) {
+			return fmt.Errorf("diff is not the GNU version")
+		}
+	}
+
+	return nil
+}
+
+func cgoEnabled(bypassEnvironment bool) (bool, error) {
+	cmd := exec.Command("go", "env", "CGO_ENABLED")
+	if bypassEnvironment {
+		cmd.Env = append(append([]string(nil), os.Environ()...), "CGO_ENABLED=")
+	}
+	out, err := cmd.Output()
+	if err != nil {
+		if exit, ok := err.(*exec.ExitError); ok && len(exit.Stderr) > 0 {
+			err = fmt.Errorf("%w\nstderr:\n%s", err, exit.Stderr)
+		}
+		return false, err
+	}
+	enabled := strings.TrimSpace(string(out))
+	return enabled == "1", nil
+}
+
+func allowMissingTool(tool string) bool {
+	switch runtime.GOOS {
+	case "aix", "darwin", "dragonfly", "freebsd", "illumos", "linux", "netbsd", "openbsd", "plan9", "solaris", "windows":
+		// Known non-mobile OS. Expect a reasonably complete environment.
+	default:
+		return true
+	}
+
+	switch tool {
+	case "cgo":
+		if strings.HasSuffix(os.Getenv("GO_BUILDER_NAME"), "-nocgo") {
+			// Explicitly disabled on -nocgo builders.
+			return true
+		}
+		if enabled, err := cgoEnabled(true); err == nil && !enabled {
+			// No platform support.
+			return true
+		}
+	case "go":
+		if os.Getenv("GO_BUILDER_NAME") == "illumos-amd64-joyent" {
+			// Work around a misconfigured builder (see https://golang.org/issue/33950).
+			return true
+		}
+	case "diff":
+		if os.Getenv("GO_BUILDER_NAME") != "" {
+			return true
+		}
+	case "patch":
+		if os.Getenv("GO_BUILDER_NAME") != "" {
+			return true
+		}
+	}
+
+	// If a developer is actively working on this test, we expect them to have all
+	// of its dependencies installed. However, if it's just a dependency of some
+	// other module (for example, being run via 'go test all'), we should be more
+	// tolerant of unusual environments.
+	return !packageMainIsDevel()
+}
+
+// NeedsTool skips t if the named tool is not present in the path.
+// As a special case, "cgo" means "go" is present and can compile cgo programs.
+func NeedsTool(t testing.TB, tool string) {
+	err := hasTool(tool)
+	if err == nil {
+		return
+	}
+
+	t.Helper()
+	if allowMissingTool(tool) {
+		// TODO(adonovan): if we skip because of (e.g.)
+		// mismatched go env GOROOT and runtime.GOROOT, don't
+		// we risk some users not getting the coverage they expect?
+		// bcmills notes: this shouldn't be a concern as of CL 404134 (Go 1.19).
+		// We could probably safely get rid of that GOPATH consistency
+		// check entirely at this point.
+		t.Skipf("skipping because %s tool not available: %v", tool, err)
+	} else {
+		t.Fatalf("%s tool not available: %v", tool, err)
+	}
+}
+
+// NeedsGoPackages skips t if the go/packages driver (or 'go' tool) implied by
+// the current process environment is not present in the path.
+func NeedsGoPackages(t testing.TB) {
+	t.Helper()
+
+	tool := os.Getenv("GOPACKAGESDRIVER")
+	switch tool {
+	case "off":
+		// "off" forces go/packages to use the go command.
+		tool = "go"
+	case "":
+		if _, err := exec.LookPath("gopackagesdriver"); err == nil {
+			tool = "gopackagesdriver"
+		} else {
+			tool = "go"
+		}
+	}
+
+	NeedsTool(t, tool)
+}
+
+// NeedsGoPackagesEnv skips t if the go/packages driver (or 'go' tool) implied
+// by env is not present in the path.
+func NeedsGoPackagesEnv(t testing.TB, env []string) {
+	t.Helper()
+
+	for _, v := range env {
+		if strings.HasPrefix(v, "GOPACKAGESDRIVER=") {
+			tool := strings.TrimPrefix(v, "GOPACKAGESDRIVER=")
+			if tool == "off" {
+				NeedsTool(t, "go")
+			} else {
+				NeedsTool(t, tool)
+			}
+			return
+		}
+	}
+
+	NeedsGoPackages(t)
+}
+
+// NeedsGoBuild skips t if the current system can't build programs with “go build”
+// and then run them with os.StartProcess or exec.Command.
+// Android doesn't have the userspace go build needs to run,
+// and js/wasm doesn't support running subprocesses.
+func NeedsGoBuild(t testing.TB) {
+	t.Helper()
+
+	// This logic was derived from internal/testing.HasGoBuild and
+	// may need to be updated as that function evolves.
+
+	NeedsTool(t, "go")
+}
+
+// ExitIfSmallMachine emits a helpful diagnostic and calls os.Exit(0) if the
+// current machine is a builder known to have scarce resources.
+//
+// It should be called from within a TestMain function.
+func ExitIfSmallMachine() {
+	switch b := os.Getenv("GO_BUILDER_NAME"); b {
+	case "linux-arm-scaleway":
+		// "linux-arm" was renamed to "linux-arm-scaleway" in CL 303230.
+		fmt.Fprintln(os.Stderr, "skipping test: linux-arm-scaleway builder lacks sufficient memory (https://golang.org/issue/32834)")
+	case "plan9-arm":
+		fmt.Fprintln(os.Stderr, "skipping test: plan9-arm builder lacks sufficient memory (https://golang.org/issue/38772)")
+	case "netbsd-arm-bsiegert", "netbsd-arm64-bsiegert":
+		// As of 2021-06-02, these builders are running with GO_TEST_TIMEOUT_SCALE=10,
+		// and there is only one of each. We shouldn't waste those scarce resources
+		// running very slow tests.
+		fmt.Fprintf(os.Stderr, "skipping test: %s builder is very slow\n", b)
+	case "dragonfly-amd64":
+		// As of 2021-11-02, this builder is running with GO_TEST_TIMEOUT_SCALE=2,
+		// and seems to have unusually slow disk performance.
+		fmt.Fprintln(os.Stderr, "skipping test: dragonfly-amd64 has slow disk (https://golang.org/issue/45216)")
+	case "linux-riscv64-unmatched":
+		// As of 2021-11-03, this builder is empirically not fast enough to run
+		// gopls tests. Ideally we should make the tests faster in short mode
+		// and/or fix them to not assume arbitrary deadlines.
+		// For now, we'll skip them instead.
+		fmt.Fprintf(os.Stderr, "skipping test: %s builder is too slow (https://golang.org/issue/49321)\n", b)
+	default:
+		switch runtime.GOOS {
+		case "android", "ios":
+			fmt.Fprintf(os.Stderr, "skipping test: assuming that %s is resource-constrained\n", runtime.GOOS)
+		default:
+			return
+		}
+	}
+	os.Exit(0)
+}
+
+// Go1Point returns the x in Go 1.x.
+func Go1Point() int {
+	for i := len(build.Default.ReleaseTags) - 1; i >= 0; i-- {
+		var version int
+		if _, err := fmt.Sscanf(build.Default.ReleaseTags[i], "go1.%d", &version); err != nil {
+			continue
+		}
+		return version
+	}
+	panic("bad release tags")
+}
+
+// NeedsGo1Point skips t if the Go version used to run the test is older than
+// 1.x.
+func NeedsGo1Point(t testing.TB, x int) {
+	if Go1Point() < x {
+		t.Helper()
+		t.Skipf("running Go version %q is version 1.%d, older than required 1.%d", runtime.Version(), Go1Point(), x)
+	}
+}
+
+// SkipAfterGo1Point skips t if the Go version used to run the test is newer than
+// 1.x.
+func SkipAfterGo1Point(t testing.TB, x int) {
+	if Go1Point() > x {
+		t.Helper()
+		t.Skipf("running Go version %q is version 1.%d, newer than maximum 1.%d", runtime.Version(), Go1Point(), x)
+	}
+}
+
+// NeedsLocalhostNet skips t if networking does not work for ports opened
+// with "localhost".
+func NeedsLocalhostNet(t testing.TB) {
+	switch runtime.GOOS {
+	case "js", "wasip1":
+		t.Skipf(`Listening on "localhost" fails on %s; see https://go.dev/issue/59718`, runtime.GOOS)
+	}
+}
+
+// Deadline returns the deadline of t, if known,
+// using the Deadline method added in Go 1.15.
+func Deadline(t testing.TB) (time.Time, bool) {
+	td, ok := t.(interface {
+		Deadline() (time.Time, bool)
+	})
+	if !ok {
+		return time.Time{}, false
+	}
+	return td.Deadline()
+}
+
+// WriteImportcfg writes an importcfg file used by the compiler or linker to
+// dstPath containing entries for the packages in std and cmd in addition
+// to the package to package file mappings in additionalPackageFiles.
+func WriteImportcfg(t testing.TB, dstPath string, additionalPackageFiles map[string]string) {
+	importcfg, err := goroot.Importcfg()
+	for k, v := range additionalPackageFiles {
+		importcfg += fmt.Sprintf("\npackagefile %s=%s", k, v)
+	}
+	if err != nil {
+		t.Fatalf("preparing the importcfg failed: %s", err)
+	}
+	os.WriteFile(dstPath, []byte(importcfg), 0655)
+	if err != nil {
+		t.Fatalf("writing the importcfg failed: %s", err)
+	}
+}
+
+var (
+	gorootOnce sync.Once
+	gorootPath string
+	gorootErr  error
+)
+
+func findGOROOT() (string, error) {
+	gorootOnce.Do(func() {
+		gorootPath = runtime.GOROOT()
+		if gorootPath != "" {
+			// If runtime.GOROOT() is non-empty, assume that it is valid. (It might
+			// not be: for example, the user may have explicitly set GOROOT
+			// to the wrong directory.)
+			return
+		}
+
+		cmd := exec.Command("go", "env", "GOROOT")
+		out, err := cmd.Output()
+		if err != nil {
+			gorootErr = fmt.Errorf("%v: %v", cmd, err)
+		}
+		gorootPath = strings.TrimSpace(string(out))
+	})
+
+	return gorootPath, gorootErr
+}
+
+// GOROOT reports the path to the directory containing the root of the Go
+// project source tree. This is normally equivalent to runtime.GOROOT, but
+// works even if the test binary was built with -trimpath.
+//
+// If GOROOT cannot be found, GOROOT skips t if t is non-nil,
+// or panics otherwise.
+func GOROOT(t testing.TB) string {
+	path, err := findGOROOT()
+	if err != nil {
+		if t == nil {
+			panic(err)
+		}
+		t.Helper()
+		t.Skip(err)
+	}
+	return path
+}
+
+// NeedsLocalXTools skips t if the golang.org/x/tools module is replaced and
+// its replacement directory does not exist (or does not contain the module).
+func NeedsLocalXTools(t testing.TB) {
+	t.Helper()
+
+	NeedsTool(t, "go")
+
+	cmd := Command(t, "go", "list", "-f", "{{with .Replace}}{{.Dir}}{{end}}", "-m", "golang.org/x/tools")
+	out, err := cmd.Output()
+	if err != nil {
+		if ee, ok := err.(*exec.ExitError); ok && len(ee.Stderr) > 0 {
+			t.Skipf("skipping test: %v: %v\n%s", cmd, err, ee.Stderr)
+		}
+		t.Skipf("skipping test: %v: %v", cmd, err)
+	}
+
+	dir := string(bytes.TrimSpace(out))
+	if dir == "" {
+		// No replacement directory, and (since we didn't set -e) no error either.
+		// Maybe x/tools isn't replaced at all (as in a gopls release, or when
+		// using a go.work file that includes the x/tools module).
+		return
+	}
+
+	// We found the directory where x/tools would exist if we're in a clone of the
+	// repo. Is it there? (If not, we're probably in the module cache instead.)
+	modFilePath := filepath.Join(dir, "go.mod")
+	b, err := os.ReadFile(modFilePath)
+	if err != nil {
+		t.Skipf("skipping test: x/tools replacement not found: %v", err)
+	}
+	modulePath := modfile.ModulePath(b)
+
+	if want := "golang.org/x/tools"; modulePath != want {
+		t.Skipf("skipping test: %s module path is %q, not %q", modFilePath, modulePath, want)
+	}
+}
+
+// NeedsGoExperiment skips t if the current process environment does not
+// have a GOEXPERIMENT flag set.
+func NeedsGoExperiment(t testing.TB, flag string) {
+	t.Helper()
+
+	goexp := os.Getenv("GOEXPERIMENT")
+	set := false
+	for _, f := range strings.Split(goexp, ",") {
+		if f == "" {
+			continue
+		}
+		if f == "none" {
+			// GOEXPERIMENT=none disables all experiment flags.
+			set = false
+			break
+		}
+		val := true
+		if strings.HasPrefix(f, "no") {
+			f, val = f[2:], false
+		}
+		if f == flag {
+			set = val
+		}
+	}
+	if !set {
+		t.Skipf("skipping test: flag %q is not set in GOEXPERIMENT=%q", flag, goexp)
+	}
+}
diff --git a/internal/testenv/testenv_notunix.go b/internal/testenv/testenv_notunix.go
new file mode 100644
index 0000000..e9ce0d3
--- /dev/null
+++ b/internal/testenv/testenv_notunix.go
@@ -0,0 +1,14 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !(unix || aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris)
+// +build !unix,!aix,!darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!solaris
+
+package testenv
+
+import "os"
+
+// Sigquit is the signal to send to kill a hanging subprocess.
+// On Unix we send SIGQUIT, but on non-Unix we only have os.Kill.
+var Sigquit = os.Kill
diff --git a/internal/testenv/testenv_unix.go b/internal/testenv/testenv_unix.go
new file mode 100644
index 0000000..bc6af1f
--- /dev/null
+++ b/internal/testenv/testenv_unix.go
@@ -0,0 +1,14 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build unix || aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
+// +build unix aix darwin dragonfly freebsd linux netbsd openbsd solaris
+
+package testenv
+
+import "syscall"
+
+// Sigquit is the signal to send to kill a hanging subprocess.
+// Send SIGQUIT to get a stack trace.
+var Sigquit = syscall.SIGQUIT
diff --git a/pkg/gen/generator.go b/pkg/gen/generator.go
index 892012a..438ea99 100644
--- a/pkg/gen/generator.go
+++ b/pkg/gen/generator.go
@@ -3,6 +3,7 @@ package gen
 import (
 	"bytes"
 	"embed"
+	"errors"
 	"fmt"
 	"go/ast"
 	"go/format"
@@ -25,8 +26,10 @@ var templates = template.Must(template.New("templates").Funcs(template.FuncMap{
 }).ParseFS(content, "templates/*.go.tmpl"))
 
 type Generator struct {
-	bytes.Buffer
-	*Package    // Package we are scanning.
+	buf  bytes.Buffer
+	pkg  *Package                                 // Package we are scanning.
+	logf func(format string, args ...interface{}) // test logging hook; nil when not testing
+
 	TrimPrefix  string
 	LineComment bool
 }
@@ -38,11 +41,17 @@ func New(trimPrefix string, lineComment bool) *Generator {
 	}
 }
 
+var (
+	ErrTooManyPackages = errors.New("too many package")
+)
+
+// ParsePackage analyzes the single package constructed from the patterns and tags.
 func (g *Generator) ParsePackage(patterns []string, tags []string) (err error) {
 	cfg := &packages.Config{
-		Mode:       packages.LoadSyntax,
+		Mode:       packages.NeedName | packages.NeedTypes | packages.NeedTypesInfo | packages.NeedSyntax,
 		Tests:      false,
 		BuildFlags: []string{fmt.Sprintf("-tags=%s", strings.Join(tags, " "))},
+		Logf:       g.logf,
 	}
 
 	pkgs, err := packages.Load(cfg, patterns...)
@@ -52,7 +61,7 @@ func (g *Generator) ParsePackage(patterns []string, tags []string) (err error) {
 	}
 
 	if len(pkgs) != 1 {
-		err = fmt.Errorf("too many package")
+		err = fmt.Errorf("%d packages matching %v, %w", len(pkgs), strings.Join(patterns, " "), ErrTooManyPackages)
 		return
 	}
 
@@ -63,16 +72,16 @@ func (g *Generator) ParsePackage(patterns []string, tags []string) (err error) {
 
 // addPackage adds a type checked Package and its syntax files to the generator.
 func (g *Generator) addPackage(pkg *packages.Package) {
-	g.Package = &Package{
+	g.pkg = &Package{
 		Name:  pkg.Name,
 		Defs:  pkg.TypesInfo.Defs,
 		Files: make([]*File, len(pkg.Syntax)),
 	}
 
 	for i, file := range pkg.Syntax {
-		g.Package.Files[i] = &File{
+		g.pkg.Files[i] = &File{
 			File:        file,
-			Package:     g.Package,
+			Package:     g.pkg,
 			TrimPrefix:  g.TrimPrefix,
 			LineComment: g.LineComment,
 		}
@@ -80,16 +89,16 @@ func (g *Generator) addPackage(pkg *packages.Package) {
 }
 
 func (g *Generator) GenerateHeader() error {
-	return templates.Lookup("header.go.tmpl").Execute(g, map[string]interface{}{
+	return templates.Lookup("header.go.tmpl").Execute(&g.buf, map[string]interface{}{
 		"CmdLine": strings.Join(append([]string{filepath.Base(os.Args[0])}, os.Args[1:]...), " "),
-		"Package": g.Package,
+		"Package": g.pkg,
 	})
 }
 
 // generate produces the String method for the named type.
 func (g *Generator) Generate(typeName string) (err error) {
 	values := make([]Value, 0, 100)
-	for _, file := range g.Package.Files {
+	for _, file := range g.pkg.Files {
 		// Set the state for this run of the walker.
 		file.TypeName = typeName
 		file.Values = nil
@@ -105,7 +114,7 @@ func (g *Generator) Generate(typeName string) (err error) {
 	}
 
 	// Generate code that will fail if the constants change value.
-	if err = templates.Lookup("validate.go.tmpl").Execute(g, values); err != nil {
+	if err = templates.Lookup("validate.go.tmpl").Execute(&g.buf, values); err != nil {
 		return
 	}
 
@@ -119,7 +128,7 @@ func (g *Generator) Generate(typeName string) (err error) {
 		}
 	}
 
-	if err = templates.Lookup("props.go.tmpl").Execute(g, map[string]interface{}{
+	if err = templates.Lookup("props.go.tmpl").Execute(&g.buf, map[string]interface{}{
 		"Type":   typeName,
 		"Values": values,
 	}); err != nil {
@@ -180,7 +189,7 @@ func (g *Generator) declareIndexAndNameVars(runs [][]Value, typeName string) err
 		}
 	}
 
-	return templates.Lookup("index_and_name.go.tmpl").Execute(g, map[string]interface{}{
+	return templates.Lookup("index_and_name.go.tmpl").Execute(&g.buf, map[string]interface{}{
 		"Runs":    runs,
 		"Indexes": indexes,
 		"Type":    typeName,
@@ -201,16 +210,16 @@ func (g *Generator) declareMapAndNameVars(values []Value, typeName string) error
 		off += len(v.OriginalName)
 	}
 
-	return templates.Lookup("map_and_name.go.tmpl").Execute(g, map[string]interface{}{
+	return templates.Lookup("map_and_name.go.tmpl").Execute(&g.buf, map[string]interface{}{
 		"Values": _values,
 		"Type":   typeName,
 	})
 }
 
 func (g *Generator) Format() []byte {
-	src, err := format.Source(g.Buffer.Bytes())
+	src, err := format.Source(g.buf.Bytes())
 	if err != nil {
-		return g.Buffer.Bytes()
+		return g.buf.Bytes()
 	}
 	return src
 }
diff --git a/pkg/gen/golden_test.go b/pkg/gen/golden_test.go
new file mode 100644
index 0000000..174b12e
--- /dev/null
+++ b/pkg/gen/golden_test.go
@@ -0,0 +1,81 @@
+package gen
+
+import (
+	"embed"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/flier/go-bitflags/internal/testenv"
+)
+
+// Golden represents a test case.
+type Golden struct {
+	name        string
+	trimPrefix  string
+	lineComment bool
+	typeName    string
+	input       string // input; the package clause is provided when running the test.
+	output      string // expected output.
+}
+
+//go:embed testdata/*.go
+var testdata embed.FS
+
+var golden = []Golden{
+	{"pill", "", false, "Pill", "pill_in.go", "pill_out.go"},
+}
+
+const head = `package test
+
+import (
+	"strconv"
+	"strings"
+)
+
+`
+
+func TestGolden(t *testing.T) {
+	testenv.NeedsTool(t, "go")
+
+	dir := t.TempDir()
+	for _, test := range golden {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			g := Generator{
+				TrimPrefix:  test.trimPrefix,
+				LineComment: test.lineComment,
+				logf:        t.Logf,
+			}
+
+			file := test.name + ".go"
+			absFile := filepath.Join(dir, file)
+
+			buf, err := testdata.ReadFile("testdata/" + test.input)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if err = os.WriteFile(absFile, buf, 0644); err != nil {
+				t.Fatal(err)
+			}
+
+			g.ParsePackage([]string{absFile}, nil)
+
+			if err = g.Generate(test.typeName); err != nil {
+				t.Fatal(err)
+			}
+
+			got := head + strings.ReplaceAll(string(g.Format()), "\r\n", "\n")
+
+			if buf, err = testdata.ReadFile("testdata/" + test.output); err != nil {
+				t.Fatal(err)
+			}
+
+			if expected := strings.ReplaceAll(string(buf), "\r\n", "\n"); got != expected {
+				t.Errorf("%s: got(%d)\n====\n%q\n====\nexpected(%d)\n====\n%q", test.name, len(got), got, len(expected), expected)
+			}
+		})
+	}
+}
diff --git a/pkg/gen/testdata/pill_in.go b/pkg/gen/testdata/pill_in.go
new file mode 100644
index 0000000..e492252
--- /dev/null
+++ b/pkg/gen/testdata/pill_in.go
@@ -0,0 +1,11 @@
+package test
+
+type Pill int
+
+const (
+	Placebo Pill = 1 << iota
+	Aspirin
+	Ibuprofen
+	Paracetamol
+	Acetaminophen = Paracetamol
+)
diff --git a/pkg/gen/testdata/pill_out.go b/pkg/gen/testdata/pill_out.go
new file mode 100644
index 0000000..b6037ec
--- /dev/null
+++ b/pkg/gen/testdata/pill_out.go
@@ -0,0 +1,82 @@
+package test
+
+import (
+	"strconv"
+	"strings"
+)
+
+func _() {
+	// An "invalid array index" compiler error signifies that the constant values have changed.
+	// Re-run the stringer command to generate them again.
+	var x [1]struct{}
+
+	_ = x[Placebo-1]
+	_ = x[Aspirin-2]
+	_ = x[Ibuprofen-4]
+	_ = x[Paracetamol-8]
+}
+
+const (
+	_Pill_name_0 = "PlaceboAspirin"
+	_Pill_name_1 = "Ibuprofen"
+	_Pill_name_2 = "Paracetamol"
+)
+
+var (
+	_Pill_index_0 = [...]uint{0, 7, 14}
+)
+
+func (i Pill) Name() string {
+	switch {
+	case i == 4:
+		return _Pill_name_1
+	case i == 8:
+		return _Pill_name_2
+	default:
+		return "Pill(" + strconv.FormatInt(int64(i), 10) + ")"
+	}
+}
+
+func (i Pill) Contains(f Pill) bool { return (i & f) == f }
+
+func (i Pill) Placebo() bool { return i.Contains(Placebo) }
+
+func (i Pill) Aspirin() bool { return i.Contains(Aspirin) }
+
+func (i Pill) Ibuprofen() bool { return i.Contains(Ibuprofen) }
+
+func (i Pill) Paracetamol() bool { return i.Contains(Paracetamol) }
+
+func (i Pill) String() string {
+	var b strings.Builder
+
+	if i.Placebo() {
+		if b.Len() > 0 {
+			b.WriteByte('|')
+		}
+		b.WriteString("Placebo")
+	}
+
+	if i.Aspirin() {
+		if b.Len() > 0 {
+			b.WriteByte('|')
+		}
+		b.WriteString("Aspirin")
+	}
+
+	if i.Ibuprofen() {
+		if b.Len() > 0 {
+			b.WriteByte('|')
+		}
+		b.WriteString("Ibuprofen")
+	}
+
+	if i.Paracetamol() {
+		if b.Len() > 0 {
+			b.WriteByte('|')
+		}
+		b.WriteString("Paracetamol")
+	}
+
+	return b.String()
+}
diff --git a/vendor/github.com/hashicorp/errwrap/go.mod b/vendor/github.com/hashicorp/errwrap/go.mod
deleted file mode 100644
index c9b8402..0000000
--- a/vendor/github.com/hashicorp/errwrap/go.mod
+++ /dev/null
@@ -1 +0,0 @@
-module github.com/hashicorp/errwrap
diff --git a/vendor/github.com/hashicorp/go-multierror/go.mod b/vendor/github.com/hashicorp/go-multierror/go.mod
deleted file mode 100644
index 141cc4c..0000000
--- a/vendor/github.com/hashicorp/go-multierror/go.mod
+++ /dev/null
@@ -1,5 +0,0 @@
-module github.com/hashicorp/go-multierror
-
-go 1.13
-
-require github.com/hashicorp/errwrap v1.0.0
diff --git a/vendor/github.com/hashicorp/go-multierror/go.sum b/vendor/github.com/hashicorp/go-multierror/go.sum
deleted file mode 100644
index e8238e9..0000000
--- a/vendor/github.com/hashicorp/go-multierror/go.sum
+++ /dev/null
@@ -1,2 +0,0 @@
-github.com/hashicorp/errwrap v1.0.0 h1:hLrqtEDnRye3+sgx6z4qVLNuviH3MR5aQ0ykNJa/UYA=
-github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
diff --git a/vendor/github.com/jpillora/opts/go.mod b/vendor/github.com/jpillora/opts/go.mod
deleted file mode 100644
index b3c52b0..0000000
--- a/vendor/github.com/jpillora/opts/go.mod
+++ /dev/null
@@ -1,5 +0,0 @@
-module github.com/jpillora/opts
-
-go 1.12
-
-require github.com/posener/complete v1.2.2-0.20190308074557-af07aa5181b3
diff --git a/vendor/github.com/jpillora/opts/go.sum b/vendor/github.com/jpillora/opts/go.sum
deleted file mode 100644
index 8ccca51..0000000
--- a/vendor/github.com/jpillora/opts/go.sum
+++ /dev/null
@@ -1,6 +0,0 @@
-github.com/hashicorp/errwrap v1.0.0 h1:hLrqtEDnRye3+sgx6z4qVLNuviH3MR5aQ0ykNJa/UYA=
-github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
-github.com/hashicorp/go-multierror v1.0.0 h1:iVjPR7a6H0tWELX5NxNe7bYopibicUzc7uPribsnS6o=
-github.com/hashicorp/go-multierror v1.0.0/go.mod h1:dHtQlpGsu+cZNNAkkCN/P3hoUDHhCYQXV3UM06sGGrk=
-github.com/posener/complete v1.2.2-0.20190308074557-af07aa5181b3 h1:GqpA1/5oN1NgsxoSA4RH0YWTaqvUlQNeOpHXD/JRbOQ=
-github.com/posener/complete v1.2.2-0.20190308074557-af07aa5181b3/go.mod h1:6gapUrK/U1TAN7ciCoNRIdVC5sbdBTUh1DKN0g6uH7E=
diff --git a/vendor/github.com/posener/complete/go.mod b/vendor/github.com/posener/complete/go.mod
deleted file mode 100644
index 6d82a98..0000000
--- a/vendor/github.com/posener/complete/go.mod
+++ /dev/null
@@ -1,8 +0,0 @@
-module github.com/posener/complete
-
-require (
-	github.com/hashicorp/go-multierror v1.0.0
-	github.com/stretchr/testify v1.4.0
-)
-
-go 1.13
diff --git a/vendor/github.com/posener/complete/go.sum b/vendor/github.com/posener/complete/go.sum
deleted file mode 100644
index accaa27..0000000
--- a/vendor/github.com/posener/complete/go.sum
+++ /dev/null
@@ -1,15 +0,0 @@
-github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/hashicorp/errwrap v1.0.0 h1:hLrqtEDnRye3+sgx6z4qVLNuviH3MR5aQ0ykNJa/UYA=
-github.com/hashicorp/errwrap v1.0.0/go.mod h1:YH+1FKiLXxHSkmPseP+kNlulaMuP3n2brvKWEqk/Jc4=
-github.com/hashicorp/go-multierror v1.0.0 h1:iVjPR7a6H0tWELX5NxNe7bYopibicUzc7uPribsnS6o=
-github.com/hashicorp/go-multierror v1.0.0/go.mod h1:dHtQlpGsu+cZNNAkkCN/P3hoUDHhCYQXV3UM06sGGrk=
-github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
-github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
-github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
-gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
diff --git a/vendor/golang.org/x/mod/semver/semver.go b/vendor/golang.org/x/mod/semver/semver.go
index 7be398f..9a2dfd3 100644
--- a/vendor/golang.org/x/mod/semver/semver.go
+++ b/vendor/golang.org/x/mod/semver/semver.go
@@ -32,7 +32,6 @@ type parsed struct {
 	short      string
 	prerelease string
 	build      string
-	err        string
 }
 
 // IsValid reports whether v is a valid semantic version string.
@@ -141,7 +140,7 @@ func Compare(v, w string) int {
 // Max canonicalizes its arguments and then returns the version string
 // that compares greater.
 //
-// Deprecated: use Compare instead. In most cases, returning a canonicalized
+// Deprecated: use [Compare] instead. In most cases, returning a canonicalized
 // version is not expected or desired.
 func Max(v, w string) string {
 	v = Canonical(v)
@@ -152,7 +151,7 @@ func Max(v, w string) string {
 	return w
 }
 
-// ByVersion implements sort.Interface for sorting semantic version strings.
+// ByVersion implements [sort.Interface] for sorting semantic version strings.
 type ByVersion []string
 
 func (vs ByVersion) Len() int      { return len(vs) }
@@ -165,19 +164,17 @@ func (vs ByVersion) Less(i, j int) bool {
 	return vs[i] < vs[j]
 }
 
-// Sort sorts a list of semantic version strings using ByVersion.
+// Sort sorts a list of semantic version strings using [ByVersion].
 func Sort(list []string) {
 	sort.Sort(ByVersion(list))
 }
 
 func parse(v string) (p parsed, ok bool) {
 	if v == "" || v[0] != 'v' {
-		p.err = "missing v prefix"
 		return
 	}
 	p.major, v, ok = parseInt(v[1:])
 	if !ok {
-		p.err = "bad major version"
 		return
 	}
 	if v == "" {
@@ -187,13 +184,11 @@ func parse(v string) (p parsed, ok bool) {
 		return
 	}
 	if v[0] != '.' {
-		p.err = "bad minor prefix"
 		ok = false
 		return
 	}
 	p.minor, v, ok = parseInt(v[1:])
 	if !ok {
-		p.err = "bad minor version"
 		return
 	}
 	if v == "" {
@@ -202,31 +197,26 @@ func parse(v string) (p parsed, ok bool) {
 		return
 	}
 	if v[0] != '.' {
-		p.err = "bad patch prefix"
 		ok = false
 		return
 	}
 	p.patch, v, ok = parseInt(v[1:])
 	if !ok {
-		p.err = "bad patch version"
 		return
 	}
 	if len(v) > 0 && v[0] == '-' {
 		p.prerelease, v, ok = parsePrerelease(v)
 		if !ok {
-			p.err = "bad prerelease"
 			return
 		}
 	}
 	if len(v) > 0 && v[0] == '+' {
 		p.build, v, ok = parseBuild(v)
 		if !ok {
-			p.err = "bad build"
 			return
 		}
 	}
 	if v != "" {
-		p.err = "junk on end"
 		ok = false
 		return
 	}
diff --git a/vendor/golang.org/x/sys/LICENSE b/vendor/golang.org/x/sys/LICENSE
deleted file mode 100644
index 6a66aea..0000000
--- a/vendor/golang.org/x/sys/LICENSE
+++ /dev/null
@@ -1,27 +0,0 @@
-Copyright (c) 2009 The Go Authors. All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/golang.org/x/sys/PATENTS b/vendor/golang.org/x/sys/PATENTS
deleted file mode 100644
index 7330990..0000000
--- a/vendor/golang.org/x/sys/PATENTS
+++ /dev/null
@@ -1,22 +0,0 @@
-Additional IP Rights Grant (Patents)
-
-"This implementation" means the copyrightable works distributed by
-Google as part of the Go project.
-
-Google hereby grants to You a perpetual, worldwide, non-exclusive,
-no-charge, royalty-free, irrevocable (except as stated in this section)
-patent license to make, have made, use, offer to sell, sell, import,
-transfer and otherwise run, modify and propagate the contents of this
-implementation of Go, where such license applies only to those patent
-claims, both currently owned or controlled by Google and acquired in
-the future, licensable by Google that are necessarily infringed by this
-implementation of Go.  This grant does not include claims that would be
-infringed only as a consequence of further modification of this
-implementation.  If you or your agent or exclusive licensee institute or
-order or agree to the institution of patent litigation against any
-entity (including a cross-claim or counterclaim in a lawsuit) alleging
-that this implementation of Go or any code incorporated within this
-implementation of Go constitutes direct or contributory patent
-infringement, or inducement of patent infringement, then any patent
-rights granted to you under this License for this implementation of Go
-shall terminate as of the date such litigation is filed.
diff --git a/vendor/golang.org/x/sys/execabs/execabs.go b/vendor/golang.org/x/sys/execabs/execabs.go
deleted file mode 100644
index b981cfb..0000000
--- a/vendor/golang.org/x/sys/execabs/execabs.go
+++ /dev/null
@@ -1,102 +0,0 @@
-// Copyright 2020 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package execabs is a drop-in replacement for os/exec
-// that requires PATH lookups to find absolute paths.
-// That is, execabs.Command("cmd") runs the same PATH lookup
-// as exec.Command("cmd"), but if the result is a path
-// which is relative, the Run and Start methods will report
-// an error instead of running the executable.
-//
-// See https://blog.golang.org/path-security for more information
-// about when it may be necessary or appropriate to use this package.
-package execabs
-
-import (
-	"context"
-	"fmt"
-	"os/exec"
-	"path/filepath"
-	"reflect"
-	"unsafe"
-)
-
-// ErrNotFound is the error resulting if a path search failed to find an executable file.
-// It is an alias for exec.ErrNotFound.
-var ErrNotFound = exec.ErrNotFound
-
-// Cmd represents an external command being prepared or run.
-// It is an alias for exec.Cmd.
-type Cmd = exec.Cmd
-
-// Error is returned by LookPath when it fails to classify a file as an executable.
-// It is an alias for exec.Error.
-type Error = exec.Error
-
-// An ExitError reports an unsuccessful exit by a command.
-// It is an alias for exec.ExitError.
-type ExitError = exec.ExitError
-
-func relError(file, path string) error {
-	return fmt.Errorf("%s resolves to executable in current directory (.%c%s)", file, filepath.Separator, path)
-}
-
-// LookPath searches for an executable named file in the directories
-// named by the PATH environment variable. If file contains a slash,
-// it is tried directly and the PATH is not consulted. The result will be
-// an absolute path.
-//
-// LookPath differs from exec.LookPath in its handling of PATH lookups,
-// which are used for file names without slashes. If exec.LookPath's
-// PATH lookup would have returned an executable from the current directory,
-// LookPath instead returns an error.
-func LookPath(file string) (string, error) {
-	path, err := exec.LookPath(file)
-	if err != nil && !isGo119ErrDot(err) {
-		return "", err
-	}
-	if filepath.Base(file) == file && !filepath.IsAbs(path) {
-		return "", relError(file, path)
-	}
-	return path, nil
-}
-
-func fixCmd(name string, cmd *exec.Cmd) {
-	if filepath.Base(name) == name && !filepath.IsAbs(cmd.Path) {
-		// exec.Command was called with a bare binary name and
-		// exec.LookPath returned a path which is not absolute.
-		// Set cmd.lookPathErr and clear cmd.Path so that it
-		// cannot be run.
-		lookPathErr := (*error)(unsafe.Pointer(reflect.ValueOf(cmd).Elem().FieldByName("lookPathErr").Addr().Pointer()))
-		if *lookPathErr == nil {
-			*lookPathErr = relError(name, cmd.Path)
-		}
-		cmd.Path = ""
-	}
-}
-
-// CommandContext is like Command but includes a context.
-//
-// The provided context is used to kill the process (by calling os.Process.Kill)
-// if the context becomes done before the command completes on its own.
-func CommandContext(ctx context.Context, name string, arg ...string) *exec.Cmd {
-	cmd := exec.CommandContext(ctx, name, arg...)
-	fixCmd(name, cmd)
-	return cmd
-
-}
-
-// Command returns the Cmd struct to execute the named program with the given arguments.
-// See exec.Command for most details.
-//
-// Command differs from exec.Command in its handling of PATH lookups,
-// which are used when the program name contains no slashes.
-// If exec.Command would have returned an exec.Cmd configured to run an
-// executable from the current directory, Command instead
-// returns an exec.Cmd that will return an error from Start or Run.
-func Command(name string, arg ...string) *exec.Cmd {
-	cmd := exec.Command(name, arg...)
-	fixCmd(name, cmd)
-	return cmd
-}
diff --git a/vendor/golang.org/x/tools/AUTHORS b/vendor/golang.org/x/tools/AUTHORS
deleted file mode 100644
index 15167cd..0000000
--- a/vendor/golang.org/x/tools/AUTHORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code refers to The Go Authors for copyright purposes.
-# The master list of authors is in the main Go distribution,
-# visible at http://tip.golang.org/AUTHORS.
diff --git a/vendor/golang.org/x/tools/CONTRIBUTORS b/vendor/golang.org/x/tools/CONTRIBUTORS
deleted file mode 100644
index 1c4577e..0000000
--- a/vendor/golang.org/x/tools/CONTRIBUTORS
+++ /dev/null
@@ -1,3 +0,0 @@
-# This source code was written by the Go contributors.
-# The master list of contributors is in the main Go distribution,
-# visible at http://tip.golang.org/CONTRIBUTORS.
diff --git a/vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go b/vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go
index cec819d..03543bd 100644
--- a/vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go
+++ b/vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go
@@ -17,32 +17,46 @@
 // developer tools, which will then be able to consume both Go 1.7 and
 // Go 1.8 export data files, so they will work before and after the
 // Go update. (See discussion at https://golang.org/issue/15651.)
-//
 package gcexportdata // import "golang.org/x/tools/go/gcexportdata"
 
 import (
 	"bufio"
 	"bytes"
+	"encoding/json"
 	"fmt"
 	"go/token"
 	"go/types"
 	"io"
-	"io/ioutil"
+	"os/exec"
 
-	"golang.org/x/tools/go/internal/gcimporter"
+	"golang.org/x/tools/internal/gcimporter"
 )
 
 // Find returns the name of an object (.o) or archive (.a) file
 // containing type information for the specified import path,
-// using the workspace layout conventions of go/build.
+// using the go command.
 // If no file was found, an empty filename is returned.
 //
 // A relative srcDir is interpreted relative to the current working directory.
 //
 // Find also returns the package's resolved (canonical) import path,
 // reflecting the effects of srcDir and vendoring on importPath.
+//
+// Deprecated: Use the higher-level API in golang.org/x/tools/go/packages,
+// which is more efficient.
 func Find(importPath, srcDir string) (filename, path string) {
-	return gcimporter.FindPkg(importPath, srcDir)
+	cmd := exec.Command("go", "list", "-json", "-export", "--", importPath)
+	cmd.Dir = srcDir
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return "", ""
+	}
+	var data struct {
+		ImportPath string
+		Export     string
+	}
+	json.Unmarshal(out, &data)
+	return data.Export, data.ImportPath
 }
 
 // NewReader returns a reader for the export data section of an object
@@ -70,9 +84,26 @@ func NewReader(r io.Reader) (io.Reader, error) {
 	}
 }
 
+// readAll works the same way as io.ReadAll, but avoids allocations and copies
+// by preallocating a byte slice of the necessary size if the size is known up
+// front. This is always possible when the input is an archive. In that case,
+// NewReader will return the known size using an io.LimitedReader.
+func readAll(r io.Reader) ([]byte, error) {
+	if lr, ok := r.(*io.LimitedReader); ok {
+		data := make([]byte, lr.N)
+		_, err := io.ReadFull(lr, data)
+		return data, err
+	}
+	return io.ReadAll(r)
+}
+
 // Read reads export data from in, decodes it, and returns type
 // information for the package.
-// The package name is specified by path.
+//
+// The package path (effectively its linker symbol prefix) is
+// specified by path, since unlike the package name, this information
+// may not be recorded in the export data.
+//
 // File position information is added to fset.
 //
 // Read may inspect and add to the imports map to ensure that references
@@ -83,7 +114,7 @@ func NewReader(r io.Reader) (io.Reader, error) {
 //
 // On return, the state of the reader is undefined.
 func Read(in io.Reader, fset *token.FileSet, imports map[string]*types.Package, path string) (*types.Package, error) {
-	data, err := ioutil.ReadAll(in)
+	data, err := readAll(in)
 	if err != nil {
 		return nil, fmt.Errorf("reading export data for %q: %v", path, err)
 	}
@@ -92,22 +123,31 @@ func Read(in io.Reader, fset *token.FileSet, imports map[string]*types.Package,
 		return nil, fmt.Errorf("can't read export data for %q directly from an archive file (call gcexportdata.NewReader first to extract export data)", path)
 	}
 
-	// The App Engine Go runtime v1.6 uses the old export data format.
-	// TODO(adonovan): delete once v1.7 has been around for a while.
-	if bytes.HasPrefix(data, []byte("package ")) {
-		return gcimporter.ImportData(imports, path, path, bytes.NewReader(data))
-	}
-
 	// The indexed export format starts with an 'i'; the older
 	// binary export format starts with a 'c', 'd', or 'v'
 	// (from "version"). Select appropriate importer.
-	if len(data) > 0 && data[0] == 'i' {
-		_, pkg, err := gcimporter.IImportData(fset, imports, data[1:], path)
-		return pkg, err
-	}
+	if len(data) > 0 {
+		switch data[0] {
+		case 'v', 'c', 'd': // binary, till go1.10
+			return nil, fmt.Errorf("binary (%c) import format is no longer supported", data[0])
+
+		case 'i': // indexed, till go1.19
+			_, pkg, err := gcimporter.IImportData(fset, imports, data[1:], path)
+			return pkg, err
 
-	_, pkg, err := gcimporter.BImportData(fset, imports, data, path)
-	return pkg, err
+		case 'u': // unified, from go1.20
+			_, pkg, err := gcimporter.UImportData(fset, imports, data[1:], path)
+			return pkg, err
+
+		default:
+			l := len(data)
+			if l > 10 {
+				l = 10
+			}
+			return nil, fmt.Errorf("unexpected export data with prefix %q for path %s", string(data[:l]), path)
+		}
+	}
+	return nil, fmt.Errorf("empty export data for %s", path)
 }
 
 // Write writes encoded type information for the specified package to out.
@@ -130,7 +170,7 @@ func Write(out io.Writer, fset *token.FileSet, pkg *types.Package) error {
 //
 // Experimental: This API is experimental and may change in the future.
 func ReadBundle(in io.Reader, fset *token.FileSet, imports map[string]*types.Package) ([]*types.Package, error) {
-	data, err := ioutil.ReadAll(in)
+	data, err := readAll(in)
 	if err != nil {
 		return nil, fmt.Errorf("reading export bundle: %v", err)
 	}
diff --git a/vendor/golang.org/x/tools/go/gcexportdata/importer.go b/vendor/golang.org/x/tools/go/gcexportdata/importer.go
index efe221e..37a7247 100644
--- a/vendor/golang.org/x/tools/go/gcexportdata/importer.go
+++ b/vendor/golang.org/x/tools/go/gcexportdata/importer.go
@@ -23,6 +23,8 @@ import (
 // or to control the FileSet or access the imports map populated during
 // package loading.
 //
+// Deprecated: Use the higher-level API in golang.org/x/tools/go/packages,
+// which is more efficient.
 func NewImporter(fset *token.FileSet, imports map[string]*types.Package) types.ImporterFrom {
 	return importer{fset, imports}
 }
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go
deleted file mode 100644
index 0a3cdb9..0000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/bexport.go
+++ /dev/null
@@ -1,851 +0,0 @@
-// Copyright 2016 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Binary package export.
-// This file was derived from $GOROOT/src/cmd/compile/internal/gc/bexport.go;
-// see that file for specification of the format.
-
-package gcimporter
-
-import (
-	"bytes"
-	"encoding/binary"
-	"fmt"
-	"go/ast"
-	"go/constant"
-	"go/token"
-	"go/types"
-	"math"
-	"math/big"
-	"sort"
-	"strings"
-)
-
-// If debugFormat is set, each integer and string value is preceded by a marker
-// and position information in the encoding. This mechanism permits an importer
-// to recognize immediately when it is out of sync. The importer recognizes this
-// mode automatically (i.e., it can import export data produced with debugging
-// support even if debugFormat is not set at the time of import). This mode will
-// lead to massively larger export data (by a factor of 2 to 3) and should only
-// be enabled during development and debugging.
-//
-// NOTE: This flag is the first flag to enable if importing dies because of
-// (suspected) format errors, and whenever a change is made to the format.
-const debugFormat = false // default: false
-
-// Current export format version. Increase with each format change.
-// Note: The latest binary (non-indexed) export format is at version 6.
-//       This exporter is still at level 4, but it doesn't matter since
-//       the binary importer can handle older versions just fine.
-// 6: package height (CL 105038) -- NOT IMPLEMENTED HERE
-// 5: improved position encoding efficiency (issue 20080, CL 41619) -- NOT IMPLEMEMTED HERE
-// 4: type name objects support type aliases, uses aliasTag
-// 3: Go1.8 encoding (same as version 2, aliasTag defined but never used)
-// 2: removed unused bool in ODCL export (compiler only)
-// 1: header format change (more regular), export package for _ struct fields
-// 0: Go1.7 encoding
-const exportVersion = 4
-
-// trackAllTypes enables cycle tracking for all types, not just named
-// types. The existing compiler invariants assume that unnamed types
-// that are not completely set up are not used, or else there are spurious
-// errors.
-// If disabled, only named types are tracked, possibly leading to slightly
-// less efficient encoding in rare cases. It also prevents the export of
-// some corner-case type declarations (but those are not handled correctly
-// with with the textual export format either).
-// TODO(gri) enable and remove once issues caused by it are fixed
-const trackAllTypes = false
-
-type exporter struct {
-	fset *token.FileSet
-	out  bytes.Buffer
-
-	// object -> index maps, indexed in order of serialization
-	strIndex map[string]int
-	pkgIndex map[*types.Package]int
-	typIndex map[types.Type]int
-
-	// position encoding
-	posInfoFormat bool
-	prevFile      string
-	prevLine      int
-
-	// debugging support
-	written int // bytes written
-	indent  int // for trace
-}
-
-// internalError represents an error generated inside this package.
-type internalError string
-
-func (e internalError) Error() string { return "gcimporter: " + string(e) }
-
-func internalErrorf(format string, args ...interface{}) error {
-	return internalError(fmt.Sprintf(format, args...))
-}
-
-// BExportData returns binary export data for pkg.
-// If no file set is provided, position info will be missing.
-func BExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error) {
-	if !debug {
-		defer func() {
-			if e := recover(); e != nil {
-				if ierr, ok := e.(internalError); ok {
-					err = ierr
-					return
-				}
-				// Not an internal error; panic again.
-				panic(e)
-			}
-		}()
-	}
-
-	p := exporter{
-		fset:          fset,
-		strIndex:      map[string]int{"": 0}, // empty string is mapped to 0
-		pkgIndex:      make(map[*types.Package]int),
-		typIndex:      make(map[types.Type]int),
-		posInfoFormat: true, // TODO(gri) might become a flag, eventually
-	}
-
-	// write version info
-	// The version string must start with "version %d" where %d is the version
-	// number. Additional debugging information may follow after a blank; that
-	// text is ignored by the importer.
-	p.rawStringln(fmt.Sprintf("version %d", exportVersion))
-	var debug string
-	if debugFormat {
-		debug = "debug"
-	}
-	p.rawStringln(debug) // cannot use p.bool since it's affected by debugFormat; also want to see this clearly
-	p.bool(trackAllTypes)
-	p.bool(p.posInfoFormat)
-
-	// --- generic export data ---
-
-	// populate type map with predeclared "known" types
-	for index, typ := range predeclared() {
-		p.typIndex[typ] = index
-	}
-	if len(p.typIndex) != len(predeclared()) {
-		return nil, internalError("duplicate entries in type map?")
-	}
-
-	// write package data
-	p.pkg(pkg, true)
-	if trace {
-		p.tracef("\n")
-	}
-
-	// write objects
-	objcount := 0
-	scope := pkg.Scope()
-	for _, name := range scope.Names() {
-		if !ast.IsExported(name) {
-			continue
-		}
-		if trace {
-			p.tracef("\n")
-		}
-		p.obj(scope.Lookup(name))
-		objcount++
-	}
-
-	// indicate end of list
-	if trace {
-		p.tracef("\n")
-	}
-	p.tag(endTag)
-
-	// for self-verification only (redundant)
-	p.int(objcount)
-
-	if trace {
-		p.tracef("\n")
-	}
-
-	// --- end of export data ---
-
-	return p.out.Bytes(), nil
-}
-
-func (p *exporter) pkg(pkg *types.Package, emptypath bool) {
-	if pkg == nil {
-		panic(internalError("unexpected nil pkg"))
-	}
-
-	// if we saw the package before, write its index (>= 0)
-	if i, ok := p.pkgIndex[pkg]; ok {
-		p.index('P', i)
-		return
-	}
-
-	// otherwise, remember the package, write the package tag (< 0) and package data
-	if trace {
-		p.tracef("P%d = { ", len(p.pkgIndex))
-		defer p.tracef("} ")
-	}
-	p.pkgIndex[pkg] = len(p.pkgIndex)
-
-	p.tag(packageTag)
-	p.string(pkg.Name())
-	if emptypath {
-		p.string("")
-	} else {
-		p.string(pkg.Path())
-	}
-}
-
-func (p *exporter) obj(obj types.Object) {
-	switch obj := obj.(type) {
-	case *types.Const:
-		p.tag(constTag)
-		p.pos(obj)
-		p.qualifiedName(obj)
-		p.typ(obj.Type())
-		p.value(obj.Val())
-
-	case *types.TypeName:
-		if obj.IsAlias() {
-			p.tag(aliasTag)
-			p.pos(obj)
-			p.qualifiedName(obj)
-		} else {
-			p.tag(typeTag)
-		}
-		p.typ(obj.Type())
-
-	case *types.Var:
-		p.tag(varTag)
-		p.pos(obj)
-		p.qualifiedName(obj)
-		p.typ(obj.Type())
-
-	case *types.Func:
-		p.tag(funcTag)
-		p.pos(obj)
-		p.qualifiedName(obj)
-		sig := obj.Type().(*types.Signature)
-		p.paramList(sig.Params(), sig.Variadic())
-		p.paramList(sig.Results(), false)
-
-	default:
-		panic(internalErrorf("unexpected object %v (%T)", obj, obj))
-	}
-}
-
-func (p *exporter) pos(obj types.Object) {
-	if !p.posInfoFormat {
-		return
-	}
-
-	file, line := p.fileLine(obj)
-	if file == p.prevFile {
-		// common case: write line delta
-		// delta == 0 means different file or no line change
-		delta := line - p.prevLine
-		p.int(delta)
-		if delta == 0 {
-			p.int(-1) // -1 means no file change
-		}
-	} else {
-		// different file
-		p.int(0)
-		// Encode filename as length of common prefix with previous
-		// filename, followed by (possibly empty) suffix. Filenames
-		// frequently share path prefixes, so this can save a lot
-		// of space and make export data size less dependent on file
-		// path length. The suffix is unlikely to be empty because
-		// file names tend to end in ".go".
-		n := commonPrefixLen(p.prevFile, file)
-		p.int(n)           // n >= 0
-		p.string(file[n:]) // write suffix only
-		p.prevFile = file
-		p.int(line)
-	}
-	p.prevLine = line
-}
-
-func (p *exporter) fileLine(obj types.Object) (file string, line int) {
-	if p.fset != nil {
-		pos := p.fset.Position(obj.Pos())
-		file = pos.Filename
-		line = pos.Line
-	}
-	return
-}
-
-func commonPrefixLen(a, b string) int {
-	if len(a) > len(b) {
-		a, b = b, a
-	}
-	// len(a) <= len(b)
-	i := 0
-	for i < len(a) && a[i] == b[i] {
-		i++
-	}
-	return i
-}
-
-func (p *exporter) qualifiedName(obj types.Object) {
-	p.string(obj.Name())
-	p.pkg(obj.Pkg(), false)
-}
-
-func (p *exporter) typ(t types.Type) {
-	if t == nil {
-		panic(internalError("nil type"))
-	}
-
-	// Possible optimization: Anonymous pointer types *T where
-	// T is a named type are common. We could canonicalize all
-	// such types *T to a single type PT = *T. This would lead
-	// to at most one *T entry in typIndex, and all future *T's
-	// would be encoded as the respective index directly. Would
-	// save 1 byte (pointerTag) per *T and reduce the typIndex
-	// size (at the cost of a canonicalization map). We can do
-	// this later, without encoding format change.
-
-	// if we saw the type before, write its index (>= 0)
-	if i, ok := p.typIndex[t]; ok {
-		p.index('T', i)
-		return
-	}
-
-	// otherwise, remember the type, write the type tag (< 0) and type data
-	if trackAllTypes {
-		if trace {
-			p.tracef("T%d = {>\n", len(p.typIndex))
-			defer p.tracef("<\n} ")
-		}
-		p.typIndex[t] = len(p.typIndex)
-	}
-
-	switch t := t.(type) {
-	case *types.Named:
-		if !trackAllTypes {
-			// if we don't track all types, track named types now
-			p.typIndex[t] = len(p.typIndex)
-		}
-
-		p.tag(namedTag)
-		p.pos(t.Obj())
-		p.qualifiedName(t.Obj())
-		p.typ(t.Underlying())
-		if !types.IsInterface(t) {
-			p.assocMethods(t)
-		}
-
-	case *types.Array:
-		p.tag(arrayTag)
-		p.int64(t.Len())
-		p.typ(t.Elem())
-
-	case *types.Slice:
-		p.tag(sliceTag)
-		p.typ(t.Elem())
-
-	case *dddSlice:
-		p.tag(dddTag)
-		p.typ(t.elem)
-
-	case *types.Struct:
-		p.tag(structTag)
-		p.fieldList(t)
-
-	case *types.Pointer:
-		p.tag(pointerTag)
-		p.typ(t.Elem())
-
-	case *types.Signature:
-		p.tag(signatureTag)
-		p.paramList(t.Params(), t.Variadic())
-		p.paramList(t.Results(), false)
-
-	case *types.Interface:
-		p.tag(interfaceTag)
-		p.iface(t)
-
-	case *types.Map:
-		p.tag(mapTag)
-		p.typ(t.Key())
-		p.typ(t.Elem())
-
-	case *types.Chan:
-		p.tag(chanTag)
-		p.int(int(3 - t.Dir())) // hack
-		p.typ(t.Elem())
-
-	default:
-		panic(internalErrorf("unexpected type %T: %s", t, t))
-	}
-}
-
-func (p *exporter) assocMethods(named *types.Named) {
-	// Sort methods (for determinism).
-	var methods []*types.Func
-	for i := 0; i < named.NumMethods(); i++ {
-		methods = append(methods, named.Method(i))
-	}
-	sort.Sort(methodsByName(methods))
-
-	p.int(len(methods))
-
-	if trace && methods != nil {
-		p.tracef("associated methods {>\n")
-	}
-
-	for i, m := range methods {
-		if trace && i > 0 {
-			p.tracef("\n")
-		}
-
-		p.pos(m)
-		name := m.Name()
-		p.string(name)
-		if !exported(name) {
-			p.pkg(m.Pkg(), false)
-		}
-
-		sig := m.Type().(*types.Signature)
-		p.paramList(types.NewTuple(sig.Recv()), false)
-		p.paramList(sig.Params(), sig.Variadic())
-		p.paramList(sig.Results(), false)
-		p.int(0) // dummy value for go:nointerface pragma - ignored by importer
-	}
-
-	if trace && methods != nil {
-		p.tracef("<\n} ")
-	}
-}
-
-type methodsByName []*types.Func
-
-func (x methodsByName) Len() int           { return len(x) }
-func (x methodsByName) Swap(i, j int)      { x[i], x[j] = x[j], x[i] }
-func (x methodsByName) Less(i, j int) bool { return x[i].Name() < x[j].Name() }
-
-func (p *exporter) fieldList(t *types.Struct) {
-	if trace && t.NumFields() > 0 {
-		p.tracef("fields {>\n")
-		defer p.tracef("<\n} ")
-	}
-
-	p.int(t.NumFields())
-	for i := 0; i < t.NumFields(); i++ {
-		if trace && i > 0 {
-			p.tracef("\n")
-		}
-		p.field(t.Field(i))
-		p.string(t.Tag(i))
-	}
-}
-
-func (p *exporter) field(f *types.Var) {
-	if !f.IsField() {
-		panic(internalError("field expected"))
-	}
-
-	p.pos(f)
-	p.fieldName(f)
-	p.typ(f.Type())
-}
-
-func (p *exporter) iface(t *types.Interface) {
-	// TODO(gri): enable importer to load embedded interfaces,
-	// then emit Embeddeds and ExplicitMethods separately here.
-	p.int(0)
-
-	n := t.NumMethods()
-	if trace && n > 0 {
-		p.tracef("methods {>\n")
-		defer p.tracef("<\n} ")
-	}
-	p.int(n)
-	for i := 0; i < n; i++ {
-		if trace && i > 0 {
-			p.tracef("\n")
-		}
-		p.method(t.Method(i))
-	}
-}
-
-func (p *exporter) method(m *types.Func) {
-	sig := m.Type().(*types.Signature)
-	if sig.Recv() == nil {
-		panic(internalError("method expected"))
-	}
-
-	p.pos(m)
-	p.string(m.Name())
-	if m.Name() != "_" && !ast.IsExported(m.Name()) {
-		p.pkg(m.Pkg(), false)
-	}
-
-	// interface method; no need to encode receiver.
-	p.paramList(sig.Params(), sig.Variadic())
-	p.paramList(sig.Results(), false)
-}
-
-func (p *exporter) fieldName(f *types.Var) {
-	name := f.Name()
-
-	if f.Anonymous() {
-		// anonymous field - we distinguish between 3 cases:
-		// 1) field name matches base type name and is exported
-		// 2) field name matches base type name and is not exported
-		// 3) field name doesn't match base type name (alias name)
-		bname := basetypeName(f.Type())
-		if name == bname {
-			if ast.IsExported(name) {
-				name = "" // 1) we don't need to know the field name or package
-			} else {
-				name = "?" // 2) use unexported name "?" to force package export
-			}
-		} else {
-			// 3) indicate alias and export name as is
-			// (this requires an extra "@" but this is a rare case)
-			p.string("@")
-		}
-	}
-
-	p.string(name)
-	if name != "" && !ast.IsExported(name) {
-		p.pkg(f.Pkg(), false)
-	}
-}
-
-func basetypeName(typ types.Type) string {
-	switch typ := deref(typ).(type) {
-	case *types.Basic:
-		return typ.Name()
-	case *types.Named:
-		return typ.Obj().Name()
-	default:
-		return "" // unnamed type
-	}
-}
-
-func (p *exporter) paramList(params *types.Tuple, variadic bool) {
-	// use negative length to indicate unnamed parameters
-	// (look at the first parameter only since either all
-	// names are present or all are absent)
-	n := params.Len()
-	if n > 0 && params.At(0).Name() == "" {
-		n = -n
-	}
-	p.int(n)
-	for i := 0; i < params.Len(); i++ {
-		q := params.At(i)
-		t := q.Type()
-		if variadic && i == params.Len()-1 {
-			t = &dddSlice{t.(*types.Slice).Elem()}
-		}
-		p.typ(t)
-		if n > 0 {
-			name := q.Name()
-			p.string(name)
-			if name != "_" {
-				p.pkg(q.Pkg(), false)
-			}
-		}
-		p.string("") // no compiler-specific info
-	}
-}
-
-func (p *exporter) value(x constant.Value) {
-	if trace {
-		p.tracef("= ")
-	}
-
-	switch x.Kind() {
-	case constant.Bool:
-		tag := falseTag
-		if constant.BoolVal(x) {
-			tag = trueTag
-		}
-		p.tag(tag)
-
-	case constant.Int:
-		if v, exact := constant.Int64Val(x); exact {
-			// common case: x fits into an int64 - use compact encoding
-			p.tag(int64Tag)
-			p.int64(v)
-			return
-		}
-		// uncommon case: large x - use float encoding
-		// (powers of 2 will be encoded efficiently with exponent)
-		p.tag(floatTag)
-		p.float(constant.ToFloat(x))
-
-	case constant.Float:
-		p.tag(floatTag)
-		p.float(x)
-
-	case constant.Complex:
-		p.tag(complexTag)
-		p.float(constant.Real(x))
-		p.float(constant.Imag(x))
-
-	case constant.String:
-		p.tag(stringTag)
-		p.string(constant.StringVal(x))
-
-	case constant.Unknown:
-		// package contains type errors
-		p.tag(unknownTag)
-
-	default:
-		panic(internalErrorf("unexpected value %v (%T)", x, x))
-	}
-}
-
-func (p *exporter) float(x constant.Value) {
-	if x.Kind() != constant.Float {
-		panic(internalErrorf("unexpected constant %v, want float", x))
-	}
-	// extract sign (there is no -0)
-	sign := constant.Sign(x)
-	if sign == 0 {
-		// x == 0
-		p.int(0)
-		return
-	}
-	// x != 0
-
-	var f big.Float
-	if v, exact := constant.Float64Val(x); exact {
-		// float64
-		f.SetFloat64(v)
-	} else if num, denom := constant.Num(x), constant.Denom(x); num.Kind() == constant.Int {
-		// TODO(gri): add big.Rat accessor to constant.Value.
-		r := valueToRat(num)
-		f.SetRat(r.Quo(r, valueToRat(denom)))
-	} else {
-		// Value too large to represent as a fraction => inaccessible.
-		// TODO(gri): add big.Float accessor to constant.Value.
-		f.SetFloat64(math.MaxFloat64) // FIXME
-	}
-
-	// extract exponent such that 0.5 <= m < 1.0
-	var m big.Float
-	exp := f.MantExp(&m)
-
-	// extract mantissa as *big.Int
-	// - set exponent large enough so mant satisfies mant.IsInt()
-	// - get *big.Int from mant
-	m.SetMantExp(&m, int(m.MinPrec()))
-	mant, acc := m.Int(nil)
-	if acc != big.Exact {
-		panic(internalError("internal error"))
-	}
-
-	p.int(sign)
-	p.int(exp)
-	p.string(string(mant.Bytes()))
-}
-
-func valueToRat(x constant.Value) *big.Rat {
-	// Convert little-endian to big-endian.
-	// I can't believe this is necessary.
-	bytes := constant.Bytes(x)
-	for i := 0; i < len(bytes)/2; i++ {
-		bytes[i], bytes[len(bytes)-1-i] = bytes[len(bytes)-1-i], bytes[i]
-	}
-	return new(big.Rat).SetInt(new(big.Int).SetBytes(bytes))
-}
-
-func (p *exporter) bool(b bool) bool {
-	if trace {
-		p.tracef("[")
-		defer p.tracef("= %v] ", b)
-	}
-
-	x := 0
-	if b {
-		x = 1
-	}
-	p.int(x)
-	return b
-}
-
-// ----------------------------------------------------------------------------
-// Low-level encoders
-
-func (p *exporter) index(marker byte, index int) {
-	if index < 0 {
-		panic(internalError("invalid index < 0"))
-	}
-	if debugFormat {
-		p.marker('t')
-	}
-	if trace {
-		p.tracef("%c%d ", marker, index)
-	}
-	p.rawInt64(int64(index))
-}
-
-func (p *exporter) tag(tag int) {
-	if tag >= 0 {
-		panic(internalError("invalid tag >= 0"))
-	}
-	if debugFormat {
-		p.marker('t')
-	}
-	if trace {
-		p.tracef("%s ", tagString[-tag])
-	}
-	p.rawInt64(int64(tag))
-}
-
-func (p *exporter) int(x int) {
-	p.int64(int64(x))
-}
-
-func (p *exporter) int64(x int64) {
-	if debugFormat {
-		p.marker('i')
-	}
-	if trace {
-		p.tracef("%d ", x)
-	}
-	p.rawInt64(x)
-}
-
-func (p *exporter) string(s string) {
-	if debugFormat {
-		p.marker('s')
-	}
-	if trace {
-		p.tracef("%q ", s)
-	}
-	// if we saw the string before, write its index (>= 0)
-	// (the empty string is mapped to 0)
-	if i, ok := p.strIndex[s]; ok {
-		p.rawInt64(int64(i))
-		return
-	}
-	// otherwise, remember string and write its negative length and bytes
-	p.strIndex[s] = len(p.strIndex)
-	p.rawInt64(-int64(len(s)))
-	for i := 0; i < len(s); i++ {
-		p.rawByte(s[i])
-	}
-}
-
-// marker emits a marker byte and position information which makes
-// it easy for a reader to detect if it is "out of sync". Used for
-// debugFormat format only.
-func (p *exporter) marker(m byte) {
-	p.rawByte(m)
-	// Enable this for help tracking down the location
-	// of an incorrect marker when running in debugFormat.
-	if false && trace {
-		p.tracef("#%d ", p.written)
-	}
-	p.rawInt64(int64(p.written))
-}
-
-// rawInt64 should only be used by low-level encoders.
-func (p *exporter) rawInt64(x int64) {
-	var tmp [binary.MaxVarintLen64]byte
-	n := binary.PutVarint(tmp[:], x)
-	for i := 0; i < n; i++ {
-		p.rawByte(tmp[i])
-	}
-}
-
-// rawStringln should only be used to emit the initial version string.
-func (p *exporter) rawStringln(s string) {
-	for i := 0; i < len(s); i++ {
-		p.rawByte(s[i])
-	}
-	p.rawByte('\n')
-}
-
-// rawByte is the bottleneck interface to write to p.out.
-// rawByte escapes b as follows (any encoding does that
-// hides '$'):
-//
-//	'$'  => '|' 'S'
-//	'|'  => '|' '|'
-//
-// Necessary so other tools can find the end of the
-// export data by searching for "$$".
-// rawByte should only be used by low-level encoders.
-func (p *exporter) rawByte(b byte) {
-	switch b {
-	case '$':
-		// write '$' as '|' 'S'
-		b = 'S'
-		fallthrough
-	case '|':
-		// write '|' as '|' '|'
-		p.out.WriteByte('|')
-		p.written++
-	}
-	p.out.WriteByte(b)
-	p.written++
-}
-
-// tracef is like fmt.Printf but it rewrites the format string
-// to take care of indentation.
-func (p *exporter) tracef(format string, args ...interface{}) {
-	if strings.ContainsAny(format, "<>\n") {
-		var buf bytes.Buffer
-		for i := 0; i < len(format); i++ {
-			// no need to deal with runes
-			ch := format[i]
-			switch ch {
-			case '>':
-				p.indent++
-				continue
-			case '<':
-				p.indent--
-				continue
-			}
-			buf.WriteByte(ch)
-			if ch == '\n' {
-				for j := p.indent; j > 0; j-- {
-					buf.WriteString(".  ")
-				}
-			}
-		}
-		format = buf.String()
-	}
-	fmt.Printf(format, args...)
-}
-
-// Debugging support.
-// (tagString is only used when tracing is enabled)
-var tagString = [...]string{
-	// Packages
-	-packageTag: "package",
-
-	// Types
-	-namedTag:     "named type",
-	-arrayTag:     "array",
-	-sliceTag:     "slice",
-	-dddTag:       "ddd",
-	-structTag:    "struct",
-	-pointerTag:   "pointer",
-	-signatureTag: "signature",
-	-interfaceTag: "interface",
-	-mapTag:       "map",
-	-chanTag:      "chan",
-
-	// Values
-	-falseTag:    "false",
-	-trueTag:     "true",
-	-int64Tag:    "int64",
-	-floatTag:    "float",
-	-fractionTag: "fraction",
-	-complexTag:  "complex",
-	-stringTag:   "string",
-	-unknownTag:  "unknown",
-
-	// Type aliases
-	-aliasTag: "alias",
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/bimport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/bimport.go
deleted file mode 100644
index b85de01..0000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/bimport.go
+++ /dev/null
@@ -1,1053 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file is a copy of $GOROOT/src/go/internal/gcimporter/bimport.go.
-
-package gcimporter
-
-import (
-	"encoding/binary"
-	"fmt"
-	"go/constant"
-	"go/token"
-	"go/types"
-	"sort"
-	"strconv"
-	"strings"
-	"sync"
-	"unicode"
-	"unicode/utf8"
-)
-
-type importer struct {
-	imports    map[string]*types.Package
-	data       []byte
-	importpath string
-	buf        []byte // for reading strings
-	version    int    // export format version
-
-	// object lists
-	strList       []string           // in order of appearance
-	pathList      []string           // in order of appearance
-	pkgList       []*types.Package   // in order of appearance
-	typList       []types.Type       // in order of appearance
-	interfaceList []*types.Interface // for delayed completion only
-	trackAllTypes bool
-
-	// position encoding
-	posInfoFormat bool
-	prevFile      string
-	prevLine      int
-	fake          fakeFileSet
-
-	// debugging support
-	debugFormat bool
-	read        int // bytes read
-}
-
-// BImportData imports a package from the serialized package data
-// and returns the number of bytes consumed and a reference to the package.
-// If the export data version is not recognized or the format is otherwise
-// compromised, an error is returned.
-func BImportData(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string) (_ int, pkg *types.Package, err error) {
-	// catch panics and return them as errors
-	const currentVersion = 6
-	version := -1 // unknown version
-	defer func() {
-		if e := recover(); e != nil {
-			// Return a (possibly nil or incomplete) package unchanged (see #16088).
-			if version > currentVersion {
-				err = fmt.Errorf("cannot import %q (%v), export data is newer version - update tool", path, e)
-			} else {
-				err = fmt.Errorf("cannot import %q (%v), possibly version skew - reinstall package", path, e)
-			}
-		}
-	}()
-
-	p := importer{
-		imports:    imports,
-		data:       data,
-		importpath: path,
-		version:    version,
-		strList:    []string{""}, // empty string is mapped to 0
-		pathList:   []string{""}, // empty string is mapped to 0
-		fake: fakeFileSet{
-			fset:  fset,
-			files: make(map[string]*fileInfo),
-		},
-	}
-	defer p.fake.setLines() // set lines for files in fset
-
-	// read version info
-	var versionstr string
-	if b := p.rawByte(); b == 'c' || b == 'd' {
-		// Go1.7 encoding; first byte encodes low-level
-		// encoding format (compact vs debug).
-		// For backward-compatibility only (avoid problems with
-		// old installed packages). Newly compiled packages use
-		// the extensible format string.
-		// TODO(gri) Remove this support eventually; after Go1.8.
-		if b == 'd' {
-			p.debugFormat = true
-		}
-		p.trackAllTypes = p.rawByte() == 'a'
-		p.posInfoFormat = p.int() != 0
-		versionstr = p.string()
-		if versionstr == "v1" {
-			version = 0
-		}
-	} else {
-		// Go1.8 extensible encoding
-		// read version string and extract version number (ignore anything after the version number)
-		versionstr = p.rawStringln(b)
-		if s := strings.SplitN(versionstr, " ", 3); len(s) >= 2 && s[0] == "version" {
-			if v, err := strconv.Atoi(s[1]); err == nil && v > 0 {
-				version = v
-			}
-		}
-	}
-	p.version = version
-
-	// read version specific flags - extend as necessary
-	switch p.version {
-	// case currentVersion:
-	// 	...
-	//	fallthrough
-	case currentVersion, 5, 4, 3, 2, 1:
-		p.debugFormat = p.rawStringln(p.rawByte()) == "debug"
-		p.trackAllTypes = p.int() != 0
-		p.posInfoFormat = p.int() != 0
-	case 0:
-		// Go1.7 encoding format - nothing to do here
-	default:
-		errorf("unknown bexport format version %d (%q)", p.version, versionstr)
-	}
-
-	// --- generic export data ---
-
-	// populate typList with predeclared "known" types
-	p.typList = append(p.typList, predeclared()...)
-
-	// read package data
-	pkg = p.pkg()
-
-	// read objects of phase 1 only (see cmd/compile/internal/gc/bexport.go)
-	objcount := 0
-	for {
-		tag := p.tagOrIndex()
-		if tag == endTag {
-			break
-		}
-		p.obj(tag)
-		objcount++
-	}
-
-	// self-verification
-	if count := p.int(); count != objcount {
-		errorf("got %d objects; want %d", objcount, count)
-	}
-
-	// ignore compiler-specific import data
-
-	// complete interfaces
-	// TODO(gri) re-investigate if we still need to do this in a delayed fashion
-	for _, typ := range p.interfaceList {
-		typ.Complete()
-	}
-
-	// record all referenced packages as imports
-	list := append(([]*types.Package)(nil), p.pkgList[1:]...)
-	sort.Sort(byPath(list))
-	pkg.SetImports(list)
-
-	// package was imported completely and without errors
-	pkg.MarkComplete()
-
-	return p.read, pkg, nil
-}
-
-func errorf(format string, args ...interface{}) {
-	panic(fmt.Sprintf(format, args...))
-}
-
-func (p *importer) pkg() *types.Package {
-	// if the package was seen before, i is its index (>= 0)
-	i := p.tagOrIndex()
-	if i >= 0 {
-		return p.pkgList[i]
-	}
-
-	// otherwise, i is the package tag (< 0)
-	if i != packageTag {
-		errorf("unexpected package tag %d version %d", i, p.version)
-	}
-
-	// read package data
-	name := p.string()
-	var path string
-	if p.version >= 5 {
-		path = p.path()
-	} else {
-		path = p.string()
-	}
-	if p.version >= 6 {
-		p.int() // package height; unused by go/types
-	}
-
-	// we should never see an empty package name
-	if name == "" {
-		errorf("empty package name in import")
-	}
-
-	// an empty path denotes the package we are currently importing;
-	// it must be the first package we see
-	if (path == "") != (len(p.pkgList) == 0) {
-		errorf("package path %q for pkg index %d", path, len(p.pkgList))
-	}
-
-	// if the package was imported before, use that one; otherwise create a new one
-	if path == "" {
-		path = p.importpath
-	}
-	pkg := p.imports[path]
-	if pkg == nil {
-		pkg = types.NewPackage(path, name)
-		p.imports[path] = pkg
-	} else if pkg.Name() != name {
-		errorf("conflicting names %s and %s for package %q", pkg.Name(), name, path)
-	}
-	p.pkgList = append(p.pkgList, pkg)
-
-	return pkg
-}
-
-// objTag returns the tag value for each object kind.
-func objTag(obj types.Object) int {
-	switch obj.(type) {
-	case *types.Const:
-		return constTag
-	case *types.TypeName:
-		return typeTag
-	case *types.Var:
-		return varTag
-	case *types.Func:
-		return funcTag
-	default:
-		errorf("unexpected object: %v (%T)", obj, obj) // panics
-		panic("unreachable")
-	}
-}
-
-func sameObj(a, b types.Object) bool {
-	// Because unnamed types are not canonicalized, we cannot simply compare types for
-	// (pointer) identity.
-	// Ideally we'd check equality of constant values as well, but this is good enough.
-	return objTag(a) == objTag(b) && types.Identical(a.Type(), b.Type())
-}
-
-func (p *importer) declare(obj types.Object) {
-	pkg := obj.Pkg()
-	if alt := pkg.Scope().Insert(obj); alt != nil {
-		// This can only trigger if we import a (non-type) object a second time.
-		// Excluding type aliases, this cannot happen because 1) we only import a package
-		// once; and b) we ignore compiler-specific export data which may contain
-		// functions whose inlined function bodies refer to other functions that
-		// were already imported.
-		// However, type aliases require reexporting the original type, so we need
-		// to allow it (see also the comment in cmd/compile/internal/gc/bimport.go,
-		// method importer.obj, switch case importing functions).
-		// TODO(gri) review/update this comment once the gc compiler handles type aliases.
-		if !sameObj(obj, alt) {
-			errorf("inconsistent import:\n\t%v\npreviously imported as:\n\t%v\n", obj, alt)
-		}
-	}
-}
-
-func (p *importer) obj(tag int) {
-	switch tag {
-	case constTag:
-		pos := p.pos()
-		pkg, name := p.qualifiedName()
-		typ := p.typ(nil, nil)
-		val := p.value()
-		p.declare(types.NewConst(pos, pkg, name, typ, val))
-
-	case aliasTag:
-		// TODO(gri) verify type alias hookup is correct
-		pos := p.pos()
-		pkg, name := p.qualifiedName()
-		typ := p.typ(nil, nil)
-		p.declare(types.NewTypeName(pos, pkg, name, typ))
-
-	case typeTag:
-		p.typ(nil, nil)
-
-	case varTag:
-		pos := p.pos()
-		pkg, name := p.qualifiedName()
-		typ := p.typ(nil, nil)
-		p.declare(types.NewVar(pos, pkg, name, typ))
-
-	case funcTag:
-		pos := p.pos()
-		pkg, name := p.qualifiedName()
-		params, isddd := p.paramList()
-		result, _ := p.paramList()
-		sig := types.NewSignature(nil, params, result, isddd)
-		p.declare(types.NewFunc(pos, pkg, name, sig))
-
-	default:
-		errorf("unexpected object tag %d", tag)
-	}
-}
-
-const deltaNewFile = -64 // see cmd/compile/internal/gc/bexport.go
-
-func (p *importer) pos() token.Pos {
-	if !p.posInfoFormat {
-		return token.NoPos
-	}
-
-	file := p.prevFile
-	line := p.prevLine
-	delta := p.int()
-	line += delta
-	if p.version >= 5 {
-		if delta == deltaNewFile {
-			if n := p.int(); n >= 0 {
-				// file changed
-				file = p.path()
-				line = n
-			}
-		}
-	} else {
-		if delta == 0 {
-			if n := p.int(); n >= 0 {
-				// file changed
-				file = p.prevFile[:n] + p.string()
-				line = p.int()
-			}
-		}
-	}
-	p.prevFile = file
-	p.prevLine = line
-
-	return p.fake.pos(file, line, 0)
-}
-
-// Synthesize a token.Pos
-type fakeFileSet struct {
-	fset  *token.FileSet
-	files map[string]*fileInfo
-}
-
-type fileInfo struct {
-	file     *token.File
-	lastline int
-}
-
-const maxlines = 64 * 1024
-
-func (s *fakeFileSet) pos(file string, line, column int) token.Pos {
-	// TODO(mdempsky): Make use of column.
-
-	// Since we don't know the set of needed file positions, we reserve maxlines
-	// positions per file. We delay calling token.File.SetLines until all
-	// positions have been calculated (by way of fakeFileSet.setLines), so that
-	// we can avoid setting unnecessary lines. See also golang/go#46586.
-	f := s.files[file]
-	if f == nil {
-		f = &fileInfo{file: s.fset.AddFile(file, -1, maxlines)}
-		s.files[file] = f
-	}
-	if line > maxlines {
-		line = 1
-	}
-	if line > f.lastline {
-		f.lastline = line
-	}
-
-	// Return a fake position assuming that f.file consists only of newlines.
-	return token.Pos(f.file.Base() + line - 1)
-}
-
-func (s *fakeFileSet) setLines() {
-	fakeLinesOnce.Do(func() {
-		fakeLines = make([]int, maxlines)
-		for i := range fakeLines {
-			fakeLines[i] = i
-		}
-	})
-	for _, f := range s.files {
-		f.file.SetLines(fakeLines[:f.lastline])
-	}
-}
-
-var (
-	fakeLines     []int
-	fakeLinesOnce sync.Once
-)
-
-func (p *importer) qualifiedName() (pkg *types.Package, name string) {
-	name = p.string()
-	pkg = p.pkg()
-	return
-}
-
-func (p *importer) record(t types.Type) {
-	p.typList = append(p.typList, t)
-}
-
-// A dddSlice is a types.Type representing ...T parameters.
-// It only appears for parameter types and does not escape
-// the importer.
-type dddSlice struct {
-	elem types.Type
-}
-
-func (t *dddSlice) Underlying() types.Type { return t }
-func (t *dddSlice) String() string         { return "..." + t.elem.String() }
-
-// parent is the package which declared the type; parent == nil means
-// the package currently imported. The parent package is needed for
-// exported struct fields and interface methods which don't contain
-// explicit package information in the export data.
-//
-// A non-nil tname is used as the "owner" of the result type; i.e.,
-// the result type is the underlying type of tname. tname is used
-// to give interface methods a named receiver type where possible.
-func (p *importer) typ(parent *types.Package, tname *types.Named) types.Type {
-	// if the type was seen before, i is its index (>= 0)
-	i := p.tagOrIndex()
-	if i >= 0 {
-		return p.typList[i]
-	}
-
-	// otherwise, i is the type tag (< 0)
-	switch i {
-	case namedTag:
-		// read type object
-		pos := p.pos()
-		parent, name := p.qualifiedName()
-		scope := parent.Scope()
-		obj := scope.Lookup(name)
-
-		// if the object doesn't exist yet, create and insert it
-		if obj == nil {
-			obj = types.NewTypeName(pos, parent, name, nil)
-			scope.Insert(obj)
-		}
-
-		if _, ok := obj.(*types.TypeName); !ok {
-			errorf("pkg = %s, name = %s => %s", parent, name, obj)
-		}
-
-		// associate new named type with obj if it doesn't exist yet
-		t0 := types.NewNamed(obj.(*types.TypeName), nil, nil)
-
-		// but record the existing type, if any
-		tname := obj.Type().(*types.Named) // tname is either t0 or the existing type
-		p.record(tname)
-
-		// read underlying type
-		t0.SetUnderlying(p.typ(parent, t0))
-
-		// interfaces don't have associated methods
-		if types.IsInterface(t0) {
-			return tname
-		}
-
-		// read associated methods
-		for i := p.int(); i > 0; i-- {
-			// TODO(gri) replace this with something closer to fieldName
-			pos := p.pos()
-			name := p.string()
-			if !exported(name) {
-				p.pkg()
-			}
-
-			recv, _ := p.paramList() // TODO(gri) do we need a full param list for the receiver?
-			params, isddd := p.paramList()
-			result, _ := p.paramList()
-			p.int() // go:nointerface pragma - discarded
-
-			sig := types.NewSignature(recv.At(0), params, result, isddd)
-			t0.AddMethod(types.NewFunc(pos, parent, name, sig))
-		}
-
-		return tname
-
-	case arrayTag:
-		t := new(types.Array)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		n := p.int64()
-		*t = *types.NewArray(p.typ(parent, nil), n)
-		return t
-
-	case sliceTag:
-		t := new(types.Slice)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		*t = *types.NewSlice(p.typ(parent, nil))
-		return t
-
-	case dddTag:
-		t := new(dddSlice)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		t.elem = p.typ(parent, nil)
-		return t
-
-	case structTag:
-		t := new(types.Struct)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		*t = *types.NewStruct(p.fieldList(parent))
-		return t
-
-	case pointerTag:
-		t := new(types.Pointer)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		*t = *types.NewPointer(p.typ(parent, nil))
-		return t
-
-	case signatureTag:
-		t := new(types.Signature)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		params, isddd := p.paramList()
-		result, _ := p.paramList()
-		*t = *types.NewSignature(nil, params, result, isddd)
-		return t
-
-	case interfaceTag:
-		// Create a dummy entry in the type list. This is safe because we
-		// cannot expect the interface type to appear in a cycle, as any
-		// such cycle must contain a named type which would have been
-		// first defined earlier.
-		// TODO(gri) Is this still true now that we have type aliases?
-		// See issue #23225.
-		n := len(p.typList)
-		if p.trackAllTypes {
-			p.record(nil)
-		}
-
-		var embeddeds []types.Type
-		for n := p.int(); n > 0; n-- {
-			p.pos()
-			embeddeds = append(embeddeds, p.typ(parent, nil))
-		}
-
-		t := newInterface(p.methodList(parent, tname), embeddeds)
-		p.interfaceList = append(p.interfaceList, t)
-		if p.trackAllTypes {
-			p.typList[n] = t
-		}
-		return t
-
-	case mapTag:
-		t := new(types.Map)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		key := p.typ(parent, nil)
-		val := p.typ(parent, nil)
-		*t = *types.NewMap(key, val)
-		return t
-
-	case chanTag:
-		t := new(types.Chan)
-		if p.trackAllTypes {
-			p.record(t)
-		}
-
-		dir := chanDir(p.int())
-		val := p.typ(parent, nil)
-		*t = *types.NewChan(dir, val)
-		return t
-
-	default:
-		errorf("unexpected type tag %d", i) // panics
-		panic("unreachable")
-	}
-}
-
-func chanDir(d int) types.ChanDir {
-	// tag values must match the constants in cmd/compile/internal/gc/go.go
-	switch d {
-	case 1 /* Crecv */ :
-		return types.RecvOnly
-	case 2 /* Csend */ :
-		return types.SendOnly
-	case 3 /* Cboth */ :
-		return types.SendRecv
-	default:
-		errorf("unexpected channel dir %d", d)
-		return 0
-	}
-}
-
-func (p *importer) fieldList(parent *types.Package) (fields []*types.Var, tags []string) {
-	if n := p.int(); n > 0 {
-		fields = make([]*types.Var, n)
-		tags = make([]string, n)
-		for i := range fields {
-			fields[i], tags[i] = p.field(parent)
-		}
-	}
-	return
-}
-
-func (p *importer) field(parent *types.Package) (*types.Var, string) {
-	pos := p.pos()
-	pkg, name, alias := p.fieldName(parent)
-	typ := p.typ(parent, nil)
-	tag := p.string()
-
-	anonymous := false
-	if name == "" {
-		// anonymous field - typ must be T or *T and T must be a type name
-		switch typ := deref(typ).(type) {
-		case *types.Basic: // basic types are named types
-			pkg = nil // // objects defined in Universe scope have no package
-			name = typ.Name()
-		case *types.Named:
-			name = typ.Obj().Name()
-		default:
-			errorf("named base type expected")
-		}
-		anonymous = true
-	} else if alias {
-		// anonymous field: we have an explicit name because it's an alias
-		anonymous = true
-	}
-
-	return types.NewField(pos, pkg, name, typ, anonymous), tag
-}
-
-func (p *importer) methodList(parent *types.Package, baseType *types.Named) (methods []*types.Func) {
-	if n := p.int(); n > 0 {
-		methods = make([]*types.Func, n)
-		for i := range methods {
-			methods[i] = p.method(parent, baseType)
-		}
-	}
-	return
-}
-
-func (p *importer) method(parent *types.Package, baseType *types.Named) *types.Func {
-	pos := p.pos()
-	pkg, name, _ := p.fieldName(parent)
-	// If we don't have a baseType, use a nil receiver.
-	// A receiver using the actual interface type (which
-	// we don't know yet) will be filled in when we call
-	// types.Interface.Complete.
-	var recv *types.Var
-	if baseType != nil {
-		recv = types.NewVar(token.NoPos, parent, "", baseType)
-	}
-	params, isddd := p.paramList()
-	result, _ := p.paramList()
-	sig := types.NewSignature(recv, params, result, isddd)
-	return types.NewFunc(pos, pkg, name, sig)
-}
-
-func (p *importer) fieldName(parent *types.Package) (pkg *types.Package, name string, alias bool) {
-	name = p.string()
-	pkg = parent
-	if pkg == nil {
-		// use the imported package instead
-		pkg = p.pkgList[0]
-	}
-	if p.version == 0 && name == "_" {
-		// version 0 didn't export a package for _ fields
-		return
-	}
-	switch name {
-	case "":
-		// 1) field name matches base type name and is exported: nothing to do
-	case "?":
-		// 2) field name matches base type name and is not exported: need package
-		name = ""
-		pkg = p.pkg()
-	case "@":
-		// 3) field name doesn't match type name (alias)
-		name = p.string()
-		alias = true
-		fallthrough
-	default:
-		if !exported(name) {
-			pkg = p.pkg()
-		}
-	}
-	return
-}
-
-func (p *importer) paramList() (*types.Tuple, bool) {
-	n := p.int()
-	if n == 0 {
-		return nil, false
-	}
-	// negative length indicates unnamed parameters
-	named := true
-	if n < 0 {
-		n = -n
-		named = false
-	}
-	// n > 0
-	params := make([]*types.Var, n)
-	isddd := false
-	for i := range params {
-		params[i], isddd = p.param(named)
-	}
-	return types.NewTuple(params...), isddd
-}
-
-func (p *importer) param(named bool) (*types.Var, bool) {
-	t := p.typ(nil, nil)
-	td, isddd := t.(*dddSlice)
-	if isddd {
-		t = types.NewSlice(td.elem)
-	}
-
-	var pkg *types.Package
-	var name string
-	if named {
-		name = p.string()
-		if name == "" {
-			errorf("expected named parameter")
-		}
-		if name != "_" {
-			pkg = p.pkg()
-		}
-		if i := strings.Index(name, "·"); i > 0 {
-			name = name[:i] // cut off gc-specific parameter numbering
-		}
-	}
-
-	// read and discard compiler-specific info
-	p.string()
-
-	return types.NewVar(token.NoPos, pkg, name, t), isddd
-}
-
-func exported(name string) bool {
-	ch, _ := utf8.DecodeRuneInString(name)
-	return unicode.IsUpper(ch)
-}
-
-func (p *importer) value() constant.Value {
-	switch tag := p.tagOrIndex(); tag {
-	case falseTag:
-		return constant.MakeBool(false)
-	case trueTag:
-		return constant.MakeBool(true)
-	case int64Tag:
-		return constant.MakeInt64(p.int64())
-	case floatTag:
-		return p.float()
-	case complexTag:
-		re := p.float()
-		im := p.float()
-		return constant.BinaryOp(re, token.ADD, constant.MakeImag(im))
-	case stringTag:
-		return constant.MakeString(p.string())
-	case unknownTag:
-		return constant.MakeUnknown()
-	default:
-		errorf("unexpected value tag %d", tag) // panics
-		panic("unreachable")
-	}
-}
-
-func (p *importer) float() constant.Value {
-	sign := p.int()
-	if sign == 0 {
-		return constant.MakeInt64(0)
-	}
-
-	exp := p.int()
-	mant := []byte(p.string()) // big endian
-
-	// remove leading 0's if any
-	for len(mant) > 0 && mant[0] == 0 {
-		mant = mant[1:]
-	}
-
-	// convert to little endian
-	// TODO(gri) go/constant should have a more direct conversion function
-	//           (e.g., once it supports a big.Float based implementation)
-	for i, j := 0, len(mant)-1; i < j; i, j = i+1, j-1 {
-		mant[i], mant[j] = mant[j], mant[i]
-	}
-
-	// adjust exponent (constant.MakeFromBytes creates an integer value,
-	// but mant represents the mantissa bits such that 0.5 <= mant < 1.0)
-	exp -= len(mant) << 3
-	if len(mant) > 0 {
-		for msd := mant[len(mant)-1]; msd&0x80 == 0; msd <<= 1 {
-			exp++
-		}
-	}
-
-	x := constant.MakeFromBytes(mant)
-	switch {
-	case exp < 0:
-		d := constant.Shift(constant.MakeInt64(1), token.SHL, uint(-exp))
-		x = constant.BinaryOp(x, token.QUO, d)
-	case exp > 0:
-		x = constant.Shift(x, token.SHL, uint(exp))
-	}
-
-	if sign < 0 {
-		x = constant.UnaryOp(token.SUB, x, 0)
-	}
-	return x
-}
-
-// ----------------------------------------------------------------------------
-// Low-level decoders
-
-func (p *importer) tagOrIndex() int {
-	if p.debugFormat {
-		p.marker('t')
-	}
-
-	return int(p.rawInt64())
-}
-
-func (p *importer) int() int {
-	x := p.int64()
-	if int64(int(x)) != x {
-		errorf("exported integer too large")
-	}
-	return int(x)
-}
-
-func (p *importer) int64() int64 {
-	if p.debugFormat {
-		p.marker('i')
-	}
-
-	return p.rawInt64()
-}
-
-func (p *importer) path() string {
-	if p.debugFormat {
-		p.marker('p')
-	}
-	// if the path was seen before, i is its index (>= 0)
-	// (the empty string is at index 0)
-	i := p.rawInt64()
-	if i >= 0 {
-		return p.pathList[i]
-	}
-	// otherwise, i is the negative path length (< 0)
-	a := make([]string, -i)
-	for n := range a {
-		a[n] = p.string()
-	}
-	s := strings.Join(a, "/")
-	p.pathList = append(p.pathList, s)
-	return s
-}
-
-func (p *importer) string() string {
-	if p.debugFormat {
-		p.marker('s')
-	}
-	// if the string was seen before, i is its index (>= 0)
-	// (the empty string is at index 0)
-	i := p.rawInt64()
-	if i >= 0 {
-		return p.strList[i]
-	}
-	// otherwise, i is the negative string length (< 0)
-	if n := int(-i); n <= cap(p.buf) {
-		p.buf = p.buf[:n]
-	} else {
-		p.buf = make([]byte, n)
-	}
-	for i := range p.buf {
-		p.buf[i] = p.rawByte()
-	}
-	s := string(p.buf)
-	p.strList = append(p.strList, s)
-	return s
-}
-
-func (p *importer) marker(want byte) {
-	if got := p.rawByte(); got != want {
-		errorf("incorrect marker: got %c; want %c (pos = %d)", got, want, p.read)
-	}
-
-	pos := p.read
-	if n := int(p.rawInt64()); n != pos {
-		errorf("incorrect position: got %d; want %d", n, pos)
-	}
-}
-
-// rawInt64 should only be used by low-level decoders.
-func (p *importer) rawInt64() int64 {
-	i, err := binary.ReadVarint(p)
-	if err != nil {
-		errorf("read error: %v", err)
-	}
-	return i
-}
-
-// rawStringln should only be used to read the initial version string.
-func (p *importer) rawStringln(b byte) string {
-	p.buf = p.buf[:0]
-	for b != '\n' {
-		p.buf = append(p.buf, b)
-		b = p.rawByte()
-	}
-	return string(p.buf)
-}
-
-// needed for binary.ReadVarint in rawInt64
-func (p *importer) ReadByte() (byte, error) {
-	return p.rawByte(), nil
-}
-
-// byte is the bottleneck interface for reading p.data.
-// It unescapes '|' 'S' to '$' and '|' '|' to '|'.
-// rawByte should only be used by low-level decoders.
-func (p *importer) rawByte() byte {
-	b := p.data[0]
-	r := 1
-	if b == '|' {
-		b = p.data[1]
-		r = 2
-		switch b {
-		case 'S':
-			b = '$'
-		case '|':
-			// nothing to do
-		default:
-			errorf("unexpected escape sequence in export data")
-		}
-	}
-	p.data = p.data[r:]
-	p.read += r
-	return b
-
-}
-
-// ----------------------------------------------------------------------------
-// Export format
-
-// Tags. Must be < 0.
-const (
-	// Objects
-	packageTag = -(iota + 1)
-	constTag
-	typeTag
-	varTag
-	funcTag
-	endTag
-
-	// Types
-	namedTag
-	arrayTag
-	sliceTag
-	dddTag
-	structTag
-	pointerTag
-	signatureTag
-	interfaceTag
-	mapTag
-	chanTag
-
-	// Values
-	falseTag
-	trueTag
-	int64Tag
-	floatTag
-	fractionTag // not used by gc
-	complexTag
-	stringTag
-	nilTag     // only used by gc (appears in exported inlined function bodies)
-	unknownTag // not used by gc (only appears in packages with errors)
-
-	// Type aliases
-	aliasTag
-)
-
-var predeclOnce sync.Once
-var predecl []types.Type // initialized lazily
-
-func predeclared() []types.Type {
-	predeclOnce.Do(func() {
-		// initialize lazily to be sure that all
-		// elements have been initialized before
-		predecl = []types.Type{ // basic types
-			types.Typ[types.Bool],
-			types.Typ[types.Int],
-			types.Typ[types.Int8],
-			types.Typ[types.Int16],
-			types.Typ[types.Int32],
-			types.Typ[types.Int64],
-			types.Typ[types.Uint],
-			types.Typ[types.Uint8],
-			types.Typ[types.Uint16],
-			types.Typ[types.Uint32],
-			types.Typ[types.Uint64],
-			types.Typ[types.Uintptr],
-			types.Typ[types.Float32],
-			types.Typ[types.Float64],
-			types.Typ[types.Complex64],
-			types.Typ[types.Complex128],
-			types.Typ[types.String],
-
-			// basic type aliases
-			types.Universe.Lookup("byte").Type(),
-			types.Universe.Lookup("rune").Type(),
-
-			// error
-			types.Universe.Lookup("error").Type(),
-
-			// untyped types
-			types.Typ[types.UntypedBool],
-			types.Typ[types.UntypedInt],
-			types.Typ[types.UntypedRune],
-			types.Typ[types.UntypedFloat],
-			types.Typ[types.UntypedComplex],
-			types.Typ[types.UntypedString],
-			types.Typ[types.UntypedNil],
-
-			// package unsafe
-			types.Typ[types.UnsafePointer],
-
-			// invalid type
-			types.Typ[types.Invalid], // only appears in packages with errors
-
-			// used internally by gc; never used by this package or in .a files
-			anyType{},
-		}
-		predecl = append(predecl, additionalPredeclared()...)
-	})
-	return predecl
-}
-
-type anyType struct{}
-
-func (t anyType) Underlying() types.Type { return t }
-func (t anyType) String() string         { return "any" }
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/exportdata.go b/vendor/golang.org/x/tools/go/internal/gcimporter/exportdata.go
deleted file mode 100644
index f6437fe..0000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/exportdata.go
+++ /dev/null
@@ -1,99 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file is a copy of $GOROOT/src/go/internal/gcimporter/exportdata.go.
-
-// This file implements FindExportData.
-
-package gcimporter
-
-import (
-	"bufio"
-	"fmt"
-	"io"
-	"strconv"
-	"strings"
-)
-
-func readGopackHeader(r *bufio.Reader) (name string, size int64, err error) {
-	// See $GOROOT/include/ar.h.
-	hdr := make([]byte, 16+12+6+6+8+10+2)
-	_, err = io.ReadFull(r, hdr)
-	if err != nil {
-		return
-	}
-	// leave for debugging
-	if false {
-		fmt.Printf("header: %s", hdr)
-	}
-	s := strings.TrimSpace(string(hdr[16+12+6+6+8:][:10]))
-	length, err := strconv.Atoi(s)
-	size = int64(length)
-	if err != nil || hdr[len(hdr)-2] != '`' || hdr[len(hdr)-1] != '\n' {
-		err = fmt.Errorf("invalid archive header")
-		return
-	}
-	name = strings.TrimSpace(string(hdr[:16]))
-	return
-}
-
-// FindExportData positions the reader r at the beginning of the
-// export data section of an underlying GC-created object/archive
-// file by reading from it. The reader must be positioned at the
-// start of the file before calling this function. The hdr result
-// is the string before the export data, either "$$" or "$$B".
-// The size result is the length of the export data in bytes, or -1 if not known.
-func FindExportData(r *bufio.Reader) (hdr string, size int64, err error) {
-	// Read first line to make sure this is an object file.
-	line, err := r.ReadSlice('\n')
-	if err != nil {
-		err = fmt.Errorf("can't find export data (%v)", err)
-		return
-	}
-
-	if string(line) == "!<arch>\n" {
-		// Archive file. Scan to __.PKGDEF.
-		var name string
-		if name, size, err = readGopackHeader(r); err != nil {
-			return
-		}
-
-		// First entry should be __.PKGDEF.
-		if name != "__.PKGDEF" {
-			err = fmt.Errorf("go archive is missing __.PKGDEF")
-			return
-		}
-
-		// Read first line of __.PKGDEF data, so that line
-		// is once again the first line of the input.
-		if line, err = r.ReadSlice('\n'); err != nil {
-			err = fmt.Errorf("can't find export data (%v)", err)
-			return
-		}
-		size -= int64(len(line))
-	}
-
-	// Now at __.PKGDEF in archive or still at beginning of file.
-	// Either way, line should begin with "go object ".
-	if !strings.HasPrefix(string(line), "go object ") {
-		err = fmt.Errorf("not a Go object file")
-		return
-	}
-
-	// Skip over object header to export data.
-	// Begins after first line starting with $$.
-	for line[0] != '$' {
-		if line, err = r.ReadSlice('\n'); err != nil {
-			err = fmt.Errorf("can't find export data (%v)", err)
-			return
-		}
-		size -= int64(len(line))
-	}
-	hdr = string(line)
-	if size < 0 {
-		size = -1
-	}
-
-	return
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go b/vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go
deleted file mode 100644
index 3ab6683..0000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/gcimporter.go
+++ /dev/null
@@ -1,1084 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file is a modified copy of $GOROOT/src/go/internal/gcimporter/gcimporter.go,
-// but it also contains the original source-based importer code for Go1.6.
-// Once we stop supporting 1.6, we can remove that code.
-
-// Package gcimporter provides various functions for reading
-// gc-generated object files that can be used to implement the
-// Importer interface defined by the Go 1.5 standard library package.
-package gcimporter // import "golang.org/x/tools/go/internal/gcimporter"
-
-import (
-	"bufio"
-	"errors"
-	"fmt"
-	"go/build"
-	"go/constant"
-	"go/token"
-	"go/types"
-	"io"
-	"io/ioutil"
-	"os"
-	"path/filepath"
-	"sort"
-	"strconv"
-	"strings"
-	"text/scanner"
-)
-
-const (
-	// Enable debug during development: it adds some additional checks, and
-	// prevents errors from being recovered.
-	debug = false
-
-	// If trace is set, debugging output is printed to std out.
-	trace = false
-)
-
-var pkgExts = [...]string{".a", ".o"}
-
-// FindPkg returns the filename and unique package id for an import
-// path based on package information provided by build.Import (using
-// the build.Default build.Context). A relative srcDir is interpreted
-// relative to the current working directory.
-// If no file was found, an empty filename is returned.
-//
-func FindPkg(path, srcDir string) (filename, id string) {
-	if path == "" {
-		return
-	}
-
-	var noext string
-	switch {
-	default:
-		// "x" -> "$GOPATH/pkg/$GOOS_$GOARCH/x.ext", "x"
-		// Don't require the source files to be present.
-		if abs, err := filepath.Abs(srcDir); err == nil { // see issue 14282
-			srcDir = abs
-		}
-		bp, _ := build.Import(path, srcDir, build.FindOnly|build.AllowBinary)
-		if bp.PkgObj == "" {
-			id = path // make sure we have an id to print in error message
-			return
-		}
-		noext = strings.TrimSuffix(bp.PkgObj, ".a")
-		id = bp.ImportPath
-
-	case build.IsLocalImport(path):
-		// "./x" -> "/this/directory/x.ext", "/this/directory/x"
-		noext = filepath.Join(srcDir, path)
-		id = noext
-
-	case filepath.IsAbs(path):
-		// for completeness only - go/build.Import
-		// does not support absolute imports
-		// "/x" -> "/x.ext", "/x"
-		noext = path
-		id = path
-	}
-
-	if false { // for debugging
-		if path != id {
-			fmt.Printf("%s -> %s\n", path, id)
-		}
-	}
-
-	// try extensions
-	for _, ext := range pkgExts {
-		filename = noext + ext
-		if f, err := os.Stat(filename); err == nil && !f.IsDir() {
-			return
-		}
-	}
-
-	filename = "" // not found
-	return
-}
-
-// ImportData imports a package by reading the gc-generated export data,
-// adds the corresponding package object to the packages map indexed by id,
-// and returns the object.
-//
-// The packages map must contains all packages already imported. The data
-// reader position must be the beginning of the export data section. The
-// filename is only used in error messages.
-//
-// If packages[id] contains the completely imported package, that package
-// can be used directly, and there is no need to call this function (but
-// there is also no harm but for extra time used).
-//
-func ImportData(packages map[string]*types.Package, filename, id string, data io.Reader) (pkg *types.Package, err error) {
-	// support for parser error handling
-	defer func() {
-		switch r := recover().(type) {
-		case nil:
-			// nothing to do
-		case importError:
-			err = r
-		default:
-			panic(r) // internal error
-		}
-	}()
-
-	var p parser
-	p.init(filename, id, data, packages)
-	pkg = p.parseExport()
-
-	return
-}
-
-// Import imports a gc-generated package given its import path and srcDir, adds
-// the corresponding package object to the packages map, and returns the object.
-// The packages map must contain all packages already imported.
-//
-func Import(packages map[string]*types.Package, path, srcDir string, lookup func(path string) (io.ReadCloser, error)) (pkg *types.Package, err error) {
-	var rc io.ReadCloser
-	var filename, id string
-	if lookup != nil {
-		// With custom lookup specified, assume that caller has
-		// converted path to a canonical import path for use in the map.
-		if path == "unsafe" {
-			return types.Unsafe, nil
-		}
-		id = path
-
-		// No need to re-import if the package was imported completely before.
-		if pkg = packages[id]; pkg != nil && pkg.Complete() {
-			return
-		}
-		f, err := lookup(path)
-		if err != nil {
-			return nil, err
-		}
-		rc = f
-	} else {
-		filename, id = FindPkg(path, srcDir)
-		if filename == "" {
-			if path == "unsafe" {
-				return types.Unsafe, nil
-			}
-			return nil, fmt.Errorf("can't find import: %q", id)
-		}
-
-		// no need to re-import if the package was imported completely before
-		if pkg = packages[id]; pkg != nil && pkg.Complete() {
-			return
-		}
-
-		// open file
-		f, err := os.Open(filename)
-		if err != nil {
-			return nil, err
-		}
-		defer func() {
-			if err != nil {
-				// add file name to error
-				err = fmt.Errorf("%s: %v", filename, err)
-			}
-		}()
-		rc = f
-	}
-	defer rc.Close()
-
-	var hdr string
-	buf := bufio.NewReader(rc)
-	if hdr, _, err = FindExportData(buf); err != nil {
-		return
-	}
-
-	switch hdr {
-	case "$$\n":
-		// Work-around if we don't have a filename; happens only if lookup != nil.
-		// Either way, the filename is only needed for importer error messages, so
-		// this is fine.
-		if filename == "" {
-			filename = path
-		}
-		return ImportData(packages, filename, id, buf)
-
-	case "$$B\n":
-		var data []byte
-		data, err = ioutil.ReadAll(buf)
-		if err != nil {
-			break
-		}
-
-		// TODO(gri): allow clients of go/importer to provide a FileSet.
-		// Or, define a new standard go/types/gcexportdata package.
-		fset := token.NewFileSet()
-
-		// The indexed export format starts with an 'i'; the older
-		// binary export format starts with a 'c', 'd', or 'v'
-		// (from "version"). Select appropriate importer.
-		if len(data) > 0 && data[0] == 'i' {
-			_, pkg, err = IImportData(fset, packages, data[1:], id)
-		} else {
-			_, pkg, err = BImportData(fset, packages, data, id)
-		}
-
-	default:
-		err = fmt.Errorf("unknown export data header: %q", hdr)
-	}
-
-	return
-}
-
-// ----------------------------------------------------------------------------
-// Parser
-
-// TODO(gri) Imported objects don't have position information.
-//           Ideally use the debug table line info; alternatively
-//           create some fake position (or the position of the
-//           import). That way error messages referring to imported
-//           objects can print meaningful information.
-
-// parser parses the exports inside a gc compiler-produced
-// object/archive file and populates its scope with the results.
-type parser struct {
-	scanner    scanner.Scanner
-	tok        rune                      // current token
-	lit        string                    // literal string; only valid for Ident, Int, String tokens
-	id         string                    // package id of imported package
-	sharedPkgs map[string]*types.Package // package id -> package object (across importer)
-	localPkgs  map[string]*types.Package // package id -> package object (just this package)
-}
-
-func (p *parser) init(filename, id string, src io.Reader, packages map[string]*types.Package) {
-	p.scanner.Init(src)
-	p.scanner.Error = func(_ *scanner.Scanner, msg string) { p.error(msg) }
-	p.scanner.Mode = scanner.ScanIdents | scanner.ScanInts | scanner.ScanChars | scanner.ScanStrings | scanner.ScanComments | scanner.SkipComments
-	p.scanner.Whitespace = 1<<'\t' | 1<<' '
-	p.scanner.Filename = filename // for good error messages
-	p.next()
-	p.id = id
-	p.sharedPkgs = packages
-	if debug {
-		// check consistency of packages map
-		for _, pkg := range packages {
-			if pkg.Name() == "" {
-				fmt.Printf("no package name for %s\n", pkg.Path())
-			}
-		}
-	}
-}
-
-func (p *parser) next() {
-	p.tok = p.scanner.Scan()
-	switch p.tok {
-	case scanner.Ident, scanner.Int, scanner.Char, scanner.String, '·':
-		p.lit = p.scanner.TokenText()
-	default:
-		p.lit = ""
-	}
-	if debug {
-		fmt.Printf("%s: %q -> %q\n", scanner.TokenString(p.tok), p.scanner.TokenText(), p.lit)
-	}
-}
-
-func declTypeName(pkg *types.Package, name string) *types.TypeName {
-	scope := pkg.Scope()
-	if obj := scope.Lookup(name); obj != nil {
-		return obj.(*types.TypeName)
-	}
-	obj := types.NewTypeName(token.NoPos, pkg, name, nil)
-	// a named type may be referred to before the underlying type
-	// is known - set it up
-	types.NewNamed(obj, nil, nil)
-	scope.Insert(obj)
-	return obj
-}
-
-// ----------------------------------------------------------------------------
-// Error handling
-
-// Internal errors are boxed as importErrors.
-type importError struct {
-	pos scanner.Position
-	err error
-}
-
-func (e importError) Error() string {
-	return fmt.Sprintf("import error %s (byte offset = %d): %s", e.pos, e.pos.Offset, e.err)
-}
-
-func (p *parser) error(err interface{}) {
-	if s, ok := err.(string); ok {
-		err = errors.New(s)
-	}
-	// panic with a runtime.Error if err is not an error
-	panic(importError{p.scanner.Pos(), err.(error)})
-}
-
-func (p *parser) errorf(format string, args ...interface{}) {
-	p.error(fmt.Sprintf(format, args...))
-}
-
-func (p *parser) expect(tok rune) string {
-	lit := p.lit
-	if p.tok != tok {
-		p.errorf("expected %s, got %s (%s)", scanner.TokenString(tok), scanner.TokenString(p.tok), lit)
-	}
-	p.next()
-	return lit
-}
-
-func (p *parser) expectSpecial(tok string) {
-	sep := 'x' // not white space
-	i := 0
-	for i < len(tok) && p.tok == rune(tok[i]) && sep > ' ' {
-		sep = p.scanner.Peek() // if sep <= ' ', there is white space before the next token
-		p.next()
-		i++
-	}
-	if i < len(tok) {
-		p.errorf("expected %q, got %q", tok, tok[0:i])
-	}
-}
-
-func (p *parser) expectKeyword(keyword string) {
-	lit := p.expect(scanner.Ident)
-	if lit != keyword {
-		p.errorf("expected keyword %s, got %q", keyword, lit)
-	}
-}
-
-// ----------------------------------------------------------------------------
-// Qualified and unqualified names
-
-// PackageId = string_lit .
-//
-func (p *parser) parsePackageID() string {
-	id, err := strconv.Unquote(p.expect(scanner.String))
-	if err != nil {
-		p.error(err)
-	}
-	// id == "" stands for the imported package id
-	// (only known at time of package installation)
-	if id == "" {
-		id = p.id
-	}
-	return id
-}
-
-// PackageName = ident .
-//
-func (p *parser) parsePackageName() string {
-	return p.expect(scanner.Ident)
-}
-
-// dotIdentifier = ( ident | '·' ) { ident | int | '·' } .
-func (p *parser) parseDotIdent() string {
-	ident := ""
-	if p.tok != scanner.Int {
-		sep := 'x' // not white space
-		for (p.tok == scanner.Ident || p.tok == scanner.Int || p.tok == '·') && sep > ' ' {
-			ident += p.lit
-			sep = p.scanner.Peek() // if sep <= ' ', there is white space before the next token
-			p.next()
-		}
-	}
-	if ident == "" {
-		p.expect(scanner.Ident) // use expect() for error handling
-	}
-	return ident
-}
-
-// QualifiedName = "@" PackageId "." ( "?" | dotIdentifier ) .
-//
-func (p *parser) parseQualifiedName() (id, name string) {
-	p.expect('@')
-	id = p.parsePackageID()
-	p.expect('.')
-	// Per rev f280b8a485fd (10/2/2013), qualified names may be used for anonymous fields.
-	if p.tok == '?' {
-		p.next()
-	} else {
-		name = p.parseDotIdent()
-	}
-	return
-}
-
-// getPkg returns the package for a given id. If the package is
-// not found, create the package and add it to the p.localPkgs
-// and p.sharedPkgs maps. name is the (expected) name of the
-// package. If name == "", the package name is expected to be
-// set later via an import clause in the export data.
-//
-// id identifies a package, usually by a canonical package path like
-// "encoding/json" but possibly by a non-canonical import path like
-// "./json".
-//
-func (p *parser) getPkg(id, name string) *types.Package {
-	// package unsafe is not in the packages maps - handle explicitly
-	if id == "unsafe" {
-		return types.Unsafe
-	}
-
-	pkg := p.localPkgs[id]
-	if pkg == nil {
-		// first import of id from this package
-		pkg = p.sharedPkgs[id]
-		if pkg == nil {
-			// first import of id by this importer;
-			// add (possibly unnamed) pkg to shared packages
-			pkg = types.NewPackage(id, name)
-			p.sharedPkgs[id] = pkg
-		}
-		// add (possibly unnamed) pkg to local packages
-		if p.localPkgs == nil {
-			p.localPkgs = make(map[string]*types.Package)
-		}
-		p.localPkgs[id] = pkg
-	} else if name != "" {
-		// package exists already and we have an expected package name;
-		// make sure names match or set package name if necessary
-		if pname := pkg.Name(); pname == "" {
-			pkg.SetName(name)
-		} else if pname != name {
-			p.errorf("%s package name mismatch: %s (given) vs %s (expected)", id, pname, name)
-		}
-	}
-	return pkg
-}
-
-// parseExportedName is like parseQualifiedName, but
-// the package id is resolved to an imported *types.Package.
-//
-func (p *parser) parseExportedName() (pkg *types.Package, name string) {
-	id, name := p.parseQualifiedName()
-	pkg = p.getPkg(id, "")
-	return
-}
-
-// ----------------------------------------------------------------------------
-// Types
-
-// BasicType = identifier .
-//
-func (p *parser) parseBasicType() types.Type {
-	id := p.expect(scanner.Ident)
-	obj := types.Universe.Lookup(id)
-	if obj, ok := obj.(*types.TypeName); ok {
-		return obj.Type()
-	}
-	p.errorf("not a basic type: %s", id)
-	return nil
-}
-
-// ArrayType = "[" int_lit "]" Type .
-//
-func (p *parser) parseArrayType(parent *types.Package) types.Type {
-	// "[" already consumed and lookahead known not to be "]"
-	lit := p.expect(scanner.Int)
-	p.expect(']')
-	elem := p.parseType(parent)
-	n, err := strconv.ParseInt(lit, 10, 64)
-	if err != nil {
-		p.error(err)
-	}
-	return types.NewArray(elem, n)
-}
-
-// MapType = "map" "[" Type "]" Type .
-//
-func (p *parser) parseMapType(parent *types.Package) types.Type {
-	p.expectKeyword("map")
-	p.expect('[')
-	key := p.parseType(parent)
-	p.expect(']')
-	elem := p.parseType(parent)
-	return types.NewMap(key, elem)
-}
-
-// Name = identifier | "?" | QualifiedName .
-//
-// For unqualified and anonymous names, the returned package is the parent
-// package unless parent == nil, in which case the returned package is the
-// package being imported. (The parent package is not nil if the name
-// is an unqualified struct field or interface method name belonging to a
-// type declared in another package.)
-//
-// For qualified names, the returned package is nil (and not created if
-// it doesn't exist yet) unless materializePkg is set (which creates an
-// unnamed package with valid package path). In the latter case, a
-// subsequent import clause is expected to provide a name for the package.
-//
-func (p *parser) parseName(parent *types.Package, materializePkg bool) (pkg *types.Package, name string) {
-	pkg = parent
-	if pkg == nil {
-		pkg = p.sharedPkgs[p.id]
-	}
-	switch p.tok {
-	case scanner.Ident:
-		name = p.lit
-		p.next()
-	case '?':
-		// anonymous
-		p.next()
-	case '@':
-		// exported name prefixed with package path
-		pkg = nil
-		var id string
-		id, name = p.parseQualifiedName()
-		if materializePkg {
-			pkg = p.getPkg(id, "")
-		}
-	default:
-		p.error("name expected")
-	}
-	return
-}
-
-func deref(typ types.Type) types.Type {
-	if p, _ := typ.(*types.Pointer); p != nil {
-		return p.Elem()
-	}
-	return typ
-}
-
-// Field = Name Type [ string_lit ] .
-//
-func (p *parser) parseField(parent *types.Package) (*types.Var, string) {
-	pkg, name := p.parseName(parent, true)
-
-	if name == "_" {
-		// Blank fields should be package-qualified because they
-		// are unexported identifiers, but gc does not qualify them.
-		// Assuming that the ident belongs to the current package
-		// causes types to change during re-exporting, leading
-		// to spurious "can't assign A to B" errors from go/types.
-		// As a workaround, pretend all blank fields belong
-		// to the same unique dummy package.
-		const blankpkg = "<_>"
-		pkg = p.getPkg(blankpkg, blankpkg)
-	}
-
-	typ := p.parseType(parent)
-	anonymous := false
-	if name == "" {
-		// anonymous field - typ must be T or *T and T must be a type name
-		switch typ := deref(typ).(type) {
-		case *types.Basic: // basic types are named types
-			pkg = nil // objects defined in Universe scope have no package
-			name = typ.Name()
-		case *types.Named:
-			name = typ.Obj().Name()
-		default:
-			p.errorf("anonymous field expected")
-		}
-		anonymous = true
-	}
-	tag := ""
-	if p.tok == scanner.String {
-		s := p.expect(scanner.String)
-		var err error
-		tag, err = strconv.Unquote(s)
-		if err != nil {
-			p.errorf("invalid struct tag %s: %s", s, err)
-		}
-	}
-	return types.NewField(token.NoPos, pkg, name, typ, anonymous), tag
-}
-
-// StructType = "struct" "{" [ FieldList ] "}" .
-// FieldList  = Field { ";" Field } .
-//
-func (p *parser) parseStructType(parent *types.Package) types.Type {
-	var fields []*types.Var
-	var tags []string
-
-	p.expectKeyword("struct")
-	p.expect('{')
-	for i := 0; p.tok != '}' && p.tok != scanner.EOF; i++ {
-		if i > 0 {
-			p.expect(';')
-		}
-		fld, tag := p.parseField(parent)
-		if tag != "" && tags == nil {
-			tags = make([]string, i)
-		}
-		if tags != nil {
-			tags = append(tags, tag)
-		}
-		fields = append(fields, fld)
-	}
-	p.expect('}')
-
-	return types.NewStruct(fields, tags)
-}
-
-// Parameter = ( identifier | "?" ) [ "..." ] Type [ string_lit ] .
-//
-func (p *parser) parseParameter() (par *types.Var, isVariadic bool) {
-	_, name := p.parseName(nil, false)
-	// remove gc-specific parameter numbering
-	if i := strings.Index(name, "·"); i >= 0 {
-		name = name[:i]
-	}
-	if p.tok == '.' {
-		p.expectSpecial("...")
-		isVariadic = true
-	}
-	typ := p.parseType(nil)
-	if isVariadic {
-		typ = types.NewSlice(typ)
-	}
-	// ignore argument tag (e.g. "noescape")
-	if p.tok == scanner.String {
-		p.next()
-	}
-	// TODO(gri) should we provide a package?
-	par = types.NewVar(token.NoPos, nil, name, typ)
-	return
-}
-
-// Parameters    = "(" [ ParameterList ] ")" .
-// ParameterList = { Parameter "," } Parameter .
-//
-func (p *parser) parseParameters() (list []*types.Var, isVariadic bool) {
-	p.expect('(')
-	for p.tok != ')' && p.tok != scanner.EOF {
-		if len(list) > 0 {
-			p.expect(',')
-		}
-		par, variadic := p.parseParameter()
-		list = append(list, par)
-		if variadic {
-			if isVariadic {
-				p.error("... not on final argument")
-			}
-			isVariadic = true
-		}
-	}
-	p.expect(')')
-
-	return
-}
-
-// Signature = Parameters [ Result ] .
-// Result    = Type | Parameters .
-//
-func (p *parser) parseSignature(recv *types.Var) *types.Signature {
-	params, isVariadic := p.parseParameters()
-
-	// optional result type
-	var results []*types.Var
-	if p.tok == '(' {
-		var variadic bool
-		results, variadic = p.parseParameters()
-		if variadic {
-			p.error("... not permitted on result type")
-		}
-	}
-
-	return types.NewSignature(recv, types.NewTuple(params...), types.NewTuple(results...), isVariadic)
-}
-
-// InterfaceType = "interface" "{" [ MethodList ] "}" .
-// MethodList    = Method { ";" Method } .
-// Method        = Name Signature .
-//
-// The methods of embedded interfaces are always "inlined"
-// by the compiler and thus embedded interfaces are never
-// visible in the export data.
-//
-func (p *parser) parseInterfaceType(parent *types.Package) types.Type {
-	var methods []*types.Func
-
-	p.expectKeyword("interface")
-	p.expect('{')
-	for i := 0; p.tok != '}' && p.tok != scanner.EOF; i++ {
-		if i > 0 {
-			p.expect(';')
-		}
-		pkg, name := p.parseName(parent, true)
-		sig := p.parseSignature(nil)
-		methods = append(methods, types.NewFunc(token.NoPos, pkg, name, sig))
-	}
-	p.expect('}')
-
-	// Complete requires the type's embedded interfaces to be fully defined,
-	// but we do not define any
-	return newInterface(methods, nil).Complete()
-}
-
-// ChanType = ( "chan" [ "<-" ] | "<-" "chan" ) Type .
-//
-func (p *parser) parseChanType(parent *types.Package) types.Type {
-	dir := types.SendRecv
-	if p.tok == scanner.Ident {
-		p.expectKeyword("chan")
-		if p.tok == '<' {
-			p.expectSpecial("<-")
-			dir = types.SendOnly
-		}
-	} else {
-		p.expectSpecial("<-")
-		p.expectKeyword("chan")
-		dir = types.RecvOnly
-	}
-	elem := p.parseType(parent)
-	return types.NewChan(dir, elem)
-}
-
-// Type =
-//	BasicType | TypeName | ArrayType | SliceType | StructType |
-//      PointerType | FuncType | InterfaceType | MapType | ChanType |
-//      "(" Type ")" .
-//
-// BasicType   = ident .
-// TypeName    = ExportedName .
-// SliceType   = "[" "]" Type .
-// PointerType = "*" Type .
-// FuncType    = "func" Signature .
-//
-func (p *parser) parseType(parent *types.Package) types.Type {
-	switch p.tok {
-	case scanner.Ident:
-		switch p.lit {
-		default:
-			return p.parseBasicType()
-		case "struct":
-			return p.parseStructType(parent)
-		case "func":
-			// FuncType
-			p.next()
-			return p.parseSignature(nil)
-		case "interface":
-			return p.parseInterfaceType(parent)
-		case "map":
-			return p.parseMapType(parent)
-		case "chan":
-			return p.parseChanType(parent)
-		}
-	case '@':
-		// TypeName
-		pkg, name := p.parseExportedName()
-		return declTypeName(pkg, name).Type()
-	case '[':
-		p.next() // look ahead
-		if p.tok == ']' {
-			// SliceType
-			p.next()
-			return types.NewSlice(p.parseType(parent))
-		}
-		return p.parseArrayType(parent)
-	case '*':
-		// PointerType
-		p.next()
-		return types.NewPointer(p.parseType(parent))
-	case '<':
-		return p.parseChanType(parent)
-	case '(':
-		// "(" Type ")"
-		p.next()
-		typ := p.parseType(parent)
-		p.expect(')')
-		return typ
-	}
-	p.errorf("expected type, got %s (%q)", scanner.TokenString(p.tok), p.lit)
-	return nil
-}
-
-// ----------------------------------------------------------------------------
-// Declarations
-
-// ImportDecl = "import" PackageName PackageId .
-//
-func (p *parser) parseImportDecl() {
-	p.expectKeyword("import")
-	name := p.parsePackageName()
-	p.getPkg(p.parsePackageID(), name)
-}
-
-// int_lit = [ "+" | "-" ] { "0" ... "9" } .
-//
-func (p *parser) parseInt() string {
-	s := ""
-	switch p.tok {
-	case '-':
-		s = "-"
-		p.next()
-	case '+':
-		p.next()
-	}
-	return s + p.expect(scanner.Int)
-}
-
-// number = int_lit [ "p" int_lit ] .
-//
-func (p *parser) parseNumber() (typ *types.Basic, val constant.Value) {
-	// mantissa
-	mant := constant.MakeFromLiteral(p.parseInt(), token.INT, 0)
-	if mant == nil {
-		panic("invalid mantissa")
-	}
-
-	if p.lit == "p" {
-		// exponent (base 2)
-		p.next()
-		exp, err := strconv.ParseInt(p.parseInt(), 10, 0)
-		if err != nil {
-			p.error(err)
-		}
-		if exp < 0 {
-			denom := constant.MakeInt64(1)
-			denom = constant.Shift(denom, token.SHL, uint(-exp))
-			typ = types.Typ[types.UntypedFloat]
-			val = constant.BinaryOp(mant, token.QUO, denom)
-			return
-		}
-		if exp > 0 {
-			mant = constant.Shift(mant, token.SHL, uint(exp))
-		}
-		typ = types.Typ[types.UntypedFloat]
-		val = mant
-		return
-	}
-
-	typ = types.Typ[types.UntypedInt]
-	val = mant
-	return
-}
-
-// ConstDecl   = "const" ExportedName [ Type ] "=" Literal .
-// Literal     = bool_lit | int_lit | float_lit | complex_lit | rune_lit | string_lit .
-// bool_lit    = "true" | "false" .
-// complex_lit = "(" float_lit "+" float_lit "i" ")" .
-// rune_lit    = "(" int_lit "+" int_lit ")" .
-// string_lit  = `"` { unicode_char } `"` .
-//
-func (p *parser) parseConstDecl() {
-	p.expectKeyword("const")
-	pkg, name := p.parseExportedName()
-
-	var typ0 types.Type
-	if p.tok != '=' {
-		// constant types are never structured - no need for parent type
-		typ0 = p.parseType(nil)
-	}
-
-	p.expect('=')
-	var typ types.Type
-	var val constant.Value
-	switch p.tok {
-	case scanner.Ident:
-		// bool_lit
-		if p.lit != "true" && p.lit != "false" {
-			p.error("expected true or false")
-		}
-		typ = types.Typ[types.UntypedBool]
-		val = constant.MakeBool(p.lit == "true")
-		p.next()
-
-	case '-', scanner.Int:
-		// int_lit
-		typ, val = p.parseNumber()
-
-	case '(':
-		// complex_lit or rune_lit
-		p.next()
-		if p.tok == scanner.Char {
-			p.next()
-			p.expect('+')
-			typ = types.Typ[types.UntypedRune]
-			_, val = p.parseNumber()
-			p.expect(')')
-			break
-		}
-		_, re := p.parseNumber()
-		p.expect('+')
-		_, im := p.parseNumber()
-		p.expectKeyword("i")
-		p.expect(')')
-		typ = types.Typ[types.UntypedComplex]
-		val = constant.BinaryOp(re, token.ADD, constant.MakeImag(im))
-
-	case scanner.Char:
-		// rune_lit
-		typ = types.Typ[types.UntypedRune]
-		val = constant.MakeFromLiteral(p.lit, token.CHAR, 0)
-		p.next()
-
-	case scanner.String:
-		// string_lit
-		typ = types.Typ[types.UntypedString]
-		val = constant.MakeFromLiteral(p.lit, token.STRING, 0)
-		p.next()
-
-	default:
-		p.errorf("expected literal got %s", scanner.TokenString(p.tok))
-	}
-
-	if typ0 == nil {
-		typ0 = typ
-	}
-
-	pkg.Scope().Insert(types.NewConst(token.NoPos, pkg, name, typ0, val))
-}
-
-// TypeDecl = "type" ExportedName Type .
-//
-func (p *parser) parseTypeDecl() {
-	p.expectKeyword("type")
-	pkg, name := p.parseExportedName()
-	obj := declTypeName(pkg, name)
-
-	// The type object may have been imported before and thus already
-	// have a type associated with it. We still need to parse the type
-	// structure, but throw it away if the object already has a type.
-	// This ensures that all imports refer to the same type object for
-	// a given type declaration.
-	typ := p.parseType(pkg)
-
-	if name := obj.Type().(*types.Named); name.Underlying() == nil {
-		name.SetUnderlying(typ)
-	}
-}
-
-// VarDecl = "var" ExportedName Type .
-//
-func (p *parser) parseVarDecl() {
-	p.expectKeyword("var")
-	pkg, name := p.parseExportedName()
-	typ := p.parseType(pkg)
-	pkg.Scope().Insert(types.NewVar(token.NoPos, pkg, name, typ))
-}
-
-// Func = Signature [ Body ] .
-// Body = "{" ... "}" .
-//
-func (p *parser) parseFunc(recv *types.Var) *types.Signature {
-	sig := p.parseSignature(recv)
-	if p.tok == '{' {
-		p.next()
-		for i := 1; i > 0; p.next() {
-			switch p.tok {
-			case '{':
-				i++
-			case '}':
-				i--
-			}
-		}
-	}
-	return sig
-}
-
-// MethodDecl = "func" Receiver Name Func .
-// Receiver   = "(" ( identifier | "?" ) [ "*" ] ExportedName ")" .
-//
-func (p *parser) parseMethodDecl() {
-	// "func" already consumed
-	p.expect('(')
-	recv, _ := p.parseParameter() // receiver
-	p.expect(')')
-
-	// determine receiver base type object
-	base := deref(recv.Type()).(*types.Named)
-
-	// parse method name, signature, and possibly inlined body
-	_, name := p.parseName(nil, false)
-	sig := p.parseFunc(recv)
-
-	// methods always belong to the same package as the base type object
-	pkg := base.Obj().Pkg()
-
-	// add method to type unless type was imported before
-	// and method exists already
-	// TODO(gri) This leads to a quadratic algorithm - ok for now because method counts are small.
-	base.AddMethod(types.NewFunc(token.NoPos, pkg, name, sig))
-}
-
-// FuncDecl = "func" ExportedName Func .
-//
-func (p *parser) parseFuncDecl() {
-	// "func" already consumed
-	pkg, name := p.parseExportedName()
-	typ := p.parseFunc(nil)
-	pkg.Scope().Insert(types.NewFunc(token.NoPos, pkg, name, typ))
-}
-
-// Decl = [ ImportDecl | ConstDecl | TypeDecl | VarDecl | FuncDecl | MethodDecl ] "\n" .
-//
-func (p *parser) parseDecl() {
-	if p.tok == scanner.Ident {
-		switch p.lit {
-		case "import":
-			p.parseImportDecl()
-		case "const":
-			p.parseConstDecl()
-		case "type":
-			p.parseTypeDecl()
-		case "var":
-			p.parseVarDecl()
-		case "func":
-			p.next() // look ahead
-			if p.tok == '(' {
-				p.parseMethodDecl()
-			} else {
-				p.parseFuncDecl()
-			}
-		}
-	}
-	p.expect('\n')
-}
-
-// ----------------------------------------------------------------------------
-// Export
-
-// Export        = "PackageClause { Decl } "$$" .
-// PackageClause = "package" PackageName [ "safe" ] "\n" .
-//
-func (p *parser) parseExport() *types.Package {
-	p.expectKeyword("package")
-	name := p.parsePackageName()
-	if p.tok == scanner.Ident && p.lit == "safe" {
-		// package was compiled with -u option - ignore
-		p.next()
-	}
-	p.expect('\n')
-
-	pkg := p.getPkg(p.id, name)
-
-	for p.tok != '$' && p.tok != scanner.EOF {
-		p.parseDecl()
-	}
-
-	if ch := p.scanner.Peek(); p.tok != '$' || ch != '$' {
-		// don't call next()/expect() since reading past the
-		// export data may cause scanner errors (e.g. NUL chars)
-		p.errorf("expected '$$', got %s %c", scanner.TokenString(p.tok), ch)
-	}
-
-	if n := p.scanner.ErrorCount; n != 0 {
-		p.errorf("expected no scanner errors, got %d", n)
-	}
-
-	// Record all locally referenced packages as imports.
-	var imports []*types.Package
-	for id, pkg2 := range p.localPkgs {
-		if pkg2.Name() == "" {
-			p.errorf("%s package has no name", id)
-		}
-		if id == p.id {
-			continue // avoid self-edge
-		}
-		imports = append(imports, pkg2)
-	}
-	sort.Sort(byPath(imports))
-	pkg.SetImports(imports)
-
-	// package was imported completely and without errors
-	pkg.MarkComplete()
-
-	return pkg
-}
-
-type byPath []*types.Package
-
-func (a byPath) Len() int           { return len(a) }
-func (a byPath) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
-func (a byPath) Less(i, j int) bool { return a[i].Path() < a[j].Path() }
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go
deleted file mode 100644
index b4d51f3..0000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go
+++ /dev/null
@@ -1,971 +0,0 @@
-// Copyright 2019 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Indexed binary package export.
-// This file was derived from $GOROOT/src/cmd/compile/internal/gc/iexport.go;
-// see that file for specification of the format.
-
-package gcimporter
-
-import (
-	"bytes"
-	"encoding/binary"
-	"fmt"
-	"go/ast"
-	"go/constant"
-	"go/token"
-	"go/types"
-	"io"
-	"math/big"
-	"reflect"
-	"sort"
-	"strings"
-
-	"golang.org/x/tools/internal/typeparams"
-)
-
-// Current bundled export format version. Increase with each format change.
-// 0: initial implementation
-const bundleVersion = 0
-
-// IExportData writes indexed export data for pkg to out.
-//
-// If no file set is provided, position info will be missing.
-// The package path of the top-level package will not be recorded,
-// so that calls to IImportData can override with a provided package path.
-func IExportData(out io.Writer, fset *token.FileSet, pkg *types.Package) error {
-	return iexportCommon(out, fset, false, iexportVersion, []*types.Package{pkg})
-}
-
-// IExportBundle writes an indexed export bundle for pkgs to out.
-func IExportBundle(out io.Writer, fset *token.FileSet, pkgs []*types.Package) error {
-	return iexportCommon(out, fset, true, iexportVersion, pkgs)
-}
-
-func iexportCommon(out io.Writer, fset *token.FileSet, bundle bool, version int, pkgs []*types.Package) (err error) {
-	if !debug {
-		defer func() {
-			if e := recover(); e != nil {
-				if ierr, ok := e.(internalError); ok {
-					err = ierr
-					return
-				}
-				// Not an internal error; panic again.
-				panic(e)
-			}
-		}()
-	}
-
-	p := iexporter{
-		fset:        fset,
-		version:     version,
-		allPkgs:     map[*types.Package]bool{},
-		stringIndex: map[string]uint64{},
-		declIndex:   map[types.Object]uint64{},
-		tparamNames: map[types.Object]string{},
-		typIndex:    map[types.Type]uint64{},
-	}
-	if !bundle {
-		p.localpkg = pkgs[0]
-	}
-
-	for i, pt := range predeclared() {
-		p.typIndex[pt] = uint64(i)
-	}
-	if len(p.typIndex) > predeclReserved {
-		panic(internalErrorf("too many predeclared types: %d > %d", len(p.typIndex), predeclReserved))
-	}
-
-	// Initialize work queue with exported declarations.
-	for _, pkg := range pkgs {
-		scope := pkg.Scope()
-		for _, name := range scope.Names() {
-			if ast.IsExported(name) {
-				p.pushDecl(scope.Lookup(name))
-			}
-		}
-
-		if bundle {
-			// Ensure pkg and its imports are included in the index.
-			p.allPkgs[pkg] = true
-			for _, imp := range pkg.Imports() {
-				p.allPkgs[imp] = true
-			}
-		}
-	}
-
-	// Loop until no more work.
-	for !p.declTodo.empty() {
-		p.doDecl(p.declTodo.popHead())
-	}
-
-	// Append indices to data0 section.
-	dataLen := uint64(p.data0.Len())
-	w := p.newWriter()
-	w.writeIndex(p.declIndex)
-
-	if bundle {
-		w.uint64(uint64(len(pkgs)))
-		for _, pkg := range pkgs {
-			w.pkg(pkg)
-			imps := pkg.Imports()
-			w.uint64(uint64(len(imps)))
-			for _, imp := range imps {
-				w.pkg(imp)
-			}
-		}
-	}
-	w.flush()
-
-	// Assemble header.
-	var hdr intWriter
-	if bundle {
-		hdr.uint64(bundleVersion)
-	}
-	hdr.uint64(uint64(p.version))
-	hdr.uint64(uint64(p.strings.Len()))
-	hdr.uint64(dataLen)
-
-	// Flush output.
-	io.Copy(out, &hdr)
-	io.Copy(out, &p.strings)
-	io.Copy(out, &p.data0)
-
-	return nil
-}
-
-// writeIndex writes out an object index. mainIndex indicates whether
-// we're writing out the main index, which is also read by
-// non-compiler tools and includes a complete package description
-// (i.e., name and height).
-func (w *exportWriter) writeIndex(index map[types.Object]uint64) {
-	type pkgObj struct {
-		obj  types.Object
-		name string // qualified name; differs from obj.Name for type params
-	}
-	// Build a map from packages to objects from that package.
-	pkgObjs := map[*types.Package][]pkgObj{}
-
-	// For the main index, make sure to include every package that
-	// we reference, even if we're not exporting (or reexporting)
-	// any symbols from it.
-	if w.p.localpkg != nil {
-		pkgObjs[w.p.localpkg] = nil
-	}
-	for pkg := range w.p.allPkgs {
-		pkgObjs[pkg] = nil
-	}
-
-	for obj := range index {
-		name := w.p.indexName(obj)
-		pkgObjs[obj.Pkg()] = append(pkgObjs[obj.Pkg()], pkgObj{obj, name})
-	}
-
-	var pkgs []*types.Package
-	for pkg, objs := range pkgObjs {
-		pkgs = append(pkgs, pkg)
-
-		sort.Slice(objs, func(i, j int) bool {
-			return objs[i].name < objs[j].name
-		})
-	}
-
-	sort.Slice(pkgs, func(i, j int) bool {
-		return w.exportPath(pkgs[i]) < w.exportPath(pkgs[j])
-	})
-
-	w.uint64(uint64(len(pkgs)))
-	for _, pkg := range pkgs {
-		w.string(w.exportPath(pkg))
-		w.string(pkg.Name())
-		w.uint64(uint64(0)) // package height is not needed for go/types
-
-		objs := pkgObjs[pkg]
-		w.uint64(uint64(len(objs)))
-		for _, obj := range objs {
-			w.string(obj.name)
-			w.uint64(index[obj.obj])
-		}
-	}
-}
-
-// indexName returns the 'indexed' name of an object. It differs from
-// obj.Name() only for type parameter names, where the name is qualified by
-// owner.
-func (p *iexporter) indexName(obj types.Object) (res string) {
-	if name := p.tparamNames[obj]; name != "" {
-		return name
-	}
-	return obj.Name()
-}
-
-type iexporter struct {
-	fset    *token.FileSet
-	out     *bytes.Buffer
-	version int
-
-	localpkg *types.Package
-
-	// allPkgs tracks all packages that have been referenced by
-	// the export data, so we can ensure to include them in the
-	// main index.
-	allPkgs map[*types.Package]bool
-
-	declTodo objQueue
-
-	strings     intWriter
-	stringIndex map[string]uint64
-
-	data0       intWriter
-	declIndex   map[types.Object]uint64
-	tparamNames map[types.Object]string // typeparam->qualified name
-	typIndex    map[types.Type]uint64
-
-	indent int // for tracing support
-}
-
-func (p *iexporter) trace(format string, args ...interface{}) {
-	if !trace {
-		// Call sites should also be guarded, but having this check here allows
-		// easily enabling/disabling debug trace statements.
-		return
-	}
-	fmt.Printf(strings.Repeat("..", p.indent)+format+"\n", args...)
-}
-
-// stringOff returns the offset of s within the string section.
-// If not already present, it's added to the end.
-func (p *iexporter) stringOff(s string) uint64 {
-	off, ok := p.stringIndex[s]
-	if !ok {
-		off = uint64(p.strings.Len())
-		p.stringIndex[s] = off
-
-		p.strings.uint64(uint64(len(s)))
-		p.strings.WriteString(s)
-	}
-	return off
-}
-
-// pushDecl adds n to the declaration work queue, if not already present.
-func (p *iexporter) pushDecl(obj types.Object) {
-	// Package unsafe is known to the compiler and predeclared.
-	assert(obj.Pkg() != types.Unsafe)
-
-	if _, ok := p.declIndex[obj]; ok {
-		return
-	}
-
-	p.declIndex[obj] = ^uint64(0) // mark obj present in work queue
-	p.declTodo.pushTail(obj)
-}
-
-// exportWriter handles writing out individual data section chunks.
-type exportWriter struct {
-	p *iexporter
-
-	data       intWriter
-	currPkg    *types.Package
-	prevFile   string
-	prevLine   int64
-	prevColumn int64
-}
-
-func (w *exportWriter) exportPath(pkg *types.Package) string {
-	if pkg == w.p.localpkg {
-		return ""
-	}
-	return pkg.Path()
-}
-
-func (p *iexporter) doDecl(obj types.Object) {
-	if trace {
-		p.trace("exporting decl %v (%T)", obj, obj)
-		p.indent++
-		defer func() {
-			p.indent--
-			p.trace("=> %s", obj)
-		}()
-	}
-	w := p.newWriter()
-	w.setPkg(obj.Pkg(), false)
-
-	switch obj := obj.(type) {
-	case *types.Var:
-		w.tag('V')
-		w.pos(obj.Pos())
-		w.typ(obj.Type(), obj.Pkg())
-
-	case *types.Func:
-		sig, _ := obj.Type().(*types.Signature)
-		if sig.Recv() != nil {
-			panic(internalErrorf("unexpected method: %v", sig))
-		}
-
-		// Function.
-		if typeparams.ForSignature(sig).Len() == 0 {
-			w.tag('F')
-		} else {
-			w.tag('G')
-		}
-		w.pos(obj.Pos())
-		// The tparam list of the function type is the
-		// declaration of the type params. So, write out the type
-		// params right now. Then those type params will be
-		// referenced via their type offset (via typOff) in all
-		// other places in the signature and function that they
-		// are used.
-		if tparams := typeparams.ForSignature(sig); tparams.Len() > 0 {
-			w.tparamList(obj, tparams, obj.Pkg())
-		}
-		w.signature(sig)
-
-	case *types.Const:
-		w.tag('C')
-		w.pos(obj.Pos())
-		w.value(obj.Type(), obj.Val())
-
-	case *types.TypeName:
-		t := obj.Type()
-
-		if tparam, ok := t.(*typeparams.TypeParam); ok {
-			w.tag('P')
-			w.pos(obj.Pos())
-			constraint := tparam.Constraint()
-			if p.version >= iexportVersionGo1_18 {
-				implicit := false
-				if iface, _ := constraint.(*types.Interface); iface != nil {
-					implicit = typeparams.IsImplicit(iface)
-				}
-				w.bool(implicit)
-			}
-			w.typ(constraint, obj.Pkg())
-			break
-		}
-
-		if obj.IsAlias() {
-			w.tag('A')
-			w.pos(obj.Pos())
-			w.typ(t, obj.Pkg())
-			break
-		}
-
-		// Defined type.
-		named, ok := t.(*types.Named)
-		if !ok {
-			panic(internalErrorf("%s is not a defined type", t))
-		}
-
-		if typeparams.ForNamed(named).Len() == 0 {
-			w.tag('T')
-		} else {
-			w.tag('U')
-		}
-		w.pos(obj.Pos())
-
-		if typeparams.ForNamed(named).Len() > 0 {
-			w.tparamList(obj, typeparams.ForNamed(named), obj.Pkg())
-		}
-
-		underlying := obj.Type().Underlying()
-		w.typ(underlying, obj.Pkg())
-
-		if types.IsInterface(t) {
-			break
-		}
-
-		n := named.NumMethods()
-		w.uint64(uint64(n))
-		for i := 0; i < n; i++ {
-			m := named.Method(i)
-			w.pos(m.Pos())
-			w.string(m.Name())
-			sig, _ := m.Type().(*types.Signature)
-
-			// Receiver type parameters are type arguments of the receiver type, so
-			// their name must be qualified before exporting recv.
-			rparams := typeparams.RecvTypeParams(sig)
-			for i := 0; i < rparams.Len(); i++ {
-				rparam := rparams.At(i)
-				name := obj.Name() + "." + m.Name() + "." + rparam.Obj().Name()
-				w.p.tparamNames[rparam.Obj()] = name
-			}
-			w.param(sig.Recv())
-			w.signature(sig)
-		}
-
-	default:
-		panic(internalErrorf("unexpected object: %v", obj))
-	}
-
-	p.declIndex[obj] = w.flush()
-}
-
-func (w *exportWriter) tag(tag byte) {
-	w.data.WriteByte(tag)
-}
-
-func (w *exportWriter) pos(pos token.Pos) {
-	if w.p.version >= iexportVersionPosCol {
-		w.posV1(pos)
-	} else {
-		w.posV0(pos)
-	}
-}
-
-func (w *exportWriter) posV1(pos token.Pos) {
-	if w.p.fset == nil {
-		w.int64(0)
-		return
-	}
-
-	p := w.p.fset.Position(pos)
-	file := p.Filename
-	line := int64(p.Line)
-	column := int64(p.Column)
-
-	deltaColumn := (column - w.prevColumn) << 1
-	deltaLine := (line - w.prevLine) << 1
-
-	if file != w.prevFile {
-		deltaLine |= 1
-	}
-	if deltaLine != 0 {
-		deltaColumn |= 1
-	}
-
-	w.int64(deltaColumn)
-	if deltaColumn&1 != 0 {
-		w.int64(deltaLine)
-		if deltaLine&1 != 0 {
-			w.string(file)
-		}
-	}
-
-	w.prevFile = file
-	w.prevLine = line
-	w.prevColumn = column
-}
-
-func (w *exportWriter) posV0(pos token.Pos) {
-	if w.p.fset == nil {
-		w.int64(0)
-		return
-	}
-
-	p := w.p.fset.Position(pos)
-	file := p.Filename
-	line := int64(p.Line)
-
-	// When file is the same as the last position (common case),
-	// we can save a few bytes by delta encoding just the line
-	// number.
-	//
-	// Note: Because data objects may be read out of order (or not
-	// at all), we can only apply delta encoding within a single
-	// object. This is handled implicitly by tracking prevFile and
-	// prevLine as fields of exportWriter.
-
-	if file == w.prevFile {
-		delta := line - w.prevLine
-		w.int64(delta)
-		if delta == deltaNewFile {
-			w.int64(-1)
-		}
-	} else {
-		w.int64(deltaNewFile)
-		w.int64(line) // line >= 0
-		w.string(file)
-		w.prevFile = file
-	}
-	w.prevLine = line
-}
-
-func (w *exportWriter) pkg(pkg *types.Package) {
-	// Ensure any referenced packages are declared in the main index.
-	w.p.allPkgs[pkg] = true
-
-	w.string(w.exportPath(pkg))
-}
-
-func (w *exportWriter) qualifiedIdent(obj types.Object) {
-	name := w.p.indexName(obj)
-
-	// Ensure any referenced declarations are written out too.
-	w.p.pushDecl(obj)
-	w.string(name)
-	w.pkg(obj.Pkg())
-}
-
-func (w *exportWriter) typ(t types.Type, pkg *types.Package) {
-	w.data.uint64(w.p.typOff(t, pkg))
-}
-
-func (p *iexporter) newWriter() *exportWriter {
-	return &exportWriter{p: p}
-}
-
-func (w *exportWriter) flush() uint64 {
-	off := uint64(w.p.data0.Len())
-	io.Copy(&w.p.data0, &w.data)
-	return off
-}
-
-func (p *iexporter) typOff(t types.Type, pkg *types.Package) uint64 {
-	off, ok := p.typIndex[t]
-	if !ok {
-		w := p.newWriter()
-		w.doTyp(t, pkg)
-		off = predeclReserved + w.flush()
-		p.typIndex[t] = off
-	}
-	return off
-}
-
-func (w *exportWriter) startType(k itag) {
-	w.data.uint64(uint64(k))
-}
-
-func (w *exportWriter) doTyp(t types.Type, pkg *types.Package) {
-	if trace {
-		w.p.trace("exporting type %s (%T)", t, t)
-		w.p.indent++
-		defer func() {
-			w.p.indent--
-			w.p.trace("=> %s", t)
-		}()
-	}
-	switch t := t.(type) {
-	case *types.Named:
-		if targs := typeparams.NamedTypeArgs(t); targs.Len() > 0 {
-			w.startType(instanceType)
-			// TODO(rfindley): investigate if this position is correct, and if it
-			// matters.
-			w.pos(t.Obj().Pos())
-			w.typeList(targs, pkg)
-			w.typ(typeparams.NamedTypeOrigin(t), pkg)
-			return
-		}
-		w.startType(definedType)
-		w.qualifiedIdent(t.Obj())
-
-	case *typeparams.TypeParam:
-		w.startType(typeParamType)
-		w.qualifiedIdent(t.Obj())
-
-	case *types.Pointer:
-		w.startType(pointerType)
-		w.typ(t.Elem(), pkg)
-
-	case *types.Slice:
-		w.startType(sliceType)
-		w.typ(t.Elem(), pkg)
-
-	case *types.Array:
-		w.startType(arrayType)
-		w.uint64(uint64(t.Len()))
-		w.typ(t.Elem(), pkg)
-
-	case *types.Chan:
-		w.startType(chanType)
-		// 1 RecvOnly; 2 SendOnly; 3 SendRecv
-		var dir uint64
-		switch t.Dir() {
-		case types.RecvOnly:
-			dir = 1
-		case types.SendOnly:
-			dir = 2
-		case types.SendRecv:
-			dir = 3
-		}
-		w.uint64(dir)
-		w.typ(t.Elem(), pkg)
-
-	case *types.Map:
-		w.startType(mapType)
-		w.typ(t.Key(), pkg)
-		w.typ(t.Elem(), pkg)
-
-	case *types.Signature:
-		w.startType(signatureType)
-		w.setPkg(pkg, true)
-		w.signature(t)
-
-	case *types.Struct:
-		w.startType(structType)
-		w.setPkg(pkg, true)
-
-		n := t.NumFields()
-		w.uint64(uint64(n))
-		for i := 0; i < n; i++ {
-			f := t.Field(i)
-			w.pos(f.Pos())
-			w.string(f.Name())
-			w.typ(f.Type(), pkg)
-			w.bool(f.Anonymous())
-			w.string(t.Tag(i)) // note (or tag)
-		}
-
-	case *types.Interface:
-		w.startType(interfaceType)
-		w.setPkg(pkg, true)
-
-		n := t.NumEmbeddeds()
-		w.uint64(uint64(n))
-		for i := 0; i < n; i++ {
-			ft := t.EmbeddedType(i)
-			tPkg := pkg
-			if named, _ := ft.(*types.Named); named != nil {
-				w.pos(named.Obj().Pos())
-			} else {
-				w.pos(token.NoPos)
-			}
-			w.typ(ft, tPkg)
-		}
-
-		n = t.NumExplicitMethods()
-		w.uint64(uint64(n))
-		for i := 0; i < n; i++ {
-			m := t.ExplicitMethod(i)
-			w.pos(m.Pos())
-			w.string(m.Name())
-			sig, _ := m.Type().(*types.Signature)
-			w.signature(sig)
-		}
-
-	case *typeparams.Union:
-		w.startType(unionType)
-		nt := t.Len()
-		w.uint64(uint64(nt))
-		for i := 0; i < nt; i++ {
-			term := t.Term(i)
-			w.bool(term.Tilde())
-			w.typ(term.Type(), pkg)
-		}
-
-	default:
-		panic(internalErrorf("unexpected type: %v, %v", t, reflect.TypeOf(t)))
-	}
-}
-
-func (w *exportWriter) setPkg(pkg *types.Package, write bool) {
-	if write {
-		w.pkg(pkg)
-	}
-
-	w.currPkg = pkg
-}
-
-func (w *exportWriter) signature(sig *types.Signature) {
-	w.paramList(sig.Params())
-	w.paramList(sig.Results())
-	if sig.Params().Len() > 0 {
-		w.bool(sig.Variadic())
-	}
-}
-
-func (w *exportWriter) typeList(ts *typeparams.TypeList, pkg *types.Package) {
-	w.uint64(uint64(ts.Len()))
-	for i := 0; i < ts.Len(); i++ {
-		w.typ(ts.At(i), pkg)
-	}
-}
-
-func (w *exportWriter) tparamList(owner types.Object, list *typeparams.TypeParamList, pkg *types.Package) {
-	ll := uint64(list.Len())
-	w.uint64(ll)
-	for i := 0; i < list.Len(); i++ {
-		tparam := list.At(i)
-		// Qualify the type parameter name before exporting its type.
-		name := owner.Name() + "." + tparam.Obj().Name()
-		w.p.tparamNames[tparam.Obj()] = name
-		w.typ(list.At(i), pkg)
-	}
-}
-
-func (w *exportWriter) paramList(tup *types.Tuple) {
-	n := tup.Len()
-	w.uint64(uint64(n))
-	for i := 0; i < n; i++ {
-		w.param(tup.At(i))
-	}
-}
-
-func (w *exportWriter) param(obj types.Object) {
-	w.pos(obj.Pos())
-	w.localIdent(obj)
-	w.typ(obj.Type(), obj.Pkg())
-}
-
-func (w *exportWriter) value(typ types.Type, v constant.Value) {
-	w.typ(typ, nil)
-	if w.p.version >= iexportVersionGo1_18 {
-		w.int64(int64(v.Kind()))
-	}
-
-	switch b := typ.Underlying().(*types.Basic); b.Info() & types.IsConstType {
-	case types.IsBoolean:
-		w.bool(constant.BoolVal(v))
-	case types.IsInteger:
-		var i big.Int
-		if i64, exact := constant.Int64Val(v); exact {
-			i.SetInt64(i64)
-		} else if ui64, exact := constant.Uint64Val(v); exact {
-			i.SetUint64(ui64)
-		} else {
-			i.SetString(v.ExactString(), 10)
-		}
-		w.mpint(&i, typ)
-	case types.IsFloat:
-		f := constantToFloat(v)
-		w.mpfloat(f, typ)
-	case types.IsComplex:
-		w.mpfloat(constantToFloat(constant.Real(v)), typ)
-		w.mpfloat(constantToFloat(constant.Imag(v)), typ)
-	case types.IsString:
-		w.string(constant.StringVal(v))
-	default:
-		if b.Kind() == types.Invalid {
-			// package contains type errors
-			break
-		}
-		panic(internalErrorf("unexpected type %v (%v)", typ, typ.Underlying()))
-	}
-}
-
-// constantToFloat converts a constant.Value with kind constant.Float to a
-// big.Float.
-func constantToFloat(x constant.Value) *big.Float {
-	x = constant.ToFloat(x)
-	// Use the same floating-point precision (512) as cmd/compile
-	// (see Mpprec in cmd/compile/internal/gc/mpfloat.go).
-	const mpprec = 512
-	var f big.Float
-	f.SetPrec(mpprec)
-	if v, exact := constant.Float64Val(x); exact {
-		// float64
-		f.SetFloat64(v)
-	} else if num, denom := constant.Num(x), constant.Denom(x); num.Kind() == constant.Int {
-		// TODO(gri): add big.Rat accessor to constant.Value.
-		n := valueToRat(num)
-		d := valueToRat(denom)
-		f.SetRat(n.Quo(n, d))
-	} else {
-		// Value too large to represent as a fraction => inaccessible.
-		// TODO(gri): add big.Float accessor to constant.Value.
-		_, ok := f.SetString(x.ExactString())
-		assert(ok)
-	}
-	return &f
-}
-
-// mpint exports a multi-precision integer.
-//
-// For unsigned types, small values are written out as a single
-// byte. Larger values are written out as a length-prefixed big-endian
-// byte string, where the length prefix is encoded as its complement.
-// For example, bytes 0, 1, and 2 directly represent the integer
-// values 0, 1, and 2; while bytes 255, 254, and 253 indicate a 1-,
-// 2-, and 3-byte big-endian string follow.
-//
-// Encoding for signed types use the same general approach as for
-// unsigned types, except small values use zig-zag encoding and the
-// bottom bit of length prefix byte for large values is reserved as a
-// sign bit.
-//
-// The exact boundary between small and large encodings varies
-// according to the maximum number of bytes needed to encode a value
-// of type typ. As a special case, 8-bit types are always encoded as a
-// single byte.
-//
-// TODO(mdempsky): Is this level of complexity really worthwhile?
-func (w *exportWriter) mpint(x *big.Int, typ types.Type) {
-	basic, ok := typ.Underlying().(*types.Basic)
-	if !ok {
-		panic(internalErrorf("unexpected type %v (%T)", typ.Underlying(), typ.Underlying()))
-	}
-
-	signed, maxBytes := intSize(basic)
-
-	negative := x.Sign() < 0
-	if !signed && negative {
-		panic(internalErrorf("negative unsigned integer; type %v, value %v", typ, x))
-	}
-
-	b := x.Bytes()
-	if len(b) > 0 && b[0] == 0 {
-		panic(internalErrorf("leading zeros"))
-	}
-	if uint(len(b)) > maxBytes {
-		panic(internalErrorf("bad mpint length: %d > %d (type %v, value %v)", len(b), maxBytes, typ, x))
-	}
-
-	maxSmall := 256 - maxBytes
-	if signed {
-		maxSmall = 256 - 2*maxBytes
-	}
-	if maxBytes == 1 {
-		maxSmall = 256
-	}
-
-	// Check if x can use small value encoding.
-	if len(b) <= 1 {
-		var ux uint
-		if len(b) == 1 {
-			ux = uint(b[0])
-		}
-		if signed {
-			ux <<= 1
-			if negative {
-				ux--
-			}
-		}
-		if ux < maxSmall {
-			w.data.WriteByte(byte(ux))
-			return
-		}
-	}
-
-	n := 256 - uint(len(b))
-	if signed {
-		n = 256 - 2*uint(len(b))
-		if negative {
-			n |= 1
-		}
-	}
-	if n < maxSmall || n >= 256 {
-		panic(internalErrorf("encoding mistake: %d, %v, %v => %d", len(b), signed, negative, n))
-	}
-
-	w.data.WriteByte(byte(n))
-	w.data.Write(b)
-}
-
-// mpfloat exports a multi-precision floating point number.
-//
-// The number's value is decomposed into mantissa × 2**exponent, where
-// mantissa is an integer. The value is written out as mantissa (as a
-// multi-precision integer) and then the exponent, except exponent is
-// omitted if mantissa is zero.
-func (w *exportWriter) mpfloat(f *big.Float, typ types.Type) {
-	if f.IsInf() {
-		panic("infinite constant")
-	}
-
-	// Break into f = mant × 2**exp, with 0.5 <= mant < 1.
-	var mant big.Float
-	exp := int64(f.MantExp(&mant))
-
-	// Scale so that mant is an integer.
-	prec := mant.MinPrec()
-	mant.SetMantExp(&mant, int(prec))
-	exp -= int64(prec)
-
-	manti, acc := mant.Int(nil)
-	if acc != big.Exact {
-		panic(internalErrorf("mantissa scaling failed for %f (%s)", f, acc))
-	}
-	w.mpint(manti, typ)
-	if manti.Sign() != 0 {
-		w.int64(exp)
-	}
-}
-
-func (w *exportWriter) bool(b bool) bool {
-	var x uint64
-	if b {
-		x = 1
-	}
-	w.uint64(x)
-	return b
-}
-
-func (w *exportWriter) int64(x int64)   { w.data.int64(x) }
-func (w *exportWriter) uint64(x uint64) { w.data.uint64(x) }
-func (w *exportWriter) string(s string) { w.uint64(w.p.stringOff(s)) }
-
-func (w *exportWriter) localIdent(obj types.Object) {
-	// Anonymous parameters.
-	if obj == nil {
-		w.string("")
-		return
-	}
-
-	name := obj.Name()
-	if name == "_" {
-		w.string("_")
-		return
-	}
-
-	w.string(name)
-}
-
-type intWriter struct {
-	bytes.Buffer
-}
-
-func (w *intWriter) int64(x int64) {
-	var buf [binary.MaxVarintLen64]byte
-	n := binary.PutVarint(buf[:], x)
-	w.Write(buf[:n])
-}
-
-func (w *intWriter) uint64(x uint64) {
-	var buf [binary.MaxVarintLen64]byte
-	n := binary.PutUvarint(buf[:], x)
-	w.Write(buf[:n])
-}
-
-func assert(cond bool) {
-	if !cond {
-		panic("internal error: assertion failed")
-	}
-}
-
-// The below is copied from go/src/cmd/compile/internal/gc/syntax.go.
-
-// objQueue is a FIFO queue of types.Object. The zero value of objQueue is
-// a ready-to-use empty queue.
-type objQueue struct {
-	ring       []types.Object
-	head, tail int
-}
-
-// empty returns true if q contains no Nodes.
-func (q *objQueue) empty() bool {
-	return q.head == q.tail
-}
-
-// pushTail appends n to the tail of the queue.
-func (q *objQueue) pushTail(obj types.Object) {
-	if len(q.ring) == 0 {
-		q.ring = make([]types.Object, 16)
-	} else if q.head+len(q.ring) == q.tail {
-		// Grow the ring.
-		nring := make([]types.Object, len(q.ring)*2)
-		// Copy the old elements.
-		part := q.ring[q.head%len(q.ring):]
-		if q.tail-q.head <= len(part) {
-			part = part[:q.tail-q.head]
-			copy(nring, part)
-		} else {
-			pos := copy(nring, part)
-			copy(nring[pos:], q.ring[:q.tail%len(q.ring)])
-		}
-		q.ring, q.head, q.tail = nring, 0, q.tail-q.head
-	}
-
-	q.ring[q.tail%len(q.ring)] = obj
-	q.tail++
-}
-
-// popHead pops a node from the head of the queue. It panics if q is empty.
-func (q *objQueue) popHead() types.Object {
-	if q.empty() {
-		panic("dequeue empty")
-	}
-	obj := q.ring[q.head%len(q.ring)]
-	q.head++
-	return obj
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go
deleted file mode 100644
index cdb332c..0000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/iimport.go
+++ /dev/null
@@ -1,889 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Indexed package import.
-// See cmd/compile/internal/gc/iexport.go for the export data format.
-
-// This file is a copy of $GOROOT/src/go/internal/gcimporter/iimport.go.
-
-package gcimporter
-
-import (
-	"bytes"
-	"encoding/binary"
-	"fmt"
-	"go/constant"
-	"go/token"
-	"go/types"
-	"io"
-	"sort"
-	"strings"
-
-	"golang.org/x/tools/internal/typeparams"
-)
-
-type intReader struct {
-	*bytes.Reader
-	path string
-}
-
-func (r *intReader) int64() int64 {
-	i, err := binary.ReadVarint(r.Reader)
-	if err != nil {
-		errorf("import %q: read varint error: %v", r.path, err)
-	}
-	return i
-}
-
-func (r *intReader) uint64() uint64 {
-	i, err := binary.ReadUvarint(r.Reader)
-	if err != nil {
-		errorf("import %q: read varint error: %v", r.path, err)
-	}
-	return i
-}
-
-// Keep this in sync with constants in iexport.go.
-//
-// Temporarily, the x/tools importer accepts generic code at both version 1 and
-// 2. However, version 2 contains some breaking changes on top of version 1:
-//   - the 'implicit' bit is added to exported constraints
-//   - a 'kind' byte is added to constant values (not yet done)
-//
-// Once we've completed the bump to version 2 in the standard library, we'll
-// remove support for generics here at version 1.
-const (
-	iexportVersionGo1_11 = 0
-	iexportVersionPosCol = 1
-	iexportVersionGo1_18 = 2
-	// TODO: before release, change this back to 2.
-	iexportVersionGenerics = iexportVersionPosCol
-)
-
-type ident struct {
-	pkg  string
-	name string
-}
-
-const predeclReserved = 32
-
-type itag uint64
-
-const (
-	// Types
-	definedType itag = iota
-	pointerType
-	sliceType
-	arrayType
-	chanType
-	mapType
-	signatureType
-	structType
-	interfaceType
-	typeParamType
-	instanceType
-	unionType
-)
-
-// IImportData imports a package from the serialized package data
-// and returns 0 and a reference to the package.
-// If the export data version is not recognized or the format is otherwise
-// compromised, an error is returned.
-func IImportData(fset *token.FileSet, imports map[string]*types.Package, data []byte, path string) (int, *types.Package, error) {
-	pkgs, err := iimportCommon(fset, imports, data, false, path)
-	if err != nil {
-		return 0, nil, err
-	}
-	return 0, pkgs[0], nil
-}
-
-// IImportBundle imports a set of packages from the serialized package bundle.
-func IImportBundle(fset *token.FileSet, imports map[string]*types.Package, data []byte) ([]*types.Package, error) {
-	return iimportCommon(fset, imports, data, true, "")
-}
-
-func iimportCommon(fset *token.FileSet, imports map[string]*types.Package, data []byte, bundle bool, path string) (pkgs []*types.Package, err error) {
-	const currentVersion = 1
-	version := int64(-1)
-	if !debug {
-		defer func() {
-			if e := recover(); e != nil {
-				if version > currentVersion {
-					err = fmt.Errorf("cannot import %q (%v), export data is newer version - update tool", path, e)
-				} else {
-					err = fmt.Errorf("cannot import %q (%v), possibly version skew - reinstall package", path, e)
-				}
-			}
-		}()
-	}
-
-	r := &intReader{bytes.NewReader(data), path}
-
-	if bundle {
-		bundleVersion := r.uint64()
-		switch bundleVersion {
-		case bundleVersion:
-		default:
-			errorf("unknown bundle format version %d", bundleVersion)
-		}
-	}
-
-	version = int64(r.uint64())
-	switch version {
-	case iexportVersionGo1_18, iexportVersionPosCol, iexportVersionGo1_11:
-	default:
-		if version > iexportVersionGo1_18 {
-			errorf("unstable iexport format version %d, just rebuild compiler and std library", version)
-		} else {
-			errorf("unknown iexport format version %d", version)
-		}
-	}
-
-	sLen := int64(r.uint64())
-	dLen := int64(r.uint64())
-
-	whence, _ := r.Seek(0, io.SeekCurrent)
-	stringData := data[whence : whence+sLen]
-	declData := data[whence+sLen : whence+sLen+dLen]
-	r.Seek(sLen+dLen, io.SeekCurrent)
-
-	p := iimporter{
-		version: int(version),
-		ipath:   path,
-
-		stringData:  stringData,
-		stringCache: make(map[uint64]string),
-		pkgCache:    make(map[uint64]*types.Package),
-
-		declData: declData,
-		pkgIndex: make(map[*types.Package]map[string]uint64),
-		typCache: make(map[uint64]types.Type),
-		// Separate map for typeparams, keyed by their package and unique
-		// name.
-		tparamIndex: make(map[ident]types.Type),
-
-		fake: fakeFileSet{
-			fset:  fset,
-			files: make(map[string]*fileInfo),
-		},
-	}
-	defer p.fake.setLines() // set lines for files in fset
-
-	for i, pt := range predeclared() {
-		p.typCache[uint64(i)] = pt
-	}
-
-	pkgList := make([]*types.Package, r.uint64())
-	for i := range pkgList {
-		pkgPathOff := r.uint64()
-		pkgPath := p.stringAt(pkgPathOff)
-		pkgName := p.stringAt(r.uint64())
-		_ = r.uint64() // package height; unused by go/types
-
-		if pkgPath == "" {
-			pkgPath = path
-		}
-		pkg := imports[pkgPath]
-		if pkg == nil {
-			pkg = types.NewPackage(pkgPath, pkgName)
-			imports[pkgPath] = pkg
-		} else if pkg.Name() != pkgName {
-			errorf("conflicting names %s and %s for package %q", pkg.Name(), pkgName, path)
-		}
-
-		p.pkgCache[pkgPathOff] = pkg
-
-		nameIndex := make(map[string]uint64)
-		for nSyms := r.uint64(); nSyms > 0; nSyms-- {
-			name := p.stringAt(r.uint64())
-			nameIndex[name] = r.uint64()
-		}
-
-		p.pkgIndex[pkg] = nameIndex
-		pkgList[i] = pkg
-	}
-
-	if bundle {
-		pkgs = make([]*types.Package, r.uint64())
-		for i := range pkgs {
-			pkg := p.pkgAt(r.uint64())
-			imps := make([]*types.Package, r.uint64())
-			for j := range imps {
-				imps[j] = p.pkgAt(r.uint64())
-			}
-			pkg.SetImports(imps)
-			pkgs[i] = pkg
-		}
-	} else {
-		if len(pkgList) == 0 {
-			errorf("no packages found for %s", path)
-			panic("unreachable")
-		}
-		pkgs = pkgList[:1]
-
-		// record all referenced packages as imports
-		list := append(([]*types.Package)(nil), pkgList[1:]...)
-		sort.Sort(byPath(list))
-		pkgs[0].SetImports(list)
-	}
-
-	for _, pkg := range pkgs {
-		if pkg.Complete() {
-			continue
-		}
-
-		names := make([]string, 0, len(p.pkgIndex[pkg]))
-		for name := range p.pkgIndex[pkg] {
-			names = append(names, name)
-		}
-		sort.Strings(names)
-		for _, name := range names {
-			p.doDecl(pkg, name)
-		}
-
-		// package was imported completely and without errors
-		pkg.MarkComplete()
-	}
-
-	for _, typ := range p.interfaceList {
-		typ.Complete()
-	}
-
-	return pkgs, nil
-}
-
-type iimporter struct {
-	version int
-	ipath   string
-
-	stringData  []byte
-	stringCache map[uint64]string
-	pkgCache    map[uint64]*types.Package
-
-	declData    []byte
-	pkgIndex    map[*types.Package]map[string]uint64
-	typCache    map[uint64]types.Type
-	tparamIndex map[ident]types.Type
-
-	fake          fakeFileSet
-	interfaceList []*types.Interface
-
-	indent int // for tracing support
-}
-
-func (p *iimporter) trace(format string, args ...interface{}) {
-	if !trace {
-		// Call sites should also be guarded, but having this check here allows
-		// easily enabling/disabling debug trace statements.
-		return
-	}
-	fmt.Printf(strings.Repeat("..", p.indent)+format+"\n", args...)
-}
-
-func (p *iimporter) doDecl(pkg *types.Package, name string) {
-	if debug {
-		p.trace("import decl %s", name)
-		p.indent++
-		defer func() {
-			p.indent--
-			p.trace("=> %s", name)
-		}()
-	}
-	// See if we've already imported this declaration.
-	if obj := pkg.Scope().Lookup(name); obj != nil {
-		return
-	}
-
-	off, ok := p.pkgIndex[pkg][name]
-	if !ok {
-		errorf("%v.%v not in index", pkg, name)
-	}
-
-	r := &importReader{p: p, currPkg: pkg}
-	r.declReader.Reset(p.declData[off:])
-
-	r.obj(name)
-}
-
-func (p *iimporter) stringAt(off uint64) string {
-	if s, ok := p.stringCache[off]; ok {
-		return s
-	}
-
-	slen, n := binary.Uvarint(p.stringData[off:])
-	if n <= 0 {
-		errorf("varint failed")
-	}
-	spos := off + uint64(n)
-	s := string(p.stringData[spos : spos+slen])
-	p.stringCache[off] = s
-	return s
-}
-
-func (p *iimporter) pkgAt(off uint64) *types.Package {
-	if pkg, ok := p.pkgCache[off]; ok {
-		return pkg
-	}
-	path := p.stringAt(off)
-	errorf("missing package %q in %q", path, p.ipath)
-	return nil
-}
-
-func (p *iimporter) typAt(off uint64, base *types.Named) types.Type {
-	if t, ok := p.typCache[off]; ok && canReuse(base, t) {
-		return t
-	}
-
-	if off < predeclReserved {
-		errorf("predeclared type missing from cache: %v", off)
-	}
-
-	r := &importReader{p: p}
-	r.declReader.Reset(p.declData[off-predeclReserved:])
-	t := r.doType(base)
-
-	if canReuse(base, t) {
-		p.typCache[off] = t
-	}
-	return t
-}
-
-// canReuse reports whether the type rhs on the RHS of the declaration for def
-// may be re-used.
-//
-// Specifically, if def is non-nil and rhs is an interface type with methods, it
-// may not be re-used because we have a convention of setting the receiver type
-// for interface methods to def.
-func canReuse(def *types.Named, rhs types.Type) bool {
-	if def == nil {
-		return true
-	}
-	iface, _ := rhs.(*types.Interface)
-	if iface == nil {
-		return true
-	}
-	// Don't use iface.Empty() here as iface may not be complete.
-	return iface.NumEmbeddeds() == 0 && iface.NumExplicitMethods() == 0
-}
-
-type importReader struct {
-	p          *iimporter
-	declReader bytes.Reader
-	currPkg    *types.Package
-	prevFile   string
-	prevLine   int64
-	prevColumn int64
-}
-
-func (r *importReader) obj(name string) {
-	tag := r.byte()
-	pos := r.pos()
-
-	switch tag {
-	case 'A':
-		typ := r.typ()
-
-		r.declare(types.NewTypeName(pos, r.currPkg, name, typ))
-
-	case 'C':
-		typ, val := r.value()
-
-		r.declare(types.NewConst(pos, r.currPkg, name, typ, val))
-
-	case 'F', 'G':
-		var tparams []*typeparams.TypeParam
-		if tag == 'G' {
-			tparams = r.tparamList()
-		}
-		sig := r.signature(nil, nil, tparams)
-		r.declare(types.NewFunc(pos, r.currPkg, name, sig))
-
-	case 'T', 'U':
-		// Types can be recursive. We need to setup a stub
-		// declaration before recursing.
-		obj := types.NewTypeName(pos, r.currPkg, name, nil)
-		named := types.NewNamed(obj, nil, nil)
-		// Declare obj before calling r.tparamList, so the new type name is recognized
-		// if used in the constraint of one of its own typeparams (see #48280).
-		r.declare(obj)
-		if tag == 'U' {
-			tparams := r.tparamList()
-			typeparams.SetForNamed(named, tparams)
-		}
-
-		underlying := r.p.typAt(r.uint64(), named).Underlying()
-		named.SetUnderlying(underlying)
-
-		if !isInterface(underlying) {
-			for n := r.uint64(); n > 0; n-- {
-				mpos := r.pos()
-				mname := r.ident()
-				recv := r.param()
-
-				// If the receiver has any targs, set those as the
-				// rparams of the method (since those are the
-				// typeparams being used in the method sig/body).
-				base := baseType(recv.Type())
-				assert(base != nil)
-				targs := typeparams.NamedTypeArgs(base)
-				var rparams []*typeparams.TypeParam
-				if targs.Len() > 0 {
-					rparams = make([]*typeparams.TypeParam, targs.Len())
-					for i := range rparams {
-						rparams[i] = targs.At(i).(*typeparams.TypeParam)
-					}
-				}
-				msig := r.signature(recv, rparams, nil)
-
-				named.AddMethod(types.NewFunc(mpos, r.currPkg, mname, msig))
-			}
-		}
-
-	case 'P':
-		// We need to "declare" a typeparam in order to have a name that
-		// can be referenced recursively (if needed) in the type param's
-		// bound.
-		if r.p.version < iexportVersionGenerics {
-			errorf("unexpected type param type")
-		}
-		// Remove the "path" from the type param name that makes it unique
-		ix := strings.LastIndex(name, ".")
-		if ix < 0 {
-			errorf("missing path for type param")
-		}
-		name0 := name[ix+1:]
-		tn := types.NewTypeName(pos, r.currPkg, name0, nil)
-		t := typeparams.NewTypeParam(tn, nil)
-
-		// To handle recursive references to the typeparam within its
-		// bound, save the partial type in tparamIndex before reading the bounds.
-		id := ident{r.currPkg.Name(), name}
-		r.p.tparamIndex[id] = t
-		var implicit bool
-		if r.p.version >= iexportVersionGo1_18 {
-			implicit = r.bool()
-		}
-		constraint := r.typ()
-		if implicit {
-			iface, _ := constraint.(*types.Interface)
-			if iface == nil {
-				errorf("non-interface constraint marked implicit")
-			}
-			typeparams.MarkImplicit(iface)
-		}
-		typeparams.SetTypeParamConstraint(t, constraint)
-
-	case 'V':
-		typ := r.typ()
-
-		r.declare(types.NewVar(pos, r.currPkg, name, typ))
-
-	default:
-		errorf("unexpected tag: %v", tag)
-	}
-}
-
-func (r *importReader) declare(obj types.Object) {
-	obj.Pkg().Scope().Insert(obj)
-}
-
-func (r *importReader) value() (typ types.Type, val constant.Value) {
-	typ = r.typ()
-	if r.p.version >= iexportVersionGo1_18 {
-		// TODO: add support for using the kind.
-		_ = constant.Kind(r.int64())
-	}
-
-	switch b := typ.Underlying().(*types.Basic); b.Info() & types.IsConstType {
-	case types.IsBoolean:
-		val = constant.MakeBool(r.bool())
-
-	case types.IsString:
-		val = constant.MakeString(r.string())
-
-	case types.IsInteger:
-		val = r.mpint(b)
-
-	case types.IsFloat:
-		val = r.mpfloat(b)
-
-	case types.IsComplex:
-		re := r.mpfloat(b)
-		im := r.mpfloat(b)
-		val = constant.BinaryOp(re, token.ADD, constant.MakeImag(im))
-
-	default:
-		if b.Kind() == types.Invalid {
-			val = constant.MakeUnknown()
-			return
-		}
-		errorf("unexpected type %v", typ) // panics
-		panic("unreachable")
-	}
-
-	return
-}
-
-func intSize(b *types.Basic) (signed bool, maxBytes uint) {
-	if (b.Info() & types.IsUntyped) != 0 {
-		return true, 64
-	}
-
-	switch b.Kind() {
-	case types.Float32, types.Complex64:
-		return true, 3
-	case types.Float64, types.Complex128:
-		return true, 7
-	}
-
-	signed = (b.Info() & types.IsUnsigned) == 0
-	switch b.Kind() {
-	case types.Int8, types.Uint8:
-		maxBytes = 1
-	case types.Int16, types.Uint16:
-		maxBytes = 2
-	case types.Int32, types.Uint32:
-		maxBytes = 4
-	default:
-		maxBytes = 8
-	}
-
-	return
-}
-
-func (r *importReader) mpint(b *types.Basic) constant.Value {
-	signed, maxBytes := intSize(b)
-
-	maxSmall := 256 - maxBytes
-	if signed {
-		maxSmall = 256 - 2*maxBytes
-	}
-	if maxBytes == 1 {
-		maxSmall = 256
-	}
-
-	n, _ := r.declReader.ReadByte()
-	if uint(n) < maxSmall {
-		v := int64(n)
-		if signed {
-			v >>= 1
-			if n&1 != 0 {
-				v = ^v
-			}
-		}
-		return constant.MakeInt64(v)
-	}
-
-	v := -n
-	if signed {
-		v = -(n &^ 1) >> 1
-	}
-	if v < 1 || uint(v) > maxBytes {
-		errorf("weird decoding: %v, %v => %v", n, signed, v)
-	}
-
-	buf := make([]byte, v)
-	io.ReadFull(&r.declReader, buf)
-
-	// convert to little endian
-	// TODO(gri) go/constant should have a more direct conversion function
-	//           (e.g., once it supports a big.Float based implementation)
-	for i, j := 0, len(buf)-1; i < j; i, j = i+1, j-1 {
-		buf[i], buf[j] = buf[j], buf[i]
-	}
-
-	x := constant.MakeFromBytes(buf)
-	if signed && n&1 != 0 {
-		x = constant.UnaryOp(token.SUB, x, 0)
-	}
-	return x
-}
-
-func (r *importReader) mpfloat(b *types.Basic) constant.Value {
-	x := r.mpint(b)
-	if constant.Sign(x) == 0 {
-		return x
-	}
-
-	exp := r.int64()
-	switch {
-	case exp > 0:
-		x = constant.Shift(x, token.SHL, uint(exp))
-		// Ensure that the imported Kind is Float, else this constant may run into
-		// bitsize limits on overlarge integers. Eventually we can instead adopt
-		// the approach of CL 288632, but that CL relies on go/constant APIs that
-		// were introduced in go1.13.
-		//
-		// TODO(rFindley): sync the logic here with tip Go once we no longer
-		// support go1.12.
-		x = constant.ToFloat(x)
-	case exp < 0:
-		d := constant.Shift(constant.MakeInt64(1), token.SHL, uint(-exp))
-		x = constant.BinaryOp(x, token.QUO, d)
-	}
-	return x
-}
-
-func (r *importReader) ident() string {
-	return r.string()
-}
-
-func (r *importReader) qualifiedIdent() (*types.Package, string) {
-	name := r.string()
-	pkg := r.pkg()
-	return pkg, name
-}
-
-func (r *importReader) pos() token.Pos {
-	if r.p.version >= iexportVersionPosCol {
-		r.posv1()
-	} else {
-		r.posv0()
-	}
-
-	if r.prevFile == "" && r.prevLine == 0 && r.prevColumn == 0 {
-		return token.NoPos
-	}
-	return r.p.fake.pos(r.prevFile, int(r.prevLine), int(r.prevColumn))
-}
-
-func (r *importReader) posv0() {
-	delta := r.int64()
-	if delta != deltaNewFile {
-		r.prevLine += delta
-	} else if l := r.int64(); l == -1 {
-		r.prevLine += deltaNewFile
-	} else {
-		r.prevFile = r.string()
-		r.prevLine = l
-	}
-}
-
-func (r *importReader) posv1() {
-	delta := r.int64()
-	r.prevColumn += delta >> 1
-	if delta&1 != 0 {
-		delta = r.int64()
-		r.prevLine += delta >> 1
-		if delta&1 != 0 {
-			r.prevFile = r.string()
-		}
-	}
-}
-
-func (r *importReader) typ() types.Type {
-	return r.p.typAt(r.uint64(), nil)
-}
-
-func isInterface(t types.Type) bool {
-	_, ok := t.(*types.Interface)
-	return ok
-}
-
-func (r *importReader) pkg() *types.Package { return r.p.pkgAt(r.uint64()) }
-func (r *importReader) string() string      { return r.p.stringAt(r.uint64()) }
-
-func (r *importReader) doType(base *types.Named) (res types.Type) {
-	k := r.kind()
-	if debug {
-		r.p.trace("importing type %d (base: %s)", k, base)
-		r.p.indent++
-		defer func() {
-			r.p.indent--
-			r.p.trace("=> %s", res)
-		}()
-	}
-	switch k {
-	default:
-		errorf("unexpected kind tag in %q: %v", r.p.ipath, k)
-		return nil
-
-	case definedType:
-		pkg, name := r.qualifiedIdent()
-		r.p.doDecl(pkg, name)
-		return pkg.Scope().Lookup(name).(*types.TypeName).Type()
-	case pointerType:
-		return types.NewPointer(r.typ())
-	case sliceType:
-		return types.NewSlice(r.typ())
-	case arrayType:
-		n := r.uint64()
-		return types.NewArray(r.typ(), int64(n))
-	case chanType:
-		dir := chanDir(int(r.uint64()))
-		return types.NewChan(dir, r.typ())
-	case mapType:
-		return types.NewMap(r.typ(), r.typ())
-	case signatureType:
-		r.currPkg = r.pkg()
-		return r.signature(nil, nil, nil)
-
-	case structType:
-		r.currPkg = r.pkg()
-
-		fields := make([]*types.Var, r.uint64())
-		tags := make([]string, len(fields))
-		for i := range fields {
-			fpos := r.pos()
-			fname := r.ident()
-			ftyp := r.typ()
-			emb := r.bool()
-			tag := r.string()
-
-			fields[i] = types.NewField(fpos, r.currPkg, fname, ftyp, emb)
-			tags[i] = tag
-		}
-		return types.NewStruct(fields, tags)
-
-	case interfaceType:
-		r.currPkg = r.pkg()
-
-		embeddeds := make([]types.Type, r.uint64())
-		for i := range embeddeds {
-			_ = r.pos()
-			embeddeds[i] = r.typ()
-		}
-
-		methods := make([]*types.Func, r.uint64())
-		for i := range methods {
-			mpos := r.pos()
-			mname := r.ident()
-
-			// TODO(mdempsky): Matches bimport.go, but I
-			// don't agree with this.
-			var recv *types.Var
-			if base != nil {
-				recv = types.NewVar(token.NoPos, r.currPkg, "", base)
-			}
-
-			msig := r.signature(recv, nil, nil)
-			methods[i] = types.NewFunc(mpos, r.currPkg, mname, msig)
-		}
-
-		typ := newInterface(methods, embeddeds)
-		r.p.interfaceList = append(r.p.interfaceList, typ)
-		return typ
-
-	case typeParamType:
-		if r.p.version < iexportVersionGenerics {
-			errorf("unexpected type param type")
-		}
-		pkg, name := r.qualifiedIdent()
-		id := ident{pkg.Name(), name}
-		if t, ok := r.p.tparamIndex[id]; ok {
-			// We're already in the process of importing this typeparam.
-			return t
-		}
-		// Otherwise, import the definition of the typeparam now.
-		r.p.doDecl(pkg, name)
-		return r.p.tparamIndex[id]
-
-	case instanceType:
-		if r.p.version < iexportVersionGenerics {
-			errorf("unexpected instantiation type")
-		}
-		// pos does not matter for instances: they are positioned on the original
-		// type.
-		_ = r.pos()
-		len := r.uint64()
-		targs := make([]types.Type, len)
-		for i := range targs {
-			targs[i] = r.typ()
-		}
-		baseType := r.typ()
-		// The imported instantiated type doesn't include any methods, so
-		// we must always use the methods of the base (orig) type.
-		// TODO provide a non-nil *Environment
-		t, _ := typeparams.Instantiate(nil, baseType, targs, false)
-		return t
-
-	case unionType:
-		if r.p.version < iexportVersionGenerics {
-			errorf("unexpected instantiation type")
-		}
-		terms := make([]*typeparams.Term, r.uint64())
-		for i := range terms {
-			terms[i] = typeparams.NewTerm(r.bool(), r.typ())
-		}
-		return typeparams.NewUnion(terms)
-	}
-}
-
-func (r *importReader) kind() itag {
-	return itag(r.uint64())
-}
-
-func (r *importReader) signature(recv *types.Var, rparams []*typeparams.TypeParam, tparams []*typeparams.TypeParam) *types.Signature {
-	params := r.paramList()
-	results := r.paramList()
-	variadic := params.Len() > 0 && r.bool()
-	return typeparams.NewSignatureType(recv, rparams, tparams, params, results, variadic)
-}
-
-func (r *importReader) tparamList() []*typeparams.TypeParam {
-	n := r.uint64()
-	if n == 0 {
-		return nil
-	}
-	xs := make([]*typeparams.TypeParam, n)
-	for i := range xs {
-		// Note: the standard library importer is tolerant of nil types here,
-		// though would panic in SetTypeParams.
-		xs[i] = r.typ().(*typeparams.TypeParam)
-	}
-	return xs
-}
-
-func (r *importReader) paramList() *types.Tuple {
-	xs := make([]*types.Var, r.uint64())
-	for i := range xs {
-		xs[i] = r.param()
-	}
-	return types.NewTuple(xs...)
-}
-
-func (r *importReader) param() *types.Var {
-	pos := r.pos()
-	name := r.ident()
-	typ := r.typ()
-	return types.NewParam(pos, r.currPkg, name, typ)
-}
-
-func (r *importReader) bool() bool {
-	return r.uint64() != 0
-}
-
-func (r *importReader) int64() int64 {
-	n, err := binary.ReadVarint(&r.declReader)
-	if err != nil {
-		errorf("readVarint: %v", err)
-	}
-	return n
-}
-
-func (r *importReader) uint64() uint64 {
-	n, err := binary.ReadUvarint(&r.declReader)
-	if err != nil {
-		errorf("readUvarint: %v", err)
-	}
-	return n
-}
-
-func (r *importReader) byte() byte {
-	x, err := r.declReader.ReadByte()
-	if err != nil {
-		errorf("declReader.ReadByte: %v", err)
-	}
-	return x
-}
-
-func baseType(typ types.Type) *types.Named {
-	// pointer receivers are never types.Named types
-	if p, _ := typ.(*types.Pointer); p != nil {
-		typ = p.Elem()
-	}
-	// receiver base types are always (possibly generic) types.Named types
-	n, _ := typ.(*types.Named)
-	return n
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface10.go b/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface10.go
deleted file mode 100644
index 8b163e3..0000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface10.go
+++ /dev/null
@@ -1,22 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build !go1.11
-// +build !go1.11
-
-package gcimporter
-
-import "go/types"
-
-func newInterface(methods []*types.Func, embeddeds []types.Type) *types.Interface {
-	named := make([]*types.Named, len(embeddeds))
-	for i, e := range embeddeds {
-		var ok bool
-		named[i], ok = e.(*types.Named)
-		if !ok {
-			panic("embedding of non-defined interfaces in interfaces is not supported before Go 1.11")
-		}
-	}
-	return types.NewInterface(methods, named)
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface11.go b/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface11.go
deleted file mode 100644
index 49984f4..0000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/newInterface11.go
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build go1.11
-// +build go1.11
-
-package gcimporter
-
-import "go/types"
-
-func newInterface(methods []*types.Func, embeddeds []types.Type) *types.Interface {
-	return types.NewInterfaceType(methods, embeddeds)
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/support_go117.go b/vendor/golang.org/x/tools/go/internal/gcimporter/support_go117.go
deleted file mode 100644
index d892273..0000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/support_go117.go
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright 2021 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build !go1.18
-// +build !go1.18
-
-package gcimporter
-
-import "go/types"
-
-const iexportVersion = iexportVersionGo1_11
-
-func additionalPredeclared() []types.Type {
-	return nil
-}
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/support_go118.go b/vendor/golang.org/x/tools/go/internal/gcimporter/support_go118.go
deleted file mode 100644
index a993843..0000000
--- a/vendor/golang.org/x/tools/go/internal/gcimporter/support_go118.go
+++ /dev/null
@@ -1,23 +0,0 @@
-// Copyright 2021 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build go1.18
-// +build go1.18
-
-package gcimporter
-
-import "go/types"
-
-const iexportVersion = iexportVersionGenerics
-
-// additionalPredeclared returns additional predeclared types in go.1.18.
-func additionalPredeclared() []types.Type {
-	return []types.Type{
-		// comparable
-		types.Universe.Lookup("comparable").Type(),
-
-		// any
-		types.Universe.Lookup("any").Type(),
-	}
-}
diff --git a/vendor/golang.org/x/tools/go/internal/packagesdriver/sizes.go b/vendor/golang.org/x/tools/go/internal/packagesdriver/sizes.go
index 18a002f..333676b 100644
--- a/vendor/golang.org/x/tools/go/internal/packagesdriver/sizes.go
+++ b/vendor/golang.org/x/tools/go/internal/packagesdriver/sizes.go
@@ -8,42 +8,46 @@ package packagesdriver
 import (
 	"context"
 	"fmt"
-	"go/types"
 	"strings"
 
 	"golang.org/x/tools/internal/gocommand"
 )
 
-var debug = false
-
-func GetSizesGolist(ctx context.Context, inv gocommand.Invocation, gocmdRunner *gocommand.Runner) (types.Sizes, error) {
+func GetSizesForArgsGolist(ctx context.Context, inv gocommand.Invocation, gocmdRunner *gocommand.Runner) (string, string, error) {
 	inv.Verb = "list"
 	inv.Args = []string{"-f", "{{context.GOARCH}} {{context.Compiler}}", "--", "unsafe"}
 	stdout, stderr, friendlyErr, rawErr := gocmdRunner.RunRaw(ctx, inv)
 	var goarch, compiler string
 	if rawErr != nil {
-		if rawErrMsg := rawErr.Error(); strings.Contains(rawErrMsg, "cannot find main module") || strings.Contains(rawErrMsg, "go.mod file not found") {
-			// User's running outside of a module. All bets are off. Get GOARCH and guess compiler is gc.
+		rawErrMsg := rawErr.Error()
+		if strings.Contains(rawErrMsg, "cannot find main module") ||
+			strings.Contains(rawErrMsg, "go.mod file not found") {
+			// User's running outside of a module.
+			// All bets are off. Get GOARCH and guess compiler is gc.
 			// TODO(matloob): Is this a problem in practice?
 			inv.Verb = "env"
 			inv.Args = []string{"GOARCH"}
 			envout, enverr := gocmdRunner.Run(ctx, inv)
 			if enverr != nil {
-				return nil, enverr
+				return "", "", enverr
 			}
 			goarch = strings.TrimSpace(envout.String())
 			compiler = "gc"
+		} else if friendlyErr != nil {
+			return "", "", friendlyErr
 		} else {
-			return nil, friendlyErr
+			// This should be unreachable, but be defensive
+			// in case RunRaw's error results are inconsistent.
+			return "", "", rawErr
 		}
 	} else {
 		fields := strings.Fields(stdout.String())
 		if len(fields) < 2 {
-			return nil, fmt.Errorf("could not parse GOARCH and Go compiler in format \"<GOARCH> <compiler>\":\nstdout: <<%s>>\nstderr: <<%s>>",
+			return "", "", fmt.Errorf("could not parse GOARCH and Go compiler in format \"<GOARCH> <compiler>\":\nstdout: <<%s>>\nstderr: <<%s>>",
 				stdout.String(), stderr.String())
 		}
 		goarch = fields[0]
 		compiler = fields[1]
 	}
-	return types.SizesFor(compiler, goarch), nil
+	return compiler, goarch, nil
 }
diff --git a/vendor/golang.org/x/tools/go/packages/doc.go b/vendor/golang.org/x/tools/go/packages/doc.go
index 4bfe28a..a8d7b06 100644
--- a/vendor/golang.org/x/tools/go/packages/doc.go
+++ b/vendor/golang.org/x/tools/go/packages/doc.go
@@ -5,12 +5,20 @@
 /*
 Package packages loads Go packages for inspection and analysis.
 
-The Load function takes as input a list of patterns and return a list of Package
-structs describing individual packages matched by those patterns.
-The LoadMode controls the amount of detail in the loaded packages.
-
-Load passes most patterns directly to the underlying build tool,
-but all patterns with the prefix "query=", where query is a
+The [Load] function takes as input a list of patterns and returns a
+list of [Package] values describing individual packages matched by those
+patterns.
+A [Config] specifies configuration options, the most important of which is
+the [LoadMode], which controls the amount of detail in the loaded packages.
+
+Load passes most patterns directly to the underlying build tool.
+The default build tool is the go command.
+Its supported patterns are described at
+https://pkg.go.dev/cmd/go#hdr-Package_lists_and_patterns.
+Other build systems may be supported by providing a "driver";
+see [The driver protocol].
+
+All patterns with the prefix "query=", where query is a
 non-empty string of letters from [a-z], are reserved and may be
 interpreted as query operators.
 
@@ -35,7 +43,7 @@ The Package struct provides basic information about the package, including
   - Imports, a map from source import strings to the Packages they name;
   - Types, the type information for the package's exported symbols;
   - Syntax, the parsed syntax trees for the package's source code; and
-  - TypeInfo, the result of a complete type-check of the package syntax trees.
+  - TypesInfo, the result of a complete type-check of the package syntax trees.
 
 (See the documentation for type Package for the complete list of fields
 and more detailed descriptions.)
@@ -64,10 +72,31 @@ reported about the loaded packages. See the documentation for type LoadMode
 for details.
 
 Most tools should pass their command-line arguments (after any flags)
-uninterpreted to the loader, so that the loader can interpret them
+uninterpreted to [Load], so that it can interpret them
 according to the conventions of the underlying build system.
+
 See the Example function for typical usage.
 
+# The driver protocol
+
+[Load] may be used to load Go packages even in Go projects that use
+alternative build systems, by installing an appropriate "driver"
+program for the build system and specifying its location in the
+GOPACKAGESDRIVER environment variable.
+For example,
+https://github.com/bazelbuild/rules_go/wiki/Editor-and-tool-integration
+explains how to use the driver for Bazel.
+
+The driver program is responsible for interpreting patterns in its
+preferred notation and reporting information about the packages that
+those patterns identify. Drivers must also support the special "file="
+and "pattern=" patterns described above.
+
+The patterns are provided as positional command-line arguments. A
+JSON-encoded [DriverRequest] message providing additional information
+is written to the driver's standard input. The driver must write a
+JSON-encoded [DriverResponse] message to its standard output. (This
+message differs from the JSON schema produced by 'go list'.)
 */
 package packages // import "golang.org/x/tools/go/packages"
 
diff --git a/vendor/golang.org/x/tools/go/packages/external.go b/vendor/golang.org/x/tools/go/packages/external.go
index 7242a0a..4335c1e 100644
--- a/vendor/golang.org/x/tools/go/packages/external.go
+++ b/vendor/golang.org/x/tools/go/packages/external.go
@@ -2,46 +2,85 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// This file enables an external tool to intercept package requests.
-// If the tool is present then its results are used in preference to
-// the go list command.
-
 package packages
 
+// This file defines the protocol that enables an external "driver"
+// tool to supply package metadata in place of 'go list'.
+
 import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	exec "golang.org/x/sys/execabs"
 	"os"
+	"os/exec"
 	"strings"
 )
 
-// The Driver Protocol
+// DriverRequest defines the schema of a request for package metadata
+// from an external driver program. The JSON-encoded DriverRequest
+// message is provided to the driver program's standard input. The
+// query patterns are provided as command-line arguments.
 //
-// The driver, given the inputs to a call to Load, returns metadata about the packages specified.
-// This allows for different build systems to support go/packages by telling go/packages how the
-// packages' source is organized.
-// The driver is a binary, either specified by the GOPACKAGESDRIVER environment variable or in
-// the path as gopackagesdriver. It's given the inputs to load in its argv. See the package
-// documentation in doc.go for the full description of the patterns that need to be supported.
-// A driver receives as a JSON-serialized driverRequest struct in standard input and will
-// produce a JSON-serialized driverResponse (see definition in packages.go) in its standard output.
-
-// driverRequest is used to provide the portion of Load's Config that is needed by a driver.
-type driverRequest struct {
+// See the package documentation for an overview.
+type DriverRequest struct {
 	Mode LoadMode `json:"mode"`
+
 	// Env specifies the environment the underlying build system should be run in.
 	Env []string `json:"env"`
+
 	// BuildFlags are flags that should be passed to the underlying build system.
 	BuildFlags []string `json:"build_flags"`
+
 	// Tests specifies whether the patterns should also return test packages.
 	Tests bool `json:"tests"`
+
 	// Overlay maps file paths (relative to the driver's working directory) to the byte contents
 	// of overlay files.
 	Overlay map[string][]byte `json:"overlay"`
 }
 
+// DriverResponse defines the schema of a response from an external
+// driver program, providing the results of a query for package
+// metadata. The driver program must write a JSON-encoded
+// DriverResponse message to its standard output.
+//
+// See the package documentation for an overview.
+type DriverResponse struct {
+	// NotHandled is returned if the request can't be handled by the current
+	// driver. If an external driver returns a response with NotHandled, the
+	// rest of the DriverResponse is ignored, and go/packages will fallback
+	// to the next driver. If go/packages is extended in the future to support
+	// lists of multiple drivers, go/packages will fall back to the next driver.
+	NotHandled bool
+
+	// Compiler and Arch are the arguments pass of types.SizesFor
+	// to get a types.Sizes to use when type checking.
+	Compiler string
+	Arch     string
+
+	// Roots is the set of package IDs that make up the root packages.
+	// We have to encode this separately because when we encode a single package
+	// we cannot know if it is one of the roots as that requires knowledge of the
+	// graph it is part of.
+	Roots []string `json:",omitempty"`
+
+	// Packages is the full set of packages in the graph.
+	// The packages are not connected into a graph.
+	// The Imports if populated will be stubs that only have their ID set.
+	// Imports will be connected and then type and syntax information added in a
+	// later pass (see refine).
+	Packages []*Package
+
+	// GoVersion is the minor version number used by the driver
+	// (e.g. the go command on the PATH) when selecting .go files.
+	// Zero means unknown.
+	GoVersion int
+}
+
+// driver is the type for functions that query the build system for the
+// packages named by the patterns.
+type driver func(cfg *Config, patterns ...string) (*DriverResponse, error)
+
 // findExternalDriver returns the file path of a tool that supplies
 // the build system package structure, or "" if not found."
 // If GOPACKAGESDRIVER is set in the environment findExternalTool returns its
@@ -64,8 +103,8 @@ func findExternalDriver(cfg *Config) driver {
 			return nil
 		}
 	}
-	return func(cfg *Config, words ...string) (*driverResponse, error) {
-		req, err := json.Marshal(driverRequest{
+	return func(cfg *Config, words ...string) (*DriverResponse, error) {
+		req, err := json.Marshal(DriverRequest{
 			Mode:       cfg.Mode,
 			Env:        cfg.Env,
 			BuildFlags: cfg.BuildFlags,
@@ -92,7 +131,7 @@ func findExternalDriver(cfg *Config) driver {
 			fmt.Fprintf(os.Stderr, "%s stderr: <<%s>>\n", cmdDebugStr(cmd), stderr)
 		}
 
-		var response driverResponse
+		var response DriverResponse
 		if err := json.Unmarshal(buf.Bytes(), &response); err != nil {
 			return nil, err
 		}
diff --git a/vendor/golang.org/x/tools/go/packages/golist.go b/vendor/golang.org/x/tools/go/packages/golist.go
index 0e1e7f1..22305d9 100644
--- a/vendor/golang.org/x/tools/go/packages/golist.go
+++ b/vendor/golang.org/x/tools/go/packages/golist.go
@@ -9,10 +9,9 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"go/types"
-	"io/ioutil"
 	"log"
 	"os"
+	"os/exec"
 	"path"
 	"path/filepath"
 	"reflect"
@@ -22,11 +21,9 @@ import (
 	"sync"
 	"unicode"
 
-	exec "golang.org/x/sys/execabs"
 	"golang.org/x/tools/go/internal/packagesdriver"
 	"golang.org/x/tools/internal/gocommand"
 	"golang.org/x/tools/internal/packagesinternal"
-	"golang.org/x/xerrors"
 )
 
 // debug controls verbose logging.
@@ -38,29 +35,30 @@ type goTooOldError struct {
 	error
 }
 
-// responseDeduper wraps a driverResponse, deduplicating its contents.
+// responseDeduper wraps a DriverResponse, deduplicating its contents.
 type responseDeduper struct {
 	seenRoots    map[string]bool
 	seenPackages map[string]*Package
-	dr           *driverResponse
+	dr           *DriverResponse
 }
 
 func newDeduper() *responseDeduper {
 	return &responseDeduper{
-		dr:           &driverResponse{},
+		dr:           &DriverResponse{},
 		seenRoots:    map[string]bool{},
 		seenPackages: map[string]*Package{},
 	}
 }
 
-// addAll fills in r with a driverResponse.
-func (r *responseDeduper) addAll(dr *driverResponse) {
+// addAll fills in r with a DriverResponse.
+func (r *responseDeduper) addAll(dr *DriverResponse) {
 	for _, pkg := range dr.Packages {
 		r.addPackage(pkg)
 	}
 	for _, root := range dr.Roots {
 		r.addRoot(root)
 	}
+	r.dr.GoVersion = dr.GoVersion
 }
 
 func (r *responseDeduper) addPackage(p *Package) {
@@ -130,7 +128,7 @@ func (state *golistState) mustGetEnv() map[string]string {
 // goListDriver uses the go list command to interpret the patterns and produce
 // the build system package structure.
 // See driver for more details.
-func goListDriver(cfg *Config, patterns ...string) (*driverResponse, error) {
+func goListDriver(cfg *Config, patterns ...string) (_ *DriverResponse, err error) {
 	// Make sure that any asynchronous go commands are killed when we return.
 	parentCtx := cfg.Context
 	if parentCtx == nil {
@@ -148,16 +146,18 @@ func goListDriver(cfg *Config, patterns ...string) (*driverResponse, error) {
 	}
 
 	// Fill in response.Sizes asynchronously if necessary.
-	var sizeserr error
-	var sizeswg sync.WaitGroup
 	if cfg.Mode&NeedTypesSizes != 0 || cfg.Mode&NeedTypes != 0 {
-		sizeswg.Add(1)
+		errCh := make(chan error)
 		go func() {
-			var sizes types.Sizes
-			sizes, sizeserr = packagesdriver.GetSizesGolist(ctx, state.cfgInvocation(), cfg.gocmdRunner)
-			// types.SizesFor always returns nil or a *types.StdSizes.
-			response.dr.Sizes, _ = sizes.(*types.StdSizes)
-			sizeswg.Done()
+			compiler, arch, err := packagesdriver.GetSizesForArgsGolist(ctx, state.cfgInvocation(), cfg.gocmdRunner)
+			response.dr.Compiler = compiler
+			response.dr.Arch = arch
+			errCh <- err
+		}()
+		defer func() {
+			if sizesErr := <-errCh; sizesErr != nil {
+				err = sizesErr
+			}
 		}()
 	}
 
@@ -210,87 +210,10 @@ extractQueries:
 		}
 	}
 
-	// Only use go/packages' overlay processing if we're using a Go version
-	// below 1.16. Otherwise, go list handles it.
-	if goVersion, err := state.getGoVersion(); err == nil && goVersion < 16 {
-		modifiedPkgs, needPkgs, err := state.processGolistOverlay(response)
-		if err != nil {
-			return nil, err
-		}
-
-		var containsCandidates []string
-		if len(containFiles) > 0 {
-			containsCandidates = append(containsCandidates, modifiedPkgs...)
-			containsCandidates = append(containsCandidates, needPkgs...)
-		}
-		if err := state.addNeededOverlayPackages(response, needPkgs); err != nil {
-			return nil, err
-		}
-		// Check candidate packages for containFiles.
-		if len(containFiles) > 0 {
-			for _, id := range containsCandidates {
-				pkg, ok := response.seenPackages[id]
-				if !ok {
-					response.addPackage(&Package{
-						ID: id,
-						Errors: []Error{{
-							Kind: ListError,
-							Msg:  fmt.Sprintf("package %s expected but not seen", id),
-						}},
-					})
-					continue
-				}
-				for _, f := range containFiles {
-					for _, g := range pkg.GoFiles {
-						if sameFile(f, g) {
-							response.addRoot(id)
-						}
-					}
-				}
-			}
-		}
-		// Add root for any package that matches a pattern. This applies only to
-		// packages that are modified by overlays, since they are not added as
-		// roots automatically.
-		for _, pattern := range restPatterns {
-			match := matchPattern(pattern)
-			for _, pkgID := range modifiedPkgs {
-				pkg, ok := response.seenPackages[pkgID]
-				if !ok {
-					continue
-				}
-				if match(pkg.PkgPath) {
-					response.addRoot(pkg.ID)
-				}
-			}
-		}
-	}
-
-	sizeswg.Wait()
-	if sizeserr != nil {
-		return nil, sizeserr
-	}
+	// (We may yet return an error due to defer.)
 	return response.dr, nil
 }
 
-func (state *golistState) addNeededOverlayPackages(response *responseDeduper, pkgs []string) error {
-	if len(pkgs) == 0 {
-		return nil
-	}
-	dr, err := state.createDriverResponse(pkgs...)
-	if err != nil {
-		return err
-	}
-	for _, pkg := range dr.Packages {
-		response.addPackage(pkg)
-	}
-	_, needPkgs, err := state.processGolistOverlay(response)
-	if err != nil {
-		return err
-	}
-	return state.addNeededOverlayPackages(response, needPkgs)
-}
-
 func (state *golistState) runContainsQueries(response *responseDeduper, queries []string) error {
 	for _, query := range queries {
 		// TODO(matloob): Do only one query per directory.
@@ -303,11 +226,12 @@ func (state *golistState) runContainsQueries(response *responseDeduper, queries
 		}
 		dirResponse, err := state.createDriverResponse(pattern)
 
-		// If there was an error loading the package, or the package is returned
-		// with errors, try to load the file as an ad-hoc package.
+		// If there was an error loading the package, or no packages are returned,
+		// or the package is returned with errors, try to load the file as an
+		// ad-hoc package.
 		// Usually the error will appear in a returned package, but may not if we're
 		// in module mode and the ad-hoc is located outside a module.
-		if err != nil || len(dirResponse.Packages) == 1 && len(dirResponse.Packages[0].GoFiles) == 0 &&
+		if err != nil || len(dirResponse.Packages) == 0 || len(dirResponse.Packages) == 1 && len(dirResponse.Packages[0].GoFiles) == 0 &&
 			len(dirResponse.Packages[0].Errors) == 1 {
 			var queryErr error
 			if dirResponse, queryErr = state.adhocPackage(pattern, query); queryErr != nil {
@@ -341,7 +265,7 @@ func (state *golistState) runContainsQueries(response *responseDeduper, queries
 
 // adhocPackage attempts to load or construct an ad-hoc package for a given
 // query, if the original call to the driver produced inadequate results.
-func (state *golistState) adhocPackage(pattern, query string) (*driverResponse, error) {
+func (state *golistState) adhocPackage(pattern, query string) (*DriverResponse, error) {
 	response, err := state.createDriverResponse(query)
 	if err != nil {
 		return nil, err
@@ -393,6 +317,8 @@ type jsonPackage struct {
 	CompiledGoFiles   []string
 	IgnoredGoFiles    []string
 	IgnoredOtherFiles []string
+	EmbedPatterns     []string
+	EmbedFiles        []string
 	CFiles            []string
 	CgoFiles          []string
 	CXXFiles          []string
@@ -430,7 +356,7 @@ func otherFiles(p *jsonPackage) [][]string {
 
 // createDriverResponse uses the "go list" command to expand the pattern
 // words and return a response for the specified packages.
-func (state *golistState) createDriverResponse(words ...string) (*driverResponse, error) {
+func (state *golistState) createDriverResponse(words ...string) (*DriverResponse, error) {
 	// go list uses the following identifiers in ImportPath and Imports:
 	//
 	// 	"p"			-- importable package or main (command)
@@ -444,15 +370,22 @@ func (state *golistState) createDriverResponse(words ...string) (*driverResponse
 
 	// Run "go list" for complete
 	// information on the specified packages.
-	buf, err := state.invokeGo("list", golistargs(state.cfg, words)...)
+	goVersion, err := state.getGoVersion()
 	if err != nil {
 		return nil, err
 	}
+	buf, err := state.invokeGo("list", golistargs(state.cfg, words, goVersion)...)
+	if err != nil {
+		return nil, err
+	}
+
 	seen := make(map[string]*jsonPackage)
 	pkgs := make(map[string]*Package)
 	additionalErrors := make(map[string][]Error)
 	// Decode the JSON and convert it to Package form.
-	var response driverResponse
+	response := &DriverResponse{
+		GoVersion: goVersion,
+	}
 	for dec := json.NewDecoder(buf); dec.More(); {
 		p := new(jsonPackage)
 		if err := dec.Decode(p); err != nil {
@@ -565,6 +498,8 @@ func (state *golistState) createDriverResponse(words ...string) (*driverResponse
 			GoFiles:         absJoin(p.Dir, p.GoFiles, p.CgoFiles),
 			CompiledGoFiles: absJoin(p.Dir, p.CompiledGoFiles),
 			OtherFiles:      absJoin(p.Dir, otherFiles(p)...),
+			EmbedFiles:      absJoin(p.Dir, p.EmbedFiles),
+			EmbedPatterns:   absJoin(p.Dir, p.EmbedPatterns),
 			IgnoredFiles:    absJoin(p.Dir, p.IgnoredGoFiles, p.IgnoredOtherFiles),
 			forTest:         p.ForTest,
 			depsErrors:      p.DepsErrors,
@@ -592,17 +527,12 @@ func (state *golistState) createDriverResponse(words ...string) (*driverResponse
 
 		// Work around https://golang.org/issue/28749:
 		// cmd/go puts assembly, C, and C++ files in CompiledGoFiles.
-		// Filter out any elements of CompiledGoFiles that are also in OtherFiles.
-		// We have to keep this workaround in place until go1.12 is a distant memory.
-		if len(pkg.OtherFiles) > 0 {
-			other := make(map[string]bool, len(pkg.OtherFiles))
-			for _, f := range pkg.OtherFiles {
-				other[f] = true
-			}
-
+		// Remove files from CompiledGoFiles that are non-go files
+		// (or are not files that look like they are from the cache).
+		if len(pkg.CompiledGoFiles) > 0 {
 			out := pkg.CompiledGoFiles[:0]
 			for _, f := range pkg.CompiledGoFiles {
-				if other[f] {
+				if ext := filepath.Ext(f); ext != ".go" && ext != "" { // ext == "" means the file is from the cache, so probably cgo-processed file
 					continue
 				}
 				out = append(out, f)
@@ -618,7 +548,12 @@ func (state *golistState) createDriverResponse(words ...string) (*driverResponse
 		}
 
 		if pkg.PkgPath == "unsafe" {
-			pkg.GoFiles = nil // ignore fake unsafe.go file
+			pkg.CompiledGoFiles = nil // ignore fake unsafe.go file (#59929)
+		} else if len(pkg.CompiledGoFiles) == 0 {
+			// Work around for pre-go.1.11 versions of go list.
+			// TODO(matloob): they should be handled by the fallback.
+			// Can we delete this?
+			pkg.CompiledGoFiles = pkg.GoFiles
 		}
 
 		// Assume go list emits only absolute paths for Dir.
@@ -656,16 +591,12 @@ func (state *golistState) createDriverResponse(words ...string) (*driverResponse
 			response.Roots = append(response.Roots, pkg.ID)
 		}
 
-		// Work around for pre-go.1.11 versions of go list.
-		// TODO(matloob): they should be handled by the fallback.
-		// Can we delete this?
-		if len(pkg.CompiledGoFiles) == 0 {
-			pkg.CompiledGoFiles = pkg.GoFiles
-		}
-
 		// Temporary work-around for golang/go#39986. Parse filenames out of
 		// error messages. This happens if there are unrecoverable syntax
 		// errors in the source, so we can't match on a specific error message.
+		//
+		// TODO(rfindley): remove this heuristic, in favor of considering
+		// InvalidGoFiles from the list driver.
 		if err := p.Error; err != nil && state.shouldAddFilenameFromError(p) {
 			addFilenameFromPos := func(pos string) bool {
 				split := strings.Split(pos, ":")
@@ -722,7 +653,7 @@ func (state *golistState) createDriverResponse(words ...string) (*driverResponse
 	}
 	sort.Slice(response.Packages, func(i, j int) bool { return response.Packages[i].ID < response.Packages[j].ID })
 
-	return &response, nil
+	return response, nil
 }
 
 func (state *golistState) shouldAddFilenameFromError(p *jsonPackage) bool {
@@ -748,6 +679,7 @@ func (state *golistState) shouldAddFilenameFromError(p *jsonPackage) bool {
 	return len(p.Error.ImportStack) == 0 || p.Error.ImportStack[len(p.Error.ImportStack)-1] == p.ImportPath
 }
 
+// getGoVersion returns the effective minor version of the go command.
 func (state *golistState) getGoVersion() (int, error) {
 	state.goVersionOnce.Do(func() {
 		state.goVersion, state.goVersionError = gocommand.GoVersion(state.ctx, state.cfgInvocation(), state.cfg.gocmdRunner)
@@ -805,18 +737,93 @@ func absJoin(dir string, fileses ...[]string) (res []string) {
 	return res
 }
 
-func golistargs(cfg *Config, words []string) []string {
+func jsonFlag(cfg *Config, goVersion int) string {
+	if goVersion < 19 {
+		return "-json"
+	}
+	var fields []string
+	added := make(map[string]bool)
+	addFields := func(fs ...string) {
+		for _, f := range fs {
+			if !added[f] {
+				added[f] = true
+				fields = append(fields, f)
+			}
+		}
+	}
+	addFields("Name", "ImportPath", "Error") // These fields are always needed
+	if cfg.Mode&NeedFiles != 0 || cfg.Mode&NeedTypes != 0 {
+		addFields("Dir", "GoFiles", "IgnoredGoFiles", "IgnoredOtherFiles", "CFiles",
+			"CgoFiles", "CXXFiles", "MFiles", "HFiles", "FFiles", "SFiles",
+			"SwigFiles", "SwigCXXFiles", "SysoFiles")
+		if cfg.Tests {
+			addFields("TestGoFiles", "XTestGoFiles")
+		}
+	}
+	if cfg.Mode&NeedTypes != 0 {
+		// CompiledGoFiles seems to be required for the test case TestCgoNoSyntax,
+		// even when -compiled isn't passed in.
+		// TODO(#52435): Should we make the test ask for -compiled, or automatically
+		// request CompiledGoFiles in certain circumstances?
+		addFields("Dir", "CompiledGoFiles")
+	}
+	if cfg.Mode&NeedCompiledGoFiles != 0 {
+		addFields("Dir", "CompiledGoFiles", "Export")
+	}
+	if cfg.Mode&NeedImports != 0 {
+		// When imports are requested, DepOnly is used to distinguish between packages
+		// explicitly requested and transitive imports of those packages.
+		addFields("DepOnly", "Imports", "ImportMap")
+		if cfg.Tests {
+			addFields("TestImports", "XTestImports")
+		}
+	}
+	if cfg.Mode&NeedDeps != 0 {
+		addFields("DepOnly")
+	}
+	if usesExportData(cfg) {
+		// Request Dir in the unlikely case Export is not absolute.
+		addFields("Dir", "Export")
+	}
+	if cfg.Mode&needInternalForTest != 0 {
+		addFields("ForTest")
+	}
+	if cfg.Mode&needInternalDepsErrors != 0 {
+		addFields("DepsErrors")
+	}
+	if cfg.Mode&NeedModule != 0 {
+		addFields("Module")
+	}
+	if cfg.Mode&NeedEmbedFiles != 0 {
+		addFields("EmbedFiles")
+	}
+	if cfg.Mode&NeedEmbedPatterns != 0 {
+		addFields("EmbedPatterns")
+	}
+	return "-json=" + strings.Join(fields, ",")
+}
+
+func golistargs(cfg *Config, words []string, goVersion int) []string {
 	const findFlags = NeedImports | NeedTypes | NeedSyntax | NeedTypesInfo
 	fullargs := []string{
-		"-e", "-json",
+		"-e", jsonFlag(cfg, goVersion),
 		fmt.Sprintf("-compiled=%t", cfg.Mode&(NeedCompiledGoFiles|NeedSyntax|NeedTypes|NeedTypesInfo|NeedTypesSizes) != 0),
 		fmt.Sprintf("-test=%t", cfg.Tests),
 		fmt.Sprintf("-export=%t", usesExportData(cfg)),
 		fmt.Sprintf("-deps=%t", cfg.Mode&NeedImports != 0),
 		// go list doesn't let you pass -test and -find together,
 		// probably because you'd just get the TestMain.
-		fmt.Sprintf("-find=%t", !cfg.Tests && cfg.Mode&findFlags == 0),
+		fmt.Sprintf("-find=%t", !cfg.Tests && cfg.Mode&findFlags == 0 && !usesExportData(cfg)),
+	}
+
+	// golang/go#60456: with go1.21 and later, go list serves pgo variants, which
+	// can be costly to compute and may result in redundant processing for the
+	// caller. Disable these variants. If someone wants to add e.g. a NeedPGO
+	// mode flag, that should be a separate proposal.
+	if goVersion >= 21 {
+		fullargs = append(fullargs, "-pgo=off")
 	}
+
 	fullargs = append(fullargs, cfg.BuildFlags...)
 	fullargs = append(fullargs, "--")
 	fullargs = append(fullargs, words...)
@@ -879,7 +886,7 @@ func (state *golistState) invokeGo(verb string, args ...string) (*bytes.Buffer,
 		if !ok {
 			// Catastrophic error:
 			// - context cancellation
-			return nil, xerrors.Errorf("couldn't run 'go': %w", err)
+			return nil, fmt.Errorf("couldn't run 'go': %w", err)
 		}
 
 		// Old go version?
@@ -1026,7 +1033,7 @@ func (state *golistState) writeOverlays() (filename string, cleanup func(), err
 	if len(state.cfg.Overlay) == 0 {
 		return "", func() {}, nil
 	}
-	dir, err := ioutil.TempDir("", "gopackages-*")
+	dir, err := os.MkdirTemp("", "gopackages-*")
 	if err != nil {
 		return "", nil, err
 	}
@@ -1045,7 +1052,7 @@ func (state *golistState) writeOverlays() (filename string, cleanup func(), err
 		// Create a unique filename for the overlaid files, to avoid
 		// creating nested directories.
 		noSeparator := strings.Join(strings.Split(filepath.ToSlash(k), "/"), "")
-		f, err := ioutil.TempFile(dir, fmt.Sprintf("*-%s", noSeparator))
+		f, err := os.CreateTemp(dir, fmt.Sprintf("*-%s", noSeparator))
 		if err != nil {
 			return "", func() {}, err
 		}
@@ -1063,7 +1070,7 @@ func (state *golistState) writeOverlays() (filename string, cleanup func(), err
 	}
 	// Write out the overlay file that contains the filepath mappings.
 	filename = filepath.Join(dir, "overlay.json")
-	if err := ioutil.WriteFile(filename, b, 0665); err != nil {
+	if err := os.WriteFile(filename, b, 0665); err != nil {
 		return "", func() {}, err
 	}
 	return filename, cleanup, nil
diff --git a/vendor/golang.org/x/tools/go/packages/golist_overlay.go b/vendor/golang.org/x/tools/go/packages/golist_overlay.go
index 9576b47..d823c47 100644
--- a/vendor/golang.org/x/tools/go/packages/golist_overlay.go
+++ b/vendor/golang.org/x/tools/go/packages/golist_overlay.go
@@ -6,314 +6,11 @@ package packages
 
 import (
 	"encoding/json"
-	"fmt"
-	"go/parser"
-	"go/token"
-	"os"
 	"path/filepath"
-	"regexp"
-	"sort"
-	"strconv"
-	"strings"
 
 	"golang.org/x/tools/internal/gocommand"
 )
 
-// processGolistOverlay provides rudimentary support for adding
-// files that don't exist on disk to an overlay. The results can be
-// sometimes incorrect.
-// TODO(matloob): Handle unsupported cases, including the following:
-// - determining the correct package to add given a new import path
-func (state *golistState) processGolistOverlay(response *responseDeduper) (modifiedPkgs, needPkgs []string, err error) {
-	havePkgs := make(map[string]string) // importPath -> non-test package ID
-	needPkgsSet := make(map[string]bool)
-	modifiedPkgsSet := make(map[string]bool)
-
-	pkgOfDir := make(map[string][]*Package)
-	for _, pkg := range response.dr.Packages {
-		// This is an approximation of import path to id. This can be
-		// wrong for tests, vendored packages, and a number of other cases.
-		havePkgs[pkg.PkgPath] = pkg.ID
-		dir, err := commonDir(pkg.GoFiles)
-		if err != nil {
-			return nil, nil, err
-		}
-		if dir != "" {
-			pkgOfDir[dir] = append(pkgOfDir[dir], pkg)
-		}
-	}
-
-	// If no new imports are added, it is safe to avoid loading any needPkgs.
-	// Otherwise, it's hard to tell which package is actually being loaded
-	// (due to vendoring) and whether any modified package will show up
-	// in the transitive set of dependencies (because new imports are added,
-	// potentially modifying the transitive set of dependencies).
-	var overlayAddsImports bool
-
-	// If both a package and its test package are created by the overlay, we
-	// need the real package first. Process all non-test files before test
-	// files, and make the whole process deterministic while we're at it.
-	var overlayFiles []string
-	for opath := range state.cfg.Overlay {
-		overlayFiles = append(overlayFiles, opath)
-	}
-	sort.Slice(overlayFiles, func(i, j int) bool {
-		iTest := strings.HasSuffix(overlayFiles[i], "_test.go")
-		jTest := strings.HasSuffix(overlayFiles[j], "_test.go")
-		if iTest != jTest {
-			return !iTest // non-tests are before tests.
-		}
-		return overlayFiles[i] < overlayFiles[j]
-	})
-	for _, opath := range overlayFiles {
-		contents := state.cfg.Overlay[opath]
-		base := filepath.Base(opath)
-		dir := filepath.Dir(opath)
-		var pkg *Package           // if opath belongs to both a package and its test variant, this will be the test variant
-		var testVariantOf *Package // if opath is a test file, this is the package it is testing
-		var fileExists bool
-		isTestFile := strings.HasSuffix(opath, "_test.go")
-		pkgName, ok := extractPackageName(opath, contents)
-		if !ok {
-			// Don't bother adding a file that doesn't even have a parsable package statement
-			// to the overlay.
-			continue
-		}
-		// If all the overlay files belong to a different package, change the
-		// package name to that package.
-		maybeFixPackageName(pkgName, isTestFile, pkgOfDir[dir])
-	nextPackage:
-		for _, p := range response.dr.Packages {
-			if pkgName != p.Name && p.ID != "command-line-arguments" {
-				continue
-			}
-			for _, f := range p.GoFiles {
-				if !sameFile(filepath.Dir(f), dir) {
-					continue
-				}
-				// Make sure to capture information on the package's test variant, if needed.
-				if isTestFile && !hasTestFiles(p) {
-					// TODO(matloob): Are there packages other than the 'production' variant
-					// of a package that this can match? This shouldn't match the test main package
-					// because the file is generated in another directory.
-					testVariantOf = p
-					continue nextPackage
-				} else if !isTestFile && hasTestFiles(p) {
-					// We're examining a test variant, but the overlaid file is
-					// a non-test file. Because the overlay implementation
-					// (currently) only adds a file to one package, skip this
-					// package, so that we can add the file to the production
-					// variant of the package. (https://golang.org/issue/36857
-					// tracks handling overlays on both the production and test
-					// variant of a package).
-					continue nextPackage
-				}
-				if pkg != nil && p != pkg && pkg.PkgPath == p.PkgPath {
-					// We have already seen the production version of the
-					// for which p is a test variant.
-					if hasTestFiles(p) {
-						testVariantOf = pkg
-					}
-				}
-				pkg = p
-				if filepath.Base(f) == base {
-					fileExists = true
-				}
-			}
-		}
-		// The overlay could have included an entirely new package or an
-		// ad-hoc package. An ad-hoc package is one that we have manually
-		// constructed from inadequate `go list` results for a file= query.
-		// It will have the ID command-line-arguments.
-		if pkg == nil || pkg.ID == "command-line-arguments" {
-			// Try to find the module or gopath dir the file is contained in.
-			// Then for modules, add the module opath to the beginning.
-			pkgPath, ok, err := state.getPkgPath(dir)
-			if err != nil {
-				return nil, nil, err
-			}
-			if !ok {
-				break
-			}
-			var forTest string // only set for x tests
-			isXTest := strings.HasSuffix(pkgName, "_test")
-			if isXTest {
-				forTest = pkgPath
-				pkgPath += "_test"
-			}
-			id := pkgPath
-			if isTestFile {
-				if isXTest {
-					id = fmt.Sprintf("%s [%s.test]", pkgPath, forTest)
-				} else {
-					id = fmt.Sprintf("%s [%s.test]", pkgPath, pkgPath)
-				}
-			}
-			if pkg != nil {
-				// TODO(rstambler): We should change the package's path and ID
-				// here. The only issue is that this messes with the roots.
-			} else {
-				// Try to reclaim a package with the same ID, if it exists in the response.
-				for _, p := range response.dr.Packages {
-					if reclaimPackage(p, id, opath, contents) {
-						pkg = p
-						break
-					}
-				}
-				// Otherwise, create a new package.
-				if pkg == nil {
-					pkg = &Package{
-						PkgPath: pkgPath,
-						ID:      id,
-						Name:    pkgName,
-						Imports: make(map[string]*Package),
-					}
-					response.addPackage(pkg)
-					havePkgs[pkg.PkgPath] = id
-					// Add the production package's sources for a test variant.
-					if isTestFile && !isXTest && testVariantOf != nil {
-						pkg.GoFiles = append(pkg.GoFiles, testVariantOf.GoFiles...)
-						pkg.CompiledGoFiles = append(pkg.CompiledGoFiles, testVariantOf.CompiledGoFiles...)
-						// Add the package under test and its imports to the test variant.
-						pkg.forTest = testVariantOf.PkgPath
-						for k, v := range testVariantOf.Imports {
-							pkg.Imports[k] = &Package{ID: v.ID}
-						}
-					}
-					if isXTest {
-						pkg.forTest = forTest
-					}
-				}
-			}
-		}
-		if !fileExists {
-			pkg.GoFiles = append(pkg.GoFiles, opath)
-			// TODO(matloob): Adding the file to CompiledGoFiles can exhibit the wrong behavior
-			// if the file will be ignored due to its build tags.
-			pkg.CompiledGoFiles = append(pkg.CompiledGoFiles, opath)
-			modifiedPkgsSet[pkg.ID] = true
-		}
-		imports, err := extractImports(opath, contents)
-		if err != nil {
-			// Let the parser or type checker report errors later.
-			continue
-		}
-		for _, imp := range imports {
-			// TODO(rstambler): If the package is an x test and the import has
-			// a test variant, make sure to replace it.
-			if _, found := pkg.Imports[imp]; found {
-				continue
-			}
-			overlayAddsImports = true
-			id, ok := havePkgs[imp]
-			if !ok {
-				var err error
-				id, err = state.resolveImport(dir, imp)
-				if err != nil {
-					return nil, nil, err
-				}
-			}
-			pkg.Imports[imp] = &Package{ID: id}
-			// Add dependencies to the non-test variant version of this package as well.
-			if testVariantOf != nil {
-				testVariantOf.Imports[imp] = &Package{ID: id}
-			}
-		}
-	}
-
-	// toPkgPath guesses the package path given the id.
-	toPkgPath := func(sourceDir, id string) (string, error) {
-		if i := strings.IndexByte(id, ' '); i >= 0 {
-			return state.resolveImport(sourceDir, id[:i])
-		}
-		return state.resolveImport(sourceDir, id)
-	}
-
-	// Now that new packages have been created, do another pass to determine
-	// the new set of missing packages.
-	for _, pkg := range response.dr.Packages {
-		for _, imp := range pkg.Imports {
-			if len(pkg.GoFiles) == 0 {
-				return nil, nil, fmt.Errorf("cannot resolve imports for package %q with no Go files", pkg.PkgPath)
-			}
-			pkgPath, err := toPkgPath(filepath.Dir(pkg.GoFiles[0]), imp.ID)
-			if err != nil {
-				return nil, nil, err
-			}
-			if _, ok := havePkgs[pkgPath]; !ok {
-				needPkgsSet[pkgPath] = true
-			}
-		}
-	}
-
-	if overlayAddsImports {
-		needPkgs = make([]string, 0, len(needPkgsSet))
-		for pkg := range needPkgsSet {
-			needPkgs = append(needPkgs, pkg)
-		}
-	}
-	modifiedPkgs = make([]string, 0, len(modifiedPkgsSet))
-	for pkg := range modifiedPkgsSet {
-		modifiedPkgs = append(modifiedPkgs, pkg)
-	}
-	return modifiedPkgs, needPkgs, err
-}
-
-// resolveImport finds the ID of a package given its import path.
-// In particular, it will find the right vendored copy when in GOPATH mode.
-func (state *golistState) resolveImport(sourceDir, importPath string) (string, error) {
-	env, err := state.getEnv()
-	if err != nil {
-		return "", err
-	}
-	if env["GOMOD"] != "" {
-		return importPath, nil
-	}
-
-	searchDir := sourceDir
-	for {
-		vendorDir := filepath.Join(searchDir, "vendor")
-		exists, ok := state.vendorDirs[vendorDir]
-		if !ok {
-			info, err := os.Stat(vendorDir)
-			exists = err == nil && info.IsDir()
-			state.vendorDirs[vendorDir] = exists
-		}
-
-		if exists {
-			vendoredPath := filepath.Join(vendorDir, importPath)
-			if info, err := os.Stat(vendoredPath); err == nil && info.IsDir() {
-				// We should probably check for .go files here, but shame on anyone who fools us.
-				path, ok, err := state.getPkgPath(vendoredPath)
-				if err != nil {
-					return "", err
-				}
-				if ok {
-					return path, nil
-				}
-			}
-		}
-
-		// We know we've hit the top of the filesystem when we Dir / and get /,
-		// or C:\ and get C:\, etc.
-		next := filepath.Dir(searchDir)
-		if next == searchDir {
-			break
-		}
-		searchDir = next
-	}
-	return importPath, nil
-}
-
-func hasTestFiles(p *Package) bool {
-	for _, f := range p.GoFiles {
-		if strings.HasSuffix(f, "_test.go") {
-			return true
-		}
-	}
-	return false
-}
-
 // determineRootDirs returns a mapping from absolute directories that could
 // contain code to their corresponding import path prefixes.
 func (state *golistState) determineRootDirs() (map[string]string, error) {
@@ -384,192 +81,3 @@ func (state *golistState) determineRootDirsGOPATH() (map[string]string, error) {
 	}
 	return m, nil
 }
-
-func extractImports(filename string, contents []byte) ([]string, error) {
-	f, err := parser.ParseFile(token.NewFileSet(), filename, contents, parser.ImportsOnly) // TODO(matloob): reuse fileset?
-	if err != nil {
-		return nil, err
-	}
-	var res []string
-	for _, imp := range f.Imports {
-		quotedPath := imp.Path.Value
-		path, err := strconv.Unquote(quotedPath)
-		if err != nil {
-			return nil, err
-		}
-		res = append(res, path)
-	}
-	return res, nil
-}
-
-// reclaimPackage attempts to reuse a package that failed to load in an overlay.
-//
-// If the package has errors and has no Name, GoFiles, or Imports,
-// then it's possible that it doesn't yet exist on disk.
-func reclaimPackage(pkg *Package, id string, filename string, contents []byte) bool {
-	// TODO(rstambler): Check the message of the actual error?
-	// It differs between $GOPATH and module mode.
-	if pkg.ID != id {
-		return false
-	}
-	if len(pkg.Errors) != 1 {
-		return false
-	}
-	if pkg.Name != "" || pkg.ExportFile != "" {
-		return false
-	}
-	if len(pkg.GoFiles) > 0 || len(pkg.CompiledGoFiles) > 0 || len(pkg.OtherFiles) > 0 {
-		return false
-	}
-	if len(pkg.Imports) > 0 {
-		return false
-	}
-	pkgName, ok := extractPackageName(filename, contents)
-	if !ok {
-		return false
-	}
-	pkg.Name = pkgName
-	pkg.Errors = nil
-	return true
-}
-
-func extractPackageName(filename string, contents []byte) (string, bool) {
-	// TODO(rstambler): Check the message of the actual error?
-	// It differs between $GOPATH and module mode.
-	f, err := parser.ParseFile(token.NewFileSet(), filename, contents, parser.PackageClauseOnly) // TODO(matloob): reuse fileset?
-	if err != nil {
-		return "", false
-	}
-	return f.Name.Name, true
-}
-
-// commonDir returns the directory that all files are in, "" if files is empty,
-// or an error if they aren't in the same directory.
-func commonDir(files []string) (string, error) {
-	seen := make(map[string]bool)
-	for _, f := range files {
-		seen[filepath.Dir(f)] = true
-	}
-	if len(seen) > 1 {
-		return "", fmt.Errorf("files (%v) are in more than one directory: %v", files, seen)
-	}
-	for k := range seen {
-		// seen has only one element; return it.
-		return k, nil
-	}
-	return "", nil // no files
-}
-
-// It is possible that the files in the disk directory dir have a different package
-// name from newName, which is deduced from the overlays. If they all have a different
-// package name, and they all have the same package name, then that name becomes
-// the package name.
-// It returns true if it changes the package name, false otherwise.
-func maybeFixPackageName(newName string, isTestFile bool, pkgsOfDir []*Package) {
-	names := make(map[string]int)
-	for _, p := range pkgsOfDir {
-		names[p.Name]++
-	}
-	if len(names) != 1 {
-		// some files are in different packages
-		return
-	}
-	var oldName string
-	for k := range names {
-		oldName = k
-	}
-	if newName == oldName {
-		return
-	}
-	// We might have a case where all of the package names in the directory are
-	// the same, but the overlay file is for an x test, which belongs to its
-	// own package. If the x test does not yet exist on disk, we may not yet
-	// have its package name on disk, but we should not rename the packages.
-	//
-	// We use a heuristic to determine if this file belongs to an x test:
-	// The test file should have a package name whose package name has a _test
-	// suffix or looks like "newName_test".
-	maybeXTest := strings.HasPrefix(oldName+"_test", newName) || strings.HasSuffix(newName, "_test")
-	if isTestFile && maybeXTest {
-		return
-	}
-	for _, p := range pkgsOfDir {
-		p.Name = newName
-	}
-}
-
-// This function is copy-pasted from
-// https://github.com/golang/go/blob/9706f510a5e2754595d716bd64be8375997311fb/src/cmd/go/internal/search/search.go#L360.
-// It should be deleted when we remove support for overlays from go/packages.
-//
-// NOTE: This does not handle any ./... or ./ style queries, as this function
-// doesn't know the working directory.
-//
-// matchPattern(pattern)(name) reports whether
-// name matches pattern. Pattern is a limited glob
-// pattern in which '...' means 'any string' and there
-// is no other special syntax.
-// Unfortunately, there are two special cases. Quoting "go help packages":
-//
-// First, /... at the end of the pattern can match an empty string,
-// so that net/... matches both net and packages in its subdirectories, like net/http.
-// Second, any slash-separated pattern element containing a wildcard never
-// participates in a match of the "vendor" element in the path of a vendored
-// package, so that ./... does not match packages in subdirectories of
-// ./vendor or ./mycode/vendor, but ./vendor/... and ./mycode/vendor/... do.
-// Note, however, that a directory named vendor that itself contains code
-// is not a vendored package: cmd/vendor would be a command named vendor,
-// and the pattern cmd/... matches it.
-func matchPattern(pattern string) func(name string) bool {
-	// Convert pattern to regular expression.
-	// The strategy for the trailing /... is to nest it in an explicit ? expression.
-	// The strategy for the vendor exclusion is to change the unmatchable
-	// vendor strings to a disallowed code point (vendorChar) and to use
-	// "(anything but that codepoint)*" as the implementation of the ... wildcard.
-	// This is a bit complicated but the obvious alternative,
-	// namely a hand-written search like in most shell glob matchers,
-	// is too easy to make accidentally exponential.
-	// Using package regexp guarantees linear-time matching.
-
-	const vendorChar = "\x00"
-
-	if strings.Contains(pattern, vendorChar) {
-		return func(name string) bool { return false }
-	}
-
-	re := regexp.QuoteMeta(pattern)
-	re = replaceVendor(re, vendorChar)
-	switch {
-	case strings.HasSuffix(re, `/`+vendorChar+`/\.\.\.`):
-		re = strings.TrimSuffix(re, `/`+vendorChar+`/\.\.\.`) + `(/vendor|/` + vendorChar + `/\.\.\.)`
-	case re == vendorChar+`/\.\.\.`:
-		re = `(/vendor|/` + vendorChar + `/\.\.\.)`
-	case strings.HasSuffix(re, `/\.\.\.`):
-		re = strings.TrimSuffix(re, `/\.\.\.`) + `(/\.\.\.)?`
-	}
-	re = strings.ReplaceAll(re, `\.\.\.`, `[^`+vendorChar+`]*`)
-
-	reg := regexp.MustCompile(`^` + re + `$`)
-
-	return func(name string) bool {
-		if strings.Contains(name, vendorChar) {
-			return false
-		}
-		return reg.MatchString(replaceVendor(name, vendorChar))
-	}
-}
-
-// replaceVendor returns the result of replacing
-// non-trailing vendor path elements in x with repl.
-func replaceVendor(x, repl string) string {
-	if !strings.Contains(x, "vendor") {
-		return x
-	}
-	elem := strings.Split(x, "/")
-	for i := 0; i < len(elem)-1; i++ {
-		if elem[i] == "vendor" {
-			elem[i] = repl
-		}
-	}
-	return strings.Join(elem, "/")
-}
diff --git a/vendor/golang.org/x/tools/go/packages/loadmode_string.go b/vendor/golang.org/x/tools/go/packages/loadmode_string.go
index 7ea37e7..5c080d2 100644
--- a/vendor/golang.org/x/tools/go/packages/loadmode_string.go
+++ b/vendor/golang.org/x/tools/go/packages/loadmode_string.go
@@ -15,7 +15,7 @@ var allModes = []LoadMode{
 	NeedCompiledGoFiles,
 	NeedImports,
 	NeedDeps,
-	NeedExportsFile,
+	NeedExportFile,
 	NeedTypes,
 	NeedSyntax,
 	NeedTypesInfo,
@@ -28,7 +28,7 @@ var modeStrings = []string{
 	"NeedCompiledGoFiles",
 	"NeedImports",
 	"NeedDeps",
-	"NeedExportsFile",
+	"NeedExportFile",
 	"NeedTypes",
 	"NeedSyntax",
 	"NeedTypesInfo",
diff --git a/vendor/golang.org/x/tools/go/packages/packages.go b/vendor/golang.org/x/tools/go/packages/packages.go
index d545b13..f33b0af 100644
--- a/vendor/golang.org/x/tools/go/packages/packages.go
+++ b/vendor/golang.org/x/tools/go/packages/packages.go
@@ -15,10 +15,11 @@ import (
 	"go/scanner"
 	"go/token"
 	"go/types"
-	"io/ioutil"
+	"io"
 	"log"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"sync"
 	"time"
@@ -26,8 +27,8 @@ import (
 	"golang.org/x/tools/go/gcexportdata"
 	"golang.org/x/tools/internal/gocommand"
 	"golang.org/x/tools/internal/packagesinternal"
-	"golang.org/x/tools/internal/typeparams"
 	"golang.org/x/tools/internal/typesinternal"
+	"golang.org/x/tools/internal/versions"
 )
 
 // A LoadMode controls the amount of detail to return when loading.
@@ -39,9 +40,6 @@ import (
 // Load may return more information than requested.
 type LoadMode int
 
-// TODO(matloob): When a V2 of go/packages is released, rename NeedExportsFile to
-// NeedExportFile to make it consistent with the Package field it's adding.
-
 const (
 	// NeedName adds Name and PkgPath.
 	NeedName LoadMode = 1 << iota
@@ -59,8 +57,8 @@ const (
 	// NeedDeps adds the fields requested by the LoadMode in the packages in Imports.
 	NeedDeps
 
-	// NeedExportsFile adds ExportFile.
-	NeedExportsFile
+	// NeedExportFile adds ExportFile.
+	NeedExportFile
 
 	// NeedTypes adds Types, Fset, and IllTyped.
 	NeedTypes
@@ -74,12 +72,25 @@ const (
 	// NeedTypesSizes adds TypesSizes.
 	NeedTypesSizes
 
+	// needInternalDepsErrors adds the internal deps errors field for use by gopls.
+	needInternalDepsErrors
+
+	// needInternalForTest adds the internal forTest field.
+	// Tests must also be set on the context for this field to be populated.
+	needInternalForTest
+
 	// typecheckCgo enables full support for type checking cgo. Requires Go 1.15+.
 	// Modifies CompiledGoFiles and Types, and has no effect on its own.
 	typecheckCgo
 
 	// NeedModule adds Module.
 	NeedModule
+
+	// NeedEmbedFiles adds EmbedFiles.
+	NeedEmbedFiles
+
+	// NeedEmbedPatterns adds EmbedPatterns.
+	NeedEmbedPatterns
 )
 
 const (
@@ -102,6 +113,9 @@ const (
 	// Deprecated: LoadAllSyntax exists for historical compatibility
 	// and should not be used. Please directly specify the needed fields using the Need values.
 	LoadAllSyntax = LoadSyntax | NeedDeps
+
+	// Deprecated: NeedExportsFile is a historical misspelling of NeedExportFile.
+	NeedExportsFile = NeedExportFile
 )
 
 // A Config specifies details about how packages should be loaded.
@@ -192,36 +206,6 @@ type Config struct {
 	Overlay map[string][]byte
 }
 
-// driver is the type for functions that query the build system for the
-// packages named by the patterns.
-type driver func(cfg *Config, patterns ...string) (*driverResponse, error)
-
-// driverResponse contains the results for a driver query.
-type driverResponse struct {
-	// NotHandled is returned if the request can't be handled by the current
-	// driver. If an external driver returns a response with NotHandled, the
-	// rest of the driverResponse is ignored, and go/packages will fallback
-	// to the next driver. If go/packages is extended in the future to support
-	// lists of multiple drivers, go/packages will fall back to the next driver.
-	NotHandled bool
-
-	// Sizes, if not nil, is the types.Sizes to use when type checking.
-	Sizes *types.StdSizes
-
-	// Roots is the set of package IDs that make up the root packages.
-	// We have to encode this separately because when we encode a single package
-	// we cannot know if it is one of the roots as that requires knowledge of the
-	// graph it is part of.
-	Roots []string `json:",omitempty"`
-
-	// Packages is the full set of packages in the graph.
-	// The packages are not connected into a graph.
-	// The Imports if populated will be stubs that only have their ID set.
-	// Imports will be connected and then type and syntax information added in a
-	// later pass (see refine).
-	Packages []*Package
-}
-
 // Load loads and returns the Go packages named by the given patterns.
 //
 // Config specifies loading options;
@@ -237,31 +221,55 @@ type driverResponse struct {
 // proceeding with further analysis. The PrintErrors function is
 // provided for convenient display of all errors.
 func Load(cfg *Config, patterns ...string) ([]*Package, error) {
-	l := newLoader(cfg)
-	response, err := defaultDriver(&l.Config, patterns...)
+	ld := newLoader(cfg)
+	response, external, err := defaultDriver(&ld.Config, patterns...)
 	if err != nil {
 		return nil, err
 	}
-	l.sizes = response.Sizes
-	return l.refine(response.Roots, response.Packages...)
+
+	ld.sizes = types.SizesFor(response.Compiler, response.Arch)
+	if ld.sizes == nil && ld.Config.Mode&(NeedTypes|NeedTypesSizes|NeedTypesInfo) != 0 {
+		// Type size information is needed but unavailable.
+		if external {
+			// An external driver may fail to populate the Compiler/GOARCH fields,
+			// especially since they are relatively new (see #63700).
+			// Provide a sensible fallback in this case.
+			ld.sizes = types.SizesFor("gc", runtime.GOARCH)
+			if ld.sizes == nil { // gccgo-only arch
+				ld.sizes = types.SizesFor("gc", "amd64")
+			}
+		} else {
+			// Go list should never fail to deliver accurate size information.
+			// Reject the whole Load since the error is the same for every package.
+			return nil, fmt.Errorf("can't determine type sizes for compiler %q on GOARCH %q",
+				response.Compiler, response.Arch)
+		}
+	}
+
+	return ld.refine(response)
 }
 
 // defaultDriver is a driver that implements go/packages' fallback behavior.
 // It will try to request to an external driver, if one exists. If there's
 // no external driver, or the driver returns a response with NotHandled set,
 // defaultDriver will fall back to the go list driver.
-func defaultDriver(cfg *Config, patterns ...string) (*driverResponse, error) {
-	driver := findExternalDriver(cfg)
-	if driver == nil {
-		driver = goListDriver
+// The boolean result indicates that an external driver handled the request.
+func defaultDriver(cfg *Config, patterns ...string) (*DriverResponse, bool, error) {
+	if driver := findExternalDriver(cfg); driver != nil {
+		response, err := driver(cfg, patterns...)
+		if err != nil {
+			return nil, false, err
+		} else if !response.NotHandled {
+			return response, true, nil
+		}
+		// (fall through)
 	}
-	response, err := driver(cfg, patterns...)
+
+	response, err := goListDriver(cfg, patterns...)
 	if err != nil {
-		return response, err
-	} else if response.NotHandled {
-		return goListDriver(cfg, patterns...)
+		return nil, false, err
 	}
-	return response, nil
+	return response, false, nil
 }
 
 // A Package describes a loaded Go package.
@@ -284,7 +292,13 @@ type Package struct {
 	// of the package, or while parsing or type-checking its files.
 	Errors []Error
 
+	// TypeErrors contains the subset of errors produced during type checking.
+	TypeErrors []types.Error
+
 	// GoFiles lists the absolute file paths of the package's Go source files.
+	// It may include files that should not be compiled, for example because
+	// they contain non-matching build tags, are documentary pseudo-files such as
+	// unsafe/unsafe.go or builtin/builtin.go, or are subject to cgo preprocessing.
 	GoFiles []string
 
 	// CompiledGoFiles lists the absolute file paths of the package's source
@@ -296,6 +310,14 @@ type Package struct {
 	// including assembly, C, C++, Fortran, Objective-C, SWIG, and so on.
 	OtherFiles []string
 
+	// EmbedFiles lists the absolute file paths of the package's files
+	// embedded with go:embed.
+	EmbedFiles []string
+
+	// EmbedPatterns lists the absolute file patterns of the package's
+	// files embedded with go:embed.
+	EmbedPatterns []string
+
 	// IgnoredFiles lists source files that are not part of the package
 	// using the current build configuration but that might be part of
 	// the package using other build configurations.
@@ -328,6 +350,9 @@ type Package struct {
 	// The NeedSyntax LoadMode bit populates this field for packages matching the patterns.
 	// If NeedDeps and NeedImports are also set, this field will also be populated
 	// for dependencies.
+	//
+	// Syntax is kept in the same order as CompiledGoFiles, with the caveat that nils are
+	// removed.  If parsing returned nil, Syntax may be shorter than CompiledGoFiles.
 	Syntax []*ast.File
 
 	// TypesInfo provides type information about the package's syntax trees.
@@ -373,12 +398,6 @@ func init() {
 	packagesinternal.GetDepsErrors = func(p interface{}) []*packagesinternal.PackageError {
 		return p.(*Package).depsErrors
 	}
-	packagesinternal.GetGoCmdRunner = func(config interface{}) *gocommand.Runner {
-		return config.(*Config).gocmdRunner
-	}
-	packagesinternal.SetGoCmdRunner = func(config interface{}, runner *gocommand.Runner) {
-		config.(*Config).gocmdRunner = runner
-	}
 	packagesinternal.SetModFile = func(config interface{}, value string) {
 		config.(*Config).modFile = value
 	}
@@ -386,6 +405,8 @@ func init() {
 		config.(*Config).modFlag = value
 	}
 	packagesinternal.TypecheckCgo = int(typecheckCgo)
+	packagesinternal.DepsErrors = int(needInternalDepsErrors)
+	packagesinternal.ForTest = int(needInternalForTest)
 }
 
 // An Error describes a problem with a package's metadata, syntax, or types.
@@ -428,6 +449,8 @@ type flatPackage struct {
 	GoFiles         []string          `json:",omitempty"`
 	CompiledGoFiles []string          `json:",omitempty"`
 	OtherFiles      []string          `json:",omitempty"`
+	EmbedFiles      []string          `json:",omitempty"`
+	EmbedPatterns   []string          `json:",omitempty"`
 	IgnoredFiles    []string          `json:",omitempty"`
 	ExportFile      string            `json:",omitempty"`
 	Imports         map[string]string `json:",omitempty"`
@@ -451,6 +474,8 @@ func (p *Package) MarshalJSON() ([]byte, error) {
 		GoFiles:         p.GoFiles,
 		CompiledGoFiles: p.CompiledGoFiles,
 		OtherFiles:      p.OtherFiles,
+		EmbedFiles:      p.EmbedFiles,
+		EmbedPatterns:   p.EmbedPatterns,
 		IgnoredFiles:    p.IgnoredFiles,
 		ExportFile:      p.ExportFile,
 	}
@@ -478,6 +503,8 @@ func (p *Package) UnmarshalJSON(b []byte) error {
 		GoFiles:         flat.GoFiles,
 		CompiledGoFiles: flat.CompiledGoFiles,
 		OtherFiles:      flat.OtherFiles,
+		EmbedFiles:      flat.EmbedFiles,
+		EmbedPatterns:   flat.EmbedPatterns,
 		ExportFile:      flat.ExportFile,
 	}
 	if len(flat.Imports) > 0 {
@@ -500,13 +527,14 @@ type loaderPackage struct {
 	needsrc      bool  // load from source (Mode >= LoadTypes)
 	needtypes    bool  // type information is either requested or depended on
 	initial      bool  // package was matched by a pattern
+	goVersion    int   // minor version number of go command on PATH
 }
 
 // loader holds the working state of a single call to load.
 type loader struct {
 	pkgs map[string]*loaderPackage
 	Config
-	sizes        types.Sizes
+	sizes        types.Sizes // non-nil if needed by mode
 	parseCache   map[string]*parseValue
 	parseCacheMu sync.Mutex
 	exportMu     sync.Mutex // enforces mutual exclusion of exportdata operations
@@ -584,9 +612,10 @@ func newLoader(cfg *Config) *loader {
 	return ld
 }
 
-// refine connects the supplied packages into a graph and then adds type and
+// refine connects the supplied packages into a graph and then adds type
 // and syntax information as requested by the LoadMode.
-func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
+func (ld *loader) refine(response *DriverResponse) ([]*Package, error) {
+	roots := response.Roots
 	rootMap := make(map[string]int, len(roots))
 	for i, root := range roots {
 		rootMap[root] = i
@@ -594,7 +623,7 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 	ld.pkgs = make(map[string]*loaderPackage)
 	// first pass, fixup and build the map and roots
 	var initial = make([]*loaderPackage, len(roots))
-	for _, pkg := range list {
+	for _, pkg := range response.Packages {
 		rootIndex := -1
 		if i, found := rootMap[pkg.ID]; found {
 			rootIndex = i
@@ -611,11 +640,12 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 		needsrc := ((ld.Mode&(NeedSyntax|NeedTypesInfo) != 0 && (rootIndex >= 0 || ld.Mode&NeedDeps != 0)) ||
 			// ... or if we need types and the exportData is invalid. We fall back to (incompletely)
 			// typechecking packages from source if they fail to compile.
-			(ld.Mode&NeedTypes|NeedTypesInfo != 0 && exportDataInvalid)) && pkg.PkgPath != "unsafe"
+			(ld.Mode&(NeedTypes|NeedTypesInfo) != 0 && exportDataInvalid)) && pkg.PkgPath != "unsafe"
 		lpkg := &loaderPackage{
 			Package:   pkg,
 			needtypes: needtypes,
 			needsrc:   needsrc,
+			goVersion: response.GoVersion,
 		}
 		ld.pkgs[lpkg.ID] = lpkg
 		if rootIndex >= 0 {
@@ -629,39 +659,38 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 		}
 	}
 
-	// Materialize the import graph.
-
-	const (
-		white = 0 // new
-		grey  = 1 // in progress
-		black = 2 // complete
-	)
-
-	// visit traverses the import graph, depth-first,
-	// and materializes the graph as Packages.Imports.
-	//
-	// Valid imports are saved in the Packages.Import map.
-	// Invalid imports (cycles and missing nodes) are saved in the importErrors map.
-	// Thus, even in the presence of both kinds of errors, the Import graph remains a DAG.
-	//
-	// visit returns whether the package needs src or has a transitive
-	// dependency on a package that does. These are the only packages
-	// for which we load source code.
-	var stack []*loaderPackage
-	var visit func(lpkg *loaderPackage) bool
-	var srcPkgs []*loaderPackage
-	visit = func(lpkg *loaderPackage) bool {
-		switch lpkg.color {
-		case black:
-			return lpkg.needsrc
-		case grey:
-			panic("internal error: grey node")
-		}
-		lpkg.color = grey
-		stack = append(stack, lpkg) // push
-		stubs := lpkg.Imports       // the structure form has only stubs with the ID in the Imports
-		// If NeedImports isn't set, the imports fields will all be zeroed out.
-		if ld.Mode&NeedImports != 0 {
+	if ld.Mode&NeedImports != 0 {
+		// Materialize the import graph.
+
+		const (
+			white = 0 // new
+			grey  = 1 // in progress
+			black = 2 // complete
+		)
+
+		// visit traverses the import graph, depth-first,
+		// and materializes the graph as Packages.Imports.
+		//
+		// Valid imports are saved in the Packages.Import map.
+		// Invalid imports (cycles and missing nodes) are saved in the importErrors map.
+		// Thus, even in the presence of both kinds of errors,
+		// the Import graph remains a DAG.
+		//
+		// visit returns whether the package needs src or has a transitive
+		// dependency on a package that does. These are the only packages
+		// for which we load source code.
+		var stack []*loaderPackage
+		var visit func(lpkg *loaderPackage) bool
+		visit = func(lpkg *loaderPackage) bool {
+			switch lpkg.color {
+			case black:
+				return lpkg.needsrc
+			case grey:
+				panic("internal error: grey node")
+			}
+			lpkg.color = grey
+			stack = append(stack, lpkg) // push
+			stubs := lpkg.Imports       // the structure form has only stubs with the ID in the Imports
 			lpkg.Imports = make(map[string]*Package, len(stubs))
 			for importPath, ipkg := range stubs {
 				var importErr error
@@ -685,40 +714,39 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 				}
 				lpkg.Imports[importPath] = imp.Package
 			}
-		}
-		if lpkg.needsrc {
-			srcPkgs = append(srcPkgs, lpkg)
-		}
-		if ld.Mode&NeedTypesSizes != 0 {
-			lpkg.TypesSizes = ld.sizes
-		}
-		stack = stack[:len(stack)-1] // pop
-		lpkg.color = black
 
-		return lpkg.needsrc
-	}
+			// Complete type information is required for the
+			// immediate dependencies of each source package.
+			if lpkg.needsrc && ld.Mode&NeedTypes != 0 {
+				for _, ipkg := range lpkg.Imports {
+					ld.pkgs[ipkg.ID].needtypes = true
+				}
+			}
 
-	if ld.Mode&NeedImports == 0 {
-		// We do this to drop the stub import packages that we are not even going to try to resolve.
-		for _, lpkg := range initial {
-			lpkg.Imports = nil
+			// NeedTypeSizes causes TypeSizes to be set even
+			// on packages for which types aren't needed.
+			if ld.Mode&NeedTypesSizes != 0 {
+				lpkg.TypesSizes = ld.sizes
+			}
+			stack = stack[:len(stack)-1] // pop
+			lpkg.color = black
+
+			return lpkg.needsrc
 		}
-	} else {
+
 		// For each initial package, create its import DAG.
 		for _, lpkg := range initial {
 			visit(lpkg)
 		}
-	}
-	if ld.Mode&NeedImports != 0 && ld.Mode&NeedTypes != 0 {
-		for _, lpkg := range srcPkgs {
-			// Complete type information is required for the
-			// immediate dependencies of each source package.
-			for _, ipkg := range lpkg.Imports {
-				imp := ld.pkgs[ipkg.ID]
-				imp.needtypes = true
-			}
+
+	} else {
+		// !NeedImports: drop the stub (ID-only) import packages
+		// that we are not even going to try to resolve.
+		for _, lpkg := range initial {
+			lpkg.Imports = nil
 		}
 	}
+
 	// Load type data and syntax if needed, starting at
 	// the initial packages (roots of the import DAG).
 	if ld.Mode&NeedTypes != 0 || ld.Mode&NeedSyntax != 0 {
@@ -749,13 +777,19 @@ func (ld *loader) refine(roots []string, list ...*Package) ([]*Package, error) {
 			ld.pkgs[i].OtherFiles = nil
 			ld.pkgs[i].IgnoredFiles = nil
 		}
+		if ld.requestedMode&NeedEmbedFiles == 0 {
+			ld.pkgs[i].EmbedFiles = nil
+		}
+		if ld.requestedMode&NeedEmbedPatterns == 0 {
+			ld.pkgs[i].EmbedPatterns = nil
+		}
 		if ld.requestedMode&NeedCompiledGoFiles == 0 {
 			ld.pkgs[i].CompiledGoFiles = nil
 		}
 		if ld.requestedMode&NeedImports == 0 {
 			ld.pkgs[i].Imports = nil
 		}
-		if ld.requestedMode&NeedExportsFile == 0 {
+		if ld.requestedMode&NeedExportFile == 0 {
 			ld.pkgs[i].ExportFile = ""
 		}
 		if ld.requestedMode&NeedTypes == 0 {
@@ -827,12 +861,19 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 	// never has to create a types.Package for an indirect dependency,
 	// which would then require that such created packages be explicitly
 	// inserted back into the Import graph as a final step after export data loading.
+	// (Hence this return is after the Types assignment.)
 	// The Diamond test exercises this case.
 	if !lpkg.needtypes && !lpkg.needsrc {
 		return
 	}
 	if !lpkg.needsrc {
-		ld.loadFromExportData(lpkg)
+		if err := ld.loadFromExportData(lpkg); err != nil {
+			lpkg.Errors = append(lpkg.Errors, Error{
+				Pos:  "-",
+				Msg:  err.Error(),
+				Kind: UnknownError, // e.g. can't find/open/parse export data
+			})
+		}
 		return // not a source package, don't get syntax trees
 	}
 
@@ -864,6 +905,7 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 
 		case types.Error:
 			// from type checker
+			lpkg.TypeErrors = append(lpkg.TypeErrors, err)
 			errs = append(errs, Error{
 				Pos:  err.Fset.Position(err.Pos).String(),
 				Msg:  err.Msg,
@@ -885,11 +927,41 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 		lpkg.Errors = append(lpkg.Errors, errs...)
 	}
 
+	// If the go command on the PATH is newer than the runtime,
+	// then the go/{scanner,ast,parser,types} packages from the
+	// standard library may be unable to process the files
+	// selected by go list.
+	//
+	// There is currently no way to downgrade the effective
+	// version of the go command (see issue 52078), so we proceed
+	// with the newer go command but, in case of parse or type
+	// errors, we emit an additional diagnostic.
+	//
+	// See:
+	// - golang.org/issue/52078 (flag to set release tags)
+	// - golang.org/issue/50825 (gopls legacy version support)
+	// - golang.org/issue/55883 (go/packages confusing error)
+	//
+	// Should we assert a hard minimum of (currently) go1.16 here?
+	var runtimeVersion int
+	if _, err := fmt.Sscanf(runtime.Version(), "go1.%d", &runtimeVersion); err == nil && runtimeVersion < lpkg.goVersion {
+		defer func() {
+			if len(lpkg.Errors) > 0 {
+				appendError(Error{
+					Pos:  "-",
+					Msg:  fmt.Sprintf("This application uses version go1.%d of the source-processing packages but runs version go1.%d of 'go list'. It may fail to process source files that rely on newer language features. If so, rebuild the application using a newer version of Go.", runtimeVersion, lpkg.goVersion),
+					Kind: UnknownError,
+				})
+			}
+		}()
+	}
+
 	if ld.Config.Mode&NeedTypes != 0 && len(lpkg.CompiledGoFiles) == 0 && lpkg.ExportFile != "" {
 		// The config requested loading sources and types, but sources are missing.
 		// Add an error to the package and fall back to loading from export data.
 		appendError(Error{"-", fmt.Sprintf("sources missing for package %s", lpkg.ID), ParseError})
-		ld.loadFromExportData(lpkg)
+		_ = ld.loadFromExportData(lpkg) // ignore any secondary errors
+
 		return // can't get syntax trees for this package
 	}
 
@@ -908,10 +980,11 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 		Defs:       make(map[*ast.Ident]types.Object),
 		Uses:       make(map[*ast.Ident]types.Object),
 		Implicits:  make(map[ast.Node]types.Object),
+		Instances:  make(map[*ast.Ident]types.Instance),
 		Scopes:     make(map[ast.Node]*types.Scope),
 		Selections: make(map[*ast.SelectorExpr]*types.Selection),
 	}
-	typeparams.InitInstanceInfo(lpkg.TypesInfo)
+	versions.InitFileVersions(lpkg.TypesInfo)
 	lpkg.TypesSizes = ld.sizes
 
 	importer := importerFunc(func(path string) (*types.Package, error) {
@@ -943,13 +1016,16 @@ func (ld *loader) loadPackage(lpkg *loaderPackage) {
 	tc := &types.Config{
 		Importer: importer,
 
-		// Type-check bodies of functions only in non-initial packages.
+		// Type-check bodies of functions only in initial packages.
 		// Example: for import graph A->B->C and initial packages {A,C},
 		// we can ignore function bodies in B.
 		IgnoreFuncBodies: ld.Mode&NeedDeps == 0 && !lpkg.initial,
 
 		Error: appendError,
-		Sizes: ld.sizes,
+		Sizes: ld.sizes, // may be nil
+	}
+	if lpkg.Module != nil && lpkg.Module.GoVersion != "" {
+		typesinternal.SetGoVersion(tc, "go"+lpkg.Module.GoVersion)
 	}
 	if (ld.Mode & typecheckCgo) != 0 {
 		if !typesinternal.SetUsesCgo(tc) {
@@ -1030,7 +1106,7 @@ func (ld *loader) parseFile(filename string) (*ast.File, error) {
 		var err error
 		if src == nil {
 			ioLimit <- true // wait
-			src, err = ioutil.ReadFile(filename)
+			src, err = os.ReadFile(filename)
 			<-ioLimit // signal
 		}
 		if err != nil {
@@ -1050,7 +1126,6 @@ func (ld *loader) parseFile(filename string) (*ast.File, error) {
 //
 // Because files are scanned in parallel, the token.Pos
 // positions of the resulting ast.Files are not ordered.
-//
 func (ld *loader) parseFiles(filenames []string) ([]*ast.File, []error) {
 	var wg sync.WaitGroup
 	n := len(filenames)
@@ -1094,7 +1169,6 @@ func (ld *loader) parseFiles(filenames []string) ([]*ast.File, []error) {
 
 // sameFile returns true if x and y have the same basename and denote
 // the same file.
-//
 func sameFile(x, y string) bool {
 	if x == y {
 		// It could be the case that y doesn't exist.
@@ -1115,9 +1189,10 @@ func sameFile(x, y string) bool {
 	return false
 }
 
-// loadFromExportData returns type information for the specified
+// loadFromExportData ensures that type information is present for the specified
 // package, loading it from an export data file on the first request.
-func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error) {
+// On success it sets lpkg.Types to a new Package.
+func (ld *loader) loadFromExportData(lpkg *loaderPackage) error {
 	if lpkg.PkgPath == "" {
 		log.Fatalf("internal error: Package %s has no PkgPath", lpkg)
 	}
@@ -1128,8 +1203,8 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 	// must be sequential. (Finer-grained locking would require
 	// changes to the gcexportdata API.)
 	//
-	// The exportMu lock guards the Package.Pkg field and the
-	// types.Package it points to, for each Package in the graph.
+	// The exportMu lock guards the lpkg.Types field and the
+	// types.Package it points to, for each loaderPackage in the graph.
 	//
 	// Not all accesses to Package.Pkg need to be protected by exportMu:
 	// graph ordering ensures that direct dependencies of source
@@ -1138,18 +1213,18 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 	defer ld.exportMu.Unlock()
 
 	if tpkg := lpkg.Types; tpkg != nil && tpkg.Complete() {
-		return tpkg, nil // cache hit
+		return nil // cache hit
 	}
 
 	lpkg.IllTyped = true // fail safe
 
 	if lpkg.ExportFile == "" {
 		// Errors while building export data will have been printed to stderr.
-		return nil, fmt.Errorf("no export data file")
+		return fmt.Errorf("no export data file")
 	}
 	f, err := os.Open(lpkg.ExportFile)
 	if err != nil {
-		return nil, err
+		return err
 	}
 	defer f.Close()
 
@@ -1161,7 +1236,7 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 	// queries.)
 	r, err := gcexportdata.NewReader(f)
 	if err != nil {
-		return nil, fmt.Errorf("reading %s: %v", lpkg.ExportFile, err)
+		return fmt.Errorf("reading %s: %v", lpkg.ExportFile, err)
 	}
 
 	// Build the view.
@@ -1205,31 +1280,26 @@ func (ld *loader) loadFromExportData(lpkg *loaderPackage) (*types.Package, error
 	// (May modify incomplete packages in view but not create new ones.)
 	tpkg, err := gcexportdata.Read(r, ld.Fset, view, lpkg.PkgPath)
 	if err != nil {
-		return nil, fmt.Errorf("reading %s: %v", lpkg.ExportFile, err)
+		return fmt.Errorf("reading %s: %v", lpkg.ExportFile, err)
+	}
+	if _, ok := view["go.shape"]; ok {
+		// Account for the pseudopackage "go.shape" that gets
+		// created by generic code.
+		viewLen++
 	}
 	if viewLen != len(view) {
-		log.Fatalf("Unexpected package creation during export data loading")
+		log.Panicf("golang.org/x/tools/go/packages: unexpected new packages during load of %s", lpkg.PkgPath)
 	}
 
 	lpkg.Types = tpkg
 	lpkg.IllTyped = false
-
-	return tpkg, nil
+	return nil
 }
 
 // impliedLoadMode returns loadMode with its dependencies.
 func impliedLoadMode(loadMode LoadMode) LoadMode {
-	if loadMode&NeedTypesInfo != 0 && loadMode&NeedImports == 0 {
-		// If NeedTypesInfo, go/packages needs to do typechecking itself so it can
-		// associate type info with the AST. To do so, we need the export data
-		// for dependencies, which means we need to ask for the direct dependencies.
-		// NeedImports is used to ask for the direct dependencies.
-		loadMode |= NeedImports
-	}
-
-	if loadMode&NeedDeps != 0 && loadMode&NeedImports == 0 {
-		// With NeedDeps we need to load at least direct dependencies.
-		// NeedImports is used to ask for the direct dependencies.
+	if loadMode&(NeedDeps|NeedTypes|NeedTypesInfo) != 0 {
+		// All these things require knowing the import graph.
 		loadMode |= NeedImports
 	}
 
@@ -1237,5 +1307,7 @@ func impliedLoadMode(loadMode LoadMode) LoadMode {
 }
 
 func usesExportData(cfg *Config) bool {
-	return cfg.Mode&NeedExportsFile != 0 || cfg.Mode&NeedTypes != 0 && cfg.Mode&NeedDeps == 0
+	return cfg.Mode&NeedExportFile != 0 || cfg.Mode&NeedTypes != 0 && cfg.Mode&NeedDeps == 0
 }
+
+var _ interface{} = io.Discard // assert build toolchain is go1.16 or later
diff --git a/vendor/golang.org/x/tools/internal/gocommand/invoke.go b/vendor/golang.org/x/tools/internal/gocommand/invoke.go
index 8659a0c..5531252 100644
--- a/vendor/golang.org/x/tools/internal/gocommand/invoke.go
+++ b/vendor/golang.org/x/tools/internal/gocommand/invoke.go
@@ -8,17 +8,24 @@ package gocommand
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
-	exec "golang.org/x/sys/execabs"
 	"io"
+	"log"
 	"os"
+	"os/exec"
+	"reflect"
 	"regexp"
+	"runtime"
 	"strconv"
 	"strings"
 	"sync"
 	"time"
 
 	"golang.org/x/tools/internal/event"
+	"golang.org/x/tools/internal/event/keys"
+	"golang.org/x/tools/internal/event/label"
+	"golang.org/x/tools/internal/event/tag"
 )
 
 // An Runner will run go command invocations and serialize
@@ -48,9 +55,19 @@ func (runner *Runner) initialize() {
 // 1.14: go: updating go.mod: existing contents have changed since last read
 var modConcurrencyError = regexp.MustCompile(`go:.*go.mod.*contents have changed`)
 
+// verb is an event label for the go command verb.
+var verb = keys.NewString("verb", "go command verb")
+
+func invLabels(inv Invocation) []label.Label {
+	return []label.Label{verb.Of(inv.Verb), tag.Directory.Of(inv.WorkingDir)}
+}
+
 // Run is a convenience wrapper around RunRaw.
 // It returns only stdout and a "friendly" error.
 func (runner *Runner) Run(ctx context.Context, inv Invocation) (*bytes.Buffer, error) {
+	ctx, done := event.Start(ctx, "gocommand.Runner.Run", invLabels(inv)...)
+	defer done()
+
 	stdout, _, friendly, _ := runner.RunRaw(ctx, inv)
 	return stdout, friendly
 }
@@ -58,13 +75,19 @@ func (runner *Runner) Run(ctx context.Context, inv Invocation) (*bytes.Buffer, e
 // RunPiped runs the invocation serially, always waiting for any concurrent
 // invocations to complete first.
 func (runner *Runner) RunPiped(ctx context.Context, inv Invocation, stdout, stderr io.Writer) error {
+	ctx, done := event.Start(ctx, "gocommand.Runner.RunPiped", invLabels(inv)...)
+	defer done()
+
 	_, err := runner.runPiped(ctx, inv, stdout, stderr)
 	return err
 }
 
 // RunRaw runs the invocation, serializing requests only if they fight over
 // go.mod changes.
+// Postcondition: both error results have same nilness.
 func (runner *Runner) RunRaw(ctx context.Context, inv Invocation) (*bytes.Buffer, *bytes.Buffer, error, error) {
+	ctx, done := event.Start(ctx, "gocommand.Runner.RunRaw", invLabels(inv)...)
+	defer done()
 	// Make sure the runner is always initialized.
 	runner.initialize()
 
@@ -72,23 +95,24 @@ func (runner *Runner) RunRaw(ctx context.Context, inv Invocation) (*bytes.Buffer
 	stdout, stderr, friendlyErr, err := runner.runConcurrent(ctx, inv)
 
 	// If we encounter a load concurrency error, we need to retry serially.
-	if friendlyErr == nil || !modConcurrencyError.MatchString(friendlyErr.Error()) {
-		return stdout, stderr, friendlyErr, err
+	if friendlyErr != nil && modConcurrencyError.MatchString(friendlyErr.Error()) {
+		event.Error(ctx, "Load concurrency error, will retry serially", err)
+
+		// Run serially by calling runPiped.
+		stdout.Reset()
+		stderr.Reset()
+		friendlyErr, err = runner.runPiped(ctx, inv, stdout, stderr)
 	}
-	event.Error(ctx, "Load concurrency error, will retry serially", err)
 
-	// Run serially by calling runPiped.
-	stdout.Reset()
-	stderr.Reset()
-	friendlyErr, err = runner.runPiped(ctx, inv, stdout, stderr)
 	return stdout, stderr, friendlyErr, err
 }
 
+// Postcondition: both error results have same nilness.
 func (runner *Runner) runConcurrent(ctx context.Context, inv Invocation) (*bytes.Buffer, *bytes.Buffer, error, error) {
 	// Wait for 1 worker to become available.
 	select {
 	case <-ctx.Done():
-		return nil, nil, nil, ctx.Err()
+		return nil, nil, ctx.Err(), ctx.Err()
 	case runner.inFlight <- struct{}{}:
 		defer func() { <-runner.inFlight }()
 	}
@@ -98,6 +122,7 @@ func (runner *Runner) runConcurrent(ctx context.Context, inv Invocation) (*bytes
 	return stdout, stderr, friendlyErr, err
 }
 
+// Postcondition: both error results have same nilness.
 func (runner *Runner) runPiped(ctx context.Context, inv Invocation, stdout, stderr io.Writer) (error, error) {
 	// Make sure the runner is always initialized.
 	runner.initialize()
@@ -106,7 +131,7 @@ func (runner *Runner) runPiped(ctx context.Context, inv Invocation, stdout, stde
 	// runPiped commands.
 	select {
 	case <-ctx.Done():
-		return nil, ctx.Err()
+		return ctx.Err(), ctx.Err()
 	case runner.serialized <- struct{}{}:
 		defer func() { <-runner.serialized }()
 	}
@@ -116,7 +141,7 @@ func (runner *Runner) runPiped(ctx context.Context, inv Invocation, stdout, stde
 	for i := 0; i < maxInFlight; i++ {
 		select {
 		case <-ctx.Done():
-			return nil, ctx.Err()
+			return ctx.Err(), ctx.Err()
 		case runner.inFlight <- struct{}{}:
 			// Make sure we always "return" any workers we took.
 			defer func() { <-runner.inFlight }()
@@ -131,9 +156,16 @@ type Invocation struct {
 	Verb       string
 	Args       []string
 	BuildFlags []string
-	ModFlag    string
-	ModFile    string
-	Overlay    string
+
+	// If ModFlag is set, the go command is invoked with -mod=ModFlag.
+	ModFlag string
+
+	// If ModFile is set, the go command is invoked with -modfile=ModFile.
+	ModFile string
+
+	// If Overlay is set, the go command is invoked with -overlay=Overlay.
+	Overlay string
+
 	// If CleanEnv is set, the invocation will run only with the environment
 	// in Env, not starting with os.Environ.
 	CleanEnv   bool
@@ -142,6 +174,7 @@ type Invocation struct {
 	Logf       func(format string, args ...interface{})
 }
 
+// Postcondition: both error results have same nilness.
 func (i *Invocation) runWithFriendlyError(ctx context.Context, stdout, stderr io.Writer) (friendlyError error, rawError error) {
 	rawError = i.run(ctx, stdout, stderr)
 	if rawError != nil {
@@ -205,6 +238,18 @@ func (i *Invocation) run(ctx context.Context, stdout, stderr io.Writer) error {
 	cmd := exec.Command("go", goArgs...)
 	cmd.Stdout = stdout
 	cmd.Stderr = stderr
+
+	// cmd.WaitDelay was added only in go1.20 (see #50436).
+	if waitDelay := reflect.ValueOf(cmd).Elem().FieldByName("WaitDelay"); waitDelay.IsValid() {
+		// https://go.dev/issue/59541: don't wait forever copying stderr
+		// after the command has exited.
+		// After CL 484741 we copy stdout manually, so we we'll stop reading that as
+		// soon as ctx is done. However, we also don't want to wait around forever
+		// for stderr. Give a much-longer-than-reasonable delay and then assume that
+		// something has wedged in the kernel or runtime.
+		waitDelay.Set(reflect.ValueOf(30 * time.Second))
+	}
+
 	// On darwin the cwd gets resolved to the real path, which breaks anything that
 	// expects the working directory to keep the original path, including the
 	// go command when dealing with modules.
@@ -219,45 +264,192 @@ func (i *Invocation) run(ctx context.Context, stdout, stderr io.Writer) error {
 		cmd.Env = append(cmd.Env, "PWD="+i.WorkingDir)
 		cmd.Dir = i.WorkingDir
 	}
+
 	defer func(start time.Time) { log("%s for %v", time.Since(start), cmdDebugStr(cmd)) }(time.Now())
 
 	return runCmdContext(ctx, cmd)
 }
 
+// DebugHangingGoCommands may be set by tests to enable additional
+// instrumentation (including panics) for debugging hanging Go commands.
+//
+// See golang/go#54461 for details.
+var DebugHangingGoCommands = false
+
 // runCmdContext is like exec.CommandContext except it sends os.Interrupt
 // before os.Kill.
-func runCmdContext(ctx context.Context, cmd *exec.Cmd) error {
-	if err := cmd.Start(); err != nil {
+func runCmdContext(ctx context.Context, cmd *exec.Cmd) (err error) {
+	// If cmd.Stdout is not an *os.File, the exec package will create a pipe and
+	// copy it to the Writer in a goroutine until the process has finished and
+	// either the pipe reaches EOF or command's WaitDelay expires.
+	//
+	// However, the output from 'go list' can be quite large, and we don't want to
+	// keep reading (and allocating buffers) if we've already decided we don't
+	// care about the output. We don't want to wait for the process to finish, and
+	// we don't wait to wait for the WaitDelay to expire either.
+	//
+	// Instead, if cmd.Stdout requires a copying goroutine we explicitly replace
+	// it with a pipe (which is an *os.File), which we can close in order to stop
+	// copying output as soon as we realize we don't care about it.
+	var stdoutW *os.File
+	if cmd.Stdout != nil {
+		if _, ok := cmd.Stdout.(*os.File); !ok {
+			var stdoutR *os.File
+			stdoutR, stdoutW, err = os.Pipe()
+			if err != nil {
+				return err
+			}
+			prevStdout := cmd.Stdout
+			cmd.Stdout = stdoutW
+
+			stdoutErr := make(chan error, 1)
+			go func() {
+				_, err := io.Copy(prevStdout, stdoutR)
+				if err != nil {
+					err = fmt.Errorf("copying stdout: %w", err)
+				}
+				stdoutErr <- err
+			}()
+			defer func() {
+				// We started a goroutine to copy a stdout pipe.
+				// Wait for it to finish, or terminate it if need be.
+				var err2 error
+				select {
+				case err2 = <-stdoutErr:
+					stdoutR.Close()
+				case <-ctx.Done():
+					stdoutR.Close()
+					// Per https://pkg.go.dev/os#File.Close, the call to stdoutR.Close
+					// should cause the Read call in io.Copy to unblock and return
+					// immediately, but we still need to receive from stdoutErr to confirm
+					// that it has happened.
+					<-stdoutErr
+					err2 = ctx.Err()
+				}
+				if err == nil {
+					err = err2
+				}
+			}()
+
+			// Per https://pkg.go.dev/os/exec#Cmd, “If Stdout and Stderr are the
+			// same writer, and have a type that can be compared with ==, at most
+			// one goroutine at a time will call Write.”
+			//
+			// Since we're starting a goroutine that writes to cmd.Stdout, we must
+			// also update cmd.Stderr so that it still holds.
+			func() {
+				defer func() { recover() }()
+				if cmd.Stderr == prevStdout {
+					cmd.Stderr = cmd.Stdout
+				}
+			}()
+		}
+	}
+
+	err = cmd.Start()
+	if stdoutW != nil {
+		// The child process has inherited the pipe file,
+		// so close the copy held in this process.
+		stdoutW.Close()
+		stdoutW = nil
+	}
+	if err != nil {
 		return err
 	}
+
 	resChan := make(chan error, 1)
 	go func() {
 		resChan <- cmd.Wait()
 	}()
 
-	select {
-	case err := <-resChan:
-		return err
-	case <-ctx.Done():
+	// If we're interested in debugging hanging Go commands, stop waiting after a
+	// minute and panic with interesting information.
+	debug := DebugHangingGoCommands
+	if debug {
+		timer := time.NewTimer(1 * time.Minute)
+		defer timer.Stop()
+		select {
+		case err := <-resChan:
+			return err
+		case <-timer.C:
+			HandleHangingGoCommand(cmd.Process)
+		case <-ctx.Done():
+		}
+	} else {
+		select {
+		case err := <-resChan:
+			return err
+		case <-ctx.Done():
+		}
 	}
+
 	// Cancelled. Interrupt and see if it ends voluntarily.
-	cmd.Process.Signal(os.Interrupt)
-	select {
-	case err := <-resChan:
-		return err
-	case <-time.After(time.Second):
+	if err := cmd.Process.Signal(os.Interrupt); err == nil {
+		// (We used to wait only 1s but this proved
+		// fragile on loaded builder machines.)
+		timer := time.NewTimer(5 * time.Second)
+		defer timer.Stop()
+		select {
+		case err := <-resChan:
+			return err
+		case <-timer.C:
+		}
 	}
+
 	// Didn't shut down in response to interrupt. Kill it hard.
-	cmd.Process.Kill()
+	// TODO(rfindley): per advice from bcmills@, it may be better to send SIGQUIT
+	// on certain platforms, such as unix.
+	if err := cmd.Process.Kill(); err != nil && !errors.Is(err, os.ErrProcessDone) && debug {
+		log.Printf("error killing the Go command: %v", err)
+	}
+
 	return <-resChan
 }
 
+func HandleHangingGoCommand(proc *os.Process) {
+	switch runtime.GOOS {
+	case "linux", "darwin", "freebsd", "netbsd":
+		fmt.Fprintln(os.Stderr, `DETECTED A HANGING GO COMMAND
+
+The gopls test runner has detected a hanging go command. In order to debug
+this, the output of ps and lsof/fstat is printed below.
+
+See golang/go#54461 for more details.`)
+
+		fmt.Fprintln(os.Stderr, "\nps axo ppid,pid,command:")
+		fmt.Fprintln(os.Stderr, "-------------------------")
+		psCmd := exec.Command("ps", "axo", "ppid,pid,command")
+		psCmd.Stdout = os.Stderr
+		psCmd.Stderr = os.Stderr
+		if err := psCmd.Run(); err != nil {
+			panic(fmt.Sprintf("running ps: %v", err))
+		}
+
+		listFiles := "lsof"
+		if runtime.GOOS == "freebsd" || runtime.GOOS == "netbsd" {
+			listFiles = "fstat"
+		}
+
+		fmt.Fprintln(os.Stderr, "\n"+listFiles+":")
+		fmt.Fprintln(os.Stderr, "-----")
+		listFilesCmd := exec.Command(listFiles)
+		listFilesCmd.Stdout = os.Stderr
+		listFilesCmd.Stderr = os.Stderr
+		if err := listFilesCmd.Run(); err != nil {
+			panic(fmt.Sprintf("running %s: %v", listFiles, err))
+		}
+	}
+	panic(fmt.Sprintf("detected hanging go command (pid %d): see golang/go#54461 for more details", proc.Pid))
+}
+
 func cmdDebugStr(cmd *exec.Cmd) string {
 	env := make(map[string]string)
 	for _, kv := range cmd.Env {
 		split := strings.SplitN(kv, "=", 2)
-		k, v := split[0], split[1]
-		env[k] = v
+		if len(split) == 2 {
+			k, v := split[0], split[1]
+			env[k] = v
+		}
 	}
 
 	var args []string
diff --git a/vendor/golang.org/x/tools/internal/gocommand/vendor.go b/vendor/golang.org/x/tools/internal/gocommand/vendor.go
index 5e75bd6..2d3d408 100644
--- a/vendor/golang.org/x/tools/internal/gocommand/vendor.go
+++ b/vendor/golang.org/x/tools/internal/gocommand/vendor.go
@@ -38,10 +38,10 @@ var modFlagRegexp = regexp.MustCompile(`-mod[ =](\w+)`)
 // with the supplied context.Context and Invocation. The Invocation can contain pre-defined fields,
 // of which only Verb and Args are modified to run the appropriate Go command.
 // Inspired by setDefaultBuildMod in modload/init.go
-func VendorEnabled(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON, bool, error) {
+func VendorEnabled(ctx context.Context, inv Invocation, r *Runner) (bool, *ModuleJSON, error) {
 	mainMod, go114, err := getMainModuleAnd114(ctx, inv, r)
 	if err != nil {
-		return nil, false, err
+		return false, nil, err
 	}
 
 	// We check the GOFLAGS to see if there is anything overridden or not.
@@ -49,7 +49,7 @@ func VendorEnabled(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON,
 	inv.Args = []string{"GOFLAGS"}
 	stdout, err := r.Run(ctx, inv)
 	if err != nil {
-		return nil, false, err
+		return false, nil, err
 	}
 	goflags := string(bytes.TrimSpace(stdout.Bytes()))
 	matches := modFlagRegexp.FindStringSubmatch(goflags)
@@ -57,25 +57,27 @@ func VendorEnabled(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON,
 	if len(matches) != 0 {
 		modFlag = matches[1]
 	}
-	if modFlag != "" {
-		// Don't override an explicit '-mod=' argument.
-		return mainMod, modFlag == "vendor", nil
+	// Don't override an explicit '-mod=' argument.
+	if modFlag == "vendor" {
+		return true, mainMod, nil
+	} else if modFlag != "" {
+		return false, nil, nil
 	}
 	if mainMod == nil || !go114 {
-		return mainMod, false, nil
+		return false, nil, nil
 	}
 	// Check 1.14's automatic vendor mode.
 	if fi, err := os.Stat(filepath.Join(mainMod.Dir, "vendor")); err == nil && fi.IsDir() {
 		if mainMod.GoVersion != "" && semver.Compare("v"+mainMod.GoVersion, "v1.14") >= 0 {
 			// The Go version is at least 1.14, and a vendor directory exists.
 			// Set -mod=vendor by default.
-			return mainMod, true, nil
+			return true, mainMod, nil
 		}
 	}
-	return mainMod, false, nil
+	return false, nil, nil
 }
 
-// getMainModuleAnd114 gets the main module's information and whether the
+// getMainModuleAnd114 gets one of the main modules' information and whether the
 // go command in use is 1.14+. This is the information needed to figure out
 // if vendoring should be enabled.
 func getMainModuleAnd114(ctx context.Context, inv Invocation, r *Runner) (*ModuleJSON, bool, error) {
diff --git a/vendor/golang.org/x/tools/internal/gocommand/version.go b/vendor/golang.org/x/tools/internal/gocommand/version.go
index 7130436..446c584 100644
--- a/vendor/golang.org/x/tools/internal/gocommand/version.go
+++ b/vendor/golang.org/x/tools/internal/gocommand/version.go
@@ -7,29 +7,27 @@ package gocommand
 import (
 	"context"
 	"fmt"
+	"regexp"
 	"strings"
 )
 
-// GoVersion checks the go version by running "go list" with modules off.
-// It returns the X in Go 1.X.
+// GoVersion reports the minor version number of the highest release
+// tag built into the go command on the PATH.
+//
+// Note that this may be higher than the version of the go tool used
+// to build this application, and thus the versions of the standard
+// go/{scanner,parser,ast,types} packages that are linked into it.
+// In that case, callers should either downgrade to the version of
+// go used to build the application, or report an error that the
+// application is too old to use the go command on the PATH.
 func GoVersion(ctx context.Context, inv Invocation, r *Runner) (int, error) {
 	inv.Verb = "list"
 	inv.Args = []string{"-e", "-f", `{{context.ReleaseTags}}`, `--`, `unsafe`}
-	inv.Env = append(append([]string{}, inv.Env...), "GO111MODULE=off")
-	// Unset any unneeded flags, and remove them from BuildFlags, if they're
-	// present.
-	inv.ModFile = ""
+	inv.BuildFlags = nil // This is not a build command.
 	inv.ModFlag = ""
-	var buildFlags []string
-	for _, flag := range inv.BuildFlags {
-		// Flags can be prefixed by one or two dashes.
-		f := strings.TrimPrefix(strings.TrimPrefix(flag, "-"), "-")
-		if strings.HasPrefix(f, "mod=") || strings.HasPrefix(f, "modfile=") {
-			continue
-		}
-		buildFlags = append(buildFlags, flag)
-	}
-	inv.BuildFlags = buildFlags
+	inv.ModFile = ""
+	inv.Env = append(inv.Env[:len(inv.Env):len(inv.Env)], "GO111MODULE=off")
+
 	stdoutBytes, err := r.Run(ctx, inv)
 	if err != nil {
 		return 0, err
@@ -38,7 +36,7 @@ func GoVersion(ctx context.Context, inv Invocation, r *Runner) (int, error) {
 	if len(stdout) < 3 {
 		return 0, fmt.Errorf("bad ReleaseTags output: %q", stdout)
 	}
-	// Split up "[go1.1 go1.15]"
+	// Split up "[go1.1 go1.15]" and return highest go1.X value.
 	tags := strings.Fields(stdout[1 : len(stdout)-2])
 	for i := len(tags) - 1; i >= 0; i-- {
 		var version int
@@ -49,3 +47,25 @@ func GoVersion(ctx context.Context, inv Invocation, r *Runner) (int, error) {
 	}
 	return 0, fmt.Errorf("no parseable ReleaseTags in %v", tags)
 }
+
+// GoVersionOutput returns the complete output of the go version command.
+func GoVersionOutput(ctx context.Context, inv Invocation, r *Runner) (string, error) {
+	inv.Verb = "version"
+	goVersion, err := r.Run(ctx, inv)
+	if err != nil {
+		return "", err
+	}
+	return goVersion.String(), nil
+}
+
+// ParseGoVersionOutput extracts the Go version string
+// from the output of the "go version" command.
+// Given an unrecognized form, it returns an empty string.
+func ParseGoVersionOutput(data string) string {
+	re := regexp.MustCompile(`^go version (go\S+|devel \S+)`)
+	m := re.FindStringSubmatch(data)
+	if len(m) != 2 {
+		return "" // unrecognized version
+	}
+	return m[1]
+}
diff --git a/vendor/golang.org/x/tools/internal/packagesinternal/packages.go b/vendor/golang.org/x/tools/internal/packagesinternal/packages.go
index 9702094..44719de 100644
--- a/vendor/golang.org/x/tools/internal/packagesinternal/packages.go
+++ b/vendor/golang.org/x/tools/internal/packagesinternal/packages.go
@@ -5,10 +5,6 @@
 // Package packagesinternal exposes internal-only fields from go/packages.
 package packagesinternal
 
-import (
-	"golang.org/x/tools/internal/gocommand"
-)
-
 var GetForTest = func(p interface{}) string { return "" }
 var GetDepsErrors = func(p interface{}) []*PackageError { return nil }
 
@@ -18,11 +14,9 @@ type PackageError struct {
 	Err         string   // the error itself
 }
 
-var GetGoCmdRunner = func(config interface{}) *gocommand.Runner { return nil }
-
-var SetGoCmdRunner = func(config interface{}, runner *gocommand.Runner) {}
-
 var TypecheckCgo int
+var DepsErrors int // must be set as a LoadMode to call GetDepsErrors
+var ForTest int    // must be set as a LoadMode to call GetForTest
 
 var SetModFlag = func(config interface{}, value string) {}
 var SetModFile = func(config interface{}, value string) {}
diff --git a/vendor/golang.org/x/tools/internal/typeparams/common.go b/vendor/golang.org/x/tools/internal/typeparams/common.go
index 961d036..cdab988 100644
--- a/vendor/golang.org/x/tools/internal/typeparams/common.go
+++ b/vendor/golang.org/x/tools/internal/typeparams/common.go
@@ -2,31 +2,203 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package typeparams provides functions to work indirectly with type parameter
-// data stored in go/ast and go/types objects, while these API are guarded by a
-// build constraint.
+// Package typeparams contains common utilities for writing tools that interact
+// with generic Go code, as introduced with Go 1.18.
 //
-// This package exists to make it easier for tools to work with generic code,
-// while also compiling against older Go versions.
+// Many of the types and functions in this package are proxies for the new APIs
+// introduced in the standard library with Go 1.18. For example, the
+// typeparams.Union type is an alias for go/types.Union, and the ForTypeSpec
+// function returns the value of the go/ast.TypeSpec.TypeParams field. At Go
+// versions older than 1.18 these helpers are implemented as stubs, allowing
+// users of this package to write code that handles generic constructs inline,
+// even if the Go version being used to compile does not support generics.
+//
+// Additionally, this package contains common utilities for working with the
+// new generic constructs, to supplement the standard library APIs. Notably,
+// the StructuralTerms API computes a minimal representation of the structural
+// restrictions on a type parameter.
+//
+// An external version of these APIs is available in the
+// golang.org/x/exp/typeparams module.
 package typeparams
 
 import (
+	"fmt"
 	"go/ast"
 	"go/token"
 	"go/types"
 )
 
-// A IndexExprData holds data from both ast.IndexExpr and the new
-// ast.MultiIndexExpr, which was introduced in Go 1.18.
-type IndexExprData struct {
-	X       ast.Expr   // expression
-	Lbrack  token.Pos  // position of "["
-	Indices []ast.Expr // index expressions
-	Rbrack  token.Pos  // position of "]"
+// UnpackIndexExpr extracts data from AST nodes that represent index
+// expressions.
+//
+// For an ast.IndexExpr, the resulting indices slice will contain exactly one
+// index expression. For an ast.IndexListExpr (go1.18+), it may have a variable
+// number of index expressions.
+//
+// For nodes that don't represent index expressions, the first return value of
+// UnpackIndexExpr will be nil.
+func UnpackIndexExpr(n ast.Node) (x ast.Expr, lbrack token.Pos, indices []ast.Expr, rbrack token.Pos) {
+	switch e := n.(type) {
+	case *ast.IndexExpr:
+		return e.X, e.Lbrack, []ast.Expr{e.Index}, e.Rbrack
+	case *ast.IndexListExpr:
+		return e.X, e.Lbrack, e.Indices, e.Rbrack
+	}
+	return nil, token.NoPos, nil, token.NoPos
+}
+
+// PackIndexExpr returns an *ast.IndexExpr or *ast.IndexListExpr, depending on
+// the cardinality of indices. Calling PackIndexExpr with len(indices) == 0
+// will panic.
+func PackIndexExpr(x ast.Expr, lbrack token.Pos, indices []ast.Expr, rbrack token.Pos) ast.Expr {
+	switch len(indices) {
+	case 0:
+		panic("empty indices")
+	case 1:
+		return &ast.IndexExpr{
+			X:      x,
+			Lbrack: lbrack,
+			Index:  indices[0],
+			Rbrack: rbrack,
+		}
+	default:
+		return &ast.IndexListExpr{
+			X:       x,
+			Lbrack:  lbrack,
+			Indices: indices,
+			Rbrack:  rbrack,
+		}
+	}
 }
 
 // IsTypeParam reports whether t is a type parameter.
 func IsTypeParam(t types.Type) bool {
-	_, ok := t.(*TypeParam)
+	_, ok := t.(*types.TypeParam)
 	return ok
 }
+
+// OriginMethod returns the origin method associated with the method fn.
+// For methods on a non-generic receiver base type, this is just
+// fn. However, for methods with a generic receiver, OriginMethod returns the
+// corresponding method in the method set of the origin type.
+//
+// As a special case, if fn is not a method (has no receiver), OriginMethod
+// returns fn.
+func OriginMethod(fn *types.Func) *types.Func {
+	recv := fn.Type().(*types.Signature).Recv()
+	if recv == nil {
+		return fn
+	}
+	base := recv.Type()
+	p, isPtr := base.(*types.Pointer)
+	if isPtr {
+		base = p.Elem()
+	}
+	named, isNamed := base.(*types.Named)
+	if !isNamed {
+		// Receiver is a *types.Interface.
+		return fn
+	}
+	if named.TypeParams().Len() == 0 {
+		// Receiver base has no type parameters, so we can avoid the lookup below.
+		return fn
+	}
+	orig := named.Origin()
+	gfn, _, _ := types.LookupFieldOrMethod(orig, true, fn.Pkg(), fn.Name())
+
+	// This is a fix for a gopls crash (#60628) due to a go/types bug (#60634). In:
+	// 	package p
+	//      type T *int
+	//      func (*T) f() {}
+	// LookupFieldOrMethod(T, true, p, f)=nil, but NewMethodSet(*T)={(*T).f}.
+	// Here we make them consistent by force.
+	// (The go/types bug is general, but this workaround is reached only
+	// for generic T thanks to the early return above.)
+	if gfn == nil {
+		mset := types.NewMethodSet(types.NewPointer(orig))
+		for i := 0; i < mset.Len(); i++ {
+			m := mset.At(i)
+			if m.Obj().Id() == fn.Id() {
+				gfn = m.Obj()
+				break
+			}
+		}
+	}
+
+	// In golang/go#61196, we observe another crash, this time inexplicable.
+	if gfn == nil {
+		panic(fmt.Sprintf("missing origin method for %s.%s; named == origin: %t, named.NumMethods(): %d, origin.NumMethods(): %d", named, fn, named == orig, named.NumMethods(), orig.NumMethods()))
+	}
+
+	return gfn.(*types.Func)
+}
+
+// GenericAssignableTo is a generalization of types.AssignableTo that
+// implements the following rule for uninstantiated generic types:
+//
+// If V and T are generic named types, then V is considered assignable to T if,
+// for every possible instantation of V[A_1, ..., A_N], the instantiation
+// T[A_1, ..., A_N] is valid and V[A_1, ..., A_N] implements T[A_1, ..., A_N].
+//
+// If T has structural constraints, they must be satisfied by V.
+//
+// For example, consider the following type declarations:
+//
+//	type Interface[T any] interface {
+//		Accept(T)
+//	}
+//
+//	type Container[T any] struct {
+//		Element T
+//	}
+//
+//	func (c Container[T]) Accept(t T) { c.Element = t }
+//
+// In this case, GenericAssignableTo reports that instantiations of Container
+// are assignable to the corresponding instantiation of Interface.
+func GenericAssignableTo(ctxt *types.Context, V, T types.Type) bool {
+	// If V and T are not both named, or do not have matching non-empty type
+	// parameter lists, fall back on types.AssignableTo.
+
+	VN, Vnamed := V.(*types.Named)
+	TN, Tnamed := T.(*types.Named)
+	if !Vnamed || !Tnamed {
+		return types.AssignableTo(V, T)
+	}
+
+	vtparams := VN.TypeParams()
+	ttparams := TN.TypeParams()
+	if vtparams.Len() == 0 || vtparams.Len() != ttparams.Len() || VN.TypeArgs().Len() != 0 || TN.TypeArgs().Len() != 0 {
+		return types.AssignableTo(V, T)
+	}
+
+	// V and T have the same (non-zero) number of type params. Instantiate both
+	// with the type parameters of V. This must always succeed for V, and will
+	// succeed for T if and only if the type set of each type parameter of V is a
+	// subset of the type set of the corresponding type parameter of T, meaning
+	// that every instantiation of V corresponds to a valid instantiation of T.
+
+	// Minor optimization: ensure we share a context across the two
+	// instantiations below.
+	if ctxt == nil {
+		ctxt = types.NewContext()
+	}
+
+	var targs []types.Type
+	for i := 0; i < vtparams.Len(); i++ {
+		targs = append(targs, vtparams.At(i))
+	}
+
+	vinst, err := types.Instantiate(ctxt, V, targs, true)
+	if err != nil {
+		panic("type parameters should satisfy their own constraints")
+	}
+
+	tinst, err := types.Instantiate(ctxt, T, targs, true)
+	if err != nil {
+		return false
+	}
+
+	return types.AssignableTo(vinst, tinst)
+}
diff --git a/vendor/golang.org/x/tools/internal/typeparams/enabled_go117.go b/vendor/golang.org/x/tools/internal/typeparams/enabled_go117.go
deleted file mode 100644
index 1821239..0000000
--- a/vendor/golang.org/x/tools/internal/typeparams/enabled_go117.go
+++ /dev/null
@@ -1,12 +0,0 @@
-// Copyright 2021 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build !go1.18
-// +build !go1.18
-
-package typeparams
-
-// Enabled reports whether type parameters are enabled in the current build
-// environment.
-const Enabled = false
diff --git a/vendor/golang.org/x/tools/internal/typeparams/enabled_go118.go b/vendor/golang.org/x/tools/internal/typeparams/enabled_go118.go
deleted file mode 100644
index d671488..0000000
--- a/vendor/golang.org/x/tools/internal/typeparams/enabled_go118.go
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright 2021 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build go1.18
-// +build go1.18
-
-package typeparams
-
-// Note: this constant is in a separate file as this is the only acceptable
-// diff between the <1.18 API of this package and the 1.18 API.
-
-// Enabled reports whether type parameters are enabled in the current build
-// environment.
-const Enabled = true
diff --git a/vendor/golang.org/x/tools/internal/typeparams/normalize.go b/vendor/golang.org/x/tools/internal/typeparams/normalize.go
index 090f142..93c80fd 100644
--- a/vendor/golang.org/x/tools/internal/typeparams/normalize.go
+++ b/vendor/golang.org/x/tools/internal/typeparams/normalize.go
@@ -24,20 +24,22 @@ var ErrEmptyTypeSet = errors.New("empty type set")
 // Structural type restrictions of a type parameter are created via
 // non-interface types embedded in its constraint interface (directly, or via a
 // chain of interface embeddings). For example, in the declaration
-//  type T[P interface{~int; m()}] int
+//
+//	type T[P interface{~int; m()}] int
+//
 // the structural restriction of the type parameter P is ~int.
 //
 // With interface embedding and unions, the specification of structural type
 // restrictions may be arbitrarily complex. For example, consider the
 // following:
 //
-//  type A interface{ ~string|~[]byte }
+//	type A interface{ ~string|~[]byte }
 //
-//  type B interface{ int|string }
+//	type B interface{ int|string }
 //
-//  type C interface { ~string|~int }
+//	type C interface { ~string|~int }
 //
-//  type T[P interface{ A|B; C }] int
+//	type T[P interface{ A|B; C }] int
 //
 // In this example, the structural type restriction of P is ~string|int: A|B
 // expands to ~string|~[]byte|int|string, which reduces to ~string|~[]byte|int,
@@ -58,7 +60,7 @@ var ErrEmptyTypeSet = errors.New("empty type set")
 //
 // StructuralTerms makes no guarantees about the order of terms, except that it
 // is deterministic.
-func StructuralTerms(tparam *TypeParam) ([]*Term, error) {
+func StructuralTerms(tparam *types.TypeParam) ([]*types.Term, error) {
 	constraint := tparam.Constraint()
 	if constraint == nil {
 		return nil, fmt.Errorf("%s has nil constraint", tparam)
@@ -76,7 +78,7 @@ func StructuralTerms(tparam *TypeParam) ([]*Term, error) {
 //
 // See the documentation of StructuralTerms for more information on
 // normalization.
-func InterfaceTermSet(iface *types.Interface) ([]*Term, error) {
+func InterfaceTermSet(iface *types.Interface) ([]*types.Term, error) {
 	return computeTermSet(iface)
 }
 
@@ -86,11 +88,11 @@ func InterfaceTermSet(iface *types.Interface) ([]*Term, error) {
 //
 // See the documentation of StructuralTerms for more information on
 // normalization.
-func UnionTermSet(union *Union) ([]*Term, error) {
+func UnionTermSet(union *types.Union) ([]*types.Term, error) {
 	return computeTermSet(union)
 }
 
-func computeTermSet(typ types.Type) ([]*Term, error) {
+func computeTermSet(typ types.Type) ([]*types.Term, error) {
 	tset, err := computeTermSetInternal(typ, make(map[types.Type]*termSet), 0)
 	if err != nil {
 		return nil, err
@@ -101,9 +103,9 @@ func computeTermSet(typ types.Type) ([]*Term, error) {
 	if tset.terms.isAll() {
 		return nil, nil
 	}
-	var terms []*Term
+	var terms []*types.Term
 	for _, term := range tset.terms {
-		terms = append(terms, NewTerm(term.tilde, term.typ))
+		terms = append(terms, types.NewTerm(term.tilde, term.typ))
 	}
 	return terms, nil
 }
@@ -160,7 +162,7 @@ func computeTermSetInternal(t types.Type, seen map[types.Type]*termSet, depth in
 		tset.terms = allTermlist
 		for i := 0; i < u.NumEmbeddeds(); i++ {
 			embedded := u.EmbeddedType(i)
-			if _, ok := embedded.Underlying().(*TypeParam); ok {
+			if _, ok := embedded.Underlying().(*types.TypeParam); ok {
 				return nil, fmt.Errorf("invalid embedded type %T", embedded)
 			}
 			tset2, err := computeTermSetInternal(embedded, seen, depth+1)
@@ -169,7 +171,7 @@ func computeTermSetInternal(t types.Type, seen map[types.Type]*termSet, depth in
 			}
 			tset.terms = tset.terms.intersect(tset2.terms)
 		}
-	case *Union:
+	case *types.Union:
 		// The term set of a union is the union of term sets of its terms.
 		tset.terms = nil
 		for i := 0; i < u.Len(); i++ {
@@ -182,7 +184,7 @@ func computeTermSetInternal(t types.Type, seen map[types.Type]*termSet, depth in
 					return nil, err
 				}
 				terms = tset2.terms
-			case *TypeParam, *Union:
+			case *types.TypeParam, *types.Union:
 				// A stand-alone type parameter or union is not permitted as union
 				// term.
 				return nil, fmt.Errorf("invalid union term %T", t)
@@ -197,7 +199,7 @@ func computeTermSetInternal(t types.Type, seen map[types.Type]*termSet, depth in
 				return nil, fmt.Errorf("exceeded max term count %d", maxTermCount)
 			}
 		}
-	case *TypeParam:
+	case *types.TypeParam:
 		panic("unreachable")
 	default:
 		// For all other types, the term set is just a single non-tilde term
diff --git a/vendor/golang.org/x/tools/internal/typeparams/termlist.go b/vendor/golang.org/x/tools/internal/typeparams/termlist.go
index 10857d5..cbd12f8 100644
--- a/vendor/golang.org/x/tools/internal/typeparams/termlist.go
+++ b/vendor/golang.org/x/tools/internal/typeparams/termlist.go
@@ -30,7 +30,7 @@ func (xl termlist) String() string {
 	var buf bytes.Buffer
 	for i, x := range xl {
 		if i > 0 {
-			buf.WriteString(" ∪ ")
+			buf.WriteString(" | ")
 		}
 		buf.WriteString(x.String())
 	}
@@ -97,15 +97,6 @@ func (xl termlist) norm() termlist {
 	return rl
 }
 
-// If the type set represented by xl is specified by a single (non-𝓤) term,
-// structuralType returns that type. Otherwise it returns nil.
-func (xl termlist) structuralType() types.Type {
-	if nl := xl.norm(); len(nl) == 1 {
-		return nl[0].typ // if nl.isAll() then typ is nil, which is ok
-	}
-	return nil
-}
-
 // union returns the union xl ∪ yl.
 func (xl termlist) union(yl termlist) termlist {
 	return append(xl, yl...).norm()
diff --git a/vendor/golang.org/x/tools/internal/typeparams/typeparams_go117.go b/vendor/golang.org/x/tools/internal/typeparams/typeparams_go117.go
deleted file mode 100644
index e509daf..0000000
--- a/vendor/golang.org/x/tools/internal/typeparams/typeparams_go117.go
+++ /dev/null
@@ -1,224 +0,0 @@
-// Copyright 2021 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build !go1.18
-// +build !go1.18
-
-package typeparams
-
-import (
-	"go/ast"
-	"go/token"
-	"go/types"
-)
-
-func unsupported() {
-	panic("type parameters are unsupported at this go version")
-}
-
-// GetIndexExprData extracts data from *ast.IndexExpr nodes.
-// For other nodes, GetIndexExprData returns nil.
-func GetIndexExprData(n ast.Node) *IndexExprData {
-	if e, _ := n.(*ast.IndexExpr); e != nil {
-		return &IndexExprData{
-			X:       e.X,
-			Lbrack:  e.Lbrack,
-			Indices: []ast.Expr{e.Index},
-			Rbrack:  e.Rbrack,
-		}
-	}
-	return nil
-}
-
-// PackIndexExpr returns an *ast.IndexExpr with the given index.
-// Calling PackIndexExpr with len(indices) != 1 will panic.
-func PackIndexExpr(x ast.Expr, lbrack token.Pos, indices []ast.Expr, rbrack token.Pos) ast.Expr {
-	switch len(indices) {
-	case 0:
-		panic("empty indices")
-	case 1:
-		return &ast.IndexExpr{
-			X:      x,
-			Lbrack: lbrack,
-			Index:  indices[0],
-			Rbrack: rbrack,
-		}
-	default:
-		panic("cannot pack multiple indices at this go version")
-	}
-}
-
-// IndexListExpr is a placeholder type, as type parameters are not supported at
-// this Go version. Its methods panic on use.
-type IndexListExpr struct {
-	ast.Expr
-	X       ast.Expr   // expression
-	Lbrack  token.Pos  // position of "["
-	Indices []ast.Expr // index expressions
-	Rbrack  token.Pos  // position of "]"
-}
-
-// ForTypeSpec returns an empty field list, as type parameters on not supported
-// at this Go version.
-func ForTypeSpec(*ast.TypeSpec) *ast.FieldList {
-	return nil
-}
-
-// ForFuncType returns an empty field list, as type parameters are not
-// supported at this Go version.
-func ForFuncType(*ast.FuncType) *ast.FieldList {
-	return nil
-}
-
-// TypeParam is a placeholder type, as type parameters are not supported at
-// this Go version. Its methods panic on use.
-type TypeParam struct{ types.Type }
-
-func (*TypeParam) Index() int             { unsupported(); return 0 }
-func (*TypeParam) Constraint() types.Type { unsupported(); return nil }
-func (*TypeParam) Obj() *types.TypeName   { unsupported(); return nil }
-
-// TypeParamList is a placeholder for an empty type parameter list.
-type TypeParamList struct{}
-
-func (*TypeParamList) Len() int          { return 0 }
-func (*TypeParamList) At(int) *TypeParam { unsupported(); return nil }
-
-// TypeList is a placeholder for an empty type list.
-type TypeList struct{}
-
-func (*TypeList) Len() int          { return 0 }
-func (*TypeList) At(int) types.Type { unsupported(); return nil }
-
-// NewTypeParam is unsupported at this Go version, and panics.
-func NewTypeParam(name *types.TypeName, constraint types.Type) *TypeParam {
-	unsupported()
-	return nil
-}
-
-// SetTypeParamConstraint is unsupported at this Go version, and panics.
-func SetTypeParamConstraint(tparam *TypeParam, constraint types.Type) {
-	unsupported()
-}
-
-// NewSignatureType calls types.NewSignature, panicking if recvTypeParams or
-// typeParams is non-empty.
-func NewSignatureType(recv *types.Var, recvTypeParams, typeParams []*TypeParam, params, results *types.Tuple, variadic bool) *types.Signature {
-	if len(recvTypeParams) != 0 || len(typeParams) != 0 {
-		panic("signatures cannot have type parameters at this Go version")
-	}
-	return types.NewSignature(recv, params, results, variadic)
-}
-
-// ForSignature returns an empty slice.
-func ForSignature(*types.Signature) *TypeParamList {
-	return nil
-}
-
-// RecvTypeParams returns a nil slice.
-func RecvTypeParams(sig *types.Signature) *TypeParamList {
-	return nil
-}
-
-// IsComparable returns false, as no interfaces are type-restricted at this Go
-// version.
-func IsComparable(*types.Interface) bool {
-	return false
-}
-
-// IsMethodSet returns true, as no interfaces are type-restricted at this Go
-// version.
-func IsMethodSet(*types.Interface) bool {
-	return true
-}
-
-// IsImplicit returns false, as no interfaces are implicit at this Go version.
-func IsImplicit(*types.Interface) bool {
-	return false
-}
-
-// MarkImplicit does nothing, because this Go version does not have implicit
-// interfaces.
-func MarkImplicit(*types.Interface) {}
-
-// ForNamed returns an empty type parameter list, as type parameters are not
-// supported at this Go version.
-func ForNamed(*types.Named) *TypeParamList {
-	return nil
-}
-
-// SetForNamed panics if tparams is non-empty.
-func SetForNamed(_ *types.Named, tparams []*TypeParam) {
-	if len(tparams) > 0 {
-		unsupported()
-	}
-}
-
-// NamedTypeArgs returns nil.
-func NamedTypeArgs(*types.Named) *TypeList {
-	return nil
-}
-
-// NamedTypeOrigin is the identity method at this Go version.
-func NamedTypeOrigin(named *types.Named) types.Type {
-	return named
-}
-
-// Term holds information about a structural type restriction.
-type Term struct {
-	tilde bool
-	typ   types.Type
-}
-
-func (m *Term) Tilde() bool      { return m.tilde }
-func (m *Term) Type() types.Type { return m.typ }
-func (m *Term) String() string {
-	pre := ""
-	if m.tilde {
-		pre = "~"
-	}
-	return pre + m.typ.String()
-}
-
-// NewTerm is unsupported at this Go version, and panics.
-func NewTerm(tilde bool, typ types.Type) *Term {
-	return &Term{tilde, typ}
-}
-
-// Union is a placeholder type, as type parameters are not supported at this Go
-// version. Its methods panic on use.
-type Union struct{ types.Type }
-
-func (*Union) Len() int         { return 0 }
-func (*Union) Term(i int) *Term { unsupported(); return nil }
-
-// NewUnion is unsupported at this Go version, and panics.
-func NewUnion(terms []*Term) *Union {
-	unsupported()
-	return nil
-}
-
-// InitInstanceInfo is a noop at this Go version.
-func InitInstanceInfo(*types.Info) {}
-
-// Instance is a placeholder type, as type parameters are not supported at this
-// Go version.
-type Instance struct {
-	TypeArgs *TypeList
-	Type     types.Type
-}
-
-// GetInstances returns a nil map, as type parameters are not supported at this
-// Go version.
-func GetInstances(info *types.Info) map[*ast.Ident]Instance { return nil }
-
-// Context is a placeholder type, as type parameters are not supported at
-// this Go version.
-type Context struct{}
-
-// Instantiate is unsupported on this Go version, and panics.
-func Instantiate(ctxt *Context, typ types.Type, targs []types.Type, validate bool) (types.Type, error) {
-	unsupported()
-	return nil, nil
-}
diff --git a/vendor/golang.org/x/tools/internal/typeparams/typeparams_go118.go b/vendor/golang.org/x/tools/internal/typeparams/typeparams_go118.go
deleted file mode 100644
index e45896f..0000000
--- a/vendor/golang.org/x/tools/internal/typeparams/typeparams_go118.go
+++ /dev/null
@@ -1,196 +0,0 @@
-// Copyright 2021 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build go1.18
-// +build go1.18
-
-package typeparams
-
-import (
-	"go/ast"
-	"go/token"
-	"go/types"
-)
-
-// GetIndexExprData extracts data from AST nodes that represent index
-// expressions.
-//
-// For an ast.IndexExpr, the resulting IndexExprData will have exactly one
-// index expression. For an ast.IndexListExpr (go1.18+), it may have a
-// variable number of index expressions.
-//
-// For nodes that don't represent index expressions, GetIndexExprData returns
-// nil.
-// TODO(rfindley): remove this function in favor of using the alias below.
-func GetIndexExprData(n ast.Node) *IndexExprData {
-	switch e := n.(type) {
-	case *ast.IndexExpr:
-		return &IndexExprData{
-			X:       e.X,
-			Lbrack:  e.Lbrack,
-			Indices: []ast.Expr{e.Index},
-			Rbrack:  e.Rbrack,
-		}
-	case *ast.IndexListExpr:
-		return (*IndexExprData)(e)
-	}
-	return nil
-}
-
-// PackIndexExpr returns an *ast.IndexExpr or *ast.IndexListExpr, depending on
-// the cardinality of indices. Calling PackIndexExpr with len(indices) == 0
-// will panic.
-func PackIndexExpr(x ast.Expr, lbrack token.Pos, indices []ast.Expr, rbrack token.Pos) ast.Expr {
-	switch len(indices) {
-	case 0:
-		panic("empty indices")
-	case 1:
-		return &ast.IndexExpr{
-			X:      x,
-			Lbrack: lbrack,
-			Index:  indices[0],
-			Rbrack: rbrack,
-		}
-	default:
-		return &ast.IndexListExpr{
-			X:       x,
-			Lbrack:  lbrack,
-			Indices: indices,
-			Rbrack:  rbrack,
-		}
-	}
-}
-
-// IndexListExpr is an alias for ast.IndexListExpr.
-type IndexListExpr = ast.IndexListExpr
-
-// ForTypeSpec returns n.TypeParams.
-func ForTypeSpec(n *ast.TypeSpec) *ast.FieldList {
-	if n == nil {
-		return nil
-	}
-	return n.TypeParams
-}
-
-// ForFuncType returns n.TypeParams.
-func ForFuncType(n *ast.FuncType) *ast.FieldList {
-	if n == nil {
-		return nil
-	}
-	return n.TypeParams
-}
-
-// TypeParam is an alias for types.TypeParam
-type TypeParam = types.TypeParam
-
-// TypeParamList is an alias for types.TypeParamList
-type TypeParamList = types.TypeParamList
-
-// TypeList is an alias for types.TypeList
-type TypeList = types.TypeList
-
-// NewTypeParam calls types.NewTypeParam.
-func NewTypeParam(name *types.TypeName, constraint types.Type) *TypeParam {
-	return types.NewTypeParam(name, constraint)
-}
-
-// SetTypeParamConstraint calls tparam.SetConstraint(constraint).
-func SetTypeParamConstraint(tparam *TypeParam, constraint types.Type) {
-	tparam.SetConstraint(constraint)
-}
-
-// NewSignatureType calls types.NewSignatureType.
-func NewSignatureType(recv *types.Var, recvTypeParams, typeParams []*TypeParam, params, results *types.Tuple, variadic bool) *types.Signature {
-	return types.NewSignatureType(recv, recvTypeParams, typeParams, params, results, variadic)
-}
-
-// ForSignature returns sig.TypeParams()
-func ForSignature(sig *types.Signature) *TypeParamList {
-	return sig.TypeParams()
-}
-
-// RecvTypeParams returns sig.RecvTypeParams().
-func RecvTypeParams(sig *types.Signature) *TypeParamList {
-	return sig.RecvTypeParams()
-}
-
-// IsComparable calls iface.IsComparable().
-func IsComparable(iface *types.Interface) bool {
-	return iface.IsComparable()
-}
-
-// IsMethodSet calls iface.IsMethodSet().
-func IsMethodSet(iface *types.Interface) bool {
-	return iface.IsMethodSet()
-}
-
-// IsImplicit calls iface.IsImplicit().
-func IsImplicit(iface *types.Interface) bool {
-	return iface.IsImplicit()
-}
-
-// MarkImplicit calls iface.MarkImplicit().
-func MarkImplicit(iface *types.Interface) {
-	iface.MarkImplicit()
-}
-
-// ForNamed extracts the (possibly empty) type parameter object list from
-// named.
-func ForNamed(named *types.Named) *TypeParamList {
-	return named.TypeParams()
-}
-
-// SetForNamed sets the type params tparams on n. Each tparam must be of
-// dynamic type *types.TypeParam.
-func SetForNamed(n *types.Named, tparams []*TypeParam) {
-	n.SetTypeParams(tparams)
-}
-
-// NamedTypeArgs returns named.TypeArgs().
-func NamedTypeArgs(named *types.Named) *TypeList {
-	return named.TypeArgs()
-}
-
-// NamedTypeOrigin returns named.Orig().
-func NamedTypeOrigin(named *types.Named) types.Type {
-	return named.Origin()
-}
-
-// Term is an alias for types.Term.
-type Term = types.Term
-
-// NewTerm calls types.NewTerm.
-func NewTerm(tilde bool, typ types.Type) *Term {
-	return types.NewTerm(tilde, typ)
-}
-
-// Union is an alias for types.Union
-type Union = types.Union
-
-// NewUnion calls types.NewUnion.
-func NewUnion(terms []*Term) *Union {
-	return types.NewUnion(terms)
-}
-
-// InitInstanceInfo initializes info to record information about type and
-// function instances.
-func InitInstanceInfo(info *types.Info) {
-	info.Instances = make(map[*ast.Ident]types.Instance)
-}
-
-// Instance is an alias for types.Instance.
-type Instance = types.Instance
-
-// GetInstances returns info.Instances.
-func GetInstances(info *types.Info) map[*ast.Ident]Instance {
-	return info.Instances
-}
-
-// Context is an alias for types.Context.
-type Context = types.Context
-
-// Instantiate calls types.Instantiate.
-func Instantiate(ctxt *Context, typ types.Type, targs []types.Type, validate bool) (types.Type, error) {
-	return types.Instantiate(ctxt, typ, targs, validate)
-}
diff --git a/vendor/golang.org/x/tools/internal/typeparams/typeterm.go b/vendor/golang.org/x/tools/internal/typeparams/typeterm.go
index 7ddee28..7350bb7 100644
--- a/vendor/golang.org/x/tools/internal/typeparams/typeterm.go
+++ b/vendor/golang.org/x/tools/internal/typeparams/typeterm.go
@@ -10,11 +10,10 @@ import "go/types"
 
 // A term describes elementary type sets:
 //
-//   ∅:  (*term)(nil)     == ∅                      // set of no types (empty set)
-//   𝓤:  &term{}          == 𝓤                      // set of all types (𝓤niverse)
-//   T:  &term{false, T}  == {T}                    // set of type T
-//  ~t:  &term{true, t}   == {t' | under(t') == t}  // set of types with underlying type t
-//
+//	 ∅:  (*term)(nil)     == ∅                      // set of no types (empty set)
+//	 𝓤:  &term{}          == 𝓤                      // set of all types (𝓤niverse)
+//	 T:  &term{false, T}  == {T}                    // set of type T
+//	~t:  &term{true, t}   == {t' | under(t') == t}  // set of types with underlying type t
 type term struct {
 	tilde bool // valid if typ != nil
 	typ   types.Type
diff --git a/vendor/golang.org/x/tools/internal/typesinternal/errorcode.go b/vendor/golang.org/x/tools/internal/typesinternal/errorcode.go
index fa2834e..0748407 100644
--- a/vendor/golang.org/x/tools/internal/typesinternal/errorcode.go
+++ b/vendor/golang.org/x/tools/internal/typesinternal/errorcode.go
@@ -30,6 +30,12 @@ type ErrorCode int
 // convention that "bad" implies a problem with syntax, and "invalid" implies a
 // problem with types.
 
+const (
+	// InvalidSyntaxTree occurs if an invalid syntax tree is provided
+	// to the type checker. It should never happen.
+	InvalidSyntaxTree ErrorCode = -1
+)
+
 const (
 	_ ErrorCode = iota
 
@@ -153,12 +159,12 @@ const (
 
 	/* decls > var (+ other variable assignment codes) */
 
-	// UntypedNil occurs when the predeclared (untyped) value nil is used to
+	// UntypedNilUse occurs when the predeclared (untyped) value nil is used to
 	// initialize a variable declared without an explicit type.
 	//
 	// Example:
 	//  var x = nil
-	UntypedNil
+	UntypedNilUse
 
 	// WrongAssignCount occurs when the number of values on the right-hand side
 	// of an assignment or or initialization expression does not match the number
@@ -1365,4 +1371,190 @@ const (
 	//  	return i
 	//  }
 	InvalidGo
+
+	// All codes below were added in Go 1.17.
+
+	/* decl */
+
+	// BadDecl occurs when a declaration has invalid syntax.
+	BadDecl
+
+	// RepeatedDecl occurs when an identifier occurs more than once on the left
+	// hand side of a short variable declaration.
+	//
+	// Example:
+	//  func _() {
+	//  	x, y, y := 1, 2, 3
+	//  }
+	RepeatedDecl
+
+	/* unsafe */
+
+	// InvalidUnsafeAdd occurs when unsafe.Add is called with a
+	// length argument that is not of integer type.
+	//
+	// Example:
+	//  import "unsafe"
+	//
+	//  var p unsafe.Pointer
+	//  var _ = unsafe.Add(p, float64(1))
+	InvalidUnsafeAdd
+
+	// InvalidUnsafeSlice occurs when unsafe.Slice is called with a
+	// pointer argument that is not of pointer type or a length argument
+	// that is not of integer type, negative, or out of bounds.
+	//
+	// Example:
+	//  import "unsafe"
+	//
+	//  var x int
+	//  var _ = unsafe.Slice(x, 1)
+	//
+	// Example:
+	//  import "unsafe"
+	//
+	//  var x int
+	//  var _ = unsafe.Slice(&x, float64(1))
+	//
+	// Example:
+	//  import "unsafe"
+	//
+	//  var x int
+	//  var _ = unsafe.Slice(&x, -1)
+	//
+	// Example:
+	//  import "unsafe"
+	//
+	//  var x int
+	//  var _ = unsafe.Slice(&x, uint64(1) << 63)
+	InvalidUnsafeSlice
+
+	// All codes below were added in Go 1.18.
+
+	/* features */
+
+	// UnsupportedFeature occurs when a language feature is used that is not
+	// supported at this Go version.
+	UnsupportedFeature
+
+	/* type params */
+
+	// NotAGenericType occurs when a non-generic type is used where a generic
+	// type is expected: in type or function instantiation.
+	//
+	// Example:
+	//  type T int
+	//
+	//  var _ T[int]
+	NotAGenericType
+
+	// WrongTypeArgCount occurs when a type or function is instantiated with an
+	// incorrent number of type arguments, including when a generic type or
+	// function is used without instantiation.
+	//
+	// Errors inolving failed type inference are assigned other error codes.
+	//
+	// Example:
+	//  type T[p any] int
+	//
+	//  var _ T[int, string]
+	//
+	// Example:
+	//  func f[T any]() {}
+	//
+	//  var x = f
+	WrongTypeArgCount
+
+	// CannotInferTypeArgs occurs when type or function type argument inference
+	// fails to infer all type arguments.
+	//
+	// Example:
+	//  func f[T any]() {}
+	//
+	//  func _() {
+	//  	f()
+	//  }
+	//
+	// Example:
+	//   type N[P, Q any] struct{}
+	//
+	//   var _ N[int]
+	CannotInferTypeArgs
+
+	// InvalidTypeArg occurs when a type argument does not satisfy its
+	// corresponding type parameter constraints.
+	//
+	// Example:
+	//  type T[P ~int] struct{}
+	//
+	//  var _ T[string]
+	InvalidTypeArg // arguments? InferenceFailed
+
+	// InvalidInstanceCycle occurs when an invalid cycle is detected
+	// within the instantiation graph.
+	//
+	// Example:
+	//  func f[T any]() { f[*T]() }
+	InvalidInstanceCycle
+
+	// InvalidUnion occurs when an embedded union or approximation element is
+	// not valid.
+	//
+	// Example:
+	//  type _ interface {
+	//   	~int | interface{ m() }
+	//  }
+	InvalidUnion
+
+	// MisplacedConstraintIface occurs when a constraint-type interface is used
+	// outside of constraint position.
+	//
+	// Example:
+	//   type I interface { ~int }
+	//
+	//   var _ I
+	MisplacedConstraintIface
+
+	// InvalidMethodTypeParams occurs when methods have type parameters.
+	//
+	// It cannot be encountered with an AST parsed using go/parser.
+	InvalidMethodTypeParams
+
+	// MisplacedTypeParam occurs when a type parameter is used in a place where
+	// it is not permitted.
+	//
+	// Example:
+	//  type T[P any] P
+	//
+	// Example:
+	//  type T[P any] struct{ *P }
+	MisplacedTypeParam
+
+	// InvalidUnsafeSliceData occurs when unsafe.SliceData is called with
+	// an argument that is not of slice type. It also occurs if it is used
+	// in a package compiled for a language version before go1.20.
+	//
+	// Example:
+	//  import "unsafe"
+	//
+	//  var x int
+	//  var _ = unsafe.SliceData(x)
+	InvalidUnsafeSliceData
+
+	// InvalidUnsafeString occurs when unsafe.String is called with
+	// a length argument that is not of integer type, negative, or
+	// out of bounds. It also occurs if it is used in a package
+	// compiled for a language version before go1.20.
+	//
+	// Example:
+	//  import "unsafe"
+	//
+	//  var b [10]byte
+	//  var _ = unsafe.String(&b[0], -1)
+	InvalidUnsafeString
+
+	// InvalidUnsafeStringData occurs if it is used in a package
+	// compiled for a language version before go1.20.
+	_ // not used anymore
+
 )
diff --git a/vendor/golang.org/x/tools/internal/typesinternal/errorcode_string.go b/vendor/golang.org/x/tools/internal/typesinternal/errorcode_string.go
index 3e5842a..15ecf7c 100644
--- a/vendor/golang.org/x/tools/internal/typesinternal/errorcode_string.go
+++ b/vendor/golang.org/x/tools/internal/typesinternal/errorcode_string.go
@@ -8,6 +8,7 @@ func _() {
 	// An "invalid array index" compiler error signifies that the constant values have changed.
 	// Re-run the stringer command to generate them again.
 	var x [1]struct{}
+	_ = x[InvalidSyntaxTree - -1]
 	_ = x[Test-1]
 	_ = x[BlankPkgName-2]
 	_ = x[MismatchedPkgName-3]
@@ -23,7 +24,7 @@ func _() {
 	_ = x[InvalidConstInit-13]
 	_ = x[InvalidConstVal-14]
 	_ = x[InvalidConstType-15]
-	_ = x[UntypedNil-16]
+	_ = x[UntypedNilUse-16]
 	_ = x[WrongAssignCount-17]
 	_ = x[UnassignableOperand-18]
 	_ = x[NoNewVar-19]
@@ -138,16 +139,41 @@ func _() {
 	_ = x[UnusedResults-128]
 	_ = x[InvalidDefer-129]
 	_ = x[InvalidGo-130]
+	_ = x[BadDecl-131]
+	_ = x[RepeatedDecl-132]
+	_ = x[InvalidUnsafeAdd-133]
+	_ = x[InvalidUnsafeSlice-134]
+	_ = x[UnsupportedFeature-135]
+	_ = x[NotAGenericType-136]
+	_ = x[WrongTypeArgCount-137]
+	_ = x[CannotInferTypeArgs-138]
+	_ = x[InvalidTypeArg-139]
+	_ = x[InvalidInstanceCycle-140]
+	_ = x[InvalidUnion-141]
+	_ = x[MisplacedConstraintIface-142]
+	_ = x[InvalidMethodTypeParams-143]
+	_ = x[MisplacedTypeParam-144]
+	_ = x[InvalidUnsafeSliceData-145]
+	_ = x[InvalidUnsafeString-146]
 }
 
-const _ErrorCode_name = "TestBlankPkgNameMismatchedPkgNameInvalidPkgUseBadImportPathBrokenImportImportCRenamedUnusedImportInvalidInitCycleDuplicateDeclInvalidDeclCycleInvalidTypeCycleInvalidConstInitInvalidConstValInvalidConstTypeUntypedNilWrongAssignCountUnassignableOperandNoNewVarMultiValAssignOpInvalidIfaceAssignInvalidChanAssignIncompatibleAssignUnaddressableFieldAssignNotATypeInvalidArrayLenBlankIfaceMethodIncomparableMapKeyInvalidIfaceEmbedInvalidPtrEmbedBadRecvInvalidRecvDuplicateFieldAndMethodDuplicateMethodInvalidBlankInvalidIotaMissingInitBodyInvalidInitSigInvalidInitDeclInvalidMainDeclTooManyValuesNotAnExprTruncatedFloatNumericOverflowUndefinedOpMismatchedTypesDivByZeroNonNumericIncDecUnaddressableOperandInvalidIndirectionNonIndexableOperandInvalidIndexSwappedSliceIndicesNonSliceableOperandInvalidSliceExprInvalidShiftCountInvalidShiftOperandInvalidReceiveInvalidSendDuplicateLitKeyMissingLitKeyInvalidLitIndexOversizeArrayLitMixedStructLitInvalidStructLitMissingLitFieldDuplicateLitFieldUnexportedLitFieldInvalidLitFieldUntypedLitInvalidLitAmbiguousSelectorUndeclaredImportedNameUnexportedNameUndeclaredNameMissingFieldOrMethodBadDotDotDotSyntaxNonVariadicDotDotDotMisplacedDotDotDotInvalidDotDotDotOperandInvalidDotDotDotUncalledBuiltinInvalidAppendInvalidCapInvalidCloseInvalidCopyInvalidComplexInvalidDeleteInvalidImagInvalidLenSwappedMakeArgsInvalidMakeInvalidRealInvalidAssertImpossibleAssertInvalidConversionInvalidUntypedConversionBadOffsetofSyntaxInvalidOffsetofUnusedExprUnusedVarMissingReturnWrongResultCountOutOfScopeResultInvalidCondInvalidPostDeclInvalidChanRangeInvalidIterVarInvalidRangeExprMisplacedBreakMisplacedContinueMisplacedFallthroughDuplicateCaseDuplicateDefaultBadTypeKeywordInvalidTypeSwitchInvalidExprSwitchInvalidSelectCaseUndeclaredLabelDuplicateLabelMisplacedLabelUnusedLabelJumpOverDeclJumpIntoBlockInvalidMethodExprWrongArgCountInvalidCallUnusedResultsInvalidDeferInvalidGo"
+const (
+	_ErrorCode_name_0 = "InvalidSyntaxTree"
+	_ErrorCode_name_1 = "TestBlankPkgNameMismatchedPkgNameInvalidPkgUseBadImportPathBrokenImportImportCRenamedUnusedImportInvalidInitCycleDuplicateDeclInvalidDeclCycleInvalidTypeCycleInvalidConstInitInvalidConstValInvalidConstTypeUntypedNilUseWrongAssignCountUnassignableOperandNoNewVarMultiValAssignOpInvalidIfaceAssignInvalidChanAssignIncompatibleAssignUnaddressableFieldAssignNotATypeInvalidArrayLenBlankIfaceMethodIncomparableMapKeyInvalidIfaceEmbedInvalidPtrEmbedBadRecvInvalidRecvDuplicateFieldAndMethodDuplicateMethodInvalidBlankInvalidIotaMissingInitBodyInvalidInitSigInvalidInitDeclInvalidMainDeclTooManyValuesNotAnExprTruncatedFloatNumericOverflowUndefinedOpMismatchedTypesDivByZeroNonNumericIncDecUnaddressableOperandInvalidIndirectionNonIndexableOperandInvalidIndexSwappedSliceIndicesNonSliceableOperandInvalidSliceExprInvalidShiftCountInvalidShiftOperandInvalidReceiveInvalidSendDuplicateLitKeyMissingLitKeyInvalidLitIndexOversizeArrayLitMixedStructLitInvalidStructLitMissingLitFieldDuplicateLitFieldUnexportedLitFieldInvalidLitFieldUntypedLitInvalidLitAmbiguousSelectorUndeclaredImportedNameUnexportedNameUndeclaredNameMissingFieldOrMethodBadDotDotDotSyntaxNonVariadicDotDotDotMisplacedDotDotDotInvalidDotDotDotOperandInvalidDotDotDotUncalledBuiltinInvalidAppendInvalidCapInvalidCloseInvalidCopyInvalidComplexInvalidDeleteInvalidImagInvalidLenSwappedMakeArgsInvalidMakeInvalidRealInvalidAssertImpossibleAssertInvalidConversionInvalidUntypedConversionBadOffsetofSyntaxInvalidOffsetofUnusedExprUnusedVarMissingReturnWrongResultCountOutOfScopeResultInvalidCondInvalidPostDeclInvalidChanRangeInvalidIterVarInvalidRangeExprMisplacedBreakMisplacedContinueMisplacedFallthroughDuplicateCaseDuplicateDefaultBadTypeKeywordInvalidTypeSwitchInvalidExprSwitchInvalidSelectCaseUndeclaredLabelDuplicateLabelMisplacedLabelUnusedLabelJumpOverDeclJumpIntoBlockInvalidMethodExprWrongArgCountInvalidCallUnusedResultsInvalidDeferInvalidGoBadDeclRepeatedDeclInvalidUnsafeAddInvalidUnsafeSliceUnsupportedFeatureNotAGenericTypeWrongTypeArgCountCannotInferTypeArgsInvalidTypeArgInvalidInstanceCycleInvalidUnionMisplacedConstraintIfaceInvalidMethodTypeParamsMisplacedTypeParamInvalidUnsafeSliceDataInvalidUnsafeString"
+)
 
-var _ErrorCode_index = [...]uint16{0, 4, 16, 33, 46, 59, 71, 85, 97, 113, 126, 142, 158, 174, 189, 205, 215, 231, 250, 258, 274, 292, 309, 327, 351, 359, 374, 390, 408, 425, 440, 447, 458, 481, 496, 508, 519, 534, 548, 563, 578, 591, 600, 614, 629, 640, 655, 664, 680, 700, 718, 737, 749, 768, 787, 803, 820, 839, 853, 864, 879, 892, 907, 923, 937, 953, 968, 985, 1003, 1018, 1028, 1038, 1055, 1077, 1091, 1105, 1125, 1143, 1163, 1181, 1204, 1220, 1235, 1248, 1258, 1270, 1281, 1295, 1308, 1319, 1329, 1344, 1355, 1366, 1379, 1395, 1412, 1436, 1453, 1468, 1478, 1487, 1500, 1516, 1532, 1543, 1558, 1574, 1588, 1604, 1618, 1635, 1655, 1668, 1684, 1698, 1715, 1732, 1749, 1764, 1778, 1792, 1803, 1815, 1828, 1845, 1858, 1869, 1882, 1894, 1903}
+var (
+	_ErrorCode_index_1 = [...]uint16{0, 4, 16, 33, 46, 59, 71, 85, 97, 113, 126, 142, 158, 174, 189, 205, 218, 234, 253, 261, 277, 295, 312, 330, 354, 362, 377, 393, 411, 428, 443, 450, 461, 484, 499, 511, 522, 537, 551, 566, 581, 594, 603, 617, 632, 643, 658, 667, 683, 703, 721, 740, 752, 771, 790, 806, 823, 842, 856, 867, 882, 895, 910, 926, 940, 956, 971, 988, 1006, 1021, 1031, 1041, 1058, 1080, 1094, 1108, 1128, 1146, 1166, 1184, 1207, 1223, 1238, 1251, 1261, 1273, 1284, 1298, 1311, 1322, 1332, 1347, 1358, 1369, 1382, 1398, 1415, 1439, 1456, 1471, 1481, 1490, 1503, 1519, 1535, 1546, 1561, 1577, 1591, 1607, 1621, 1638, 1658, 1671, 1687, 1701, 1718, 1735, 1752, 1767, 1781, 1795, 1806, 1818, 1831, 1848, 1861, 1872, 1885, 1897, 1906, 1913, 1925, 1941, 1959, 1977, 1992, 2009, 2028, 2042, 2062, 2074, 2098, 2121, 2139, 2161, 2180}
+)
 
 func (i ErrorCode) String() string {
-	i -= 1
-	if i < 0 || i >= ErrorCode(len(_ErrorCode_index)-1) {
-		return "ErrorCode(" + strconv.FormatInt(int64(i+1), 10) + ")"
+	switch {
+	case i == -1:
+		return _ErrorCode_name_0
+	case 1 <= i && i <= 146:
+		i -= 1
+		return _ErrorCode_name_1[_ErrorCode_index_1[i]:_ErrorCode_index_1[i+1]]
+	default:
+		return "ErrorCode(" + strconv.FormatInt(int64(i), 10) + ")"
 	}
-	return _ErrorCode_name[_ErrorCode_index[i]:_ErrorCode_index[i+1]]
 }
diff --git a/vendor/golang.org/x/tools/internal/typesinternal/types.go b/vendor/golang.org/x/tools/internal/typesinternal/types.go
index 7c77c2f..ce7d435 100644
--- a/vendor/golang.org/x/tools/internal/typesinternal/types.go
+++ b/vendor/golang.org/x/tools/internal/typesinternal/types.go
@@ -48,3 +48,5 @@ func ReadGo116ErrorData(err types.Error) (code ErrorCode, start, end token.Pos,
 	}
 	return ErrorCode(data[0]), token.Pos(data[1]), token.Pos(data[2]), true
 }
+
+var SetGoVersion = func(conf *types.Config, version string) bool { return false }
diff --git a/vendor/golang.org/x/xerrors/LICENSE b/vendor/golang.org/x/xerrors/LICENSE
deleted file mode 100644
index e4a47e1..0000000
--- a/vendor/golang.org/x/xerrors/LICENSE
+++ /dev/null
@@ -1,27 +0,0 @@
-Copyright (c) 2019 The Go Authors. All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/golang.org/x/xerrors/PATENTS b/vendor/golang.org/x/xerrors/PATENTS
deleted file mode 100644
index 7330990..0000000
--- a/vendor/golang.org/x/xerrors/PATENTS
+++ /dev/null
@@ -1,22 +0,0 @@
-Additional IP Rights Grant (Patents)
-
-"This implementation" means the copyrightable works distributed by
-Google as part of the Go project.
-
-Google hereby grants to You a perpetual, worldwide, non-exclusive,
-no-charge, royalty-free, irrevocable (except as stated in this section)
-patent license to make, have made, use, offer to sell, sell, import,
-transfer and otherwise run, modify and propagate the contents of this
-implementation of Go, where such license applies only to those patent
-claims, both currently owned or controlled by Google and acquired in
-the future, licensable by Google that are necessarily infringed by this
-implementation of Go.  This grant does not include claims that would be
-infringed only as a consequence of further modification of this
-implementation.  If you or your agent or exclusive licensee institute or
-order or agree to the institution of patent litigation against any
-entity (including a cross-claim or counterclaim in a lawsuit) alleging
-that this implementation of Go or any code incorporated within this
-implementation of Go constitutes direct or contributory patent
-infringement, or inducement of patent infringement, then any patent
-rights granted to you under this License for this implementation of Go
-shall terminate as of the date such litigation is filed.
diff --git a/vendor/golang.org/x/xerrors/README b/vendor/golang.org/x/xerrors/README
deleted file mode 100644
index aac7867..0000000
--- a/vendor/golang.org/x/xerrors/README
+++ /dev/null
@@ -1,2 +0,0 @@
-This repository holds the transition packages for the new Go 1.13 error values.
-See golang.org/design/29934-error-values.
diff --git a/vendor/golang.org/x/xerrors/adaptor.go b/vendor/golang.org/x/xerrors/adaptor.go
deleted file mode 100644
index 4317f24..0000000
--- a/vendor/golang.org/x/xerrors/adaptor.go
+++ /dev/null
@@ -1,193 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package xerrors
-
-import (
-	"bytes"
-	"fmt"
-	"io"
-	"reflect"
-	"strconv"
-)
-
-// FormatError calls the FormatError method of f with an errors.Printer
-// configured according to s and verb, and writes the result to s.
-func FormatError(f Formatter, s fmt.State, verb rune) {
-	// Assuming this function is only called from the Format method, and given
-	// that FormatError takes precedence over Format, it cannot be called from
-	// any package that supports errors.Formatter. It is therefore safe to
-	// disregard that State may be a specific printer implementation and use one
-	// of our choice instead.
-
-	// limitations: does not support printing error as Go struct.
-
-	var (
-		sep    = " " // separator before next error
-		p      = &state{State: s}
-		direct = true
-	)
-
-	var err error = f
-
-	switch verb {
-	// Note that this switch must match the preference order
-	// for ordinary string printing (%#v before %+v, and so on).
-
-	case 'v':
-		if s.Flag('#') {
-			if stringer, ok := err.(fmt.GoStringer); ok {
-				io.WriteString(&p.buf, stringer.GoString())
-				goto exit
-			}
-			// proceed as if it were %v
-		} else if s.Flag('+') {
-			p.printDetail = true
-			sep = "\n  - "
-		}
-	case 's':
-	case 'q', 'x', 'X':
-		// Use an intermediate buffer in the rare cases that precision,
-		// truncation, or one of the alternative verbs (q, x, and X) are
-		// specified.
-		direct = false
-
-	default:
-		p.buf.WriteString("%!")
-		p.buf.WriteRune(verb)
-		p.buf.WriteByte('(')
-		switch {
-		case err != nil:
-			p.buf.WriteString(reflect.TypeOf(f).String())
-		default:
-			p.buf.WriteString("<nil>")
-		}
-		p.buf.WriteByte(')')
-		io.Copy(s, &p.buf)
-		return
-	}
-
-loop:
-	for {
-		switch v := err.(type) {
-		case Formatter:
-			err = v.FormatError((*printer)(p))
-		case fmt.Formatter:
-			v.Format(p, 'v')
-			break loop
-		default:
-			io.WriteString(&p.buf, v.Error())
-			break loop
-		}
-		if err == nil {
-			break
-		}
-		if p.needColon || !p.printDetail {
-			p.buf.WriteByte(':')
-			p.needColon = false
-		}
-		p.buf.WriteString(sep)
-		p.inDetail = false
-		p.needNewline = false
-	}
-
-exit:
-	width, okW := s.Width()
-	prec, okP := s.Precision()
-
-	if !direct || (okW && width > 0) || okP {
-		// Construct format string from State s.
-		format := []byte{'%'}
-		if s.Flag('-') {
-			format = append(format, '-')
-		}
-		if s.Flag('+') {
-			format = append(format, '+')
-		}
-		if s.Flag(' ') {
-			format = append(format, ' ')
-		}
-		if okW {
-			format = strconv.AppendInt(format, int64(width), 10)
-		}
-		if okP {
-			format = append(format, '.')
-			format = strconv.AppendInt(format, int64(prec), 10)
-		}
-		format = append(format, string(verb)...)
-		fmt.Fprintf(s, string(format), p.buf.String())
-	} else {
-		io.Copy(s, &p.buf)
-	}
-}
-
-var detailSep = []byte("\n    ")
-
-// state tracks error printing state. It implements fmt.State.
-type state struct {
-	fmt.State
-	buf bytes.Buffer
-
-	printDetail bool
-	inDetail    bool
-	needColon   bool
-	needNewline bool
-}
-
-func (s *state) Write(b []byte) (n int, err error) {
-	if s.printDetail {
-		if len(b) == 0 {
-			return 0, nil
-		}
-		if s.inDetail && s.needColon {
-			s.needNewline = true
-			if b[0] == '\n' {
-				b = b[1:]
-			}
-		}
-		k := 0
-		for i, c := range b {
-			if s.needNewline {
-				if s.inDetail && s.needColon {
-					s.buf.WriteByte(':')
-					s.needColon = false
-				}
-				s.buf.Write(detailSep)
-				s.needNewline = false
-			}
-			if c == '\n' {
-				s.buf.Write(b[k:i])
-				k = i + 1
-				s.needNewline = true
-			}
-		}
-		s.buf.Write(b[k:])
-		if !s.inDetail {
-			s.needColon = true
-		}
-	} else if !s.inDetail {
-		s.buf.Write(b)
-	}
-	return len(b), nil
-}
-
-// printer wraps a state to implement an xerrors.Printer.
-type printer state
-
-func (s *printer) Print(args ...interface{}) {
-	if !s.inDetail || s.printDetail {
-		fmt.Fprint((*state)(s), args...)
-	}
-}
-
-func (s *printer) Printf(format string, args ...interface{}) {
-	if !s.inDetail || s.printDetail {
-		fmt.Fprintf((*state)(s), format, args...)
-	}
-}
-
-func (s *printer) Detail() bool {
-	s.inDetail = true
-	return s.printDetail
-}
diff --git a/vendor/golang.org/x/xerrors/codereview.cfg b/vendor/golang.org/x/xerrors/codereview.cfg
deleted file mode 100644
index 3f8b14b..0000000
--- a/vendor/golang.org/x/xerrors/codereview.cfg
+++ /dev/null
@@ -1 +0,0 @@
-issuerepo: golang/go
diff --git a/vendor/golang.org/x/xerrors/doc.go b/vendor/golang.org/x/xerrors/doc.go
deleted file mode 100644
index eef99d9..0000000
--- a/vendor/golang.org/x/xerrors/doc.go
+++ /dev/null
@@ -1,22 +0,0 @@
-// Copyright 2019 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package xerrors implements functions to manipulate errors.
-//
-// This package is based on the Go 2 proposal for error values:
-//   https://golang.org/design/29934-error-values
-//
-// These functions were incorporated into the standard library's errors package
-// in Go 1.13:
-// - Is
-// - As
-// - Unwrap
-//
-// Also, Errorf's %w verb was incorporated into fmt.Errorf.
-//
-// Use this package to get equivalent behavior in all supported Go versions.
-//
-// No other features of this package were included in Go 1.13, and at present
-// there are no plans to include any of them.
-package xerrors // import "golang.org/x/xerrors"
diff --git a/vendor/golang.org/x/xerrors/errors.go b/vendor/golang.org/x/xerrors/errors.go
deleted file mode 100644
index e88d377..0000000
--- a/vendor/golang.org/x/xerrors/errors.go
+++ /dev/null
@@ -1,33 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package xerrors
-
-import "fmt"
-
-// errorString is a trivial implementation of error.
-type errorString struct {
-	s     string
-	frame Frame
-}
-
-// New returns an error that formats as the given text.
-//
-// The returned error contains a Frame set to the caller's location and
-// implements Formatter to show this information when printed with details.
-func New(text string) error {
-	return &errorString{text, Caller(1)}
-}
-
-func (e *errorString) Error() string {
-	return e.s
-}
-
-func (e *errorString) Format(s fmt.State, v rune) { FormatError(e, s, v) }
-
-func (e *errorString) FormatError(p Printer) (next error) {
-	p.Print(e.s)
-	e.frame.Format(p)
-	return nil
-}
diff --git a/vendor/golang.org/x/xerrors/fmt.go b/vendor/golang.org/x/xerrors/fmt.go
deleted file mode 100644
index 829862d..0000000
--- a/vendor/golang.org/x/xerrors/fmt.go
+++ /dev/null
@@ -1,187 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package xerrors
-
-import (
-	"fmt"
-	"strings"
-	"unicode"
-	"unicode/utf8"
-
-	"golang.org/x/xerrors/internal"
-)
-
-const percentBangString = "%!"
-
-// Errorf formats according to a format specifier and returns the string as a
-// value that satisfies error.
-//
-// The returned error includes the file and line number of the caller when
-// formatted with additional detail enabled. If the last argument is an error
-// the returned error's Format method will return it if the format string ends
-// with ": %s", ": %v", or ": %w". If the last argument is an error and the
-// format string ends with ": %w", the returned error implements an Unwrap
-// method returning it.
-//
-// If the format specifier includes a %w verb with an error operand in a
-// position other than at the end, the returned error will still implement an
-// Unwrap method returning the operand, but the error's Format method will not
-// return the wrapped error.
-//
-// It is invalid to include more than one %w verb or to supply it with an
-// operand that does not implement the error interface. The %w verb is otherwise
-// a synonym for %v.
-func Errorf(format string, a ...interface{}) error {
-	format = formatPlusW(format)
-	// Support a ": %[wsv]" suffix, which works well with xerrors.Formatter.
-	wrap := strings.HasSuffix(format, ": %w")
-	idx, format2, ok := parsePercentW(format)
-	percentWElsewhere := !wrap && idx >= 0
-	if !percentWElsewhere && (wrap || strings.HasSuffix(format, ": %s") || strings.HasSuffix(format, ": %v")) {
-		err := errorAt(a, len(a)-1)
-		if err == nil {
-			return &noWrapError{fmt.Sprintf(format, a...), nil, Caller(1)}
-		}
-		// TODO: this is not entirely correct. The error value could be
-		// printed elsewhere in format if it mixes numbered with unnumbered
-		// substitutions. With relatively small changes to doPrintf we can
-		// have it optionally ignore extra arguments and pass the argument
-		// list in its entirety.
-		msg := fmt.Sprintf(format[:len(format)-len(": %s")], a[:len(a)-1]...)
-		frame := Frame{}
-		if internal.EnableTrace {
-			frame = Caller(1)
-		}
-		if wrap {
-			return &wrapError{msg, err, frame}
-		}
-		return &noWrapError{msg, err, frame}
-	}
-	// Support %w anywhere.
-	// TODO: don't repeat the wrapped error's message when %w occurs in the middle.
-	msg := fmt.Sprintf(format2, a...)
-	if idx < 0 {
-		return &noWrapError{msg, nil, Caller(1)}
-	}
-	err := errorAt(a, idx)
-	if !ok || err == nil {
-		// Too many %ws or argument of %w is not an error. Approximate the Go
-		// 1.13 fmt.Errorf message.
-		return &noWrapError{fmt.Sprintf("%sw(%s)", percentBangString, msg), nil, Caller(1)}
-	}
-	frame := Frame{}
-	if internal.EnableTrace {
-		frame = Caller(1)
-	}
-	return &wrapError{msg, err, frame}
-}
-
-func errorAt(args []interface{}, i int) error {
-	if i < 0 || i >= len(args) {
-		return nil
-	}
-	err, ok := args[i].(error)
-	if !ok {
-		return nil
-	}
-	return err
-}
-
-// formatPlusW is used to avoid the vet check that will barf at %w.
-func formatPlusW(s string) string {
-	return s
-}
-
-// Return the index of the only %w in format, or -1 if none.
-// Also return a rewritten format string with %w replaced by %v, and
-// false if there is more than one %w.
-// TODO: handle "%[N]w".
-func parsePercentW(format string) (idx int, newFormat string, ok bool) {
-	// Loosely copied from golang.org/x/tools/go/analysis/passes/printf/printf.go.
-	idx = -1
-	ok = true
-	n := 0
-	sz := 0
-	var isW bool
-	for i := 0; i < len(format); i += sz {
-		if format[i] != '%' {
-			sz = 1
-			continue
-		}
-		// "%%" is not a format directive.
-		if i+1 < len(format) && format[i+1] == '%' {
-			sz = 2
-			continue
-		}
-		sz, isW = parsePrintfVerb(format[i:])
-		if isW {
-			if idx >= 0 {
-				ok = false
-			} else {
-				idx = n
-			}
-			// "Replace" the last character, the 'w', with a 'v'.
-			p := i + sz - 1
-			format = format[:p] + "v" + format[p+1:]
-		}
-		n++
-	}
-	return idx, format, ok
-}
-
-// Parse the printf verb starting with a % at s[0].
-// Return how many bytes it occupies and whether the verb is 'w'.
-func parsePrintfVerb(s string) (int, bool) {
-	// Assume only that the directive is a sequence of non-letters followed by a single letter.
-	sz := 0
-	var r rune
-	for i := 1; i < len(s); i += sz {
-		r, sz = utf8.DecodeRuneInString(s[i:])
-		if unicode.IsLetter(r) {
-			return i + sz, r == 'w'
-		}
-	}
-	return len(s), false
-}
-
-type noWrapError struct {
-	msg   string
-	err   error
-	frame Frame
-}
-
-func (e *noWrapError) Error() string {
-	return fmt.Sprint(e)
-}
-
-func (e *noWrapError) Format(s fmt.State, v rune) { FormatError(e, s, v) }
-
-func (e *noWrapError) FormatError(p Printer) (next error) {
-	p.Print(e.msg)
-	e.frame.Format(p)
-	return e.err
-}
-
-type wrapError struct {
-	msg   string
-	err   error
-	frame Frame
-}
-
-func (e *wrapError) Error() string {
-	return fmt.Sprint(e)
-}
-
-func (e *wrapError) Format(s fmt.State, v rune) { FormatError(e, s, v) }
-
-func (e *wrapError) FormatError(p Printer) (next error) {
-	p.Print(e.msg)
-	e.frame.Format(p)
-	return e.err
-}
-
-func (e *wrapError) Unwrap() error {
-	return e.err
-}
diff --git a/vendor/golang.org/x/xerrors/format.go b/vendor/golang.org/x/xerrors/format.go
deleted file mode 100644
index 1bc9c26..0000000
--- a/vendor/golang.org/x/xerrors/format.go
+++ /dev/null
@@ -1,34 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package xerrors
-
-// A Formatter formats error messages.
-type Formatter interface {
-	error
-
-	// FormatError prints the receiver's first error and returns the next error in
-	// the error chain, if any.
-	FormatError(p Printer) (next error)
-}
-
-// A Printer formats error messages.
-//
-// The most common implementation of Printer is the one provided by package fmt
-// during Printf (as of Go 1.13). Localization packages such as golang.org/x/text/message
-// typically provide their own implementations.
-type Printer interface {
-	// Print appends args to the message output.
-	Print(args ...interface{})
-
-	// Printf writes a formatted string.
-	Printf(format string, args ...interface{})
-
-	// Detail reports whether error detail is requested.
-	// After the first call to Detail, all text written to the Printer
-	// is formatted as additional detail, or ignored when
-	// detail has not been requested.
-	// If Detail returns false, the caller can avoid printing the detail at all.
-	Detail() bool
-}
diff --git a/vendor/golang.org/x/xerrors/frame.go b/vendor/golang.org/x/xerrors/frame.go
deleted file mode 100644
index 0de628e..0000000
--- a/vendor/golang.org/x/xerrors/frame.go
+++ /dev/null
@@ -1,56 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package xerrors
-
-import (
-	"runtime"
-)
-
-// A Frame contains part of a call stack.
-type Frame struct {
-	// Make room for three PCs: the one we were asked for, what it called,
-	// and possibly a PC for skipPleaseUseCallersFrames. See:
-	// https://go.googlesource.com/go/+/032678e0fb/src/runtime/extern.go#169
-	frames [3]uintptr
-}
-
-// Caller returns a Frame that describes a frame on the caller's stack.
-// The argument skip is the number of frames to skip over.
-// Caller(0) returns the frame for the caller of Caller.
-func Caller(skip int) Frame {
-	var s Frame
-	runtime.Callers(skip+1, s.frames[:])
-	return s
-}
-
-// location reports the file, line, and function of a frame.
-//
-// The returned function may be "" even if file and line are not.
-func (f Frame) location() (function, file string, line int) {
-	frames := runtime.CallersFrames(f.frames[:])
-	if _, ok := frames.Next(); !ok {
-		return "", "", 0
-	}
-	fr, ok := frames.Next()
-	if !ok {
-		return "", "", 0
-	}
-	return fr.Function, fr.File, fr.Line
-}
-
-// Format prints the stack as error detail.
-// It should be called from an error's Format implementation
-// after printing any other error detail.
-func (f Frame) Format(p Printer) {
-	if p.Detail() {
-		function, file, line := f.location()
-		if function != "" {
-			p.Printf("%s\n    ", function)
-		}
-		if file != "" {
-			p.Printf("%s:%d\n", file, line)
-		}
-	}
-}
diff --git a/vendor/golang.org/x/xerrors/go.mod b/vendor/golang.org/x/xerrors/go.mod
deleted file mode 100644
index 870d4f6..0000000
--- a/vendor/golang.org/x/xerrors/go.mod
+++ /dev/null
@@ -1,3 +0,0 @@
-module golang.org/x/xerrors
-
-go 1.11
diff --git a/vendor/golang.org/x/xerrors/internal/internal.go b/vendor/golang.org/x/xerrors/internal/internal.go
deleted file mode 100644
index 89f4eca..0000000
--- a/vendor/golang.org/x/xerrors/internal/internal.go
+++ /dev/null
@@ -1,8 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package internal
-
-// EnableTrace indicates whether stack information should be recorded in errors.
-var EnableTrace = true
diff --git a/vendor/golang.org/x/xerrors/wrap.go b/vendor/golang.org/x/xerrors/wrap.go
deleted file mode 100644
index 9a3b510..0000000
--- a/vendor/golang.org/x/xerrors/wrap.go
+++ /dev/null
@@ -1,106 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package xerrors
-
-import (
-	"reflect"
-)
-
-// A Wrapper provides context around another error.
-type Wrapper interface {
-	// Unwrap returns the next error in the error chain.
-	// If there is no next error, Unwrap returns nil.
-	Unwrap() error
-}
-
-// Opaque returns an error with the same error formatting as err
-// but that does not match err and cannot be unwrapped.
-func Opaque(err error) error {
-	return noWrapper{err}
-}
-
-type noWrapper struct {
-	error
-}
-
-func (e noWrapper) FormatError(p Printer) (next error) {
-	if f, ok := e.error.(Formatter); ok {
-		return f.FormatError(p)
-	}
-	p.Print(e.error)
-	return nil
-}
-
-// Unwrap returns the result of calling the Unwrap method on err, if err implements
-// Unwrap. Otherwise, Unwrap returns nil.
-func Unwrap(err error) error {
-	u, ok := err.(Wrapper)
-	if !ok {
-		return nil
-	}
-	return u.Unwrap()
-}
-
-// Is reports whether any error in err's chain matches target.
-//
-// An error is considered to match a target if it is equal to that target or if
-// it implements a method Is(error) bool such that Is(target) returns true.
-func Is(err, target error) bool {
-	if target == nil {
-		return err == target
-	}
-
-	isComparable := reflect.TypeOf(target).Comparable()
-	for {
-		if isComparable && err == target {
-			return true
-		}
-		if x, ok := err.(interface{ Is(error) bool }); ok && x.Is(target) {
-			return true
-		}
-		// TODO: consider supporing target.Is(err). This would allow
-		// user-definable predicates, but also may allow for coping with sloppy
-		// APIs, thereby making it easier to get away with them.
-		if err = Unwrap(err); err == nil {
-			return false
-		}
-	}
-}
-
-// As finds the first error in err's chain that matches the type to which target
-// points, and if so, sets the target to its value and returns true. An error
-// matches a type if it is assignable to the target type, or if it has a method
-// As(interface{}) bool such that As(target) returns true. As will panic if target
-// is not a non-nil pointer to a type which implements error or is of interface type.
-//
-// The As method should set the target to its value and return true if err
-// matches the type to which target points.
-func As(err error, target interface{}) bool {
-	if target == nil {
-		panic("errors: target cannot be nil")
-	}
-	val := reflect.ValueOf(target)
-	typ := val.Type()
-	if typ.Kind() != reflect.Ptr || val.IsNil() {
-		panic("errors: target must be a non-nil pointer")
-	}
-	if e := typ.Elem(); e.Kind() != reflect.Interface && !e.Implements(errorType) {
-		panic("errors: *target must be interface or implement error")
-	}
-	targetType := typ.Elem()
-	for err != nil {
-		if reflect.TypeOf(err).AssignableTo(targetType) {
-			val.Elem().Set(reflect.ValueOf(err))
-			return true
-		}
-		if x, ok := err.(interface{ As(interface{}) bool }); ok && x.As(target) {
-			return true
-		}
-		err = Unwrap(err)
-	}
-	return false
-}
-
-var errorType = reflect.TypeOf((*error)(nil)).Elem()
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 98d85ba..46b0375 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -2,35 +2,38 @@
 ## explicit
 github.com/hashicorp/errwrap
 # github.com/hashicorp/go-multierror v1.1.1
-## explicit
+## explicit; go 1.13
 github.com/hashicorp/go-multierror
 # github.com/jpillora/opts v1.2.0
-## explicit
+## explicit; go 1.12
 github.com/jpillora/opts
 # github.com/posener/complete v1.2.3
-## explicit
+## explicit; go 1.13
 github.com/posener/complete
 github.com/posener/complete/cmd
 github.com/posener/complete/cmd/install
-# golang.org/x/mod v0.5.1
+# golang.org/x/mod v0.15.0
+## explicit; go 1.18
+golang.org/x/mod/internal/lazyregexp
+golang.org/x/mod/modfile
+golang.org/x/mod/module
 golang.org/x/mod/semver
-# golang.org/x/sys v0.1.0
-## explicit
-golang.org/x/sys/execabs
-# golang.org/x/tools v0.1.8
-## explicit
+# golang.org/x/tools v0.18.0
+## explicit; go 1.18
 golang.org/x/tools/go/gcexportdata
-golang.org/x/tools/go/internal/gcimporter
 golang.org/x/tools/go/internal/packagesdriver
 golang.org/x/tools/go/packages
+golang.org/x/tools/go/types/objectpath
 golang.org/x/tools/internal/event
 golang.org/x/tools/internal/event/core
 golang.org/x/tools/internal/event/keys
 golang.org/x/tools/internal/event/label
+golang.org/x/tools/internal/event/tag
+golang.org/x/tools/internal/gcimporter
 golang.org/x/tools/internal/gocommand
 golang.org/x/tools/internal/packagesinternal
+golang.org/x/tools/internal/pkgbits
+golang.org/x/tools/internal/tokeninternal
 golang.org/x/tools/internal/typeparams
 golang.org/x/tools/internal/typesinternal
-# golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1
-golang.org/x/xerrors
-golang.org/x/xerrors/internal
+golang.org/x/tools/internal/versions