diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
index 7f820f7..bde69c2 100644
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -13,7 +13,7 @@ jobs:
       - uses: actions/setup-go@v5
         with:
           go-version: stable
-      - uses: golangci/golangci-lint-action@v4
+      - uses: golangci/golangci-lint-action@v6
         with:
           version: v1.62.2
 
@@ -41,6 +41,9 @@ jobs:
       - name: Test code
         run: go test -race -v ./...
 
+      - name: Run
+        run: go run ./cmd/wsl/ ./...
+
   coverage:
     runs-on: ubuntu-latest
     steps:
diff --git a/.golangci.yml b/.golangci.yml
index 786b50c..6a349af 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -59,7 +59,6 @@ linters:
     - paralleltest
     - prealloc
     - rowserrcheck
-    - tparallel
     - testpackage
     - varnamelen
     - wastedassign
@@ -68,5 +67,4 @@ issues:
   exclude-use-default: true
   max-issues-per-linter: 0
   max-same-issues: 0
-
 # vim: set sw=2 ts=2 et:
diff --git a/analyzer.go b/analyzer.go
index 46d5019..9de53c3 100644
--- a/analyzer.go
+++ b/analyzer.go
@@ -3,6 +3,7 @@ package wsl
 import (
 	"flag"
 	"go/ast"
+	"go/token"
 	"strings"
 
 	"golang.org/x/tools/go/analysis"
@@ -82,7 +83,7 @@ func (wa *wslAnalyzer) run(pass *analysis.Pass) (interface{}, error) {
 			continue
 		}
 
-		filename := pass.Fset.PositionFor(file.Pos(), false).Filename
+		filename := getFilename(pass.Fset, file)
 		if !strings.HasSuffix(filename, ".go") {
 			continue
 		}
@@ -127,7 +128,7 @@ type multiStringValue struct {
 // Set implements the flag.Value interface and will overwrite the pointer to the
 // slice with a new pointer after splitting the flag by comma.
 func (m *multiStringValue) Set(value string) error {
-	s := []string{}
+	var s []string
 
 	for _, v := range strings.Split(value, ",") {
 		s = append(s, strings.TrimSpace(v))
@@ -146,3 +147,12 @@ func (m *multiStringValue) String() string {
 
 	return strings.Join(*m.slicePtr, ", ")
 }
+
+func getFilename(fset *token.FileSet, file *ast.File) string {
+	filename := fset.PositionFor(file.Pos(), true).Filename
+	if !strings.HasSuffix(filename, ".go") {
+		return fset.PositionFor(file.Pos(), false).Filename
+	}
+
+	return filename
+}
diff --git a/go.mod b/go.mod
index be3cd12..aaafe53 100644
--- a/go.mod
+++ b/go.mod
@@ -1,10 +1,7 @@
 module github.com/bombsimon/wsl/v4
 
-go 1.21
+go 1.22
 
 require golang.org/x/tools v0.17.0
 
-require (
-	golang.org/x/mod v0.15.0 // indirect
-	golang.org/x/sys v0.17.0 // indirect
-)
+require golang.org/x/mod v0.15.0 // indirect
diff --git a/go.sum b/go.sum
index bdce42b..f3a7dec 100644
--- a/go.sum
+++ b/go.sum
@@ -1,13 +1,6 @@
-golang.org/x/mod v0.8.0 h1:LUYupSeNrTNCGzR/hVBk2NHZO4hXcVaW1k4Qx7rjPx8=
-golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
 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 v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
-golang.org/x/sys v0.5.0 h1:MUK/U/4lj1t1oPg0HfuXDN/Z1wv31ZJ/YcPiGccS4DU=
-golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.17.0 h1:25cE3gD+tdBA7lp7QfhuV+rJiE9YXTcS3VG1SqssI/Y=
-golang.org/x/sys v0.17.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/tools v0.6.0 h1:BOw41kyTf3PuCW1pVQf8+Cyg8pMlkYB1oo9iJ6D/lKM=
-golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
+golang.org/x/sync v0.6.0 h1:5BMeUDZ7vkXGfEr1x9B4bRcTH4lpkTkpdh0T/J+qjbQ=
+golang.org/x/sync v0.6.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/tools v0.17.0 h1:FvmRgNOcs3kOa+T20R1uhfP9F6HgG2mfxDv1vrx1Htc=
 golang.org/x/tools v0.17.0/go.mod h1:xsh6VxdV005rRVaS6SSAf9oiAqljS7UZUacMZ8Bnsps=
diff --git a/testdata/src/default_config/cgo.go b/testdata/src/default_config/cgo.go
new file mode 100644
index 0000000..56f8905
--- /dev/null
+++ b/testdata/src/default_config/cgo.go
@@ -0,0 +1,42 @@
+package testpkg
+
+/*
+ #include <stdio.h>
+ #include <stdlib.h>
+
+ void myprint(char* s) {
+ 	printf("%d\n", s);
+ }
+*/
+import "C"
+
+import (
+	"unsafe"
+)
+
+func _() {
+	cs := C.CString("Hello from stdio\n")
+	C.myprint(cs)
+	C.free(unsafe.Pointer(cs))
+}
+
+func Advanced() {
+	var foo = 1
+	var bar = 2 // want "declarations should never be cuddled"
+	var biz int // want "declarations should never be cuddled"
+
+	x := []string{}
+	x = append(x, "literal")
+	notUsed := "just assigning, don't mind me"
+	x = append(x, "not z..") // want "append only allowed to cuddle with appended value"
+	useMe := "right away"
+	alsoNotUsed := ":("
+	x = append(x, "just noise") // want "append only allowed to cuddle with appended value"
+	x = append(x, useMe)
+
+	_ = foo
+	_ = bar
+	_ = biz
+	_ = notUsed
+	_ = alsoNotUsed
+}
diff --git a/testdata/src/default_config/cgo.go.golden b/testdata/src/default_config/cgo.go.golden
new file mode 100644
index 0000000..5789e81
--- /dev/null
+++ b/testdata/src/default_config/cgo.go.golden
@@ -0,0 +1,46 @@
+package testpkg
+
+/*
+ #include <stdio.h>
+ #include <stdlib.h>
+
+ void myprint(char* s) {
+ 	printf("%d\n", s);
+ }
+*/
+import "C"
+
+import (
+	"unsafe"
+)
+
+func _() {
+	cs := C.CString("Hello from stdio\n")
+	C.myprint(cs)
+	C.free(unsafe.Pointer(cs))
+}
+
+func Advanced() {
+	var foo = 1
+
+	var bar = 2 // want "declarations should never be cuddled"
+
+	var biz int // want "declarations should never be cuddled"
+
+	x := []string{}
+	x = append(x, "literal")
+	notUsed := "just assigning, don't mind me"
+
+	x = append(x, "not z..") // want "append only allowed to cuddle with appended value"
+	useMe := "right away"
+	alsoNotUsed := ":("
+
+	x = append(x, "just noise") // want "append only allowed to cuddle with appended value"
+	x = append(x, useMe)
+
+	_ = foo
+	_ = bar
+	_ = biz
+	_ = notUsed
+	_ = alsoNotUsed
+}
diff --git a/testdata/src/default_config/line_directive.go b/testdata/src/default_config/line_directive.go
new file mode 100644
index 0000000..d7e1ed7
--- /dev/null
+++ b/testdata/src/default_config/line_directive.go
@@ -0,0 +1,41 @@
+//line line_directive.tmpl:1
+package pkg
+
+import (
+	"fmt"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+func _() {
+	var x int
+	_ = x
+	x = 0 // x
+}
+
+func main() {
+	a()
+	b()
+	wsl()
+}
+
+func a() {
+	fmt.Println("foo")
+}
+
+func b() {
+	fmt.Println("foo")
+}
+
+func c() {
+	_ = analysis.Analyzer{}
+}
+
+// want +1 "block should not start with a whitespace"
+func wsl() bool {
+
+	return true
+}
+
+func notFormatted() {
+}
diff --git a/testdata/src/default_config/line_directive.go.golden b/testdata/src/default_config/line_directive.go.golden
new file mode 100644
index 0000000..846c1ba
--- /dev/null
+++ b/testdata/src/default_config/line_directive.go.golden
@@ -0,0 +1,40 @@
+//line line_directive.tmpl:1
+package pkg
+
+import (
+	"fmt"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+func _() {
+	var x int
+	_ = x
+	x = 0 // x
+}
+
+func main() {
+	a()
+	b()
+	wsl()
+}
+
+func a() {
+	fmt.Println("foo")
+}
+
+func b() {
+	fmt.Println("foo")
+}
+
+func c() {
+	_ = analysis.Analyzer{}
+}
+
+// want +1 "block should not start with a whitespace"
+func wsl() bool {
+	return true
+}
+
+func notFormatted() {
+}
diff --git a/testdata/src/default_config/line_directive.tmpl b/testdata/src/default_config/line_directive.tmpl
new file mode 100644
index 0000000..082dc6f
--- /dev/null
+++ b/testdata/src/default_config/line_directive.tmpl
@@ -0,0 +1 @@
+# This is a template file for some code generator, and is not a valid go source file.
diff --git a/wsl.go b/wsl.go
index 76f4abf..44c7abe 100644
--- a/wsl.go
+++ b/wsl.go
@@ -353,7 +353,7 @@ func (p *processor) parseBlockStatements(statements []ast.Stmt) {
 				return false
 			}
 
-			for j := 0; j < n; j++ {
+			for j := range n {
 				s1 := statements[i+j]
 				s2 := statements[i+j+1]
 
@@ -1113,8 +1113,8 @@ func (p *processor) findLeadingAndTrailingWhitespaces(ident *ast.Ident, stmt, ne
 		return
 	}
 
-	blockStartLine = p.fileSet.PositionFor(blockStartPos, false).Line
-	blockEndLine = p.fileSet.PositionFor(blockEndPos, false).Line
+	blockStartLine = p.fileSet.Position(blockStartPos).Line
+	blockEndLine = p.fileSet.Position(blockEndPos).Line
 
 	// No whitespace possible if LBrace and RBrace is on the same line.
 	if blockStartLine == blockEndLine {
@@ -1362,14 +1362,14 @@ func isExampleFunc(ident *ast.Ident) bool {
 }
 
 func (p *processor) nodeStart(node ast.Node) int {
-	return p.fileSet.PositionFor(node.Pos(), false).Line
+	return p.fileSet.Position(node.Pos()).Line
 }
 
 func (p *processor) nodeEnd(node ast.Node) int {
-	line := p.fileSet.PositionFor(node.End(), false).Line
+	line := p.fileSet.Position(node.End()).Line
 
 	if isEmptyLabeledStmt(node) {
-		return p.fileSet.PositionFor(node.Pos(), false).Line
+		return p.fileSet.Position(node.Pos()).Line
 	}
 
 	return line
@@ -1408,7 +1408,7 @@ func (p *processor) addErrorRange(reportAt, start, end token.Pos, reason string)
 }
 
 func (p *processor) addWarning(w string, pos token.Pos, t interface{}) {
-	position := p.fileSet.PositionFor(pos, false)
+	position := p.fileSet.Position(pos)
 
 	p.warnings = append(p.warnings,
 		fmt.Sprintf("%s:%d: %s (%T)", position.Filename, position.Line, w, t),
diff --git a/wsl_test.go b/wsl_test.go
index 78243be..b845657 100644
--- a/wsl_test.go
+++ b/wsl_test.go
@@ -15,6 +15,8 @@ func TestWIP(t *testing.T) {
 }
 
 func TestDefaultConfig(t *testing.T) {
+	t.Parallel()
+
 	testdata := analysistest.TestData()
 
 	testCases := []struct {