diff --git a/.azure-pipelines/steps/run.yml b/.azure-pipelines/steps/run.yml
index a646b34fe7d02..49bac629e7285 100644
--- a/.azure-pipelines/steps/run.yml
+++ b/.azure-pipelines/steps/run.yml
@@ -74,8 +74,9 @@ steps:
 # images, etc.
 - bash: |
     set -e
+    source src/ci/shared.sh
     sudo apt-get install -y python3-setuptools
-    pip3 install awscli --upgrade --user
+    retry pip3 install awscli --upgrade --user
     echo "##vso[task.prependpath]$HOME/.local/bin"
   displayName: Install awscli (Linux)
   condition: and(succeeded(), eq(variables['Agent.OS'], 'Linux'))
diff --git a/Cargo.lock b/Cargo.lock
index 948074ce0fc48..40c8047e8a2ac 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1813,6 +1813,7 @@ name = "panic_unwind"
 version = "0.0.0"
 dependencies = [
  "alloc 0.0.0",
+ "cfg-if 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "compiler_builtins 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3338,6 +3339,7 @@ dependencies = [
  "alloc 0.0.0",
  "backtrace 0.3.29 (registry+https://github.com/rust-lang/crates.io-index)",
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "compiler_builtins 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "dlmalloc 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3936,6 +3938,7 @@ name = "unwind"
 version = "0.0.0"
 dependencies = [
  "cc 1.0.35 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "compiler_builtins 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "core 0.0.0",
  "libc 0.2.54 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/README.md b/README.md
index b522b161ecf93..15d09f4aada3b 100644
--- a/README.md
+++ b/README.md
@@ -130,9 +130,9 @@ build.
 
 MSVC builds of Rust additionally require an installation of Visual Studio 2017
 (or later) so `rustc` can use its linker.  The simplest way is to get the
-[Visual Studio Build Tools] and check the “C++ build tools” workload.
+[Visual Studio], check the “C++ build tools” and “Windows 10 SDK” workload.
 
-[Visual Studio Build Tools]: https://visualstudio.microsoft.com/downloads/#build-tools-for-visual-studio-2019
+[Visual Studio]: https://visualstudio.microsoft.com/downloads/
 
 (If you're installing cmake yourself, be careful that “C++ CMake tools for
 Windows” doesn't get included under “Individual components”.)
diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 2281a45e014a9..c665a618fbc36 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -1693,10 +1693,6 @@ mod __test {
                     compiler: Compiler { host: a, stage: 1 },
                     target: b,
                 },
-                compile::Std {
-                    compiler: Compiler { host: a, stage: 2 },
-                    target: b,
-                },
             ]
         );
         assert_eq!(
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index 2a3577a3d2044..6fd94285ff9c7 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -46,10 +46,11 @@ macro_rules! book {
             }
 
             fn run(self, builder: &Builder<'_>) {
-                builder.ensure(Rustbook {
+                builder.ensure(RustbookSrc {
                     target: self.target,
                     name: INTERNER.intern_str($book_name),
                     version: $book_ver,
+                    src: doc_src(builder),
                 })
             }
         }
@@ -75,35 +76,8 @@ enum RustbookVersion {
     MdBook2,
 }
 
-#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
-struct Rustbook {
-    target: Interned<String>,
-    name: Interned<String>,
-    version: RustbookVersion,
-}
-
-impl Step for Rustbook {
-    type Output = ();
-
-    // rustbook is never directly called, and only serves as a shim for the nomicon and the
-    // reference.
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.never()
-    }
-
-    /// Invoke `rustbook` for `target` for the doc book `name`.
-    ///
-    /// This will not actually generate any documentation if the documentation has
-    /// already been generated.
-    fn run(self, builder: &Builder<'_>) {
-        let src = builder.src.join("src/doc");
-        builder.ensure(RustbookSrc {
-            target: self.target,
-            name: self.name,
-            src: INTERNER.intern_path(src),
-            version: self.version,
-        });
-    }
+fn doc_src(builder: &Builder<'_>) -> Interned<PathBuf> {
+    INTERNER.intern_path(builder.src.join("src/doc"))
 }
 
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
@@ -274,33 +248,37 @@ impl Step for TheBook {
         let name = self.name;
 
         // build book
-        builder.ensure(Rustbook {
+        builder.ensure(RustbookSrc {
             target,
             name: INTERNER.intern_string(name.to_string()),
             version: RustbookVersion::MdBook2,
+            src: doc_src(builder),
         });
 
         // building older edition redirects
 
         let source_name = format!("{}/first-edition", name);
-        builder.ensure(Rustbook {
+        builder.ensure(RustbookSrc {
             target,
             name: INTERNER.intern_string(source_name),
             version: RustbookVersion::MdBook2,
+            src: doc_src(builder),
         });
 
         let source_name = format!("{}/second-edition", name);
-        builder.ensure(Rustbook {
+        builder.ensure(RustbookSrc {
             target,
             name: INTERNER.intern_string(source_name),
             version: RustbookVersion::MdBook2,
+            src: doc_src(builder),
         });
 
         let source_name = format!("{}/2018-edition", name);
-        builder.ensure(Rustbook {
+        builder.ensure(RustbookSrc {
             target,
             name: INTERNER.intern_string(source_name),
             version: RustbookVersion::MdBook2,
+            src: doc_src(builder),
         });
 
         // build the version info page and CSS
@@ -898,11 +876,6 @@ impl Step for UnstableBookGen {
     fn run(self, builder: &Builder<'_>) {
         let target = self.target;
 
-        builder.ensure(compile::Std {
-            compiler: builder.compiler(builder.top_stage, builder.config.build),
-            target,
-        });
-
         builder.info(&format!("Generating unstable book md files ({})", target));
         let out = builder.md_doc_out(target).join("unstable-book");
         builder.create_dir(&out);
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index b9d287abb0c7e..7f652c0d7a776 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -270,14 +270,9 @@ pub struct Build {
 #[derive(Debug)]
 struct Crate {
     name: Interned<String>,
-    version: String,
     deps: HashSet<Interned<String>>,
     id: String,
     path: PathBuf,
-    doc_step: String,
-    build_step: String,
-    test_step: String,
-    bench_step: String,
 }
 
 impl Crate {
diff --git a/src/bootstrap/metadata.rs b/src/bootstrap/metadata.rs
index 4a71fd2ce0bd2..b622b3682a777 100644
--- a/src/bootstrap/metadata.rs
+++ b/src/bootstrap/metadata.rs
@@ -20,7 +20,6 @@ struct Output {
 struct Package {
     id: String,
     name: String,
-    version: String,
     source: Option<String>,
     manifest_path: String,
 }
@@ -84,12 +83,7 @@ fn build_krate(features: &str, build: &mut Build, resolves: &mut Vec<ResolveNode
             let mut path = PathBuf::from(package.manifest_path);
             path.pop();
             build.crates.insert(name, Crate {
-                build_step: format!("build-crate-{}", name),
-                doc_step: format!("doc-crate-{}", name),
-                test_step: format!("test-crate-{}", name),
-                bench_step: format!("bench-crate-{}", name),
                 name,
-                version: package.version,
                 id: package.id,
                 deps: HashSet::new(),
                 path,
diff --git a/src/bootstrap/tool.rs b/src/bootstrap/tool.rs
index 83a897f1ab74f..ca7ed94c04123 100644
--- a/src/bootstrap/tool.rs
+++ b/src/bootstrap/tool.rs
@@ -268,10 +268,6 @@ macro_rules! bootstrap_tool {
         }
 
         impl Tool {
-            pub fn get_mode(&self) -> Mode {
-                Mode::ToolBootstrap
-            }
-
             /// Whether this tool requires LLVM to run
             pub fn uses_llvm_tools(&self) -> bool {
                 match self {
@@ -345,6 +341,7 @@ bootstrap_tool!(
     Compiletest, "src/tools/compiletest", "compiletest", llvm_tools = true;
     BuildManifest, "src/tools/build-manifest", "build-manifest";
     RemoteTestClient, "src/tools/remote-test-client", "remote-test-client";
+    RemoteTestServer, "src/tools/remote-test-server", "remote-test-server";
     RustInstaller, "src/tools/rust-installer", "fabricate", is_external_tool = true;
     RustdocTheme, "src/tools/rustdoc-themes", "rustdoc-themes";
 );
@@ -397,40 +394,6 @@ impl Step for ErrorIndex {
     }
 }
 
-#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
-pub struct RemoteTestServer {
-    pub compiler: Compiler,
-    pub target: Interned<String>,
-}
-
-impl Step for RemoteTestServer {
-    type Output = PathBuf;
-
-    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        run.path("src/tools/remote-test-server")
-    }
-
-    fn make_run(run: RunConfig<'_>) {
-        run.builder.ensure(RemoteTestServer {
-            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
-            target: run.target,
-        });
-    }
-
-    fn run(self, builder: &Builder<'_>) -> PathBuf {
-        builder.ensure(ToolBuild {
-            compiler: self.compiler,
-            target: self.target,
-            tool: "remote-test-server",
-            mode: Mode::ToolStd,
-            path: "src/tools/remote-test-server",
-            is_optional_tool: false,
-            source_type: SourceType::InTree,
-            extra_features: Vec::new(),
-        }).expect("expected to build -- essential tool")
-    }
-}
-
 #[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct Rustdoc {
     /// This should only ever be 0 or 2.
@@ -659,23 +622,14 @@ impl<'a> Builder<'a> {
     pub fn tool_cmd(&self, tool: Tool) -> Command {
         let mut cmd = Command::new(self.tool_exe(tool));
         let compiler = self.compiler(0, self.config.build);
-        self.prepare_tool_cmd(compiler, tool, &mut cmd);
-        cmd
-    }
-
-    /// Prepares the `cmd` provided to be able to run the `compiler` provided.
-    ///
-    /// Notably this munges the dynamic library lookup path to point to the
-    /// right location to run `compiler`.
-    fn prepare_tool_cmd(&self, compiler: Compiler, tool: Tool, cmd: &mut Command) {
         let host = &compiler.host;
+        // Prepares the `cmd` provided to be able to run the `compiler` provided.
+        //
+        // Notably this munges the dynamic library lookup path to point to the
+        // right location to run `compiler`.
         let mut lib_paths: Vec<PathBuf> = vec![
-            if compiler.stage == 0 {
-                self.build.rustc_snapshot_libdir()
-            } else {
-                PathBuf::from(&self.sysroot_libdir(compiler, compiler.host))
-            },
-            self.cargo_out(compiler, tool.get_mode(), *host).join("deps"),
+            self.build.rustc_snapshot_libdir(),
+            self.cargo_out(compiler, Mode::ToolBootstrap, *host).join("deps"),
         ];
 
         // On MSVC a tool may invoke a C compiler (e.g., compiletest in run-make
@@ -696,6 +650,7 @@ impl<'a> Builder<'a> {
             }
         }
 
-        add_lib_path(lib_paths, cmd);
+        add_lib_path(lib_paths, &mut cmd);
+        cmd
     }
 }
diff --git a/src/libcore/hint.rs b/src/libcore/hint.rs
index 94eddbeda2b86..519212bb6cb4e 100644
--- a/src/libcore/hint.rs
+++ b/src/libcore/hint.rs
@@ -111,31 +111,31 @@ pub fn spin_loop() {
 /// This function is a no-op, and does not even read from `dummy`.
 #[inline]
 #[unstable(feature = "test", issue = "27812")]
+#[allow(unreachable_code)] // this makes #[cfg] a bit easier below.
 pub fn black_box<T>(dummy: T) -> T {
-    cfg_if! {
-        if #[cfg(any(
-            target_arch = "asmjs",
-            all(
-                target_arch = "wasm32",
-                target_os = "emscripten"
-            )
-        ))] {
-            #[inline]
-            unsafe fn black_box_impl<T>(d: T) -> T {
-                // these targets do not support inline assembly
-                let ret = crate::ptr::read_volatile(&d);
-                crate::mem::forget(d);
-                ret
-            }
-        } else {
-            #[inline]
-            unsafe fn black_box_impl<T>(d: T) -> T {
-                // we need to "use" the argument in some way LLVM can't
-                // introspect.
-                asm!("" : : "r"(&d));
-                d
-            }
-        }
+    // We need to "use" the argument in some way LLVM can't introspect, and on
+    // targets that support it we can typically leverage inline assembly to do
+    // this. LLVM's intepretation of inline assembly is that it's, well, a black
+    // box. This isn't the greatest implementation since it probably deoptimizes
+    // more than we want, but it's so far good enough.
+    #[cfg(not(any(
+        target_arch = "asmjs",
+        all(
+            target_arch = "wasm32",
+            target_os = "emscripten"
+        )
+    )))]
+    unsafe {
+        asm!("" : : "r"(&dummy));
+        return dummy;
+    }
+
+    // Not all platforms support inline assembly so try to do something without
+    // inline assembly which in theory still hinders at least some optimizations
+    // on those targets. This is the "best effort" scenario.
+    unsafe {
+        let ret = crate::ptr::read_volatile(&dummy);
+        crate::mem::forget(dummy);
+        ret
     }
-    unsafe { black_box_impl(dummy) }
 }
diff --git a/src/libcore/internal_macros.rs b/src/libcore/internal_macros.rs
index dd5b92857be63..3acf2ec837d88 100644
--- a/src/libcore/internal_macros.rs
+++ b/src/libcore/internal_macros.rs
@@ -117,84 +117,3 @@ macro_rules! impl_fn_for_zst {
         )+
     }
 }
-
-/// A macro for defining `#[cfg]` if-else statements.
-///
-/// The macro provided by this crate, `cfg_if`, is similar to the `if/elif` C
-/// preprocessor macro by allowing definition of a cascade of `#[cfg]` cases,
-/// emitting the implementation which matches first.
-///
-/// This allows you to conveniently provide a long list `#[cfg]`'d blocks of code
-/// without having to rewrite each clause multiple times.
-///
-/// # Example
-///
-/// ```
-/// #[macro_use]
-/// extern crate cfg_if;
-///
-/// cfg_if! {
-///     if #[cfg(unix)] {
-///         fn foo() { /* unix specific functionality */ }
-///     } else if #[cfg(target_pointer_width = "32")] {
-///         fn foo() { /* non-unix, 32-bit functionality */ }
-///     } else {
-///         fn foo() { /* fallback implementation */ }
-///     }
-/// }
-///
-/// # fn main() {}
-/// ```
-macro_rules! cfg_if {
-    // match if/else chains with a final `else`
-    ($(
-        if #[cfg($($meta:meta),*)] { $($it:item)* }
-    ) else * else {
-        $($it2:item)*
-    }) => {
-        cfg_if! {
-            @__items
-            () ;
-            $( ( ($($meta),*) ($($it)*) ), )*
-            ( () ($($it2)*) ),
-        }
-    };
-
-    // match if/else chains lacking a final `else`
-    (
-        if #[cfg($($i_met:meta),*)] { $($i_it:item)* }
-        $(
-            else if #[cfg($($e_met:meta),*)] { $($e_it:item)* }
-        )*
-    ) => {
-        cfg_if! {
-            @__items
-            () ;
-            ( ($($i_met),*) ($($i_it)*) ),
-            $( ( ($($e_met),*) ($($e_it)*) ), )*
-            ( () () ),
-        }
-    };
-
-    // Internal and recursive macro to emit all the items
-    //
-    // Collects all the negated cfgs in a list at the beginning and after the
-    // semicolon is all the remaining items
-    (@__items ($($not:meta,)*) ; ) => {};
-    (@__items ($($not:meta,)*) ; ( ($($m:meta),*) ($($it:item)*) ), $($rest:tt)*) => {
-        // Emit all items within one block, applying an approprate #[cfg]. The
-        // #[cfg] will require all `$m` matchers specified and must also negate
-        // all previous matchers.
-        cfg_if! { @__apply cfg(all($($m,)* not(any($($not),*)))), $($it)* }
-
-        // Recurse to emit all other items in `$rest`, and when we do so add all
-        // our `$m` matchers to the list of `$not` matchers as future emissions
-        // will have to negate everything we just matched as well.
-        cfg_if! { @__items ($($not,)* $($m,)*) ; $($rest)* }
-    };
-
-    // Internal macro to Apply a cfg attribute to a list of items
-    (@__apply $m:meta, $($it:item)*) => {
-        $(#[$m] $it)*
-    };
-}
diff --git a/src/libcore/iter/traits/iterator.rs b/src/libcore/iter/traits/iterator.rs
index d0fdd79473e67..30923c7414504 100644
--- a/src/libcore/iter/traits/iterator.rs
+++ b/src/libcore/iter/traits/iterator.rs
@@ -1495,13 +1495,13 @@ pub trait Iterator {
         let mut left: B = Default::default();
         let mut right: B = Default::default();
 
-        for x in self {
+        self.for_each(|x| {
             if f(&x) {
                 left.extend(Some(x))
             } else {
                 right.extend(Some(x))
             }
-        }
+        });
 
         (left, right)
     }
diff --git a/src/libcore/slice/mod.rs b/src/libcore/slice/mod.rs
index 0e782bef39dd8..c9c73f4d66ee9 100644
--- a/src/libcore/slice/mod.rs
+++ b/src/libcore/slice/mod.rs
@@ -5420,7 +5420,7 @@ macro_rules! impl_marker_for {
 }
 
 impl_marker_for!(BytewiseEquality,
-                 u8 i8 u16 i16 u32 i32 u64 i64 usize isize char bool);
+                 u8 i8 u16 i16 u32 i32 u64 i64 u128 i128 usize isize char bool);
 
 #[doc(hidden)]
 unsafe impl<'a, T> TrustedRandomAccess for Iter<'a, T> {
diff --git a/src/libcore/str/mod.rs b/src/libcore/str/mod.rs
index 8a128b0d5e7b2..34f2d8917ea47 100644
--- a/src/libcore/str/mod.rs
+++ b/src/libcore/str/mod.rs
@@ -4000,11 +4000,11 @@ impl str {
     /// # Examples
     ///
     /// ```
-    /// let mut s = String::from("Grüße, Jürgen ❤");
+    /// let mut s = String::from("GRÜßE, JÜRGEN ❤");
     ///
     /// s.make_ascii_lowercase();
     ///
-    /// assert_eq!("grüße, jürgen ❤", s);
+    /// assert_eq!("grÜße, jÜrgen ❤", s);
     /// ```
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
     pub fn make_ascii_lowercase(&mut self) {
diff --git a/src/libpanic_unwind/Cargo.toml b/src/libpanic_unwind/Cargo.toml
index 1b3901ac11a96..47cd09f1b0510 100644
--- a/src/libpanic_unwind/Cargo.toml
+++ b/src/libpanic_unwind/Cargo.toml
@@ -16,3 +16,4 @@ core = { path = "../libcore" }
 libc = { version = "0.2", default-features = false }
 unwind = { path = "../libunwind" }
 compiler_builtins = "0.1.0"
+cfg-if = "0.1.8"
diff --git a/src/libpanic_unwind/lib.rs b/src/libpanic_unwind/lib.rs
index 72ddafb420ce7..2bb9ce6ab220b 100644
--- a/src/libpanic_unwind/lib.rs
+++ b/src/libpanic_unwind/lib.rs
@@ -38,10 +38,7 @@ use core::mem;
 use core::raw;
 use core::panic::BoxMeUp;
 
-#[macro_use]
-mod macros;
-
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(target_os = "emscripten")] {
         #[path = "emcc.rs"]
         mod imp;
diff --git a/src/libpanic_unwind/macros.rs b/src/libpanic_unwind/macros.rs
deleted file mode 100644
index 659e977285e35..0000000000000
--- a/src/libpanic_unwind/macros.rs
+++ /dev/null
@@ -1,35 +0,0 @@
-/// A macro for defining `#[cfg]` if-else statements.
-///
-/// This is similar to the `if/elif` C preprocessor macro by allowing definition
-/// of a cascade of `#[cfg]` cases, emitting the implementation which matches
-/// first.
-///
-/// This allows you to conveniently provide a long list `#[cfg]`'d blocks of code
-/// without having to rewrite each clause multiple times.
-macro_rules! cfg_if {
-    ($(
-        if #[cfg($($meta:meta),*)] { $($it:item)* }
-    ) else * else {
-        $($it2:item)*
-    }) => {
-        __cfg_if_items! {
-            () ;
-            $( ( ($($meta),*) ($($it)*) ), )*
-            ( () ($($it2)*) ),
-        }
-    }
-}
-
-macro_rules! __cfg_if_items {
-    (($($not:meta,)*) ; ) => {};
-    (($($not:meta,)*) ; ( ($($m:meta),*) ($($it:item)*) ), $($rest:tt)*) => {
-        __cfg_if_apply! { cfg(all(not(any($($not),*)), $($m,)*)), $($it)* }
-        __cfg_if_items! { ($($not,)* $($m,)*) ; $($rest)* }
-    }
-}
-
-macro_rules! __cfg_if_apply {
-    ($m:meta, $($it:item)*) => {
-        $(#[$m] $it)*
-    }
-}
diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs
index 003fdd501a35a..86a606b5fd3d6 100644
--- a/src/librustc/session/config.rs
+++ b/src/librustc/session/config.rs
@@ -227,13 +227,17 @@ impl OutputType {
     }
 }
 
+/// The type of diagnostics output to generate.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum ErrorOutputType {
+    /// Output meant for the consumption of humans.
     HumanReadable(HumanReadableErrorType),
+    /// Output that's consumed by other tools such as `rustfix` or the `RLS`.
     Json {
-        /// Render the json in a human readable way (with indents and newlines)
+        /// Render the JSON in a human readable way (with indents and newlines).
         pretty: bool,
-        /// The way the `rendered` field is created
+        /// The JSON output includes a `rendered` field that includes the rendered
+        /// human output.
         json_rendered: HumanReadableErrorType,
     },
 }
diff --git a/src/librustc_errors/diagnostic_builder.rs b/src/librustc_errors/diagnostic_builder.rs
index 31f697a724a03..fc74e43ff5739 100644
--- a/src/librustc_errors/diagnostic_builder.rs
+++ b/src/librustc_errors/diagnostic_builder.rs
@@ -348,7 +348,7 @@ impl<'a> DiagnosticBuilder<'a> {
 
     /// Convenience function for internal use, clients should use one of the
     /// struct_* methods on Handler.
-    pub fn new_with_code(handler: &'a Handler,
+    crate fn new_with_code(handler: &'a Handler,
                          level: Level,
                          code: Option<DiagnosticId>,
                          message: &str)
diff --git a/src/librustc_errors/emitter.rs b/src/librustc_errors/emitter.rs
index 3bf477efe35f9..fca8298409a61 100644
--- a/src/librustc_errors/emitter.rs
+++ b/src/librustc_errors/emitter.rs
@@ -1,3 +1,12 @@
+//! The current rustc diagnostics emitter.
+//!
+//! An `Emitter` takes care of generating the output from a `DiagnosticBuilder` struct.
+//!
+//! There are various `Emitter` implementations that generate different output formats such as
+//! JSON and human readable output.
+//!
+//! The output types are defined in `librustc::session::config::ErrorOutputType`.
+
 use Destination::*;
 
 use syntax_pos::{SourceFile, Span, MultiSpan};
diff --git a/src/librustc_errors/lib.rs b/src/librustc_errors/lib.rs
index cc3180c783bdf..6ec1b90cd91cd 100644
--- a/src/librustc_errors/lib.rs
+++ b/src/librustc_errors/lib.rs
@@ -1,5 +1,10 @@
+//! Diagnostics creation and emission for `rustc`.
+//!
+//! This module contains the code for creating and emitting diagnostics.
+
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 
+#![feature(crate_visibility_modifier)]
 #![allow(unused_attributes)]
 #![cfg_attr(unix, feature(libc))]
 #![feature(nll)]
diff --git a/src/librustc_metadata/creader.rs b/src/librustc_metadata/creader.rs
index 991bebc647d0f..7ffba41e2569a 100644
--- a/src/librustc_metadata/creader.rs
+++ b/src/librustc_metadata/creader.rs
@@ -614,7 +614,7 @@ impl<'a> CrateLoader<'a> {
             match decl {
                 ProcMacro::CustomDerive { trait_name, attributes, client } => {
                     let attrs = attributes.iter().cloned().map(Symbol::intern).collect::<Vec<_>>();
-                    (trait_name, SyntaxExtension::ProcMacroDerive(
+                    (trait_name, SyntaxExtension::Derive(
                         Box::new(ProcMacroDerive {
                             client,
                             attrs: attrs.clone(),
@@ -624,13 +624,13 @@ impl<'a> CrateLoader<'a> {
                     ))
                 }
                 ProcMacro::Attr { name, client } => {
-                    (name, SyntaxExtension::AttrProcMacro(
+                    (name, SyntaxExtension::Attr(
                         Box::new(AttrProcMacro { client }),
                         root.edition,
                     ))
                 }
                 ProcMacro::Bang { name, client } => {
-                    (name, SyntaxExtension::ProcMacro {
+                    (name, SyntaxExtension::Bang {
                         expander: Box::new(BangProcMacro { client }),
                         allow_internal_unstable: None,
                         edition: root.edition,
diff --git a/src/librustc_metadata/cstore_impl.rs b/src/librustc_metadata/cstore_impl.rs
index db452bb4ac7bc..35faa1df82b84 100644
--- a/src/librustc_metadata/cstore_impl.rs
+++ b/src/librustc_metadata/cstore_impl.rs
@@ -430,7 +430,7 @@ impl cstore::CStore {
             use syntax_ext::proc_macro_impl::BangProcMacro;
 
             let client = proc_macro::bridge::client::Client::expand1(proc_macro::quote);
-            let ext = SyntaxExtension::ProcMacro {
+            let ext = SyntaxExtension::Bang {
                 expander: Box::new(BangProcMacro { client }),
                 allow_internal_unstable: Some(vec![sym::proc_macro_def_site].into()),
                 edition: data.root.edition,
diff --git a/src/librustc_plugin/registry.rs b/src/librustc_plugin/registry.rs
index 2ed6f868fa1ee..dd5e42684c427 100644
--- a/src/librustc_plugin/registry.rs
+++ b/src/librustc_plugin/registry.rs
@@ -4,8 +4,9 @@ use rustc::lint::{EarlyLintPassObject, LateLintPassObject, LintId, Lint};
 use rustc::session::Session;
 use rustc::util::nodemap::FxHashMap;
 
-use syntax::ext::base::{SyntaxExtension, NamedSyntaxExtension, NormalTT, IdentTT};
+use syntax::ext::base::{SyntaxExtension, NamedSyntaxExtension};
 use syntax::ext::base::MacroExpanderFn;
+use syntax::ext::hygiene::Transparency;
 use syntax::symbol::{Symbol, sym};
 use syntax::ast;
 use syntax::feature_gate::AttributeType;
@@ -84,47 +85,26 @@ impl<'a> Registry<'a> {
     /// Register a syntax extension of any kind.
     ///
     /// This is the most general hook into `libsyntax`'s expansion behavior.
-    pub fn register_syntax_extension(&mut self, name: ast::Name, extension: SyntaxExtension) {
+    pub fn register_syntax_extension(&mut self, name: ast::Name, mut extension: SyntaxExtension) {
         if name == sym::macro_rules {
             panic!("user-defined macros may not be named `macro_rules`");
         }
-        self.syntax_exts.push((name, match extension {
-            NormalTT {
-                expander,
-                def_info: _,
-                allow_internal_unstable,
-                allow_internal_unsafe,
-                local_inner_macros,
-                unstable_feature,
-                edition,
-            } => {
-                let nid = ast::CRATE_NODE_ID;
-                NormalTT {
-                    expander,
-                    def_info: Some((nid, self.krate_span)),
-                    allow_internal_unstable,
-                    allow_internal_unsafe,
-                    local_inner_macros,
-                    unstable_feature,
-                    edition,
-                }
-            }
-            IdentTT { expander, span: _, allow_internal_unstable } => {
-                IdentTT { expander, span: Some(self.krate_span), allow_internal_unstable }
-            }
-            _ => extension,
-        }));
+        if let SyntaxExtension::LegacyBang { def_info: ref mut def_info @ None, .. } = extension {
+            *def_info = Some((ast::CRATE_NODE_ID, self.krate_span));
+        }
+        self.syntax_exts.push((name, extension));
     }
 
     /// Register a macro of the usual kind.
     ///
     /// This is a convenience wrapper for `register_syntax_extension`.
-    /// It builds for you a `NormalTT` that calls `expander`,
+    /// It builds for you a `SyntaxExtension::LegacyBang` that calls `expander`,
     /// and also takes care of interning the macro's name.
     pub fn register_macro(&mut self, name: &str, expander: MacroExpanderFn) {
-        self.register_syntax_extension(Symbol::intern(name), NormalTT {
+        self.register_syntax_extension(Symbol::intern(name), SyntaxExtension::LegacyBang {
             expander: Box::new(expander),
             def_info: None,
+            transparency: Transparency::SemiTransparent,
             allow_internal_unstable: None,
             allow_internal_unsafe: false,
             local_inner_macros: false,
diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs
index 08ab5b8532522..2369bddf4f75f 100644
--- a/src/librustc_resolve/macros.rs
+++ b/src/librustc_resolve/macros.rs
@@ -242,8 +242,7 @@ impl<'a> base::Resolver for Resolver<'a> {
     fn check_unused_macros(&self) {
         for did in self.unused_macros.iter() {
             let id_span = match *self.macro_map[did] {
-                SyntaxExtension::NormalTT { def_info, .. } |
-                SyntaxExtension::DeclMacro { def_info, .. } => def_info,
+                SyntaxExtension::LegacyBang { def_info, .. } => def_info,
                 _ => None,
             };
             if let Some((id, span)) = id_span {
@@ -587,7 +586,7 @@ impl<'a> Resolver<'a> {
                         match self.resolve_macro_to_res(derive, MacroKind::Derive,
                                                         &parent_scope, true, force) {
                             Ok((_, ext)) => {
-                                if let SyntaxExtension::ProcMacroDerive(_, helpers, _) = &*ext {
+                                if let SyntaxExtension::Derive(_, helpers, _) = &*ext {
                                     if helpers.contains(&ident.name) {
                                         let binding =
                                             (Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper),
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 63d9f0920cc7b..5a46c9d440b5d 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -2155,6 +2155,17 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
         result_ty
     }
 
+    /// Returns the `DefId` of the constant parameter that the provided expression is a path to.
+    pub fn const_param_def_id(&self, expr: &hir::Expr) -> Option<DefId> {
+        match &expr.node {
+            ExprKind::Path(hir::QPath::Resolved(_, path)) => match path.res {
+                Res::Def(DefKind::ConstParam, did) => Some(did),
+                _ => None,
+            },
+            _ => None,
+        }
+    }
+
     pub fn ast_const_to_const(
         &self,
         ast_const: &hir::AnonConst,
@@ -2185,19 +2196,17 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o {
             }
         }
 
-        if let ExprKind::Path(ref qpath) = expr.node {
-            if let hir::QPath::Resolved(_, ref path) = qpath {
-                if let Res::Def(DefKind::ConstParam, def_id) = path.res {
-                    let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
-                    let item_id = tcx.hir().get_parent_node(node_id);
-                    let item_def_id = tcx.hir().local_def_id(item_id);
-                    let generics = tcx.generics_of(item_def_id);
-                    let index = generics.param_def_id_to_index[&tcx.hir().local_def_id(node_id)];
-                    let name = tcx.hir().name(node_id).as_interned_str();
-                    const_.val = ConstValue::Param(ty::ParamConst::new(index, name));
-                }
-            }
-        };
+        if let Some(def_id) = self.const_param_def_id(expr) {
+            // Find the name and index of the const parameter by indexing the generics of the
+            // parent item and construct a `ParamConst`.
+            let node_id = tcx.hir().as_local_node_id(def_id).unwrap();
+            let item_id = tcx.hir().get_parent_node(node_id);
+            let item_def_id = tcx.hir().local_def_id(item_id);
+            let generics = tcx.generics_of(item_def_id);
+            let index = generics.param_def_id_to_index[&tcx.hir().local_def_id(node_id)];
+            let name = tcx.hir().name(node_id).as_interned_str();
+            const_.val = ConstValue::Param(ty::ParamConst::new(index, name));
+        }
 
         tcx.mk_const(const_)
     }
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 0b558a20ed47e..209609ba3b8e0 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -2460,6 +2460,11 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         ty
     }
 
+    /// Returns the `DefId` of the constant parameter that the provided expression is a path to.
+    pub fn const_param_def_id(&self, hir_c: &hir::AnonConst) -> Option<DefId> {
+        AstConv::const_param_def_id(self, &self.tcx.hir().body(hir_c.body).value)
+    }
+
     pub fn to_const(&self, ast_c: &hir::AnonConst, ty: Ty<'tcx>) -> &'tcx ty::Const<'tcx> {
         AstConv::ast_const_to_const(self, ast_c, ty)
     }
@@ -4435,19 +4440,24 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
             }
             ExprKind::Repeat(ref element, ref count) => {
                 let count_def_id = tcx.hir().local_def_id_from_hir_id(count.hir_id);
-                let param_env = ty::ParamEnv::empty();
-                let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), count_def_id);
-                let instance = ty::Instance::resolve(
-                    tcx.global_tcx(),
-                    param_env,
-                    count_def_id,
-                    substs,
-                ).unwrap();
-                let global_id = GlobalId {
-                    instance,
-                    promoted: None
+                let count = if self.const_param_def_id(count).is_some() {
+                    Ok(self.to_const(count, self.tcx.type_of(count_def_id)))
+                } else {
+                    let param_env = ty::ParamEnv::empty();
+                    let substs = InternalSubsts::identity_for_item(tcx.global_tcx(), count_def_id);
+                    let instance = ty::Instance::resolve(
+                        tcx.global_tcx(),
+                        param_env,
+                        count_def_id,
+                        substs,
+                    ).unwrap();
+                    let global_id = GlobalId {
+                        instance,
+                        promoted: None
+                    };
+
+                    tcx.const_eval(param_env.and(global_id))
                 };
-                let count = tcx.const_eval(param_env.and(global_id));
 
                 let uty = match expected {
                     ExpectHasType(uty) => {
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 15108a7dbb91c..5a5540e7e3855 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -471,7 +471,7 @@ fn build_macro(cx: &DocContext<'_>, did: DefId, name: ast::Name) -> clean::ItemE
         }
         LoadedMacro::ProcMacro(ext) => {
             let helpers = match &*ext {
-                &SyntaxExtension::ProcMacroDerive(_, ref syms, ..) => { syms.clean(cx) }
+                &SyntaxExtension::Derive(_, ref syms, ..) => { syms.clean(cx) }
                 _ => Vec::new(),
             };
 
diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index 860ea18a58ad0..7fbfc3e1fc0f4 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
@@ -433,7 +433,7 @@ fn macro_resolve(cx: &DocContext<'_>, path_str: &str) -> Option<Res> {
             if let Res::Def(DefKind::Macro(MacroKind::ProcMacroStub), _) = res {
                 // skip proc-macro stubs, they'll cause `get_macro` to crash
             } else {
-                if let SyntaxExtension::DeclMacro { .. } = *resolver.get_macro(res) {
+                if let SyntaxExtension::LegacyBang { .. } = *resolver.get_macro(res) {
                     return Some(res.map_id(|_| panic!("unexpected id")));
                 }
             }
diff --git a/src/libstd/Cargo.toml b/src/libstd/Cargo.toml
index 30e23f1007f20..a170dae2b08ca 100644
--- a/src/libstd/Cargo.toml
+++ b/src/libstd/Cargo.toml
@@ -15,6 +15,7 @@ crate-type = ["dylib", "rlib"]
 
 [dependencies]
 alloc = { path = "../liballoc" }
+cfg-if = "0.1.8"
 panic_unwind = { path = "../libpanic_unwind", optional = true }
 panic_abort = { path = "../libpanic_abort" }
 core = { path = "../libcore" }
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index a3356e6be2c3f..e0ffc9ba92f11 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -336,6 +336,12 @@ extern crate libc;
 #[allow(unused_extern_crates)]
 extern crate unwind;
 
+// Only needed for now for the `std_detect` module until that crate changes to
+// use `cfg_if::cfg_if!`
+#[macro_use]
+#[cfg(not(test))]
+extern crate cfg_if;
+
 // During testing, this crate is not actually the "real" std library, but rather
 // it links to the real std library, which was compiled from this same source
 // code. So any lang items std defines are conditionally excluded (or else they
diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs
index ef7179f0b6f90..92b9a16f3e316 100644
--- a/src/libstd/macros.rs
+++ b/src/libstd/macros.rs
@@ -896,39 +896,3 @@ mod builtin {
         ($cond:expr, $($arg:tt)+) => ({ /* compiler built-in */ });
     }
 }
-
-/// Defines `#[cfg]` if-else statements.
-///
-/// This is similar to the `if/elif` C preprocessor macro by allowing definition
-/// of a cascade of `#[cfg]` cases, emitting the implementation which matches
-/// first.
-///
-/// This allows you to conveniently provide a long list `#[cfg]`'d blocks of code
-/// without having to rewrite each clause multiple times.
-macro_rules! cfg_if {
-    ($(
-        if #[cfg($($meta:meta),*)] { $($it:item)* }
-    ) else * else {
-        $($it2:item)*
-    }) => {
-        __cfg_if_items! {
-            () ;
-            $( ( ($($meta),*) ($($it)*) ), )*
-            ( () ($($it2)*) ),
-        }
-    }
-}
-
-macro_rules! __cfg_if_items {
-    (($($not:meta,)*) ; ) => {};
-    (($($not:meta,)*) ; ( ($($m:meta),*) ($($it:item)*) ), $($rest:tt)*) => {
-        __cfg_if_apply! { cfg(all(not(any($($not),*)), $($m,)*)), $($it)* }
-        __cfg_if_items! { ($($not,)* $($m,)*) ; $($rest)* }
-    }
-}
-
-macro_rules! __cfg_if_apply {
-    ($m:meta, $($it:item)*) => {
-        $(#[$m] $it)*
-    }
-}
diff --git a/src/libstd/os/mod.rs b/src/libstd/os/mod.rs
index 44cbc180b8b01..94e8b7805cf93 100644
--- a/src/libstd/os/mod.rs
+++ b/src/libstd/os/mod.rs
@@ -3,7 +3,7 @@
 #![stable(feature = "os", since = "1.0.0")]
 #![allow(missing_docs, nonstandard_style, missing_debug_implementations)]
 
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(rustdoc)] {
 
         // When documenting libstd we want to show unix/windows/linux modules as
diff --git a/src/libstd/sys/mod.rs b/src/libstd/sys/mod.rs
index 3f3cedc53b729..21360e2e0f028 100644
--- a/src/libstd/sys/mod.rs
+++ b/src/libstd/sys/mod.rs
@@ -22,7 +22,7 @@
 
 #![allow(missing_debug_implementations)]
 
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(unix)] {
         mod unix;
         pub use self::unix::*;
@@ -54,7 +54,7 @@ cfg_if! {
 // Windows when we're compiling for Linux.
 
 #[cfg(rustdoc)]
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(any(unix, target_os = "redox"))] {
         // On unix we'll document what's already available
         #[stable(feature = "rust1", since = "1.0.0")]
@@ -77,7 +77,7 @@ cfg_if! {
 }
 
 #[cfg(rustdoc)]
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(windows)] {
         // On windows we'll just be documenting what's already available
         #[allow(missing_docs)]
diff --git a/src/libstd/sys/wasm/mod.rs b/src/libstd/sys/wasm/mod.rs
index 9ea8bd1653851..7d157709eb6bf 100644
--- a/src/libstd/sys/wasm/mod.rs
+++ b/src/libstd/sys/wasm/mod.rs
@@ -40,7 +40,7 @@ pub mod stdio;
 
 pub use crate::sys_common::os_str_bytes as os_str;
 
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(target_feature = "atomics")] {
         #[path = "condvar_atomics.rs"]
         pub mod condvar;
diff --git a/src/libstd/sys/wasm/thread.rs b/src/libstd/sys/wasm/thread.rs
index 1dc786cd5d7b6..61b4003cd3d14 100644
--- a/src/libstd/sys/wasm/thread.rs
+++ b/src/libstd/sys/wasm/thread.rs
@@ -59,7 +59,7 @@ pub mod guard {
     pub unsafe fn init() -> Option<Guard> { None }
 }
 
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(all(target_feature = "atomics", feature = "wasm-bindgen-threads"))] {
         #[link(wasm_import_module = "__wbindgen_thread_xform__")]
         extern {
diff --git a/src/libstd/sys_common/mod.rs b/src/libstd/sys_common/mod.rs
index c4daedefd8e6d..13a59f66c5c2f 100644
--- a/src/libstd/sys_common/mod.rs
+++ b/src/libstd/sys_common/mod.rs
@@ -65,7 +65,7 @@ pub mod bytestring;
 pub mod process;
 pub mod fs;
 
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(any(target_os = "cloudabi",
                  target_os = "l4re",
                  target_os = "redox",
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 61c736662c71e..38b7dee40c447 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -1,6 +1,4 @@
-pub use SyntaxExtension::*;
-
-use crate::ast::{self, Attribute, Name, PatKind, MetaItem};
+use crate::ast::{self, Attribute, Name, PatKind};
 use crate::attr::HasAttrs;
 use crate::source_map::{SourceMap, Spanned, respan};
 use crate::edition::Edition;
@@ -137,29 +135,6 @@ impl Annotatable {
     }
 }
 
-// A more flexible ItemDecorator.
-pub trait MultiItemDecorator {
-    fn expand(&self,
-              ecx: &mut ExtCtxt<'_>,
-              sp: Span,
-              meta_item: &ast::MetaItem,
-              item: &Annotatable,
-              push: &mut dyn FnMut(Annotatable));
-}
-
-impl<F> MultiItemDecorator for F
-    where F : Fn(&mut ExtCtxt<'_>, Span, &ast::MetaItem, &Annotatable, &mut dyn FnMut(Annotatable))
-{
-    fn expand(&self,
-              ecx: &mut ExtCtxt<'_>,
-              sp: Span,
-              meta_item: &ast::MetaItem,
-              item: &Annotatable,
-              push: &mut dyn FnMut(Annotatable)) {
-        (*self)(ecx, sp, meta_item, item, push)
-    }
-}
-
 // `meta_item` is the annotation, and `item` is the item being modified.
 // FIXME Decorators should follow the same pattern too.
 pub trait MultiItemModifier {
@@ -288,34 +263,6 @@ impl<F> TTMacroExpander for F
     }
 }
 
-pub trait IdentMacroExpander {
-    fn expand<'cx>(&self,
-                   cx: &'cx mut ExtCtxt<'_>,
-                   sp: Span,
-                   ident: ast::Ident,
-                   token_tree: Vec<tokenstream::TokenTree>)
-                   -> Box<dyn MacResult+'cx>;
-}
-
-pub type IdentMacroExpanderFn =
-    for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, ast::Ident, Vec<tokenstream::TokenTree>)
-                -> Box<dyn MacResult+'cx>;
-
-impl<F> IdentMacroExpander for F
-    where F : for<'cx> Fn(&'cx mut ExtCtxt<'_>, Span, ast::Ident,
-                          Vec<tokenstream::TokenTree>) -> Box<dyn MacResult+'cx>
-{
-    fn expand<'cx>(&self,
-                   cx: &'cx mut ExtCtxt<'_>,
-                   sp: Span,
-                   ident: ast::Ident,
-                   token_tree: Vec<tokenstream::TokenTree>)
-                   -> Box<dyn MacResult+'cx>
-    {
-        (*self)(cx, sp, ident, token_tree)
-    }
-}
-
 // Use a macro because forwarding to a simple function has type system issues
 macro_rules! make_stmts_default {
     ($me:expr) => {
@@ -570,9 +517,6 @@ impl MacResult for DummyResult {
     }
 }
 
-pub type BuiltinDeriveFn =
-    for<'cx> fn(&'cx mut ExtCtxt<'_>, Span, &MetaItem, &Annotatable, &mut dyn FnMut(Annotatable));
-
 /// Represents different kinds of macro invocations that can be resolved.
 #[derive(Clone, Copy, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum MacroKind {
@@ -606,129 +550,116 @@ impl MacroKind {
 
 /// An enum representing the different kinds of syntax extensions.
 pub enum SyntaxExtension {
-    /// A trivial "extension" that does nothing, only keeps the attribute and marks it as known.
-    NonMacroAttr { mark_used: bool },
-
-    /// A syntax extension that is attached to an item and creates new items
-    /// based upon it.
-    ///
-    /// `#[derive(...)]` is a `MultiItemDecorator`.
-    ///
-    /// Prefer ProcMacro or MultiModifier since they are more flexible.
-    MultiDecorator(Box<dyn MultiItemDecorator + sync::Sync + sync::Send>),
-
-    /// A syntax extension that is attached to an item and modifies it
-    /// in-place. Also allows decoration, i.e., creating new items.
-    MultiModifier(Box<dyn MultiItemModifier + sync::Sync + sync::Send>),
-
-    /// A function-like procedural macro. TokenStream -> TokenStream.
-    ProcMacro {
+    /// A token-based function-like macro.
+    Bang {
+        /// An expander with signature TokenStream -> TokenStream.
         expander: Box<dyn ProcMacro + sync::Sync + sync::Send>,
-        /// Whitelist of unstable features that are treated as stable inside this macro
+        /// Whitelist of unstable features that are treated as stable inside this macro.
         allow_internal_unstable: Option<Lrc<[Symbol]>>,
+        /// Edition of the crate in which this macro is defined.
         edition: Edition,
     },
 
-    /// An attribute-like procedural macro. TokenStream, TokenStream -> TokenStream.
-    /// The first TokenSteam is the attribute, the second is the annotated item.
-    /// Allows modification of the input items and adding new items, similar to
-    /// MultiModifier, but uses TokenStreams, rather than AST nodes.
-    AttrProcMacro(Box<dyn AttrProcMacro + sync::Sync + sync::Send>, Edition),
-
-    /// A normal, function-like syntax extension.
-    ///
-    /// `bytes!` is a `NormalTT`.
-    NormalTT {
+    /// An AST-based function-like macro.
+    LegacyBang {
+        /// An expander with signature TokenStream -> AST.
         expander: Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
+        /// Some info about the macro's definition point.
         def_info: Option<(ast::NodeId, Span)>,
-        /// Whether the contents of the macro can
-        /// directly use `#[unstable]` things.
-        ///
-        /// Only allows things that require a feature gate in the given whitelist
+        /// Hygienic properties of identifiers produced by this macro.
+        transparency: Transparency,
+        /// Whitelist of unstable features that are treated as stable inside this macro.
         allow_internal_unstable: Option<Lrc<[Symbol]>>,
-        /// Whether the contents of the macro can use `unsafe`
-        /// without triggering the `unsafe_code` lint.
+        /// Suppresses the `unsafe_code` lint for code produced by this macro.
         allow_internal_unsafe: bool,
-        /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`)
-        /// for a given macro.
+        /// Enables the macro helper hack (`ident!(...)` -> `$crate::ident!(...)`) for this macro.
         local_inner_macros: bool,
-        /// The macro's feature name if it is unstable, and the stability feature
+        /// The macro's feature name and tracking issue number if it is unstable.
         unstable_feature: Option<(Symbol, u32)>,
-        /// Edition of the crate in which the macro is defined
+        /// Edition of the crate in which this macro is defined.
         edition: Edition,
     },
 
-    /// A function-like syntax extension that has an extra ident before
-    /// the block.
-    IdentTT {
-        expander: Box<dyn IdentMacroExpander + sync::Sync + sync::Send>,
-        span: Option<Span>,
-        allow_internal_unstable: Option<Lrc<[Symbol]>>,
+    /// A token-based attribute macro.
+    Attr(
+        /// An expander with signature (TokenStream, TokenStream) -> TokenStream.
+        /// The first TokenSteam is the attribute itself, the second is the annotated item.
+        /// The produced TokenSteam replaces the input TokenSteam.
+        Box<dyn AttrProcMacro + sync::Sync + sync::Send>,
+        /// Edition of the crate in which this macro is defined.
+        Edition,
+    ),
+
+    /// An AST-based attribute macro.
+    LegacyAttr(
+        /// An expander with signature (AST, AST) -> AST.
+        /// The first AST fragment is the attribute itself, the second is the annotated item.
+        /// The produced AST fragment replaces the input AST fragment.
+        Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
+    ),
+
+    /// A trivial attribute "macro" that does nothing,
+    /// only keeps the attribute and marks it as known.
+    NonMacroAttr {
+        /// Suppresses the `unused_attributes` lint for this attribute.
+        mark_used: bool,
     },
 
-    /// An attribute-like procedural macro. TokenStream -> TokenStream.
-    /// The input is the annotated item.
-    /// Allows generating code to implement a Trait for a given struct
-    /// or enum item.
-    ProcMacroDerive(Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
-                    Vec<Symbol> /* inert attribute names */, Edition),
-
-    /// An attribute-like procedural macro that derives a builtin trait.
-    BuiltinDerive(BuiltinDeriveFn),
-
-    /// A declarative macro, e.g., `macro m() {}`.
-    DeclMacro {
-        expander: Box<dyn TTMacroExpander + sync::Sync + sync::Send>,
-        def_info: Option<(ast::NodeId, Span)>,
-        is_transparent: bool,
-        edition: Edition,
-    }
+    /// A token-based derive macro.
+    Derive(
+        /// An expander with signature TokenStream -> TokenStream (not yet).
+        /// The produced TokenSteam is appended to the input TokenSteam.
+        Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
+        /// Names of helper attributes registered by this macro.
+        Vec<Symbol>,
+        /// Edition of the crate in which this macro is defined.
+        Edition,
+    ),
+
+    /// An AST-based derive macro.
+    LegacyDerive(
+        /// An expander with signature AST -> AST.
+        /// The produced AST fragment is appended to the input AST fragment.
+        Box<dyn MultiItemModifier + sync::Sync + sync::Send>,
+    ),
 }
 
 impl SyntaxExtension {
     /// Returns which kind of macro calls this syntax extension.
     pub fn kind(&self) -> MacroKind {
         match *self {
-            SyntaxExtension::DeclMacro { .. } |
-            SyntaxExtension::NormalTT { .. } |
-            SyntaxExtension::IdentTT { .. } |
-            SyntaxExtension::ProcMacro { .. } =>
-                MacroKind::Bang,
-            SyntaxExtension::NonMacroAttr { .. } |
-            SyntaxExtension::MultiDecorator(..) |
-            SyntaxExtension::MultiModifier(..) |
-            SyntaxExtension::AttrProcMacro(..) =>
-                MacroKind::Attr,
-            SyntaxExtension::ProcMacroDerive(..) |
-            SyntaxExtension::BuiltinDerive(..) =>
-                MacroKind::Derive,
+            SyntaxExtension::Bang { .. } |
+            SyntaxExtension::LegacyBang { .. } => MacroKind::Bang,
+            SyntaxExtension::Attr(..) |
+            SyntaxExtension::LegacyAttr(..) |
+            SyntaxExtension::NonMacroAttr { .. } => MacroKind::Attr,
+            SyntaxExtension::Derive(..) |
+            SyntaxExtension::LegacyDerive(..) => MacroKind::Derive,
         }
     }
 
     pub fn default_transparency(&self) -> Transparency {
         match *self {
-            SyntaxExtension::ProcMacro { .. } |
-            SyntaxExtension::AttrProcMacro(..) |
-            SyntaxExtension::ProcMacroDerive(..) |
-            SyntaxExtension::DeclMacro { is_transparent: false, .. } => Transparency::Opaque,
-            SyntaxExtension::DeclMacro { is_transparent: true, .. } => Transparency::Transparent,
-            _ => Transparency::SemiTransparent,
+            SyntaxExtension::LegacyBang { transparency, .. } => transparency,
+            SyntaxExtension::Bang { .. } |
+            SyntaxExtension::Attr(..) |
+            SyntaxExtension::Derive(..) |
+            SyntaxExtension::NonMacroAttr { .. } => Transparency::Opaque,
+            SyntaxExtension::LegacyAttr(..) |
+            SyntaxExtension::LegacyDerive(..) => Transparency::SemiTransparent,
         }
     }
 
     pub fn edition(&self, default_edition: Edition) -> Edition {
         match *self {
-            SyntaxExtension::NormalTT { edition, .. } |
-            SyntaxExtension::DeclMacro { edition, .. } |
-            SyntaxExtension::ProcMacro { edition, .. } |
-            SyntaxExtension::AttrProcMacro(.., edition) |
-            SyntaxExtension::ProcMacroDerive(.., edition) => edition,
+            SyntaxExtension::Bang { edition, .. } |
+            SyntaxExtension::LegacyBang { edition, .. } |
+            SyntaxExtension::Attr(.., edition) |
+            SyntaxExtension::Derive(.., edition) => edition,
             // Unstable legacy stuff
             SyntaxExtension::NonMacroAttr { .. } |
-            SyntaxExtension::IdentTT { .. } |
-            SyntaxExtension::MultiDecorator(..) |
-            SyntaxExtension::MultiModifier(..) |
-            SyntaxExtension::BuiltinDerive(..) => default_edition,
+            SyntaxExtension::LegacyAttr(..) |
+            SyntaxExtension::LegacyDerive(..) => default_edition,
         }
     }
 }
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 9960539555332..084d4fd382017 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -389,7 +389,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                         let item = match self.cx.resolver.resolve_macro_path(
                                 path, MacroKind::Derive, Mark::root(), Vec::new(), false) {
                             Ok(ext) => match *ext {
-                                BuiltinDerive(..) => item_with_markers.clone(),
+                                SyntaxExtension::LegacyDerive(..) => item_with_markers.clone(),
                                 _ => item.clone(),
                             },
                             _ => item.clone(),
@@ -548,7 +548,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             _ => unreachable!(),
         };
 
-        if let NonMacroAttr { mark_used: false } = *ext {} else {
+        if let SyntaxExtension::NonMacroAttr { mark_used: false } = *ext {} else {
             // Macro attrs are always used when expanded,
             // non-macro attrs are considered used when the field says so.
             attr::mark_used(&attr);
@@ -564,26 +564,18 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         });
 
         match *ext {
-            NonMacroAttr { .. } => {
+            SyntaxExtension::NonMacroAttr { .. } => {
                 attr::mark_known(&attr);
                 item.visit_attrs(|attrs| attrs.push(attr));
                 Some(invoc.fragment_kind.expect_from_annotatables(iter::once(item)))
             }
-            MultiModifier(ref mac) => {
+            SyntaxExtension::LegacyAttr(ref mac) => {
                 let meta = attr.parse_meta(self.cx.parse_sess)
                                .map_err(|mut e| { e.emit(); }).ok()?;
                 let item = mac.expand(self.cx, attr.span, &meta, item);
                 Some(invoc.fragment_kind.expect_from_annotatables(item))
             }
-            MultiDecorator(ref mac) => {
-                let mut items = Vec::new();
-                let meta = attr.parse_meta(self.cx.parse_sess)
-                               .expect("derive meta should already have been parsed");
-                mac.expand(self.cx, attr.span, &meta, &item, &mut |item| items.push(item));
-                items.push(item);
-                Some(invoc.fragment_kind.expect_from_annotatables(items))
-            }
-            AttrProcMacro(ref mac, ..) => {
+            SyntaxExtension::Attr(ref mac, ..) => {
                 self.gate_proc_macro_attr_item(attr.span, &item);
                 let item_tok = TokenTree::token(token::Interpolated(Lrc::new(match item {
                     Annotatable::Item(item) => token::NtItem(item),
@@ -600,7 +592,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 self.gate_proc_macro_expansion(attr.span, &res);
                 res
             }
-            ProcMacroDerive(..) | BuiltinDerive(..) => {
+            SyntaxExtension::Derive(..) | SyntaxExtension::LegacyDerive(..) => {
                 self.cx.span_err(attr.span, &format!("`{}` is a derive macro", attr.path));
                 self.cx.trace_macros_diag();
                 invoc.fragment_kind.dummy(attr.span)
@@ -755,17 +747,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
         };
 
         let opt_expanded = match *ext {
-            DeclMacro { ref expander, def_info, edition, .. } => {
-                if let Err(dummy_span) = validate_and_set_expn_info(self, def_info.map(|(_, s)| s),
-                                                                    None, false, false, None,
-                                                                    edition) {
-                    dummy_span
-                } else {
-                    kind.make_from(expander.expand(self.cx, span, mac.node.stream(), None))
-                }
-            }
-
-            NormalTT {
+            SyntaxExtension::LegacyBang {
                 ref expander,
                 def_info,
                 ref allow_internal_unstable,
@@ -773,6 +755,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 local_inner_macros,
                 unstable_feature,
                 edition,
+                ..
             } => {
                 if let Err(dummy_span) = validate_and_set_expn_info(self, def_info.map(|(_, s)| s),
                                                                     allow_internal_unstable.clone(),
@@ -791,43 +774,22 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                 }
             }
 
-            IdentTT { ref expander, span: tt_span, ref allow_internal_unstable } => {
-                if ident.name == kw::Invalid {
-                    self.cx.span_err(path.span,
-                                    &format!("macro {}! expects an ident argument", path));
-                    self.cx.trace_macros_diag();
-                    kind.dummy(span)
-                } else {
-                    invoc.expansion_data.mark.set_expn_info(ExpnInfo {
-                        call_site: span,
-                        def_site: tt_span,
-                        format: macro_bang_format(path),
-                        allow_internal_unstable: allow_internal_unstable.clone(),
-                        allow_internal_unsafe: false,
-                        local_inner_macros: false,
-                        edition: self.cx.parse_sess.edition,
-                    });
-
-                    let input: Vec<_> = mac.node.stream().into_trees().collect();
-                    kind.make_from(expander.expand(self.cx, span, ident, input))
-                }
-            }
-
-            MultiDecorator(..) | MultiModifier(..) |
-            AttrProcMacro(..) | SyntaxExtension::NonMacroAttr { .. } => {
+            SyntaxExtension::Attr(..) |
+            SyntaxExtension::LegacyAttr(..) |
+            SyntaxExtension::NonMacroAttr { .. } => {
                 self.cx.span_err(path.span,
                                  &format!("`{}` can only be used in attributes", path));
                 self.cx.trace_macros_diag();
                 kind.dummy(span)
             }
 
-            ProcMacroDerive(..) | BuiltinDerive(..) => {
+            SyntaxExtension::Derive(..) | SyntaxExtension::LegacyDerive(..) => {
                 self.cx.span_err(path.span, &format!("`{}` is a derive macro", path));
                 self.cx.trace_macros_diag();
                 kind.dummy(span)
             }
 
-            SyntaxExtension::ProcMacro { ref expander, ref allow_internal_unstable, edition } => {
+            SyntaxExtension::Bang { ref expander, ref allow_internal_unstable, edition } => {
                 if ident.name != kw::Invalid {
                     let msg =
                         format!("macro {}! expects no ident argument, given '{}'", path, ident);
@@ -924,29 +886,29 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
             edition: ext.edition(self.cx.parse_sess.edition),
         };
 
-        match *ext {
-            ProcMacroDerive(ref ext, ..) => {
-                invoc.expansion_data.mark.set_expn_info(expn_info);
-                let span = span.with_ctxt(self.cx.backtrace());
-                let dummy = ast::MetaItem { // FIXME(jseyfried) avoid this
-                    path: Path::from_ident(Ident::invalid()),
-                    span: DUMMY_SP,
-                    node: ast::MetaItemKind::Word,
+        match ext {
+            SyntaxExtension::Derive(expander, ..) | SyntaxExtension::LegacyDerive(expander) => {
+                let meta = match ext {
+                    SyntaxExtension::Derive(..) => ast::MetaItem { // FIXME(jseyfried) avoid this
+                        path: Path::from_ident(Ident::invalid()),
+                        span: DUMMY_SP,
+                        node: ast::MetaItemKind::Word,
+                    },
+                    _ => {
+                        expn_info.allow_internal_unstable = Some(vec![
+                            sym::rustc_attrs,
+                            Symbol::intern("derive_clone_copy"),
+                            Symbol::intern("derive_eq"),
+                            // RustcDeserialize and RustcSerialize
+                            Symbol::intern("libstd_sys_internals"),
+                        ].into());
+                        attr.meta()?
+                    }
                 };
-                let items = ext.expand(self.cx, span, &dummy, item);
-                Some(invoc.fragment_kind.expect_from_annotatables(items))
-            }
-            BuiltinDerive(func) => {
-                expn_info.allow_internal_unstable = Some(vec![
-                    sym::rustc_attrs,
-                    Symbol::intern("derive_clone_copy"),
-                    Symbol::intern("derive_eq"),
-                    Symbol::intern("libstd_sys_internals"), // RustcDeserialize and RustcSerialize
-                ].into());
+
                 invoc.expansion_data.mark.set_expn_info(expn_info);
                 let span = span.with_ctxt(self.cx.backtrace());
-                let mut items = Vec::new();
-                func(self.cx, span, &attr.meta()?, &item, &mut |a| items.push(a));
+                let items = expander.expand(self.cx, span, &meta, item);
                 Some(invoc.fragment_kind.expect_from_annotatables(items))
             }
             _ => {
diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 6f82f5094651e..5dbf21867afa6 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -1,8 +1,8 @@
 use crate::{ast, attr};
 use crate::edition::Edition;
-use crate::ext::base::{DummyResult, ExtCtxt, MacResult, SyntaxExtension};
-use crate::ext::base::{NormalTT, TTMacroExpander};
+use crate::ext::base::{DummyResult, ExtCtxt, MacResult, SyntaxExtension, TTMacroExpander};
 use crate::ext::expand::{AstFragment, AstFragmentKind};
+use crate::ext::hygiene::Transparency;
 use crate::ext::tt::macro_parser::{Success, Error, Failure};
 use crate::ext::tt::macro_parser::{MatchedSeq, MatchedNonterminal};
 use crate::ext::tt::macro_parser::{parse, parse_failure_msg};
@@ -374,65 +374,65 @@ pub fn compile(
         valid,
     });
 
-    if body.legacy {
-        let allow_internal_unstable = attr::find_by_name(&def.attrs, sym::allow_internal_unstable)
-            .map(|attr| attr
-                .meta_item_list()
-                .map(|list| list.iter()
-                    .filter_map(|it| {
-                        let name = it.ident().map(|ident| ident.name);
-                        if name.is_none() {
-                            sess.span_diagnostic.span_err(it.span(),
-                                "allow internal unstable expects feature names")
-                        }
-                        name
-                    })
-                    .collect::<Vec<Symbol>>().into()
-                )
-                .unwrap_or_else(|| {
-                    sess.span_diagnostic.span_warn(
-                        attr.span, "allow_internal_unstable expects list of feature names. In the \
-                        future this will become a hard error. Please use `allow_internal_unstable(\
-                        foo, bar)` to only allow the `foo` and `bar` features",
-                    );
-                    vec![sym::allow_internal_unstable_backcompat_hack].into()
+    let transparency = if attr::contains_name(&def.attrs, sym::rustc_transparent_macro) {
+        Transparency::Transparent
+    } else if body.legacy {
+        Transparency::SemiTransparent
+    } else {
+        Transparency::Opaque
+    };
+
+    let allow_internal_unstable = attr::find_by_name(&def.attrs, sym::allow_internal_unstable)
+        .map(|attr| attr
+            .meta_item_list()
+            .map(|list| list.iter()
+                .filter_map(|it| {
+                    let name = it.ident().map(|ident| ident.name);
+                    if name.is_none() {
+                        sess.span_diagnostic.span_err(it.span(),
+                            "allow internal unstable expects feature names")
+                    }
+                    name
                 })
-            );
-        let allow_internal_unsafe = attr::contains_name(&def.attrs, sym::allow_internal_unsafe);
-        let mut local_inner_macros = false;
-        if let Some(macro_export) = attr::find_by_name(&def.attrs, sym::macro_export) {
-            if let Some(l) = macro_export.meta_item_list() {
-                local_inner_macros = attr::list_contains_name(&l, sym::local_inner_macros);
-            }
-        }
+                .collect::<Vec<Symbol>>().into()
+            )
+            .unwrap_or_else(|| {
+                sess.span_diagnostic.span_warn(
+                    attr.span, "allow_internal_unstable expects list of feature names. In the \
+                    future this will become a hard error. Please use `allow_internal_unstable(\
+                    foo, bar)` to only allow the `foo` and `bar` features",
+                );
+                vec![sym::allow_internal_unstable_backcompat_hack].into()
+            })
+        );
 
-        let unstable_feature = attr::find_stability(&sess,
-                                                    &def.attrs, def.span).and_then(|stability| {
-            if let attr::StabilityLevel::Unstable { issue, .. } = stability.level {
-                Some((stability.feature, issue))
-            } else {
-                None
-            }
-        });
-
-        NormalTT {
-            expander,
-            def_info: Some((def.id, def.span)),
-            allow_internal_unstable,
-            allow_internal_unsafe,
-            local_inner_macros,
-            unstable_feature,
-            edition,
+    let allow_internal_unsafe = attr::contains_name(&def.attrs, sym::allow_internal_unsafe);
+
+    let mut local_inner_macros = false;
+    if let Some(macro_export) = attr::find_by_name(&def.attrs, sym::macro_export) {
+        if let Some(l) = macro_export.meta_item_list() {
+            local_inner_macros = attr::list_contains_name(&l, sym::local_inner_macros);
         }
-    } else {
-        let is_transparent = attr::contains_name(&def.attrs, sym::rustc_transparent_macro);
+    }
 
-        SyntaxExtension::DeclMacro {
-            expander,
-            def_info: Some((def.id, def.span)),
-            is_transparent,
-            edition,
+    let unstable_feature = attr::find_stability(&sess,
+                                                &def.attrs, def.span).and_then(|stability| {
+        if let attr::StabilityLevel::Unstable { issue, .. } = stability.level {
+            Some((stability.feature, issue))
+        } else {
+            None
         }
+    });
+
+    SyntaxExtension::LegacyBang {
+        expander,
+        def_info: Some((def.id, def.span)),
+        transparency,
+        allow_internal_unstable,
+        allow_internal_unsafe,
+        local_inner_macros,
+        unstable_feature,
+        edition,
     }
 }
 
diff --git a/src/libsyntax_ext/deriving/mod.rs b/src/libsyntax_ext/deriving/mod.rs
index ac41f30e6b39f..cf54eacc3d46c 100644
--- a/src/libsyntax_ext/deriving/mod.rs
+++ b/src/libsyntax_ext/deriving/mod.rs
@@ -1,8 +1,8 @@
 //! The compiler code necessary to implement the `#[derive]` extensions.
 
 use rustc_data_structures::sync::Lrc;
-use syntax::ast;
-use syntax::ext::base::{Annotatable, ExtCtxt, SyntaxExtension, Resolver};
+use syntax::ast::{self, MetaItem};
+use syntax::ext::base::{Annotatable, ExtCtxt, SyntaxExtension, Resolver, MultiItemModifier};
 use syntax::ext::build::AstBuilder;
 use syntax::ext::hygiene::{Mark, SyntaxContext};
 use syntax::ptr::P;
@@ -39,9 +39,25 @@ pub mod partial_ord;
 #[path="cmp/ord.rs"]
 pub mod ord;
 
-
 pub mod generic;
 
+struct BuiltinDerive(
+    fn(&mut ExtCtxt<'_>, Span, &MetaItem, &Annotatable, &mut dyn FnMut(Annotatable))
+);
+
+impl MultiItemModifier for BuiltinDerive {
+    fn expand(&self,
+              ecx: &mut ExtCtxt<'_>,
+              span: Span,
+              meta_item: &MetaItem,
+              item: Annotatable)
+              -> Vec<Annotatable> {
+        let mut items = Vec::new();
+        (self.0)(ecx, span, meta_item, &item, &mut |a| items.push(a));
+        items
+    }
+}
+
 macro_rules! derive_traits {
     ($( $name:expr => $func:path, )+) => {
         pub fn is_builtin_trait(name: ast::Name) -> bool {
@@ -55,7 +71,7 @@ macro_rules! derive_traits {
             $(
                 resolver.add_builtin(
                     ast::Ident::with_empty_ctxt(Symbol::intern($name)),
-                    Lrc::new(SyntaxExtension::BuiltinDerive($func))
+                    Lrc::new(SyntaxExtension::LegacyDerive(Box::new(BuiltinDerive($func))))
                 );
             )*
         }
diff --git a/src/libsyntax_ext/lib.rs b/src/libsyntax_ext/lib.rs
index fc00154427501..7c4085aa09653 100644
--- a/src/libsyntax_ext/lib.rs
+++ b/src/libsyntax_ext/lib.rs
@@ -41,7 +41,9 @@ pub mod proc_macro_impl;
 
 use rustc_data_structures::sync::Lrc;
 use syntax::ast;
-use syntax::ext::base::{MacroExpanderFn, NormalTT, NamedSyntaxExtension, MultiModifier};
+
+use syntax::ext::base::{MacroExpanderFn, NamedSyntaxExtension, SyntaxExtension};
+use syntax::ext::hygiene::Transparency;
 use syntax::edition::Edition;
 use syntax::symbol::{sym, Symbol};
 
@@ -56,9 +58,10 @@ pub fn register_builtins(resolver: &mut dyn syntax::ext::base::Resolver,
     macro_rules! register {
         ($( $name:ident: $f:expr, )*) => { $(
             register(Symbol::intern(stringify!($name)),
-                     NormalTT {
+                     SyntaxExtension::LegacyBang {
                         expander: Box::new($f as MacroExpanderFn),
                         def_info: None,
+                        transparency: Transparency::SemiTransparent,
                         allow_internal_unstable: None,
                         allow_internal_unsafe: false,
                         local_inner_macros: false,
@@ -93,15 +96,16 @@ pub fn register_builtins(resolver: &mut dyn syntax::ext::base::Resolver,
         assert: assert::expand_assert,
     }
 
-    register(sym::test_case, MultiModifier(Box::new(test_case::expand)));
-    register(sym::test, MultiModifier(Box::new(test::expand_test)));
-    register(sym::bench, MultiModifier(Box::new(test::expand_bench)));
+    register(sym::test_case, SyntaxExtension::LegacyAttr(Box::new(test_case::expand)));
+    register(sym::test, SyntaxExtension::LegacyAttr(Box::new(test::expand_test)));
+    register(sym::bench, SyntaxExtension::LegacyAttr(Box::new(test::expand_bench)));
 
     // format_args uses `unstable` things internally.
     register(Symbol::intern("format_args"),
-             NormalTT {
+             SyntaxExtension::LegacyBang {
                 expander: Box::new(format::expand_format_args),
                 def_info: None,
+                transparency: Transparency::SemiTransparent,
                 allow_internal_unstable: Some(vec![sym::fmt_internals].into()),
                 allow_internal_unsafe: false,
                 local_inner_macros: false,
@@ -109,9 +113,10 @@ pub fn register_builtins(resolver: &mut dyn syntax::ext::base::Resolver,
                 edition,
             });
     register(sym::format_args_nl,
-             NormalTT {
+             SyntaxExtension::LegacyBang {
                  expander: Box::new(format::expand_format_args_nl),
                  def_info: None,
+                 transparency: Transparency::SemiTransparent,
                  allow_internal_unstable: Some(vec![sym::fmt_internals].into()),
                  allow_internal_unsafe: false,
                  local_inner_macros: false,
diff --git a/src/libunwind/Cargo.toml b/src/libunwind/Cargo.toml
index 4ddc878997ee5..f0f1bab425d7a 100644
--- a/src/libunwind/Cargo.toml
+++ b/src/libunwind/Cargo.toml
@@ -19,6 +19,7 @@ doc = false
 core = { path = "../libcore" }
 libc = { version = "0.2.43", features = ['rustc-dep-of-std'], default-features = false }
 compiler_builtins = "0.1.0"
+cfg-if = "0.1.8"
 
 [build-dependencies]
 cc = { optional = true, version = "1.0.1" }
diff --git a/src/libunwind/lib.rs b/src/libunwind/lib.rs
index 0ccffea317053..9182e349b196e 100644
--- a/src/libunwind/lib.rs
+++ b/src/libunwind/lib.rs
@@ -11,10 +11,7 @@
 
 #![cfg_attr(not(target_env = "msvc"), feature(libc))]
 
-#[macro_use]
-mod macros;
-
-cfg_if! {
+cfg_if::cfg_if! {
     if #[cfg(target_env = "msvc")] {
         // no extra unwinder support needed
     } else if #[cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))] {
diff --git a/src/libunwind/libunwind.rs b/src/libunwind/libunwind.rs
index 339b554ed6abd..5794e0b7683cb 100644
--- a/src/libunwind/libunwind.rs
+++ b/src/libunwind/libunwind.rs
@@ -1,10 +1,5 @@
 #![allow(nonstandard_style)]
 
-macro_rules! cfg_if {
-    ( $( if #[cfg( $meta:meta )] { $($it1:item)* } else { $($it2:item)* } )* ) =>
-        ( $( $( #[cfg($meta)] $it1)* $( #[cfg(not($meta))] $it2)* )* )
-}
-
 use libc::{c_int, c_void, uintptr_t};
 
 #[repr(C)]
@@ -82,7 +77,7 @@ extern "C" {
     pub fn _Unwind_GetDataRelBase(ctx: *mut _Unwind_Context) -> _Unwind_Ptr;
 }
 
-cfg_if! {
+cfg_if::cfg_if! {
 if #[cfg(all(any(target_os = "ios", target_os = "netbsd", not(target_arch = "arm"))))] {
     // Not ARM EHABI
     #[repr(C)]
@@ -206,7 +201,9 @@ if #[cfg(all(any(target_os = "ios", target_os = "netbsd", not(target_arch = "arm
         pc
     }
 }
+} // cfg_if!
 
+cfg_if::cfg_if! {
 if #[cfg(not(all(target_os = "ios", target_arch = "arm")))] {
     // Not 32-bit iOS
     extern "C" {
diff --git a/src/libunwind/macros.rs b/src/libunwind/macros.rs
deleted file mode 100644
index 659e977285e35..0000000000000
--- a/src/libunwind/macros.rs
+++ /dev/null
@@ -1,35 +0,0 @@
-/// A macro for defining `#[cfg]` if-else statements.
-///
-/// This is similar to the `if/elif` C preprocessor macro by allowing definition
-/// of a cascade of `#[cfg]` cases, emitting the implementation which matches
-/// first.
-///
-/// This allows you to conveniently provide a long list `#[cfg]`'d blocks of code
-/// without having to rewrite each clause multiple times.
-macro_rules! cfg_if {
-    ($(
-        if #[cfg($($meta:meta),*)] { $($it:item)* }
-    ) else * else {
-        $($it2:item)*
-    }) => {
-        __cfg_if_items! {
-            () ;
-            $( ( ($($meta),*) ($($it)*) ), )*
-            ( () ($($it2)*) ),
-        }
-    }
-}
-
-macro_rules! __cfg_if_items {
-    (($($not:meta,)*) ; ) => {};
-    (($($not:meta,)*) ; ( ($($m:meta),*) ($($it:item)*) ), $($rest:tt)*) => {
-        __cfg_if_apply! { cfg(all(not(any($($not),*)), $($m,)*)), $($it)* }
-        __cfg_if_items! { ($($not,)* $($m,)*) ; $($rest)* }
-    }
-}
-
-macro_rules! __cfg_if_apply {
-    ($m:meta, $($it:item)*) => {
-        $(#[$m] $it)*
-    }
-}
diff --git a/src/test/codegen/exact_div.rs b/src/test/codegen/intrinsics/exact_div.rs
similarity index 87%
rename from src/test/codegen/exact_div.rs
rename to src/test/codegen/intrinsics/exact_div.rs
index 6a55b492cb1e1..68eaa39997a15 100644
--- a/src/test/codegen/exact_div.rs
+++ b/src/test/codegen/intrinsics/exact_div.rs
@@ -8,13 +8,13 @@ use std::intrinsics::exact_div;
 // CHECK-LABEL: @exact_sdiv
 #[no_mangle]
 pub unsafe fn exact_sdiv(x: i32, y: i32) -> i32 {
-// CHECK: sdiv exact
+    // CHECK: sdiv exact
     exact_div(x, y)
 }
 
 // CHECK-LABEL: @exact_udiv
 #[no_mangle]
 pub unsafe fn exact_udiv(x: u32, y: u32) -> u32 {
-// CHECK: udiv exact
+    // CHECK: udiv exact
     exact_div(x, y)
 }
diff --git a/src/test/codegen/likely.rs b/src/test/codegen/intrinsics/likely.rs
similarity index 100%
rename from src/test/codegen/likely.rs
rename to src/test/codegen/intrinsics/likely.rs
diff --git a/src/test/codegen/move-val-init.rs b/src/test/codegen/intrinsics/move-val-init.rs
similarity index 100%
rename from src/test/codegen/move-val-init.rs
rename to src/test/codegen/intrinsics/move-val-init.rs
diff --git a/src/test/codegen/nontemporal.rs b/src/test/codegen/intrinsics/nontemporal.rs
similarity index 100%
rename from src/test/codegen/nontemporal.rs
rename to src/test/codegen/intrinsics/nontemporal.rs
diff --git a/src/test/codegen/prefetch.rs b/src/test/codegen/intrinsics/prefetch.rs
similarity index 100%
rename from src/test/codegen/prefetch.rs
rename to src/test/codegen/intrinsics/prefetch.rs
diff --git a/src/test/codegen/unchecked_math.rs b/src/test/codegen/intrinsics/unchecked_math.rs
similarity index 100%
rename from src/test/codegen/unchecked_math.rs
rename to src/test/codegen/intrinsics/unchecked_math.rs
diff --git a/src/test/run-pass-fulldeps/auxiliary/custom-derive-partial-eq.rs b/src/test/run-pass-fulldeps/auxiliary/custom-derive-partial-eq.rs
deleted file mode 100644
index 4d6ff47a3ee91..0000000000000
--- a/src/test/run-pass-fulldeps/auxiliary/custom-derive-partial-eq.rs
+++ /dev/null
@@ -1,71 +0,0 @@
-// force-host
-
-#![feature(plugin_registrar, rustc_private)]
-
-extern crate syntax;
-extern crate syntax_ext;
-extern crate rustc_plugin;
-
-use syntax_ext::deriving;
-use deriving::generic::*;
-use deriving::generic::ty::*;
-
-use rustc_plugin::Registry;
-use syntax::ast::*;
-use syntax::source_map::Span;
-use syntax::ext::base::*;
-use syntax::ext::build::AstBuilder;
-use syntax::symbol::Symbol;
-use syntax::ptr::P;
-
-#[plugin_registrar]
-pub fn plugin_registrar(reg: &mut Registry) {
-    reg.register_syntax_extension(Symbol::intern("derive_CustomPartialEq"),
-                                  MultiDecorator(Box::new(expand_deriving_partial_eq)));
-}
-
-fn expand_deriving_partial_eq(cx: &mut ExtCtxt, span: Span, mitem: &MetaItem, item: &Annotatable,
-                              push: &mut FnMut(Annotatable)) {
-    // structures are equal if all fields are equal, and non equal, if
-    // any fields are not equal or if the enum variants are different
-    fn cs_eq(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<Expr> {
-        cs_fold(true,
-                |cx, span, subexpr, self_f, other_fs| {
-                    let other_f = (other_fs.len(), other_fs.get(0)).1.unwrap();
-                    let eq = cx.expr_binary(span, BinOpKind::Eq, self_f, other_f.clone());
-                    cx.expr_binary(span, BinOpKind::And, subexpr, eq)
-                },
-                cx.expr_bool(span, true),
-                Box::new(|cx, span, _, _| cx.expr_bool(span, false)),
-                cx,
-                span,
-                substr)
-    }
-
-    let inline = cx.meta_word(span, Symbol::intern("inline"));
-    let attrs = vec![cx.attribute(span, inline)];
-    let methods = vec![MethodDef {
-        name: "eq",
-        generics: LifetimeBounds::empty(),
-        explicit_self: borrowed_explicit_self(),
-        args: vec![(borrowed_self(), "other")],
-        ret_ty: Literal(deriving::generic::ty::Path::new_local("bool")),
-        attributes: attrs,
-        is_unsafe: false,
-        unify_fieldless_variants: true,
-        combine_substructure: combine_substructure(Box::new(cs_eq)),
-    }];
-
-    let trait_def = TraitDef {
-        span: span,
-        attributes: Vec::new(),
-        path: deriving::generic::ty::Path::new(vec!["cmp", "PartialEq"]),
-        additional_bounds: Vec::new(),
-        generics: LifetimeBounds::empty(),
-        is_unsafe: false,
-        supports_unions: false,
-        methods: methods,
-        associated_types: Vec::new(),
-    };
-    trait_def.expand(cx, mitem, item, push)
-}
diff --git a/src/test/run-pass-fulldeps/auxiliary/custom-derive-plugin-attr.rs b/src/test/run-pass-fulldeps/auxiliary/custom-derive-plugin-attr.rs
deleted file mode 100644
index c6b33fbc75ee2..0000000000000
--- a/src/test/run-pass-fulldeps/auxiliary/custom-derive-plugin-attr.rs
+++ /dev/null
@@ -1,84 +0,0 @@
-// force-host
-
-#![feature(plugin_registrar)]
-#![feature(box_syntax)]
-#![feature(rustc_private)]
-
-extern crate syntax;
-extern crate syntax_ext;
-extern crate syntax_pos;
-extern crate rustc;
-extern crate rustc_plugin;
-
-use syntax::ast;
-use syntax::attr;
-use syntax::ext::base::{MultiDecorator, ExtCtxt, Annotatable};
-use syntax::ext::build::AstBuilder;
-use syntax::symbol::{Symbol, sym};
-use syntax::ptr::P;
-use syntax_ext::deriving::generic::{TraitDef, MethodDef, combine_substructure};
-use syntax_ext::deriving::generic::{Substructure, Struct, EnumMatching};
-use syntax_ext::deriving::generic::ty::{Literal, LifetimeBounds, Path, borrowed_explicit_self};
-use syntax_pos::Span;
-use rustc_plugin::Registry;
-
-#[plugin_registrar]
-pub fn plugin_registrar(reg: &mut Registry) {
-    reg.register_syntax_extension(
-        Symbol::intern("rustc_derive_TotalSum"),
-        MultiDecorator(box expand));
-}
-
-fn expand(cx: &mut ExtCtxt,
-          span: Span,
-          mitem: &ast::MetaItem,
-          item: &Annotatable,
-          push: &mut FnMut(Annotatable)) {
-    let trait_def = TraitDef {
-        span: span,
-        attributes: vec![],
-        path: Path::new_local("TotalSum"),
-        additional_bounds: vec![],
-        generics: LifetimeBounds::empty(),
-        associated_types: vec![],
-        is_unsafe: false,
-        supports_unions: false,
-        methods: vec![
-            MethodDef {
-                name: "total_sum",
-                generics: LifetimeBounds::empty(),
-                explicit_self: borrowed_explicit_self(),
-                args: vec![],
-                ret_ty: Literal(Path::new_local("isize")),
-                attributes: vec![],
-                is_unsafe: false,
-                unify_fieldless_variants: true,
-                combine_substructure: combine_substructure(Box::new(totalsum_substructure)),
-            },
-        ],
-    };
-
-    trait_def.expand(cx, mitem, item, push)
-}
-
-// Mostly copied from syntax::ext::deriving::hash
-/// Defines how the implementation for `trace()` is to be generated
-fn totalsum_substructure(cx: &mut ExtCtxt, trait_span: Span,
-                         substr: &Substructure) -> P<ast::Expr> {
-    let fields = match *substr.fields {
-        Struct(_, ref fs) | EnumMatching(.., ref fs) => fs,
-        _ => cx.span_bug(trait_span, "impossible substructure")
-    };
-
-    fields.iter().fold(cx.expr_isize(trait_span, 0), |acc, ref item| {
-        if attr::contains_name(&item.attrs, sym::ignore) {
-            acc
-        } else {
-            cx.expr_binary(item.span, ast::BinOpKind::Add, acc,
-                           cx.expr_method_call(item.span,
-                                               item.self_.clone(),
-                                               substr.method_ident,
-                                               Vec::new()))
-        }
-    })
-}
diff --git a/src/test/run-pass-fulldeps/auxiliary/custom-derive-plugin.rs b/src/test/run-pass-fulldeps/auxiliary/custom-derive-plugin.rs
deleted file mode 100644
index 874a0ec7c13fb..0000000000000
--- a/src/test/run-pass-fulldeps/auxiliary/custom-derive-plugin.rs
+++ /dev/null
@@ -1,76 +0,0 @@
-// force-host
-
-#![feature(plugin_registrar)]
-#![feature(box_syntax)]
-#![feature(rustc_private)]
-
-extern crate syntax;
-extern crate syntax_ext;
-extern crate syntax_pos;
-extern crate rustc;
-extern crate rustc_plugin;
-
-use syntax::ast;
-use syntax::ext::base::{MultiDecorator, ExtCtxt, Annotatable};
-use syntax::ext::build::AstBuilder;
-use syntax::symbol::Symbol;
-use syntax_ext::deriving::generic::{cs_fold, TraitDef, MethodDef, combine_substructure};
-use syntax_ext::deriving::generic::ty::{Literal, LifetimeBounds, Path, borrowed_explicit_self};
-use syntax_pos::Span;
-use rustc_plugin::Registry;
-
-#[plugin_registrar]
-pub fn plugin_registrar(reg: &mut Registry) {
-    reg.register_syntax_extension(
-        Symbol::intern("derive_TotalSum"),
-        MultiDecorator(box expand));
-
-    reg.register_syntax_extension(
-        Symbol::intern("derive_Nothing"),
-        MultiDecorator(box noop));
-}
-
-fn noop(_: &mut ExtCtxt, _: Span, _: &ast::MetaItem, _: &Annotatable, _: &mut FnMut(Annotatable)) {}
-
-fn expand(cx: &mut ExtCtxt,
-          span: Span,
-          mitem: &ast::MetaItem,
-          item: &Annotatable,
-          push: &mut FnMut(Annotatable)) {
-    let trait_def = TraitDef {
-        span: span,
-        attributes: vec![],
-        path: Path::new_local("TotalSum"),
-        additional_bounds: vec![],
-        generics: LifetimeBounds::empty(),
-        associated_types: vec![],
-        is_unsafe: false,
-        supports_unions: false,
-        methods: vec![
-            MethodDef {
-                name: "total_sum",
-                generics: LifetimeBounds::empty(),
-                explicit_self: borrowed_explicit_self(),
-                args: vec![],
-                ret_ty: Literal(Path::new_local("isize")),
-                attributes: vec![],
-                is_unsafe: false,
-                unify_fieldless_variants: true,
-                combine_substructure: combine_substructure(box |cx, span, substr| {
-                    let zero = cx.expr_isize(span, 0);
-                    cs_fold(false,
-                            |cx, span, subexpr, field, _| {
-                                cx.expr_binary(span, ast::BinOpKind::Add, subexpr,
-                                    cx.expr_method_call(span, field,
-                                        ast::Ident::from_str("total_sum"), vec![]))
-                            },
-                            zero,
-                            box |cx, span, _, _| { cx.span_bug(span, "wtf??"); },
-                            cx, span, substr)
-                }),
-            },
-        ],
-    };
-
-    trait_def.expand(cx, mitem, item, push)
-}
diff --git a/src/test/run-pass-fulldeps/auxiliary/plugin-args.rs b/src/test/run-pass-fulldeps/auxiliary/plugin-args.rs
index 096701bd9b3ed..330459fc08f55 100644
--- a/src/test/run-pass-fulldeps/auxiliary/plugin-args.rs
+++ b/src/test/run-pass-fulldeps/auxiliary/plugin-args.rs
@@ -10,11 +10,10 @@ extern crate rustc_plugin;
 
 use std::borrow::ToOwned;
 use syntax::ast;
-use syntax::ext::hygiene;
 use syntax::ext::build::AstBuilder;
-use syntax::ext::base::{TTMacroExpander, ExtCtxt, MacResult, MacEager, NormalTT};
+use syntax::ext::base::{SyntaxExtension, TTMacroExpander, ExtCtxt, MacResult, MacEager};
+use syntax::ext::hygiene::Transparency;
 use syntax::print::pprust;
-use syntax::ptr::P;
 use syntax::symbol::Symbol;
 use syntax_pos::Span;
 use syntax::tokenstream::TokenStream;
@@ -29,7 +28,7 @@ impl TTMacroExpander for Expander {
                    ecx: &'cx mut ExtCtxt,
                    sp: Span,
                    _: TokenStream,
-                   _: Option<Span>) -> Box<MacResult+'cx> {
+                   _: Option<Span>) -> Box<dyn MacResult+'cx> {
         let args = self.args.iter().map(|i| pprust::meta_list_item_to_string(i))
             .collect::<Vec<_>>().join(", ");
         MacEager::expr(ecx.expr_str(sp, Symbol::intern(&args)))
@@ -40,9 +39,10 @@ impl TTMacroExpander for Expander {
 pub fn plugin_registrar(reg: &mut Registry) {
     let args = reg.args().to_owned();
     reg.register_syntax_extension(Symbol::intern("plugin_args"),
-        NormalTT {
+        SyntaxExtension::LegacyBang {
             expander: Box::new(Expander { args: args, }),
             def_info: None,
+            transparency: Transparency::SemiTransparent,
             allow_internal_unstable: None,
             allow_internal_unsafe: false,
             local_inner_macros: false,
diff --git a/src/test/run-pass-fulldeps/custom-derive-partial-eq.rs b/src/test/run-pass-fulldeps/custom-derive-partial-eq.rs
deleted file mode 100644
index ac8fff4f6bfad..0000000000000
--- a/src/test/run-pass-fulldeps/custom-derive-partial-eq.rs
+++ /dev/null
@@ -1,10 +0,0 @@
-// aux-build:custom-derive-partial-eq.rs
-// ignore-stage1
-#![feature(plugin)]
-#![plugin(custom_derive_partial_eq)]
-#![allow(unused)]
-
-#[derive_CustomPartialEq] // Check that this is not a stability error.
-enum E { V1, V2 }
-
-fn main() {}
diff --git a/src/test/run-pass-fulldeps/derive-totalsum-attr.rs b/src/test/run-pass-fulldeps/derive-totalsum-attr.rs
deleted file mode 100644
index 38eaa71dd6aba..0000000000000
--- a/src/test/run-pass-fulldeps/derive-totalsum-attr.rs
+++ /dev/null
@@ -1,64 +0,0 @@
-// aux-build:custom-derive-plugin-attr.rs
-// ignore-stage1
-
-#![feature(plugin, rustc_attrs)]
-#![plugin(custom_derive_plugin_attr)]
-
-trait TotalSum {
-    fn total_sum(&self) -> isize;
-}
-
-impl TotalSum for isize {
-    fn total_sum(&self) -> isize {
-        *self
-    }
-}
-
-struct Seven;
-
-impl TotalSum for Seven {
-    fn total_sum(&self) -> isize {
-        7
-    }
-}
-
-#[rustc_derive_TotalSum]
-struct Foo {
-    seven: Seven,
-    bar: Bar,
-    baz: isize,
-    #[ignore]
-    nan: NaN,
-}
-
-#[rustc_derive_TotalSum]
-struct Bar {
-    quux: isize,
-    bleh: isize,
-    #[ignore]
-    nan: NaN2
-}
-
-struct NaN;
-
-impl TotalSum for NaN {
-    fn total_sum(&self) -> isize {
-        panic!();
-    }
-}
-
-struct NaN2;
-
-pub fn main() {
-    let v = Foo {
-        seven: Seven,
-        bar: Bar {
-            quux: 9,
-            bleh: 3,
-            nan: NaN2
-        },
-        baz: 80,
-        nan: NaN
-    };
-    assert_eq!(v.total_sum(), 99);
-}
diff --git a/src/test/run-pass-fulldeps/derive-totalsum.rs b/src/test/run-pass-fulldeps/derive-totalsum.rs
deleted file mode 100644
index 2b0bb51d90aec..0000000000000
--- a/src/test/run-pass-fulldeps/derive-totalsum.rs
+++ /dev/null
@@ -1,49 +0,0 @@
-// aux-build:custom-derive-plugin.rs
-// ignore-stage1
-
-#![feature(plugin)]
-#![plugin(custom_derive_plugin)]
-
-trait TotalSum {
-    fn total_sum(&self) -> isize;
-}
-
-impl TotalSum for isize {
-    fn total_sum(&self) -> isize {
-        *self
-    }
-}
-
-struct Seven;
-
-impl TotalSum for Seven {
-    fn total_sum(&self) -> isize {
-        7
-    }
-}
-
-#[derive_TotalSum]
-struct Foo {
-    seven: Seven,
-    bar: Bar,
-    baz: isize,
-}
-
-#[derive_TotalSum]
-struct Bar {
-    quux: isize,
-    bleh: isize,
-}
-
-
-pub fn main() {
-    let v = Foo {
-        seven: Seven,
-        bar: Bar {
-            quux: 9,
-            bleh: 3,
-        },
-        baz: 80,
-    };
-    assert_eq!(v.total_sum(), 99);
-}
diff --git a/src/test/run-pass-fulldeps/issue-40663.rs b/src/test/run-pass-fulldeps/issue-40663.rs
deleted file mode 100644
index 133f6302bde57..0000000000000
--- a/src/test/run-pass-fulldeps/issue-40663.rs
+++ /dev/null
@@ -1,13 +0,0 @@
-#![allow(dead_code)]
-// aux-build:custom-derive-plugin.rs
-// ignore-stage1
-
-#![feature(plugin)]
-#![plugin(custom_derive_plugin)]
-
-#[derive_Nothing]
-#[derive_Nothing]
-#[derive_Nothing]
-struct S;
-
-fn main() {}
diff --git a/src/test/ui/const-generics/issue-61336-1.rs b/src/test/ui/const-generics/issue-61336-1.rs
new file mode 100644
index 0000000000000..5b5e431bf2ff6
--- /dev/null
+++ b/src/test/ui/const-generics/issue-61336-1.rs
@@ -0,0 +1,12 @@
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+fn f<T: Copy, const N: usize>(x: T) -> [T; N] {
+    [x; N]
+    //~^ ERROR array lengths can't depend on generic parameters
+}
+
+fn main() {
+    let x: [u32; 5] = f::<u32, 5>(3);
+    assert_eq!(x, [3u32; 5]);
+}
diff --git a/src/test/ui/const-generics/issue-61336-1.stderr b/src/test/ui/const-generics/issue-61336-1.stderr
new file mode 100644
index 0000000000000..1a5bb9f763bcf
--- /dev/null
+++ b/src/test/ui/const-generics/issue-61336-1.stderr
@@ -0,0 +1,14 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+  --> $DIR/issue-61336-1.rs:1:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+
+error: array lengths can't depend on generic parameters
+  --> $DIR/issue-61336-1.rs:5:9
+   |
+LL |     [x; N]
+   |         ^
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/const-generics/issue-61336.rs b/src/test/ui/const-generics/issue-61336.rs
new file mode 100644
index 0000000000000..95930371d5974
--- /dev/null
+++ b/src/test/ui/const-generics/issue-61336.rs
@@ -0,0 +1,16 @@
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+fn f<T: Copy, const N: usize>(x: T) -> [T; N] {
+    [x; N]
+}
+
+fn g<T, const N: usize>(x: T) -> [T; N] {
+    [x; N]
+    //~^ ERROR the trait bound `T: std::marker::Copy` is not satisfied [E0277]
+}
+
+fn main() {
+    let x: [u32; 5] = f::<u32, 5>(3);
+    assert_eq!(x, [3u32; 5]);
+}
diff --git a/src/test/ui/const-generics/issue-61336.stderr b/src/test/ui/const-generics/issue-61336.stderr
new file mode 100644
index 0000000000000..9939a5998340f
--- /dev/null
+++ b/src/test/ui/const-generics/issue-61336.stderr
@@ -0,0 +1,18 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+  --> $DIR/issue-61336.rs:1:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+
+error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied
+  --> $DIR/issue-61336.rs:9:5
+   |
+LL |     [x; N]
+   |     ^^^^^^ the trait `std::marker::Copy` is not implemented for `T`
+   |
+   = help: consider adding a `where T: std::marker::Copy` bound
+   = note: the `Copy` trait is required because the repeated element will be copied
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/macros/nonterminal-matching.stderr b/src/test/ui/macros/nonterminal-matching.stderr
index 5fba8002e1c48..93cc97d45830b 100644
--- a/src/test/ui/macros/nonterminal-matching.stderr
+++ b/src/test/ui/macros/nonterminal-matching.stderr
@@ -1,6 +1,9 @@
 error: no rules expected the token `enum E { }`
   --> $DIR/nonterminal-matching.rs:19:10
    |
+LL |     macro n(a $nt_item b) {
+   |     --------------------- when calling this macro
+...
 LL |     n!(a $nt_item b);
    |          ^^^^^^^^ no rules expected this token in macro call
 ...