diff --git a/Cargo.lock b/Cargo.lock
index fa749e5e3aebe..5b446c517c915 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3325,8 +3325,6 @@ dependencies = [
  "log",
  "rustc",
  "rustc_data_structures",
- "rustc_errors",
- "syntax",
  "syntax_pos",
 ]
 
@@ -3348,7 +3346,6 @@ dependencies = [
  "log",
  "memmap",
  "num_cpus",
- "parking_lot 0.9.0",
  "rustc",
  "rustc_apfloat",
  "rustc_codegen_utils",
@@ -3367,7 +3364,6 @@ dependencies = [
 name = "rustc_codegen_utils"
 version = "0.0.0"
 dependencies = [
- "flate2",
  "log",
  "punycode",
  "rustc",
@@ -3562,7 +3558,6 @@ name = "rustc_mir"
 version = "0.0.0"
 dependencies = [
  "arena",
- "byteorder",
  "either",
  "graphviz",
  "log",
@@ -3615,7 +3610,6 @@ name = "rustc_plugin_impl"
 version = "0.0.0"
 dependencies = [
  "rustc",
- "rustc_errors",
  "rustc_metadata",
  "syntax",
  "syntax_pos",
@@ -3639,7 +3633,6 @@ version = "0.0.0"
 dependencies = [
  "arena",
  "bitflags",
- "indexmap",
  "log",
  "rustc",
  "rustc_data_structures",
@@ -3661,7 +3654,6 @@ dependencies = [
  "rustc_codegen_utils",
  "rustc_data_structures",
  "rustc_target",
- "rustc_typeck",
  "serde_json",
  "syntax",
  "syntax_pos",
@@ -3692,9 +3684,7 @@ checksum = "b725dadae9fabc488df69a287f5a99c5eaf5d10853842a8a3dfac52476f544ee"
 name = "rustc_traits"
 version = "0.0.0"
 dependencies = [
- "bitflags",
  "chalk-engine",
- "graphviz",
  "log",
  "rustc",
  "rustc_data_structures",
@@ -4057,7 +4047,6 @@ version = "0.0.0"
 dependencies = [
  "alloc",
  "backtrace",
- "cc",
  "cfg-if",
  "compiler_builtins",
  "core",
@@ -4242,7 +4231,6 @@ dependencies = [
  "rustc_data_structures",
  "rustc_errors",
  "rustc_lexer",
- "rustc_macros",
  "rustc_target",
  "scoped-tls",
  "serialize",
@@ -4258,7 +4246,6 @@ dependencies = [
  "log",
  "rustc_data_structures",
  "rustc_errors",
- "rustc_lexer",
  "rustc_target",
  "smallvec",
  "syntax",
diff --git a/src/libcore/iter/traits/iterator.rs b/src/libcore/iter/traits/iterator.rs
index da49223dfb285..0a9e076ec5869 100644
--- a/src/libcore/iter/traits/iterator.rs
+++ b/src/libcore/iter/traits/iterator.rs
@@ -2581,7 +2581,7 @@ pub trait Iterator {
     /// assert_eq!(xs.iter().cmp_by(&ys, |&x, &y| (x * x).cmp(&y)), Ordering::Equal);
     /// assert_eq!(xs.iter().cmp_by(&ys, |&x, &y| (2 * x).cmp(&y)), Ordering::Greater);
     /// ```
-    #[unstable(feature = "iter_order_by", issue = "0")]
+    #[unstable(feature = "iter_order_by", issue = "64295")]
     fn cmp_by<I, F>(mut self, other: I, mut cmp: F) -> Ordering
     where
         Self: Sized,
@@ -2664,7 +2664,7 @@ pub trait Iterator {
     ///     Some(Ordering::Greater)
     /// );
     /// ```
-    #[unstable(feature = "iter_order_by", issue = "0")]
+    #[unstable(feature = "iter_order_by", issue = "64295")]
     fn partial_cmp_by<I, F>(mut self, other: I, mut partial_cmp: F) -> Option<Ordering>
     where
         Self: Sized,
@@ -2729,7 +2729,7 @@ pub trait Iterator {
     ///
     /// assert!(xs.iter().eq_by(&ys, |&x, &y| x * x == y));
     /// ```
-    #[unstable(feature = "iter_order_by", issue = "0")]
+    #[unstable(feature = "iter_order_by", issue = "64295")]
     fn eq_by<I, F>(mut self, other: I, mut eq: F) -> bool
     where
         Self: Sized,
diff --git a/src/librustc_ast_borrowck/Cargo.toml b/src/librustc_ast_borrowck/Cargo.toml
index 024b2640e1e8e..40c4c1fc3fee6 100644
--- a/src/librustc_ast_borrowck/Cargo.toml
+++ b/src/librustc_ast_borrowck/Cargo.toml
@@ -12,11 +12,9 @@ doctest = false
 
 [dependencies]
 log = "0.4"
-syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
 # for "clarity", rename the graphviz crate to dot; graphviz within `borrowck`
 # refers to the borrowck-specific graphviz adapter traits.
 dot = { path = "../libgraphviz", package = "graphviz" }
 rustc = { path = "../librustc" }
-errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }
diff --git a/src/librustc_codegen_ssa/Cargo.toml b/src/librustc_codegen_ssa/Cargo.toml
index bc028d6624279..2e3666e609657 100644
--- a/src/librustc_codegen_ssa/Cargo.toml
+++ b/src/librustc_codegen_ssa/Cargo.toml
@@ -17,7 +17,6 @@ memmap = "0.6"
 log = "0.4.5"
 libc = "0.2.44"
 jobserver = "0.1.11"
-parking_lot = "0.9"
 tempfile = "3.1"
 
 rustc_serialize = { path = "../libserialize", package = "serialize" }
diff --git a/src/librustc_codegen_utils/Cargo.toml b/src/librustc_codegen_utils/Cargo.toml
index 89b50c5daccae..c8c219d039a73 100644
--- a/src/librustc_codegen_utils/Cargo.toml
+++ b/src/librustc_codegen_utils/Cargo.toml
@@ -10,7 +10,6 @@ path = "lib.rs"
 test = false
 
 [dependencies]
-flate2 = "1.0"
 log = "0.4"
 punycode = "0.4.0"
 rustc-demangle = "0.1.16"
diff --git a/src/librustc_mir/Cargo.toml b/src/librustc_mir/Cargo.toml
index 0691390bead4b..f296753a0304c 100644
--- a/src/librustc_mir/Cargo.toml
+++ b/src/librustc_mir/Cargo.toml
@@ -24,6 +24,5 @@ rustc_lexer = { path = "../librustc_lexer" }
 rustc_serialize = { path = "../libserialize", package = "serialize" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
-byteorder = { version = "1.3" }
 rustc_apfloat = { path = "../librustc_apfloat" }
 smallvec = { version = "0.6.7", features = ["union", "may_dangle"] }
diff --git a/src/librustc_mir/error_codes.rs b/src/librustc_mir/error_codes.rs
index ba299e9463b8d..196bcf147f8f8 100644
--- a/src/librustc_mir/error_codes.rs
+++ b/src/librustc_mir/error_codes.rs
@@ -1993,6 +1993,69 @@ fn get_owned_iterator() -> IntoIter<i32> {
 ```
 "##,
 
+E0524: r##"
+A variable which requires unique access is being used in more than one closure
+at the same time.
+
+Erroneous code example:
+
+```compile_fail,E0524
+fn set(x: &mut isize) {
+    *x += 4;
+}
+
+fn dragoooon(x: &mut isize) {
+    let mut c1 = || set(x);
+    let mut c2 = || set(x); // error!
+
+    c2();
+    c1();
+}
+```
+
+To solve this issue, multiple solutions are available. First, is it required
+for this variable to be used in more than one closure at a time? If it is the
+case, use reference counted types such as `Rc` (or `Arc` if it runs
+concurrently):
+
+```
+use std::rc::Rc;
+use std::cell::RefCell;
+
+fn set(x: &mut isize) {
+    *x += 4;
+}
+
+fn dragoooon(x: &mut isize) {
+    let x = Rc::new(RefCell::new(x));
+    let y = Rc::clone(&x);
+    let mut c1 = || { let mut x2 = x.borrow_mut(); set(&mut x2); };
+    let mut c2 = || { let mut x2 = y.borrow_mut(); set(&mut x2); }; // ok!
+
+    c2();
+    c1();
+}
+```
+
+If not, just run closures one at a time:
+
+```
+fn set(x: &mut isize) {
+    *x += 4;
+}
+
+fn dragoooon(x: &mut isize) {
+    { // This block isn't necessary since non-lexical lifetimes, it's just to
+      // make it more clear.
+        let mut c1 = || set(&mut *x);
+        c1();
+    } // `c1` has been dropped here so we're free to use `x` again!
+    let mut c2 = || set(&mut *x);
+    c2();
+}
+```
+"##,
+
 E0595: r##"
 #### Note: this error code is no longer emitted by the compiler.
 
@@ -2393,7 +2456,6 @@ There are some known bugs that trigger this message.
 //  E0385, // {} in an aliasable location
     E0493, // destructors cannot be evaluated at compile-time
     E0521, // borrowed data escapes outside of closure
-    E0524, // two closures require unique access to `..` at the same time
     E0526, // shuffle indices are not constant
     E0594, // cannot assign to {}
 //  E0598, // lifetime of {} is too short to guarantee its contents can be...
diff --git a/src/librustc_plugin/Cargo.toml b/src/librustc_plugin/Cargo.toml
index 84a743ed1ad7d..3f11430dc82cb 100644
--- a/src/librustc_plugin/Cargo.toml
+++ b/src/librustc_plugin/Cargo.toml
@@ -15,4 +15,3 @@ rustc = { path = "../librustc" }
 rustc_metadata = { path = "../librustc_metadata" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
-rustc_errors = { path = "../librustc_errors" }
diff --git a/src/librustc_resolve/Cargo.toml b/src/librustc_resolve/Cargo.toml
index 548f982fe3bf0..936e72ef2c571 100644
--- a/src/librustc_resolve/Cargo.toml
+++ b/src/librustc_resolve/Cargo.toml
@@ -12,7 +12,6 @@ doctest = false
 
 [dependencies]
 bitflags = "1.0"
-indexmap = "1"
 log = "0.4"
 syntax = { path = "../libsyntax" }
 rustc = { path = "../librustc" }
diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs
index 3900a3dbb3872..73ad0670659b5 100644
--- a/src/librustc_resolve/macros.rs
+++ b/src/librustc_resolve/macros.rs
@@ -18,7 +18,7 @@ use syntax::ext::base::{self, InvocationRes, Indeterminate, SpecialDerives};
 use syntax::ext::base::{MacroKind, SyntaxExtension};
 use syntax::ext::expand::{AstFragment, AstFragmentKind, Invocation, InvocationKind};
 use syntax::ext::hygiene::{self, ExpnId, ExpnData, ExpnKind};
-use syntax::ext::tt::macro_rules;
+use syntax::ext::compile_declarative_macro;
 use syntax::feature_gate::{emit_feature_err, is_builtin_attr_name};
 use syntax::feature_gate::GateIssue;
 use syntax::symbol::{Symbol, kw, sym};
@@ -843,7 +843,7 @@ impl<'a> Resolver<'a> {
     /// Compile the macro into a `SyntaxExtension` and possibly replace it with a pre-defined
     /// extension partially or entirely for built-in macros and legacy plugin macros.
     crate fn compile_macro(&mut self, item: &ast::Item, edition: Edition) -> SyntaxExtension {
-        let mut result = macro_rules::compile(
+        let mut result = compile_declarative_macro(
             &self.session.parse_sess, self.session.features_untracked(), item, edition
         );
 
diff --git a/src/librustc_save_analysis/Cargo.toml b/src/librustc_save_analysis/Cargo.toml
index 88bb76d2aba3a..b89c83d630b7d 100644
--- a/src/librustc_save_analysis/Cargo.toml
+++ b/src/librustc_save_analysis/Cargo.toml
@@ -14,7 +14,6 @@ rustc = { path = "../librustc" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_codegen_utils = { path = "../librustc_codegen_utils" }
 rustc_target = { path = "../librustc_target" }
-rustc_typeck = { path = "../librustc_typeck" }
 serde_json = "1"
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
diff --git a/src/librustc_traits/Cargo.toml b/src/librustc_traits/Cargo.toml
index bb28ac839a544..b86a3a5e9639b 100644
--- a/src/librustc_traits/Cargo.toml
+++ b/src/librustc_traits/Cargo.toml
@@ -9,8 +9,6 @@ name = "rustc_traits"
 path = "lib.rs"
 
 [dependencies]
-bitflags = "1.0"
-graphviz = { path = "../libgraphviz" }
 log = { version = "0.4" }
 rustc = { path = "../librustc" }
 rustc_data_structures = { path = "../librustc_data_structures" }
diff --git a/src/libstd/Cargo.toml b/src/libstd/Cargo.toml
index af1d2402f88e7..ee4b367b5c5b9 100644
--- a/src/libstd/Cargo.toml
+++ b/src/libstd/Cargo.toml
@@ -53,9 +53,6 @@ fortanix-sgx-abi = { version = "0.3.2", features = ['rustc-dep-of-std'] }
 [target.wasm32-wasi.dependencies]
 wasi = { version = "0.7.0", features = ['rustc-dep-of-std', 'alloc'] }
 
-[build-dependencies]
-cc = "1.0"
-
 [features]
 default = ["std_detect_file_io", "std_detect_dlsym_getauxval"]
 
diff --git a/src/libstd/fs.rs b/src/libstd/fs.rs
index b5265fe369e83..8933f027a065f 100644
--- a/src/libstd/fs.rs
+++ b/src/libstd/fs.rs
@@ -114,6 +114,9 @@ pub struct Metadata(fs_imp::FileAttr);
 /// information like the entry's path and possibly other metadata can be
 /// learned.
 ///
+/// The order in which this iterator returns entries is platform and filesystem
+/// dependent.
+///
 /// # Errors
 ///
 /// This [`io::Result`] will be an [`Err`] if there's some sort of intermittent
@@ -1962,6 +1965,9 @@ pub fn remove_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
 ///
 /// [changes]: ../io/index.html#platform-specific-behavior
 ///
+/// The order in which this iterator returns entries is platform and filesystem
+/// dependent.
+///
 /// # Errors
 ///
 /// This function will return an error in the following situations, but is not
@@ -1994,6 +2000,25 @@ pub fn remove_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
 ///     Ok(())
 /// }
 /// ```
+///
+/// ```rust,no_run
+/// use std::{fs, io};
+///
+/// fn main() -> io::Result<()> {
+///     let mut entries = fs::read_dir(".")?
+///         .map(|res| res.map(|e| e.path()))
+///         .collect::<Result<Vec<_>, io::Error>>()?;
+///
+///     // The order in which `read_dir` returns entries is not guaranteed. If reproducible
+///     // ordering is required the entries should be explicitly sorted.
+///
+///     entries.sort();
+///
+///     // The entries have now been sorted by their path.
+///
+///     Ok(())
+/// }
+/// ```
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn read_dir<P: AsRef<Path>>(path: P) -> io::Result<ReadDir> {
     fs_imp::readdir(path.as_ref()).map(ReadDir)
diff --git a/src/libstd/thread/local.rs b/src/libstd/thread/local.rs
index f85b5d632f16b..e92c0d1c58e41 100644
--- a/src/libstd/thread/local.rs
+++ b/src/libstd/thread/local.rs
@@ -236,8 +236,8 @@ impl<T: 'static> LocalKey<T> {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn with<F, R>(&'static self, f: F) -> R
                       where F: FnOnce(&T) -> R {
-        self.try_with(f).expect("cannot access a TLS value during or \
-                                 after it is destroyed")
+        self.try_with(f).expect("cannot access a Thread Local Storage value \
+                                 during or after destruction")
     }
 
     /// Acquires a reference to the value in this TLS key.
diff --git a/src/libsyntax/Cargo.toml b/src/libsyntax/Cargo.toml
index d4a9acc1569b4..196cf4d9dfae8 100644
--- a/src/libsyntax/Cargo.toml
+++ b/src/libsyntax/Cargo.toml
@@ -19,6 +19,5 @@ syntax_pos = { path = "../libsyntax_pos" }
 errors = { path = "../librustc_errors", package = "rustc_errors" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_lexer = { path = "../librustc_lexer" }
-rustc_macros = { path = "../librustc_macros" }
 rustc_target = { path = "../librustc_target" }
 smallvec = { version = "0.6.7", features = ["union", "may_dangle"] }
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index b80c530731dfc..2cd802f22d306 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -6,7 +6,7 @@ use crate::config::StripUnconfigured;
 use crate::ext::base::*;
 use crate::ext::proc_macro::{collect_derives, MarkAttrs};
 use crate::ext::hygiene::{ExpnId, SyntaxContext, ExpnData, ExpnKind};
-use crate::ext::tt::macro_rules::annotate_err_with_kind;
+use crate::ext::mbe::macro_rules::annotate_err_with_kind;
 use crate::ext::placeholders::{placeholder, PlaceholderExpander};
 use crate::feature_gate::{self, Features, GateIssue, is_builtin_attr, emit_feature_err};
 use crate::mut_visit::*;
@@ -115,8 +115,8 @@ macro_rules! ast_fragments {
             }
         }
 
-        impl<'a> MacResult for crate::ext::tt::macro_rules::ParserAnyMacro<'a> {
-            $(fn $make_ast(self: Box<crate::ext::tt::macro_rules::ParserAnyMacro<'a>>)
+        impl<'a> MacResult for crate::ext::mbe::macro_rules::ParserAnyMacro<'a> {
+            $(fn $make_ast(self: Box<crate::ext::mbe::macro_rules::ParserAnyMacro<'a>>)
                            -> Option<$AstTy> {
                 Some(self.make(AstFragmentKind::$Kind).$make_ast())
             })*
diff --git a/src/libsyntax/ext/mbe.rs b/src/libsyntax/ext/mbe.rs
new file mode 100644
index 0000000000000..a87da791c9b4f
--- /dev/null
+++ b/src/libsyntax/ext/mbe.rs
@@ -0,0 +1,166 @@
+//! This module implements declarative macros: old `macro_rules` and the newer
+//! `macro`. Declarative macros are also known as "macro by example", and that's
+//! why we call this module `mbe`. For external documentation, prefer the
+//! official terminology: "declarative macros".
+
+crate mod transcribe;
+crate mod macro_check;
+crate mod macro_parser;
+crate mod macro_rules;
+crate mod quoted;
+
+use crate::ast;
+use crate::parse::token::{self, Token, TokenKind};
+use crate::tokenstream::{DelimSpan};
+
+use syntax_pos::{BytePos, Span};
+
+use rustc_data_structures::sync::Lrc;
+
+/// Contains the sub-token-trees of a "delimited" token tree, such as the contents of `(`. Note
+/// that the delimiter itself might be `NoDelim`.
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
+struct Delimited {
+    delim: token::DelimToken,
+    tts: Vec<TokenTree>,
+}
+
+impl Delimited {
+    /// Returns a `self::TokenTree` with a `Span` corresponding to the opening delimiter.
+    fn open_tt(&self, span: Span) -> TokenTree {
+        let open_span = if span.is_dummy() {
+            span
+        } else {
+            span.with_hi(span.lo() + BytePos(self.delim.len() as u32))
+        };
+        TokenTree::token(token::OpenDelim(self.delim), open_span)
+    }
+
+    /// Returns a `self::TokenTree` with a `Span` corresponding to the closing delimiter.
+    fn close_tt(&self, span: Span) -> TokenTree {
+        let close_span = if span.is_dummy() {
+            span
+        } else {
+            span.with_lo(span.hi() - BytePos(self.delim.len() as u32))
+        };
+        TokenTree::token(token::CloseDelim(self.delim), close_span)
+    }
+}
+
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
+struct SequenceRepetition {
+    /// The sequence of token trees
+    tts: Vec<TokenTree>,
+    /// The optional separator
+    separator: Option<Token>,
+    /// Whether the sequence can be repeated zero (*), or one or more times (+)
+    kleene: KleeneToken,
+    /// The number of `Match`s that appear in the sequence (and subsequences)
+    num_captures: usize,
+}
+
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
+struct KleeneToken {
+    span: Span,
+    op: KleeneOp,
+}
+
+impl KleeneToken {
+    fn new(op: KleeneOp, span: Span) -> KleeneToken {
+        KleeneToken { span, op }
+    }
+}
+
+/// A Kleene-style [repetition operator](http://en.wikipedia.org/wiki/Kleene_star)
+/// for token sequences.
+#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+enum KleeneOp {
+    /// Kleene star (`*`) for zero or more repetitions
+    ZeroOrMore,
+    /// Kleene plus (`+`) for one or more repetitions
+    OneOrMore,
+    /// Kleene optional (`?`) for zero or one reptitions
+    ZeroOrOne,
+}
+
+/// Similar to `tokenstream::TokenTree`, except that `$i`, `$i:ident`, and `$(...)`
+/// are "first-class" token trees. Useful for parsing macros.
+#[derive(Debug, Clone, PartialEq, RustcEncodable, RustcDecodable)]
+enum TokenTree {
+    Token(Token),
+    Delimited(DelimSpan, Lrc<Delimited>),
+    /// A kleene-style repetition sequence
+    Sequence(DelimSpan, Lrc<SequenceRepetition>),
+    /// e.g., `$var`
+    MetaVar(Span, ast::Ident),
+    /// e.g., `$var:expr`. This is only used in the left hand side of MBE macros.
+    MetaVarDecl(
+        Span,
+        ast::Ident, /* name to bind */
+        ast::Ident, /* kind of nonterminal */
+    ),
+}
+
+impl TokenTree {
+    /// Return the number of tokens in the tree.
+    fn len(&self) -> usize {
+        match *self {
+            TokenTree::Delimited(_, ref delimed) => match delimed.delim {
+                token::NoDelim => delimed.tts.len(),
+                _ => delimed.tts.len() + 2,
+            },
+            TokenTree::Sequence(_, ref seq) => seq.tts.len(),
+            _ => 0,
+        }
+    }
+
+    /// Returns `true` if the given token tree is delimited.
+    fn is_delimited(&self) -> bool {
+        match *self {
+            TokenTree::Delimited(..) => true,
+            _ => false,
+        }
+    }
+
+    /// Returns `true` if the given token tree is a token of the given kind.
+    fn is_token(&self, expected_kind: &TokenKind) -> bool {
+        match self {
+            TokenTree::Token(Token { kind: actual_kind, .. }) => actual_kind == expected_kind,
+            _ => false,
+        }
+    }
+
+    /// Gets the `index`-th sub-token-tree. This only makes sense for delimited trees and sequences.
+    fn get_tt(&self, index: usize) -> TokenTree {
+        match (self, index) {
+            (&TokenTree::Delimited(_, ref delimed), _) if delimed.delim == token::NoDelim => {
+                delimed.tts[index].clone()
+            }
+            (&TokenTree::Delimited(span, ref delimed), _) => {
+                if index == 0 {
+                    return delimed.open_tt(span.open);
+                }
+                if index == delimed.tts.len() + 1 {
+                    return delimed.close_tt(span.close);
+                }
+                delimed.tts[index - 1].clone()
+            }
+            (&TokenTree::Sequence(_, ref seq), _) => seq.tts[index].clone(),
+            _ => panic!("Cannot expand a token tree"),
+        }
+    }
+
+    /// Retrieves the `TokenTree`'s span.
+    fn span(&self) -> Span {
+        match *self {
+            TokenTree::Token(Token { span, .. })
+            | TokenTree::MetaVar(span, _)
+            | TokenTree::MetaVarDecl(span, _, _) => span,
+            TokenTree::Delimited(span, _) | TokenTree::Sequence(span, _) => span.entire(),
+        }
+    }
+
+    fn token(kind: TokenKind, span: Span) -> TokenTree {
+        TokenTree::Token(Token::new(kind, span))
+    }
+}
diff --git a/src/libsyntax/ext/tt/macro_check.rs b/src/libsyntax/ext/mbe/macro_check.rs
similarity index 99%
rename from src/libsyntax/ext/tt/macro_check.rs
rename to src/libsyntax/ext/mbe/macro_check.rs
index 5af97199902e6..97074f5cbe46c 100644
--- a/src/libsyntax/ext/tt/macro_check.rs
+++ b/src/libsyntax/ext/mbe/macro_check.rs
@@ -106,7 +106,7 @@
 //! bound.
 use crate::ast::NodeId;
 use crate::early_buffered_lints::BufferedEarlyLintId;
-use crate::ext::tt::quoted::{KleeneToken, TokenTree};
+use crate::ext::mbe::{KleeneToken, TokenTree};
 use crate::parse::token::TokenKind;
 use crate::parse::token::{DelimToken, Token};
 use crate::parse::ParseSess;
@@ -196,7 +196,7 @@ struct MacroState<'a> {
 /// - `node_id` is used to emit lints
 /// - `span` is used when no spans are available
 /// - `lhses` and `rhses` should have the same length and represent the macro definition
-pub fn check_meta_variables(
+pub(super) fn check_meta_variables(
     sess: &ParseSess,
     node_id: NodeId,
     span: Span,
diff --git a/src/libsyntax/ext/tt/macro_parser.rs b/src/libsyntax/ext/mbe/macro_parser.rs
similarity index 98%
rename from src/libsyntax/ext/tt/macro_parser.rs
rename to src/libsyntax/ext/mbe/macro_parser.rs
index dbf14daa30e75..b51384d3b15e1 100644
--- a/src/libsyntax/ext/tt/macro_parser.rs
+++ b/src/libsyntax/ext/mbe/macro_parser.rs
@@ -70,12 +70,12 @@
 //! eof: [a $( a )* a b ·]
 //! ```
 
-pub use NamedMatch::*;
-pub use ParseResult::*;
+crate use NamedMatch::*;
+crate use ParseResult::*;
 use TokenTreeOrTokenTreeSlice::*;
 
 use crate::ast::{Ident, Name};
-use crate::ext::tt::quoted::{self, TokenTree};
+use crate::ext::mbe::{self, TokenTree};
 use crate::parse::{Directory, ParseSess};
 use crate::parse::parser::{Parser, PathStyle};
 use crate::parse::token::{self, DocComment, Nonterminal, Token};
@@ -195,7 +195,7 @@ struct MatcherPos<'root, 'tt> {
     // `None`.
 
     /// The KleeneOp of this sequence if we are in a repetition.
-    seq_op: Option<quoted::KleeneOp>,
+    seq_op: Option<mbe::KleeneOp>,
 
     /// The separator if we are in a repetition.
     sep: Option<Token>,
@@ -267,7 +267,7 @@ impl<'root, 'tt> DerefMut for MatcherPosHandle<'root, 'tt> {
 }
 
 /// Represents the possible results of an attempted parse.
-pub enum ParseResult<T> {
+crate enum ParseResult<T> {
     /// Parsed successfully.
     Success(T),
     /// Arm failed to match. If the second parameter is `token::Eof`, it indicates an unexpected
@@ -279,10 +279,10 @@ pub enum ParseResult<T> {
 
 /// A `ParseResult` where the `Success` variant contains a mapping of `Ident`s to `NamedMatch`es.
 /// This represents the mapping of metavars to the token trees they bind to.
-pub type NamedParseResult = ParseResult<FxHashMap<Ident, NamedMatch>>;
+crate type NamedParseResult = ParseResult<FxHashMap<Ident, NamedMatch>>;
 
 /// Count how many metavars are named in the given matcher `ms`.
-pub fn count_names(ms: &[TokenTree]) -> usize {
+pub(super) fn count_names(ms: &[TokenTree]) -> usize {
     ms.iter().fold(0, |count, elt| {
         count + match *elt {
             TokenTree::Sequence(_, ref seq) => seq.num_captures,
@@ -352,7 +352,7 @@ fn initial_matcher_pos<'root, 'tt>(ms: &'tt [TokenTree], open: Span) -> MatcherP
 /// only on the nesting depth of `ast::TTSeq`s in the originating
 /// token tree it was derived from.
 #[derive(Debug, Clone)]
-pub enum NamedMatch {
+crate enum NamedMatch {
     MatchedSeq(Lrc<NamedMatchVec>, DelimSpan),
     MatchedNonterminal(Lrc<Nonterminal>),
 }
@@ -415,7 +415,7 @@ fn nameize<I: Iterator<Item = NamedMatch>>(
 
 /// Generates an appropriate parsing failure message. For EOF, this is "unexpected end...". For
 /// other tokens, this is "unexpected token...".
-pub fn parse_failure_msg(tok: &Token) -> String {
+crate fn parse_failure_msg(tok: &Token) -> String {
     match tok.kind {
         token::Eof => "unexpected end of macro invocation".to_string(),
         _ => format!(
@@ -532,7 +532,7 @@ fn inner_parse_loop<'root, 'tt>(
                 }
                 // We don't need a separator. Move the "dot" back to the beginning of the matcher
                 // and try to match again UNLESS we are only allowed to have _one_ repetition.
-                else if item.seq_op != Some(quoted::KleeneOp::ZeroOrOne) {
+                else if item.seq_op != Some(mbe::KleeneOp::ZeroOrOne) {
                     item.match_cur = item.match_lo;
                     item.idx = 0;
                     cur_items.push(item);
@@ -555,8 +555,8 @@ fn inner_parse_loop<'root, 'tt>(
                     // implicitly disallowing OneOrMore from having 0 matches here. Thus, that will
                     // result in a "no rules expected token" error by virtue of this matcher not
                     // working.
-                    if seq.kleene.op == quoted::KleeneOp::ZeroOrMore
-                        || seq.kleene.op == quoted::KleeneOp::ZeroOrOne
+                    if seq.kleene.op == mbe::KleeneOp::ZeroOrMore
+                        || seq.kleene.op == mbe::KleeneOp::ZeroOrOne
                     {
                         let mut new_item = item.clone();
                         new_item.match_cur += seq.num_captures;
@@ -648,7 +648,7 @@ fn inner_parse_loop<'root, 'tt>(
 /// - `directory`: Information about the file locations (needed for the black-box parser)
 /// - `recurse_into_modules`: Whether or not to recurse into modules (needed for the black-box
 ///   parser)
-pub fn parse(
+pub(super) fn parse(
     sess: &ParseSess,
     tts: TokenStream,
     ms: &[TokenTree],
diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/mbe/macro_rules.rs
similarity index 90%
rename from src/libsyntax/ext/tt/macro_rules.rs
rename to src/libsyntax/ext/mbe/macro_rules.rs
index b27e9c543377a..816baadb12fbb 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/mbe/macro_rules.rs
@@ -4,12 +4,12 @@ use crate::edition::Edition;
 use crate::ext::base::{DummyResult, ExtCtxt, MacResult, TTMacroExpander};
 use crate::ext::base::{SyntaxExtension, SyntaxExtensionKind};
 use crate::ext::expand::{AstFragment, AstFragmentKind};
-use crate::ext::tt::macro_check;
-use crate::ext::tt::macro_parser::{parse, parse_failure_msg};
-use crate::ext::tt::macro_parser::{Error, Failure, Success};
-use crate::ext::tt::macro_parser::{MatchedNonterminal, MatchedSeq};
-use crate::ext::tt::quoted;
-use crate::ext::tt::transcribe::transcribe;
+use crate::ext::mbe;
+use crate::ext::mbe::macro_check;
+use crate::ext::mbe::macro_parser::{parse, parse_failure_msg};
+use crate::ext::mbe::macro_parser::{Error, Failure, Success};
+use crate::ext::mbe::macro_parser::{MatchedNonterminal, MatchedSeq, NamedParseResult};
+use crate::ext::mbe::transcribe::transcribe;
 use crate::feature_gate::Features;
 use crate::parse::parser::Parser;
 use crate::parse::token::TokenKind::*;
@@ -35,7 +35,7 @@ const VALID_FRAGMENT_NAMES_MSG: &str = "valid fragment specifiers are \
                                         `ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, \
                                         `literal`, `path`, `meta`, `tt`, `item` and `vis`";
 
-pub struct ParserAnyMacro<'a> {
+crate struct ParserAnyMacro<'a> {
     parser: Parser<'a>,
 
     /// Span of the expansion site of the macro this parser is for
@@ -45,7 +45,11 @@ pub struct ParserAnyMacro<'a> {
     arm_span: Span,
 }
 
-pub fn annotate_err_with_kind(err: &mut DiagnosticBuilder<'_>, kind: AstFragmentKind, span: Span) {
+crate fn annotate_err_with_kind(
+    err: &mut DiagnosticBuilder<'_>,
+    kind: AstFragmentKind,
+    span: Span,
+) {
     match kind {
         AstFragmentKind::Ty => {
             err.span_label(span, "this macro call doesn't expand to a type");
@@ -58,7 +62,7 @@ pub fn annotate_err_with_kind(err: &mut DiagnosticBuilder<'_>, kind: AstFragment
 }
 
 impl<'a> ParserAnyMacro<'a> {
-    pub fn make(mut self: Box<ParserAnyMacro<'a>>, kind: AstFragmentKind) -> AstFragment {
+    crate fn make(mut self: Box<ParserAnyMacro<'a>>, kind: AstFragmentKind) -> AstFragment {
         let ParserAnyMacro { site_span, macro_ident, ref mut parser, arm_span } = *self;
         let fragment = panictry!(parser.parse_ast_fragment(kind, true).map_err(|mut e| {
             if parser.token == token::Eof && e.message().ends_with(", found `<eof>`") {
@@ -131,8 +135,8 @@ struct MacroRulesMacroExpander {
     name: ast::Ident,
     span: Span,
     transparency: Transparency,
-    lhses: Vec<quoted::TokenTree>,
-    rhses: Vec<quoted::TokenTree>,
+    lhses: Vec<mbe::TokenTree>,
+    rhses: Vec<mbe::TokenTree>,
     valid: bool,
 }
 
@@ -165,8 +169,8 @@ fn generic_extension<'cx>(
     name: ast::Ident,
     transparency: Transparency,
     arg: TokenStream,
-    lhses: &[quoted::TokenTree],
-    rhses: &[quoted::TokenTree],
+    lhses: &[mbe::TokenTree],
+    rhses: &[mbe::TokenTree],
 ) -> Box<dyn MacResult + 'cx> {
     if cx.trace_macros() {
         trace_macros_note(cx, sp, format!("expanding `{}! {{ {} }}`", name, arg));
@@ -178,7 +182,7 @@ fn generic_extension<'cx>(
     for (i, lhs) in lhses.iter().enumerate() {
         // try each arm's matchers
         let lhs_tt = match *lhs {
-            quoted::TokenTree::Delimited(_, ref delim) => &delim.tts[..],
+            mbe::TokenTree::Delimited(_, ref delim) => &delim.tts[..],
             _ => cx.span_bug(sp, "malformed macro lhs"),
         };
 
@@ -186,7 +190,7 @@ fn generic_extension<'cx>(
             Success(named_matches) => {
                 let rhs = match rhses[i] {
                     // ignore delimiters
-                    quoted::TokenTree::Delimited(_, ref delimed) => delimed.tts.clone(),
+                    mbe::TokenTree::Delimited(_, ref delimed) => delimed.tts.clone(),
                     _ => cx.span_bug(sp, "malformed macro rhs"),
                 };
                 let arm_span = rhses[i].span();
@@ -254,7 +258,7 @@ fn generic_extension<'cx>(
         for lhs in lhses {
             // try each arm's matchers
             let lhs_tt = match *lhs {
-                quoted::TokenTree::Delimited(_, ref delim) => &delim.tts[..],
+                mbe::TokenTree::Delimited(_, ref delim) => &delim.tts[..],
                 _ => continue,
             };
             match TokenTree::parse(cx, lhs_tt, arg.clone()) {
@@ -284,8 +288,8 @@ fn generic_extension<'cx>(
 //
 // Holy self-referential!
 
-/// Converts a `macro_rules!` invocation into a syntax extension.
-pub fn compile(
+/// Converts a macro item into a syntax extension.
+pub fn compile_declarative_macro(
     sess: &ParseSess,
     features: &Features,
     def: &ast::Item,
@@ -308,32 +312,32 @@ pub fn compile(
     // ...quasiquoting this would be nice.
     // These spans won't matter, anyways
     let argument_gram = vec![
-        quoted::TokenTree::Sequence(
+        mbe::TokenTree::Sequence(
             DelimSpan::dummy(),
-            Lrc::new(quoted::SequenceRepetition {
+            Lrc::new(mbe::SequenceRepetition {
                 tts: vec![
-                    quoted::TokenTree::MetaVarDecl(def.span, lhs_nm, tt_spec),
-                    quoted::TokenTree::token(token::FatArrow, def.span),
-                    quoted::TokenTree::MetaVarDecl(def.span, rhs_nm, tt_spec),
+                    mbe::TokenTree::MetaVarDecl(def.span, lhs_nm, tt_spec),
+                    mbe::TokenTree::token(token::FatArrow, def.span),
+                    mbe::TokenTree::MetaVarDecl(def.span, rhs_nm, tt_spec),
                 ],
                 separator: Some(Token::new(
                     if body.legacy { token::Semi } else { token::Comma },
                     def.span,
                 )),
-                kleene: quoted::KleeneToken::new(quoted::KleeneOp::OneOrMore, def.span),
+                kleene: mbe::KleeneToken::new(mbe::KleeneOp::OneOrMore, def.span),
                 num_captures: 2,
             }),
         ),
         // to phase into semicolon-termination instead of semicolon-separation
-        quoted::TokenTree::Sequence(
+        mbe::TokenTree::Sequence(
             DelimSpan::dummy(),
-            Lrc::new(quoted::SequenceRepetition {
-                tts: vec![quoted::TokenTree::token(
+            Lrc::new(mbe::SequenceRepetition {
+                tts: vec![mbe::TokenTree::token(
                     if body.legacy { token::Semi } else { token::Comma },
                     def.span,
                 )],
                 separator: None,
-                kleene: quoted::KleeneToken::new(quoted::KleeneOp::ZeroOrMore, def.span),
+                kleene: mbe::KleeneToken::new(mbe::KleeneOp::ZeroOrMore, def.span),
                 num_captures: 0,
             }),
         ),
@@ -363,7 +367,7 @@ pub fn compile(
             .map(|m| {
                 if let MatchedNonterminal(ref nt) = *m {
                     if let NtTT(ref tt) = **nt {
-                        let tt = quoted::parse(
+                        let tt = mbe::quoted::parse(
                             tt.clone().into(),
                             true,
                             sess,
@@ -380,7 +384,7 @@ pub fn compile(
                 }
                 sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs")
             })
-            .collect::<Vec<quoted::TokenTree>>(),
+            .collect::<Vec<mbe::TokenTree>>(),
         _ => sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs"),
     };
 
@@ -390,7 +394,7 @@ pub fn compile(
             .map(|m| {
                 if let MatchedNonterminal(ref nt) = *m {
                     if let NtTT(ref tt) = **nt {
-                        return quoted::parse(
+                        return mbe::quoted::parse(
                             tt.clone().into(),
                             false,
                             sess,
@@ -405,7 +409,7 @@ pub fn compile(
                 }
                 sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs")
             })
-            .collect::<Vec<quoted::TokenTree>>(),
+            .collect::<Vec<mbe::TokenTree>>(),
         _ => sess.span_diagnostic.span_bug(def.span, "wrong-structured rhs"),
     };
 
@@ -450,11 +454,11 @@ fn check_lhs_nt_follows(
     sess: &ParseSess,
     features: &Features,
     attrs: &[ast::Attribute],
-    lhs: &quoted::TokenTree,
+    lhs: &mbe::TokenTree,
 ) -> bool {
     // lhs is going to be like TokenTree::Delimited(...), where the
     // entire lhs is those tts. Or, it can be a "bare sequence", not wrapped in parens.
-    if let quoted::TokenTree::Delimited(_, ref tts) = *lhs {
+    if let mbe::TokenTree::Delimited(_, ref tts) = *lhs {
         check_matcher(sess, features, attrs, &tts.tts)
     } else {
         let msg = "invalid macro matcher; matchers must be contained in balanced delimiters";
@@ -467,8 +471,8 @@ fn check_lhs_nt_follows(
 
 /// Checks that the lhs contains no repetition which could match an empty token
 /// tree, because then the matcher would hang indefinitely.
-fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[quoted::TokenTree]) -> bool {
-    use quoted::TokenTree;
+fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[mbe::TokenTree]) -> bool {
+    use mbe::TokenTree;
     for tt in tts {
         match *tt {
             TokenTree::Token(..) | TokenTree::MetaVar(..) | TokenTree::MetaVarDecl(..) => (),
@@ -482,8 +486,8 @@ fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[quoted::TokenTree]) -> bool {
                     && seq.tts.iter().all(|seq_tt| match *seq_tt {
                         TokenTree::MetaVarDecl(_, _, id) => id.name == sym::vis,
                         TokenTree::Sequence(_, ref sub_seq) => {
-                            sub_seq.kleene.op == quoted::KleeneOp::ZeroOrMore
-                                || sub_seq.kleene.op == quoted::KleeneOp::ZeroOrOne
+                            sub_seq.kleene.op == mbe::KleeneOp::ZeroOrMore
+                                || sub_seq.kleene.op == mbe::KleeneOp::ZeroOrOne
                         }
                         _ => false,
                     })
@@ -502,9 +506,9 @@ fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[quoted::TokenTree]) -> bool {
     true
 }
 
-fn check_rhs(sess: &ParseSess, rhs: &quoted::TokenTree) -> bool {
+fn check_rhs(sess: &ParseSess, rhs: &mbe::TokenTree) -> bool {
     match *rhs {
-        quoted::TokenTree::Delimited(..) => return true,
+        mbe::TokenTree::Delimited(..) => return true,
         _ => sess.span_diagnostic.span_err(rhs.span(), "macro rhs must be delimited"),
     }
     false
@@ -514,7 +518,7 @@ fn check_matcher(
     sess: &ParseSess,
     features: &Features,
     attrs: &[ast::Attribute],
-    matcher: &[quoted::TokenTree],
+    matcher: &[mbe::TokenTree],
 ) -> bool {
     let first_sets = FirstSets::new(matcher);
     let empty_suffix = TokenSet::empty();
@@ -546,8 +550,8 @@ struct FirstSets {
 }
 
 impl FirstSets {
-    fn new(tts: &[quoted::TokenTree]) -> FirstSets {
-        use quoted::TokenTree;
+    fn new(tts: &[mbe::TokenTree]) -> FirstSets {
+        use mbe::TokenTree;
 
         let mut sets = FirstSets { first: FxHashMap::default() };
         build_recur(&mut sets, tts);
@@ -594,8 +598,8 @@ impl FirstSets {
 
                         // Reverse scan: Sequence comes before `first`.
                         if subfirst.maybe_empty
-                            || seq_rep.kleene.op == quoted::KleeneOp::ZeroOrMore
-                            || seq_rep.kleene.op == quoted::KleeneOp::ZeroOrOne
+                            || seq_rep.kleene.op == mbe::KleeneOp::ZeroOrMore
+                            || seq_rep.kleene.op == mbe::KleeneOp::ZeroOrOne
                         {
                             // If sequence is potentially empty, then
                             // union them (preserving first emptiness).
@@ -615,8 +619,8 @@ impl FirstSets {
 
     // walks forward over `tts` until all potential FIRST tokens are
     // identified.
-    fn first(&self, tts: &[quoted::TokenTree]) -> TokenSet {
-        use quoted::TokenTree;
+    fn first(&self, tts: &[mbe::TokenTree]) -> TokenSet {
+        use mbe::TokenTree;
 
         let mut first = TokenSet::empty();
         for tt in tts.iter() {
@@ -652,8 +656,8 @@ impl FirstSets {
                     assert!(first.maybe_empty);
                     first.add_all(subfirst);
                     if subfirst.maybe_empty
-                        || seq_rep.kleene.op == quoted::KleeneOp::ZeroOrMore
-                        || seq_rep.kleene.op == quoted::KleeneOp::ZeroOrOne
+                        || seq_rep.kleene.op == mbe::KleeneOp::ZeroOrMore
+                        || seq_rep.kleene.op == mbe::KleeneOp::ZeroOrOne
                     {
                         // Continue scanning for more first
                         // tokens, but also make sure we
@@ -674,7 +678,7 @@ impl FirstSets {
     }
 }
 
-// A set of `quoted::TokenTree`s, which may include `TokenTree::Match`s
+// A set of `mbe::TokenTree`s, which may include `TokenTree::Match`s
 // (for macro-by-example syntactic variables). It also carries the
 // `maybe_empty` flag; that is true if and only if the matcher can
 // match an empty token sequence.
@@ -686,7 +690,7 @@ impl FirstSets {
 // (Notably, we must allow for *-op to occur zero times.)
 #[derive(Clone, Debug)]
 struct TokenSet {
-    tokens: Vec<quoted::TokenTree>,
+    tokens: Vec<mbe::TokenTree>,
     maybe_empty: bool,
 }
 
@@ -698,13 +702,13 @@ impl TokenSet {
 
     // Returns the set `{ tok }` for the single-token (and thus
     // non-empty) sequence [tok].
-    fn singleton(tok: quoted::TokenTree) -> Self {
+    fn singleton(tok: mbe::TokenTree) -> Self {
         TokenSet { tokens: vec![tok], maybe_empty: false }
     }
 
     // Changes self to be the set `{ tok }`.
     // Since `tok` is always present, marks self as non-empty.
-    fn replace_with(&mut self, tok: quoted::TokenTree) {
+    fn replace_with(&mut self, tok: mbe::TokenTree) {
         self.tokens.clear();
         self.tokens.push(tok);
         self.maybe_empty = false;
@@ -719,7 +723,7 @@ impl TokenSet {
     }
 
     // Adds `tok` to the set for `self`, marking sequence as non-empy.
-    fn add_one(&mut self, tok: quoted::TokenTree) {
+    fn add_one(&mut self, tok: mbe::TokenTree) {
         if !self.tokens.contains(&tok) {
             self.tokens.push(tok);
         }
@@ -727,7 +731,7 @@ impl TokenSet {
     }
 
     // Adds `tok` to the set for `self`. (Leaves `maybe_empty` flag alone.)
-    fn add_one_maybe(&mut self, tok: quoted::TokenTree) {
+    fn add_one_maybe(&mut self, tok: mbe::TokenTree) {
         if !self.tokens.contains(&tok) {
             self.tokens.push(tok);
         }
@@ -768,10 +772,10 @@ fn check_matcher_core(
     features: &Features,
     attrs: &[ast::Attribute],
     first_sets: &FirstSets,
-    matcher: &[quoted::TokenTree],
+    matcher: &[mbe::TokenTree],
     follow: &TokenSet,
 ) -> TokenSet {
-    use quoted::TokenTree;
+    use mbe::TokenTree;
 
     let mut last = TokenSet::empty();
 
@@ -946,8 +950,8 @@ fn check_matcher_core(
     last
 }
 
-fn token_can_be_followed_by_any(tok: &quoted::TokenTree) -> bool {
-    if let quoted::TokenTree::MetaVarDecl(_, _, frag_spec) = *tok {
+fn token_can_be_followed_by_any(tok: &mbe::TokenTree) -> bool {
+    if let mbe::TokenTree::MetaVarDecl(_, _, frag_spec) = *tok {
         frag_can_be_followed_by_any(frag_spec.name)
     } else {
         // (Non NT's can always be followed by anthing in matchers.)
@@ -993,8 +997,8 @@ enum IsInFollow {
 /// break macros that were relying on that binary operator as a
 /// separator.
 // when changing this do not forget to update doc/book/macros.md!
-fn is_in_follow(tok: &quoted::TokenTree, frag: Symbol) -> IsInFollow {
-    use quoted::TokenTree;
+fn is_in_follow(tok: &mbe::TokenTree, frag: Symbol) -> IsInFollow {
+    use mbe::TokenTree;
 
     if let TokenTree::Token(Token { kind: token::CloseDelim(_), .. }) = *tok {
         // closing a token tree can never be matched by any fragment;
@@ -1112,10 +1116,10 @@ fn has_legal_fragment_specifier(
     sess: &ParseSess,
     features: &Features,
     attrs: &[ast::Attribute],
-    tok: &quoted::TokenTree,
+    tok: &mbe::TokenTree,
 ) -> Result<(), String> {
     debug!("has_legal_fragment_specifier({:?})", tok);
-    if let quoted::TokenTree::MetaVarDecl(_, _, ref frag_spec) = *tok {
+    if let mbe::TokenTree::MetaVarDecl(_, _, ref frag_spec) = *tok {
         let frag_span = tok.span();
         if !is_legal_fragment_specifier(sess, features, attrs, frag_spec.name, frag_span) {
             return Err(frag_spec.to_string());
@@ -1156,14 +1160,27 @@ fn is_legal_fragment_specifier(
     }
 }
 
-fn quoted_tt_to_string(tt: &quoted::TokenTree) -> String {
+fn quoted_tt_to_string(tt: &mbe::TokenTree) -> String {
     match *tt {
-        quoted::TokenTree::Token(ref token) => crate::print::pprust::token_to_string(&token),
-        quoted::TokenTree::MetaVar(_, name) => format!("${}", name),
-        quoted::TokenTree::MetaVarDecl(_, name, kind) => format!("${}:{}", name, kind),
+        mbe::TokenTree::Token(ref token) => crate::print::pprust::token_to_string(&token),
+        mbe::TokenTree::MetaVar(_, name) => format!("${}", name),
+        mbe::TokenTree::MetaVarDecl(_, name, kind) => format!("${}:{}", name, kind),
         _ => panic!(
-            "unexpected quoted::TokenTree::{{Sequence or Delimited}} \
+            "unexpected mbe::TokenTree::{{Sequence or Delimited}} \
              in follow set checker"
         ),
     }
 }
+
+impl TokenTree {
+    /// Use this token tree as a matcher to parse given tts.
+    fn parse(cx: &ExtCtxt<'_>, mtch: &[mbe::TokenTree], tts: TokenStream)
+             -> NamedParseResult {
+        // `None` is because we're not interpolating
+        let directory = Directory {
+            path: Cow::from(cx.current_expansion.module.directory.as_path()),
+            ownership: cx.current_expansion.directory_ownership,
+        };
+        parse(cx.parse_sess(), tts, mtch, Some(directory), true)
+    }
+}
diff --git a/src/libsyntax/ext/tt/quoted.rs b/src/libsyntax/ext/mbe/quoted.rs
similarity index 67%
rename from src/libsyntax/ext/tt/quoted.rs
rename to src/libsyntax/ext/mbe/quoted.rs
index cad94a0e4c120..3952e29a5f0d1 100644
--- a/src/libsyntax/ext/tt/quoted.rs
+++ b/src/libsyntax/ext/mbe/quoted.rs
@@ -1,179 +1,19 @@
 use crate::ast;
 use crate::ast::NodeId;
-use crate::ext::tt::macro_parser;
+use crate::ext::mbe::macro_parser;
+use crate::ext::mbe::{TokenTree, KleeneOp, KleeneToken, SequenceRepetition, Delimited};
 use crate::feature_gate::Features;
-use crate::parse::token::{self, Token, TokenKind};
+use crate::parse::token::{self, Token};
 use crate::parse::ParseSess;
 use crate::print::pprust;
 use crate::symbol::kw;
-use crate::tokenstream::{self, DelimSpan};
+use crate::tokenstream;
 
-use syntax_pos::{edition::Edition, BytePos, Span};
+use syntax_pos::{edition::Edition, Span};
 
 use rustc_data_structures::sync::Lrc;
 use std::iter::Peekable;
 
-/// Contains the sub-token-trees of a "delimited" token tree, such as the contents of `(`. Note
-/// that the delimiter itself might be `NoDelim`.
-#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
-pub struct Delimited {
-    pub delim: token::DelimToken,
-    pub tts: Vec<TokenTree>,
-}
-
-impl Delimited {
-    /// Returns a `self::TokenTree` with a `Span` corresponding to the opening delimiter.
-    pub fn open_tt(&self, span: Span) -> TokenTree {
-        let open_span = if span.is_dummy() {
-            span
-        } else {
-            span.with_hi(span.lo() + BytePos(self.delim.len() as u32))
-        };
-        TokenTree::token(token::OpenDelim(self.delim), open_span)
-    }
-
-    /// Returns a `self::TokenTree` with a `Span` corresponding to the closing delimiter.
-    pub fn close_tt(&self, span: Span) -> TokenTree {
-        let close_span = if span.is_dummy() {
-            span
-        } else {
-            span.with_lo(span.hi() - BytePos(self.delim.len() as u32))
-        };
-        TokenTree::token(token::CloseDelim(self.delim), close_span)
-    }
-}
-
-#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug)]
-pub struct SequenceRepetition {
-    /// The sequence of token trees
-    pub tts: Vec<TokenTree>,
-    /// The optional separator
-    pub separator: Option<Token>,
-    /// Whether the sequence can be repeated zero (*), or one or more times (+)
-    pub kleene: KleeneToken,
-    /// The number of `Match`s that appear in the sequence (and subsequences)
-    pub num_captures: usize,
-}
-
-#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Debug, Copy)]
-pub struct KleeneToken {
-    pub span: Span,
-    pub op: KleeneOp,
-}
-
-impl KleeneToken {
-    pub fn new(op: KleeneOp, span: Span) -> KleeneToken {
-        KleeneToken { span, op }
-    }
-}
-
-/// A Kleene-style [repetition operator](http://en.wikipedia.org/wiki/Kleene_star)
-/// for token sequences.
-#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
-pub enum KleeneOp {
-    /// Kleene star (`*`) for zero or more repetitions
-    ZeroOrMore,
-    /// Kleene plus (`+`) for one or more repetitions
-    OneOrMore,
-    /// Kleene optional (`?`) for zero or one reptitions
-    ZeroOrOne,
-}
-
-/// Similar to `tokenstream::TokenTree`, except that `$i`, `$i:ident`, and `$(...)`
-/// are "first-class" token trees. Useful for parsing macros.
-#[derive(Debug, Clone, PartialEq, RustcEncodable, RustcDecodable)]
-pub enum TokenTree {
-    Token(Token),
-    Delimited(DelimSpan, Lrc<Delimited>),
-    /// A kleene-style repetition sequence
-    Sequence(DelimSpan, Lrc<SequenceRepetition>),
-    /// e.g., `$var`
-    MetaVar(Span, ast::Ident),
-    /// e.g., `$var:expr`. This is only used in the left hand side of MBE macros.
-    MetaVarDecl(
-        Span,
-        ast::Ident, /* name to bind */
-        ast::Ident, /* kind of nonterminal */
-    ),
-}
-
-impl TokenTree {
-    /// Return the number of tokens in the tree.
-    pub fn len(&self) -> usize {
-        match *self {
-            TokenTree::Delimited(_, ref delimed) => match delimed.delim {
-                token::NoDelim => delimed.tts.len(),
-                _ => delimed.tts.len() + 2,
-            },
-            TokenTree::Sequence(_, ref seq) => seq.tts.len(),
-            _ => 0,
-        }
-    }
-
-    /// Returns `true` if the given token tree contains no other tokens. This is vacuously true for
-    /// single tokens or metavar/decls, but may be false for delimited trees or sequences.
-    pub fn is_empty(&self) -> bool {
-        match *self {
-            TokenTree::Delimited(_, ref delimed) => match delimed.delim {
-                token::NoDelim => delimed.tts.is_empty(),
-                _ => false,
-            },
-            TokenTree::Sequence(_, ref seq) => seq.tts.is_empty(),
-            _ => true,
-        }
-    }
-
-    /// Returns `true` if the given token tree is delimited.
-    pub fn is_delimited(&self) -> bool {
-        match *self {
-            TokenTree::Delimited(..) => true,
-            _ => false,
-        }
-    }
-
-    /// Returns `true` if the given token tree is a token of the given kind.
-    pub fn is_token(&self, expected_kind: &TokenKind) -> bool {
-        match self {
-            TokenTree::Token(Token { kind: actual_kind, .. }) => actual_kind == expected_kind,
-            _ => false,
-        }
-    }
-
-    /// Gets the `index`-th sub-token-tree. This only makes sense for delimited trees and sequences.
-    pub fn get_tt(&self, index: usize) -> TokenTree {
-        match (self, index) {
-            (&TokenTree::Delimited(_, ref delimed), _) if delimed.delim == token::NoDelim => {
-                delimed.tts[index].clone()
-            }
-            (&TokenTree::Delimited(span, ref delimed), _) => {
-                if index == 0 {
-                    return delimed.open_tt(span.open);
-                }
-                if index == delimed.tts.len() + 1 {
-                    return delimed.close_tt(span.close);
-                }
-                delimed.tts[index - 1].clone()
-            }
-            (&TokenTree::Sequence(_, ref seq), _) => seq.tts[index].clone(),
-            _ => panic!("Cannot expand a token tree"),
-        }
-    }
-
-    /// Retrieves the `TokenTree`'s span.
-    pub fn span(&self) -> Span {
-        match *self {
-            TokenTree::Token(Token { span, .. })
-            | TokenTree::MetaVar(span, _)
-            | TokenTree::MetaVarDecl(span, _, _) => span,
-            TokenTree::Delimited(span, _) | TokenTree::Sequence(span, _) => span.entire(),
-        }
-    }
-
-    crate fn token(kind: TokenKind, span: Span) -> TokenTree {
-        TokenTree::Token(Token::new(kind, span))
-    }
-}
-
 /// Takes a `tokenstream::TokenStream` and returns a `Vec<self::TokenTree>`. Specifically, this
 /// takes a generic `TokenStream`, such as is used in the rest of the compiler, and returns a
 /// collection of `TokenTree` for use in parsing a macro.
@@ -195,7 +35,7 @@ impl TokenTree {
 /// # Returns
 ///
 /// A collection of `self::TokenTree`. There may also be some errors emitted to `sess`.
-pub fn parse(
+pub(super) fn parse(
     input: tokenstream::TokenStream,
     expect_matchers: bool,
     sess: &ParseSess,
diff --git a/src/libsyntax/ext/tt/transcribe.rs b/src/libsyntax/ext/mbe/transcribe.rs
similarity index 93%
rename from src/libsyntax/ext/tt/transcribe.rs
rename to src/libsyntax/ext/mbe/transcribe.rs
index f9c07e3a2e4ff..ba818ebd35c7f 100644
--- a/src/libsyntax/ext/tt/transcribe.rs
+++ b/src/libsyntax/ext/mbe/transcribe.rs
@@ -1,7 +1,7 @@
 use crate::ast::{Ident, Mac};
 use crate::ext::base::ExtCtxt;
-use crate::ext::tt::macro_parser::{MatchedNonterminal, MatchedSeq, NamedMatch};
-use crate::ext::tt::quoted;
+use crate::ext::mbe;
+use crate::ext::mbe::macro_parser::{MatchedNonterminal, MatchedSeq, NamedMatch};
 use crate::mut_visit::{self, MutVisitor};
 use crate::parse::token::{self, NtTT, Token};
 use crate::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndJoint};
@@ -38,22 +38,22 @@ impl Marker {
 
 /// An iterator over the token trees in a delimited token tree (`{ ... }`) or a sequence (`$(...)`).
 enum Frame {
-    Delimited { forest: Lrc<quoted::Delimited>, idx: usize, span: DelimSpan },
-    Sequence { forest: Lrc<quoted::SequenceRepetition>, idx: usize, sep: Option<Token> },
+    Delimited { forest: Lrc<mbe::Delimited>, idx: usize, span: DelimSpan },
+    Sequence { forest: Lrc<mbe::SequenceRepetition>, idx: usize, sep: Option<Token> },
 }
 
 impl Frame {
     /// Construct a new frame around the delimited set of tokens.
-    fn new(tts: Vec<quoted::TokenTree>) -> Frame {
-        let forest = Lrc::new(quoted::Delimited { delim: token::NoDelim, tts });
+    fn new(tts: Vec<mbe::TokenTree>) -> Frame {
+        let forest = Lrc::new(mbe::Delimited { delim: token::NoDelim, tts });
         Frame::Delimited { forest, idx: 0, span: DelimSpan::dummy() }
     }
 }
 
 impl Iterator for Frame {
-    type Item = quoted::TokenTree;
+    type Item = mbe::TokenTree;
 
-    fn next(&mut self) -> Option<quoted::TokenTree> {
+    fn next(&mut self) -> Option<mbe::TokenTree> {
         match *self {
             Frame::Delimited { ref forest, ref mut idx, .. } => {
                 *idx += 1;
@@ -90,7 +90,7 @@ impl Iterator for Frame {
 pub(super) fn transcribe(
     cx: &ExtCtxt<'_>,
     interp: &FxHashMap<Ident, NamedMatch>,
-    src: Vec<quoted::TokenTree>,
+    src: Vec<mbe::TokenTree>,
     transparency: Transparency,
 ) -> TokenStream {
     // Nothing for us to transcribe...
@@ -178,7 +178,7 @@ pub(super) fn transcribe(
             // We are descending into a sequence. We first make sure that the matchers in the RHS
             // and the matches in `interp` have the same shape. Otherwise, either the caller or the
             // macro writer has made a mistake.
-            seq @ quoted::TokenTree::Sequence(..) => {
+            seq @ mbe::TokenTree::Sequence(..) => {
                 match lockstep_iter_size(&seq, interp, &repeats) {
                     LockstepIterSize::Unconstrained => {
                         cx.span_fatal(
@@ -199,7 +199,7 @@ pub(super) fn transcribe(
                     LockstepIterSize::Constraint(len, _) => {
                         // We do this to avoid an extra clone above. We know that this is a
                         // sequence already.
-                        let (sp, seq) = if let quoted::TokenTree::Sequence(sp, seq) = seq {
+                        let (sp, seq) = if let mbe::TokenTree::Sequence(sp, seq) = seq {
                             (sp, seq)
                         } else {
                             unreachable!()
@@ -207,7 +207,7 @@ pub(super) fn transcribe(
 
                         // Is the repetition empty?
                         if len == 0 {
-                            if seq.kleene.op == quoted::KleeneOp::OneOrMore {
+                            if seq.kleene.op == mbe::KleeneOp::OneOrMore {
                                 // FIXME: this really ought to be caught at macro definition
                                 // time... It happens when the Kleene operator in the matcher and
                                 // the body for the same meta-variable do not match.
@@ -232,7 +232,7 @@ pub(super) fn transcribe(
             }
 
             // Replace the meta-var with the matched token tree from the invocation.
-            quoted::TokenTree::MetaVar(mut sp, mut ident) => {
+            mbe::TokenTree::MetaVar(mut sp, mut ident) => {
                 // Find the matched nonterminal from the macro invocation, and use it to replace
                 // the meta-var.
                 if let Some(cur_matched) = lookup_cur_matched(ident, interp, &repeats) {
@@ -269,7 +269,7 @@ pub(super) fn transcribe(
             // We will produce all of the results of the inside of the `Delimited` and then we will
             // jump back out of the Delimited, pop the result_stack and add the new results back to
             // the previous results (from outside the Delimited).
-            quoted::TokenTree::Delimited(mut span, delimited) => {
+            mbe::TokenTree::Delimited(mut span, delimited) => {
                 marker.visit_delim_span(&mut span);
                 stack.push(Frame::Delimited { forest: delimited, idx: 0, span });
                 result_stack.push(mem::take(&mut result));
@@ -277,14 +277,14 @@ pub(super) fn transcribe(
 
             // Nothing much to do here. Just push the token to the result, being careful to
             // preserve syntax context.
-            quoted::TokenTree::Token(token) => {
+            mbe::TokenTree::Token(token) => {
                 let mut tt = TokenTree::Token(token);
                 marker.visit_tt(&mut tt);
                 result.push(tt.into());
             }
 
             // There should be no meta-var declarations in the invocation of a macro.
-            quoted::TokenTree::MetaVarDecl(..) => panic!("unexpected `TokenTree::MetaVarDecl"),
+            mbe::TokenTree::MetaVarDecl(..) => panic!("unexpected `TokenTree::MetaVarDecl"),
         }
     }
 }
@@ -368,11 +368,11 @@ impl LockstepIterSize {
 /// `lookup_cur_matched` will return `None`, which is why this still works even in the presnece of
 /// multiple nested matcher sequences.
 fn lockstep_iter_size(
-    tree: &quoted::TokenTree,
+    tree: &mbe::TokenTree,
     interpolations: &FxHashMap<Ident, NamedMatch>,
     repeats: &[(usize, usize)],
 ) -> LockstepIterSize {
-    use quoted::TokenTree;
+    use mbe::TokenTree;
     match *tree {
         TokenTree::Delimited(_, ref delimed) => {
             delimed.tts.iter().fold(LockstepIterSize::Unconstrained, |size, tt| {
diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index b4ae1e87bca28..b0833010fe071 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -162,19 +162,14 @@ pub mod ext {
     mod proc_macro_server;
 
     pub use syntax_pos::hygiene;
+    pub use mbe::macro_rules::compile_declarative_macro;
     pub mod allocator;
     pub mod base;
     pub mod build;
     pub mod expand;
     pub mod proc_macro;
 
-    pub mod tt {
-        pub mod transcribe;
-        pub mod macro_check;
-        pub mod macro_parser;
-        pub mod macro_rules;
-        pub mod quoted;
-    }
+    crate mod mbe;
 }
 
 pub mod early_buffered_lints;
diff --git a/src/libsyntax/tokenstream.rs b/src/libsyntax/tokenstream.rs
index d702038f54ec3..26cae2a8e7c42 100644
--- a/src/libsyntax/tokenstream.rs
+++ b/src/libsyntax/tokenstream.rs
@@ -13,9 +13,6 @@
 //! and a borrowed `TokenStream` is sufficient to build an owned `TokenStream` without taking
 //! ownership of the original.
 
-use crate::ext::base;
-use crate::ext::tt::{macro_parser, quoted};
-use crate::parse::Directory;
 use crate::parse::token::{self, DelimToken, Token, TokenKind};
 use crate::print::pprust;
 
@@ -26,7 +23,6 @@ use rustc_data_structures::sync::Lrc;
 use rustc_serialize::{Decoder, Decodable, Encoder, Encodable};
 use smallvec::{SmallVec, smallvec};
 
-use std::borrow::Cow;
 use std::{fmt, iter, mem};
 
 #[cfg(test)]
@@ -63,17 +59,6 @@ where
 {}
 
 impl TokenTree {
-    /// Use this token tree as a matcher to parse given tts.
-    pub fn parse(cx: &base::ExtCtxt<'_>, mtch: &[quoted::TokenTree], tts: TokenStream)
-                 -> macro_parser::NamedParseResult {
-        // `None` is because we're not interpolating
-        let directory = Directory {
-            path: Cow::from(cx.current_expansion.module.directory.as_path()),
-            ownership: cx.current_expansion.directory_ownership,
-        };
-        macro_parser::parse(cx.parse_sess(), tts, mtch, Some(directory), true)
-    }
-
     /// Checks if this TokenTree is equal to the other, regardless of span information.
     pub fn eq_unspanned(&self, other: &TokenTree) -> bool {
         match (self, other) {
diff --git a/src/libsyntax_ext/Cargo.toml b/src/libsyntax_ext/Cargo.toml
index 791ee94b4fa77..73310df305b32 100644
--- a/src/libsyntax_ext/Cargo.toml
+++ b/src/libsyntax_ext/Cargo.toml
@@ -18,4 +18,3 @@ rustc_target = { path = "../librustc_target" }
 smallvec = { version = "0.6.7", features = ["union", "may_dangle"] }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
-rustc_lexer = { path = "../librustc_lexer" }
diff --git a/src/libtest/formatters/json.rs b/src/libtest/formatters/json.rs
index e0bea4ce54530..d9e4abf61c3dc 100644
--- a/src/libtest/formatters/json.rs
+++ b/src/libtest/formatters/json.rs
@@ -27,6 +27,7 @@ impl<T: Write> JsonFormatter<T> {
         ty: &str,
         name: &str,
         evt: &str,
+        exec_time: Option<&TestExecTime>,
         stdout: Option<Cow<'_, str>>,
         extra: Option<&str>,
     ) -> io::Result<()> {
@@ -34,6 +35,12 @@ impl<T: Write> JsonFormatter<T> {
             r#"{{ "type": "{}", "name": "{}", "event": "{}""#,
             ty, name, evt
         ))?;
+        if let Some(exec_time) = exec_time {
+            self.write_message(&*format!(
+                r#", "exec_time": "{}""#,
+                exec_time
+            ))?;
+        }
         if let Some(stdout) = stdout {
             self.write_message(&*format!(
                 r#", "stdout": "{}""#,
@@ -69,6 +76,7 @@ impl<T: Write> OutputFormatter for JsonFormatter<T> {
         &mut self,
         desc: &TestDesc,
         result: &TestResult,
+        exec_time: Option<&TestExecTime>,
         stdout: &[u8],
         state: &ConsoleTestState,
     ) -> io::Result<()> {
@@ -78,24 +86,36 @@ impl<T: Write> OutputFormatter for JsonFormatter<T> {
             None
         };
         match *result {
-            TrOk => self.write_event("test", desc.name.as_slice(), "ok", stdout, None),
+            TrOk => {
+                self.write_event("test", desc.name.as_slice(), "ok", exec_time, stdout, None)
+            }
 
-            TrFailed => self.write_event("test", desc.name.as_slice(), "failed", stdout, None),
+            TrFailed => {
+                self.write_event("test", desc.name.as_slice(), "failed", exec_time, stdout, None)
+            }
 
             TrFailedMsg(ref m) => self.write_event(
                 "test",
                 desc.name.as_slice(),
                 "failed",
+                exec_time,
                 stdout,
                 Some(&*format!(r#""message": "{}""#, EscapedString(m))),
             ),
 
-            TrIgnored => self.write_event("test", desc.name.as_slice(), "ignored", stdout, None),
-
-            TrAllowedFail => {
-                self.write_event("test", desc.name.as_slice(), "allowed_failure", stdout, None)
+            TrIgnored => {
+                self.write_event("test", desc.name.as_slice(), "ignored", exec_time, stdout, None)
             }
 
+            TrAllowedFail => self.write_event(
+                "test",
+                desc.name.as_slice(),
+                "allowed_failure",
+                exec_time,
+                stdout,
+                None,
+            ),
+
             TrBench(ref bs) => {
                 let median = bs.ns_iter_summ.median as usize;
                 let deviation = (bs.ns_iter_summ.max - bs.ns_iter_summ.min) as usize;
diff --git a/src/libtest/formatters/mod.rs b/src/libtest/formatters/mod.rs
index cc30b06e5ec38..e97cda76d2318 100644
--- a/src/libtest/formatters/mod.rs
+++ b/src/libtest/formatters/mod.rs
@@ -16,6 +16,7 @@ pub(crate) trait OutputFormatter {
         &mut self,
         desc: &TestDesc,
         result: &TestResult,
+        exec_time: Option<&TestExecTime>,
         stdout: &[u8],
         state: &ConsoleTestState,
     ) -> io::Result<()>;
diff --git a/src/libtest/formatters/pretty.rs b/src/libtest/formatters/pretty.rs
index 88331406a64d0..184726c67d3fb 100644
--- a/src/libtest/formatters/pretty.rs
+++ b/src/libtest/formatters/pretty.rs
@@ -30,20 +30,20 @@ impl<T: Write> PrettyFormatter<T> {
         &self.out
     }
 
-    pub fn write_ok(&mut self) -> io::Result<()> {
-        self.write_short_result("ok", term::color::GREEN)
+    pub fn write_ok(&mut self, exec_time: Option<&TestExecTime>) -> io::Result<()> {
+        self.write_short_result("ok", term::color::GREEN, exec_time)
     }
 
-    pub fn write_failed(&mut self) -> io::Result<()> {
-        self.write_short_result("FAILED", term::color::RED)
+    pub fn write_failed(&mut self, exec_time: Option<&TestExecTime>) -> io::Result<()> {
+        self.write_short_result("FAILED", term::color::RED, exec_time)
     }
 
-    pub fn write_ignored(&mut self) -> io::Result<()> {
-        self.write_short_result("ignored", term::color::YELLOW)
+    pub fn write_ignored(&mut self, exec_time: Option<&TestExecTime>) -> io::Result<()> {
+        self.write_short_result("ignored", term::color::YELLOW, exec_time)
     }
 
-    pub fn write_allowed_fail(&mut self) -> io::Result<()> {
-        self.write_short_result("FAILED (allowed)", term::color::YELLOW)
+    pub fn write_allowed_fail(&mut self, exec_time: Option<&TestExecTime>) -> io::Result<()> {
+        self.write_short_result("FAILED (allowed)", term::color::YELLOW, exec_time)
     }
 
     pub fn write_bench(&mut self) -> io::Result<()> {
@@ -54,8 +54,12 @@ impl<T: Write> PrettyFormatter<T> {
         &mut self,
         result: &str,
         color: term::color::Color,
+        exec_time: Option<&TestExecTime>,
     ) -> io::Result<()> {
         self.write_pretty(result, color)?;
+        if let Some(exec_time) = exec_time {
+            self.write_plain(format!(" {}", exec_time))?;
+        }
         self.write_plain("\n")
     }
 
@@ -166,6 +170,7 @@ impl<T: Write> OutputFormatter for PrettyFormatter<T> {
         &mut self,
         desc: &TestDesc,
         result: &TestResult,
+        exec_time: Option<&TestExecTime>,
         _: &[u8],
         _: &ConsoleTestState,
     ) -> io::Result<()> {
@@ -174,10 +179,10 @@ impl<T: Write> OutputFormatter for PrettyFormatter<T> {
         }
 
         match *result {
-            TrOk => self.write_ok(),
-            TrFailed | TrFailedMsg(_) => self.write_failed(),
-            TrIgnored => self.write_ignored(),
-            TrAllowedFail => self.write_allowed_fail(),
+            TrOk => self.write_ok(exec_time),
+            TrFailed | TrFailedMsg(_) => self.write_failed(exec_time),
+            TrIgnored => self.write_ignored(exec_time),
+            TrAllowedFail => self.write_allowed_fail(exec_time),
             TrBench(ref bs) => {
                 self.write_bench()?;
                 self.write_plain(&format!(": {}\n", fmt_bench_samples(bs)))
diff --git a/src/libtest/formatters/terse.rs b/src/libtest/formatters/terse.rs
index d10b0c5807d57..1812c20904c87 100644
--- a/src/libtest/formatters/terse.rs
+++ b/src/libtest/formatters/terse.rs
@@ -174,6 +174,7 @@ impl<T: Write> OutputFormatter for TerseFormatter<T> {
         &mut self,
         desc: &TestDesc,
         result: &TestResult,
+        _: Option<&TestExecTime>,
         _: &[u8],
         _: &ConsoleTestState,
     ) -> io::Result<()> {
diff --git a/src/libtest/lib.rs b/src/libtest/lib.rs
index 09d5fcc89520e..e441514e59738 100644
--- a/src/libtest/lib.rs
+++ b/src/libtest/lib.rs
@@ -378,6 +378,7 @@ pub struct TestOpts {
     pub format: OutputFormat,
     pub test_threads: Option<usize>,
     pub skip: Vec<String>,
+    pub report_time: bool,
     pub options: Options,
 }
 
@@ -460,6 +461,11 @@ fn optgroups() -> getopts::Options {
             "Enable nightly-only flags:
             unstable-options = Allow use of experimental features",
             "unstable-options",
+        )
+        .optflag(
+            "",
+            "report-time",
+            "Show execution time of each test. Not available for --format=terse"
         );
     return opts;
 }
@@ -560,6 +566,13 @@ pub fn parse_opts(args: &[String]) -> Option<OptRes> {
         ));
     }
 
+    let report_time = matches.opt_present("report-time");
+    if !allow_unstable && report_time {
+        return Some(Err(
+            "The \"report-time\" flag is only accepted on the nightly compiler".into(),
+        ));
+    }
+
     let run_ignored = match (include_ignored, matches.opt_present("ignored")) {
         (true, true) => {
             return Some(Err(
@@ -653,6 +666,7 @@ pub fn parse_opts(args: &[String]) -> Option<OptRes> {
         format,
         test_threads,
         skip: matches.opt_strs("skip"),
+        report_time,
         options: Options::new().display_output(matches.opt_present("show-output")),
     };
 
@@ -677,6 +691,16 @@ pub enum TestResult {
 
 unsafe impl Send for TestResult {}
 
+/// The meassured execution time of a unit test.
+#[derive(Clone, PartialEq)]
+pub struct TestExecTime(Duration);
+
+impl fmt::Display for TestExecTime {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{:.3}s", self.0.as_secs_f64())
+    }
+}
+
 enum OutputLocation<T> {
     Pretty(Box<term::StdoutTerminal>),
     Raw(T),
@@ -736,17 +760,30 @@ impl ConsoleTestState {
         })
     }
 
-    pub fn write_log<S: AsRef<str>>(&mut self, msg: S) -> io::Result<()> {
-        let msg = msg.as_ref();
+    pub fn write_log<F, S>(
+        &mut self,
+        msg: F,
+    ) -> io::Result<()>
+    where
+        S: AsRef<str>,
+        F: FnOnce() -> S,
+    {
         match self.log_out {
             None => Ok(()),
-            Some(ref mut o) => o.write_all(msg.as_bytes()),
+            Some(ref mut o) => {
+                let msg = msg();
+                let msg = msg.as_ref();
+                o.write_all(msg.as_bytes())
+            },
         }
     }
 
-    pub fn write_log_result(&mut self, test: &TestDesc, result: &TestResult) -> io::Result<()> {
-        self.write_log(format!(
-            "{} {}\n",
+    pub fn write_log_result(&mut self,test: &TestDesc,
+        result: &TestResult,
+        exec_time: Option<&TestExecTime>,
+    ) -> io::Result<()> {
+        self.write_log(|| format!(
+            "{} {}",
             match *result {
                 TrOk => "ok".to_owned(),
                 TrFailed => "failed".to_owned(),
@@ -755,8 +792,12 @@ impl ConsoleTestState {
                 TrAllowedFail => "failed (allowed)".to_owned(),
                 TrBench(ref bs) => fmt_bench_samples(bs),
             },
-            test.name
-        ))
+            test.name,
+        ))?;
+        if let Some(exec_time) = exec_time {
+            self.write_log(|| format!(" {}", exec_time))?;
+        }
+        self.write_log(|| "\n")
     }
 
     fn current_test_count(&self) -> usize {
@@ -843,7 +884,7 @@ pub fn list_tests_console(opts: &TestOpts, tests: Vec<TestDescAndFn>) -> io::Res
         };
 
         writeln!(output, "{}: {}", name, fntype)?;
-        st.write_log(format!("{} {}\n", fntype, name))?;
+        st.write_log(|| format!("{} {}\n", fntype, name))?;
     }
 
     fn plural(count: u32, s: &str) -> String {
@@ -884,9 +925,9 @@ pub fn run_tests_console(opts: &TestOpts, tests: Vec<TestDescAndFn>) -> io::Resu
             TeFilteredOut(filtered_out) => Ok(st.filtered_out = filtered_out),
             TeWait(ref test) => out.write_test_start(test),
             TeTimeout(ref test) => out.write_timeout(test),
-            TeResult(test, result, stdout) => {
-                st.write_log_result(&test, &result)?;
-                out.write_result(&test, &result, &*stdout, &st)?;
+            TeResult(test, result, exec_time, stdout) => {
+                st.write_log_result(&test, &result, exec_time.as_ref())?;
+                out.write_result(&test, &result, exec_time.as_ref(), &*stdout, &st)?;
                 match result {
                     TrOk => {
                         st.passed += 1;
@@ -1004,12 +1045,12 @@ fn stdout_isatty() -> bool {
 pub enum TestEvent {
     TeFiltered(Vec<TestDesc>),
     TeWait(TestDesc),
-    TeResult(TestDesc, TestResult, Vec<u8>),
+    TeResult(TestDesc, TestResult, Option<TestExecTime>, Vec<u8>),
     TeTimeout(TestDesc),
     TeFilteredOut(usize),
 }
 
-pub type MonitorMsg = (TestDesc, TestResult, Vec<u8>);
+pub type MonitorMsg = (TestDesc, TestResult, Option<TestExecTime>, Vec<u8>);
 
 struct Sink(Arc<Mutex<Vec<u8>>>);
 impl Write for Sink {
@@ -1105,8 +1146,8 @@ where
             let test = remaining.pop().unwrap();
             callback(TeWait(test.desc.clone()))?;
             run_test(opts, !opts.run_tests, test, tx.clone(), Concurrent::No);
-            let (test, result, stdout) = rx.recv().unwrap();
-            callback(TeResult(test, result, stdout))?;
+            let (test, result, exec_time, stdout) = rx.recv().unwrap();
+            callback(TeResult(test, result, exec_time, stdout))?;
         }
     } else {
         while pending > 0 || !remaining.is_empty() {
@@ -1135,10 +1176,10 @@ where
                 }
             }
 
-            let (desc, result, stdout) = res.unwrap();
+            let (desc, result, exec_time, stdout) = res.unwrap();
             running_tests.remove(&desc);
 
-            callback(TeResult(desc, result, stdout))?;
+            callback(TeResult(desc, result, exec_time, stdout))?;
             pending -= 1;
         }
     }
@@ -1148,8 +1189,8 @@ where
         for b in filtered_benchs {
             callback(TeWait(b.desc.clone()))?;
             run_test(opts, false, b, tx.clone(), Concurrent::No);
-            let (test, result, stdout) = rx.recv().unwrap();
-            callback(TeResult(test, result, stdout))?;
+            let (test, result, exec_time, stdout) = rx.recv().unwrap();
+            callback(TeResult(test, result, exec_time, stdout))?;
         }
     }
     Ok(())
@@ -1384,7 +1425,7 @@ pub fn run_test(
         && desc.should_panic != ShouldPanic::No;
 
     if force_ignore || desc.ignore || ignore_because_panic_abort {
-        monitor_ch.send((desc, TrIgnored, Vec::new())).unwrap();
+        monitor_ch.send((desc, TrIgnored, None, Vec::new())).unwrap();
         return;
     }
 
@@ -1392,6 +1433,7 @@ pub fn run_test(
         desc: TestDesc,
         monitor_ch: Sender<MonitorMsg>,
         nocapture: bool,
+        report_time: bool,
         testfn: Box<dyn FnOnce() + Send>,
         concurrency: Concurrent,
     ) {
@@ -1410,7 +1452,16 @@ pub fn run_test(
                 None
             };
 
+            let start = if report_time {
+                Some(Instant::now())
+            } else {
+                None
+            };
             let result = catch_unwind(AssertUnwindSafe(testfn));
+            let exec_time = start.map(|start| {
+                let duration = start.elapsed();
+                TestExecTime(duration)
+            });
 
             if let Some((printio, panicio)) = oldio {
                 io::set_print(printio);
@@ -1420,7 +1471,7 @@ pub fn run_test(
             let test_result = calc_result(&desc, result);
             let stdout = data.lock().unwrap().to_vec();
             monitor_ch
-                .send((desc.clone(), test_result, stdout))
+                .send((desc.clone(), test_result, exec_time, stdout))
                 .unwrap();
         };
 
@@ -1449,12 +1500,20 @@ pub fn run_test(
         }
         DynTestFn(f) => {
             let cb = move || __rust_begin_short_backtrace(f);
-            run_test_inner(desc, monitor_ch, opts.nocapture, Box::new(cb), concurrency)
+            run_test_inner(
+                desc,
+                monitor_ch,
+                opts.nocapture,
+                opts.report_time,
+                Box::new(cb),
+                concurrency,
+            )
         }
         StaticTestFn(f) => run_test_inner(
             desc,
             monitor_ch,
             opts.nocapture,
+            opts.report_time,
             Box::new(move || __rust_begin_short_backtrace(f)),
             concurrency,
         ),
@@ -1702,7 +1761,7 @@ pub mod bench {
         };
 
         let stdout = data.lock().unwrap().to_vec();
-        monitor_ch.send((desc, test_result, stdout)).unwrap();
+        monitor_ch.send((desc, test_result, None, stdout)).unwrap();
     }
 
     pub fn run_once<F>(f: F)
diff --git a/src/libtest/tests.rs b/src/libtest/tests.rs
index afc4217ec1ba2..13ac8eb91f411 100644
--- a/src/libtest/tests.rs
+++ b/src/libtest/tests.rs
@@ -23,6 +23,7 @@ impl TestOpts {
             format: OutputFormat::Pretty,
             test_threads: None,
             skip: vec![],
+            report_time: false,
             options: Options::new(),
         }
     }
@@ -67,7 +68,7 @@ pub fn do_not_run_ignored_tests() {
     };
     let (tx, rx) = channel();
     run_test(&TestOpts::new(), false, desc, tx, Concurrent::No);
-    let (_, res, _) = rx.recv().unwrap();
+    let (_, res, _, _) = rx.recv().unwrap();
     assert!(res != TrOk);
 }
 
@@ -85,7 +86,7 @@ pub fn ignored_tests_result_in_ignored() {
     };
     let (tx, rx) = channel();
     run_test(&TestOpts::new(), false, desc, tx, Concurrent::No);
-    let (_, res, _) = rx.recv().unwrap();
+    let (_, res, _, _) = rx.recv().unwrap();
     assert!(res == TrIgnored);
 }
 
@@ -105,7 +106,7 @@ fn test_should_panic() {
     };
     let (tx, rx) = channel();
     run_test(&TestOpts::new(), false, desc, tx, Concurrent::No);
-    let (_, res, _) = rx.recv().unwrap();
+    let (_, res, _, _) = rx.recv().unwrap();
     assert!(res == TrOk);
 }
 
@@ -125,7 +126,7 @@ fn test_should_panic_good_message() {
     };
     let (tx, rx) = channel();
     run_test(&TestOpts::new(), false, desc, tx, Concurrent::No);
-    let (_, res, _) = rx.recv().unwrap();
+    let (_, res, _, _) = rx.recv().unwrap();
     assert!(res == TrOk);
 }
 
@@ -147,7 +148,7 @@ fn test_should_panic_bad_message() {
     };
     let (tx, rx) = channel();
     run_test(&TestOpts::new(), false, desc, tx, Concurrent::No);
-    let (_, res, _) = rx.recv().unwrap();
+    let (_, res, _, _) = rx.recv().unwrap();
     assert!(res == TrFailedMsg(format!("{} '{}'", failed_msg, expected)));
 }
 
@@ -165,10 +166,43 @@ fn test_should_panic_but_succeeds() {
     };
     let (tx, rx) = channel();
     run_test(&TestOpts::new(), false, desc, tx, Concurrent::No);
-    let (_, res, _) = rx.recv().unwrap();
+    let (_, res, _, _) = rx.recv().unwrap();
     assert!(res == TrFailed);
 }
 
+fn report_time_test_template(report_time: bool) -> Option<TestExecTime> {
+    fn f() {}
+    let desc = TestDescAndFn {
+        desc: TestDesc {
+            name: StaticTestName("whatever"),
+            ignore: false,
+            should_panic: ShouldPanic::No,
+            allow_fail: false,
+        },
+        testfn: DynTestFn(Box::new(f)),
+    };
+    let test_opts = TestOpts {
+        report_time,
+        ..TestOpts::new()
+    };
+    let (tx, rx) = channel();
+    run_test(&test_opts, false, desc, tx, Concurrent::No);
+    let (_, _, exec_time, _) = rx.recv().unwrap();
+    exec_time
+}
+
+#[test]
+fn test_should_not_report_time() {
+    let exec_time = report_time_test_template(false);
+    assert!(exec_time.is_none());
+}
+
+#[test]
+fn test_should_report_time() {
+    let exec_time = report_time_test_template(true);
+    assert!(exec_time.is_some());
+}
+
 #[test]
 fn parse_ignored_flag() {
     let args = vec![
diff --git a/src/test/ui/borrowck/borrowck-closures-mut-of-imm.rs b/src/test/ui/borrowck/borrowck-closures-mut-of-imm.rs
index 24e06e3c4e666..d7e187a2b3958 100644
--- a/src/test/ui/borrowck/borrowck-closures-mut-of-imm.rs
+++ b/src/test/ui/borrowck/borrowck-closures-mut-of-imm.rs
@@ -1,10 +1,6 @@
 // Tests that two closures cannot simultaneously have mutable
 // and immutable access to the variable. Issue #6801.
 
-fn get(x: &isize) -> isize {
-    *x
-}
-
 fn set(x: &mut isize) {
     *x = 4;
 }
diff --git a/src/test/ui/borrowck/borrowck-closures-mut-of-imm.stderr b/src/test/ui/borrowck/borrowck-closures-mut-of-imm.stderr
index 3be7d725eda3a..784b903a5896a 100644
--- a/src/test/ui/borrowck/borrowck-closures-mut-of-imm.stderr
+++ b/src/test/ui/borrowck/borrowck-closures-mut-of-imm.stderr
@@ -1,17 +1,17 @@
 error[E0596]: cannot borrow `*x` as mutable, as it is behind a `&` reference
-  --> $DIR/borrowck-closures-mut-of-imm.rs:13:25
+  --> $DIR/borrowck-closures-mut-of-imm.rs:9:25
    |
 LL |     let mut c1 = || set(&mut *x);
    |                         ^^^^^^^ cannot borrow as mutable
 
 error[E0596]: cannot borrow `*x` as mutable, as it is behind a `&` reference
-  --> $DIR/borrowck-closures-mut-of-imm.rs:15:25
+  --> $DIR/borrowck-closures-mut-of-imm.rs:11:25
    |
 LL |     let mut c2 = || set(&mut *x);
    |                         ^^^^^^^ cannot borrow as mutable
 
 error[E0524]: two closures require unique access to `x` at the same time
-  --> $DIR/borrowck-closures-mut-of-imm.rs:15:18
+  --> $DIR/borrowck-closures-mut-of-imm.rs:11:18
    |
 LL |     let mut c1 = || set(&mut *x);
    |                  --           - first borrow occurs due to use of `x` in closure
@@ -28,4 +28,5 @@ LL |     c2(); c1();
 
 error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0596`.
+Some errors have detailed explanations: E0524, E0596.
+For more information about an error, try `rustc --explain E0524`.
diff --git a/src/test/ui/borrowck/borrowck-closures-mut-of-mut.stderr b/src/test/ui/borrowck/borrowck-closures-mut-of-mut.stderr
index a174388712158..471173e595f47 100644
--- a/src/test/ui/borrowck/borrowck-closures-mut-of-mut.stderr
+++ b/src/test/ui/borrowck/borrowck-closures-mut-of-mut.stderr
@@ -15,3 +15,4 @@ LL |     c2(); c1();
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0524`.
diff --git a/src/test/ui/borrowck/borrowck-closures-unique.stderr b/src/test/ui/borrowck/borrowck-closures-unique.stderr
index 9b53af4c01f59..2ed08b83c58b9 100644
--- a/src/test/ui/borrowck/borrowck-closures-unique.stderr
+++ b/src/test/ui/borrowck/borrowck-closures-unique.stderr
@@ -50,4 +50,5 @@ LL |     let c1 = |y: &'static mut isize| x = y;
 
 error: aborting due to 4 previous errors
 
-For more information about this error, try `rustc --explain E0500`.
+Some errors have detailed explanations: E0500, E0524.
+For more information about an error, try `rustc --explain E0500`.
diff --git a/src/test/ui/nll/closures-in-loops.stderr b/src/test/ui/nll/closures-in-loops.stderr
index 7603f9650b54a..0b15d9bcfe68c 100644
--- a/src/test/ui/nll/closures-in-loops.stderr
+++ b/src/test/ui/nll/closures-in-loops.stderr
@@ -27,5 +27,5 @@ LL |         v.push(|| *x = String::new());
 
 error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0382, E0499.
+Some errors have detailed explanations: E0382, E0499, E0524.
 For more information about an error, try `rustc --explain E0382`.