From 27477755edcf76c7bd579661fc83d6ae2a4970eb Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Thu, 30 Aug 2018 02:05:40 +0900
Subject: [PATCH 01/48] [ci] add qemu-system-arm in docker image

---
 src/ci/docker/dist-various-1/Dockerfile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/ci/docker/dist-various-1/Dockerfile b/src/ci/docker/dist-various-1/Dockerfile
index e2484b7224b26..c7e6af28f9d4f 100644
--- a/src/ci/docker/dist-various-1/Dockerfile
+++ b/src/ci/docker/dist-various-1/Dockerfile
@@ -22,7 +22,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
   libssl-dev \
   pkg-config \
   gcc-arm-none-eabi \
-  libnewlib-arm-none-eabi
+  libnewlib-arm-none-eabi \
+  qemu-system-arm
 
 WORKDIR /build
 

From 502023a9baeb9c0f8cc50874e74b22c526fce923 Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Mon, 3 Sep 2018 05:42:40 +0900
Subject: [PATCH 02/48] [ci] thumbv7m-none-eabi: build lm3s6965evb and runon
 QEMU

---
 src/test/run-make/thumb-none-qemu/Makefile | 40 ++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 src/test/run-make/thumb-none-qemu/Makefile

diff --git a/src/test/run-make/thumb-none-qemu/Makefile b/src/test/run-make/thumb-none-qemu/Makefile
new file mode 100644
index 0000000000000..8194b949dfcdc
--- /dev/null
+++ b/src/test/run-make/thumb-none-qemu/Makefile
@@ -0,0 +1,40 @@
+-include ../../run-make-fulldeps/tools.mk
+
+# How to run this
+# $ ./x.py clean
+# $ ./x.py test --target thumbv7m-none-eabi src/test/run-make
+
+ifeq ($(TARGET),thumbv7m-none-eabi))
+
+# For cargo setting
+RUSTC := $(RUSTC_ORIGINAL)
+LD_LIBRARY_PATH := $(HOST_RPATH_DIR)
+# We need to be outside of 'src' dir in order to run cargo
+WORK_DIR := $(TMPDIR)
+
+HERE := $(shell pwd)
+
+CRATE := lm3s6965evb
+CRATE_URL := https://github.com/japaric/lm3s6965evb
+CRATE_SHA1 := 9eeea58826438e84d89e9691a1bb0f85b03d377c
+QEMU_CPU := cortex-m3
+QEMU_MACHINE := lm3s6965evb
+
+all:
+	env
+	mkdir -p $(WORK_DIR)
+	-cd $(WORK_DIR) && rm -rf $(CRATE)
+	cd $(WORK_DIR) && bash -x $(HERE)/../git_clone_sha1.sh $(CRATE) $(CRATE_URL) $(CRATE_SHA1)
+	cd $(WORK_DIR)/$(CRATE) && $(CARGO) build --target $(TARGET) -v 
+	cd $(WORK_DIR)/$(CRATE) && qemu-system-arm \
+       	-cpu $(QEMU_CPU) \
+       	-machine $(QEMU_MACHINE) \
+       	-semihosting-config enable=on,target=native \
+       	-nographic \
+       	-kernel target/$(TARGET)/debug/$(CRATE) > out.txt
+	cd $(WORK_DIR)/$(CRATE) && grep "x = 42" out.txt	
+else
+
+all:
+
+endif

From 719a592cb08ab32d8e348796afd278a36c396c37 Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Mon, 3 Sep 2018 09:51:01 +0900
Subject: [PATCH 03/48] [ci] thumbv7m-none-eabi: add more variable.

---
 src/test/run-make/thumb-none-qemu/Makefile | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/test/run-make/thumb-none-qemu/Makefile b/src/test/run-make/thumb-none-qemu/Makefile
index 8194b949dfcdc..514c8348f82f1 100644
--- a/src/test/run-make/thumb-none-qemu/Makefile
+++ b/src/test/run-make/thumb-none-qemu/Makefile
@@ -11,14 +11,16 @@ RUSTC := $(RUSTC_ORIGINAL)
 LD_LIBRARY_PATH := $(HOST_RPATH_DIR)
 # We need to be outside of 'src' dir in order to run cargo
 WORK_DIR := $(TMPDIR)
-
 HERE := $(shell pwd)
 
+
+# hint: we could set variables per $(TARGET) basis in order to support other targets.
 CRATE := lm3s6965evb
 CRATE_URL := https://github.com/japaric/lm3s6965evb
 CRATE_SHA1 := 9eeea58826438e84d89e9691a1bb0f85b03d377c
 QEMU_CPU := cortex-m3
 QEMU_MACHINE := lm3s6965evb
+QEMU_OUTPUT_TEXT := "x = 42"
 
 all:
 	env
@@ -32,7 +34,7 @@ all:
        	-semihosting-config enable=on,target=native \
        	-nographic \
        	-kernel target/$(TARGET)/debug/$(CRATE) > out.txt
-	cd $(WORK_DIR)/$(CRATE) && grep "x = 42" out.txt	
+	cd $(WORK_DIR)/$(CRATE) && grep $(QEMU_OUTPUT_TEXT) out.txt	
 else
 
 all:

From a04754fd365398e5445d2c4b985023350fb2c4aa Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Sun, 30 Sep 2018 09:34:51 +0900
Subject: [PATCH 04/48] [ci] run-make/thumb-none-qemu: uses cortex-m-rt crate.

---
 src/test/run-make/thumb-none-qemu/Makefile | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/src/test/run-make/thumb-none-qemu/Makefile b/src/test/run-make/thumb-none-qemu/Makefile
index 514c8348f82f1..d1482a1dda49f 100644
--- a/src/test/run-make/thumb-none-qemu/Makefile
+++ b/src/test/run-make/thumb-none-qemu/Makefile
@@ -15,26 +15,17 @@ HERE := $(shell pwd)
 
 
 # hint: we could set variables per $(TARGET) basis in order to support other targets.
-CRATE := lm3s6965evb
-CRATE_URL := https://github.com/japaric/lm3s6965evb
-CRATE_SHA1 := 9eeea58826438e84d89e9691a1bb0f85b03d377c
-QEMU_CPU := cortex-m3
-QEMU_MACHINE := lm3s6965evb
-QEMU_OUTPUT_TEXT := "x = 42"
+CRATE := cortex-m-rt
+CRATE_URL := https://github.com/rust-embedded/cortex-m-rt
+CRATE_SHA1 := 62972c8a89ff54b76f9ef0d600c1fcf7a233aabd
 
 all:
 	env
 	mkdir -p $(WORK_DIR)
 	-cd $(WORK_DIR) && rm -rf $(CRATE)
 	cd $(WORK_DIR) && bash -x $(HERE)/../git_clone_sha1.sh $(CRATE) $(CRATE_URL) $(CRATE_SHA1)
-	cd $(WORK_DIR)/$(CRATE) && $(CARGO) build --target $(TARGET) -v 
-	cd $(WORK_DIR)/$(CRATE) && qemu-system-arm \
-       	-cpu $(QEMU_CPU) \
-       	-machine $(QEMU_MACHINE) \
-       	-semihosting-config enable=on,target=native \
-       	-nographic \
-       	-kernel target/$(TARGET)/debug/$(CRATE) > out.txt
-	cd $(WORK_DIR)/$(CRATE) && grep $(QEMU_OUTPUT_TEXT) out.txt	
+	cd $(WORK_DIR)/$(CRATE) && $(CARGO) run --target $(TARGET) --example qemu           | grep "x = 42"
+	cd $(WORK_DIR)/$(CRATE) && $(CARGO) run --target $(TARGET) --example qemu --release | grep "x = 42"
 else
 
 all:

From fdf4d6efac79de2df444ee4975b381b43d76dee1 Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Sun, 30 Sep 2018 10:55:49 +0900
Subject: [PATCH 05/48] [ci] run-make/thumb-none-qemu: add thumbv6m-none-qemu

---
 src/test/run-make/thumb-none-qemu/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/run-make/thumb-none-qemu/Makefile b/src/test/run-make/thumb-none-qemu/Makefile
index d1482a1dda49f..518b2ec643175 100644
--- a/src/test/run-make/thumb-none-qemu/Makefile
+++ b/src/test/run-make/thumb-none-qemu/Makefile
@@ -4,7 +4,7 @@
 # $ ./x.py clean
 # $ ./x.py test --target thumbv7m-none-eabi src/test/run-make
 
-ifeq ($(TARGET),thumbv7m-none-eabi))
+ifneq (,$(filter $(TARGET),thumbv6m-none-eabi thumbv7m-none-eabi))
 
 # For cargo setting
 RUSTC := $(RUSTC_ORIGINAL)

From 8b097c4ce92869b012c36ba0c7c0a2a096a17849 Mon Sep 17 00:00:00 2001
From: Oliver Schneider <github35764891676564198441@oli-obk.de>
Date: Thu, 4 Oct 2018 16:23:22 +0200
Subject: [PATCH 06/48] Don't try to promote already promoted out temporaries

---
 src/librustc_mir/transform/promote_consts.rs   |  2 ++
 src/librustc_mir/transform/qualify_consts.rs   | 18 ++++++++++++++----
 .../ui/consts/const-eval/double_promotion.rs   | 17 +++++++++++++++++
 3 files changed, 33 insertions(+), 4 deletions(-)
 create mode 100644 src/test/ui/consts/const-eval/double_promotion.rs

diff --git a/src/librustc_mir/transform/promote_consts.rs b/src/librustc_mir/transform/promote_consts.rs
index 34339b0634194..bba9260f2b829 100644
--- a/src/librustc_mir/transform/promote_consts.rs
+++ b/src/librustc_mir/transform/promote_consts.rs
@@ -332,6 +332,8 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                             let operand = Operand::Copy(promoted_place(ty, span));
                             mem::replace(&mut args[index], operand)
                         }
+                        // already promoted out
+                        TerminatorKind::Goto { .. } => return,
                         _ => bug!()
                     }
                 }
diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index 17fe78d325cf1..4808f02c1dff4 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -812,7 +812,9 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
 
             let fn_ty = func.ty(self.mir, self.tcx);
             let mut callee_def_id = None;
-            let (mut is_shuffle, mut is_const_fn) = (false, false);
+            let mut is_shuffle = false;
+            let mut is_const_fn = false;
+            let mut is_promotable_const_fn = false;
             if let ty::FnDef(def_id, _) = fn_ty.sty {
                 callee_def_id = Some(def_id);
                 match self.tcx.fn_sig(def_id).abi() {
@@ -873,6 +875,9 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                             // functions without #[rustc_promotable]
                             if self.tcx.is_promotable_const_fn(def_id) {
                                 is_const_fn = true;
+                                is_promotable_const_fn = true;
+                            } else if self.tcx.is_const_fn(def_id) {
+                                is_const_fn = true;
                             }
                         } else {
                             // stable const fn or unstable const fns with their feature gate
@@ -974,7 +979,9 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                     if !constant_arguments.contains(&i) {
                         return
                     }
-                    if this.qualif.is_empty() {
+                    // if the argument requires a constant, we care about constness, not
+                    // promotability
+                    if (this.qualif - Qualif::NOT_PROMOTABLE).is_empty() {
                         this.promotion_candidates.push(candidate);
                     } else {
                         this.tcx.sess.span_err(this.span,
@@ -985,7 +992,11 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
             }
 
             // non-const fn calls.
-            if !is_const_fn {
+            if is_const_fn {
+                if !is_promotable_const_fn && self.mode == Mode::Fn {
+                    self.qualif = Qualif::NOT_PROMOTABLE;
+                }
+            } else {
                 self.qualif = Qualif::NOT_CONST;
                 if self.mode != Mode::Fn {
                     self.tcx.sess.delay_span_bug(
@@ -1003,7 +1014,6 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                     // Be conservative about the returned value of a const fn.
                     let tcx = self.tcx;
                     let ty = dest.ty(self.mir, tcx).to_ty(tcx);
-                    self.qualif = Qualif::empty();
                     self.add_type(ty);
                 }
                 self.assign(dest, location);
diff --git a/src/test/ui/consts/const-eval/double_promotion.rs b/src/test/ui/consts/const-eval/double_promotion.rs
new file mode 100644
index 0000000000000..0e75ea8e66b3c
--- /dev/null
+++ b/src/test/ui/consts/const-eval/double_promotion.rs
@@ -0,0 +1,17 @@
+// compile-pass
+
+#![feature(const_fn, rustc_attrs)]
+
+#[rustc_args_required_const(0)]
+pub const fn a(value: u8) -> u8 {
+    value
+}
+
+#[rustc_args_required_const(0)]
+pub fn b(_: u8) {
+    unimplemented!()
+}
+
+fn main() {
+    let _ = b(a(0));
+}

From 7d3d835c58e789127744076c97110664ea9c6087 Mon Sep 17 00:00:00 2001
From: Philip Munksgaard <pmunksgaard@gmail.com>
Date: Thu, 4 Oct 2018 22:17:01 +0200
Subject: [PATCH 07/48] replace escape-rust-expr test with
 dont-show-const-contents

The old test was supposed to check for proper html escaping when showing the
contents of constants. This was changed as part of #53409. The revised test
asserts that the contents of the constant is not shown as part of the generated
documentation.
---
 .../{escape-rust-expr.rs => dont-show-const-contents.rs}  | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
 rename src/test/rustdoc/{escape-rust-expr.rs => dont-show-const-contents.rs} (64%)

diff --git a/src/test/rustdoc/escape-rust-expr.rs b/src/test/rustdoc/dont-show-const-contents.rs
similarity index 64%
rename from src/test/rustdoc/escape-rust-expr.rs
rename to src/test/rustdoc/dont-show-const-contents.rs
index 4594eb95ea18e..1392c62b4abb1 100644
--- a/src/test/rustdoc/escape-rust-expr.rs
+++ b/src/test/rustdoc/dont-show-const-contents.rs
@@ -8,8 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// Test that we HTML-escape Rust expressions, where HTML special chars
-// can occur, and we know it's definitely not markup.
+// Test that the contents of constants are not displayed as part of the
+// documentation.
 
-// @!has escape_rust_expr/constant.CONST_S.html '//pre[@class="rust const"]' '"<script>"'
-pub const CONST_S: &'static str = "<script>";
+// @!has dont_show_const_contents/constant.CONST_S.html 'dont show this'
+pub const CONST_S: &'static str = "dont show this";

From f97e094b198a0eb6115251f42e3f6e5dcec731f8 Mon Sep 17 00:00:00 2001
From: Philip Munksgaard <pmunksgaard@gmail.com>
Date: Thu, 4 Oct 2018 22:23:19 +0200
Subject: [PATCH 08/48] Add compile flags to playground-empty test

"Run" links to the playground are not added to the generated documentation if
the unstable `--playground-url` argument is not passed to rustdoc. Therefore,
without specifying `--playground-url` as a compile-flag, the test doesn't
correctly assert that `#![doc(html_playground_url = "")]` removes playground
links.
---
 src/test/rustdoc/playground-empty.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/test/rustdoc/playground-empty.rs b/src/test/rustdoc/playground-empty.rs
index 00881a62dd0a8..2b3120fa5b4a1 100644
--- a/src/test/rustdoc/playground-empty.rs
+++ b/src/test/rustdoc/playground-empty.rs
@@ -12,6 +12,8 @@
 
 #![doc(html_playground_url = "")]
 
+// compile-flags:-Z unstable-options --playground-url https://play.rust-lang.org/
+
 //! module docs
 //!
 //! ```

From 46ccce0803386db3d7c0dbdd30d31474889b64a0 Mon Sep 17 00:00:00 2001
From: Philip Munksgaard <pmunksgaard@gmail.com>
Date: Fri, 5 Oct 2018 18:24:25 +0200
Subject: [PATCH 09/48] Remove duplicate test line

---
 src/test/rustdoc/manual_impl.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/test/rustdoc/manual_impl.rs b/src/test/rustdoc/manual_impl.rs
index 54a8a76483341..db48a6525230c 100644
--- a/src/test/rustdoc/manual_impl.rs
+++ b/src/test/rustdoc/manual_impl.rs
@@ -35,7 +35,6 @@ pub trait T {
 // @has  - '//*[@class="docblock"]' 'Docs associated with the S1 trait a_method implementation.'
 // @!has - '//*[@class="docblock"]' 'Docs associated with the trait a_method definition.'
 // @has - '//*[@class="docblock"]' 'Docs associated with the trait b_method definition.'
-// @has - '//*[@class="docblock"]' 'Docs associated with the trait b_method definition.'
 // @has - '//*[@class="docblock"]' 'Docs associated with the trait c_method definition.'
 // @!has - '//*[@class="docblock"]' 'There is another line'
 // @has - '//*[@class="docblock"]' 'Read more'

From 5f8dc0ddf47274e0a98111edc816b825484d0d1a Mon Sep 17 00:00:00 2001
From: Philip Munksgaard <pmunksgaard@gmail.com>
Date: Fri, 5 Oct 2018 19:08:52 +0200
Subject: [PATCH 10/48] Fix unneeded-trait-implementations-title test

The `@!has` command does not support specifying just a PATH and an XPATH. That
means that the previous test searched for the literal string
`//h2[@id="implementations"]` within the generated output, which obviously
didn't exist. Even after adding a trait implementation, the test still passed.
The correct way to check for the existence of a DOM element with the id
`implementations` is to use the `@count` keyword.
---
 src/test/rustdoc/unneeded-trait-implementations-title.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/rustdoc/unneeded-trait-implementations-title.rs b/src/test/rustdoc/unneeded-trait-implementations-title.rs
index 2c074179e32b5..c87b533b9d474 100644
--- a/src/test/rustdoc/unneeded-trait-implementations-title.rs
+++ b/src/test/rustdoc/unneeded-trait-implementations-title.rs
@@ -12,4 +12,4 @@
 
 pub struct Bar;
 
-// @!has foo/struct.Bar.html '//*[@id="implementations"]'
+// @count foo/struct.Bar.html '//*[@id="implementations"]' 0

From a9a26de8b3b8a0acda3b7716f6e9b4b1bfb799dd Mon Sep 17 00:00:00 2001
From: Philip Munksgaard <pmunksgaard@gmail.com>
Date: Fri, 5 Oct 2018 22:55:13 +0200
Subject: [PATCH 11/48] Fix redirect.rs test

Struct names are no longer encapsulated in `<code>` tags, which meant that the
test was not correctly verifying that it wasn't being show. I've also added a
check to make sure the documentation page for the redirect::Qux struct is not
generated at all.
---
 src/test/rustdoc/redirect.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/test/rustdoc/redirect.rs b/src/test/rustdoc/redirect.rs
index 98e66e8c024bd..c20dd815d8ce7 100644
--- a/src/test/rustdoc/redirect.rs
+++ b/src/test/rustdoc/redirect.rs
@@ -43,6 +43,7 @@ mod private_no_inline {
 
 // @has redirect/index.html
 // @has - '//code' 'pub use private_no_inline::Qux'
-// @!has - '//code/a' 'Qux'
+// @!has - '//a' 'Qux'
+// @!has redirect/struct.Qux.html
 #[doc(no_inline)]
 pub use private_no_inline::Qux;

From 28596ade7169abd483410b22a4bd8703c4ccc8f7 Mon Sep 17 00:00:00 2001
From: Philip Munksgaard <pmunksgaard@gmail.com>
Date: Fri, 5 Oct 2018 23:28:08 +0200
Subject: [PATCH 12/48] Fix empty-section.rs test

The Auto Trait Implementation section is not wrapped in a
`synthetic-implementations` class. In fact, it is wrapped in a
`synthetic-implementations` id. However, we can generalize and completely remove
the `synthetic-implementations` requirement. We just have to verify that there's
no mention of "Auto Trait Implementations" anywhere.
---
 src/test/rustdoc/empty-section.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/rustdoc/empty-section.rs b/src/test/rustdoc/empty-section.rs
index 3748313593fc2..11a027a13f7e3 100644
--- a/src/test/rustdoc/empty-section.rs
+++ b/src/test/rustdoc/empty-section.rs
@@ -15,6 +15,6 @@
 pub struct Foo;
 
 // @has foo/struct.Foo.html
-// @!has - '//*[@class="synthetic-implementations"]' 'Auto Trait Implementations'
+// @!has - 'Auto Trait Implementations'
 impl !Send for Foo {}
 impl !Sync for Foo {}

From e961d397cab900c55f8d8c104648852e2b63664e Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Mon, 8 Oct 2018 22:51:37 +0200
Subject: [PATCH 13/48] Add line numbers option to rustdoc

---
 src/librustdoc/html/highlight.rs            | 13 ++++---
 src/librustdoc/html/render.rs               |  1 +
 src/librustdoc/html/static/main.js          | 42 ++++++++++++++++-----
 src/librustdoc/html/static/rustdoc.css      | 18 +++++++++
 src/librustdoc/html/static/themes/dark.css  |  4 ++
 src/librustdoc/html/static/themes/light.css |  4 ++
 6 files changed, 68 insertions(+), 14 deletions(-)

diff --git a/src/librustdoc/html/highlight.rs b/src/librustdoc/html/highlight.rs
index 5df4862290e3c..bd4cfe51ea72f 100644
--- a/src/librustdoc/html/highlight.rs
+++ b/src/librustdoc/html/highlight.rs
@@ -28,9 +28,12 @@ use syntax::parse;
 use syntax_pos::{Span, FileName};
 
 /// Highlights `src`, returning the HTML output.
-pub fn render_with_highlighting(src: &str, class: Option<&str>,
-                                extension: Option<&str>,
-                                tooltip: Option<(&str, &str)>) -> String {
+pub fn render_with_highlighting(
+    src: &str,
+    class: Option<&str>,
+    extension: Option<&str>,
+    tooltip: Option<(&str, &str)>,
+) -> String {
     debug!("highlighting: ================\n{}\n==============", src);
     let sess = parse::ParseSess::new(FilePathMapping::empty());
     let fm = sess.source_map().new_source_file(FileName::Custom("stdin".to_string()),
@@ -373,9 +376,9 @@ impl Class {
 }
 
 fn write_header(class: Option<&str>, out: &mut dyn Write) -> io::Result<()> {
-    write!(out, "<pre class=\"rust {}\">\n", class.unwrap_or(""))
+    write!(out, "<div class=\"example-wrap\"><pre class=\"rust {}\">\n", class.unwrap_or(""))
 }
 
 fn write_footer(out: &mut dyn Write) -> io::Result<()> {
-    write!(out, "</pre>\n")
+    write!(out, "</pre></div>\n")
 }
diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index 1c61e73fae03c..c83c5d382ddcc 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -1709,6 +1709,7 @@ impl<'a> Settings<'a> {
                 ("method-docs", "Auto-hide item methods' documentation", false),
                 ("go-to-only-result", "Directly go to item in search if there is only one result",
                  false),
+                ("line-numbers", "Show line numbers on code examples", false),
             ],
             root_path,
             suffix,
diff --git a/src/librustdoc/html/static/main.js b/src/librustdoc/html/static/main.js
index 6307dda454da8..9d1a5c3837830 100644
--- a/src/librustdoc/html/static/main.js
+++ b/src/librustdoc/html/static/main.js
@@ -2093,6 +2093,7 @@
         return wrapper;
     }
 
+    var hideItemDeclarations = getCurrentValue('rustdoc-item-declarations') === "false";
     onEach(document.getElementsByClassName('docblock'), function(e) {
         if (hasClass(e, 'autohide')) {
             var wrap = e.previousElementSibling;
@@ -2116,16 +2117,14 @@
             }
         }
         if (e.parentNode.id === "main") {
-            var otherMessage;
+            var otherMessage = '';
             var fontSize;
             var extraClass;
-            var show = true;
 
             if (hasClass(e, "type-decl")) {
                 fontSize = "20px";
                 otherMessage = '&nbsp;Show&nbsp;declaration';
-                show = getCurrentValue('rustdoc-item-declarations') === "false";
-                if (!show) {
+                if (hideItemDeclarations === false) {
                     extraClass = 'collapsed';
                 }
             } else if (hasClass(e, "non-exhaustive")) {
@@ -2142,8 +2141,12 @@
                 extraClass = "marg-left";
             }
 
-            e.parentNode.insertBefore(createToggle(otherMessage, fontSize, extraClass, show), e);
-            if (otherMessage && show) {
+            e.parentNode.insertBefore(createToggle(otherMessage,
+                                                   fontSize,
+                                                   extraClass,
+                                                   hideItemDeclarations),
+                                      e);
+            if (otherMessage.length > 0 && hideItemDeclarations === true) {
                 collapseDocs(e.previousSibling.childNodes[0], "toggle");
             }
         }
@@ -2186,13 +2189,33 @@
         });
     }
 
+    // To avoid checking on "rustdoc-item-attributes" value on every loop...
+    var itemAttributesFunc = function() {};
+    if (getCurrentValue("rustdoc-item-attributes") !== "false") {
+        itemAttributesFunc = function(x) {
+            collapseDocs(x.previousSibling.childNodes[0], "toggle");
+        };
+    }
     onEach(document.getElementById('main').getElementsByClassName('attributes'), function(i_e) {
         i_e.parentNode.insertBefore(createToggleWrapper(toggle.cloneNode(true)), i_e);
-        if (getCurrentValue("rustdoc-item-attributes") !== "false") {
-            collapseDocs(i_e.previousSibling.childNodes[0], "toggle");
-        }
+        itemAttributesFunc(i_e);
     });
 
+    // To avoid checking on "rustdoc-line-numbers" value on every loop...
+    var lineNumbersFunc = function() {};
+    if (getCurrentValue("rustdoc-line-numbers") === "true") {
+        lineNumbersFunc = function(x) {
+            var count = x.textContent.split('\n').length;
+            var elems = [];
+            for (var i = 0; i < count; ++i) {
+                elems.push(i + 1);
+            }
+            var node = document.createElement('pre');
+            addClass(node, 'line-number');
+            node.innerHTML = elems.join('\n');
+            x.parentNode.insertBefore(node, x);
+        };
+    }
     onEach(document.getElementsByClassName('rust-example-rendered'), function(e) {
         if (hasClass(e, 'compile_fail')) {
             e.addEventListener("mouseover", function(event) {
@@ -2209,6 +2232,7 @@
                 e.previousElementSibling.childNodes[0].style.color = '';
             });
         }
+        lineNumbersFunc(e);
     });
 
     function showModal(content) {
diff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index ee811f3379239..5817a22574953 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -283,6 +283,24 @@ nav.sub {
 	padding-left: 0;
 }
 
+.example-wrap {
+	display: inline-flex;
+	width: 100%;
+}
+
+.example-wrap > pre.line-number {
+	overflow: initial;
+	border: 1px solid;
+	border-top-left-radius: 5px;
+	border-bottom-left-radius: 5px;
+	padding: 13px 8px;
+	text-align: right;
+}
+
+.example-wrap > pre.rust {
+	width: 100%;
+}
+
 #search {
 	margin-left: 230px;
 	position: relative;
diff --git a/src/librustdoc/html/static/themes/dark.css b/src/librustdoc/html/static/themes/dark.css
index 34a1d71beecfc..e179c4586bc74 100644
--- a/src/librustdoc/html/static/themes/dark.css
+++ b/src/librustdoc/html/static/themes/dark.css
@@ -233,6 +233,10 @@ pre.rust .question-mark {
 	color: #ff9011;
 }
 
+.example-wrap > pre.line-number {
+	border-color: #4a4949;
+}
+
 a.test-arrow {
 	background-color: rgba(78, 139, 202, 0.2);
 }
diff --git a/src/librustdoc/html/static/themes/light.css b/src/librustdoc/html/static/themes/light.css
index 8218b1b371ea7..6ef9875ea2d4d 100644
--- a/src/librustdoc/html/static/themes/light.css
+++ b/src/librustdoc/html/static/themes/light.css
@@ -227,6 +227,10 @@ pre.rust .question-mark {
 	color: #ff9011;
 }
 
+.example-wrap > pre.line-number {
+	border-color: #c7c7c7;
+}
+
 a.test-arrow {
 	background-color: rgba(78, 139, 202, 0.2);
 }

From 5b0f4869764167c2444d179ace2e220943506a7b Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Wed, 10 Oct 2018 10:50:25 +0900
Subject: [PATCH 14/48] [ci] run-make/thumb-none-qemu:  transfer logic to
 script.sh

---
 src/test/run-make/thumb-none-qemu/Makefile  | 21 +++++++--------------
 src/test/run-make/thumb-none-qemu/script.sh | 16 ++++++++++++++++
 2 files changed, 23 insertions(+), 14 deletions(-)
 create mode 100644 src/test/run-make/thumb-none-qemu/script.sh

diff --git a/src/test/run-make/thumb-none-qemu/Makefile b/src/test/run-make/thumb-none-qemu/Makefile
index 518b2ec643175..91921a2a9f86d 100644
--- a/src/test/run-make/thumb-none-qemu/Makefile
+++ b/src/test/run-make/thumb-none-qemu/Makefile
@@ -7,27 +7,20 @@
 ifneq (,$(filter $(TARGET),thumbv6m-none-eabi thumbv7m-none-eabi))
 
 # For cargo setting
-RUSTC := $(RUSTC_ORIGINAL)
+export RUSTC := $(RUSTC_ORIGINAL)
 LD_LIBRARY_PATH := $(HOST_RPATH_DIR)
 # We need to be outside of 'src' dir in order to run cargo
-WORK_DIR := $(TMPDIR)
-HERE := $(shell pwd)
+export WORK_DIR := $(TMPDIR)
+export HERE := $(shell pwd)
 
 
 # hint: we could set variables per $(TARGET) basis in order to support other targets.
-CRATE := cortex-m-rt
-CRATE_URL := https://github.com/rust-embedded/cortex-m-rt
-CRATE_SHA1 := 62972c8a89ff54b76f9ef0d600c1fcf7a233aabd
+export CRATE := cortex-m-rt
+export CRATE_URL := https://github.com/rust-embedded/cortex-m-rt
+export CRATE_SHA1 := 62972c8a89ff54b76f9ef0d600c1fcf7a233aabd
 
 all:
-	env
-	mkdir -p $(WORK_DIR)
-	-cd $(WORK_DIR) && rm -rf $(CRATE)
-	cd $(WORK_DIR) && bash -x $(HERE)/../git_clone_sha1.sh $(CRATE) $(CRATE_URL) $(CRATE_SHA1)
-	cd $(WORK_DIR)/$(CRATE) && $(CARGO) run --target $(TARGET) --example qemu           | grep "x = 42"
-	cd $(WORK_DIR)/$(CRATE) && $(CARGO) run --target $(TARGET) --example qemu --release | grep "x = 42"
+	bash script.sh
 else
-
 all:
-
 endif
diff --git a/src/test/run-make/thumb-none-qemu/script.sh b/src/test/run-make/thumb-none-qemu/script.sh
new file mode 100644
index 0000000000000..022f1cef63191
--- /dev/null
+++ b/src/test/run-make/thumb-none-qemu/script.sh
@@ -0,0 +1,16 @@
+set -exuo pipefail
+
+CRATE=cortex-m-rt
+CRATE_URL=https://github.com/rust-embedded/cortex-m-rt
+CRATE_SHA1=62972c8a89ff54b76f9ef0d600c1fcf7a233aabd
+
+env | sort
+mkdir -p $WORK_DIR
+pushd $WORK_DIR
+    rm -rf $CRATE || echo OK
+    bash -x $HERE/../git_clone_sha1.sh $CRATE $CRATE_URL $CRATE_SHA1
+    pushd $CRATE
+        $CARGO run --target $TARGET --example qemu           | grep "x = 42"
+        $CARGO run --target $TARGET --example qemu --release | grep "x = 42"
+    popd
+popd
\ No newline at end of file

From a4faa5ef7319ea6b457fee233a0699569c393f7a Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Wed, 10 Oct 2018 10:51:28 +0900
Subject: [PATCH 15/48] [ci] run-make/thumb-none-qemu:  transfer logic to
 script.sh (2)

---
 src/test/run-make/thumb-none-qemu/Makefile | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/src/test/run-make/thumb-none-qemu/Makefile b/src/test/run-make/thumb-none-qemu/Makefile
index 91921a2a9f86d..bf57bc5b31105 100644
--- a/src/test/run-make/thumb-none-qemu/Makefile
+++ b/src/test/run-make/thumb-none-qemu/Makefile
@@ -13,12 +13,6 @@ LD_LIBRARY_PATH := $(HOST_RPATH_DIR)
 export WORK_DIR := $(TMPDIR)
 export HERE := $(shell pwd)
 
-
-# hint: we could set variables per $(TARGET) basis in order to support other targets.
-export CRATE := cortex-m-rt
-export CRATE_URL := https://github.com/rust-embedded/cortex-m-rt
-export CRATE_SHA1 := 62972c8a89ff54b76f9ef0d600c1fcf7a233aabd
-
 all:
 	bash script.sh
 else

From e8bc04e1c8e0e27bcc3e5915d465ca12b0254565 Mon Sep 17 00:00:00 2001
From: Philip Munksgaard <pmunksgaard@gmail.com>
Date: Wed, 10 Oct 2018 21:04:52 +0200
Subject: [PATCH 16/48] Use XPATH notation to match against flattened nodes

The generated code would look like `<code>impl <a href="...">Foo</a></code>`
which the plain text matcher doesn't match. But by using the XPATH notation, the
nodes are flattened and we can correctly assert that `impl Foo` does not occur
in the generated docs.
---
 src/test/rustdoc/hidden-methods.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/test/rustdoc/hidden-methods.rs b/src/test/rustdoc/hidden-methods.rs
index 18f5f086cd1a4..aea5f44e2a723 100644
--- a/src/test/rustdoc/hidden-methods.rs
+++ b/src/test/rustdoc/hidden-methods.rs
@@ -28,12 +28,12 @@ pub mod hidden {
 
 // @has foo/struct.Foo.html
 // @!has - 'Methods'
-// @!has - 'impl Foo'
+// @!has - '//code' 'impl Foo'
 // @!has - 'this_should_be_hidden'
 pub use hidden::Foo;
 
 // @has foo/struct.Bar.html
 // @!has - 'Methods'
-// @!has - 'impl Bar'
+// @!has - '//code' 'impl Bar'
 // @!has - 'this_should_be_hidden'
 pub use hidden::Bar;

From 9dbe902800d5ba87b08b15adb157adbe9be02e75 Mon Sep 17 00:00:00 2001
From: Philip Munksgaard <pmunksgaard@gmail.com>
Date: Wed, 10 Oct 2018 21:18:08 +0200
Subject: [PATCH 17/48] Fix issue-46767 test

The link that is matched against is not the same as would be generated by
rustdoc. We should also check that the `foo/private` directory is not generated
at all.
---
 src/test/rustdoc/issue-46767.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/test/rustdoc/issue-46767.rs b/src/test/rustdoc/issue-46767.rs
index 855de150b0a37..1e6b697cd5fd9 100644
--- a/src/test/rustdoc/issue-46767.rs
+++ b/src/test/rustdoc/issue-46767.rs
@@ -15,4 +15,5 @@ mod private {
 }
 pub use self::private::Enum::*;
 
-// @!has foo/index.html '//a/@href' './private/index.html'
+// @!has-dir foo/private
+// @!has foo/index.html '//a/@href' 'private/index.html'

From df79da96614467e97a8f8ddd58106b456e44dee1 Mon Sep 17 00:00:00 2001
From: Philip Munksgaard <pmunksgaard@gmail.com>
Date: Wed, 10 Oct 2018 22:01:05 +0200
Subject: [PATCH 18/48] Fix typo in deprecated_impls

The function is called `fn_def_with_doc`, not `fn_def_with`.
---
 src/test/rustdoc/deprecated-impls.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/rustdoc/deprecated-impls.rs b/src/test/rustdoc/deprecated-impls.rs
index bcf0645766b30..3fb83bff91604 100644
--- a/src/test/rustdoc/deprecated-impls.rs
+++ b/src/test/rustdoc/deprecated-impls.rs
@@ -109,7 +109,7 @@ impl Bar for Foo2 {
 
     // @has - '//*[@class="stab deprecated"]' 'Deprecated since 1.0.5: fn_def_with_doc'
     // @has - 'fn_def_with_doc short'
-    // @!has - 'fn_def_with full'
+    // @!has - 'fn_def_with_doc full'
     fn fn_def_with_doc() {}
 
     // @has - '//*[@class="stab deprecated"]' 'Deprecated since 1.0.6: fn_def_without_doc'

From a9217e316c7fd35ef5be4b0c1e84f637ec0fa813 Mon Sep 17 00:00:00 2001
From: Philip Munksgaard <pmunksgaard@gmail.com>
Date: Wed, 10 Oct 2018 22:30:15 +0200
Subject: [PATCH 19/48] Fix typo in issue-13698.rs

---
 src/test/rustdoc/issue-13698.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/rustdoc/issue-13698.rs b/src/test/rustdoc/issue-13698.rs
index cf9b30a0fe987..b0efee511bc7d 100644
--- a/src/test/rustdoc/issue-13698.rs
+++ b/src/test/rustdoc/issue-13698.rs
@@ -22,5 +22,5 @@ pub trait Bar {
     fn bar(&self) {}
 }
 
-// @!has issue_13698/struct.Foo.html '//*[@id="method.foo"]' 'fn bar'
+// @!has issue_13698/struct.Foo.html '//*[@id="method.bar"]' 'fn bar'
 impl Bar for Foo {}

From 8d2b2ee5c2ea2e7de7bb14aeaae2c6f3b75a0305 Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Tue, 16 Oct 2018 20:56:02 +0900
Subject: [PATCH 20/48] [ci] run-make/thumb-none-qemu: add example crate.

---
 src/test/run-make/thumb-none-qemu/Makefile    | 12 +++++++-
 .../thumb-none-qemu/example/Cargo.toml        | 11 +++++++
 .../run-make/thumb-none-qemu/example/memory.x | 23 ++++++++++++++
 .../thumb-none-qemu/example/src/main.rs       | 30 +++++++++++++++++++
 src/test/run-make/thumb-none-qemu/script.sh   | 11 +++----
 5 files changed, 79 insertions(+), 8 deletions(-)
 create mode 100644 src/test/run-make/thumb-none-qemu/example/Cargo.toml
 create mode 100644 src/test/run-make/thumb-none-qemu/example/memory.x
 create mode 100644 src/test/run-make/thumb-none-qemu/example/src/main.rs

diff --git a/src/test/run-make/thumb-none-qemu/Makefile b/src/test/run-make/thumb-none-qemu/Makefile
index bf57bc5b31105..75c17372bc238 100644
--- a/src/test/run-make/thumb-none-qemu/Makefile
+++ b/src/test/run-make/thumb-none-qemu/Makefile
@@ -8,11 +8,21 @@ ifneq (,$(filter $(TARGET),thumbv6m-none-eabi thumbv7m-none-eabi))
 
 # For cargo setting
 export RUSTC := $(RUSTC_ORIGINAL)
-LD_LIBRARY_PATH := $(HOST_RPATH_DIR)
+export LD_LIBRARY_PATH := $(HOST_RPATH_DIR)
 # We need to be outside of 'src' dir in order to run cargo
 export WORK_DIR := $(TMPDIR)
 export HERE := $(shell pwd)
 
+## clean up unused env variables which might cause harm.
+# unexport RUSTC_LINKER
+# unexport RUSTC_BOOTSTRAP
+# unexport RUST_BUILD_STAGE
+# unexport RUST_TEST_THREADS
+# unexport RUST_TEST_TMPDIR
+# unexport AR
+# unexport CC
+# unexport CXX
+
 all:
 	bash script.sh
 else
diff --git a/src/test/run-make/thumb-none-qemu/example/Cargo.toml b/src/test/run-make/thumb-none-qemu/example/Cargo.toml
new file mode 100644
index 0000000000000..499553304c681
--- /dev/null
+++ b/src/test/run-make/thumb-none-qemu/example/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "example"
+version = "0.1.0"
+authors = ["Hideki Sekine <sekineh@me.com>"]
+# edition = "2018"
+
+[dependencies]
+cortex-m = "0.5.4"
+cortex-m-rt = "=0.5.4"
+panic-halt = "0.2.0"
+cortex-m-semihosting = "0.3.1"
diff --git a/src/test/run-make/thumb-none-qemu/example/memory.x b/src/test/run-make/thumb-none-qemu/example/memory.x
new file mode 100644
index 0000000000000..dc7ad967a42a8
--- /dev/null
+++ b/src/test/run-make/thumb-none-qemu/example/memory.x
@@ -0,0 +1,23 @@
+/* Device specific memory layout */
+
+/* This file is used to build the cortex-m-rt examples,
+   but not other applications using cortex-m-rt. */
+
+MEMORY
+{
+  /* FLASH and RAM are mandatory memory regions */
+  /* Update examples/data_overflow.rs if you change these sizes. */
+  FLASH : ORIGIN = 0x00000000, LENGTH = 256K
+  RAM : ORIGIN = 0x20000000, LENGTH = 64K
+
+  /* More memory regions can declared: for example this is a second RAM region */
+  /* CCRAM : ORIGIN = 0x10000000, LENGTH = 8K */
+}
+
+/* The location of the stack can be overridden using the `_stack_start` symbol.
+   By default it will be placed at the end of the RAM region */
+/* _stack_start = ORIGIN(CCRAM) + LENGTH(CCRAM); */
+
+/* The location of the .text section can be overridden using the `_stext` symbol.
+   By default it will place after .vector_table */
+/* _stext = ORIGIN(FLASH) + 0x40c; */
\ No newline at end of file
diff --git a/src/test/run-make/thumb-none-qemu/example/src/main.rs b/src/test/run-make/thumb-none-qemu/example/src/main.rs
new file mode 100644
index 0000000000000..e94aa74de5883
--- /dev/null
+++ b/src/test/run-make/thumb-none-qemu/example/src/main.rs
@@ -0,0 +1,30 @@
+// #![feature(stdsimd)]
+#![no_main]
+#![no_std]
+
+extern crate cortex_m;
+
+extern crate cortex_m_rt as rt;
+extern crate cortex_m_semihosting as semihosting;
+extern crate panic_halt;
+
+use core::fmt::Write;
+use cortex_m::asm;
+use rt::entry;
+
+entry!(main);
+
+fn main() -> ! {
+    let x = 42;
+
+    loop {
+        asm::nop();
+
+        // write something through semihosting interface
+        let mut hstdout = semihosting::hio::hstdout().unwrap();
+        write!(hstdout, "x = {}\n", x);
+
+        // exit from qemu
+        semihosting::debug::exit(semihosting::debug::EXIT_SUCCESS);
+    }
+}
\ No newline at end of file
diff --git a/src/test/run-make/thumb-none-qemu/script.sh b/src/test/run-make/thumb-none-qemu/script.sh
index 022f1cef63191..5c46c4bd26dc0 100644
--- a/src/test/run-make/thumb-none-qemu/script.sh
+++ b/src/test/run-make/thumb-none-qemu/script.sh
@@ -1,16 +1,13 @@
 set -exuo pipefail
 
-CRATE=cortex-m-rt
-CRATE_URL=https://github.com/rust-embedded/cortex-m-rt
-CRATE_SHA1=62972c8a89ff54b76f9ef0d600c1fcf7a233aabd
+CRATE=example
 
 env | sort
 mkdir -p $WORK_DIR
 pushd $WORK_DIR
     rm -rf $CRATE || echo OK
-    bash -x $HERE/../git_clone_sha1.sh $CRATE $CRATE_URL $CRATE_SHA1
+    cp -a $HERE/example .
     pushd $CRATE
-        $CARGO run --target $TARGET --example qemu           | grep "x = 42"
-        $CARGO run --target $TARGET --example qemu --release | grep "x = 42"
+        $CARGO run --target $TARGET
     popd
-popd
\ No newline at end of file
+popd

From f40fd4bace651be6fad51723b139dbebbf00f883 Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Tue, 16 Oct 2018 21:07:44 +0900
Subject: [PATCH 21/48] [ci] run both debug and release

---
 src/test/run-make/thumb-none-qemu/script.sh | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/test/run-make/thumb-none-qemu/script.sh b/src/test/run-make/thumb-none-qemu/script.sh
index 5c46c4bd26dc0..c7133f8fb7fce 100644
--- a/src/test/run-make/thumb-none-qemu/script.sh
+++ b/src/test/run-make/thumb-none-qemu/script.sh
@@ -8,6 +8,7 @@ pushd $WORK_DIR
     rm -rf $CRATE || echo OK
     cp -a $HERE/example .
     pushd $CRATE
-        $CARGO run --target $TARGET
+        $CARGO run --target $TARGET           | grep "x = 42"
+        $CARGO run --target $TARGET --release | grep "x = 42"
     popd
 popd

From 3064e0a16600ab4e32e486a495b1da5b737b711a Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Tue, 16 Oct 2018 21:08:13 +0900
Subject: [PATCH 22/48] [ci] fix tidy warning.

---
 src/test/run-make/thumb-none-qemu/example/src/main.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/run-make/thumb-none-qemu/example/src/main.rs b/src/test/run-make/thumb-none-qemu/example/src/main.rs
index e94aa74de5883..d88a327ef08b4 100644
--- a/src/test/run-make/thumb-none-qemu/example/src/main.rs
+++ b/src/test/run-make/thumb-none-qemu/example/src/main.rs
@@ -27,4 +27,4 @@ fn main() -> ! {
         // exit from qemu
         semihosting::debug::exit(semihosting::debug::EXIT_SUCCESS);
     }
-}
\ No newline at end of file
+}

From 06d0a715b564a656e8e272307c5915f0f65ae040 Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Tue, 16 Oct 2018 21:42:42 +0900
Subject: [PATCH 23/48] [ci] clean up potentially harmful envs

---
 src/test/run-make/thumb-none-qemu/Makefile | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/test/run-make/thumb-none-qemu/Makefile b/src/test/run-make/thumb-none-qemu/Makefile
index 75c17372bc238..ffd17721b73bb 100644
--- a/src/test/run-make/thumb-none-qemu/Makefile
+++ b/src/test/run-make/thumb-none-qemu/Makefile
@@ -14,14 +14,14 @@ export WORK_DIR := $(TMPDIR)
 export HERE := $(shell pwd)
 
 ## clean up unused env variables which might cause harm.
-# unexport RUSTC_LINKER
-# unexport RUSTC_BOOTSTRAP
-# unexport RUST_BUILD_STAGE
-# unexport RUST_TEST_THREADS
-# unexport RUST_TEST_TMPDIR
-# unexport AR
-# unexport CC
-# unexport CXX
+unexport RUSTC_LINKER
+unexport RUSTC_BOOTSTRAP
+unexport RUST_BUILD_STAGE
+unexport RUST_TEST_THREADS
+unexport RUST_TEST_TMPDIR
+unexport AR
+unexport CC
+unexport CXX
 
 all:
 	bash script.sh

From 7cac7b613d3ad516ce7df66539812bff988d3095 Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Thu, 18 Oct 2018 06:53:17 +0900
Subject: [PATCH 24/48] [ci] run-make/thumb-none-qemu:  use GNU LD.

---
 src/test/run-make/thumb-none-qemu/script.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/test/run-make/thumb-none-qemu/script.sh b/src/test/run-make/thumb-none-qemu/script.sh
index c7133f8fb7fce..d20afefb4a52d 100644
--- a/src/test/run-make/thumb-none-qemu/script.sh
+++ b/src/test/run-make/thumb-none-qemu/script.sh
@@ -8,7 +8,7 @@ pushd $WORK_DIR
     rm -rf $CRATE || echo OK
     cp -a $HERE/example .
     pushd $CRATE
-        $CARGO run --target $TARGET           | grep "x = 42"
-        $CARGO run --target $TARGET --release | grep "x = 42"
+        env RUSTFLAGS="-C linker=arm-none-eabi-ld -C link-arg=-Tlink.x" $CARGO run --target $TARGET           | grep "x = 42"
+        env RUSTFLAGS="-C linker=arm-none-eabi-ld -C link-arg=-Tlink.x" $CARGO run --target $TARGET --release | grep "x = 42"
     popd
 popd

From 35bbcf14f4c83201386268c88cd8014234257667 Mon Sep 17 00:00:00 2001
From: Hideki Sekine <sekineh@me.com>
Date: Fri, 19 Oct 2018 00:36:24 +0900
Subject: [PATCH 25/48] [ci] fix tidy warning.

---
 src/test/run-make/thumb-none-qemu/script.sh | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/test/run-make/thumb-none-qemu/script.sh b/src/test/run-make/thumb-none-qemu/script.sh
index d20afefb4a52d..0f1c49f3a71b1 100644
--- a/src/test/run-make/thumb-none-qemu/script.sh
+++ b/src/test/run-make/thumb-none-qemu/script.sh
@@ -8,7 +8,9 @@ pushd $WORK_DIR
     rm -rf $CRATE || echo OK
     cp -a $HERE/example .
     pushd $CRATE
-        env RUSTFLAGS="-C linker=arm-none-eabi-ld -C link-arg=-Tlink.x" $CARGO run --target $TARGET           | grep "x = 42"
-        env RUSTFLAGS="-C linker=arm-none-eabi-ld -C link-arg=-Tlink.x" $CARGO run --target $TARGET --release | grep "x = 42"
+        env RUSTFLAGS="-C linker=arm-none-eabi-ld -C link-arg=-Tlink.x" \
+            $CARGO run --target $TARGET           | grep "x = 42"
+        env RUSTFLAGS="-C linker=arm-none-eabi-ld -C link-arg=-Tlink.x" \
+            $CARGO run --target $TARGET --release | grep "x = 42"
     popd
 popd

From 9f0a352999bfe4f265d6930a49efee7b80fe6ef5 Mon Sep 17 00:00:00 2001
From: Oliver Scherer <github35764891676564198441@oli-obk.de>
Date: Mon, 22 Oct 2018 15:45:03 +0200
Subject: [PATCH 26/48] Turn ICE for dangling pointers into error

---
 src/librustc_mir/interpret/memory.rs            |  5 +++++
 src/test/ui/consts/dangling-alloc-id-ice.rs     | 15 +++++++++++++++
 src/test/ui/consts/dangling-alloc-id-ice.stderr | 13 +++++++++++++
 3 files changed, 33 insertions(+)
 create mode 100644 src/test/ui/consts/dangling-alloc-id-ice.rs
 create mode 100644 src/test/ui/consts/dangling-alloc-id-ice.stderr

diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs
index 9adca6c429798..954616fe9fcd7 100644
--- a/src/librustc_mir/interpret/memory.rs
+++ b/src/librustc_mir/interpret/memory.rs
@@ -732,6 +732,11 @@ where
             if self.alloc_map.contains_key(&alloc) {
                 // Not yet interned, so proceed recursively
                 self.intern_static(alloc, mutability)?;
+            } else if self.dead_alloc_map.contains_key(&alloc) {
+                // danging pointer
+                return err!(ValidationFailure(
+                    "encountered dangling pointer in final constant".into(),
+                ))
             }
         }
         Ok(())
diff --git a/src/test/ui/consts/dangling-alloc-id-ice.rs b/src/test/ui/consts/dangling-alloc-id-ice.rs
new file mode 100644
index 0000000000000..31fa23ae23221
--- /dev/null
+++ b/src/test/ui/consts/dangling-alloc-id-ice.rs
@@ -0,0 +1,15 @@
+// https://github.com/rust-lang/rust/issues/55223
+
+#![feature(const_let)]
+
+union Foo<'a> {
+    y: &'a (),
+    long_live_the_unit: &'static (),
+}
+
+const FOO: &() = { //~ ERROR this constant cannot be used
+    let y = ();
+    unsafe { Foo { y: &y }.long_live_the_unit }
+};
+
+fn main() {}
diff --git a/src/test/ui/consts/dangling-alloc-id-ice.stderr b/src/test/ui/consts/dangling-alloc-id-ice.stderr
new file mode 100644
index 0000000000000..df623f943addc
--- /dev/null
+++ b/src/test/ui/consts/dangling-alloc-id-ice.stderr
@@ -0,0 +1,13 @@
+error: this constant cannot be used
+  --> $DIR/dangling-alloc-id-ice.rs:10:1
+   |
+LL | / const FOO: &() = { //~ ERROR this constant cannot be used
+LL | |     let y = ();
+LL | |     unsafe { Foo { y: &y }.long_live_the_unit }
+LL | | };
+   | |__^ type validation failed: encountered dangling pointer in final constant
+   |
+   = note: #[deny(const_err)] on by default
+
+error: aborting due to previous error
+

From 0ba126217d4d349e5d9681bbb838c036adb55d18 Mon Sep 17 00:00:00 2001
From: Oliver Scherer <github35764891676564198441@oli-obk.de>
Date: Mon, 22 Oct 2018 18:05:27 +0200
Subject: [PATCH 27/48] Reproduce the underlying issue

nll (and thus the algorithm for actual promotion) don't know about some casts anymore
---
 .../consts/dangling-alloc-id-ice-2.nll.stderr | 30 +++++++++++++++++++
 src/test/ui/consts/dangling-alloc-id-ice-2.rs | 10 +++++++
 .../ui/consts/dangling-alloc-id-ice-2.stderr  | 11 +++++++
 3 files changed, 51 insertions(+)
 create mode 100644 src/test/ui/consts/dangling-alloc-id-ice-2.nll.stderr
 create mode 100644 src/test/ui/consts/dangling-alloc-id-ice-2.rs
 create mode 100644 src/test/ui/consts/dangling-alloc-id-ice-2.stderr

diff --git a/src/test/ui/consts/dangling-alloc-id-ice-2.nll.stderr b/src/test/ui/consts/dangling-alloc-id-ice-2.nll.stderr
new file mode 100644
index 0000000000000..e6ae57796055f
--- /dev/null
+++ b/src/test/ui/consts/dangling-alloc-id-ice-2.nll.stderr
@@ -0,0 +1,30 @@
+warning[E0716]: temporary value dropped while borrowed
+  --> $DIR/dangling-alloc-id-ice-2.rs:5:28
+   |
+LL |    static MAP: Slice = Slice(&[
+   |   ___________________________-^
+   |  |___________________________|
+   | ||
+LL | ||     b"CloseEvent" as &'static [u8],
+LL | || ]);
+   | || -- temporary value is freed at the end of this statement
+   | ||_|
+   | |__creates a temporary which is freed while still in use
+   |    cast requires that borrow lasts for `'static`
+   |
+   = warning: This error has been downgraded to a warning for backwards compatibility with previous releases.
+           It represents potential unsoundness in your code.
+           This warning will become a hard error in the future.
+
+error[E0080]: could not evaluate static initializer
+  --> $DIR/dangling-alloc-id-ice-2.rs:5:1
+   |
+LL | / static MAP: Slice = Slice(&[
+LL | |     b"CloseEvent" as &'static [u8],
+LL | | ]);
+   | |___^ type validation failed: encountered dangling pointer in final constant
+
+error: aborting due to previous error
+
+Some errors occurred: E0080, E0716.
+For more information about an error, try `rustc --explain E0080`.
diff --git a/src/test/ui/consts/dangling-alloc-id-ice-2.rs b/src/test/ui/consts/dangling-alloc-id-ice-2.rs
new file mode 100644
index 0000000000000..9af72c8dc0b83
--- /dev/null
+++ b/src/test/ui/consts/dangling-alloc-id-ice-2.rs
@@ -0,0 +1,10 @@
+// https://github.com/rust-lang/rust/issues/55223
+
+struct Slice(&'static [&'static [u8]]);
+
+static MAP: Slice = Slice(&[
+    b"CloseEvent" as &'static [u8],
+]);
+
+
+fn main() {}
diff --git a/src/test/ui/consts/dangling-alloc-id-ice-2.stderr b/src/test/ui/consts/dangling-alloc-id-ice-2.stderr
new file mode 100644
index 0000000000000..42df542f55cf5
--- /dev/null
+++ b/src/test/ui/consts/dangling-alloc-id-ice-2.stderr
@@ -0,0 +1,11 @@
+error[E0080]: could not evaluate static initializer
+  --> $DIR/dangling-alloc-id-ice-2.rs:5:1
+   |
+LL | / static MAP: Slice = Slice(&[
+LL | |     b"CloseEvent" as &'static [u8],
+LL | | ]);
+   | |___^ type validation failed: encountered dangling pointer in final constant
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0080`.

From 80a6b736acca2c109547e100d217fe5ca5f4ec30 Mon Sep 17 00:00:00 2001
From: Shotaro Yamada <sinkuu@sinkuu.xyz>
Date: Tue, 23 Oct 2018 01:54:02 +0900
Subject: [PATCH 28/48] Unimplement ExactSizeIterator

If root is not START_BLOCK, `basic_blocks().len() - visited` does not represent
their exact size.
---
 src/librustc/mir/traversal.rs | 36 +++++++++++++++++++++++------------
 1 file changed, 24 insertions(+), 12 deletions(-)

diff --git a/src/librustc/mir/traversal.rs b/src/librustc/mir/traversal.rs
index db1bc3e7519c2..a1e2b7a06468d 100644
--- a/src/librustc/mir/traversal.rs
+++ b/src/librustc/mir/traversal.rs
@@ -34,6 +34,7 @@ pub struct Preorder<'a, 'tcx: 'a> {
     mir: &'a Mir<'tcx>,
     visited: BitSet<BasicBlock>,
     worklist: Vec<BasicBlock>,
+    root_is_start_block: bool,
 }
 
 impl<'a, 'tcx> Preorder<'a, 'tcx> {
@@ -44,6 +45,7 @@ impl<'a, 'tcx> Preorder<'a, 'tcx> {
             mir,
             visited: BitSet::new_empty(mir.basic_blocks().len()),
             worklist,
+            root_is_start_block: root == START_BLOCK,
         }
     }
 }
@@ -75,15 +77,19 @@ impl<'a, 'tcx> Iterator for Preorder<'a, 'tcx> {
 
     fn size_hint(&self) -> (usize, Option<usize>) {
         // All the blocks, minus the number of blocks we've visited.
-        let remaining = self.mir.basic_blocks().len() - self.visited.count();
+        let upper = self.mir.basic_blocks().len() - self.visited.count();
 
-        // We will visit all remaining blocks exactly once.
-        (remaining, Some(remaining))
+        let lower = if self.root_is_start_block {
+            // We will visit all remaining blocks exactly once.
+            upper
+        } else {
+            self.worklist.len()
+        };
+
+        (lower, Some(upper))
     }
 }
 
-impl<'a, 'tcx> ExactSizeIterator for Preorder<'a, 'tcx> {}
-
 /// Postorder traversal of a graph.
 ///
 /// Postorder traversal is when each node is visited after all of it's
@@ -105,7 +111,8 @@ impl<'a, 'tcx> ExactSizeIterator for Preorder<'a, 'tcx> {}
 pub struct Postorder<'a, 'tcx: 'a> {
     mir: &'a Mir<'tcx>,
     visited: BitSet<BasicBlock>,
-    visit_stack: Vec<(BasicBlock, Successors<'a>)>
+    visit_stack: Vec<(BasicBlock, Successors<'a>)>,
+    root_is_start_block: bool,
 }
 
 impl<'a, 'tcx> Postorder<'a, 'tcx> {
@@ -113,7 +120,8 @@ impl<'a, 'tcx> Postorder<'a, 'tcx> {
         let mut po = Postorder {
             mir,
             visited: BitSet::new_empty(mir.basic_blocks().len()),
-            visit_stack: Vec::new()
+            visit_stack: Vec::new(),
+            root_is_start_block: root == START_BLOCK,
         };
 
 
@@ -214,15 +222,19 @@ impl<'a, 'tcx> Iterator for Postorder<'a, 'tcx> {
 
     fn size_hint(&self) -> (usize, Option<usize>) {
         // All the blocks, minus the number of blocks we've visited.
-        let remaining = self.mir.basic_blocks().len() - self.visited.count();
+        let upper = self.mir.basic_blocks().len() - self.visited.count();
 
-        // We will visit all remaining blocks exactly once.
-        (remaining, Some(remaining))
+        let lower = if self.root_is_start_block {
+            // We will visit all remaining blocks exactly once.
+            upper
+        } else {
+            self.visit_stack.len()
+        };
+
+        (lower, Some(upper))
     }
 }
 
-impl<'a, 'tcx> ExactSizeIterator for Postorder<'a, 'tcx> {}
-
 /// Reverse postorder traversal of a graph
 ///
 /// Reverse postorder is the reverse order of a postorder traversal.

From b5336c0b9755f635db4eafba6254e192ee451e6a Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <nnethercote@mozilla.com>
Date: Thu, 18 Oct 2018 09:11:11 +1100
Subject: [PATCH 29/48] Add a cheap mode for `compute_missing_ctors`.

`compute_missing_ctors` is called a lot. It produces a vector, which can
be reasonably large (e.g. 100+ elements), but the vector is almost
always only checked for emptiness.

This commit changes `compute_missing_ctors` so it can be called in a
cheap way that just indicates if the vector would be empty. If
necessary, the function can subsequently be called in an expensive way
to compute the full vector.

This change reduces instruction counts for several benchmarks up to 2%.
---
 src/librustc_mir/hair/pattern/_match.rs | 85 +++++++++++++++++++------
 1 file changed, 66 insertions(+), 19 deletions(-)

diff --git a/src/librustc_mir/hair/pattern/_match.rs b/src/librustc_mir/hair/pattern/_match.rs
index aa1c6902dce33..7f46e2f384551 100644
--- a/src/librustc_mir/hair/pattern/_match.rs
+++ b/src/librustc_mir/hair/pattern/_match.rs
@@ -931,12 +931,37 @@ impl<'tcx> IntRange<'tcx> {
     }
 }
 
-// Return a set of constructors equivalent to `all_ctors \ used_ctors`.
+// A request for missing constructor data in terms of either:
+// - whether or not there any missing constructors; or
+// - the actual set of missing constructors.
+#[derive(PartialEq)]
+enum MissingCtorsInfo {
+    Emptiness,
+    Ctors,
+}
+
+// Used by `compute_missing_ctors`.
+#[derive(Debug, PartialEq)]
+enum MissingCtors<'tcx> {
+    Empty,
+    NonEmpty,
+
+    // Note that the Vec can be empty.
+    Ctors(Vec<Constructor<'tcx>>),
+}
+
+// When `info` is `MissingCtorsInfo::Ctors`, compute a set of constructors
+// equivalent to `all_ctors \ used_ctors`. When `info` is
+// `MissingCtorsInfo::Emptiness`, just determines if that set is empty or not.
+// (The split logic gives a performance win, because we always need to know if
+// the set is empty, but we rarely need the full set, and it can be expensive
+// to compute the full set.)
 fn compute_missing_ctors<'a, 'tcx: 'a>(
+    info: MissingCtorsInfo,
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     all_ctors: &Vec<Constructor<'tcx>>,
     used_ctors: &Vec<Constructor<'tcx>>,
-) -> Vec<Constructor<'tcx>> {
+) -> MissingCtors<'tcx> {
     let mut missing_ctors = vec![];
 
     for req_ctor in all_ctors {
@@ -965,10 +990,22 @@ fn compute_missing_ctors<'a, 'tcx: 'a>(
         // We add `refined_ctors` instead of `req_ctor`, because then we can
         // provide more detailed error information about precisely which
         // ranges have been omitted.
-        missing_ctors.extend(refined_ctors);
+        if info == MissingCtorsInfo::Emptiness {
+            if !refined_ctors.is_empty() {
+                // The set is non-empty; return early.
+                return MissingCtors::NonEmpty;
+            }
+        } else {
+            missing_ctors.extend(refined_ctors);
+        }
     }
 
-    missing_ctors
+    if info == MissingCtorsInfo::Emptiness {
+        // If we reached here, the set is empty.
+        MissingCtors::Empty
+    } else {
+        MissingCtors::Ctors(missing_ctors)
+    }
 }
 
 /// Algorithm from http://moscova.inria.fr/~maranget/papers/warn/index.html
@@ -1081,20 +1118,23 @@ pub fn is_useful<'p, 'a: 'p, 'tcx: 'a>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
         // feature flag is not present, so this is only
         // needed for that case.
 
-        // Find those constructors that are not matched by any non-wildcard patterns in the
-        // current column.
-        let missing_ctors = compute_missing_ctors(cx.tcx, &all_ctors, &used_ctors);
+        // Missing constructors are those that are not matched by any
+        // non-wildcard patterns in the current column. We always determine if
+        // the set is empty, but we only fully construct them on-demand,
+        // because they're rarely used and can be big.
+        let cheap_missing_ctors =
+            compute_missing_ctors(MissingCtorsInfo::Emptiness, cx.tcx, &all_ctors, &used_ctors);
 
         let is_privately_empty = all_ctors.is_empty() && !cx.is_uninhabited(pcx.ty);
         let is_declared_nonexhaustive = cx.is_non_exhaustive_enum(pcx.ty) && !cx.is_local(pcx.ty);
-        debug!("missing_ctors={:#?} is_privately_empty={:#?} is_declared_nonexhaustive={:#?}",
-               missing_ctors, is_privately_empty, is_declared_nonexhaustive);
+        debug!("cheap_missing_ctors={:#?} is_privately_empty={:#?} is_declared_nonexhaustive={:#?}",
+               cheap_missing_ctors, is_privately_empty, is_declared_nonexhaustive);
 
         // For privately empty and non-exhaustive enums, we work as if there were an "extra"
         // `_` constructor for the type, so we can never match over all constructors.
         let is_non_exhaustive = is_privately_empty || is_declared_nonexhaustive;
 
-        if missing_ctors.is_empty() && !is_non_exhaustive {
+        if cheap_missing_ctors == MissingCtors::Empty && !is_non_exhaustive {
             split_grouped_constructors(cx.tcx, all_ctors, matrix, pcx.ty).into_iter().map(|c| {
                 is_useful_specialized(cx, matrix, v, c.clone(), pcx.ty, witness)
             }).find(|result| result.is_useful()).unwrap_or(NotUseful)
@@ -1165,15 +1205,22 @@ pub fn is_useful<'p, 'a: 'p, 'tcx: 'a>(cx: &mut MatchCheckCtxt<'a, 'tcx>,
                             witness
                         }).collect()
                     } else {
-                        pats.into_iter().flat_map(|witness| {
-                            missing_ctors.iter().map(move |ctor| {
-                                // Extends the witness with a "wild" version of this
-                                // constructor, that matches everything that can be built with
-                                // it. For example, if `ctor` is a `Constructor::Variant` for
-                                // `Option::Some`, this pushes the witness for `Some(_)`.
-                                witness.clone().push_wild_constructor(cx, ctor, pcx.ty)
-                            })
-                        }).collect()
+                        let expensive_missing_ctors =
+                            compute_missing_ctors(MissingCtorsInfo::Ctors, cx.tcx, &all_ctors,
+                                                  &used_ctors);
+                        if let MissingCtors::Ctors(missing_ctors) = expensive_missing_ctors {
+                            pats.into_iter().flat_map(|witness| {
+                                missing_ctors.iter().map(move |ctor| {
+                                    // Extends the witness with a "wild" version of this
+                                    // constructor, that matches everything that can be built with
+                                    // it. For example, if `ctor` is a `Constructor::Variant` for
+                                    // `Option::Some`, this pushes the witness for `Some(_)`.
+                                    witness.clone().push_wild_constructor(cx, ctor, pcx.ty)
+                                })
+                            }).collect()
+                        } else {
+                            bug!("cheap missing ctors")
+                        }
                     };
                     UsefulWithWitness(new_witnesses)
                 }

From 4f2624cac90ee9145175d6e4b9c59b9ab7875a9c Mon Sep 17 00:00:00 2001
From: Aaron Hill <aa1ronham@gmail.com>
Date: Mon, 22 Oct 2018 00:12:16 -0400
Subject: [PATCH 30/48] Fix Rustdoc ICE when checking blanket impls

Fixes #55001, #54744

Previously, SelectionContext would unconditionally cache the selection
result for an obligation. This worked fine for most users of
SelectionContext, but it caused an issue when used by Rustdoc's blanket
impl finder.

The issue occured when SelectionContext chose a ParamCandidate which
contained inference variables. Since inference variables can change
between calls to select(), it's not safe to cache the selection result -
the chosen candidate might not be applicable for future results, leading
to an ICE when we try to run confirmation.

This commit prevents SelectionContext from caching any ParamCandidate
that contains inference variables. This should always be completely
safe, as trait selection should never depend on a particular result
being cached.

I've also added some extra debug!() statements, which I found helpful in
tracking down this bug.
---
 src/librustc/infer/combine.rs        | 10 +++++++-
 src/librustc/infer/equate.rs         |  3 +++
 src/librustc/traits/select.rs        | 35 ++++++++++++++++++++++++++++
 src/librustdoc/clean/blanket_impl.rs | 11 +++++++--
 src/test/rustdoc/issue-55001.rs      | 31 ++++++++++++++++++++++++
 5 files changed, 87 insertions(+), 3 deletions(-)
 create mode 100644 src/test/rustdoc/issue-55001.rs

diff --git a/src/librustc/infer/combine.rs b/src/librustc/infer/combine.rs
index de8f57ee79666..0ee03bc4c6e00 100644
--- a/src/librustc/infer/combine.rs
+++ b/src/librustc/infer/combine.rs
@@ -251,6 +251,7 @@ impl<'infcx, 'gcx, 'tcx> CombineFields<'infcx, 'gcx, 'tcx> {
                   dir: RelationDir)
                   -> RelateResult<'tcx, Generalization<'tcx>>
     {
+        debug!("generalize(ty={:?}, for_vid={:?}, dir={:?}", ty, for_vid, dir);
         // Determine the ambient variance within which `ty` appears.
         // The surrounding equation is:
         //
@@ -273,8 +274,15 @@ impl<'infcx, 'gcx, 'tcx> CombineFields<'infcx, 'gcx, 'tcx> {
             root_ty: ty,
         };
 
-        let ty = generalize.relate(&ty, &ty)?;
+        let ty = match generalize.relate(&ty, &ty) {
+            Ok(ty) => ty,
+            Err(e) => {
+                debug!("generalize: failure {:?}", e);
+                return Err(e);
+            }
+        };
         let needs_wf = generalize.needs_wf;
+        debug!("generalize: success {{ {:?}, {:?} }}", ty, needs_wf);
         Ok(Generalization { ty, needs_wf })
     }
 }
diff --git a/src/librustc/infer/equate.rs b/src/librustc/infer/equate.rs
index 854960492c9bd..c7b5ddb83410f 100644
--- a/src/librustc/infer/equate.rs
+++ b/src/librustc/infer/equate.rs
@@ -74,6 +74,9 @@ impl<'combine, 'infcx, 'gcx, 'tcx> TypeRelation<'infcx, 'gcx, 'tcx>
         let infcx = self.fields.infcx;
         let a = infcx.type_variables.borrow_mut().replace_if_possible(a);
         let b = infcx.type_variables.borrow_mut().replace_if_possible(b);
+
+        debug!("{}.tys: replacements ({:?}, {:?})", self.tag(), a, b);
+
         match (&a.sty, &b.sty) {
             (&ty::Infer(TyVar(a_id)), &ty::Infer(TyVar(b_id))) => {
                 infcx.type_variables.borrow_mut().equate(a_id, b_id);
diff --git a/src/librustc/traits/select.rs b/src/librustc/traits/select.rs
index 39c623de677d3..3f4aa3a500d71 100644
--- a/src/librustc/traits/select.rs
+++ b/src/librustc/traits/select.rs
@@ -1522,6 +1522,33 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
             .map(|v| v.get(tcx))
     }
 
+    /// Determines whether can we safely cache the result
+    /// of selecting an obligation. This is almost always 'true',
+    /// except when dealing with certain ParamCandidates.
+    ///
+    /// Ordinarily, a ParamCandidate will contain no inference variables,
+    /// since it was usually produced directly from a DefId. However,
+    /// certain cases (currently only librustdoc's blanket impl finder),
+    /// a ParamEnv may be explicitly constructed with inference types.
+    /// When this is the case, we do *not* want to cache the resulting selection
+    /// candidate. This is due to the fact that it might not always be possible
+    /// to equate the obligation's trait ref and the candidate's trait ref,
+    /// if more constraints end up getting added to an inference variable.
+    ///
+    /// Because of this, we always want to re-run the full selection
+    /// process for our obligation the next time we see it, since
+    /// we might end up picking a different SelectionCandidate (or none at all)
+    fn can_cache_candidate(&self,
+        result: &SelectionResult<'tcx, SelectionCandidate<'tcx>>
+     ) -> bool {
+        match result {
+            Ok(Some(SelectionCandidate::ParamCandidate(trait_ref))) => {
+                !trait_ref.skip_binder().input_types().any(|t| t.walk().any(|t_| t_.is_ty_infer()))
+            },
+            _ => true
+        }
+    }
+
     fn insert_candidate_cache(
         &mut self,
         param_env: ty::ParamEnv<'tcx>,
@@ -1531,6 +1558,14 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
     ) {
         let tcx = self.tcx();
         let trait_ref = cache_fresh_trait_pred.skip_binder().trait_ref;
+
+        if !self.can_cache_candidate(&candidate) {
+            debug!("insert_candidate_cache(trait_ref={:?}, candidate={:?} -\
+                    candidate is not cacheable", trait_ref, candidate);
+            return;
+
+        }
+
         if self.can_use_global_caches(param_env) {
             if let Err(Overflow) = candidate {
                 // Don't cache overflow globally; we only produce this
diff --git a/src/librustdoc/clean/blanket_impl.rs b/src/librustdoc/clean/blanket_impl.rs
index b6bc8d603d5ac..57c7e2afd625e 100644
--- a/src/librustdoc/clean/blanket_impl.rs
+++ b/src/librustdoc/clean/blanket_impl.rs
@@ -50,6 +50,7 @@ impl<'a, 'tcx, 'rcx, 'cstore> BlanketImplFinder <'a, 'tcx, 'rcx, 'cstore> {
         name: Option<String>,
     ) -> Vec<Item>
     where F: Fn(DefId) -> Def {
+        debug!("get_blanket_impls(def_id={:?}, ...)", def_id);
         let mut impls = Vec::new();
         if self.cx
             .tcx
@@ -78,6 +79,8 @@ impl<'a, 'tcx, 'rcx, 'cstore> BlanketImplFinder <'a, 'tcx, 'rcx, 'cstore> {
             }
             self.cx.tcx.for_each_relevant_impl(trait_def_id, ty, |impl_def_id| {
                 self.cx.tcx.infer_ctxt().enter(|infcx| {
+                    debug!("get_blanet_impls: Considering impl for trait '{:?}' {:?}",
+                           trait_def_id, impl_def_id);
                     let t_generics = infcx.tcx.generics_of(impl_def_id);
                     let trait_ref = infcx.tcx.impl_trait_ref(impl_def_id)
                                              .expect("Cannot get impl trait");
@@ -104,8 +107,8 @@ impl<'a, 'tcx, 'rcx, 'cstore> BlanketImplFinder <'a, 'tcx, 'rcx, 'cstore> {
                         drop(obligations);
 
                         debug!(
-                            "invoking predicate_may_hold: {:?}",
-                            trait_ref,
+                            "invoking predicate_may_hold: param_env={:?}, trait_ref={:?}, ty={:?}",
+                             param_env, trait_ref, ty
                         );
                         let may_apply = match infcx.evaluate_obligation(
                             &traits::Obligation::new(
@@ -117,6 +120,10 @@ impl<'a, 'tcx, 'rcx, 'cstore> BlanketImplFinder <'a, 'tcx, 'rcx, 'cstore> {
                             Ok(eval_result) => eval_result.may_apply(),
                             Err(traits::OverflowError) => true, // overflow doesn't mean yes *or* no
                         };
+                        debug!("get_blanket_impls: found applicable impl: {}\
+                               for trait_ref={:?}, ty={:?}",
+                               may_apply, trait_ref, ty);
+
                         if !may_apply {
                             return
                         }
diff --git a/src/test/rustdoc/issue-55001.rs b/src/test/rustdoc/issue-55001.rs
new file mode 100644
index 0000000000000..f6c7f9a3d082c
--- /dev/null
+++ b/src/test/rustdoc/issue-55001.rs
@@ -0,0 +1,31 @@
+// Regression test for issue #55001. Previously, we would incorrectly
+// cache certain trait selection results when checking for blanket impls,
+// resulting in an ICE when we tried to confirm the cached ParamCandidate
+// against an obligation.
+
+pub struct DefaultAllocator;
+pub struct Standard;
+pub struct Inner;
+
+pub trait Rand {}
+
+pub trait Distribution<T> {}
+pub trait Allocator<N> {}
+
+impl<T> Rand for T where Standard: Distribution<T> {}
+
+impl<A> Distribution<Point<A>> for Standard
+where
+DefaultAllocator: Allocator<A>,
+Standard: Distribution<A> {}
+
+impl Distribution<Inner> for Standard {}
+
+
+pub struct Point<N>
+where DefaultAllocator: Allocator<N>
+{
+    field: N
+}
+
+fn main() {}

From 2d960a561061d78d44c3c56d3aa0fa6975ca0ce7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Oliver=20S=CC=B6c=CC=B6h=CC=B6n=CC=B6e=CC=B6i=CC=B6d=CC=B6?=
 =?UTF-8?q?e=CC=B6r=20Scherer?= <github35764891676564198441@oli-obk.de>
Date: Tue, 23 Oct 2018 13:39:30 +0200
Subject: [PATCH 31/48] Update dangling-alloc-id-ice-2.rs

---
 src/test/ui/consts/dangling-alloc-id-ice-2.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/test/ui/consts/dangling-alloc-id-ice-2.rs b/src/test/ui/consts/dangling-alloc-id-ice-2.rs
index 9af72c8dc0b83..b4691641fc98f 100644
--- a/src/test/ui/consts/dangling-alloc-id-ice-2.rs
+++ b/src/test/ui/consts/dangling-alloc-id-ice-2.rs
@@ -1,4 +1,4 @@
-// https://github.com/rust-lang/rust/issues/55223
+// FIXME(#55223) this is just a reproduction test showing the wrong behavior
 
 struct Slice(&'static [&'static [u8]]);
 

From 8544db0faa9e0f7a70323ad5f3e75358bba6820d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Tue, 23 Oct 2018 10:07:11 -0700
Subject: [PATCH 32/48] Add macro call span when lacking any other span in
 diagnostic

---
 src/libsyntax/ext/tt/macro_rules.rs                   |  7 ++++++-
 src/libsyntax_pos/lib.rs                              | 11 +++++++++++
 src/test/ui/macros/macro-in-expression-context-2.rs   |  7 +++++++
 .../ui/macros/macro-in-expression-context-2.stderr    |  8 ++++++++
 4 files changed, 32 insertions(+), 1 deletion(-)
 create mode 100644 src/test/ui/macros/macro-in-expression-context-2.rs
 create mode 100644 src/test/ui/macros/macro-in-expression-context-2.stderr

diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 87ade278c685a..b70a7989275cc 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -50,7 +50,12 @@ pub struct ParserAnyMacro<'a> {
 impl<'a> ParserAnyMacro<'a> {
     pub fn make(mut self: Box<ParserAnyMacro<'a>>, kind: AstFragmentKind) -> AstFragment {
         let ParserAnyMacro { site_span, macro_ident, ref mut parser } = *self;
-        let fragment = panictry!(parser.parse_ast_fragment(kind, true));
+        let fragment = panictry!(parser.parse_ast_fragment(kind, true).map_err(|mut e| {
+            if e.span.is_dummy() {  // Get around lack of span in error (#30128)
+                e.set_span(site_span);
+            }
+            e
+        }));
 
         // We allow semicolons at the end of expressions -- e.g. the semicolon in
         // `macro_rules! m { () => { panic!(); } }` isn't parsed by `.parse_expr()`,
diff --git a/src/libsyntax_pos/lib.rs b/src/libsyntax_pos/lib.rs
index 45eaf1d3190f2..639155636edfa 100644
--- a/src/libsyntax_pos/lib.rs
+++ b/src/libsyntax_pos/lib.rs
@@ -612,6 +612,17 @@ impl MultiSpan {
         &self.primary_spans
     }
 
+    /// Returns `true` if this contains only a dummy primary span with any hygienic context.
+    pub fn is_dummy(&self) -> bool {
+        let mut is_dummy = true;
+        for span in &self.primary_spans {
+            if !span.is_dummy() {
+                is_dummy = false;
+            }
+        }
+        is_dummy
+    }
+
     /// Replaces all occurrences of one Span with another. Used to move Spans in areas that don't
     /// display well (like std macros). Returns true if replacements occurred.
     pub fn replace(&mut self, before: Span, after: Span) -> bool {
diff --git a/src/test/ui/macros/macro-in-expression-context-2.rs b/src/test/ui/macros/macro-in-expression-context-2.rs
new file mode 100644
index 0000000000000..cf8572aefa242
--- /dev/null
+++ b/src/test/ui/macros/macro-in-expression-context-2.rs
@@ -0,0 +1,7 @@
+macro_rules! empty { () => () }
+
+fn main() {
+    match 42 {
+        _ => { empty!() }
+    };
+}
diff --git a/src/test/ui/macros/macro-in-expression-context-2.stderr b/src/test/ui/macros/macro-in-expression-context-2.stderr
new file mode 100644
index 0000000000000..80d5dbd66cc29
--- /dev/null
+++ b/src/test/ui/macros/macro-in-expression-context-2.stderr
@@ -0,0 +1,8 @@
+error: expected expression, found `<eof>`
+  --> $DIR/macro-in-expression-context-2.rs:5:16
+   |
+LL |         _ => { empty!() }
+   |                ^^^^^^^^
+
+error: aborting due to previous error
+

From ad144ac3c1da0d4a25d8ca95113ac6f29bc0fce5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Tue, 23 Oct 2018 10:07:34 -0700
Subject: [PATCH 33/48] Modify invalid macro in expression context diagnostic

---
 src/libsyntax/ext/expand.rs                   | 24 ++++++++++++---
 src/test/ui/issues/issue-30007.stderr         |  9 +++---
 src/test/ui/macros/macro-context.stderr       | 29 +++++++++----------
 .../macros/macro-in-expression-context.fixed  | 15 ++++++++++
 .../ui/macros/macro-in-expression-context.rs  | 15 ++++++++++
 .../macros/macro-in-expression-context.stderr | 15 ++++++++++
 .../macro/macro-incomplete-parse.stderr       | 18 +++++-------
 7 files changed, 91 insertions(+), 34 deletions(-)
 create mode 100644 src/test/ui/macros/macro-in-expression-context.fixed
 create mode 100644 src/test/ui/macros/macro-in-expression-context.rs
 create mode 100644 src/test/ui/macros/macro-in-expression-context.stderr

diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 9e06384f5a804..436e0b53a7691 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -1036,10 +1036,26 @@ impl<'a> Parser<'a> {
             // Avoid emitting backtrace info twice.
             let def_site_span = self.span.with_ctxt(SyntaxContext::empty());
             let mut err = self.diagnostic().struct_span_err(def_site_span, &msg);
-            let msg = format!("caused by the macro expansion here; the usage \
-                               of `{}!` is likely invalid in {} context",
-                               macro_path, kind_name);
-            err.span_note(span, &msg).emit();
+            err.span_label(span, "caused by the macro expansion here");
+            let msg = format!(
+                "the usage of `{}!` is likely invalid in {} context",
+                macro_path,
+                kind_name,
+            );
+            err.note(&msg);
+            let semi_span = self.sess.source_map().next_point(span);
+            match self.sess.source_map().span_to_snippet(semi_span) {
+                Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
+                    err.span_suggestion_with_applicability(
+                        semi_span,
+                        "you might be missing a semicolon here",
+                        ";".to_owned(),
+                        Applicability::MaybeIncorrect,
+                    );
+                }
+                _ => {}
+            }
+            err.emit();
         }
     }
 }
diff --git a/src/test/ui/issues/issue-30007.stderr b/src/test/ui/issues/issue-30007.stderr
index a467ff6dd0a1a..028ed048d6525 100644
--- a/src/test/ui/issues/issue-30007.stderr
+++ b/src/test/ui/issues/issue-30007.stderr
@@ -3,12 +3,11 @@ error: macro expansion ignores token `;` and any following
    |
 LL |     () => ( String ; );     //~ ERROR macro expansion ignores token `;`
    |                    ^
-   |
-note: caused by the macro expansion here; the usage of `t!` is likely invalid in type context
-  --> $DIR/issue-30007.rs:16:16
-   |
+...
 LL |     let i: Vec<t!()>;
-   |                ^^^^
+   |                ---- caused by the macro expansion here
+   |
+   = note: the usage of `t!` is likely invalid in type context
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/macros/macro-context.stderr b/src/test/ui/macros/macro-context.stderr
index b3e67fb2607cd..5ea7825080c24 100644
--- a/src/test/ui/macros/macro-context.stderr
+++ b/src/test/ui/macros/macro-context.stderr
@@ -3,36 +3,35 @@ error: macro expansion ignores token `;` and any following
    |
 LL |     () => ( i ; typeof );   //~ ERROR expected expression, found reserved keyword `typeof`
    |               ^
-   |
-note: caused by the macro expansion here; the usage of `m!` is likely invalid in type context
-  --> $DIR/macro-context.rs:20:12
-   |
+...
 LL |     let a: m!();
-   |            ^^^^
+   |            ---- caused by the macro expansion here
+   |
+   = note: the usage of `m!` is likely invalid in type context
 
 error: macro expansion ignores token `typeof` and any following
   --> $DIR/macro-context.rs:13:17
    |
 LL |     () => ( i ; typeof );   //~ ERROR expected expression, found reserved keyword `typeof`
    |                 ^^^^^^
-   |
-note: caused by the macro expansion here; the usage of `m!` is likely invalid in expression context
-  --> $DIR/macro-context.rs:21:13
-   |
+...
 LL |     let i = m!();
-   |             ^^^^
+   |             ----- help: you might be missing a semicolon here: `;`
+   |             |
+   |             caused by the macro expansion here
+   |
+   = note: the usage of `m!` is likely invalid in expression context
 
 error: macro expansion ignores token `;` and any following
   --> $DIR/macro-context.rs:13:15
    |
 LL |     () => ( i ; typeof );   //~ ERROR expected expression, found reserved keyword `typeof`
    |               ^
-   |
-note: caused by the macro expansion here; the usage of `m!` is likely invalid in pattern context
-  --> $DIR/macro-context.rs:23:9
-   |
+...
 LL |         m!() => {}
-   |         ^^^^
+   |         ---- caused by the macro expansion here
+   |
+   = note: the usage of `m!` is likely invalid in pattern context
 
 error: expected expression, found reserved keyword `typeof`
   --> $DIR/macro-context.rs:13:17
diff --git a/src/test/ui/macros/macro-in-expression-context.fixed b/src/test/ui/macros/macro-in-expression-context.fixed
new file mode 100644
index 0000000000000..df36db0f49e72
--- /dev/null
+++ b/src/test/ui/macros/macro-in-expression-context.fixed
@@ -0,0 +1,15 @@
+// run-rustfix
+
+macro_rules! foo {
+    () => {
+        assert_eq!("A", "A");
+        assert_eq!("B", "B");
+    }
+    //~^^ ERROR macro expansion ignores token `assert_eq` and any following
+    //~| NOTE the usage of `foo!` is likely invalid in expression context
+}
+
+fn main() {
+    foo!();
+    //~^ NOTE caused by the macro expansion here
+}
diff --git a/src/test/ui/macros/macro-in-expression-context.rs b/src/test/ui/macros/macro-in-expression-context.rs
new file mode 100644
index 0000000000000..b3f5e568967e8
--- /dev/null
+++ b/src/test/ui/macros/macro-in-expression-context.rs
@@ -0,0 +1,15 @@
+// run-rustfix
+
+macro_rules! foo {
+    () => {
+        assert_eq!("A", "A");
+        assert_eq!("B", "B");
+    }
+    //~^^ ERROR macro expansion ignores token `assert_eq` and any following
+    //~| NOTE the usage of `foo!` is likely invalid in expression context
+}
+
+fn main() {
+    foo!()
+    //~^ NOTE caused by the macro expansion here
+}
diff --git a/src/test/ui/macros/macro-in-expression-context.stderr b/src/test/ui/macros/macro-in-expression-context.stderr
new file mode 100644
index 0000000000000..d27d6fbaef7a6
--- /dev/null
+++ b/src/test/ui/macros/macro-in-expression-context.stderr
@@ -0,0 +1,15 @@
+error: macro expansion ignores token `assert_eq` and any following
+  --> $DIR/macro-in-expression-context.rs:6:9
+   |
+LL |         assert_eq!("B", "B");
+   |         ^^^^^^^^^
+...
+LL |     foo!()
+   |     ------- help: you might be missing a semicolon here: `;`
+   |     |
+   |     caused by the macro expansion here
+   |
+   = note: the usage of `foo!` is likely invalid in expression context
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/macro/macro-incomplete-parse.stderr b/src/test/ui/parser/macro/macro-incomplete-parse.stderr
index 198730dc07a99..806aca511d0ae 100644
--- a/src/test/ui/parser/macro/macro-incomplete-parse.stderr
+++ b/src/test/ui/parser/macro/macro-incomplete-parse.stderr
@@ -3,12 +3,11 @@ error: macro expansion ignores token `,` and any following
    |
 LL |         , //~ ERROR macro expansion ignores token `,`
    |         ^
-   |
-note: caused by the macro expansion here; the usage of `ignored_item!` is likely invalid in item context
-  --> $DIR/macro-incomplete-parse.rs:31:1
-   |
+...
 LL | ignored_item!();
-   | ^^^^^^^^^^^^^^^^
+   | ---------------- caused by the macro expansion here
+   |
+   = note: the usage of `ignored_item!` is likely invalid in item context
 
 error: expected one of `.`, `;`, `?`, `}`, or an operator, found `,`
   --> $DIR/macro-incomplete-parse.rs:22:14
@@ -24,12 +23,11 @@ error: macro expansion ignores token `,` and any following
    |
 LL |     () => ( 1, 2 ) //~ ERROR macro expansion ignores token `,`
    |              ^
-   |
-note: caused by the macro expansion here; the usage of `ignored_pat!` is likely invalid in pattern context
-  --> $DIR/macro-incomplete-parse.rs:36:9
-   |
+...
 LL |         ignored_pat!() => (),
-   |         ^^^^^^^^^^^^^^
+   |         -------------- caused by the macro expansion here
+   |
+   = note: the usage of `ignored_pat!` is likely invalid in pattern context
 
 error: aborting due to 3 previous errors
 

From 8227a938a4970008ec333f6cd66be9d4be0e981c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Tue, 23 Oct 2018 17:18:14 -0700
Subject: [PATCH 34/48] Point at macro definition when no rules expect token

---
 src/libsyntax/ext/base.rs                     | 18 +++-
 src/libsyntax/ext/expand.rs                   |  9 +-
 src/libsyntax/ext/tt/macro_rules.rs           | 25 +++--
 .../auxiliary/plugin_args.rs                  |  3 +-
 .../edition-keywords-2015-2015-parsing.stderr |  4 +-
 .../edition-keywords-2015-2018-parsing.stderr |  4 +-
 .../edition-keywords-2018-2015-parsing.stderr |  4 +-
 .../edition-keywords-2018-2018-parsing.stderr |  4 +-
 src/test/ui/empty/empty-comment.stderr        |  9 +-
 src/test/ui/fail-simple.stderr                |  2 +-
 src/test/ui/issues/issue-7970a.stderr         |  9 +-
 ...-at-most-once-rep-2018-feature-gate.stderr | 33 +++++--
 .../macros/macro-at-most-once-rep-2018.stderr | 99 ++++++++++++++-----
 src/test/ui/macros/macro-non-lifetime.stderr  |  5 +-
 src/test/ui/macros/missing-comma.stderr       | 64 +++++++++---
 .../ui/macros/nonterminal-matching.stderr     |  2 +-
 src/test/ui/macros/trace_faulty_macros.stderr | 13 ++-
 .../parser/macro/macro-doc-comments-1.stderr  |  9 +-
 .../parser/macro/macro-doc-comments-2.stderr  |  9 +-
 src/test/ui/underscore-ident-matcher.stderr   | 11 ++-
 .../ui/vec/vec-macro-with-comma-only.stderr   |  2 +-
 21 files changed, 256 insertions(+), 82 deletions(-)

diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 5bf1a7dd663cc..1701c8da2c5bd 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -247,8 +247,13 @@ impl<F> AttrProcMacro for F
 
 /// Represents a thing that maps token trees to Macro Results
 pub trait TTMacroExpander {
-    fn expand<'cx>(&self, ecx: &'cx mut ExtCtxt, span: Span, input: TokenStream)
-                   -> Box<dyn MacResult+'cx>;
+    fn expand<'cx>(
+        &self,
+        ecx: &'cx mut ExtCtxt,
+        span: Span,
+        input: TokenStream,
+        def_span: Option<Span>,
+    ) -> Box<dyn MacResult+'cx>;
 }
 
 pub type MacroExpanderFn =
@@ -259,8 +264,13 @@ impl<F> TTMacroExpander for F
     where F: for<'cx> Fn(&'cx mut ExtCtxt, Span, &[tokenstream::TokenTree])
     -> Box<dyn MacResult+'cx>
 {
-    fn expand<'cx>(&self, ecx: &'cx mut ExtCtxt, span: Span, input: TokenStream)
-                   -> Box<dyn MacResult+'cx> {
+    fn expand<'cx>(
+        &self,
+        ecx: &'cx mut ExtCtxt,
+        span: Span,
+        input: TokenStream,
+        _def_span: Option<Span>,
+    ) -> Box<dyn MacResult+'cx> {
         struct AvoidInterpolatedIdents;
 
         impl Folder for AvoidInterpolatedIdents {
diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 9e06384f5a804..46ffdf4eba2da 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -764,7 +764,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                                                                     edition) {
                     dummy_span
                 } else {
-                    kind.make_from(expander.expand(self.cx, span, mac.node.stream()))
+                    kind.make_from(expander.expand(self.cx, span, mac.node.stream(), None))
                 }
             }
 
@@ -785,7 +785,12 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                                                                     edition) {
                     dummy_span
                 } else {
-                    kind.make_from(expander.expand(self.cx, span, mac.node.stream()))
+                    kind.make_from(expander.expand(
+                        self.cx,
+                        span,
+                        mac.node.stream(),
+                        def_info.map(|(_, s)| s),
+                    ))
                 }
             }
 
diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 87ade278c685a..41e8cbe550211 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -74,16 +74,19 @@ struct MacroRulesMacroExpander {
 }
 
 impl TTMacroExpander for MacroRulesMacroExpander {
-    fn expand<'cx>(&self,
-                   cx: &'cx mut ExtCtxt,
-                   sp: Span,
-                   input: TokenStream)
-                   -> Box<dyn MacResult+'cx> {
+    fn expand<'cx>(
+        &self,
+        cx: &'cx mut ExtCtxt,
+        sp: Span,
+        input: TokenStream,
+        def_span: Option<Span>,
+    ) -> Box<dyn MacResult+'cx> {
         if !self.valid {
             return DummyResult::any(sp);
         }
         generic_extension(cx,
                           sp,
+                          def_span,
                           self.name,
                           input,
                           &self.lhses,
@@ -99,6 +102,7 @@ fn trace_macros_note(cx: &mut ExtCtxt, sp: Span, message: String) {
 /// Given `lhses` and `rhses`, this is the new macro we create
 fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
                           sp: Span,
+                          def_span: Option<Span>,
                           name: ast::Ident,
                           arg: TokenStream,
                           lhses: &[quoted::TokenTree],
@@ -178,7 +182,14 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
     }
 
     let best_fail_msg = parse_failure_msg(best_fail_tok.expect("ran no matchers"));
-    let mut err = cx.struct_span_err(best_fail_spot.substitute_dummy(sp), &best_fail_msg);
+    let span = best_fail_spot.substitute_dummy(sp);
+    let mut err = cx.struct_span_err(span, &best_fail_msg);
+    err.span_label(span, best_fail_msg);
+    if let Some(sp) = def_span {
+        if cx.source_map().span_to_filename(sp).is_real() && !sp.is_dummy() {
+            err.span_label(sp, "when calling this macro");
+        }
+    }
 
     // Check whether there's a missing comma in this macro call, like `println!("{}" a);`
     if let Some((arg, comma_span)) = arg.add_comma() {
@@ -189,7 +200,7 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
             };
             match TokenTree::parse(cx, lhs_tt, arg.clone()) {
                 Success(_) => {
-                    if comma_span == DUMMY_SP {
+                    if comma_span.is_dummy() {
                         err.note("you might be missing a comma");
                     } else {
                         err.span_suggestion_short_with_applicability(
diff --git a/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs b/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs
index ac39118c5f1e0..27169299c8a69 100644
--- a/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs
+++ b/src/test/run-pass-fulldeps/auxiliary/plugin_args.rs
@@ -38,7 +38,8 @@ impl TTMacroExpander for Expander {
     fn expand<'cx>(&self,
                    ecx: &'cx mut ExtCtxt,
                    sp: Span,
-                   _: TokenStream) -> Box<MacResult+'cx> {
+                   _: TokenStream,
+                   _: Option<Span>) -> Box<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)))
diff --git a/src/test/ui/editions/edition-keywords-2015-2015-parsing.stderr b/src/test/ui/editions/edition-keywords-2015-2015-parsing.stderr
index a629d13e6c31b..e8f05cbb0ef70 100644
--- a/src/test/ui/editions/edition-keywords-2015-2015-parsing.stderr
+++ b/src/test/ui/editions/edition-keywords-2015-2015-parsing.stderr
@@ -2,13 +2,13 @@ error: no rules expected the token `r#async`
   --> $DIR/edition-keywords-2015-2015-parsing.rs:22:31
    |
 LL |     r#async = consumes_async!(r#async); //~ ERROR no rules expected the token `r#async`
-   |                               ^^^^^^^
+   |                               ^^^^^^^ no rules expected the token `r#async`
 
 error: no rules expected the token `async`
   --> $DIR/edition-keywords-2015-2015-parsing.rs:23:35
    |
 LL |     r#async = consumes_async_raw!(async); //~ ERROR no rules expected the token `async`
-   |                                   ^^^^^
+   |                                   ^^^^^ no rules expected the token `async`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/editions/edition-keywords-2015-2018-parsing.stderr b/src/test/ui/editions/edition-keywords-2015-2018-parsing.stderr
index ab8a34a4a9e3d..3f5e1137383dd 100644
--- a/src/test/ui/editions/edition-keywords-2015-2018-parsing.stderr
+++ b/src/test/ui/editions/edition-keywords-2015-2018-parsing.stderr
@@ -2,13 +2,13 @@ error: no rules expected the token `r#async`
   --> $DIR/edition-keywords-2015-2018-parsing.rs:22:31
    |
 LL |     r#async = consumes_async!(r#async); //~ ERROR no rules expected the token `r#async`
-   |                               ^^^^^^^
+   |                               ^^^^^^^ no rules expected the token `r#async`
 
 error: no rules expected the token `async`
   --> $DIR/edition-keywords-2015-2018-parsing.rs:23:35
    |
 LL |     r#async = consumes_async_raw!(async); //~ ERROR no rules expected the token `async`
-   |                                   ^^^^^
+   |                                   ^^^^^ no rules expected the token `async`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/editions/edition-keywords-2018-2015-parsing.stderr b/src/test/ui/editions/edition-keywords-2018-2015-parsing.stderr
index 5955410aa106b..b6ff60f1492ea 100644
--- a/src/test/ui/editions/edition-keywords-2018-2015-parsing.stderr
+++ b/src/test/ui/editions/edition-keywords-2018-2015-parsing.stderr
@@ -14,13 +14,13 @@ error: no rules expected the token `r#async`
   --> $DIR/edition-keywords-2018-2015-parsing.rs:22:31
    |
 LL |     r#async = consumes_async!(r#async); //~ ERROR no rules expected the token `r#async`
-   |                               ^^^^^^^
+   |                               ^^^^^^^ no rules expected the token `r#async`
 
 error: no rules expected the token `async`
   --> $DIR/edition-keywords-2018-2015-parsing.rs:23:35
    |
 LL |     r#async = consumes_async_raw!(async); //~ ERROR no rules expected the token `async`
-   |                                   ^^^^^
+   |                                   ^^^^^ no rules expected the token `async`
 
 error: expected one of `move`, `|`, or `||`, found `<eof>`
   --> <::edition_kw_macro_2015::passes_ident macros>:1:22
diff --git a/src/test/ui/editions/edition-keywords-2018-2018-parsing.stderr b/src/test/ui/editions/edition-keywords-2018-2018-parsing.stderr
index 6ea736828f907..ffe666a7e6442 100644
--- a/src/test/ui/editions/edition-keywords-2018-2018-parsing.stderr
+++ b/src/test/ui/editions/edition-keywords-2018-2018-parsing.stderr
@@ -14,13 +14,13 @@ error: no rules expected the token `r#async`
   --> $DIR/edition-keywords-2018-2018-parsing.rs:22:31
    |
 LL |     r#async = consumes_async!(r#async); //~ ERROR no rules expected the token `r#async`
-   |                               ^^^^^^^
+   |                               ^^^^^^^ no rules expected the token `r#async`
 
 error: no rules expected the token `async`
   --> $DIR/edition-keywords-2018-2018-parsing.rs:23:35
    |
 LL |     r#async = consumes_async_raw!(async); //~ ERROR no rules expected the token `async`
-   |                                   ^^^^^
+   |                                   ^^^^^ no rules expected the token `async`
 
 error: expected one of `move`, `|`, or `||`, found `<eof>`
   --> <::edition_kw_macro_2018::passes_ident macros>:1:22
diff --git a/src/test/ui/empty/empty-comment.stderr b/src/test/ui/empty/empty-comment.stderr
index d6990c4eaeb8f..e15f347f49d9c 100644
--- a/src/test/ui/empty/empty-comment.stderr
+++ b/src/test/ui/empty/empty-comment.stderr
@@ -1,8 +1,13 @@
 error: unexpected end of macro invocation
   --> $DIR/empty-comment.rs:20:5
    |
-LL |     one_arg_macro!(/**/); //~ ERROR unexpected end
-   |     ^^^^^^^^^^^^^^^^^^^^^
+LL | / macro_rules! one_arg_macro {
+LL | |     ($fmt:expr) => (print!(concat!($fmt, "/n")));
+LL | | }
+   | |_- when calling this macro
+...
+LL |       one_arg_macro!(/**/); //~ ERROR unexpected end
+   |       ^^^^^^^^^^^^^^^^^^^^^ unexpected end of macro invocation
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/fail-simple.stderr b/src/test/ui/fail-simple.stderr
index 764f2c464bcb8..4a4aec5b6ac57 100644
--- a/src/test/ui/fail-simple.stderr
+++ b/src/test/ui/fail-simple.stderr
@@ -2,7 +2,7 @@ error: no rules expected the token `@`
   --> $DIR/fail-simple.rs:12:12
    |
 LL |     panic!(@); //~ ERROR no rules expected the token `@`
-   |            ^
+   |            ^ no rules expected the token `@`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-7970a.stderr b/src/test/ui/issues/issue-7970a.stderr
index 7ad95717185b8..94beebf514e17 100644
--- a/src/test/ui/issues/issue-7970a.stderr
+++ b/src/test/ui/issues/issue-7970a.stderr
@@ -1,8 +1,13 @@
 error: unexpected end of macro invocation
   --> $DIR/issue-7970a.rs:16:5
    |
-LL |     one_arg_macro!();
-   |     ^^^^^^^^^^^^^^^^^
+LL | / macro_rules! one_arg_macro {
+LL | |     ($fmt:expr) => (print!(concat!($fmt, "/n")));
+LL | | }
+   | |_- when calling this macro
+...
+LL |       one_arg_macro!();
+   |       ^^^^^^^^^^^^^^^^^ unexpected end of macro invocation
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/macros/macro-at-most-once-rep-2018-feature-gate.stderr b/src/test/ui/macros/macro-at-most-once-rep-2018-feature-gate.stderr
index 22f1c94fced6f..6f77eb634399b 100644
--- a/src/test/ui/macros/macro-at-most-once-rep-2018-feature-gate.stderr
+++ b/src/test/ui/macros/macro-at-most-once-rep-2018-feature-gate.stderr
@@ -51,20 +51,41 @@ LL |     ($(a)?*) => {}
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018-feature-gate.rs:41:11
    |
-LL |     foo!(a?); //~ ERROR no rules expected the token `?`
-   |           ^
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | |     //~^ERROR using the `?` macro Kleene operator for
+LL | |     //~|ERROR expected `*` or `+`
+LL | | }
+   | |_- when calling this macro
+...
+LL |       foo!(a?); //~ ERROR no rules expected the token `?`
+   |             ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018-feature-gate.rs:42:11
    |
-LL |     foo!(a?a); //~ ERROR no rules expected the token `?`
-   |           ^
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | |     //~^ERROR using the `?` macro Kleene operator for
+LL | |     //~|ERROR expected `*` or `+`
+LL | | }
+   | |_- when calling this macro
+...
+LL |       foo!(a?a); //~ ERROR no rules expected the token `?`
+   |             ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018-feature-gate.rs:43:11
    |
-LL |     foo!(a?a?a); //~ ERROR no rules expected the token `?`
-   |           ^
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | |     //~^ERROR using the `?` macro Kleene operator for
+LL | |     //~|ERROR expected `*` or `+`
+LL | | }
+   | |_- when calling this macro
+...
+LL |       foo!(a?a?a); //~ ERROR no rules expected the token `?`
+   |             ^ no rules expected the token `?`
 
 error: aborting due to 10 previous errors
 
diff --git a/src/test/ui/macros/macro-at-most-once-rep-2018.stderr b/src/test/ui/macros/macro-at-most-once-rep-2018.stderr
index 0a15bdb10686d..3bdfae5ccdf7f 100644
--- a/src/test/ui/macros/macro-at-most-once-rep-2018.stderr
+++ b/src/test/ui/macros/macro-at-most-once-rep-2018.stderr
@@ -7,68 +7,123 @@ LL |     ($(a),?) => {} //~ERROR the `?` macro repetition operator
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:36:11
    |
-LL |     foo!(a?); //~ ERROR no rules expected the token `?`
-   |           ^
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | | }
+   | |_- when calling this macro
+...
+LL |       foo!(a?); //~ ERROR no rules expected the token `?`
+   |             ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:37:11
    |
-LL |     foo!(a?a); //~ ERROR no rules expected the token `?`
-   |           ^
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | | }
+   | |_- when calling this macro
+...
+LL |       foo!(a?a); //~ ERROR no rules expected the token `?`
+   |             ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:38:11
    |
-LL |     foo!(a?a?a); //~ ERROR no rules expected the token `?`
-   |           ^
+LL | / macro_rules! foo {
+LL | |     ($(a)?) => {}
+LL | | }
+   | |_- when calling this macro
+...
+LL |       foo!(a?a?a); //~ ERROR no rules expected the token `?`
+   |             ^ no rules expected the token `?`
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:40:5
    |
-LL |     barplus!(); //~ERROR unexpected end of macro invocation
-   |     ^^^^^^^^^^^
+LL | / macro_rules! barplus {
+LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
+LL | | }
+   | |_- when calling this macro
+...
+LL |       barplus!(); //~ERROR unexpected end of macro invocation
+   |       ^^^^^^^^^^^ unexpected end of macro invocation
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:41:14
    |
-LL |     barplus!(a); //~ERROR unexpected end of macro invocation
-   |              ^
+LL | / macro_rules! barplus {
+LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
+LL | | }
+   | |_- when calling this macro
+...
+LL |       barplus!(a); //~ERROR unexpected end of macro invocation
+   |                ^ unexpected end of macro invocation
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:42:15
    |
-LL |     barplus!(a?); //~ ERROR no rules expected the token `?`
-   |               ^
+LL | / macro_rules! barplus {
+LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
+LL | | }
+   | |_- when calling this macro
+...
+LL |       barplus!(a?); //~ ERROR no rules expected the token `?`
+   |                 ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:43:15
    |
-LL |     barplus!(a?a); //~ ERROR no rules expected the token `?`
-   |               ^
+LL | / macro_rules! barplus {
+LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
+LL | | }
+   | |_- when calling this macro
+...
+LL |       barplus!(a?a); //~ ERROR no rules expected the token `?`
+   |                 ^ no rules expected the token `?`
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:47:5
    |
-LL |     barstar!(); //~ERROR unexpected end of macro invocation
-   |     ^^^^^^^^^^^
+LL | / macro_rules! barstar {
+LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
+LL | | }
+   | |_- when calling this macro
+...
+LL |       barstar!(); //~ERROR unexpected end of macro invocation
+   |       ^^^^^^^^^^^ unexpected end of macro invocation
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:48:14
    |
-LL |     barstar!(a); //~ERROR unexpected end of macro invocation
-   |              ^
+LL | / macro_rules! barstar {
+LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
+LL | | }
+   | |_- when calling this macro
+...
+LL |       barstar!(a); //~ERROR unexpected end of macro invocation
+   |                ^ unexpected end of macro invocation
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:49:15
    |
-LL |     barstar!(a?); //~ ERROR no rules expected the token `?`
-   |               ^
+LL | / macro_rules! barstar {
+LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
+LL | | }
+   | |_- when calling this macro
+...
+LL |       barstar!(a?); //~ ERROR no rules expected the token `?`
+   |                 ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:50:15
    |
-LL |     barstar!(a?a); //~ ERROR no rules expected the token `?`
-   |               ^
+LL | / macro_rules! barstar {
+LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
+LL | | }
+   | |_- when calling this macro
+...
+LL |       barstar!(a?a); //~ ERROR no rules expected the token `?`
+   |                 ^ no rules expected the token `?`
 
 error: aborting due to 12 previous errors
 
diff --git a/src/test/ui/macros/macro-non-lifetime.stderr b/src/test/ui/macros/macro-non-lifetime.stderr
index 93b7f481842ac..48a93010c3b6f 100644
--- a/src/test/ui/macros/macro-non-lifetime.stderr
+++ b/src/test/ui/macros/macro-non-lifetime.stderr
@@ -1,8 +1,11 @@
 error: no rules expected the token `a`
   --> $DIR/macro-non-lifetime.rs:18:8
    |
+LL | macro_rules! m { ($x:lifetime) => { } }
+   | --------------------------------------- when calling this macro
+...
 LL |     m!(a);
-   |        ^
+   |        ^ no rules expected the token `a`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/macros/missing-comma.stderr b/src/test/ui/macros/missing-comma.stderr
index 9d8de87e5bb7f..5548be86a1300 100644
--- a/src/test/ui/macros/missing-comma.stderr
+++ b/src/test/ui/macros/missing-comma.stderr
@@ -7,32 +7,68 @@ LL |     println!("{}" a);
 error: no rules expected the token `b`
   --> $DIR/missing-comma.rs:22:12
    |
-LL |     foo!(a b);
-   |           -^
-   |           |
-   |           help: missing comma here
+LL | / macro_rules! foo {
+LL | |     ($a:ident) => ();
+LL | |     ($a:ident, $b:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
+LL | | }
+   | |_- when calling this macro
+...
+LL |       foo!(a b);
+   |             -^ no rules expected the token `b`
+   |             |
+   |             help: missing comma here
 
 error: no rules expected the token `e`
   --> $DIR/missing-comma.rs:24:21
    |
-LL |     foo!(a, b, c, d e);
-   |                    -^
-   |                    |
-   |                    help: missing comma here
+LL | / macro_rules! foo {
+LL | |     ($a:ident) => ();
+LL | |     ($a:ident, $b:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
+LL | | }
+   | |_- when calling this macro
+...
+LL |       foo!(a, b, c, d e);
+   |                      -^ no rules expected the token `e`
+   |                      |
+   |                      help: missing comma here
 
 error: no rules expected the token `d`
   --> $DIR/missing-comma.rs:26:18
    |
-LL |     foo!(a, b, c d, e);
-   |                 -^
-   |                 |
-   |                 help: missing comma here
+LL | / macro_rules! foo {
+LL | |     ($a:ident) => ();
+LL | |     ($a:ident, $b:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
+LL | | }
+   | |_- when calling this macro
+...
+LL |       foo!(a, b, c d, e);
+   |                   -^ no rules expected the token `d`
+   |                   |
+   |                   help: missing comma here
 
 error: no rules expected the token `d`
   --> $DIR/missing-comma.rs:28:18
    |
-LL |     foo!(a, b, c d e);
-   |                  ^
+LL | / macro_rules! foo {
+LL | |     ($a:ident) => ();
+LL | |     ($a:ident, $b:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
+LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
+LL | | }
+   | |_- when calling this macro
+...
+LL |       foo!(a, b, c d e);
+   |                    ^ no rules expected the token `d`
 
 error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/macros/nonterminal-matching.stderr b/src/test/ui/macros/nonterminal-matching.stderr
index bf2221d52a492..23853978d371b 100644
--- a/src/test/ui/macros/nonterminal-matching.stderr
+++ b/src/test/ui/macros/nonterminal-matching.stderr
@@ -2,7 +2,7 @@ error: no rules expected the token `enum E { }`
   --> $DIR/nonterminal-matching.rs:29:10
    |
 LL |     n!(a $nt_item b); //~ ERROR no rules expected the token `enum E { }`
-   |          ^^^^^^^^
+   |          ^^^^^^^^ no rules expected the token `enum E { }`
 ...
 LL | complex_nonterminal!(enum E {});
    | -------------------------------- in this macro invocation
diff --git a/src/test/ui/macros/trace_faulty_macros.stderr b/src/test/ui/macros/trace_faulty_macros.stderr
index a9ffef8ef8090..ecc3694d120fa 100644
--- a/src/test/ui/macros/trace_faulty_macros.stderr
+++ b/src/test/ui/macros/trace_faulty_macros.stderr
@@ -1,11 +1,16 @@
 error: no rules expected the token `bcd`
   --> $DIR/trace_faulty_macros.rs:17:26
    |
-LL |         my_faulty_macro!(bcd); //~ ERROR no rules
-   |                          ^^^
+LL | / macro_rules! my_faulty_macro {
+LL | |     () => {
+LL | |         my_faulty_macro!(bcd); //~ ERROR no rules
+   | |                          ^^^ no rules expected the token `bcd`
+LL | |     };
+LL | | }
+   | |_- when calling this macro
 ...
-LL |     my_faulty_macro!();
-   |     ------------------- in this macro invocation
+LL |       my_faulty_macro!();
+   |       ------------------- in this macro invocation
 
 note: trace_macro
   --> $DIR/trace_faulty_macros.rs:43:5
diff --git a/src/test/ui/parser/macro/macro-doc-comments-1.stderr b/src/test/ui/parser/macro/macro-doc-comments-1.stderr
index a7fdd28b0cab8..4fcc56ac832eb 100644
--- a/src/test/ui/parser/macro/macro-doc-comments-1.stderr
+++ b/src/test/ui/parser/macro/macro-doc-comments-1.stderr
@@ -1,8 +1,13 @@
 error: no rules expected the token `!`
   --> $DIR/macro-doc-comments-1.rs:16:5
    |
-LL |     //! Inner
-   |     ^^^^^^^^^
+LL | / macro_rules! outer {
+LL | |     (#[$outer:meta]) => ()
+LL | | }
+   | |_- when calling this macro
+...
+LL |       //! Inner
+   |       ^^^^^^^^^ no rules expected the token `!`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/macro/macro-doc-comments-2.stderr b/src/test/ui/parser/macro/macro-doc-comments-2.stderr
index bae9823b9b2fa..b34e99fbd9e77 100644
--- a/src/test/ui/parser/macro/macro-doc-comments-2.stderr
+++ b/src/test/ui/parser/macro/macro-doc-comments-2.stderr
@@ -1,8 +1,13 @@
 error: no rules expected the token `[`
   --> $DIR/macro-doc-comments-2.rs:16:5
    |
-LL |     /// Outer
-   |     ^
+LL | / macro_rules! inner {
+LL | |     (#![$inner:meta]) => ()
+LL | | }
+   | |_- when calling this macro
+...
+LL |       /// Outer
+   |       ^ no rules expected the token `[`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/underscore-ident-matcher.stderr b/src/test/ui/underscore-ident-matcher.stderr
index 7f2b6ac30b0da..19d489db5723f 100644
--- a/src/test/ui/underscore-ident-matcher.stderr
+++ b/src/test/ui/underscore-ident-matcher.stderr
@@ -1,8 +1,15 @@
 error: no rules expected the token `_`
   --> $DIR/underscore-ident-matcher.rs:18:19
    |
-LL |     let identity!(_) = 10; //~ ERROR no rules expected the token `_`
-   |                   ^
+LL | / macro_rules! identity {
+LL | |     ($i: ident) => (
+LL | |         $i
+LL | |     )
+LL | | }
+   | |_- when calling this macro
+...
+LL |       let identity!(_) = 10; //~ ERROR no rules expected the token `_`
+   |                     ^ no rules expected the token `_`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/vec/vec-macro-with-comma-only.stderr b/src/test/ui/vec/vec-macro-with-comma-only.stderr
index f5341ccc31286..856d85ef5cdaa 100644
--- a/src/test/ui/vec/vec-macro-with-comma-only.stderr
+++ b/src/test/ui/vec/vec-macro-with-comma-only.stderr
@@ -2,7 +2,7 @@ error: no rules expected the token `,`
   --> $DIR/vec-macro-with-comma-only.rs:12:10
    |
 LL |     vec![,]; //~ ERROR no rules expected the token `,`
-   |          ^
+   |          ^ no rules expected the token `,`
 
 error: aborting due to previous error
 

From 1ab45ec7e366f6f16a6a3d0a58cacb0ee48ef406 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Wed, 24 Oct 2018 11:34:23 -0700
Subject: [PATCH 35/48] Point to macro def span instead of whole body

---
 src/libsyntax/ext/tt/macro_rules.rs           |   2 +-
 src/test/ui/empty/empty-comment.stderr        |  10 +-
 src/test/ui/issues/issue-7970a.stderr         |  10 +-
 ...-at-most-once-rep-2018-feature-gate.stderr |  36 ++----
 .../macros/macro-at-most-once-rep-2018.stderr | 110 +++++++-----------
 src/test/ui/macros/macro-non-lifetime.stderr  |   2 +-
 src/test/ui/macros/missing-comma.stderr       |  68 ++++-------
 src/test/ui/macros/trace_faulty_macros.stderr |  16 ++-
 .../parser/macro/macro-doc-comments-1.stderr  |  10 +-
 .../parser/macro/macro-doc-comments-2.stderr  |  10 +-
 src/test/ui/underscore-ident-matcher.stderr   |  12 +-
 11 files changed, 107 insertions(+), 179 deletions(-)

diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 41e8cbe550211..03fb89b21a43c 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -187,7 +187,7 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
     err.span_label(span, best_fail_msg);
     if let Some(sp) = def_span {
         if cx.source_map().span_to_filename(sp).is_real() && !sp.is_dummy() {
-            err.span_label(sp, "when calling this macro");
+            err.span_label(cx.source_map().def_span(sp), "when calling this macro");
         }
     }
 
diff --git a/src/test/ui/empty/empty-comment.stderr b/src/test/ui/empty/empty-comment.stderr
index e15f347f49d9c..de826102081e7 100644
--- a/src/test/ui/empty/empty-comment.stderr
+++ b/src/test/ui/empty/empty-comment.stderr
@@ -1,13 +1,11 @@
 error: unexpected end of macro invocation
   --> $DIR/empty-comment.rs:20:5
    |
-LL | / macro_rules! one_arg_macro {
-LL | |     ($fmt:expr) => (print!(concat!($fmt, "/n")));
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! one_arg_macro {
+   | -------------------------- when calling this macro
 ...
-LL |       one_arg_macro!(/**/); //~ ERROR unexpected end
-   |       ^^^^^^^^^^^^^^^^^^^^^ unexpected end of macro invocation
+LL |     one_arg_macro!(/**/); //~ ERROR unexpected end
+   |     ^^^^^^^^^^^^^^^^^^^^^ unexpected end of macro invocation
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-7970a.stderr b/src/test/ui/issues/issue-7970a.stderr
index 94beebf514e17..96fb374b58c6c 100644
--- a/src/test/ui/issues/issue-7970a.stderr
+++ b/src/test/ui/issues/issue-7970a.stderr
@@ -1,13 +1,11 @@
 error: unexpected end of macro invocation
   --> $DIR/issue-7970a.rs:16:5
    |
-LL | / macro_rules! one_arg_macro {
-LL | |     ($fmt:expr) => (print!(concat!($fmt, "/n")));
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! one_arg_macro {
+   | -------------------------- when calling this macro
 ...
-LL |       one_arg_macro!();
-   |       ^^^^^^^^^^^^^^^^^ unexpected end of macro invocation
+LL |     one_arg_macro!();
+   |     ^^^^^^^^^^^^^^^^^ unexpected end of macro invocation
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/macros/macro-at-most-once-rep-2018-feature-gate.stderr b/src/test/ui/macros/macro-at-most-once-rep-2018-feature-gate.stderr
index 6f77eb634399b..7705ba3b11ed5 100644
--- a/src/test/ui/macros/macro-at-most-once-rep-2018-feature-gate.stderr
+++ b/src/test/ui/macros/macro-at-most-once-rep-2018-feature-gate.stderr
@@ -51,41 +51,29 @@ LL |     ($(a)?*) => {}
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018-feature-gate.rs:41:11
    |
-LL | / macro_rules! foo {
-LL | |     ($(a)?) => {}
-LL | |     //~^ERROR using the `?` macro Kleene operator for
-LL | |     //~|ERROR expected `*` or `+`
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! foo {
+   | ---------------- when calling this macro
 ...
-LL |       foo!(a?); //~ ERROR no rules expected the token `?`
-   |             ^ no rules expected the token `?`
+LL |     foo!(a?); //~ ERROR no rules expected the token `?`
+   |           ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018-feature-gate.rs:42:11
    |
-LL | / macro_rules! foo {
-LL | |     ($(a)?) => {}
-LL | |     //~^ERROR using the `?` macro Kleene operator for
-LL | |     //~|ERROR expected `*` or `+`
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! foo {
+   | ---------------- when calling this macro
 ...
-LL |       foo!(a?a); //~ ERROR no rules expected the token `?`
-   |             ^ no rules expected the token `?`
+LL |     foo!(a?a); //~ ERROR no rules expected the token `?`
+   |           ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018-feature-gate.rs:43:11
    |
-LL | / macro_rules! foo {
-LL | |     ($(a)?) => {}
-LL | |     //~^ERROR using the `?` macro Kleene operator for
-LL | |     //~|ERROR expected `*` or `+`
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! foo {
+   | ---------------- when calling this macro
 ...
-LL |       foo!(a?a?a); //~ ERROR no rules expected the token `?`
-   |             ^ no rules expected the token `?`
+LL |     foo!(a?a?a); //~ ERROR no rules expected the token `?`
+   |           ^ no rules expected the token `?`
 
 error: aborting due to 10 previous errors
 
diff --git a/src/test/ui/macros/macro-at-most-once-rep-2018.stderr b/src/test/ui/macros/macro-at-most-once-rep-2018.stderr
index 3bdfae5ccdf7f..25dd66b81f567 100644
--- a/src/test/ui/macros/macro-at-most-once-rep-2018.stderr
+++ b/src/test/ui/macros/macro-at-most-once-rep-2018.stderr
@@ -7,123 +7,101 @@ LL |     ($(a),?) => {} //~ERROR the `?` macro repetition operator
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:36:11
    |
-LL | / macro_rules! foo {
-LL | |     ($(a)?) => {}
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! foo {
+   | ---------------- when calling this macro
 ...
-LL |       foo!(a?); //~ ERROR no rules expected the token `?`
-   |             ^ no rules expected the token `?`
+LL |     foo!(a?); //~ ERROR no rules expected the token `?`
+   |           ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:37:11
    |
-LL | / macro_rules! foo {
-LL | |     ($(a)?) => {}
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! foo {
+   | ---------------- when calling this macro
 ...
-LL |       foo!(a?a); //~ ERROR no rules expected the token `?`
-   |             ^ no rules expected the token `?`
+LL |     foo!(a?a); //~ ERROR no rules expected the token `?`
+   |           ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:38:11
    |
-LL | / macro_rules! foo {
-LL | |     ($(a)?) => {}
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! foo {
+   | ---------------- when calling this macro
 ...
-LL |       foo!(a?a?a); //~ ERROR no rules expected the token `?`
-   |             ^ no rules expected the token `?`
+LL |     foo!(a?a?a); //~ ERROR no rules expected the token `?`
+   |           ^ no rules expected the token `?`
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:40:5
    |
-LL | / macro_rules! barplus {
-LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! barplus {
+   | -------------------- when calling this macro
 ...
-LL |       barplus!(); //~ERROR unexpected end of macro invocation
-   |       ^^^^^^^^^^^ unexpected end of macro invocation
+LL |     barplus!(); //~ERROR unexpected end of macro invocation
+   |     ^^^^^^^^^^^ unexpected end of macro invocation
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:41:14
    |
-LL | / macro_rules! barplus {
-LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! barplus {
+   | -------------------- when calling this macro
 ...
-LL |       barplus!(a); //~ERROR unexpected end of macro invocation
-   |                ^ unexpected end of macro invocation
+LL |     barplus!(a); //~ERROR unexpected end of macro invocation
+   |              ^ unexpected end of macro invocation
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:42:15
    |
-LL | / macro_rules! barplus {
-LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! barplus {
+   | -------------------- when calling this macro
 ...
-LL |       barplus!(a?); //~ ERROR no rules expected the token `?`
-   |                 ^ no rules expected the token `?`
+LL |     barplus!(a?); //~ ERROR no rules expected the token `?`
+   |               ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:43:15
    |
-LL | / macro_rules! barplus {
-LL | |     ($(a)?+) => {} // ok. matches "a+" and "+"
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! barplus {
+   | -------------------- when calling this macro
 ...
-LL |       barplus!(a?a); //~ ERROR no rules expected the token `?`
-   |                 ^ no rules expected the token `?`
+LL |     barplus!(a?a); //~ ERROR no rules expected the token `?`
+   |               ^ no rules expected the token `?`
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:47:5
    |
-LL | / macro_rules! barstar {
-LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! barstar {
+   | -------------------- when calling this macro
 ...
-LL |       barstar!(); //~ERROR unexpected end of macro invocation
-   |       ^^^^^^^^^^^ unexpected end of macro invocation
+LL |     barstar!(); //~ERROR unexpected end of macro invocation
+   |     ^^^^^^^^^^^ unexpected end of macro invocation
 
 error: unexpected end of macro invocation
   --> $DIR/macro-at-most-once-rep-2018.rs:48:14
    |
-LL | / macro_rules! barstar {
-LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! barstar {
+   | -------------------- when calling this macro
 ...
-LL |       barstar!(a); //~ERROR unexpected end of macro invocation
-   |                ^ unexpected end of macro invocation
+LL |     barstar!(a); //~ERROR unexpected end of macro invocation
+   |              ^ unexpected end of macro invocation
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:49:15
    |
-LL | / macro_rules! barstar {
-LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! barstar {
+   | -------------------- when calling this macro
 ...
-LL |       barstar!(a?); //~ ERROR no rules expected the token `?`
-   |                 ^ no rules expected the token `?`
+LL |     barstar!(a?); //~ ERROR no rules expected the token `?`
+   |               ^ no rules expected the token `?`
 
 error: no rules expected the token `?`
   --> $DIR/macro-at-most-once-rep-2018.rs:50:15
    |
-LL | / macro_rules! barstar {
-LL | |     ($(a)?*) => {} // ok. matches "a*" and "*"
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! barstar {
+   | -------------------- when calling this macro
 ...
-LL |       barstar!(a?a); //~ ERROR no rules expected the token `?`
-   |                 ^ no rules expected the token `?`
+LL |     barstar!(a?a); //~ ERROR no rules expected the token `?`
+   |               ^ no rules expected the token `?`
 
 error: aborting due to 12 previous errors
 
diff --git a/src/test/ui/macros/macro-non-lifetime.stderr b/src/test/ui/macros/macro-non-lifetime.stderr
index 48a93010c3b6f..d526023d441b1 100644
--- a/src/test/ui/macros/macro-non-lifetime.stderr
+++ b/src/test/ui/macros/macro-non-lifetime.stderr
@@ -2,7 +2,7 @@ error: no rules expected the token `a`
   --> $DIR/macro-non-lifetime.rs:18:8
    |
 LL | macro_rules! m { ($x:lifetime) => { } }
-   | --------------------------------------- when calling this macro
+   | -------------- when calling this macro
 ...
 LL |     m!(a);
    |        ^ no rules expected the token `a`
diff --git a/src/test/ui/macros/missing-comma.stderr b/src/test/ui/macros/missing-comma.stderr
index 5548be86a1300..1d6af44bd08a5 100644
--- a/src/test/ui/macros/missing-comma.stderr
+++ b/src/test/ui/macros/missing-comma.stderr
@@ -7,68 +7,44 @@ LL |     println!("{}" a);
 error: no rules expected the token `b`
   --> $DIR/missing-comma.rs:22:12
    |
-LL | / macro_rules! foo {
-LL | |     ($a:ident) => ();
-LL | |     ($a:ident, $b:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! foo {
+   | ---------------- when calling this macro
 ...
-LL |       foo!(a b);
-   |             -^ no rules expected the token `b`
-   |             |
-   |             help: missing comma here
+LL |     foo!(a b);
+   |           -^ no rules expected the token `b`
+   |           |
+   |           help: missing comma here
 
 error: no rules expected the token `e`
   --> $DIR/missing-comma.rs:24:21
    |
-LL | / macro_rules! foo {
-LL | |     ($a:ident) => ();
-LL | |     ($a:ident, $b:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! foo {
+   | ---------------- when calling this macro
 ...
-LL |       foo!(a, b, c, d e);
-   |                      -^ no rules expected the token `e`
-   |                      |
-   |                      help: missing comma here
+LL |     foo!(a, b, c, d e);
+   |                    -^ no rules expected the token `e`
+   |                    |
+   |                    help: missing comma here
 
 error: no rules expected the token `d`
   --> $DIR/missing-comma.rs:26:18
    |
-LL | / macro_rules! foo {
-LL | |     ($a:ident) => ();
-LL | |     ($a:ident, $b:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! foo {
+   | ---------------- when calling this macro
 ...
-LL |       foo!(a, b, c d, e);
-   |                   -^ no rules expected the token `d`
-   |                   |
-   |                   help: missing comma here
+LL |     foo!(a, b, c d, e);
+   |                 -^ no rules expected the token `d`
+   |                 |
+   |                 help: missing comma here
 
 error: no rules expected the token `d`
   --> $DIR/missing-comma.rs:28:18
    |
-LL | / macro_rules! foo {
-LL | |     ($a:ident) => ();
-LL | |     ($a:ident, $b:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident, $d:ident) => ();
-LL | |     ($a:ident, $b:ident, $c:ident, $d:ident, $e:ident) => ();
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! foo {
+   | ---------------- when calling this macro
 ...
-LL |       foo!(a, b, c d e);
-   |                    ^ no rules expected the token `d`
+LL |     foo!(a, b, c d e);
+   |                  ^ no rules expected the token `d`
 
 error: aborting due to 5 previous errors
 
diff --git a/src/test/ui/macros/trace_faulty_macros.stderr b/src/test/ui/macros/trace_faulty_macros.stderr
index ecc3694d120fa..853eb5847c0cd 100644
--- a/src/test/ui/macros/trace_faulty_macros.stderr
+++ b/src/test/ui/macros/trace_faulty_macros.stderr
@@ -1,16 +1,14 @@
 error: no rules expected the token `bcd`
   --> $DIR/trace_faulty_macros.rs:17:26
    |
-LL | / macro_rules! my_faulty_macro {
-LL | |     () => {
-LL | |         my_faulty_macro!(bcd); //~ ERROR no rules
-   | |                          ^^^ no rules expected the token `bcd`
-LL | |     };
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! my_faulty_macro {
+   | ---------------------------- when calling this macro
+LL |     () => {
+LL |         my_faulty_macro!(bcd); //~ ERROR no rules
+   |                          ^^^ no rules expected the token `bcd`
 ...
-LL |       my_faulty_macro!();
-   |       ------------------- in this macro invocation
+LL |     my_faulty_macro!();
+   |     ------------------- in this macro invocation
 
 note: trace_macro
   --> $DIR/trace_faulty_macros.rs:43:5
diff --git a/src/test/ui/parser/macro/macro-doc-comments-1.stderr b/src/test/ui/parser/macro/macro-doc-comments-1.stderr
index 4fcc56ac832eb..1e765dcde4f68 100644
--- a/src/test/ui/parser/macro/macro-doc-comments-1.stderr
+++ b/src/test/ui/parser/macro/macro-doc-comments-1.stderr
@@ -1,13 +1,11 @@
 error: no rules expected the token `!`
   --> $DIR/macro-doc-comments-1.rs:16:5
    |
-LL | / macro_rules! outer {
-LL | |     (#[$outer:meta]) => ()
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! outer {
+   | ------------------ when calling this macro
 ...
-LL |       //! Inner
-   |       ^^^^^^^^^ no rules expected the token `!`
+LL |     //! Inner
+   |     ^^^^^^^^^ no rules expected the token `!`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/parser/macro/macro-doc-comments-2.stderr b/src/test/ui/parser/macro/macro-doc-comments-2.stderr
index b34e99fbd9e77..0ab8a3cafb55f 100644
--- a/src/test/ui/parser/macro/macro-doc-comments-2.stderr
+++ b/src/test/ui/parser/macro/macro-doc-comments-2.stderr
@@ -1,13 +1,11 @@
 error: no rules expected the token `[`
   --> $DIR/macro-doc-comments-2.rs:16:5
    |
-LL | / macro_rules! inner {
-LL | |     (#![$inner:meta]) => ()
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! inner {
+   | ------------------ when calling this macro
 ...
-LL |       /// Outer
-   |       ^ no rules expected the token `[`
+LL |     /// Outer
+   |     ^ no rules expected the token `[`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/underscore-ident-matcher.stderr b/src/test/ui/underscore-ident-matcher.stderr
index 19d489db5723f..e148c48ed1314 100644
--- a/src/test/ui/underscore-ident-matcher.stderr
+++ b/src/test/ui/underscore-ident-matcher.stderr
@@ -1,15 +1,11 @@
 error: no rules expected the token `_`
   --> $DIR/underscore-ident-matcher.rs:18:19
    |
-LL | / macro_rules! identity {
-LL | |     ($i: ident) => (
-LL | |         $i
-LL | |     )
-LL | | }
-   | |_- when calling this macro
+LL | macro_rules! identity {
+   | --------------------- when calling this macro
 ...
-LL |       let identity!(_) = 10; //~ ERROR no rules expected the token `_`
-   |                     ^ no rules expected the token `_`
+LL |     let identity!(_) = 10; //~ ERROR no rules expected the token `_`
+   |                   ^ no rules expected the token `_`
 
 error: aborting due to previous error
 

From c2463af45d1f2eb03c4b5d5ff2c8842f503832ab Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Oliver=20S=CC=B6c=CC=B6h=CC=B6n=CC=B6e=CC=B6i=CC=B6d=CC=B6?=
 =?UTF-8?q?e=CC=B6r=20Scherer?= <github35764891676564198441@oli-obk.de>
Date: Wed, 24 Oct 2018 20:34:34 +0200
Subject: [PATCH 36/48] Typo

---
 src/librustc_mir/interpret/memory.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs
index 954616fe9fcd7..c28d19158a8c0 100644
--- a/src/librustc_mir/interpret/memory.rs
+++ b/src/librustc_mir/interpret/memory.rs
@@ -733,7 +733,7 @@ where
                 // Not yet interned, so proceed recursively
                 self.intern_static(alloc, mutability)?;
             } else if self.dead_alloc_map.contains_key(&alloc) {
-                // danging pointer
+                // dangling pointer
                 return err!(ValidationFailure(
                     "encountered dangling pointer in final constant".into(),
                 ))

From 569228a45e73ba994d9dc5fff11381fe700d6cc6 Mon Sep 17 00:00:00 2001
From: Steve Klabnik <steve@steveklabnik.com>
Date: Wed, 24 Oct 2018 15:33:48 -0400
Subject: [PATCH 37/48] Fix link to macros chapter

We're gonna link to nightly as this didn't make it into the corresponding stable.
---
 RELEASES.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/RELEASES.md b/RELEASES.md
index 7ae7dc9935b6d..58e49e68b43e7 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -105,7 +105,7 @@ Misc
 [cargo/5878]: https://github.com/rust-lang/cargo/pull/5878/
 [cargo/5984]: https://github.com/rust-lang/cargo/pull/5984/
 [cargo/5995]: https://github.com/rust-lang/cargo/pull/5995/
-[proc-macros]: https://doc.rust-lang.org/book/2018-edition/ch19-06-macros.html
+[proc-macros]: https://doc.rust-lang.org/stable/book/2018-edition/ch19-06-macros.html
 
 [`Ipv4Addr::BROADCAST`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#associatedconstant.BROADCAST
 [`Ipv4Addr::LOCALHOST`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#associatedconstant.LOCALHOST

From f8818cbf8fc30ac626b2a0a306736c1293257209 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Wed, 24 Oct 2018 12:52:24 -0700
Subject: [PATCH 38/48] Fix incorrect semicolon suggestion

---
 src/libsyntax/ext/expand.rs             | 4 +++-
 src/test/ui/macros/macro-context.stderr | 4 +---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs
index 436e0b53a7691..4deeb4a43d994 100644
--- a/src/libsyntax/ext/expand.rs
+++ b/src/libsyntax/ext/expand.rs
@@ -1044,7 +1044,9 @@ impl<'a> Parser<'a> {
             );
             err.note(&msg);
             let semi_span = self.sess.source_map().next_point(span);
-            match self.sess.source_map().span_to_snippet(semi_span) {
+
+            let semi_full_span = semi_span.to(self.sess.source_map().next_point(semi_span));
+            match self.sess.source_map().span_to_snippet(semi_full_span) {
                 Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
                     err.span_suggestion_with_applicability(
                         semi_span,
diff --git a/src/test/ui/macros/macro-context.stderr b/src/test/ui/macros/macro-context.stderr
index 5ea7825080c24..005e1d1c8e7cf 100644
--- a/src/test/ui/macros/macro-context.stderr
+++ b/src/test/ui/macros/macro-context.stderr
@@ -16,9 +16,7 @@ LL |     () => ( i ; typeof );   //~ ERROR expected expression, found reserved k
    |                 ^^^^^^
 ...
 LL |     let i = m!();
-   |             ----- help: you might be missing a semicolon here: `;`
-   |             |
-   |             caused by the macro expansion here
+   |             ---- caused by the macro expansion here
    |
    = note: the usage of `m!` is likely invalid in expression context
 

From bbc3cd43784b69beda25dc0f002514d656d853a2 Mon Sep 17 00:00:00 2001
From: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
Date: Thu, 25 Oct 2018 10:29:08 +0200
Subject: [PATCH 39/48] rustbuild: fix remap-debuginfo when building a release

Fallback to the release number as we can't get the
git commit sha as we're not in a git repository.

Fixes #55341

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>
---
 src/bootstrap/lib.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 4e26c98a62759..ab3d0b51370f1 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -765,7 +765,7 @@ impl Build {
 
         let path = match which {
             GitRepo::Rustc => {
-                let sha = self.rust_info.sha().expect("failed to find sha");
+                let sha = self.rust_sha().unwrap_or(channel::CFG_RELEASE_NUM);
                 format!("/rustc/{}", sha)
             }
             GitRepo::Llvm => format!("/rustc/llvm"),

From ee26e8edebd16b1d11e2af686a12143826fa46fb Mon Sep 17 00:00:00 2001
From: Corey Farwell <coreyf@rwell.org>
Date: Thu, 25 Oct 2018 10:47:07 -0400
Subject: [PATCH 40/48] Update RELEASES.md

Co-Authored-By: steveklabnik <steve@steveklabnik.com>
---
 RELEASES.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/RELEASES.md b/RELEASES.md
index 58e49e68b43e7..729947a9189e0 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -105,7 +105,7 @@ Misc
 [cargo/5878]: https://github.com/rust-lang/cargo/pull/5878/
 [cargo/5984]: https://github.com/rust-lang/cargo/pull/5984/
 [cargo/5995]: https://github.com/rust-lang/cargo/pull/5995/
-[proc-macros]: https://doc.rust-lang.org/stable/book/2018-edition/ch19-06-macros.html
+[proc-macros]: https://doc.rust-lang.org/nightly/book/2018-edition/ch19-06-macros.html
 
 [`Ipv4Addr::BROADCAST`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#associatedconstant.BROADCAST
 [`Ipv4Addr::LOCALHOST`]: https://doc.rust-lang.org/nightly/std/net/struct.Ipv4Addr.html#associatedconstant.LOCALHOST

From f7629eff32cf23680074ae72144ed748139100fe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Oliver=20S=CC=B6c=CC=B6h=CC=B6n=CC=B6e=CC=B6i=CC=B6d=CC=B6?=
 =?UTF-8?q?e=CC=B6r=20Scherer?= <github35764891676564198441@oli-obk.de>
Date: Thu, 25 Oct 2018 18:28:14 +0200
Subject: [PATCH 41/48] Explain a comment in more detail

---
 src/librustc_mir/transform/qualify_consts.rs | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index 4808f02c1dff4..99ccf4f3cf5bb 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -979,8 +979,15 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                     if !constant_arguments.contains(&i) {
                         return
                     }
-                    // if the argument requires a constant, we care about constness, not
-                    // promotability
+                    // Since the argument is required to be constant,
+                    // we care about constness, not promotability.
+                    // If we checked for promotability, we'd miss out on
+                    // the results of function calls (which are never promoted)
+                    // This is not a problem, because the argument explicitly
+                    // requests constness, in contrast to regular promotion
+                    // which happens even without the user requesting it.
+                    // We can error out with a hard error if the argument is not
+                    // constant here.
                     if (this.qualif - Qualif::NOT_PROMOTABLE).is_empty() {
                         this.promotion_candidates.push(candidate);
                     } else {

From 4dc028743dad4d2d71842c2bb20029b412edaca7 Mon Sep 17 00:00:00 2001
From: Oliver Scherer <github35764891676564198441@oli-obk.de>
Date: Thu, 25 Oct 2018 19:37:07 +0200
Subject: [PATCH 42/48] Explain why we can encounter a `Goto` terminator that
 we want to promote

---
 src/librustc_mir/transform/promote_consts.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/librustc_mir/transform/promote_consts.rs b/src/librustc_mir/transform/promote_consts.rs
index bba9260f2b829..1d45850a080d5 100644
--- a/src/librustc_mir/transform/promote_consts.rs
+++ b/src/librustc_mir/transform/promote_consts.rs
@@ -332,7 +332,13 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                             let operand = Operand::Copy(promoted_place(ty, span));
                             mem::replace(&mut args[index], operand)
                         }
-                        // already promoted out
+                        // We expected a `TerminatorKind::Call` for which we'd like to promote an
+                        // argument. Since `qualify_consts` saw a `TerminatorKind::Call` here, but
+                        // we are seeing a `Goto`, that means that the `promote_temps` method
+                        // already promoted this call away entirely. This case occurs when calling
+                        // a function requiring a constant argument and as that constant value
+                        // providing a value whose computation contains another call to a function
+                        // requiring a constant argument.
                         TerminatorKind::Goto { .. } => return,
                         _ => bug!()
                     }

From f4fe9b0a09d1347e26a7f95e78be57360e70c411 Mon Sep 17 00:00:00 2001
From: Oliver Scherer <github35764891676564198441@oli-obk.de>
Date: Thu, 25 Oct 2018 19:39:01 +0200
Subject: [PATCH 43/48] Clarify exclusion comment further

---
 src/librustc_mir/transform/qualify_consts.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index 99ccf4f3cf5bb..1305d02a87b6a 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -982,7 +982,8 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                     // Since the argument is required to be constant,
                     // we care about constness, not promotability.
                     // If we checked for promotability, we'd miss out on
-                    // the results of function calls (which are never promoted)
+                    // the results of function calls (which are never promoted
+                    // in runtime code)
                     // This is not a problem, because the argument explicitly
                     // requests constness, in contrast to regular promotion
                     // which happens even without the user requesting it.

From 2cfd79017744aa55abdd470b93bc544685644612 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Esteban=20K=C3=BCber?= <esteban@kuber.com.ar>
Date: Tue, 23 Oct 2018 21:37:32 -0700
Subject: [PATCH 44/48] List allowed tokens after macro fragments

---
 src/libsyntax/ext/tt/macro_rules.rs           | 138 ++++---
 src/test/ui/macros/macro-follow.stderr        | 340 +++++++++++++-----
 .../macros/macro-followed-by-seq-bad.stderr   |   8 +-
 .../macros/macro-input-future-proofing.stderr |  36 +-
 .../unused-macro-with-follow-violation.stderr |   4 +-
 5 files changed, 385 insertions(+), 141 deletions(-)

diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 805aa9bef227d..a28d114bda784 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -792,15 +792,15 @@ fn check_matcher_core(sess: &ParseSess,
             if let TokenTree::MetaVarDecl(_, ref name, ref frag_spec) = *token {
                 for next_token in &suffix_first.tokens {
                     match is_in_follow(next_token, &frag_spec.as_str()) {
-                        Err((msg, help)) => {
+                        IsInFollow::Invalid(msg, help) => {
                             sess.span_diagnostic.struct_span_err(next_token.span(), &msg)
                                 .help(help).emit();
                             // don't bother reporting every source of
                             // conflict for a particular element of `last`.
                             continue 'each_last;
                         }
-                        Ok(true) => {}
-                        Ok(false) => {
+                        IsInFollow::Yes => {}
+                        IsInFollow::No(ref possible) => {
                             let may_be = if last.tokens.len() == 1 &&
                                 suffix_first.tokens.len() == 1
                             {
@@ -809,15 +809,41 @@ fn check_matcher_core(sess: &ParseSess,
                                 "may be"
                             };
 
-                            sess.span_diagnostic.span_err(
-                                next_token.span(),
+                            let sp = next_token.span();
+                            let mut err = sess.span_diagnostic.struct_span_err(
+                                sp,
                                 &format!("`${name}:{frag}` {may_be} followed by `{next}`, which \
                                           is not allowed for `{frag}` fragments",
                                          name=name,
                                          frag=frag_spec,
                                          next=quoted_tt_to_string(next_token),
-                                         may_be=may_be)
+                                         may_be=may_be),
                             );
+                            err.span_label(
+                                sp,
+                                format!("not allowed after `{}` fragments", frag_spec),
+                            );
+                            let msg = "allowed there are: ";
+                            match &possible[..] {
+                                &[] => {}
+                                &[t] => {
+                                    err.note(&format!(
+                                        "only {} is allowed after `{}` fragments",
+                                        t,
+                                        frag_spec,
+                                    ));
+                                }
+                                ts => {
+                                    err.note(&format!(
+                                        "{}{} or {}",
+                                        msg,
+                                        ts[..ts.len() - 1].iter().map(|s| *s)
+                                            .collect::<Vec<_>>().join(", "),
+                                        ts[ts.len() - 1],
+                                    ));
+                                }
+                            }
+                            err.emit();
                         }
                     }
                 }
@@ -860,6 +886,12 @@ fn frag_can_be_followed_by_any(frag: &str) -> bool {
     }
 }
 
+enum IsInFollow {
+    Yes,
+    No(Vec<&'static str>),
+    Invalid(String, &'static str),
+}
+
 /// True if `frag` can legally be followed by the token `tok`. For
 /// fragments that can consume an unbounded number of tokens, `tok`
 /// must be within a well-defined follow set. This is intended to
@@ -868,81 +900,99 @@ fn frag_can_be_followed_by_any(frag: &str) -> bool {
 /// 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: &str) -> Result<bool, (String, &'static str)> {
+fn is_in_follow(tok: &quoted::TokenTree, frag: &str) -> IsInFollow {
     use self::quoted::TokenTree;
 
     if let TokenTree::Token(_, token::CloseDelim(_)) = *tok {
         // closing a token tree can never be matched by any fragment;
         // iow, we always require that `(` and `)` match, etc.
-        Ok(true)
+        IsInFollow::Yes
     } else {
         match frag {
             "item" => {
                 // since items *must* be followed by either a `;` or a `}`, we can
                 // accept anything after them
-                Ok(true)
+                IsInFollow::Yes
             },
             "block" => {
                 // anything can follow block, the braces provide an easy boundary to
                 // maintain
-                Ok(true)
+                IsInFollow::Yes
             },
-            "stmt" | "expr"  => match *tok {
-                TokenTree::Token(_, ref tok) => match *tok {
-                    FatArrow | Comma | Semi => Ok(true),
-                    _ => Ok(false)
-                },
-                _ => Ok(false),
+            "stmt" | "expr"  => {
+                let tokens = vec!["`=>`", "`,`", "`;`"];
+                match *tok {
+                    TokenTree::Token(_, ref tok) => match *tok {
+                        FatArrow | Comma | Semi => IsInFollow::Yes,
+                        _ => IsInFollow::No(tokens),
+                    },
+                    _ => IsInFollow::No(tokens),
+                }
             },
-            "pat" => match *tok {
-                TokenTree::Token(_, ref tok) => match *tok {
-                    FatArrow | Comma | Eq | BinOp(token::Or) => Ok(true),
-                    Ident(i, false) if i.name == "if" || i.name == "in" => Ok(true),
-                    _ => Ok(false)
-                },
-                _ => Ok(false),
+            "pat" => {
+                let tokens = vec!["`=>`", "`,`", "`=`", "`|`", "`if`", "`in`"];
+                match *tok {
+                    TokenTree::Token(_, ref tok) => match *tok {
+                        FatArrow | Comma | Eq | BinOp(token::Or) => IsInFollow::Yes,
+                        Ident(i, false) if i.name == "if" || i.name == "in" => IsInFollow::Yes,
+                        _ => IsInFollow::No(tokens),
+                    },
+                    _ => IsInFollow::No(tokens),
+                }
             },
-            "path" | "ty" => match *tok {
-                TokenTree::Token(_, ref tok) => match *tok {
-                    OpenDelim(token::DelimToken::Brace) | OpenDelim(token::DelimToken::Bracket) |
-                    Comma | FatArrow | Colon | Eq | Gt | BinOp(token::Shr) | Semi |
-                    BinOp(token::Or) => Ok(true),
-                    Ident(i, false) if i.name == "as" || i.name == "where" => Ok(true),
-                    _ => Ok(false)
-                },
-                TokenTree::MetaVarDecl(_, _, frag) if frag.name == "block" => Ok(true),
-                _ => Ok(false),
+            "path" | "ty" => {
+                let tokens = vec![
+                    "`{`", "`[`", "`=>`", "`,`", "`>`","`=`", "`:`", "`;`", "`|`", "`as`",
+                    "`where`",
+                ];
+                match *tok {
+                    TokenTree::Token(_, ref tok) => match *tok {
+                        OpenDelim(token::DelimToken::Brace) |
+                        OpenDelim(token::DelimToken::Bracket) |
+                        Comma | FatArrow | Colon | Eq | Gt | BinOp(token::Shr) | Semi |
+                        BinOp(token::Or) => IsInFollow::Yes,
+                        Ident(i, false) if i.name == "as" || i.name == "where" => IsInFollow::Yes,
+                        _ => IsInFollow::No(tokens),
+                    },
+                    TokenTree::MetaVarDecl(_, _, frag) if frag.name == "block" => IsInFollow::Yes,
+                    _ => IsInFollow::No(tokens),
+                }
             },
             "ident" | "lifetime" => {
                 // being a single token, idents and lifetimes are harmless
-                Ok(true)
+                IsInFollow::Yes
             },
             "literal" => {
                 // literals may be of a single token, or two tokens (negative numbers)
-                Ok(true)
+                IsInFollow::Yes
             },
             "meta" | "tt" => {
                 // being either a single token or a delimited sequence, tt is
                 // harmless
-                Ok(true)
+                IsInFollow::Yes
             },
             "vis" => {
                 // Explicitly disallow `priv`, on the off chance it comes back.
+                let tokens = vec!["`,`", "an ident", "a type"];
                 match *tok {
                     TokenTree::Token(_, ref tok) => match *tok {
-                        Comma => Ok(true),
-                        Ident(i, is_raw) if is_raw || i.name != "priv" => Ok(true),
-                        ref tok => Ok(tok.can_begin_type())
+                        Comma => IsInFollow::Yes,
+                        Ident(i, is_raw) if is_raw || i.name != "priv" => IsInFollow::Yes,
+                        ref tok => if tok.can_begin_type() {
+                            IsInFollow::Yes
+                        } else {
+                            IsInFollow::No(tokens)
+                        }
                     },
                     TokenTree::MetaVarDecl(_, _, frag) if frag.name == "ident"
                                                        || frag.name == "ty"
-                                                       || frag.name == "path" => Ok(true),
-                    _ => Ok(false)
+                                                       || frag.name == "path" => IsInFollow::Yes,
+                    _ => IsInFollow::No(tokens),
                 }
             },
-            "" => Ok(true), // keywords::Invalid
-            _ => Err((format!("invalid fragment specifier `{}`", frag),
-                     VALID_FRAGMENT_NAMES_MSG))
+            "" => IsInFollow::Yes, // keywords::Invalid
+            _ => IsInFollow::Invalid(format!("invalid fragment specifier `{}`", frag),
+                                     VALID_FRAGMENT_NAMES_MSG),
         }
     }
 }
diff --git a/src/test/ui/macros/macro-follow.stderr b/src/test/ui/macros/macro-follow.stderr
index ccd658af89fbb..8760f6eb572e3 100644
--- a/src/test/ui/macros/macro-follow.stderr
+++ b/src/test/ui/macros/macro-follow.stderr
@@ -2,511 +2,681 @@ error: `$p:pat` is followed by `(`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:17:14
    |
 LL |     ($p:pat ()) => {};       //~ERROR  `$p:pat` is followed by `(`
-   |              ^
+   |              ^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `[`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:18:14
    |
 LL |     ($p:pat []) => {};       //~ERROR  `$p:pat` is followed by `[`
-   |              ^
+   |              ^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `{`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:19:14
    |
 LL |     ($p:pat {}) => {};       //~ERROR  `$p:pat` is followed by `{`
-   |              ^
+   |              ^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `:`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:20:13
    |
 LL |     ($p:pat :) => {};        //~ERROR `$p:pat` is followed by `:`
-   |             ^
+   |             ^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `>`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:21:13
    |
 LL |     ($p:pat >) => {};        //~ERROR `$p:pat` is followed by `>`
-   |             ^
+   |             ^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `+`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:22:13
    |
 LL |     ($p:pat +) => {};        //~ERROR `$p:pat` is followed by `+`
-   |             ^
+   |             ^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `ident`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:23:13
    |
 LL |     ($p:pat ident) => {};    //~ERROR `$p:pat` is followed by `ident`
-   |             ^^^^^
+   |             ^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `$p:pat`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:24:13
    |
 LL |     ($p:pat $p:pat) => {};   //~ERROR `$p:pat` is followed by `$p:pat`
-   |             ^^^^^^
+   |             ^^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `$e:expr`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:25:13
    |
 LL |     ($p:pat $e:expr) => {};  //~ERROR `$p:pat` is followed by `$e:expr`
-   |             ^^^^^^^
+   |             ^^^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `$t:ty`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:26:13
    |
 LL |     ($p:pat $t:ty) => {};    //~ERROR `$p:pat` is followed by `$t:ty`
-   |             ^^^^^
+   |             ^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `$s:stmt`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:27:13
    |
 LL |     ($p:pat $s:stmt) => {};  //~ERROR `$p:pat` is followed by `$s:stmt`
-   |             ^^^^^^^
+   |             ^^^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `$p:path`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:28:13
    |
 LL |     ($p:pat $p:path) => {};  //~ERROR `$p:pat` is followed by `$p:path`
-   |             ^^^^^^^
+   |             ^^^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `$b:block`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:29:13
    |
 LL |     ($p:pat $b:block) => {}; //~ERROR `$p:pat` is followed by `$b:block`
-   |             ^^^^^^^^
+   |             ^^^^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `$i:ident`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:30:13
    |
 LL |     ($p:pat $i:ident) => {}; //~ERROR `$p:pat` is followed by `$i:ident`
-   |             ^^^^^^^^
+   |             ^^^^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `$t:tt`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:31:13
    |
 LL |     ($p:pat $t:tt) => {};    //~ERROR `$p:pat` is followed by `$t:tt`
-   |             ^^^^^
+   |             ^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `$i:item`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:32:13
    |
 LL |     ($p:pat $i:item) => {};  //~ERROR `$p:pat` is followed by `$i:item`
-   |             ^^^^^^^
+   |             ^^^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$p:pat` is followed by `$m:meta`, which is not allowed for `pat` fragments
   --> $DIR/macro-follow.rs:33:13
    |
 LL |     ($p:pat $m:meta) => {};  //~ERROR `$p:pat` is followed by `$m:meta`
-   |             ^^^^^^^
+   |             ^^^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$e:expr` is followed by `(`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:37:15
    |
 LL |     ($e:expr ()) => {};       //~ERROR  `$e:expr` is followed by `(`
-   |               ^
+   |               ^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `[`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:38:15
    |
 LL |     ($e:expr []) => {};       //~ERROR  `$e:expr` is followed by `[`
-   |               ^
+   |               ^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `{`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:39:15
    |
 LL |     ($e:expr {}) => {};       //~ERROR  `$e:expr` is followed by `{`
-   |               ^
+   |               ^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `=`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:40:14
    |
 LL |     ($e:expr =) => {};        //~ERROR `$e:expr` is followed by `=`
-   |              ^
+   |              ^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `|`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:41:14
    |
 LL |     ($e:expr |) => {};        //~ERROR `$e:expr` is followed by `|`
-   |              ^
+   |              ^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `:`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:42:14
    |
 LL |     ($e:expr :) => {};        //~ERROR `$e:expr` is followed by `:`
-   |              ^
+   |              ^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `>`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:43:14
    |
 LL |     ($e:expr >) => {};        //~ERROR `$e:expr` is followed by `>`
-   |              ^
+   |              ^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `+`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:44:14
    |
 LL |     ($e:expr +) => {};        //~ERROR `$e:expr` is followed by `+`
-   |              ^
+   |              ^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `ident`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:45:14
    |
 LL |     ($e:expr ident) => {};    //~ERROR `$e:expr` is followed by `ident`
-   |              ^^^^^
+   |              ^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `if`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:46:14
    |
 LL |     ($e:expr if) => {};       //~ERROR `$e:expr` is followed by `if`
-   |              ^^
+   |              ^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `in`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:47:14
    |
 LL |     ($e:expr in) => {};       //~ERROR `$e:expr` is followed by `in`
-   |              ^^
+   |              ^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `$p:pat`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:48:14
    |
 LL |     ($e:expr $p:pat) => {};   //~ERROR `$e:expr` is followed by `$p:pat`
-   |              ^^^^^^
+   |              ^^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `$e:expr`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:49:14
    |
 LL |     ($e:expr $e:expr) => {};  //~ERROR `$e:expr` is followed by `$e:expr`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `$t:ty`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:50:14
    |
 LL |     ($e:expr $t:ty) => {};    //~ERROR `$e:expr` is followed by `$t:ty`
-   |              ^^^^^
+   |              ^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `$s:stmt`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:51:14
    |
 LL |     ($e:expr $s:stmt) => {};  //~ERROR `$e:expr` is followed by `$s:stmt`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `$p:path`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:52:14
    |
 LL |     ($e:expr $p:path) => {};  //~ERROR `$e:expr` is followed by `$p:path`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `$b:block`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:53:14
    |
 LL |     ($e:expr $b:block) => {}; //~ERROR `$e:expr` is followed by `$b:block`
-   |              ^^^^^^^^
+   |              ^^^^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `$i:ident`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:54:14
    |
 LL |     ($e:expr $i:ident) => {}; //~ERROR `$e:expr` is followed by `$i:ident`
-   |              ^^^^^^^^
+   |              ^^^^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `$t:tt`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:55:14
    |
 LL |     ($e:expr $t:tt) => {};    //~ERROR `$e:expr` is followed by `$t:tt`
-   |              ^^^^^
+   |              ^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `$i:item`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:56:14
    |
 LL |     ($e:expr $i:item) => {};  //~ERROR `$e:expr` is followed by `$i:item`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$e:expr` is followed by `$m:meta`, which is not allowed for `expr` fragments
   --> $DIR/macro-follow.rs:57:14
    |
 LL |     ($e:expr $m:meta) => {};  //~ERROR `$e:expr` is followed by `$m:meta`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$t:ty` is followed by `(`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:62:13
    |
 LL |     ($t:ty ()) => {};       //~ERROR  `$t:ty` is followed by `(`
-   |             ^
+   |             ^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `+`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:64:12
    |
 LL |     ($t:ty +) => {};        //~ERROR `$t:ty` is followed by `+`
-   |            ^
+   |            ^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `ident`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:65:12
    |
 LL |     ($t:ty ident) => {};    //~ERROR `$t:ty` is followed by `ident`
-   |            ^^^^^
+   |            ^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `if`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:66:12
    |
 LL |     ($t:ty if) => {};       //~ERROR `$t:ty` is followed by `if`
-   |            ^^
+   |            ^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `$p:pat`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:67:12
    |
 LL |     ($t:ty $p:pat) => {};   //~ERROR `$t:ty` is followed by `$p:pat`
-   |            ^^^^^^
+   |            ^^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `$e:expr`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:68:12
    |
 LL |     ($t:ty $e:expr) => {};  //~ERROR `$t:ty` is followed by `$e:expr`
-   |            ^^^^^^^
+   |            ^^^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `$t:ty`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:69:12
    |
 LL |     ($t:ty $t:ty) => {};    //~ERROR `$t:ty` is followed by `$t:ty`
-   |            ^^^^^
+   |            ^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `$s:stmt`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:70:12
    |
 LL |     ($t:ty $s:stmt) => {};  //~ERROR `$t:ty` is followed by `$s:stmt`
-   |            ^^^^^^^
+   |            ^^^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `$p:path`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:71:12
    |
 LL |     ($t:ty $p:path) => {};  //~ERROR `$t:ty` is followed by `$p:path`
-   |            ^^^^^^^
+   |            ^^^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `$i:ident`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:73:12
    |
 LL |     ($t:ty $i:ident) => {}; //~ERROR `$t:ty` is followed by `$i:ident`
-   |            ^^^^^^^^
+   |            ^^^^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `$t:tt`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:74:12
    |
 LL |     ($t:ty $t:tt) => {};    //~ERROR `$t:ty` is followed by `$t:tt`
-   |            ^^^^^
+   |            ^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `$i:item`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:75:12
    |
 LL |     ($t:ty $i:item) => {};  //~ERROR `$t:ty` is followed by `$i:item`
-   |            ^^^^^^^
+   |            ^^^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$t:ty` is followed by `$m:meta`, which is not allowed for `ty` fragments
   --> $DIR/macro-follow.rs:76:12
    |
 LL |     ($t:ty $m:meta) => {};  //~ERROR `$t:ty` is followed by `$m:meta`
-   |            ^^^^^^^
+   |            ^^^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$s:stmt` is followed by `(`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:80:15
    |
 LL |     ($s:stmt ()) => {};       //~ERROR  `$s:stmt` is followed by `(`
-   |               ^
+   |               ^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `[`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:81:15
    |
 LL |     ($s:stmt []) => {};       //~ERROR  `$s:stmt` is followed by `[`
-   |               ^
+   |               ^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `{`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:82:15
    |
 LL |     ($s:stmt {}) => {};       //~ERROR  `$s:stmt` is followed by `{`
-   |               ^
+   |               ^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `=`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:83:14
    |
 LL |     ($s:stmt =) => {};        //~ERROR `$s:stmt` is followed by `=`
-   |              ^
+   |              ^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `|`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:84:14
    |
 LL |     ($s:stmt |) => {};        //~ERROR `$s:stmt` is followed by `|`
-   |              ^
+   |              ^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `:`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:85:14
    |
 LL |     ($s:stmt :) => {};        //~ERROR `$s:stmt` is followed by `:`
-   |              ^
+   |              ^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `>`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:86:14
    |
 LL |     ($s:stmt >) => {};        //~ERROR `$s:stmt` is followed by `>`
-   |              ^
+   |              ^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `+`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:87:14
    |
 LL |     ($s:stmt +) => {};        //~ERROR `$s:stmt` is followed by `+`
-   |              ^
+   |              ^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `ident`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:88:14
    |
 LL |     ($s:stmt ident) => {};    //~ERROR `$s:stmt` is followed by `ident`
-   |              ^^^^^
+   |              ^^^^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `if`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:89:14
    |
 LL |     ($s:stmt if) => {};       //~ERROR `$s:stmt` is followed by `if`
-   |              ^^
+   |              ^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `in`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:90:14
    |
 LL |     ($s:stmt in) => {};       //~ERROR `$s:stmt` is followed by `in`
-   |              ^^
+   |              ^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `$p:pat`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:91:14
    |
 LL |     ($s:stmt $p:pat) => {};   //~ERROR `$s:stmt` is followed by `$p:pat`
-   |              ^^^^^^
+   |              ^^^^^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `$e:expr`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:92:14
    |
 LL |     ($s:stmt $e:expr) => {};  //~ERROR `$s:stmt` is followed by `$e:expr`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `$t:ty`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:93:14
    |
 LL |     ($s:stmt $t:ty) => {};    //~ERROR `$s:stmt` is followed by `$t:ty`
-   |              ^^^^^
+   |              ^^^^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `$s:stmt`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:94:14
    |
 LL |     ($s:stmt $s:stmt) => {};  //~ERROR `$s:stmt` is followed by `$s:stmt`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `$p:path`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:95:14
    |
 LL |     ($s:stmt $p:path) => {};  //~ERROR `$s:stmt` is followed by `$p:path`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `$b:block`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:96:14
    |
 LL |     ($s:stmt $b:block) => {}; //~ERROR `$s:stmt` is followed by `$b:block`
-   |              ^^^^^^^^
+   |              ^^^^^^^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `$i:ident`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:97:14
    |
 LL |     ($s:stmt $i:ident) => {}; //~ERROR `$s:stmt` is followed by `$i:ident`
-   |              ^^^^^^^^
+   |              ^^^^^^^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `$t:tt`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:98:14
    |
 LL |     ($s:stmt $t:tt) => {};    //~ERROR `$s:stmt` is followed by `$t:tt`
-   |              ^^^^^
+   |              ^^^^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `$i:item`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:99:14
    |
 LL |     ($s:stmt $i:item) => {};  //~ERROR `$s:stmt` is followed by `$i:item`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$s:stmt` is followed by `$m:meta`, which is not allowed for `stmt` fragments
   --> $DIR/macro-follow.rs:100:14
    |
 LL |     ($s:stmt $m:meta) => {};  //~ERROR `$s:stmt` is followed by `$m:meta`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `stmt` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$p:path` is followed by `(`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:104:15
    |
 LL |     ($p:path ()) => {};       //~ERROR  `$p:path` is followed by `(`
-   |               ^
+   |               ^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `+`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:106:14
    |
 LL |     ($p:path +) => {};        //~ERROR `$p:path` is followed by `+`
-   |              ^
+   |              ^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `ident`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:107:14
    |
 LL |     ($p:path ident) => {};    //~ERROR `$p:path` is followed by `ident`
-   |              ^^^^^
+   |              ^^^^^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `if`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:108:14
    |
 LL |     ($p:path if) => {};       //~ERROR `$p:path` is followed by `if`
-   |              ^^
+   |              ^^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `$p:pat`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:109:14
    |
 LL |     ($p:path $p:pat) => {};   //~ERROR `$p:path` is followed by `$p:pat`
-   |              ^^^^^^
+   |              ^^^^^^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `$e:expr`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:110:14
    |
 LL |     ($p:path $e:expr) => {};  //~ERROR `$p:path` is followed by `$e:expr`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `$t:ty`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:111:14
    |
 LL |     ($p:path $t:ty) => {};    //~ERROR `$p:path` is followed by `$t:ty`
-   |              ^^^^^
+   |              ^^^^^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `$s:stmt`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:112:14
    |
 LL |     ($p:path $s:stmt) => {};  //~ERROR `$p:path` is followed by `$s:stmt`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `$p:path`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:113:14
    |
 LL |     ($p:path $p:path) => {};  //~ERROR `$p:path` is followed by `$p:path`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `$i:ident`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:115:14
    |
 LL |     ($p:path $i:ident) => {}; //~ERROR `$p:path` is followed by `$i:ident`
-   |              ^^^^^^^^
+   |              ^^^^^^^^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `$t:tt`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:116:14
    |
 LL |     ($p:path $t:tt) => {};    //~ERROR `$p:path` is followed by `$t:tt`
-   |              ^^^^^
+   |              ^^^^^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `$i:item`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:117:14
    |
 LL |     ($p:path $i:item) => {};  //~ERROR `$p:path` is followed by `$i:item`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$p:path` is followed by `$m:meta`, which is not allowed for `path` fragments
   --> $DIR/macro-follow.rs:118:14
    |
 LL |     ($p:path $m:meta) => {};  //~ERROR `$p:path` is followed by `$m:meta`
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `path` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: aborting due to 85 previous errors
 
diff --git a/src/test/ui/macros/macro-followed-by-seq-bad.stderr b/src/test/ui/macros/macro-followed-by-seq-bad.stderr
index bb070334d36e9..2ad8990e1156f 100644
--- a/src/test/ui/macros/macro-followed-by-seq-bad.stderr
+++ b/src/test/ui/macros/macro-followed-by-seq-bad.stderr
@@ -2,13 +2,17 @@ error: `$a:expr` is followed by `$b:tt`, which is not allowed for `expr` fragmen
   --> $DIR/macro-followed-by-seq-bad.rs:17:15
    |
 LL |   ( $a:expr $($b:tt)* ) => { }; //~ ERROR not allowed for `expr` fragments
-   |               ^^^^^
+   |               ^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: `$a:ty` is followed by `$b:tt`, which is not allowed for `ty` fragments
   --> $DIR/macro-followed-by-seq-bad.rs:18:13
    |
 LL |   ( $a:ty $($b:tt)* ) => { };   //~ ERROR not allowed for `ty` fragments
-   |             ^^^^^
+   |             ^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/macros/macro-input-future-proofing.stderr b/src/test/ui/macros/macro-input-future-proofing.stderr
index aed7a8a119ced..4bb46e39562cb 100644
--- a/src/test/ui/macros/macro-input-future-proofing.stderr
+++ b/src/test/ui/macros/macro-input-future-proofing.stderr
@@ -2,55 +2,73 @@ error: `$ty:ty` is followed by `<`, which is not allowed for `ty` fragments
   --> $DIR/macro-input-future-proofing.rs:14:13
    |
 LL |     ($ty:ty <) => (); //~ ERROR `$ty:ty` is followed by `<`, which is not allowed for `ty`
-   |             ^
+   |             ^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$ty:ty` is followed by `<`, which is not allowed for `ty` fragments
   --> $DIR/macro-input-future-proofing.rs:15:13
    |
 LL |     ($ty:ty < foo ,) => (); //~ ERROR `$ty:ty` is followed by `<`, which is not allowed for `ty`
-   |             ^
+   |             ^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$pa:pat` is followed by `>`, which is not allowed for `pat` fragments
   --> $DIR/macro-input-future-proofing.rs:21:14
    |
 LL |     ($pa:pat >) => (); //~ ERROR `$pa:pat` is followed by `>`, which is not allowed for `pat`
-   |              ^
+   |              ^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$pa:pat` is followed by `$pb:pat`, which is not allowed for `pat` fragments
   --> $DIR/macro-input-future-proofing.rs:23:14
    |
 LL |     ($pa:pat $pb:pat $ty:ty ,) => ();
-   |              ^^^^^^^
+   |              ^^^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$pb:pat` is followed by `$ty:ty`, which is not allowed for `pat` fragments
   --> $DIR/macro-input-future-proofing.rs:23:22
    |
 LL |     ($pa:pat $pb:pat $ty:ty ,) => ();
-   |                      ^^^^^^
+   |                      ^^^^^^ not allowed after `pat` fragments
+   |
+   = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
 
 error: `$ty:ty` is followed by `-`, which is not allowed for `ty` fragments
   --> $DIR/macro-input-future-proofing.rs:26:17
    |
 LL |     ($($ty:ty)* -) => (); //~ ERROR `$ty:ty` is followed by `-`
-   |                 ^
+   |                 ^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$b:ty` is followed by `-`, which is not allowed for `ty` fragments
   --> $DIR/macro-input-future-proofing.rs:27:23
    |
 LL |     ($($a:ty, $b:ty)* -) => (); //~ ERROR `$b:ty` is followed by `-`
-   |                       ^
+   |                       ^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$ty:ty` is followed by `-`, which is not allowed for `ty` fragments
   --> $DIR/macro-input-future-proofing.rs:28:7
    |
 LL |     ($($ty:ty)-+) => (); //~ ERROR `$ty:ty` is followed by `-`, which is not allowed for `ty`
-   |       ^^^^^^^^
+   |       ^^^^^^^^ not allowed after `ty` fragments
+   |
+   = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
 
 error: `$a:expr` is followed by `$b:tt`, which is not allowed for `expr` fragments
   --> $DIR/macro-input-future-proofing.rs:29:21
    |
 LL |     ( $($a:expr)* $($b:tt)* ) => { };
-   |                     ^^^^^
+   |                     ^^^^^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: aborting due to 9 previous errors
 
diff --git a/src/test/ui/unused/unused-macro-with-follow-violation.stderr b/src/test/ui/unused/unused-macro-with-follow-violation.stderr
index 8efb191c7c645..78362fcb05a8c 100644
--- a/src/test/ui/unused/unused-macro-with-follow-violation.stderr
+++ b/src/test/ui/unused/unused-macro-with-follow-violation.stderr
@@ -2,7 +2,9 @@ error: `$e:expr` is followed by `+`, which is not allowed for `expr` fragments
   --> $DIR/unused-macro-with-follow-violation.rs:14:14
    |
 LL |     ($e:expr +) => () //~ ERROR not allowed for `expr` fragments
-   |              ^
+   |              ^ not allowed after `expr` fragments
+   |
+   = note: allowed there are: `=>`, `,` or `;`
 
 error: aborting due to previous error
 

From ee7f4a27d324db13ce27df9d79f258e64086d8f1 Mon Sep 17 00:00:00 2001
From: Oliver Scherer <github35764891676564198441@oli-obk.de>
Date: Thu, 25 Oct 2018 21:14:25 +0200
Subject: [PATCH 45/48] Grammar nit

---
 src/librustc_mir/transform/promote_consts.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/librustc_mir/transform/promote_consts.rs b/src/librustc_mir/transform/promote_consts.rs
index 1d45850a080d5..a27809ca1f2ec 100644
--- a/src/librustc_mir/transform/promote_consts.rs
+++ b/src/librustc_mir/transform/promote_consts.rs
@@ -333,8 +333,8 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                             mem::replace(&mut args[index], operand)
                         }
                         // We expected a `TerminatorKind::Call` for which we'd like to promote an
-                        // argument. Since `qualify_consts` saw a `TerminatorKind::Call` here, but
-                        // we are seeing a `Goto`, that means that the `promote_temps` method
+                        // argument. `qualify_consts` saw a `TerminatorKind::Call` here, but
+                        // we are seeing a `Goto`. That means that the `promote_temps` method
                         // already promoted this call away entirely. This case occurs when calling
                         // a function requiring a constant argument and as that constant value
                         // providing a value whose computation contains another call to a function

From fd77500ed1d12dfdffff95e65530c2806a324f22 Mon Sep 17 00:00:00 2001
From: Oliver Scherer <github35764891676564198441@oli-obk.de>
Date: Thu, 25 Oct 2018 21:18:22 +0200
Subject: [PATCH 46/48] Clear up nonpromotable const fn call qualification

---
 src/librustc_mir/transform/qualify_consts.rs | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs
index 1305d02a87b6a..e7d694ffba91c 100644
--- a/src/librustc_mir/transform/qualify_consts.rs
+++ b/src/librustc_mir/transform/qualify_consts.rs
@@ -1000,11 +1000,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
             }
 
             // non-const fn calls.
-            if is_const_fn {
-                if !is_promotable_const_fn && self.mode == Mode::Fn {
-                    self.qualif = Qualif::NOT_PROMOTABLE;
-                }
-            } else {
+            if !is_const_fn {
                 self.qualif = Qualif::NOT_CONST;
                 if self.mode != Mode::Fn {
                     self.tcx.sess.delay_span_bug(
@@ -1022,6 +1018,11 @@ impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> {
                     // Be conservative about the returned value of a const fn.
                     let tcx = self.tcx;
                     let ty = dest.ty(self.mir, tcx).to_ty(tcx);
+                    if is_const_fn && !is_promotable_const_fn && self.mode == Mode::Fn {
+                        self.qualif = Qualif::NOT_PROMOTABLE;
+                    } else {
+                        self.qualif = Qualif::empty();
+                    }
                     self.add_type(ty);
                 }
                 self.assign(dest, location);

From 38d9277a77e982e49df07725b62b21c423b6428e Mon Sep 17 00:00:00 2001
From: Nicholas Nethercote <nnethercote@mozilla.com>
Date: Thu, 25 Oct 2018 20:17:39 +1100
Subject: [PATCH 47/48] Shrink `Statement`.

This commit reduces the size of `Statement` from 80 bytes to 56 bytes on
64-bit platforms, by boxing the `AscribeUserType` variant of
`StatementKind`.

This change reduces instruction counts on most benchmarks by 1--3%.
---
 src/librustc/mir/mod.rs                             | 6 +++++-
 src/librustc_mir/borrow_check/nll/type_check/mod.rs | 2 +-
 src/librustc_mir/build/expr/as_place.rs             | 4 ++--
 src/librustc_mir/build/matches/mod.rs               | 4 ++--
 4 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/librustc/mir/mod.rs b/src/librustc/mir/mod.rs
index 62b5327ae4692..8966af728919a 100644
--- a/src/librustc/mir/mod.rs
+++ b/src/librustc/mir/mod.rs
@@ -1674,6 +1674,10 @@ impl<'tcx> Statement<'tcx> {
     /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
     /// invalidating statement indices in `Location`s.
     pub fn make_nop(&mut self) {
+        // `Statement` contributes significantly to peak memory usage. Make
+        // sure it doesn't get bigger.
+        static_assert!(STATEMENT_IS_AT_MOST_56_BYTES: mem::size_of::<Statement<'_>>() <= 56);
+
         self.kind = StatementKind::Nop
     }
 
@@ -1737,7 +1741,7 @@ pub enum StatementKind<'tcx> {
     /// - `Contravariant` -- requires that `T_y :> T`
     /// - `Invariant` -- requires that `T_y == T`
     /// - `Bivariant` -- no effect
-    AscribeUserType(Place<'tcx>, ty::Variance, UserTypeAnnotation<'tcx>),
+    AscribeUserType(Place<'tcx>, ty::Variance, Box<UserTypeAnnotation<'tcx>>),
 
     /// No-op. Useful for deleting instructions without affecting statement indices.
     Nop,
diff --git a/src/librustc_mir/borrow_check/nll/type_check/mod.rs b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
index 6db107344747e..befa5880e7faf 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
@@ -1308,7 +1308,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
                     );
                 };
             }
-            StatementKind::AscribeUserType(ref place, variance, c_ty) => {
+            StatementKind::AscribeUserType(ref place, variance, box c_ty) => {
                 let place_ty = place.ty(mir, tcx).to_ty(tcx);
                 if let Err(terr) = self.relate_type_and_user_type(
                     place_ty,
diff --git a/src/librustc_mir/build/expr/as_place.rs b/src/librustc_mir/build/expr/as_place.rs
index 820822b7f5bbd..8d6b6bb5c74f1 100644
--- a/src/librustc_mir/build/expr/as_place.rs
+++ b/src/librustc_mir/build/expr/as_place.rs
@@ -147,7 +147,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                             kind: StatementKind::AscribeUserType(
                                 place.clone(),
                                 Variance::Invariant,
-                                user_ty,
+                                box user_ty,
                             ),
                         },
                     );
@@ -167,7 +167,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                             kind: StatementKind::AscribeUserType(
                                 Place::Local(temp.clone()),
                                 Variance::Invariant,
-                                user_ty,
+                                box user_ty,
                             ),
                         },
                     );
diff --git a/src/librustc_mir/build/matches/mod.rs b/src/librustc_mir/build/matches/mod.rs
index a864b39e15791..caacc9311c66b 100644
--- a/src/librustc_mir/build/matches/mod.rs
+++ b/src/librustc_mir/build/matches/mod.rs
@@ -316,7 +316,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                         kind: StatementKind::AscribeUserType(
                             place.clone(),
                             ty::Variance::Invariant,
-                            ascription_user_ty,
+                            box ascription_user_ty,
                         ),
                     },
                 );
@@ -1323,7 +1323,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     kind: StatementKind::AscribeUserType(
                         ascription.source.clone(),
                         ty::Variance::Covariant,
-                        ascription.user_ty,
+                        box ascription.user_ty,
                     ),
                 },
             );

From 3878d24ef6922c133539fe67e0c907166f6261cb Mon Sep 17 00:00:00 2001
From: Shotaro Yamada <sinkuu@sinkuu.xyz>
Date: Fri, 26 Oct 2018 03:11:11 +0900
Subject: [PATCH 48/48] Remove redundant clone

---
 src/bootstrap/dist.rs                            |  4 ++--
 src/bootstrap/test.rs                            |  2 +-
 src/librustc/infer/outlives/obligations.rs       |  2 +-
 src/librustc/infer/region_constraints/mod.rs     |  4 ++--
 src/librustc/traits/error_reporting.rs           |  4 ++--
 src/librustc/traits/project.rs                   |  2 +-
 src/librustc/ty/context.rs                       |  2 +-
 src/librustc_borrowck/borrowck/mod.rs            |  2 +-
 src/librustc_borrowck/borrowck/move_data.rs      |  6 +++---
 src/librustc_codegen_llvm/base.rs                |  2 +-
 src/librustc_codegen_utils/link.rs               |  2 +-
 src/librustc_mir/borrow_check/error_reporting.rs |  2 +-
 src/librustc_mir/build/matches/mod.rs            |  4 ++--
 src/librustc_mir/build/matches/test.rs           |  2 +-
 src/librustc_mir/build/mod.rs                    |  4 ++--
 src/librustc_mir/shim.rs                         |  2 +-
 src/librustc_mir/util/elaborate_drops.rs         |  4 ++--
 src/librustc_resolve/build_reduced_graph.rs      |  2 +-
 src/librustc_save_analysis/dump_visitor.rs       |  2 +-
 src/librustc_target/spec/mod.rs                  |  8 ++++----
 src/librustc_typeck/check/autoderef.rs           |  2 +-
 src/librustc_typeck/check/compare_method.rs      |  2 +-
 src/librustc_typeck/check/method/probe.rs        |  4 ++--
 src/librustc_typeck/check/mod.rs                 | 16 ++++------------
 src/librustdoc/clean/auto_trait.rs               |  2 +-
 src/librustdoc/clean/blanket_impl.rs             |  4 ++--
 src/librustdoc/clean/mod.rs                      |  2 +-
 src/librustdoc/html/render.rs                    |  8 ++++----
 src/librustdoc/lib.rs                            |  2 +-
 src/librustdoc/test.rs                           |  4 ++--
 src/libsyntax/ext/tt/macro_rules.rs              |  3 +--
 src/libsyntax/ext/tt/transcribe.rs               |  4 ++--
 src/libsyntax/test.rs                            |  2 +-
 src/libsyntax_ext/deriving/cmp/partial_ord.rs    |  2 +-
 src/libsyntax_ext/deriving/custom.rs             |  2 +-
 35 files changed, 56 insertions(+), 65 deletions(-)

diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index 4de899ee2d599..fea6302d0a119 100644
--- a/src/bootstrap/dist.rs
+++ b/src/bootstrap/dist.rs
@@ -1447,8 +1447,8 @@ impl Step for Extended {
         tarballs.extend(rls_installer.clone());
         tarballs.extend(clippy_installer.clone());
         tarballs.extend(rustfmt_installer.clone());
-        tarballs.extend(llvm_tools_installer.clone());
-        tarballs.extend(lldb_installer.clone());
+        tarballs.extend(llvm_tools_installer);
+        tarballs.extend(lldb_installer);
         tarballs.push(analysis_installer);
         tarballs.push(std_installer);
         if builder.config.docs {
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index fe04a91011ee5..f6032eb9931f7 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -1052,7 +1052,7 @@ impl Step for Compiletest {
         let hostflags = flags.clone();
         cmd.arg("--host-rustcflags").arg(hostflags.join(" "));
 
-        let mut targetflags = flags.clone();
+        let mut targetflags = flags;
         targetflags.push(format!(
             "-Lnative={}",
             builder.test_helpers_out(target).display()
diff --git a/src/librustc/infer/outlives/obligations.rs b/src/librustc/infer/outlives/obligations.rs
index 332859d4f81db..5db850f1588b6 100644
--- a/src/librustc/infer/outlives/obligations.rs
+++ b/src/librustc/infer/outlives/obligations.rs
@@ -458,7 +458,7 @@ where
             );
             debug!("projection_must_outlive: unique declared bound appears in trait ref");
             self.delegate
-                .push_sub_region_constraint(origin.clone(), region, unique_bound);
+                .push_sub_region_constraint(origin, region, unique_bound);
             return;
         }
 
diff --git a/src/librustc/infer/region_constraints/mod.rs b/src/librustc/infer/region_constraints/mod.rs
index 96278e5140c8a..c82603bf56057 100644
--- a/src/librustc/infer/region_constraints/mod.rs
+++ b/src/librustc/infer/region_constraints/mod.rs
@@ -749,7 +749,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
                 a // LUB(a,a) = a
             }
 
-            _ => self.combine_vars(tcx, Lub, a, b, origin.clone()),
+            _ => self.combine_vars(tcx, Lub, a, b, origin),
         }
     }
 
@@ -771,7 +771,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
                 a // GLB(a,a) = a
             }
 
-            _ => self.combine_vars(tcx, Glb, a, b, origin.clone()),
+            _ => self.combine_vars(tcx, Glb, a, b, origin),
         }
     }
 
diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs
index ea30752a820ee..b6df8ebe909f5 100644
--- a/src/librustc/traits/error_reporting.rs
+++ b/src/librustc/traits/error_reporting.rs
@@ -239,7 +239,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
 
             let msg = format!("type mismatch resolving `{}`", predicate);
             let error_id = (DiagnosticMessageId::ErrorId(271),
-                            Some(obligation.cause.span), msg.clone());
+                            Some(obligation.cause.span), msg);
             let fresh = self.tcx.sess.one_time_diagnostics.borrow_mut().insert(error_id);
             if fresh {
                 let mut diag = struct_span_err!(
@@ -379,7 +379,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             }
         }
         if let Some(t) = self.get_parent_trait_ref(&obligation.cause.code) {
-            flags.push(("parent_trait".to_owned(), Some(t.to_string())));
+            flags.push(("parent_trait".to_owned(), Some(t)));
         }
 
         if let Some(k) = obligation.cause.span.compiler_desugaring_kind() {
diff --git a/src/librustc/traits/project.rs b/src/librustc/traits/project.rs
index b266fbe0d1145..4eda47d31ebb5 100644
--- a/src/librustc/traits/project.rs
+++ b/src/librustc/traits/project.rs
@@ -594,7 +594,7 @@ fn opt_normalize_projection_type<'a, 'b, 'gcx, 'tcx>(
 
             // But for now, let's classify this as an overflow:
             let recursion_limit = *selcx.tcx().sess.recursion_limit.get();
-            let obligation = Obligation::with_depth(cause.clone(),
+            let obligation = Obligation::with_depth(cause,
                                                     recursion_limit,
                                                     param_env,
                                                     projection_ty);
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index 1a9f86306325f..1686e3e0e0c09 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -1200,7 +1200,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
             cstore,
             global_arenas: &arenas.global,
             global_interners: interners,
-            dep_graph: dep_graph.clone(),
+            dep_graph,
             types: common_types,
             trait_map,
             export_map: resolutions.export_map.into_iter().map(|(k, v)| {
diff --git a/src/librustc_borrowck/borrowck/mod.rs b/src/librustc_borrowck/borrowck/mod.rs
index da5c5f47c08ac..bf8d02313035c 100644
--- a/src/librustc_borrowck/borrowck/mod.rs
+++ b/src/librustc_borrowck/borrowck/mod.rs
@@ -695,7 +695,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> {
                 let mut err = self.cannot_act_on_moved_value(use_span,
                                                              verb,
                                                              msg,
-                                                             Some(nl.to_string()),
+                                                             Some(nl),
                                                              Origin::Ast);
                 let need_note = match lp.ty.sty {
                     ty::Closure(id, _) => {
diff --git a/src/librustc_borrowck/borrowck/move_data.rs b/src/librustc_borrowck/borrowck/move_data.rs
index d9f223daf6091..8aa2e4641d4f9 100644
--- a/src/librustc_borrowck/borrowck/move_data.rs
+++ b/src/librustc_borrowck/borrowck/move_data.rs
@@ -347,7 +347,7 @@ impl<'a, 'tcx> MoveData<'tcx> {
             lp = base_lp.clone();
         }
 
-        self.add_move_helper(tcx, orig_lp.clone(), id, kind);
+        self.add_move_helper(tcx, orig_lp, id, kind);
     }
 
     fn add_move_helper(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -359,7 +359,7 @@ impl<'a, 'tcx> MoveData<'tcx> {
                id,
                kind);
 
-        let path_index = self.move_path(tcx, lp.clone());
+        let path_index = self.move_path(tcx, lp);
         let move_index = MoveIndex(self.moves.borrow().len());
 
         let next_move = self.path_first_move(path_index);
@@ -402,7 +402,7 @@ impl<'a, 'tcx> MoveData<'tcx> {
             }
         }
 
-        self.add_assignment_helper(tcx, lp.clone(), assign_id, span);
+        self.add_assignment_helper(tcx, lp, assign_id, span);
     }
 
     fn add_assignment_helper(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>,
diff --git a/src/librustc_codegen_llvm/base.rs b/src/librustc_codegen_llvm/base.rs
index 614a562846e86..a9119d49e8b20 100644
--- a/src/librustc_codegen_llvm/base.rs
+++ b/src/librustc_codegen_llvm/base.rs
@@ -784,7 +784,7 @@ pub fn codegen_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
        !tcx.sess.opts.output_types.should_codegen() {
         let ongoing_codegen = write::start_async_codegen(
             tcx,
-            time_graph.clone(),
+            time_graph,
             metadata,
             rx,
             1);
diff --git a/src/librustc_codegen_utils/link.rs b/src/librustc_codegen_utils/link.rs
index 2a1fbe6ace541..66e98793f420d 100644
--- a/src/librustc_codegen_utils/link.rs
+++ b/src/librustc_codegen_utils/link.rs
@@ -138,7 +138,7 @@ pub fn filename_for_input(sess: &Session,
             let suffix = &sess.target.target.options.exe_suffix;
             let out_filename = outputs.path(OutputType::Exe);
             if suffix.is_empty() {
-                out_filename.to_path_buf()
+                out_filename
             } else {
                 out_filename.with_extension(&suffix[1..])
             }
diff --git a/src/librustc_mir/borrow_check/error_reporting.rs b/src/librustc_mir/borrow_check/error_reporting.rs
index b6bb130d3e27f..b2b92a6f85784 100644
--- a/src/librustc_mir/borrow_check/error_reporting.rs
+++ b/src/librustc_mir/borrow_check/error_reporting.rs
@@ -1615,7 +1615,7 @@ impl<'cx, 'gcx, 'tcx> MirBorrowckCtxt<'cx, 'gcx, 'tcx> {
                 ProjectionElem::Index(..)
                 | ProjectionElem::ConstantIndex { .. }
                 | ProjectionElem::Subslice { .. } => {
-                    self.describe_field(&proj.base, field).to_string()
+                    self.describe_field(&proj.base, field)
                 }
             },
         }
diff --git a/src/librustc_mir/build/matches/mod.rs b/src/librustc_mir/build/matches/mod.rs
index a864b39e15791..23a70be66c020 100644
--- a/src/librustc_mir/build/matches/mod.rs
+++ b/src/librustc_mir/build/matches/mod.rs
@@ -265,7 +265,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     block,
                     Statement {
                         source_info,
-                        kind: StatementKind::FakeRead(FakeReadCause::ForLet, place.clone()),
+                        kind: StatementKind::FakeRead(FakeReadCause::ForLet, place),
                     },
                 );
 
@@ -314,7 +314,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     Statement {
                         source_info: ty_source_info,
                         kind: StatementKind::AscribeUserType(
-                            place.clone(),
+                            place,
                             ty::Variance::Invariant,
                             ascription_user_ty,
                         ),
diff --git a/src/librustc_mir/build/matches/test.rs b/src/librustc_mir/build/matches/test.rs
index c7da9c4fbd792..9e6f32909bdea 100644
--- a/src/librustc_mir/build/matches/test.rs
+++ b/src/librustc_mir/build/matches/test.rs
@@ -324,7 +324,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     let ref_ty = self.hir.tcx().mk_ref(region, tam);
 
                     // let lhs_ref_place = &lhs;
-                    let ref_rvalue = Rvalue::Ref(region, BorrowKind::Shared, place.clone());
+                    let ref_rvalue = Rvalue::Ref(region, BorrowKind::Shared, place);
                     let lhs_ref_place = self.temp(ref_ty, test.span);
                     self.cfg.push_assign(block, source_info, &lhs_ref_place, ref_rvalue);
                     let val = Operand::Move(lhs_ref_place);
diff --git a/src/librustc_mir/build/mod.rs b/src/librustc_mir/build/mod.rs
index e6dd0107e9198..6ea4628de24e9 100644
--- a/src/librustc_mir/build/mod.rs
+++ b/src/librustc_mir/build/mod.rs
@@ -644,7 +644,7 @@ fn construct_fn<'a, 'gcx, 'tcx, A>(hir: Cx<'a, 'gcx, 'tcx>,
         }).collect()
     });
 
-    let mut builder = Builder::new(hir.clone(),
+    let mut builder = Builder::new(hir,
         span,
         arguments.len(),
         safety,
@@ -714,7 +714,7 @@ fn construct_const<'a, 'gcx, 'tcx>(
     let ty = hir.tables().expr_ty_adjusted(ast_expr);
     let owner_id = tcx.hir.body_owner(body_id);
     let span = tcx.hir.span(owner_id);
-    let mut builder = Builder::new(hir.clone(), span, 0, Safety::Safe, ty, ty_span,vec![]);
+    let mut builder = Builder::new(hir, span, 0, Safety::Safe, ty, ty_span,vec![]);
 
     let mut block = START_BLOCK;
     let expr = builder.hir.mirror(ast_expr);
diff --git a/src/librustc_mir/shim.rs b/src/librustc_mir/shim.rs
index 4b26094b9fc28..d8f627fcf4dd7 100644
--- a/src/librustc_mir/shim.rs
+++ b/src/librustc_mir/shim.rs
@@ -547,7 +547,7 @@ impl<'a, 'tcx> CloneShimBuilder<'a, 'tcx> {
         // `dest[i] = Clone::clone(src[beg])`;
         // Goto #3 if ok, #5 if unwinding happens.
         let dest_field = dest.clone().index(beg);
-        let src_field = src.clone().index(beg);
+        let src_field = src.index(beg);
         self.make_clone_call(dest_field, src_field, ty, BasicBlock::new(3),
                              BasicBlock::new(5));
 
diff --git a/src/librustc_mir/util/elaborate_drops.rs b/src/librustc_mir/util/elaborate_drops.rs
index 1dca367ffdf5f..d9a1e4a0fd639 100644
--- a/src/librustc_mir/util/elaborate_drops.rs
+++ b/src/librustc_mir/util/elaborate_drops.rs
@@ -753,11 +753,11 @@ impl<'l, 'b, 'tcx, D> DropCtxt<'l, 'b, 'tcx, D>
                 self.place.clone()
             )));
             drop_block_stmts.push(self.assign(&cur, Rvalue::Cast(
-                CastKind::Misc, Operand::Move(tmp.clone()), iter_ty
+                CastKind::Misc, Operand::Move(tmp), iter_ty
             )));
             drop_block_stmts.push(self.assign(&length_or_end,
                 Rvalue::BinaryOp(BinOp::Offset,
-                     Operand::Copy(cur.clone()), Operand::Move(length.clone())
+                     Operand::Copy(cur), Operand::Move(length)
             )));
         } else {
             // index = 0 (length already pushed)
diff --git a/src/librustc_resolve/build_reduced_graph.rs b/src/librustc_resolve/build_reduced_graph.rs
index b7ed3ef59b4c8..a43a3c6ac5a60 100644
--- a/src/librustc_resolve/build_reduced_graph.rs
+++ b/src/librustc_resolve/build_reduced_graph.rs
@@ -218,7 +218,7 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
                 };
                 this.add_import_directive(
                     base.into_iter().collect(),
-                    subclass.clone(),
+                    subclass,
                     source.ident.span,
                     id,
                     root_use_tree.span,
diff --git a/src/librustc_save_analysis/dump_visitor.rs b/src/librustc_save_analysis/dump_visitor.rs
index a7fe1bb421c37..c0b718e4863fc 100644
--- a/src/librustc_save_analysis/dump_visitor.rs
+++ b/src/librustc_save_analysis/dump_visitor.rs
@@ -105,7 +105,7 @@ impl<'l, 'tcx: 'l, 'll, O: DumpOutput + 'll> DumpVisitor<'l, 'tcx, 'll, O> {
             tcx: save_ctxt.tcx,
             save_ctxt,
             dumper,
-            span: span_utils.clone(),
+            span: span_utils,
             cur_scope: CRATE_NODE_ID,
             // mac_defs: FxHashSet::default(),
             macro_calls: FxHashSet::default(),
diff --git a/src/librustc_target/spec/mod.rs b/src/librustc_target/spec/mod.rs
index 9ee4582fabf7b..d43d45f64a55c 100644
--- a/src/librustc_target/spec/mod.rs
+++ b/src/librustc_target/spec/mod.rs
@@ -1132,7 +1132,7 @@ impl ToJson for Target {
         macro_rules! target_val {
             ($attr:ident) => ( {
                 let name = (stringify!($attr)).replace("_", "-");
-                d.insert(name.to_string(), self.$attr.to_json());
+                d.insert(name, self.$attr.to_json());
             } );
             ($attr:ident, $key_name:expr) => ( {
                 let name = $key_name;
@@ -1144,7 +1144,7 @@ impl ToJson for Target {
             ($attr:ident) => ( {
                 let name = (stringify!($attr)).replace("_", "-");
                 if default.$attr != self.options.$attr {
-                    d.insert(name.to_string(), self.options.$attr.to_json());
+                    d.insert(name, self.options.$attr.to_json());
                 }
             } );
             ($attr:ident, $key_name:expr) => ( {
@@ -1160,7 +1160,7 @@ impl ToJson for Target {
                         .iter()
                         .map(|(k, v)| (k.desc().to_owned(), v.clone()))
                         .collect::<BTreeMap<_, _>>();
-                    d.insert(name.to_string(), obj.to_json());
+                    d.insert(name, obj.to_json());
                 }
             } );
             (env - $attr:ident) => ( {
@@ -1170,7 +1170,7 @@ impl ToJson for Target {
                         .iter()
                         .map(|&(ref k, ref v)| k.clone() + "=" + &v)
                         .collect::<Vec<_>>();
-                    d.insert(name.to_string(), obj.to_json());
+                    d.insert(name, obj.to_json());
                 }
             } );
 
diff --git a/src/librustc_typeck/check/autoderef.rs b/src/librustc_typeck/check/autoderef.rs
index 743a2390ec43d..73489309d0742 100644
--- a/src/librustc_typeck/check/autoderef.rs
+++ b/src/librustc_typeck/check/autoderef.rs
@@ -61,7 +61,7 @@ impl<'a, 'gcx, 'tcx> Iterator for Autoderef<'a, 'gcx, 'tcx> {
             let suggested_limit = *tcx.sess.recursion_limit.get() * 2;
             let msg = format!("reached the recursion limit while auto-dereferencing {:?}",
                               self.cur_ty);
-            let error_id = (DiagnosticMessageId::ErrorId(55), Some(self.span), msg.clone());
+            let error_id = (DiagnosticMessageId::ErrorId(55), Some(self.span), msg);
             let fresh = tcx.sess.one_time_diagnostics.borrow_mut().insert(error_id);
             if fresh {
                 struct_span_err!(tcx.sess,
diff --git a/src/librustc_typeck/check/compare_method.rs b/src/librustc_typeck/check/compare_method.rs
index 695812faafff1..54c6c8f7b9322 100644
--- a/src/librustc_typeck/check/compare_method.rs
+++ b/src/librustc_typeck/check/compare_method.rs
@@ -325,7 +325,7 @@ fn compare_predicate_entailment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
                         diag.span_suggestion_with_applicability(
                             impl_err_span,
                             "consider change the type to match the mutability in trait",
-                            trait_err_str.to_string(),
+                            trait_err_str,
                             Applicability::MachineApplicable,
                         );
                     }
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index f4538dbd25e2f..c506f23078f25 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -1157,7 +1157,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
 
                     // Convert the bounds into obligations.
                     let impl_obligations = traits::predicates_for_generics(
-                        cause.clone(), self.param_env, &impl_bounds);
+                        cause, self.param_env, &impl_bounds);
 
                     debug!("impl_obligations={:?}", impl_obligations);
                     impl_obligations.into_iter()
@@ -1175,7 +1175,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
                 TraitCandidate(trait_ref) => {
                     let predicate = trait_ref.to_predicate();
                     let obligation =
-                        traits::Obligation::new(cause.clone(), self.param_env, predicate);
+                        traits::Obligation::new(cause, self.param_env, predicate);
                     if !self.predicate_may_hold(&obligation) {
                         if self.probe(|_| self.select_trait_candidate(trait_ref).is_err()) {
                             // This candidate's primary obligation doesn't even
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 77151351d08a1..85c69d50a1249 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -4752,25 +4752,17 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
         } else if !self.check_for_cast(err, expr, found, expected) {
             let methods = self.get_conversion_methods(expr.span, expected, found);
             if let Ok(expr_text) = self.sess().source_map().span_to_snippet(expr.span) {
-                let suggestions = iter::repeat(expr_text).zip(methods.iter())
+                let suggestions = iter::repeat(&expr_text).zip(methods.iter())
                     .filter_map(|(receiver, method)| {
                         let method_call = format!(".{}()", method.ident);
                         if receiver.ends_with(&method_call) {
                             None  // do not suggest code that is already there (#53348)
                         } else {
-                            /*
-                            methods defined in `method_call_list` will overwrite
-                            `.clone()` in copy of `receiver`
-                            */
                             let method_call_list = [".to_vec()", ".to_string()"];
                             if receiver.ends_with(".clone()")
-                                    && method_call_list.contains(&method_call.as_str()){
-                                // created copy of `receiver` because we don't want other
-                                // suggestion to get affected
-                                let mut new_receiver = receiver.clone();
-                                let max_len = new_receiver.rfind(".").unwrap();
-                                new_receiver.truncate(max_len);
-                                Some(format!("{}{}", new_receiver, method_call))
+                                    && method_call_list.contains(&method_call.as_str()) {
+                                let max_len = receiver.rfind(".").unwrap();
+                                Some(format!("{}{}", &receiver[..max_len], method_call))
                             }
                             else {
                                 Some(format!("{}{}", receiver, method_call))
diff --git a/src/librustdoc/clean/auto_trait.rs b/src/librustdoc/clean/auto_trait.rs
index 26487605bac67..fde8648c0c40a 100644
--- a/src/librustdoc/clean/auto_trait.rs
+++ b/src/librustdoc/clean/auto_trait.rs
@@ -84,7 +84,7 @@ impl<'a, 'tcx, 'rcx, 'cstore> AutoTraitFinder<'a, 'tcx, 'rcx, 'cstore> {
             .into_iter()
             .chain(self.get_auto_trait_impl_for(
                 def_id,
-                name.clone(),
+                name,
                 generics.clone(),
                 def_ctor,
                 tcx.require_lang_item(lang_items::SyncTraitLangItem),
diff --git a/src/librustdoc/clean/blanket_impl.rs b/src/librustdoc/clean/blanket_impl.rs
index b6bc8d603d5ac..858685ef00e37 100644
--- a/src/librustdoc/clean/blanket_impl.rs
+++ b/src/librustdoc/clean/blanket_impl.rs
@@ -66,7 +66,7 @@ impl<'a, 'tcx, 'rcx, 'cstore> BlanketImplFinder <'a, 'tcx, 'rcx, 'cstore> {
         }
         let ty = self.cx.tcx.type_of(def_id);
         let generics = self.cx.tcx.generics_of(def_id);
-        let real_name = name.clone().map(|name| Ident::from_str(&name));
+        let real_name = name.map(|name| Ident::from_str(&name));
         let param_env = self.cx.tcx.param_env(def_id);
         for &trait_def_id in self.cx.all_traits.iter() {
             if !self.cx.renderinfo.borrow().access_levels.is_doc_reachable(trait_def_id) ||
@@ -109,7 +109,7 @@ impl<'a, 'tcx, 'rcx, 'cstore> BlanketImplFinder <'a, 'tcx, 'rcx, 'cstore> {
                         );
                         let may_apply = match infcx.evaluate_obligation(
                             &traits::Obligation::new(
-                                cause.clone(),
+                                cause,
                                 param_env,
                                 trait_ref.to_predicate(),
                             ),
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 9b2720717c9b3..88240e844edc2 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -3611,7 +3611,7 @@ impl ToSource for syntax_pos::Span {
     fn to_src(&self, cx: &DocContext) -> String {
         debug!("converting span {:?} to snippet", self.clean(cx));
         let sn = match cx.sess().source_map().span_to_snippet(*self) {
-            Ok(x) => x.to_string(),
+            Ok(x) => x,
             Err(_) => String::new()
         };
         debug!("got snippet {}", sn);
diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index dda0f37c3f95b..9dfe77338a356 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -521,7 +521,7 @@ pub fn run(mut krate: clean::Crate,
             external_html: external_html.clone(),
             krate: krate.name.clone(),
         },
-        css_file_extension: css_file_extension.clone(),
+        css_file_extension,
         created_dirs: Default::default(),
         sort_modules_alphabetically,
         themes,
@@ -1343,7 +1343,7 @@ impl DocFolder for Cache {
                         self.search_index.push(IndexItem {
                             ty: item.type_(),
                             name: s.to_string(),
-                            path: path.join("::").to_string(),
+                            path: path.join("::"),
                             desc: plain_summary_line(item.doc_value()),
                             parent,
                             parent_idx: None,
@@ -2283,7 +2283,7 @@ fn document_short(w: &mut fmt::Formatter, cx: &Context, item: &clean::Item, link
             format!("{} [Read more]({})",
                     &plain_summary_line(Some(s)), naive_assoc_href(item, link))
         } else {
-            plain_summary_line(Some(s)).to_string()
+            plain_summary_line(Some(s))
         };
         render_markdown(w, cx, &markdown, item.links(), prefix)?;
     } else if !prefix.is_empty() {
@@ -2435,7 +2435,7 @@ fn item_module(w: &mut fmt::Formatter, cx: &Context,
     // (which is the position in the vector).
     indices.dedup_by_key(|i| (items[*i].def_id,
                               if items[*i].name.as_ref().is_some() {
-                                  Some(full_path(cx, &items[*i]).clone())
+                                  Some(full_path(cx, &items[*i]))
                               } else {
                                   None
                               },
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 406180c09e8e4..45a0494849bfa 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -460,7 +460,7 @@ fn main_args(args: &[String]) -> isize {
     let externs = match parse_externs(&matches) {
         Ok(ex) => ex,
         Err(err) => {
-            diag.struct_err(&err.to_string()).emit();
+            diag.struct_err(&err).emit();
             return 1;
         }
     };
diff --git a/src/librustdoc/test.rs b/src/librustdoc/test.rs
index 85cd0f84e1cb0..2e6e76b5a4039 100644
--- a/src/librustdoc/test.rs
+++ b/src/librustdoc/test.rs
@@ -208,7 +208,7 @@ fn run_test(test: &str, cratename: &str, filename: &FileName, line: usize,
     // needs to be the result of SourceMap::span_to_unmapped_path
     let input = config::Input::Str {
         name: filename.to_owned(),
-        input: test.to_owned(),
+        input: test,
     };
     let outputs = OutputTypes::new(&[(OutputType::Exe, None)]);
 
@@ -350,7 +350,7 @@ fn run_test(test: &str, cratename: &str, filename: &FileName, line: usize,
     let newpath = {
         let path = env::var_os(var).unwrap_or(OsString::new());
         let mut path = env::split_paths(&path).collect::<Vec<_>>();
-        path.insert(0, libdir.clone());
+        path.insert(0, libdir);
         env::join_paths(path).unwrap()
     };
     cmd.env(var, &newpath);
diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 805aa9bef227d..36190b3273a5a 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -133,8 +133,7 @@ fn generic_extension<'cx>(cx: &'cx mut ExtCtxt,
                 // Replace all the tokens for the corresponding positions in the macro, to maintain
                 // proper positions in error reporting, while maintaining the macro_backtrace.
                 if rhs_spans.len() == tts.len() {
-                    tts = tts.map_enumerated(|i, tt| {
-                        let mut tt = tt.clone();
+                    tts = tts.map_enumerated(|i, mut tt| {
                         let mut sp = rhs_spans[i];
                         sp = sp.with_ctxt(tt.span().ctxt());
                         tt.set_span(sp);
diff --git a/src/libsyntax/ext/tt/transcribe.rs b/src/libsyntax/ext/tt/transcribe.rs
index ae486158fee69..3d897d17e0b5c 100644
--- a/src/libsyntax/ext/tt/transcribe.rs
+++ b/src/libsyntax/ext/tt/transcribe.rs
@@ -219,9 +219,9 @@ impl Add for LockstepIterSize {
             LockstepIterSize::Unconstrained => other,
             LockstepIterSize::Contradiction(_) => self,
             LockstepIterSize::Constraint(l_len, ref l_id) => match other {
-                LockstepIterSize::Unconstrained => self.clone(),
+                LockstepIterSize::Unconstrained => self,
                 LockstepIterSize::Contradiction(_) => other,
-                LockstepIterSize::Constraint(r_len, _) if l_len == r_len => self.clone(),
+                LockstepIterSize::Constraint(r_len, _) if l_len == r_len => self,
                 LockstepIterSize::Constraint(r_len, r_id) => {
                     let msg = format!("inconsistent lockstep iteration: \
                                        '{}' has {} items, but '{}' has {}",
diff --git a/src/libsyntax/test.rs b/src/libsyntax/test.rs
index 9f554a90afbc4..8ff4b0d025c8d 100644
--- a/src/libsyntax/test.rs
+++ b/src/libsyntax/test.rs
@@ -346,7 +346,7 @@ fn mk_main(cx: &mut TestCtxt) -> P<ast::Item> {
 
     test_runner.span = sp;
 
-    let test_main_path_expr = ecx.expr_path(test_runner.clone());
+    let test_main_path_expr = ecx.expr_path(test_runner);
     let call_test_main = ecx.expr_call(sp, test_main_path_expr,
                                        vec![mk_tests_slice(cx)]);
     let call_test_main = ecx.stmt_expr(call_test_main);
diff --git a/src/libsyntax_ext/deriving/cmp/partial_ord.rs b/src/libsyntax_ext/deriving/cmp/partial_ord.rs
index 3705a245584d0..32a58de3529fd 100644
--- a/src/libsyntax_ext/deriving/cmp/partial_ord.rs
+++ b/src/libsyntax_ext/deriving/cmp/partial_ord.rs
@@ -178,7 +178,7 @@ pub fn cs_partial_cmp(cx: &mut ExtCtxt, span: Span, substr: &Substructure) -> P<
 
                 cx.expr_match(span, new, vec![eq_arm, neq_arm])
             },
-            equals_expr.clone(),
+            equals_expr,
             Box::new(|cx, span, (self_args, tag_tuple), _non_self_args| {
         if self_args.len() != 2 {
             cx.span_bug(span, "not exactly 2 arguments in `derive(PartialOrd)`")
diff --git a/src/libsyntax_ext/deriving/custom.rs b/src/libsyntax_ext/deriving/custom.rs
index 973ad631b8343..55b3928d68eee 100644
--- a/src/libsyntax_ext/deriving/custom.rs
+++ b/src/libsyntax_ext/deriving/custom.rs
@@ -75,7 +75,7 @@ impl MultiItemModifier for ProcMacroDerive {
         // Mark attributes as known, and used.
         MarkAttrs(&self.attrs).visit_item(&item);
 
-        let input = __internal::new_token_stream(ecx.resolver.eliminate_crate_var(item.clone()));
+        let input = __internal::new_token_stream(ecx.resolver.eliminate_crate_var(item));
         let res = __internal::set_sess(ecx, || {
             let inner = self.inner;
             panic::catch_unwind(panic::AssertUnwindSafe(|| inner(input)))