From 299d696b91e833f01f37e97b69767fcf6f5cccf0 Mon Sep 17 00:00:00 2001
From: Caio <c410.f3r@gmail.com>
Date: Thu, 29 Aug 2019 20:44:30 -0300
Subject: [PATCH 01/11] Stabilize `param_attrs` in Rust 1.39.0

---
 .../src/language-features/param-attrs.md      |  27 -----
 src/libsyntax/feature_gate/accepted.rs        |   2 +
 src/libsyntax/feature_gate/active.rs          |   3 -
 src/libsyntax/feature_gate/check.rs           |   1 -
 src/libsyntax/parse/attr.rs                   |   7 --
 src/libsyntax/parse/mod.rs                    |   2 -
 src/libsyntax/parse/parser.rs                 |   4 +-
 src/libsyntax/parse/parser/expr.rs            |   2 +-
 src/test/ui/lint/lint-unused-mut-variables.rs |   2 +-
 src/test/ui/lint/lint-unused-variables.rs     |   2 +-
 src/test/ui/parser/fn-arg-doc-comment.rs      |   4 -
 src/test/ui/parser/fn-arg-doc-comment.stderr  |  33 ++----
 .../rfc-2565-param-attrs/param-attrs-2018.rs  |   2 -
 .../param-attrs-2018.stderr                   |   2 +-
 .../param-attrs-allowed.rs                    |   1 -
 .../param-attrs-builtin-attrs.rs              |   2 -
 .../param-attrs-builtin-attrs.stderr          | 104 +++++++++---------
 .../rfc-2565-param-attrs/param-attrs-cfg.rs   |   2 +-
 .../param-attrs-feature-gate.rs               |  16 ---
 .../param-attrs-feature-gate.stderr           |  27 -----
 .../param-attrs-pretty.rs                     |   1 -
 .../proc-macro-cannot-be-used.rs              |   1 -
 .../proc-macro-cannot-be-used.stderr          |  50 ++++-----
 23 files changed, 93 insertions(+), 204 deletions(-)
 delete mode 100644 src/doc/unstable-book/src/language-features/param-attrs.md
 delete mode 100644 src/test/ui/rfc-2565-param-attrs/param-attrs-feature-gate.rs
 delete mode 100644 src/test/ui/rfc-2565-param-attrs/param-attrs-feature-gate.stderr

diff --git a/src/doc/unstable-book/src/language-features/param-attrs.md b/src/doc/unstable-book/src/language-features/param-attrs.md
deleted file mode 100644
index 4b83c204ba105..0000000000000
--- a/src/doc/unstable-book/src/language-features/param-attrs.md
+++ /dev/null
@@ -1,27 +0,0 @@
-# `param_attrs`
-
-The tracking issue for this feature is: [#60406]
-
-[#60406]: https://github.com/rust-lang/rust/issues/60406
-
-Allow attributes in formal function parameter position so external tools and compiler internals can
-take advantage of the additional information that the parameters provide.
-
-Enables finer conditional compilation with `#[cfg(..)]` and linting control of variables. Moreover,
-opens the path to richer DSLs created by users.
-
-------------------------
-
-Example:
-
-```rust
-#![feature(param_attrs)]
-
-fn len(
-  #[cfg(windows)] slice: &[u16],
-  #[cfg(not(windows))] slice: &[u8],
-) -> usize
-{
-  slice.len()
-}
-```
diff --git a/src/libsyntax/feature_gate/accepted.rs b/src/libsyntax/feature_gate/accepted.rs
index eff9f90a8619e..5538daf388e2f 100644
--- a/src/libsyntax/feature_gate/accepted.rs
+++ b/src/libsyntax/feature_gate/accepted.rs
@@ -243,6 +243,8 @@ declare_features! (
     (accepted, async_await, "1.39.0", Some(50547), None),
     /// Allows mixing bind-by-move in patterns and references to those identifiers in guards.
     (accepted, bind_by_move_pattern_guards, "1.39.0", Some(15287), None),
+    /// Allows attributes in formal function parameters.
+    (accepted, param_attrs, "1.39.0", Some(60406), None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: accepted features
diff --git a/src/libsyntax/feature_gate/active.rs b/src/libsyntax/feature_gate/active.rs
index dd78777b56986..38c16dbac6ab7 100644
--- a/src/libsyntax/feature_gate/active.rs
+++ b/src/libsyntax/feature_gate/active.rs
@@ -489,9 +489,6 @@ declare_features! (
     /// Allows the user of associated type bounds.
     (active, associated_type_bounds, "1.34.0", Some(52662), None),
 
-    /// Attributes on formal function params.
-    (active, param_attrs, "1.36.0", Some(60406), None),
-
     /// Allows calling constructor functions in `const fn`.
     (active, const_constructor, "1.37.0", Some(61456), None),
 
diff --git a/src/libsyntax/feature_gate/check.rs b/src/libsyntax/feature_gate/check.rs
index 5711b269ff092..6b76a6a60c3d6 100644
--- a/src/libsyntax/feature_gate/check.rs
+++ b/src/libsyntax/feature_gate/check.rs
@@ -892,7 +892,6 @@ pub fn check_crate(krate: &ast::Crate,
         }
     }
 
-    gate_all!(param_attrs, "attributes on function parameters are unstable");
     gate_all!(let_chains, "`let` expressions in this position are experimental");
     gate_all!(async_closure, "async closures are unstable");
     gate_all!(yields, generators, "yield syntax is experimental");
diff --git a/src/libsyntax/parse/attr.rs b/src/libsyntax/parse/attr.rs
index 9aa1ec0b14fe9..bba70973631fe 100644
--- a/src/libsyntax/parse/attr.rs
+++ b/src/libsyntax/parse/attr.rs
@@ -19,13 +19,6 @@ const DEFAULT_UNEXPECTED_INNER_ATTR_ERR_MSG: &str = "an inner attribute is not \
                                                      permitted in this context";
 
 impl<'a> Parser<'a> {
-    crate fn parse_param_attributes(&mut self) -> PResult<'a, Vec<ast::Attribute>> {
-        let attrs = self.parse_outer_attributes()?;
-        self.sess.gated_spans.param_attrs.borrow_mut()
-            .extend(attrs.iter().map(|a| a.span));
-        Ok(attrs)
-    }
-
     /// Parses attributes that appear before an item.
     crate fn parse_outer_attributes(&mut self) -> PResult<'a, Vec<ast::Attribute>> {
         let mut attrs: Vec<ast::Attribute> = Vec::new();
diff --git a/src/libsyntax/parse/mod.rs b/src/libsyntax/parse/mod.rs
index bc1bc00ac8405..6a8a64f369d99 100644
--- a/src/libsyntax/parse/mod.rs
+++ b/src/libsyntax/parse/mod.rs
@@ -42,8 +42,6 @@ pub type PResult<'a, T> = Result<T, DiagnosticBuilder<'a>>;
 /// used and should be feature gated accordingly in `check_crate`.
 #[derive(Default)]
 pub struct GatedSpans {
-    /// Spans collected for gating `param_attrs`, e.g. `fn foo(#[attr] x: u8) {}`.
-    pub param_attrs: Lock<Vec<Span>>,
     /// Spans collected for gating `let_chains`, e.g. `if a && let b = c {}`.
     pub let_chains: Lock<Vec<Span>>,
     /// Spans collected for gating `async_closure`, e.g. `async || ..`.
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index fcebfa2996233..b2b6504919e96 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -979,7 +979,7 @@ impl<'a> Parser<'a> {
         is_name_required: impl Fn(&token::Token) -> bool,
     ) -> PResult<'a, Param> {
         let lo = self.token.span;
-        let attrs = self.parse_param_attributes()?;
+        let attrs = self.parse_outer_attributes()?;
         if let Some(mut param) = self.parse_self_param()? {
             param.attrs = attrs.into();
             return self.recover_bad_self_param(param, is_trait_item);
@@ -1362,7 +1362,7 @@ impl<'a> Parser<'a> {
     /// Returns the parsed optional self parameter with attributes and whether a self
     /// shortcut was used.
     fn parse_self_parameter_with_attrs(&mut self) -> PResult<'a, Option<Param>> {
-        let attrs = self.parse_param_attributes()?;
+        let attrs = self.parse_outer_attributes()?;
         let param_opt = self.parse_self_param()?;
         Ok(param_opt.map(|mut param| {
             param.attrs = attrs.into();
diff --git a/src/libsyntax/parse/parser/expr.rs b/src/libsyntax/parse/parser/expr.rs
index 31b28443abbc3..b383498b7b64d 100644
--- a/src/libsyntax/parse/parser/expr.rs
+++ b/src/libsyntax/parse/parser/expr.rs
@@ -1176,7 +1176,7 @@ impl<'a> Parser<'a> {
     /// Parses a parameter in a closure header (e.g., `|arg, arg|`).
     fn parse_fn_block_param(&mut self) -> PResult<'a, Param> {
         let lo = self.token.span;
-        let attrs = self.parse_param_attributes()?;
+        let attrs = self.parse_outer_attributes()?;
         let pat = self.parse_pat(PARAM_EXPECTED)?;
         let t = if self.eat(&token::Colon) {
             self.parse_ty()?
diff --git a/src/test/ui/lint/lint-unused-mut-variables.rs b/src/test/ui/lint/lint-unused-mut-variables.rs
index f140546b04819..1af44ecf362bf 100644
--- a/src/test/ui/lint/lint-unused-mut-variables.rs
+++ b/src/test/ui/lint/lint-unused-mut-variables.rs
@@ -3,7 +3,7 @@
 // Exercise the unused_mut attribute in some positive and negative cases
 
 #![deny(unused_mut)]
-#![feature(async_closure, param_attrs)]
+#![feature(async_closure)]
 
 async fn baz_async(
     mut a: i32,
diff --git a/src/test/ui/lint/lint-unused-variables.rs b/src/test/ui/lint/lint-unused-variables.rs
index 06b818636f956..1a6b5183f0fae 100644
--- a/src/test/ui/lint/lint-unused-variables.rs
+++ b/src/test/ui/lint/lint-unused-variables.rs
@@ -1,7 +1,7 @@
 // compile-flags: --cfg something
 // edition:2018
 
-#![feature(async_closure, param_attrs)]
+#![feature(async_closure)]
 #![deny(unused_variables)]
 
 async fn foo_async(
diff --git a/src/test/ui/parser/fn-arg-doc-comment.rs b/src/test/ui/parser/fn-arg-doc-comment.rs
index 4a4f959e21353..995eb62d0bb59 100644
--- a/src/test/ui/parser/fn-arg-doc-comment.rs
+++ b/src/test/ui/parser/fn-arg-doc-comment.rs
@@ -2,14 +2,10 @@ pub fn f(
     /// Comment
     //~^ ERROR documentation comments cannot be applied to function parameters
     //~| NOTE doc comments are not allowed here
-    //~| ERROR attributes on function parameters are unstable
-    //~| NOTE https://github.com/rust-lang/rust/issues/60406
     id: u8,
     /// Other
     //~^ ERROR documentation comments cannot be applied to function parameters
     //~| NOTE doc comments are not allowed here
-    //~| ERROR attributes on function parameters are unstable
-    //~| NOTE https://github.com/rust-lang/rust/issues/60406
     a: u8,
 ) {}
 
diff --git a/src/test/ui/parser/fn-arg-doc-comment.stderr b/src/test/ui/parser/fn-arg-doc-comment.stderr
index d8884de1fe84d..669785af45f93 100644
--- a/src/test/ui/parser/fn-arg-doc-comment.stderr
+++ b/src/test/ui/parser/fn-arg-doc-comment.stderr
@@ -1,5 +1,5 @@
 error: attributes cannot be applied to a function parameter's type
-  --> $DIR/fn-arg-doc-comment.rs:16:12
+  --> $DIR/fn-arg-doc-comment.rs:12:12
    |
 LL | fn bar(id: #[allow(dead_code)] i32) {}
    |            ^^^^^^^^^^^^^^^^^^^ attributes are not allowed here
@@ -11,31 +11,13 @@ LL |     /// Comment
    |     ^^^^^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/fn-arg-doc-comment.rs:8:5
+  --> $DIR/fn-arg-doc-comment.rs:6:5
    |
 LL |     /// Other
    |     ^^^^^^^^^ doc comments are not allowed here
 
-error[E0658]: attributes on function parameters are unstable
-  --> $DIR/fn-arg-doc-comment.rs:2:5
-   |
-LL |     /// Comment
-   |     ^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/60406
-   = help: add `#![feature(param_attrs)]` to the crate attributes to enable
-
-error[E0658]: attributes on function parameters are unstable
-  --> $DIR/fn-arg-doc-comment.rs:8:5
-   |
-LL |     /// Other
-   |     ^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/60406
-   = help: add `#![feature(param_attrs)]` to the crate attributes to enable
-
 error[E0308]: mismatched types
-  --> $DIR/fn-arg-doc-comment.rs:22:7
+  --> $DIR/fn-arg-doc-comment.rs:18:7
    |
 LL |     f("", "");
    |       ^^ expected u8, found reference
@@ -44,7 +26,7 @@ LL |     f("", "");
               found type `&'static str`
 
 error[E0308]: mismatched types
-  --> $DIR/fn-arg-doc-comment.rs:22:11
+  --> $DIR/fn-arg-doc-comment.rs:18:11
    |
 LL |     f("", "");
    |           ^^ expected u8, found reference
@@ -53,7 +35,7 @@ LL |     f("", "");
               found type `&'static str`
 
 error[E0308]: mismatched types
-  --> $DIR/fn-arg-doc-comment.rs:29:9
+  --> $DIR/fn-arg-doc-comment.rs:25:9
    |
 LL |     bar("");
    |         ^^ expected i32, found reference
@@ -61,7 +43,6 @@ LL |     bar("");
    = note: expected type `i32`
               found type `&'static str`
 
-error: aborting due to 8 previous errors
+error: aborting due to 6 previous errors
 
-Some errors have detailed explanations: E0308, E0658.
-For more information about an error, try `rustc --explain E0308`.
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/rfc-2565-param-attrs/param-attrs-2018.rs b/src/test/ui/rfc-2565-param-attrs/param-attrs-2018.rs
index d71711336b06e..a6f693bd5b5f4 100644
--- a/src/test/ui/rfc-2565-param-attrs/param-attrs-2018.rs
+++ b/src/test/ui/rfc-2565-param-attrs/param-attrs-2018.rs
@@ -1,7 +1,5 @@
 // edition:2018
 
-#![feature(param_attrs)]
-
 trait Trait2015 { fn foo(#[allow(C)] i32); }
 //~^ ERROR expected one of `:`, `@`, or `|`, found `)`
 
diff --git a/src/test/ui/rfc-2565-param-attrs/param-attrs-2018.stderr b/src/test/ui/rfc-2565-param-attrs/param-attrs-2018.stderr
index 26b414e426805..9860e9805b2ed 100644
--- a/src/test/ui/rfc-2565-param-attrs/param-attrs-2018.stderr
+++ b/src/test/ui/rfc-2565-param-attrs/param-attrs-2018.stderr
@@ -1,5 +1,5 @@
 error: expected one of `:`, `@`, or `|`, found `)`
-  --> $DIR/param-attrs-2018.rs:5:41
+  --> $DIR/param-attrs-2018.rs:3:41
    |
 LL | trait Trait2015 { fn foo(#[allow(C)] i32); }
    |                                         ^ expected one of `:`, `@`, or `|` here
diff --git a/src/test/ui/rfc-2565-param-attrs/param-attrs-allowed.rs b/src/test/ui/rfc-2565-param-attrs/param-attrs-allowed.rs
index 5eeda66173ded..1217f89cb3168 100644
--- a/src/test/ui/rfc-2565-param-attrs/param-attrs-allowed.rs
+++ b/src/test/ui/rfc-2565-param-attrs/param-attrs-allowed.rs
@@ -2,7 +2,6 @@
 // compile-flags: --cfg something
 
 #![deny(unused_mut)]
-#![feature(param_attrs)]
 
 extern "C" {
     fn ffi(
diff --git a/src/test/ui/rfc-2565-param-attrs/param-attrs-builtin-attrs.rs b/src/test/ui/rfc-2565-param-attrs/param-attrs-builtin-attrs.rs
index a8fe5d6c1f60e..c4684a3fa82b0 100644
--- a/src/test/ui/rfc-2565-param-attrs/param-attrs-builtin-attrs.rs
+++ b/src/test/ui/rfc-2565-param-attrs/param-attrs-builtin-attrs.rs
@@ -1,5 +1,3 @@
-#![feature(param_attrs)]
-
 extern "C" {
     fn ffi(
         /// Foo
diff --git a/src/test/ui/rfc-2565-param-attrs/param-attrs-builtin-attrs.stderr b/src/test/ui/rfc-2565-param-attrs/param-attrs-builtin-attrs.stderr
index 8ab3fc39a0ccb..0fc6ca2f7f37a 100644
--- a/src/test/ui/rfc-2565-param-attrs/param-attrs-builtin-attrs.stderr
+++ b/src/test/ui/rfc-2565-param-attrs/param-attrs-builtin-attrs.stderr
@@ -1,311 +1,311 @@
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/param-attrs-builtin-attrs.rs:7:9
+  --> $DIR/param-attrs-builtin-attrs.rs:5:9
    |
 LL |         #[test] a: i32,
    |         ^^^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/param-attrs-builtin-attrs.rs:23:5
+  --> $DIR/param-attrs-builtin-attrs.rs:21:5
    |
 LL |     #[test] a: u32,
    |     ^^^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/param-attrs-builtin-attrs.rs:38:5
+  --> $DIR/param-attrs-builtin-attrs.rs:36:5
    |
 LL |     #[test] a: u32,
    |     ^^^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/param-attrs-builtin-attrs.rs:58:9
+  --> $DIR/param-attrs-builtin-attrs.rs:56:9
    |
 LL |         #[test] a: i32,
    |         ^^^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/param-attrs-builtin-attrs.rs:79:9
+  --> $DIR/param-attrs-builtin-attrs.rs:77:9
    |
 LL |         #[test] a: i32,
    |         ^^^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/param-attrs-builtin-attrs.rs:98:9
+  --> $DIR/param-attrs-builtin-attrs.rs:96:9
    |
 LL |         #[test] a: i32,
    |         ^^^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/param-attrs-builtin-attrs.rs:117:9
+  --> $DIR/param-attrs-builtin-attrs.rs:115:9
    |
 LL |         #[test] a: i32,
    |         ^^^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/param-attrs-builtin-attrs.rs:134:9
+  --> $DIR/param-attrs-builtin-attrs.rs:132:9
    |
 LL |         #[test] a: u32,
    |         ^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:5:9
+  --> $DIR/param-attrs-builtin-attrs.rs:3:9
    |
 LL |         /// Foo
    |         ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:9:9
+  --> $DIR/param-attrs-builtin-attrs.rs:7:9
    |
 LL |         /// Bar
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:11:9
+  --> $DIR/param-attrs-builtin-attrs.rs:9:9
    |
 LL |         #[must_use]
    |         ^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:13:9
+  --> $DIR/param-attrs-builtin-attrs.rs:11:9
    |
 LL |         /// Baz
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:15:9
+  --> $DIR/param-attrs-builtin-attrs.rs:13:9
    |
 LL |         #[no_mangle] b: i32,
    |         ^^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:21:5
+  --> $DIR/param-attrs-builtin-attrs.rs:19:5
    |
 LL |     /// Foo
    |     ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:25:5
+  --> $DIR/param-attrs-builtin-attrs.rs:23:5
    |
 LL |     /// Bar
    |     ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:27:5
+  --> $DIR/param-attrs-builtin-attrs.rs:25:5
    |
 LL |     #[must_use]
    |     ^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:29:5
+  --> $DIR/param-attrs-builtin-attrs.rs:27:5
    |
 LL |     /// Baz
    |     ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:31:5
+  --> $DIR/param-attrs-builtin-attrs.rs:29:5
    |
 LL |     #[no_mangle] b: i32,
    |     ^^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:36:5
+  --> $DIR/param-attrs-builtin-attrs.rs:34:5
    |
 LL |     /// Foo
    |     ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:40:5
+  --> $DIR/param-attrs-builtin-attrs.rs:38:5
    |
 LL |     /// Bar
    |     ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:42:5
+  --> $DIR/param-attrs-builtin-attrs.rs:40:5
    |
 LL |     #[must_use]
    |     ^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:44:5
+  --> $DIR/param-attrs-builtin-attrs.rs:42:5
    |
 LL |     /// Baz
    |     ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:46:5
+  --> $DIR/param-attrs-builtin-attrs.rs:44:5
    |
 LL |     #[no_mangle] b: i32,
    |     ^^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:53:9
+  --> $DIR/param-attrs-builtin-attrs.rs:51:9
    |
 LL |         /// Foo
    |         ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:56:9
+  --> $DIR/param-attrs-builtin-attrs.rs:54:9
    |
 LL |         /// Bar
    |         ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:60:9
+  --> $DIR/param-attrs-builtin-attrs.rs:58:9
    |
 LL |         /// Baz
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:62:9
+  --> $DIR/param-attrs-builtin-attrs.rs:60:9
    |
 LL |         #[must_use]
    |         ^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:64:9
+  --> $DIR/param-attrs-builtin-attrs.rs:62:9
    |
 LL |         /// Qux
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:66:9
+  --> $DIR/param-attrs-builtin-attrs.rs:64:9
    |
 LL |         #[no_mangle] b: i32,
    |         ^^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:74:9
+  --> $DIR/param-attrs-builtin-attrs.rs:72:9
    |
 LL |         /// Foo
    |         ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:77:9
+  --> $DIR/param-attrs-builtin-attrs.rs:75:9
    |
 LL |         /// Bar
    |         ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:81:9
+  --> $DIR/param-attrs-builtin-attrs.rs:79:9
    |
 LL |         /// Baz
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:83:9
+  --> $DIR/param-attrs-builtin-attrs.rs:81:9
    |
 LL |         #[must_use]
    |         ^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:85:9
+  --> $DIR/param-attrs-builtin-attrs.rs:83:9
    |
 LL |         /// Qux
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:87:9
+  --> $DIR/param-attrs-builtin-attrs.rs:85:9
    |
 LL |         #[no_mangle] b: i32,
    |         ^^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:93:9
+  --> $DIR/param-attrs-builtin-attrs.rs:91:9
    |
 LL |         /// Foo
    |         ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:96:9
+  --> $DIR/param-attrs-builtin-attrs.rs:94:9
    |
 LL |         /// Bar
    |         ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:100:9
+  --> $DIR/param-attrs-builtin-attrs.rs:98:9
    |
 LL |         /// Baz
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:102:9
+  --> $DIR/param-attrs-builtin-attrs.rs:100:9
    |
 LL |         #[must_use]
    |         ^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:104:9
+  --> $DIR/param-attrs-builtin-attrs.rs:102:9
    |
 LL |         /// Qux
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:106:9
+  --> $DIR/param-attrs-builtin-attrs.rs:104:9
    |
 LL |         #[no_mangle] b: i32,
    |         ^^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:112:9
+  --> $DIR/param-attrs-builtin-attrs.rs:110:9
    |
 LL |         /// Foo
    |         ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:115:9
+  --> $DIR/param-attrs-builtin-attrs.rs:113:9
    |
 LL |         /// Bar
    |         ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:119:9
+  --> $DIR/param-attrs-builtin-attrs.rs:117:9
    |
 LL |         /// Baz
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:121:9
+  --> $DIR/param-attrs-builtin-attrs.rs:119:9
    |
 LL |         #[must_use]
    |         ^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:123:9
+  --> $DIR/param-attrs-builtin-attrs.rs:121:9
    |
 LL |         /// Qux
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:125:9
+  --> $DIR/param-attrs-builtin-attrs.rs:123:9
    |
 LL |         #[no_mangle] b: i32,
    |         ^^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:132:9
+  --> $DIR/param-attrs-builtin-attrs.rs:130:9
    |
 LL |         /// Foo
    |         ^^^^^^^ doc comments are not allowed here
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:136:9
+  --> $DIR/param-attrs-builtin-attrs.rs:134:9
    |
 LL |         /// Bar
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:138:9
+  --> $DIR/param-attrs-builtin-attrs.rs:136:9
    |
 LL |         #[must_use]
    |         ^^^^^^^^^^^
 
 error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:140:9
+  --> $DIR/param-attrs-builtin-attrs.rs:138:9
    |
 LL |         /// Baz
    |         ^^^^^^^ doc comments are not allowed here
 
 error: allow, cfg, cfg_attr, deny, forbid, and warn are the only allowed built-in attributes in function parameters
-  --> $DIR/param-attrs-builtin-attrs.rs:142:9
+  --> $DIR/param-attrs-builtin-attrs.rs:140:9
    |
 LL |         #[no_mangle] b: i32
    |         ^^^^^^^^^^^^
diff --git a/src/test/ui/rfc-2565-param-attrs/param-attrs-cfg.rs b/src/test/ui/rfc-2565-param-attrs/param-attrs-cfg.rs
index 5ad6e23cf2a63..d44ff14e99247 100644
--- a/src/test/ui/rfc-2565-param-attrs/param-attrs-cfg.rs
+++ b/src/test/ui/rfc-2565-param-attrs/param-attrs-cfg.rs
@@ -1,7 +1,7 @@
 // compile-flags: --cfg something
 // edition:2018
 
-#![feature(async_closure, param_attrs)]
+#![feature(async_closure)]
 #![deny(unused_variables)]
 
 extern "C" {
diff --git a/src/test/ui/rfc-2565-param-attrs/param-attrs-feature-gate.rs b/src/test/ui/rfc-2565-param-attrs/param-attrs-feature-gate.rs
deleted file mode 100644
index a7f4855915b24..0000000000000
--- a/src/test/ui/rfc-2565-param-attrs/param-attrs-feature-gate.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-// gate-test-param_attrs
-
-#![deny(unused_variables)]
-
-fn foo(
-    /// Foo
-    //~^ ERROR documentation comments cannot be applied to function parameters
-    //~| NOTE doc comments are not allowed here
-    //~| ERROR attributes on function parameters are unstable
-    //~| NOTE https://github.com/rust-lang/rust/issues/60406
-    #[allow(unused_variables)] a: u8
-    //~^ ERROR attributes on function parameters are unstable
-    //~| NOTE https://github.com/rust-lang/rust/issues/60406
-) {}
-
-fn main() {}
diff --git a/src/test/ui/rfc-2565-param-attrs/param-attrs-feature-gate.stderr b/src/test/ui/rfc-2565-param-attrs/param-attrs-feature-gate.stderr
deleted file mode 100644
index 0bb9d05dca0ac..0000000000000
--- a/src/test/ui/rfc-2565-param-attrs/param-attrs-feature-gate.stderr
+++ /dev/null
@@ -1,27 +0,0 @@
-error: documentation comments cannot be applied to function parameters
-  --> $DIR/param-attrs-feature-gate.rs:6:5
-   |
-LL |     /// Foo
-   |     ^^^^^^^ doc comments are not allowed here
-
-error[E0658]: attributes on function parameters are unstable
-  --> $DIR/param-attrs-feature-gate.rs:6:5
-   |
-LL |     /// Foo
-   |     ^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/60406
-   = help: add `#![feature(param_attrs)]` to the crate attributes to enable
-
-error[E0658]: attributes on function parameters are unstable
-  --> $DIR/param-attrs-feature-gate.rs:11:5
-   |
-LL |     #[allow(unused_variables)] a: u8
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: for more information, see https://github.com/rust-lang/rust/issues/60406
-   = help: add `#![feature(param_attrs)]` to the crate attributes to enable
-
-error: aborting due to 3 previous errors
-
-For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/rfc-2565-param-attrs/param-attrs-pretty.rs b/src/test/ui/rfc-2565-param-attrs/param-attrs-pretty.rs
index 1a7e948174506..fb86020d992e9 100644
--- a/src/test/ui/rfc-2565-param-attrs/param-attrs-pretty.rs
+++ b/src/test/ui/rfc-2565-param-attrs/param-attrs-pretty.rs
@@ -2,7 +2,6 @@
 
 // check-pass
 
-#![feature(param_attrs)]
 #![feature(c_variadic)]
 
 extern crate param_attrs;
diff --git a/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.rs b/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.rs
index 7f00308925442..9f4e2710dc420 100644
--- a/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.rs
+++ b/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.rs
@@ -1,6 +1,5 @@
 // aux-build:ident-mac.rs
 
-#![feature(param_attrs)]
 #![feature(c_variadic)]
 
 extern crate ident_mac;
diff --git a/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.stderr b/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.stderr
index 3b72e8ab4bdf9..b4946fa74943f 100644
--- a/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.stderr
+++ b/src/test/ui/rfc-2565-param-attrs/proc-macro-cannot-be-used.stderr
@@ -1,149 +1,149 @@
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:11:21
+  --> $DIR/proc-macro-cannot-be-used.rs:10:21
    |
 LL | extern "C" { fn ffi(#[id] arg1: i32, #[id] ...); }
    |                     ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:11:38
+  --> $DIR/proc-macro-cannot-be-used.rs:10:38
    |
 LL | extern "C" { fn ffi(#[id] arg1: i32, #[id] ...); }
    |                                      ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:15:38
+  --> $DIR/proc-macro-cannot-be-used.rs:14:38
    |
 LL | unsafe extern "C" fn cvar(arg1: i32, #[id] mut args: ...) {}
    |                                      ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:18:28
+  --> $DIR/proc-macro-cannot-be-used.rs:17:28
    |
 LL | type Alias = extern "C" fn(#[id] u8, #[id] ...);
    |                            ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:18:38
+  --> $DIR/proc-macro-cannot-be-used.rs:17:38
    |
 LL | type Alias = extern "C" fn(#[id] u8, #[id] ...);
    |                                      ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:22:9
+  --> $DIR/proc-macro-cannot-be-used.rs:21:9
    |
 LL | fn free(#[id] arg1: u8) {
    |         ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:24:16
+  --> $DIR/proc-macro-cannot-be-used.rs:23:16
    |
 LL |     let lam = |#[id] W(x), #[id] y| ();
    |                ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:24:28
+  --> $DIR/proc-macro-cannot-be-used.rs:23:28
    |
 LL |     let lam = |#[id] W(x), #[id] y| ();
    |                            ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:30:18
+  --> $DIR/proc-macro-cannot-be-used.rs:29:18
    |
 LL |     fn inherent1(#[id] self, #[id] arg1: u8) {}
    |                  ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:30:30
+  --> $DIR/proc-macro-cannot-be-used.rs:29:30
    |
 LL |     fn inherent1(#[id] self, #[id] arg1: u8) {}
    |                              ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:33:18
+  --> $DIR/proc-macro-cannot-be-used.rs:32:18
    |
 LL |     fn inherent2(#[id] &self, #[id] arg1: u8) {}
    |                  ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:33:31
+  --> $DIR/proc-macro-cannot-be-used.rs:32:31
    |
 LL |     fn inherent2(#[id] &self, #[id] arg1: u8) {}
    |                               ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:36:22
+  --> $DIR/proc-macro-cannot-be-used.rs:35:22
    |
 LL |     fn inherent3<'a>(#[id] &'a mut self, #[id] arg1: u8) {}
    |                      ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:36:42
+  --> $DIR/proc-macro-cannot-be-used.rs:35:42
    |
 LL |     fn inherent3<'a>(#[id] &'a mut self, #[id] arg1: u8) {}
    |                                          ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:39:22
+  --> $DIR/proc-macro-cannot-be-used.rs:38:22
    |
 LL |     fn inherent4<'a>(#[id] self: Box<Self>, #[id] arg1: u8) {}
    |                      ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:39:45
+  --> $DIR/proc-macro-cannot-be-used.rs:38:45
    |
 LL |     fn inherent4<'a>(#[id] self: Box<Self>, #[id] arg1: u8) {}
    |                                             ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:45:15
+  --> $DIR/proc-macro-cannot-be-used.rs:44:15
    |
 LL |     fn trait1(#[id] self, #[id] arg1: u8);
    |               ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:45:27
+  --> $DIR/proc-macro-cannot-be-used.rs:44:27
    |
 LL |     fn trait1(#[id] self, #[id] arg1: u8);
    |                           ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:48:15
+  --> $DIR/proc-macro-cannot-be-used.rs:47:15
    |
 LL |     fn trait2(#[id] &self, #[id] arg1: u8);
    |               ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:48:28
+  --> $DIR/proc-macro-cannot-be-used.rs:47:28
    |
 LL |     fn trait2(#[id] &self, #[id] arg1: u8);
    |                            ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:51:19
+  --> $DIR/proc-macro-cannot-be-used.rs:50:19
    |
 LL |     fn trait3<'a>(#[id] &'a mut self, #[id] arg1: u8);
    |                   ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:51:39
+  --> $DIR/proc-macro-cannot-be-used.rs:50:39
    |
 LL |     fn trait3<'a>(#[id] &'a mut self, #[id] arg1: u8);
    |                                       ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:54:19
+  --> $DIR/proc-macro-cannot-be-used.rs:53:19
    |
 LL |     fn trait4<'a>(#[id] self: Box<Self>, #[id] arg1: u8, #[id] Vec<u8>);
    |                   ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:54:42
+  --> $DIR/proc-macro-cannot-be-used.rs:53:42
    |
 LL |     fn trait4<'a>(#[id] self: Box<Self>, #[id] arg1: u8, #[id] Vec<u8>);
    |                                          ^^^^^
 
 error: expected an inert attribute, found an attribute macro
-  --> $DIR/proc-macro-cannot-be-used.rs:54:58
+  --> $DIR/proc-macro-cannot-be-used.rs:53:58
    |
 LL |     fn trait4<'a>(#[id] self: Box<Self>, #[id] arg1: u8, #[id] Vec<u8>);
    |                                                          ^^^^^

From 144b8450735f61270cae223c1fd12e2f605c5b34 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Tue, 10 Sep 2019 13:48:30 +0200
Subject: [PATCH 02/11] Add long error explanation for E0312

---
 src/librustc/error_codes.rs | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/librustc/error_codes.rs b/src/librustc/error_codes.rs
index eee33846139e6..f6564f1fcd4c1 100644
--- a/src/librustc/error_codes.rs
+++ b/src/librustc/error_codes.rs
@@ -1347,6 +1347,39 @@ struct Foo<T: 'static> {
 ```
 "##,
 
+E0312: r##"
+Reference's lifetime of borrowed content doesn't match the expected lifetime.
+
+Erroneous code example:
+
+```compile_fail,E0312
+pub fn opt_str<'a>(maybestr: &'a Option<String>) -> &'static str {
+    if maybestr.is_none() {
+        "(none)"
+    } else {
+        let s: &'a str = maybestr.as_ref().unwrap();
+        s  // Invalid lifetime!
+    }
+}
+```
+
+To fix this error, either lessen the expected lifetime or find a way to not have
+to use this reference outside of its current scope (by running the code directly
+in the same block for example?):
+
+```
+// In this case, we can fix the issue by switching from "static" lifetime to 'a
+pub fn opt_str<'a>(maybestr: &'a Option<String>) -> &'a str {
+    if maybestr.is_none() {
+        "(none)"
+    } else {
+        let s: &'a str = maybestr.as_ref().unwrap();
+        s  // Ok!
+    }
+}
+```
+"##,
+
 E0317: r##"
 This error occurs when an `if` expression without an `else` block is used in a
 context where a type other than `()` is expected, for example a `let`
@@ -2202,7 +2235,6 @@ static X: u32 = 42;
 //  E0304, // expected signed integer constant
 //  E0305, // expected constant
     E0311, // thing may not live long enough
-    E0312, // lifetime of reference outlives lifetime of borrowed content
     E0313, // lifetime of borrowed pointer outlives lifetime of captured
            // variable
     E0314, // closure outlives stack frame

From cf6a1feda65525b947bfd33279c8b74c00f098c6 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Thu, 12 Sep 2019 13:25:42 +0200
Subject: [PATCH 03/11] update ui tests

---
 src/test/ui/issues/issue-10291.stderr                          | 1 +
 src/test/ui/issues/issue-52533.stderr                          | 1 +
 src/test/ui/lub-if.stderr                                      | 1 +
 src/test/ui/lub-match.stderr                                   | 1 +
 src/test/ui/nll/issue-52742.stderr                             | 1 +
 src/test/ui/nll/issue-55401.stderr                             | 1 +
 .../ui/nll/user-annotations/constant-in-expr-normalize.stderr  | 1 +
 .../nll/user-annotations/constant-in-expr-trait-item-1.stderr  | 1 +
 .../nll/user-annotations/constant-in-expr-trait-item-2.stderr  | 1 +
 src/test/ui/regions/regions-early-bound-error-method.stderr    | 1 +
 src/test/ui/regions/regions-early-bound-error.stderr           | 1 +
 src/test/ui/regions/regions-nested-fns.stderr                  | 1 +
 src/test/ui/regions/regions-static-bound.migrate.stderr        | 3 ++-
 ...ed-closures-infer-argument-types-two-region-pointers.stderr | 1 +
 src/test/ui/wf/wf-static-method.stderr                         | 3 ++-
 15 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/test/ui/issues/issue-10291.stderr b/src/test/ui/issues/issue-10291.stderr
index 5e63469da59f5..a836593e0da10 100644
--- a/src/test/ui/issues/issue-10291.stderr
+++ b/src/test/ui/issues/issue-10291.stderr
@@ -20,3 +20,4 @@ LL | fn test<'x>(x: &'x isize) {
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/issues/issue-52533.stderr b/src/test/ui/issues/issue-52533.stderr
index 1ed740c421e0f..586548002072e 100644
--- a/src/test/ui/issues/issue-52533.stderr
+++ b/src/test/ui/issues/issue-52533.stderr
@@ -17,3 +17,4 @@ LL |     foo(|a, b| b)
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/lub-if.stderr b/src/test/ui/lub-if.stderr
index bb772d4c6c695..26f756c91833b 100644
--- a/src/test/ui/lub-if.stderr
+++ b/src/test/ui/lub-if.stderr
@@ -26,3 +26,4 @@ LL | pub fn opt_str3<'a>(maybestr: &'a Option<String>) -> &'static str {
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/lub-match.stderr b/src/test/ui/lub-match.stderr
index 090af25143670..0cb0a23c6f2df 100644
--- a/src/test/ui/lub-match.stderr
+++ b/src/test/ui/lub-match.stderr
@@ -26,3 +26,4 @@ LL | pub fn opt_str3<'a>(maybestr: &'a Option<String>) -> &'static str {
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/nll/issue-52742.stderr b/src/test/ui/nll/issue-52742.stderr
index b982915800294..90a35177f4c3b 100644
--- a/src/test/ui/nll/issue-52742.stderr
+++ b/src/test/ui/nll/issue-52742.stderr
@@ -20,3 +20,4 @@ LL | |     }
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/nll/issue-55401.stderr b/src/test/ui/nll/issue-55401.stderr
index 50debc6386f6a..4ec16ba055a4c 100644
--- a/src/test/ui/nll/issue-55401.stderr
+++ b/src/test/ui/nll/issue-55401.stderr
@@ -13,3 +13,4 @@ LL | fn static_to_a_to_static_through_ref_in_tuple<'a>(x: &'a u32) -> &'static u
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/nll/user-annotations/constant-in-expr-normalize.stderr b/src/test/ui/nll/user-annotations/constant-in-expr-normalize.stderr
index f49d68458bea5..0a8ad4221c986 100644
--- a/src/test/ui/nll/user-annotations/constant-in-expr-normalize.stderr
+++ b/src/test/ui/nll/user-annotations/constant-in-expr-normalize.stderr
@@ -13,3 +13,4 @@ LL | fn foo<'a>(_: &'a u32) -> &'static u32 {
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-1.stderr b/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-1.stderr
index 451bcf41e42a9..d596aaf098f77 100644
--- a/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-1.stderr
+++ b/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-1.stderr
@@ -13,3 +13,4 @@ LL | fn foo<'a>(_: &'a u32) -> &'static u32 {
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-2.stderr b/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-2.stderr
index d129e55e1e6f6..80ff9a043d4d5 100644
--- a/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-2.stderr
+++ b/src/test/ui/nll/user-annotations/constant-in-expr-trait-item-2.stderr
@@ -13,3 +13,4 @@ LL | fn foo<'a, T: Foo<'a>>() -> &'static u32 {
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/regions/regions-early-bound-error-method.stderr b/src/test/ui/regions/regions-early-bound-error-method.stderr
index 2e5f55f8742cc..7b9f2c9503b2f 100644
--- a/src/test/ui/regions/regions-early-bound-error-method.stderr
+++ b/src/test/ui/regions/regions-early-bound-error-method.stderr
@@ -17,3 +17,4 @@ LL |     fn or<'b,G:GetRef<'b>>(&self, g2: G) -> &'a isize {
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/regions/regions-early-bound-error.stderr b/src/test/ui/regions/regions-early-bound-error.stderr
index bc52f4bef7eaa..a68355b78f54c 100644
--- a/src/test/ui/regions/regions-early-bound-error.stderr
+++ b/src/test/ui/regions/regions-early-bound-error.stderr
@@ -17,3 +17,4 @@ LL | fn get<'a,'b,G:GetRef<'a, isize>>(g1: G, b: &'b isize) -> &'b isize {
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/regions/regions-nested-fns.stderr b/src/test/ui/regions/regions-nested-fns.stderr
index 15c9c9ca4ddbb..904dee6998c9b 100644
--- a/src/test/ui/regions/regions-nested-fns.stderr
+++ b/src/test/ui/regions/regions-nested-fns.stderr
@@ -57,3 +57,4 @@ LL | fn nested<'x>(x: &'x isize) {
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/regions/regions-static-bound.migrate.stderr b/src/test/ui/regions/regions-static-bound.migrate.stderr
index fc8cca929d389..21ead8b768f47 100644
--- a/src/test/ui/regions/regions-static-bound.migrate.stderr
+++ b/src/test/ui/regions/regions-static-bound.migrate.stderr
@@ -30,4 +30,5 @@ LL |     static_id_indirect(&v);
 
 error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0621`.
+Some errors have detailed explanations: E0312, E0621.
+For more information about an error, try `rustc --explain E0312`.
diff --git a/src/test/ui/unboxed-closures/unboxed-closures-infer-argument-types-two-region-pointers.stderr b/src/test/ui/unboxed-closures/unboxed-closures-infer-argument-types-two-region-pointers.stderr
index 728efadf4196e..526055ba04b65 100644
--- a/src/test/ui/unboxed-closures/unboxed-closures-infer-argument-types-two-region-pointers.stderr
+++ b/src/test/ui/unboxed-closures/unboxed-closures-infer-argument-types-two-region-pointers.stderr
@@ -23,3 +23,4 @@ LL | |     });
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0312`.
diff --git a/src/test/ui/wf/wf-static-method.stderr b/src/test/ui/wf/wf-static-method.stderr
index f82526aa88ebf..3ec90f00448a9 100644
--- a/src/test/ui/wf/wf-static-method.stderr
+++ b/src/test/ui/wf/wf-static-method.stderr
@@ -105,4 +105,5 @@ LL |     <IndirectEvil>::static_evil(b)
 
 error: aborting due to 5 previous errors
 
-For more information about this error, try `rustc --explain E0478`.
+Some errors have detailed explanations: E0312, E0478.
+For more information about an error, try `rustc --explain E0312`.

From 194d357e03dcee73bfdb32a45175c97f4c3ce422 Mon Sep 17 00:00:00 2001
From: Charles Gleason <charles_gleason@alumni.brown.edu>
Date: Tue, 3 Sep 2019 18:42:58 -0400
Subject: [PATCH 04/11] Document `From` trait for `LhsExpr`

---
 src/libsyntax/parse/parser/expr.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/libsyntax/parse/parser/expr.rs b/src/libsyntax/parse/parser/expr.rs
index 5b9f0f1df6718..c38b134154d62 100644
--- a/src/libsyntax/parse/parser/expr.rs
+++ b/src/libsyntax/parse/parser/expr.rs
@@ -66,6 +66,10 @@ pub(super) enum LhsExpr {
 }
 
 impl From<Option<ThinVec<Attribute>>> for LhsExpr {
+    /// Converts `Some(attrs)` into `LhsExpr::AttributesParsed(attrs)`
+    /// and `None` into `LhsExpr::NotYetParsed`.
+    ///
+    /// This conversion does not allocate.
     fn from(o: Option<ThinVec<Attribute>>) -> Self {
         if let Some(attrs) = o {
             LhsExpr::AttributesParsed(attrs)
@@ -76,6 +80,9 @@ impl From<Option<ThinVec<Attribute>>> for LhsExpr {
 }
 
 impl From<P<Expr>> for LhsExpr {
+    /// Converts the `expr: P<Expr>` into `LhsExpr::AlreadyParsed(expr)`.
+    ///
+    /// This conversion does not allocate.
     fn from(expr: P<Expr>) -> Self {
         LhsExpr::AlreadyParsed(expr)
     }

From 1ab5593f951c07a6f0ed05fbbfe8f262863158a0 Mon Sep 17 00:00:00 2001
From: gaolei <gaolei@zhihu.com>
Date: Thu, 19 Sep 2019 15:13:40 +0800
Subject: [PATCH 05/11] factor out pluralisation remains after #64280

---
 src/librustc/lint/builtin.rs                |  4 ++--
 src/librustc/middle/resolve_lifetime.rs     |  4 ++--
 src/librustc/traits/error_reporting.rs      |  4 ++--
 src/librustc/ty/error.rs                    |  2 +-
 src/librustc_lint/unused.rs                 | 22 ++++++++++++++-------
 src/librustc_resolve/check_unused.rs        |  4 +++-
 src/librustc_resolve/resolve_imports.rs     |  4 ++--
 src/librustc_typeck/astconv.rs              |  2 +-
 src/librustc_typeck/check/expr.rs           |  4 ++--
 src/librustc_typeck/check/method/suggest.rs |  4 ++--
 src/librustc_typeck/check/mod.rs            |  4 ++--
 src/librustc_typeck/check/pat.rs            | 14 ++++++-------
 src/libsyntax/ext/tt/transcribe.rs          |  5 +++--
 src/libsyntax/parse/diagnostics.rs          |  8 ++++----
 src/libsyntax/parse/parser/path.rs          |  7 +++----
 src/libsyntax/parse/parser/ty.rs            |  6 +++---
 src/libsyntax_ext/format.rs                 |  3 ++-
 17 files changed, 56 insertions(+), 45 deletions(-)

diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs
index dd290572d7bb7..5906a6388a8bd 100644
--- a/src/librustc/lint/builtin.rs
+++ b/src/librustc/lint/builtin.rs
@@ -7,7 +7,7 @@
 use crate::lint::{LintPass, LateLintPass, LintArray};
 use crate::middle::stability;
 use crate::session::Session;
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use syntax::ast;
 use syntax::source_map::Span;
 use syntax::symbol::Symbol;
@@ -524,7 +524,7 @@ pub(crate) fn add_elided_lifetime_in_path_suggestion(
     };
     db.span_suggestion(
         replace_span,
-        &format!("indicate the anonymous lifetime{}", if n >= 2 { "s" } else { "" }),
+        &format!("indicate the anonymous lifetime{}", pluralise!(n)),
         suggestion,
         Applicability::MachineApplicable
     );
diff --git a/src/librustc/middle/resolve_lifetime.rs b/src/librustc/middle/resolve_lifetime.rs
index 8836a632a7ca8..d833a34385b2d 100644
--- a/src/librustc/middle/resolve_lifetime.rs
+++ b/src/librustc/middle/resolve_lifetime.rs
@@ -17,7 +17,7 @@ use crate::ty::{self, DefIdTree, GenericParamDefKind, TyCtxt};
 use crate::rustc::lint;
 use crate::session::Session;
 use crate::util::nodemap::{DefIdMap, FxHashMap, FxHashSet, HirIdMap, HirIdSet};
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use rustc_macros::HashStable;
 use std::borrow::Cow;
 use std::cell::Cell;
@@ -3047,7 +3047,7 @@ pub fn report_missing_lifetime_specifiers(
         span,
         E0106,
         "missing lifetime specifier{}",
-        if count > 1 { "s" } else { "" }
+        pluralise!(count)
     )
 }
 
diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs
index 03cc00d87e3cd..0b06ec0703811 100644
--- a/src/librustc/traits/error_reporting.rs
+++ b/src/librustc/traits/error_reporting.rs
@@ -33,7 +33,7 @@ use crate::ty::subst::Subst;
 use crate::ty::SubtypePredicate;
 use crate::util::nodemap::{FxHashMap, FxHashSet};
 
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use std::fmt;
 use syntax::ast;
 use syntax::symbol::{sym, kw};
@@ -1186,7 +1186,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                 _ => format!("{} {}argument{}",
                              arg_length,
                              if distinct && arg_length > 1 { "distinct " } else { "" },
-                             if arg_length == 1 { "" } else { "s" }),
+                             pluralise!(arg_length))
             }
         };
 
diff --git a/src/librustc/ty/error.rs b/src/librustc/ty/error.rs
index 62910ec320494..5409cbc4129f0 100644
--- a/src/librustc/ty/error.rs
+++ b/src/librustc/ty/error.rs
@@ -196,7 +196,7 @@ impl<'tcx> ty::TyS<'tcx> {
                 let n = tcx.lift_to_global(&n).unwrap();
                 match n.try_eval_usize(tcx, ty::ParamEnv::empty()) {
                     Some(n) => {
-                        format!("array of {} element{}", n, if n != 1 { "s" } else { "" }).into()
+                        format!("array of {} element{}", n, pluralise!(n)).into()
                     }
                     None => "array".into(),
                 }
diff --git a/src/librustc_lint/unused.rs b/src/librustc_lint/unused.rs
index c3975098351af..2d4af2f606a2c 100644
--- a/src/librustc_lint/unused.rs
+++ b/src/librustc_lint/unused.rs
@@ -9,7 +9,7 @@ use lint::{LintPass, EarlyLintPass, LateLintPass};
 
 use syntax::ast;
 use syntax::attr;
-use syntax::errors::Applicability;
+use syntax::errors::{Applicability, pluralise};
 use syntax::feature_gate::{AttributeType, BuiltinAttribute, BUILTIN_ATTRIBUTE_MAP};
 use syntax::print::pprust;
 use syntax::symbol::{kw, sym};
@@ -48,7 +48,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
         }
 
         let ty = cx.tables.expr_ty(&expr);
-        let type_permits_lack_of_use = check_must_use_ty(cx, ty, &expr, s.span, "", "", false);
+        let type_permits_lack_of_use = check_must_use_ty(cx, ty, &expr, s.span, "", "", 1);
 
         let mut fn_warned = false;
         let mut op_warned = false;
@@ -135,7 +135,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
             span: Span,
             descr_pre: &str,
             descr_post: &str,
-            plural: bool,
+            plural_len: usize,
         ) -> bool {
             if ty.is_unit() || cx.tcx.is_ty_uninhabited_from(
                 cx.tcx.hir().get_module_parent(expr.hir_id), ty)
@@ -143,13 +143,13 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
                 return true;
             }
 
-            let plural_suffix = if plural { "s" } else { "" };
+            let plural_suffix = pluralise!(plural_len);
 
             match ty.sty {
                 ty::Adt(..) if ty.is_box() => {
                     let boxed_ty = ty.boxed_ty();
                     let descr_pre = &format!("{}boxed ", descr_pre);
-                    check_must_use_ty(cx, boxed_ty, expr, span, descr_pre, descr_post, plural)
+                    check_must_use_ty(cx, boxed_ty, expr, span, descr_pre, descr_post, plural_len)
                 }
                 ty::Adt(def, _) => {
                     check_must_use_def(cx, def.did, span, descr_pre, descr_post)
@@ -202,7 +202,15 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
                     for (i, ty) in tys.iter().map(|k| k.expect_ty()).enumerate() {
                         let descr_post = &format!(" in tuple element {}", i);
                         let span = *spans.get(i).unwrap_or(&span);
-                        if check_must_use_ty(cx, ty, expr, span, descr_pre, descr_post, plural) {
+                        if check_must_use_ty(
+                            cx,
+                            ty,
+                            expr,
+                            span,
+                            descr_pre,
+                            descr_post,
+                            plural_len
+                        ) {
                             has_emitted = true;
                         }
                     }
@@ -216,7 +224,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedResults {
                             descr_pre,
                             plural_suffix,
                         );
-                        check_must_use_ty(cx, ty, expr, span, descr_pre, descr_post, true)
+                        check_must_use_ty(cx, ty, expr, span, descr_pre, descr_post, n as usize + 1)
                     }
                     // Otherwise, we don't lint, to avoid false positives.
                     _ => false,
diff --git a/src/librustc_resolve/check_unused.rs b/src/librustc_resolve/check_unused.rs
index 96d44b4b4c0dc..0d85be83e12e0 100644
--- a/src/librustc_resolve/check_unused.rs
+++ b/src/librustc_resolve/check_unused.rs
@@ -26,6 +26,8 @@
 use crate::Resolver;
 use crate::resolve_imports::ImportDirectiveSubclass;
 
+use errors::pluralise;
+
 use rustc::util::nodemap::NodeMap;
 use rustc::{lint, ty};
 use rustc_data_structures::fx::FxHashSet;
@@ -295,7 +297,7 @@ impl Resolver<'_> {
                 }).collect::<Vec<String>>();
             span_snippets.sort();
             let msg = format!("unused import{}{}",
-                            if len > 1 { "s" } else { "" },
+                            pluralise!(len),
                             if !span_snippets.is_empty() {
                                 format!(": {}", span_snippets.join(", "))
                             } else {
diff --git a/src/librustc_resolve/resolve_imports.rs b/src/librustc_resolve/resolve_imports.rs
index e77e8290f1faa..360343169bc3d 100644
--- a/src/librustc_resolve/resolve_imports.rs
+++ b/src/librustc_resolve/resolve_imports.rs
@@ -11,7 +11,7 @@ use crate::{Resolver, ResolutionError, Segment, ModuleKind};
 use crate::{names_to_string, module_to_string};
 use crate::diagnostics::Suggestion;
 
-use errors::Applicability;
+use errors::{Applicability, pluralise};
 
 use rustc_data_structures::ptr_key::PtrKey;
 use rustc::ty;
@@ -728,7 +728,7 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
 
             let msg = format!(
                 "unresolved import{} {}",
-                if paths.len() > 1 { "s" } else { "" },
+                pluralise!(paths.len()),
                 paths.join(", "),
             );
 
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 09e6b76900396..718d12484f741 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -1346,7 +1346,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 span,
                 E0191,
                 "the value of the associated type{} {} must be specified",
-                if associated_types.len() == 1 { "" } else { "s" },
+                pluralise!(associated_types.len()),
                 names,
             );
             let (suggest, potential_assoc_types_spans) =
diff --git a/src/librustc_typeck/check/expr.rs b/src/librustc_typeck/check/expr.rs
index 56bd903040ab4..ef3f40dfdd987 100644
--- a/src/librustc_typeck/check/expr.rs
+++ b/src/librustc_typeck/check/expr.rs
@@ -17,7 +17,7 @@ use crate::util::common::ErrorReported;
 use crate::util::nodemap::FxHashMap;
 use crate::astconv::AstConv as _;
 
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use syntax::ast;
 use syntax::symbol::{Symbol, kw, sym};
 use syntax::source_map::Span;
@@ -1178,7 +1178,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
             struct_span_err!(tcx.sess, span, E0063,
                              "missing field{} {}{} in initializer of `{}`",
-                             if remaining_fields.len() == 1 { "" } else { "s" },
+                             pluralise!(remaining_fields.len()),
                              remaining_fields_names,
                              truncated_fields_error,
                              adt_ty)
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index 3e45b1e98d4ec..74e4f28255b16 100644
--- a/src/librustc_typeck/check/method/suggest.rs
+++ b/src/librustc_typeck/check/method/suggest.rs
@@ -5,7 +5,7 @@ use crate::check::FnCtxt;
 use crate::middle::lang_items::FnOnceTraitLangItem;
 use crate::namespace::Namespace;
 use crate::util::nodemap::FxHashSet;
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use rustc::hir::{self, ExprKind, Node, QPath};
 use rustc::hir::def::{Res, DefKind};
 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
@@ -560,7 +560,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     let help = format!("{an}other candidate{s} {were} found in the following \
                                         trait{s}, perhaps add a `use` for {one_of_them}:",
                                     an = if candidates.len() == 1 {"an" } else { "" },
-                                    s = if candidates.len() == 1 { "" } else { "s" },
+                                    s = pluralise!(candidates.len()),
                                     were = if candidates.len() == 1 { "was" } else { "were" },
                                     one_of_them = if candidates.len() == 1 {
                                         "it"
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 1197160fa9501..bd6586aa0777e 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -88,7 +88,7 @@ pub mod intrinsic;
 mod op;
 
 use crate::astconv::{AstConv, PathSeg};
-use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
+use errors::{Applicability, DiagnosticBuilder, DiagnosticId, pluralise};
 use rustc::hir::{self, ExprKind, GenericArg, ItemKind, Node, PatKind, QPath};
 use rustc::hir::def::{CtorOf, Res, DefKind};
 use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE};
@@ -4843,5 +4843,5 @@ fn fatally_break_rust(sess: &Session) {
 }
 
 fn potentially_plural_count(count: usize, word: &str) -> String {
-    format!("{} {}{}", count, word, if count == 1 { "" } else { "s" })
+    format!("{} {}{}", count, word, pluralise!(count))
 }
diff --git a/src/librustc_typeck/check/pat.rs b/src/librustc_typeck/check/pat.rs
index 8502b89de1469..d93a4052cd393 100644
--- a/src/librustc_typeck/check/pat.rs
+++ b/src/librustc_typeck/check/pat.rs
@@ -1,6 +1,6 @@
 use crate::check::FnCtxt;
 use crate::util::nodemap::FxHashMap;
-use errors::{Applicability, DiagnosticBuilder};
+use errors::{Applicability, DiagnosticBuilder, pluralise};
 use rustc::hir::{self, PatKind, Pat, HirId};
 use rustc::hir::def::{Res, DefKind, CtorKind};
 use rustc::hir::pat_util::EnumerateAndAdjustIterator;
@@ -684,8 +684,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     }
 
     fn e0023(&self, pat_span: Span, res: Res, subpats: &'tcx [P<Pat>], fields: &[ty::FieldDef]) {
-        let subpats_ending = if subpats.len() == 1 { "" } else { "s" };
-        let fields_ending = if fields.len() == 1 { "" } else { "s" };
+        let subpats_ending = pluralise!(subpats.len());
+        let fields_ending = pluralise!(fields.len());
         let res_span = self.tcx.def_span(res.def_id());
         struct_span_err!(
             self.tcx.sess,
@@ -1103,10 +1103,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             E0527,
             "pattern requires {} element{} but array has {}",
             min_len,
-            if min_len != 1 { "s" } else { "" },
+            pluralise!(min_len),
             size,
         )
-        .span_label(span, format!("expected {} element{}", size, if size != 1 { "s" } else { "" }))
+        .span_label(span, format!("expected {} element{}", size, pluralise!(size)))
         .emit();
     }
 
@@ -1117,14 +1117,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             E0528,
             "pattern requires at least {} element{} but array has {}",
             min_len,
-            if min_len != 1 { "s" } else { "" },
+            pluralise!(min_len),
             size,
         ).span_label(
             span,
             format!(
                 "pattern cannot match array of {} element{}",
                 size,
-                if size != 1 { "s" } else { "" },
+                pluralise!(size),
             ),
         ).emit();
     }
diff --git a/src/libsyntax/ext/tt/transcribe.rs b/src/libsyntax/ext/tt/transcribe.rs
index 23735727fe8cf..f9c07e3a2e4ff 100644
--- a/src/libsyntax/ext/tt/transcribe.rs
+++ b/src/libsyntax/ext/tt/transcribe.rs
@@ -8,6 +8,7 @@ use crate::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndJoint};
 
 use smallvec::{smallvec, SmallVec};
 
+use errors::pluralise;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
 use syntax_pos::hygiene::{ExpnId, Transparency};
@@ -348,10 +349,10 @@ impl LockstepIterSize {
                         "meta-variable `{}` repeats {} time{}, but `{}` repeats {} time{}",
                         l_id,
                         l_len,
-                        if l_len != 1 { "s" } else { "" },
+                        pluralise!(l_len),
                         r_id,
                         r_len,
-                        if r_len != 1 { "s" } else { "" },
+                        pluralise!(r_len),
                     );
                     LockstepIterSize::Contradiction(msg)
                 }
diff --git a/src/libsyntax/parse/diagnostics.rs b/src/libsyntax/parse/diagnostics.rs
index b74f2492c351f..2d7f4f71ca4ee 100644
--- a/src/libsyntax/parse/diagnostics.rs
+++ b/src/libsyntax/parse/diagnostics.rs
@@ -11,7 +11,7 @@ use crate::ptr::P;
 use crate::symbol::{kw, sym};
 use crate::ThinVec;
 use crate::util::parser::AssocOp;
-use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
+use errors::{Applicability, DiagnosticBuilder, DiagnosticId, pluralise};
 use rustc_data_structures::fx::FxHashSet;
 use syntax_pos::{Span, DUMMY_SP, MultiSpan, SpanSnippetError};
 use log::{debug, trace};
@@ -532,15 +532,15 @@ impl<'a> Parser<'a> {
             self.eat_to_tokens(&[&end]);
             let span = lo.until(self.token.span);
 
-            let plural = number_of_gt > 1 || number_of_shr >= 1;
+            let total_num_of_gt = number_of_gt + number_of_shr * 2;
             self.diagnostic()
                 .struct_span_err(
                     span,
-                    &format!("unmatched angle bracket{}", if plural { "s" } else { "" }),
+                    &format!("unmatched angle bracket{}", pluralise!(total_num_of_gt)),
                 )
                 .span_suggestion(
                     span,
-                    &format!("remove extra angle bracket{}", if plural { "s" } else { "" }),
+                    &format!("remove extra angle bracket{}", pluralise!(total_num_of_gt)),
                     String::new(),
                     Applicability::MachineApplicable,
                 )
diff --git a/src/libsyntax/parse/parser/path.rs b/src/libsyntax/parse/parser/path.rs
index d4b13cc2e0121..dcd3c64801742 100644
--- a/src/libsyntax/parse/parser/path.rs
+++ b/src/libsyntax/parse/parser/path.rs
@@ -9,7 +9,7 @@ use crate::symbol::kw;
 
 use std::mem;
 use log::debug;
-use errors::{Applicability};
+use errors::{Applicability, pluralise};
 
 /// Specifies how to parse a path.
 #[derive(Copy, Clone, PartialEq)]
@@ -347,20 +347,19 @@ impl<'a> Parser<'a> {
                 let span = lo.with_hi(
                     lo.lo() + BytePos(snapshot.unmatched_angle_bracket_count)
                 );
-                let plural = snapshot.unmatched_angle_bracket_count > 1;
                 self.diagnostic()
                     .struct_span_err(
                         span,
                         &format!(
                             "unmatched angle bracket{}",
-                            if plural { "s" } else { "" }
+                            pluralise!(snapshot.unmatched_angle_bracket_count)
                         ),
                     )
                     .span_suggestion(
                         span,
                         &format!(
                             "remove extra angle bracket{}",
-                            if plural { "s" } else { "" }
+                            pluralise!(snapshot.unmatched_angle_bracket_count)
                         ),
                         String::new(),
                         Applicability::MachineApplicable,
diff --git a/src/libsyntax/parse/parser/ty.rs b/src/libsyntax/parse/parser/ty.rs
index 465e31ac57e64..5697edd8e4867 100644
--- a/src/libsyntax/parse/parser/ty.rs
+++ b/src/libsyntax/parse/parser/ty.rs
@@ -11,7 +11,7 @@ use crate::symbol::{kw};
 
 use rustc_target::spec::abi::Abi;
 
-use errors::{Applicability};
+use errors::{Applicability, pluralise};
 
 /// Returns `true` if `IDENT t` can start a type -- `IDENT::a::b`, `IDENT<u8, u8>`,
 /// `IDENT<<u8 as Trait>::AssocTy>`.
@@ -397,7 +397,7 @@ impl<'a> Parser<'a> {
         }
 
         if !negative_bounds.is_empty() || was_negative {
-            let plural = negative_bounds.len() > 1;
+            let negative_bounds_len = negative_bounds.len();
             let last_span = negative_bounds.last().map(|sp| *sp);
             let mut err = self.struct_span_err(
                 negative_bounds,
@@ -420,7 +420,7 @@ impl<'a> Parser<'a> {
                 }
                 err.span_suggestion_hidden(
                     bound_list,
-                    &format!("remove the trait bound{}", if plural { "s" } else { "" }),
+                    &format!("remove the trait bound{}", pluralise!(negative_bounds_len)),
                     new_bound_list,
                     Applicability::MachineApplicable,
                 );
diff --git a/src/libsyntax_ext/format.rs b/src/libsyntax_ext/format.rs
index 46c7cbb83de90..26455df17b896 100644
--- a/src/libsyntax_ext/format.rs
+++ b/src/libsyntax_ext/format.rs
@@ -5,6 +5,7 @@ use fmt_macros as parse;
 
 use errors::DiagnosticBuilder;
 use errors::Applicability;
+use errors::pluralise;
 
 use syntax::ast;
 use syntax::ext::base::{self, *};
@@ -299,7 +300,7 @@ impl<'a, 'b> Context<'a, 'b> {
                 &format!(
                     "{} positional argument{} in format string, but {}",
                     count,
-                    if count != 1 { "s" } else { "" },
+                    pluralise!(count),
                     self.describe_num_args(),
                 ),
             );

From 3db2c13d893865e8e6929d5259bbac7d89a7ba06 Mon Sep 17 00:00:00 2001
From: Erin Power <xampprocky@gmail.com>
Date: Thu, 19 Sep 2019 21:53:40 +0200
Subject: [PATCH 06/11] Add Compatibility Notes to RELEASES.md for 1.38.0

---
 RELEASES.md | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/RELEASES.md b/RELEASES.md
index d634feba33ac5..ecf49278f4b52 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -68,6 +68,13 @@ Misc
 - [`rustc` will now warn about some incorrect uses of
   `mem::{uninitialized, zeroed}` that are known to cause undefined behaviour.][63346]
 
+Compatibility Notes
+-------------------
+- Unfortunately the [`x86_64-unknown-uefi` platform can not be built][62785]
+  with rustc 1.39.0.
+- The [`armv7-unknown-linux-gnueabihf` platform is also known to have
+  issues][62896] for certain crates such as libc.
+
 [60260]: https://github.com/rust-lang/rust/pull/60260/
 [61457]: https://github.com/rust-lang/rust/pull/61457/
 [61491]: https://github.com/rust-lang/rust/pull/61491/
@@ -79,7 +86,9 @@ Misc
 [62735]: https://github.com/rust-lang/rust/pull/62735/
 [62766]: https://github.com/rust-lang/rust/pull/62766/
 [62784]: https://github.com/rust-lang/rust/pull/62784/
+[62785]: https://github.com/rust-lang/rust/issues/62785/
 [62814]: https://github.com/rust-lang/rust/pull/62814/
+[62896]: https://github.com/rust-lang/rust/issues/62896/
 [63000]: https://github.com/rust-lang/rust/pull/63000/
 [63056]: https://github.com/rust-lang/rust/pull/63056/
 [63107]: https://github.com/rust-lang/rust/pull/63107/

From c3140bae633b265657c0094f6df6edf630d1d917 Mon Sep 17 00:00:00 2001
From: guanqun <guanqun.lu@gmail.com>
Date: Sat, 21 Sep 2019 00:22:43 +0800
Subject: [PATCH 07/11] remove the extra comma after the match arm

This would follow the same coding style as all the other match arms in this file.
---
 src/librustc_resolve/late/diagnostics.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/librustc_resolve/late/diagnostics.rs b/src/librustc_resolve/late/diagnostics.rs
index 0c86d8494fde8..df8bd3fa75e14 100644
--- a/src/librustc_resolve/late/diagnostics.rs
+++ b/src/librustc_resolve/late/diagnostics.rs
@@ -424,7 +424,7 @@ impl<'a> LateResolutionVisitor<'a, '_> {
                 } else {
                     err.note("did you mean to use one of the enum's variants?");
                 }
-            },
+            }
             (Res::Def(DefKind::Struct, def_id), _) if ns == ValueNS => {
                 if let Some((ctor_def, ctor_vis))
                         = self.r.struct_constructors.get(&def_id).cloned() {

From 491a0c6902b4ad86bdf7b1b0fdd2fc7d6d12a026 Mon Sep 17 00:00:00 2001
From: Baoshan Pang <baoshan.pang@windriver.com>
Date: Fri, 20 Sep 2019 13:25:57 -0700
Subject: [PATCH 08/11] No home directory on vxWorks

---
 src/libstd/sys/vxworks/os.rs | 23 +----------------------
 1 file changed, 1 insertion(+), 22 deletions(-)

diff --git a/src/libstd/sys/vxworks/os.rs b/src/libstd/sys/vxworks/os.rs
index 5dc35a6176bce..f4798da1876cf 100644
--- a/src/libstd/sys/vxworks/os.rs
+++ b/src/libstd/sys/vxworks/os.rs
@@ -287,28 +287,7 @@ pub fn temp_dir() -> PathBuf {
 }
 
 pub fn home_dir() -> Option<PathBuf> {
-    return crate::env::var_os("HOME").or_else(|| unsafe {
-        fallback()
-    }).map(PathBuf::from);
-
-    unsafe fn fallback() -> Option<OsString> {
-        let amt = match libc::sysconf(libc::_SC_GETPW_R_SIZE_MAX) {
-            n if n < 0 => 512 as usize,
-            n => n as usize,
-        };
-        let mut buf = Vec::with_capacity(amt);
-        let mut passwd: libc::passwd = mem::zeroed();
-        let mut result = ptr::null_mut();
-        match libc::getpwuid_r(libc::getuid(), &mut passwd, buf.as_mut_ptr(),
-                                buf.capacity(), &mut result) {
-            0 if !result.is_null() => {
-                let ptr = passwd.pw_dir as *const _;
-                let bytes = CStr::from_ptr(ptr).to_bytes().to_vec();
-                Some(OsStringExt::from_vec(bytes))
-            },
-            _ => None,
-        }
-    }
+    None
 }
 
 pub fn exit(code: i32) -> ! {

From 9f374da46781cfe2d297636fe97b2fd9647cb1d9 Mon Sep 17 00:00:00 2001
From: Josh Stone <jistone@redhat.com>
Date: Fri, 20 Sep 2019 15:39:34 -0700
Subject: [PATCH 09/11] Exempt extern "Rust" from improper_ctypes

It should be fine for Rust ABIs to involve any Rust type.
---
 src/liballoc/alloc.rs             |  2 +-
 src/libcore/panicking.rs          |  2 +-
 src/librustc_lint/types.rs        |  4 +++-
 src/test/ui/issues/issue-64593.rs | 12 ++++++++++++
 4 files changed, 17 insertions(+), 3 deletions(-)
 create mode 100644 src/test/ui/issues/issue-64593.rs

diff --git a/src/liballoc/alloc.rs b/src/liballoc/alloc.rs
index dc7fd1adc2958..a39fcd5ad4c58 100644
--- a/src/liballoc/alloc.rs
+++ b/src/liballoc/alloc.rs
@@ -240,7 +240,7 @@ pub(crate) unsafe fn box_free<T: ?Sized>(ptr: Unique<T>) {
 #[stable(feature = "global_alloc", since = "1.28.0")]
 #[rustc_allocator_nounwind]
 pub fn handle_alloc_error(layout: Layout) -> ! {
-    #[allow(improper_ctypes)]
+    #[cfg_attr(bootstrap, allow(improper_ctypes))]
     extern "Rust" {
         #[lang = "oom"]
         fn oom_impl(layout: Layout) -> !;
diff --git a/src/libcore/panicking.rs b/src/libcore/panicking.rs
index 15b7d69c58d24..3d2bc24bf24a5 100644
--- a/src/libcore/panicking.rs
+++ b/src/libcore/panicking.rs
@@ -71,7 +71,7 @@ pub fn panic_fmt(fmt: fmt::Arguments<'_>, file_line_col: &(&'static str, u32, u3
     }
 
     // NOTE This function never crosses the FFI boundary; it's a Rust-to-Rust call
-    #[allow(improper_ctypes)] // PanicInfo contains a trait object which is not FFI safe
+    #[cfg_attr(boostrap_stdarch_ignore_this, allow(improper_ctypes))]
     extern "Rust" {
         #[lang = "panic_impl"]
         fn panic_impl(pi: &PanicInfo<'_>) -> !;
diff --git a/src/librustc_lint/types.rs b/src/librustc_lint/types.rs
index 3b8c06ba154c6..40261f6d13739 100644
--- a/src/librustc_lint/types.rs
+++ b/src/librustc_lint/types.rs
@@ -975,7 +975,9 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImproperCTypes {
     fn check_foreign_item(&mut self, cx: &LateContext<'_, '_>, it: &hir::ForeignItem) {
         let mut vis = ImproperCTypesVisitor { cx };
         let abi = cx.tcx.hir().get_foreign_abi(it.hir_id);
-        if abi != Abi::RustIntrinsic && abi != Abi::PlatformIntrinsic {
+        if let Abi::Rust | Abi::RustCall | Abi::RustIntrinsic | Abi::PlatformIntrinsic = abi {
+            // Don't worry about types in internal ABIs.
+        } else {
             match it.node {
                 hir::ForeignItemKind::Fn(ref decl, _, _) => {
                     vis.check_foreign_fn(it.hir_id, decl);
diff --git a/src/test/ui/issues/issue-64593.rs b/src/test/ui/issues/issue-64593.rs
new file mode 100644
index 0000000000000..9e787f638a998
--- /dev/null
+++ b/src/test/ui/issues/issue-64593.rs
@@ -0,0 +1,12 @@
+// check-pass
+#![deny(improper_ctypes)]
+
+pub struct Error(std::num::NonZeroU32);
+
+extern "Rust" {
+    fn foo(dest: &mut [u8]) -> Result<(), Error>;
+}
+
+fn main() {
+    let _ = unsafe { foo(&mut []) };
+}

From b956ae38e16a8f04b31d5cf5788f1d357617efbc Mon Sep 17 00:00:00 2001
From: Baoshan Pang <baoshan.pang@windriver.com>
Date: Fri, 20 Sep 2019 15:47:13 -0700
Subject: [PATCH 10/11] rust stat should call libc stat

---
 src/libstd/sys/vxworks/fs.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/libstd/sys/vxworks/fs.rs b/src/libstd/sys/vxworks/fs.rs
index d537d2258fda7..51fdb1c0e55ec 100644
--- a/src/libstd/sys/vxworks/fs.rs
+++ b/src/libstd/sys/vxworks/fs.rs
@@ -529,7 +529,7 @@ pub fn stat(p: &Path) -> io::Result<FileAttr> {
     let p = cstr(p)?;
     let mut stat: stat64 = unsafe { mem::zeroed() };
     cvt(unsafe {
-        libc::lstat(p.as_ptr(), &mut stat as *mut _ as *mut _)
+        libc::stat(p.as_ptr(), &mut stat as *mut _ as *mut _)
     })?;
     Ok(FileAttr { stat })
 }

From c3f72d1c098a61f26271021460b5ae420ff28ae8 Mon Sep 17 00:00:00 2001
From: Josh Stone <jistone@redhat.com>
Date: Fri, 20 Sep 2019 16:06:32 -0700
Subject: [PATCH 11/11] Fix the span used to suggest avoiding for-loop moves

It was using the snippet from the "use" span, which often renders the
same, but with closures that snippet is on the start of the closure
where the value is captured. We should be using the snippet from the
span where it was moved into the `for` loop, which is `move_span`.
---
 .../borrow_check/conflict_errors.rs            |  3 ++-
 src/test/ui/issues/issue-64559.rs              |  6 ++++++
 src/test/ui/issues/issue-64559.stderr          | 18 ++++++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 src/test/ui/issues/issue-64559.rs
 create mode 100644 src/test/ui/issues/issue-64559.stderr

diff --git a/src/librustc_mir/borrow_check/conflict_errors.rs b/src/librustc_mir/borrow_check/conflict_errors.rs
index 81359c6a46e99..599a0ad0d0c52 100644
--- a/src/librustc_mir/borrow_check/conflict_errors.rs
+++ b/src/librustc_mir/borrow_check/conflict_errors.rs
@@ -180,7 +180,8 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                     );
                 }
                 if Some(DesugaringKind::ForLoop) == move_span.desugaring_kind() {
-                    if let Ok(snippet) = self.infcx.tcx.sess.source_map().span_to_snippet(span) {
+                    let sess = self.infcx.tcx.sess;
+                    if let Ok(snippet) = sess.source_map().span_to_snippet(move_span) {
                         err.span_suggestion(
                             move_span,
                             "consider borrowing to avoid moving into the for loop",
diff --git a/src/test/ui/issues/issue-64559.rs b/src/test/ui/issues/issue-64559.rs
new file mode 100644
index 0000000000000..71e054b5d9876
--- /dev/null
+++ b/src/test/ui/issues/issue-64559.rs
@@ -0,0 +1,6 @@
+fn main() {
+    let orig = vec![true];
+    for _val in orig {}
+    let _closure = || orig;
+    //~^ ERROR use of moved value: `orig`
+}
diff --git a/src/test/ui/issues/issue-64559.stderr b/src/test/ui/issues/issue-64559.stderr
new file mode 100644
index 0000000000000..3c685dc8d089a
--- /dev/null
+++ b/src/test/ui/issues/issue-64559.stderr
@@ -0,0 +1,18 @@
+error[E0382]: use of moved value: `orig`
+  --> $DIR/issue-64559.rs:4:20
+   |
+LL |     let orig = vec![true];
+   |         ---- move occurs because `orig` has type `std::vec::Vec<bool>`, which does not implement the `Copy` trait
+LL |     for _val in orig {}
+   |                 ----
+   |                 |
+   |                 value moved here
+   |                 help: consider borrowing to avoid moving into the for loop: `&orig`
+LL |     let _closure = || orig;
+   |                    ^^ ---- use occurs due to use in closure
+   |                    |
+   |                    value used here after move
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0382`.