Merge branch 'master' into issue-69276

10 files changed, 96 insertions, 15 deletions

diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs
index 6467561e509..c0b16c22e4d 100644
--- a/src/librustc_error_codes/error_codes.rs
+++ b/src/librustc_error_codes/error_codes.rs
@@ -120,6 +120,7 @@ E0223: include_str!("./error_codes/E0223.md"),
 E0224: include_str!("./error_codes/E0224.md"),
 E0225: include_str!("./error_codes/E0225.md"),
 E0226: include_str!("./error_codes/E0226.md"),
+E0228: include_str!("./error_codes/E0228.md"),
 E0229: include_str!("./error_codes/E0229.md"),
 E0230: include_str!("./error_codes/E0230.md"),
 E0231: include_str!("./error_codes/E0231.md"),
@@ -435,6 +436,7 @@ E0750: include_str!("./error_codes/E0750.md"),
 E0751: include_str!("./error_codes/E0751.md"),
 E0752: include_str!("./error_codes/E0752.md"),
 E0753: include_str!("./error_codes/E0753.md"),
+E0754: include_str!("./error_codes/E0754.md"),
 E0755: include_str!("./error_codes/E0755.md"),
 ;
 //  E0006, // merged with E0005
@@ -483,7 +485,6 @@ E0755: include_str!("./error_codes/E0755.md"),
 //  E0218, // no associated type defined
 //  E0219, // associated type defined in higher-ranked supertrait
     E0227, // ambiguous lifetime bound, explicit lifetime bound required
-    E0228, // explicit lifetime bound required
 //  E0233,
 //  E0234,
 //  E0235, // structure constructor specifies a structure of type but
diff --git a/src/librustc_error_codes/error_codes/E0228.md b/src/librustc_error_codes/error_codes/E0228.md
new file mode 100644
index 00000000000..3443a5ae863
--- /dev/null
+++ b/src/librustc_error_codes/error_codes/E0228.md
@@ -0,0 +1,40 @@
+The lifetime bound for this object type cannot be deduced from context and must
+be specified.
+
+Erroneous code example:
+
+```compile_fail,E0228
+trait Trait { }
+
+struct TwoBounds<'a, 'b, T: Sized + 'a + 'b> {
+    x: &'a i32,
+    y: &'b i32,
+    z: T,
+}
+
+type Foo<'a, 'b> = TwoBounds<'a, 'b, dyn Trait>;
+```
+
+When a trait object is used as a type argument of a generic type, Rust will try
+to infer its lifetime if unspecified. However, this isn't possible when the
+containing type has more than one lifetime bound.
+
+The above example can be resolved by either reducing the number of lifetime
+bounds to one or by making the trait object lifetime explicit, like so:
+
+```
+trait Trait { }
+
+struct TwoBounds<'a, 'b, T: Sized + 'a + 'b> {
+    x: &'a i32,
+    y: &'b i32,
+    z: T,
+}
+
+type Foo<'a, 'b> = TwoBounds<'a, 'b, dyn Trait + 'b>;
+```
+
+For more information, see [RFC 599] and its amendment [RFC 1156].
+
+[RFC 599]: https://github.com/rust-lang/rfcs/blob/master/text/0599-default-object-bound.md
+[RFC 1156]: https://github.com/rust-lang/rfcs/blob/master/text/1156-adjust-default-object-bounds.md
diff --git a/src/librustc_error_codes/error_codes/E0307.md b/src/librustc_error_codes/error_codes/E0307.md
index 52707b93acc..0d29d56ea1a 100644
--- a/src/librustc_error_codes/error_codes/E0307.md
+++ b/src/librustc_error_codes/error_codes/E0307.md
@@ -64,7 +64,7 @@ impl Trait for Foo {
 }
 ```
 
-The nightly feature [Arbintrary self types][AST] extends the accepted
+The nightly feature [Arbitrary self types][AST] extends the accepted
 set of receiver types to also include any type that can dereference to
 `Self`:
 
diff --git a/src/librustc_error_codes/error_codes/E0571.md b/src/librustc_error_codes/error_codes/E0571.md
index c2a3a8d7588..eadae05aa30 100644
--- a/src/librustc_error_codes/error_codes/E0571.md
+++ b/src/librustc_error_codes/error_codes/E0571.md
@@ -7,7 +7,7 @@ Example of erroneous code:
 # fn satisfied(n: usize) -> bool { n % 23 == 0 }
 let result = while true {
     if satisfied(i) {
-        break 2*i; // error: `break` with value from a `while` loop
+        break 2 * i; // error: `break` with value from a `while` loop
     }
     i += 1;
 };
@@ -22,9 +22,9 @@ Make sure `break value;` statements only occur in `loop` loops:
 ```
 # let mut i = 1;
 # fn satisfied(n: usize) -> bool { n % 23 == 0 }
-let result = loop { // ok!
+let result = loop { // This is now a "loop" loop.
     if satisfied(i) {
-        break 2*i;
+        break 2 * i; // ok!
     }
     i += 1;
 };
diff --git a/src/librustc_error_codes/error_codes/E0579.md b/src/librustc_error_codes/error_codes/E0579.md
index 225e27f0cab..f554242a3d4 100644
--- a/src/librustc_error_codes/error_codes/E0579.md
+++ b/src/librustc_error_codes/error_codes/E0579.md
@@ -1,7 +1,4 @@
-When matching against an exclusive range, the compiler verifies that the range
-is non-empty. Exclusive range patterns include the start point but not the end
-point, so this is equivalent to requiring the start of the range to be less
-than the end of the range.
+A lower range wasn't less than the upper range.
 
 Erroneous code example:
 
@@ -17,3 +14,8 @@ fn main() {
     }
 }
 ```
+
+When matching against an exclusive range, the compiler verifies that the range
+is non-empty. Exclusive range patterns include the start point but not the end
+point, so this is equivalent to requiring the start of the range to be less
+than the end of the range.
diff --git a/src/librustc_error_codes/error_codes/E0581.md b/src/librustc_error_codes/error_codes/E0581.md
index 947ec255a9d..89f6e3269ec 100644
--- a/src/librustc_error_codes/error_codes/E0581.md
+++ b/src/librustc_error_codes/error_codes/E0581.md
@@ -1,4 +1,4 @@
-In a `fn` type, a lifetime appears only in the return type,
+In a `fn` type, a lifetime appears only in the return type
 and not in the arguments types.
 
 Erroneous code example:
@@ -10,8 +10,11 @@ fn main() {
 }
 ```
 
-To fix this issue, either use the lifetime in the arguments, or use
-`'static`. Example:
+The problem here is that the lifetime isn't contrained by any of the arguments,
+making it impossible to determine how long it's supposed to live.
+
+To fix this issue, either use the lifetime in the arguments, or use the
+`'static` lifetime. Example:
 
 ```
 fn main() {
diff --git a/src/librustc_error_codes/error_codes/E0582.md b/src/librustc_error_codes/error_codes/E0582.md
index c0cf44852c4..e50cc60ea33 100644
--- a/src/librustc_error_codes/error_codes/E0582.md
+++ b/src/librustc_error_codes/error_codes/E0582.md
@@ -1,5 +1,5 @@
-A lifetime appears only in an associated-type binding,
-and not in the input types to the trait.
+A lifetime is only present in an associated-type binding, and not in the input
+types to the trait.
 
 Erroneous code example:
 
diff --git a/src/librustc_error_codes/error_codes/E0589.md b/src/librustc_error_codes/error_codes/E0589.md
index 5e15a875b0b..8a4f8d21725 100644
--- a/src/librustc_error_codes/error_codes/E0589.md
+++ b/src/librustc_error_codes/error_codes/E0589.md
@@ -1,6 +1,8 @@
 The value of `N` that was specified for `repr(align(N))` was not a power
 of two, or was greater than 2^29.
 
+Erroneous code example:
+
 ```compile_fail,E0589
 #[repr(align(15))] // error: invalid `repr(align)` attribute: not a power of two
 enum Foo {
diff --git a/src/librustc_error_codes/error_codes/E0754.md b/src/librustc_error_codes/error_codes/E0754.md
new file mode 100644
index 00000000000..abdc01ed21a
--- /dev/null
+++ b/src/librustc_error_codes/error_codes/E0754.md
@@ -0,0 +1,33 @@
+An non-ascii identifier was used in an invalid context.
+
+Erroneous code example:
+
+```compile_fail,E0754
+# #![feature(non_ascii_idents)]
+
+mod řųśť;
+// ^ error!
+fn main() {}
+```
+
+```compile_fail,E0754
+# #![feature(non_ascii_idents)]
+
+#[no_mangle]
+fn řųśť() {}
+// ^ error!
+fn main() {}
+```
+
+Non-ascii can be used as module names if it is inline
+or a #\[path\] attribute is specified. For example:
+
+```
+# #![feature(non_ascii_idents)]
+
+mod řųśť {
+    const IS_GREAT: bool = true;
+}
+
+fn main() {}
+```
diff --git a/src/librustc_error_codes/error_codes/E0755.md b/src/librustc_error_codes/error_codes/E0755.md
index b6eb2e34ccf..0c289146176 100644
--- a/src/librustc_error_codes/error_codes/E0755.md
+++ b/src/librustc_error_codes/error_codes/E0755.md
@@ -3,7 +3,7 @@ or `Self` that references lifetimes from a parent scope.
 
 Erroneous code example:
 
-```compile_fail,E0754,edition2018
+```compile_fail,E0755,edition2018
 struct S<'a>(&'a i32);
 
 impl<'a> S<'a> {