Auto merge of #87698 - camsteffen:rollup-yvjfc26, r=camsteffen

Rollup of 6 pull requests

Successful merges:

 - #86176 (Implement a `explicit_generic_args_with_impl_trait` feature gate)
 - #87654 (Add documentation for the order of Option and Result)
 - #87659 (Fix invalid suggestions for non-ASCII characters in byte constants)
 - #87673 (Tweak opaque type mismatch error)
 - #87687 (Inline some macros)
 - #87690 (Add missing "allocated object" doc link to `<*mut T>::add`)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

19 files changed, 189 insertions, 69 deletions

diff --git a/src/test/ui/async-await/dont-suggest-missing-await.stderr b/src/test/ui/async-await/dont-suggest-missing-await.stderr
index 654a3bcc92d..4dc5cafb986 100644
--- a/src/test/ui/async-await/dont-suggest-missing-await.stderr
+++ b/src/test/ui/async-await/dont-suggest-missing-await.stderr
@@ -1,13 +1,14 @@
 error[E0308]: mismatched types
   --> $DIR/dont-suggest-missing-await.rs:14:18
    |
-LL | async fn make_u32() -> u32 {
-   |                        --- checked the `Output` of this `async fn`, found opaque type
-...
 LL |         take_u32(x)
    |                  ^ expected `u32`, found opaque type
    |
-   = note: while checking the return type of the `async fn`
+note: while checking the return type of the `async fn`
+  --> $DIR/dont-suggest-missing-await.rs:7:24
+   |
+LL | async fn make_u32() -> u32 {
+   |                        ^^^ checked the `Output` of this `async fn`, found opaque type
    = note:     expected type `u32`
            found opaque type `impl Future`
 help: consider `await`ing on the `Future`
diff --git a/src/test/ui/async-await/generator-desc.stderr b/src/test/ui/async-await/generator-desc.stderr
index 04f191cc5e8..a7aedbb2b32 100644
--- a/src/test/ui/async-await/generator-desc.stderr
+++ b/src/test/ui/async-await/generator-desc.stderr
@@ -12,16 +12,19 @@ LL |     fun(async {}, async {});
 error[E0308]: mismatched types
   --> $DIR/generator-desc.rs:12:16
    |
-LL | async fn one() {}
-   |                - checked the `Output` of this `async fn`, expected opaque type
-LL | async fn two() {}
-   |                - checked the `Output` of this `async fn`, found opaque type
-...
 LL |     fun(one(), two());
    |                ^^^^^ expected opaque type, found a different opaque type
    |
-   = note: while checking the return type of the `async fn`
-   = note: while checking the return type of the `async fn`
+note: while checking the return type of the `async fn`
+  --> $DIR/generator-desc.rs:5:16
+   |
+LL | async fn one() {}
+   |                ^ checked the `Output` of this `async fn`, expected opaque type
+note: while checking the return type of the `async fn`
+  --> $DIR/generator-desc.rs:6:16
+   |
+LL | async fn two() {}
+   |                ^ checked the `Output` of this `async fn`, found opaque type
    = note: expected opaque type `impl Future` (opaque type at <$DIR/generator-desc.rs:5:16>)
               found opaque type `impl Future` (opaque type at <$DIR/generator-desc.rs:6:16>)
    = help: consider `await`ing on both `Future`s
diff --git a/src/test/ui/async-await/issue-61076.rs b/src/test/ui/async-await/issue-61076.rs
index 9fe3313ee6c..220f0774e2d 100644
--- a/src/test/ui/async-await/issue-61076.rs
+++ b/src/test/ui/async-await/issue-61076.rs
@@ -57,6 +57,8 @@ async fn struct_() -> Struct {
 
 async fn tuple() -> Tuple {
     //~^ NOTE checked the `Output` of this `async fn`, expected opaque type
+    //~| NOTE while checking the return type of the `async fn`
+    //~| NOTE in this expansion of desugaring of `async` block or function
     Tuple(1i32)
 }
 
@@ -92,7 +94,6 @@ async fn match_() {
         Tuple(_) => {} //~ ERROR mismatched types
         //~^ NOTE expected opaque type, found struct `Tuple`
         //~| NOTE expected opaque type `impl Future`
-        //~| NOTE while checking the return type of the `async fn`
     }
 }
 
diff --git a/src/test/ui/async-await/issue-61076.stderr b/src/test/ui/async-await/issue-61076.stderr
index ba97e135790..9fb2d5bc6cb 100644
--- a/src/test/ui/async-await/issue-61076.stderr
+++ b/src/test/ui/async-await/issue-61076.stderr
@@ -16,7 +16,7 @@ LL |     foo().await?;
    |          ^^^^^^
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/issue-61076.rs:65:5
+  --> $DIR/issue-61076.rs:67:5
    |
 LL |     t?;
    |     ^^ the `?` operator cannot be applied to type `T`
@@ -33,7 +33,7 @@ LL |     t.await?;
    |      ^^^^^^
 
 error[E0609]: no field `0` on type `impl Future`
-  --> $DIR/issue-61076.rs:76:26
+  --> $DIR/issue-61076.rs:78:26
    |
 LL |     let _: i32 = tuple().0;
    |                          ^ field not available in `impl Future`, but it is available in its `Output`
@@ -44,7 +44,7 @@ LL |     let _: i32 = tuple().await.0;
    |                         ^^^^^^
 
 error[E0609]: no field `a` on type `impl Future`
-  --> $DIR/issue-61076.rs:80:28
+  --> $DIR/issue-61076.rs:82:28
    |
 LL |     let _: i32 = struct_().a;
    |                            ^ field not available in `impl Future`, but it is available in its `Output`
@@ -55,7 +55,7 @@ LL |     let _: i32 = struct_().await.a;
    |                           ^^^^^^
 
 error[E0599]: no method named `method` found for opaque type `impl Future` in the current scope
-  --> $DIR/issue-61076.rs:84:15
+  --> $DIR/issue-61076.rs:86:15
    |
 LL |     struct_().method();
    |               ^^^^^^ method not found in `impl Future`
@@ -66,15 +66,16 @@ LL |     struct_().await.method();
    |               ^^^^^^
 
 error[E0308]: mismatched types
-  --> $DIR/issue-61076.rs:92:9
+  --> $DIR/issue-61076.rs:94:9
    |
-LL | async fn tuple() -> Tuple {
-   |                     ----- checked the `Output` of this `async fn`, expected opaque type
-...
 LL |         Tuple(_) => {}
    |         ^^^^^^^^ expected opaque type, found struct `Tuple`
    |
-   = note: while checking the return type of the `async fn`
+note: while checking the return type of the `async fn`
+  --> $DIR/issue-61076.rs:58:21
+   |
+LL | async fn tuple() -> Tuple {
+   |                     ^^^^^ checked the `Output` of this `async fn`, expected opaque type
    = note: expected opaque type `impl Future`
                    found struct `Tuple`
 help: consider `await`ing on the `Future`
diff --git a/src/test/ui/async-await/suggest-missing-await-closure.stderr b/src/test/ui/async-await/suggest-missing-await-closure.stderr
index 483e52536a1..9d742049046 100644
--- a/src/test/ui/async-await/suggest-missing-await-closure.stderr
+++ b/src/test/ui/async-await/suggest-missing-await-closure.stderr
@@ -1,13 +1,14 @@
 error[E0308]: mismatched types
   --> $DIR/suggest-missing-await-closure.rs:16:18
    |
-LL | async fn make_u32() -> u32 {
-   |                        --- checked the `Output` of this `async fn`, found opaque type
-...
 LL |         take_u32(x)
    |                  ^ expected `u32`, found opaque type
    |
-   = note: while checking the return type of the `async fn`
+note: while checking the return type of the `async fn`
+  --> $DIR/suggest-missing-await-closure.rs:8:24
+   |
+LL | async fn make_u32() -> u32 {
+   |                        ^^^ checked the `Output` of this `async fn`, found opaque type
    = note:     expected type `u32`
            found opaque type `impl Future`
 help: consider `await`ing on the `Future`
diff --git a/src/test/ui/async-await/suggest-missing-await.stderr b/src/test/ui/async-await/suggest-missing-await.stderr
index 14b5ee95ee8..890f66c58d0 100644
--- a/src/test/ui/async-await/suggest-missing-await.stderr
+++ b/src/test/ui/async-await/suggest-missing-await.stderr
@@ -1,13 +1,14 @@
 error[E0308]: mismatched types
   --> $DIR/suggest-missing-await.rs:12:14
    |
-LL | async fn make_u32() -> u32 {
-   |                        --- checked the `Output` of this `async fn`, found opaque type
-...
 LL |     take_u32(x)
    |              ^ expected `u32`, found opaque type
    |
-   = note: while checking the return type of the `async fn`
+note: while checking the return type of the `async fn`
+  --> $DIR/suggest-missing-await.rs:5:24
+   |
+LL | async fn make_u32() -> u32 {
+   |                        ^^^ checked the `Output` of this `async fn`, found opaque type
    = note:     expected type `u32`
            found opaque type `impl Future`
 help: consider `await`ing on the `Future`
@@ -18,13 +19,14 @@ LL |     take_u32(x.await)
 error[E0308]: mismatched types
   --> $DIR/suggest-missing-await.rs:22:5
    |
-LL | async fn dummy() {}
-   |                  - checked the `Output` of this `async fn`, found opaque type
-...
 LL |     dummy()
    |     ^^^^^^^ expected `()`, found opaque type
    |
-   = note: while checking the return type of the `async fn`
+note: while checking the return type of the `async fn`
+  --> $DIR/suggest-missing-await.rs:18:18
+   |
+LL | async fn dummy() {}
+   |                  ^ checked the `Output` of this `async fn`, found opaque type
    = note: expected unit type `()`
             found opaque type `impl Future`
 help: consider `await`ing on the `Future`
diff --git a/src/test/ui/attributes/key-value-non-ascii.stderr b/src/test/ui/attributes/key-value-non-ascii.stderr
index 1d4b0d5b2b1..01a07ad3b0e 100644
--- a/src/test/ui/attributes/key-value-non-ascii.stderr
+++ b/src/test/ui/attributes/key-value-non-ascii.stderr
@@ -2,10 +2,12 @@ error: non-ASCII character in byte constant
   --> $DIR/key-value-non-ascii.rs:3:19
    |
 LL | #[rustc_dummy = b"ffi.rs"]
-   |                   ^
-   |                   |
-   |                   byte constant must be ASCII
-   |                   help: use a \xHH escape for a non-ASCII byte: `\xFB03`
+   |                   ^ byte constant must be ASCII
+   |
+help: if you meant to use the UTF-8 encoding of 'ffi', use \xHH escapes
+   |
+LL | #[rustc_dummy = b"/xEF/xAC/x83.rs"]
+   |                   ^^^^^^^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/explicit-generic-args-for-impl.rs b/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/explicit-generic-args-for-impl.rs
new file mode 100644
index 00000000000..832a3e3b7b1
--- /dev/null
+++ b/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/explicit-generic-args-for-impl.rs
@@ -0,0 +1,7 @@
+#![feature(explicit_generic_args_with_impl_trait)]
+
+fn foo<T: ?Sized>(_f: impl AsRef<T>) {}
+
+fn main() {
+    foo::<str, String>("".to_string()); //~ ERROR E0107
+}
diff --git a/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/explicit-generic-args-for-impl.stderr b/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/explicit-generic-args-for-impl.stderr
new file mode 100644
index 00000000000..739e55e2943
--- /dev/null
+++ b/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/explicit-generic-args-for-impl.stderr
@@ -0,0 +1,17 @@
+error[E0107]: this function takes at most 1 generic argument but 2 generic arguments were supplied
+  --> $DIR/explicit-generic-args-for-impl.rs:6:5
+   |
+LL |     foo::<str, String>("".to_string());
+   |     ^^^        ------ help: remove this generic argument
+   |     |
+   |     expected at most 1 generic argument
+   |
+note: function defined here, with at most 1 generic parameter: `T`
+  --> $DIR/explicit-generic-args-for-impl.rs:3:4
+   |
+LL | fn foo<T: ?Sized>(_f: impl AsRef<T>) {}
+   |    ^^^ -
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0107`.
diff --git a/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/explicit-generic-args.rs b/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/explicit-generic-args.rs
new file mode 100644
index 00000000000..a6585bcf848
--- /dev/null
+++ b/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/explicit-generic-args.rs
@@ -0,0 +1,9 @@
+// check-pass
+
+#![feature(explicit_generic_args_with_impl_trait)]
+
+fn foo<T: ?Sized>(_f: impl AsRef<T>) {}
+
+fn main() {
+    foo::<str>("".to_string());
+}
diff --git a/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/feature-gate.rs b/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/feature-gate.rs
new file mode 100644
index 00000000000..0e4d6986d46
--- /dev/null
+++ b/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/feature-gate.rs
@@ -0,0 +1,7 @@
+// gate-test-explicit_generic_args_with_impl_trait
+
+fn foo<T: ?Sized>(_f: impl AsRef<T>) {}
+
+fn main() {
+    foo::<str>("".to_string()); //~ ERROR E0632
+}
diff --git a/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/feature-gate.stderr b/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/feature-gate.stderr
new file mode 100644
index 00000000000..6adc4e6b239
--- /dev/null
+++ b/src/test/ui/impl-trait/explicit-generic-args-with-impl-trait/feature-gate.stderr
@@ -0,0 +1,9 @@
+error[E0632]: cannot provide explicit generic arguments when `impl Trait` is used in argument position
+  --> $DIR/feature-gate.rs:6:11
+   |
+LL |     foo::<str>("".to_string());
+   |           ^^^ explicit generic argument not allowed
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0632`.
diff --git a/src/test/ui/parser/byte-literals.stderr b/src/test/ui/parser/byte-literals.stderr
index 55be113e16b..b9fb42088d9 100644
--- a/src/test/ui/parser/byte-literals.stderr
+++ b/src/test/ui/parser/byte-literals.stderr
@@ -36,10 +36,12 @@ error: non-ASCII character in byte constant
   --> $DIR/byte-literals.rs:10:7
    |
 LL |     b'é';
-   |       ^
-   |       |
-   |       byte constant must be ASCII
-   |       help: use a \xHH escape for a non-ASCII byte: `\xE9`
+   |       ^ byte constant must be ASCII
+   |
+help: if you meant to use the unicode code point for 'é', use a \xHH escape
+   |
+LL |     b'\xE9';
+   |       ^^^^
 
 error[E0763]: unterminated byte constant
   --> $DIR/byte-literals.rs:11:6
diff --git a/src/test/ui/parser/byte-string-literals.stderr b/src/test/ui/parser/byte-string-literals.stderr
index 3a5a8b331d3..4f22a16224f 100644
--- a/src/test/ui/parser/byte-string-literals.stderr
+++ b/src/test/ui/parser/byte-string-literals.stderr
@@ -24,10 +24,12 @@ error: non-ASCII character in byte constant
   --> $DIR/byte-string-literals.rs:6:7
    |
 LL |     b"é";
-   |       ^
-   |       |
-   |       byte constant must be ASCII
-   |       help: use a \xHH escape for a non-ASCII byte: `\xE9`
+   |       ^ byte constant must be ASCII
+   |
+help: if you meant to use the unicode code point for 'é', use a \xHH escape
+   |
+LL |     b"\xE9";
+   |       ^^^^
 
 error: raw byte string must be ASCII
   --> $DIR/byte-string-literals.rs:7:10
diff --git a/src/test/ui/suggestions/issue-81839.stderr b/src/test/ui/suggestions/issue-81839.stderr
index f9076587087..1e0aa9ce40d 100644
--- a/src/test/ui/suggestions/issue-81839.stderr
+++ b/src/test/ui/suggestions/issue-81839.stderr
@@ -13,13 +13,12 @@ LL | |         _ => cx.answer_str("hi"),
    | |              ^^^^^^^^^^^^^^^^^^^ expected `()`, found opaque type
 LL | |     }
    | |_____- `match` arms have incompatible types
-   | 
-  ::: $DIR/auxiliary/issue-81839.rs:6:49
    |
-LL |       pub async fn answer_str(&self, _s: &str) -> Test {
-   |                                                   ---- checked the `Output` of this `async fn`, found opaque type
+note: while checking the return type of the `async fn`
+  --> $DIR/auxiliary/issue-81839.rs:6:49
    |
-   = note: while checking the return type of the `async fn`
+LL |     pub async fn answer_str(&self, _s: &str) -> Test {
+   |                                                 ^^^^ checked the `Output` of this `async fn`, found opaque type
    = note:     expected type `()`
            found opaque type `impl Future`
 
diff --git a/src/test/ui/suggestions/match-prev-arm-needing-semi.rs b/src/test/ui/suggestions/match-prev-arm-needing-semi.rs
index 3b2cff3140d..990a4469764 100644
--- a/src/test/ui/suggestions/match-prev-arm-needing-semi.rs
+++ b/src/test/ui/suggestions/match-prev-arm-needing-semi.rs
@@ -14,8 +14,14 @@ fn extra_semicolon() {
 }
 
 async fn async_dummy() {} //~ NOTE checked the `Output` of this `async fn`, found opaque type
+//~| NOTE while checking the return type of the `async fn`
+//~| NOTE in this expansion of desugaring of `async` block or function
 async fn async_dummy2() {} //~ NOTE checked the `Output` of this `async fn`, found opaque type
 //~| NOTE checked the `Output` of this `async fn`, found opaque type
+//~| NOTE while checking the return type of the `async fn`
+//~| NOTE in this expansion of desugaring of `async` block or function
+//~| NOTE while checking the return type of the `async fn`
+//~| NOTE in this expansion of desugaring of `async` block or function
 
 async fn async_extra_semicolon_same() {
     let _ = match true { //~ NOTE `match` arms have incompatible types
@@ -26,7 +32,6 @@ async fn async_extra_semicolon_same() {
         false => async_dummy(), //~ ERROR `match` arms have incompatible types
         //~^ NOTE expected `()`, found opaque type
         //~| NOTE expected type `()`
-        //~| NOTE while checking the return type of the `async fn`
         //~| HELP consider `await`ing on the `Future`
     };
 }
@@ -40,7 +45,6 @@ async fn async_extra_semicolon_different() {
         false => async_dummy2(), //~ ERROR `match` arms have incompatible types
         //~^ NOTE expected `()`, found opaque type
         //~| NOTE expected type `()`
-        //~| NOTE while checking the return type of the `async fn`
         //~| HELP consider `await`ing on the `Future`
     };
 }
@@ -53,7 +57,6 @@ async fn async_different_futures() {
         //~^ NOTE expected opaque type, found a different opaque type
         //~| NOTE expected type `impl Future`
         //~| NOTE distinct uses of `impl Trait` result in different opaque types
-        //~| NOTE while checking the return type of the `async fn`
     };
 }
 
diff --git a/src/test/ui/suggestions/match-prev-arm-needing-semi.stderr b/src/test/ui/suggestions/match-prev-arm-needing-semi.stderr
index e31ea9679b5..9e64b539f0f 100644
--- a/src/test/ui/suggestions/match-prev-arm-needing-semi.stderr
+++ b/src/test/ui/suggestions/match-prev-arm-needing-semi.stderr
@@ -1,9 +1,6 @@
 error[E0308]: `match` arms have incompatible types
-  --> $DIR/match-prev-arm-needing-semi.rs:26:18
+  --> $DIR/match-prev-arm-needing-semi.rs:32:18
    |
-LL |   async fn async_dummy() {}
-   |                          - checked the `Output` of this `async fn`, found opaque type
-...
 LL |       let _ = match true {
    |  _____________-
 LL | |         true => {
@@ -18,7 +15,11 @@ LL | |
 LL | |     };
    | |_____- `match` arms have incompatible types
    |
-   = note: while checking the return type of the `async fn`
+note: while checking the return type of the `async fn`
+  --> $DIR/match-prev-arm-needing-semi.rs:16:24
+   |
+LL | async fn async_dummy() {}
+   |                        ^ checked the `Output` of this `async fn`, found opaque type
    = note:     expected type `()`
            found opaque type `impl Future`
 help: consider `await`ing on the `Future`
@@ -31,11 +32,8 @@ LL |             async_dummy()
    |                         --
 
 error[E0308]: `match` arms have incompatible types
-  --> $DIR/match-prev-arm-needing-semi.rs:40:18
+  --> $DIR/match-prev-arm-needing-semi.rs:45:18
    |
-LL |   async fn async_dummy2() {}
-   |                           - checked the `Output` of this `async fn`, found opaque type
-...
 LL |       let _ = match true {
    |  _____________-
 LL | |         true => {
@@ -50,7 +48,11 @@ LL | |
 LL | |     };
    | |_____- `match` arms have incompatible types
    |
-   = note: while checking the return type of the `async fn`
+note: while checking the return type of the `async fn`
+  --> $DIR/match-prev-arm-needing-semi.rs:19:25
+   |
+LL | async fn async_dummy2() {}
+   |                         ^ checked the `Output` of this `async fn`, found opaque type
    = note:     expected type `()`
            found opaque type `impl Future`
 help: consider `await`ing on the `Future`
@@ -66,11 +68,8 @@ LL |         false => Box::new(async_dummy2()),
    |
 
 error[E0308]: `match` arms have incompatible types
-  --> $DIR/match-prev-arm-needing-semi.rs:52:18
+  --> $DIR/match-prev-arm-needing-semi.rs:56:18
    |
-LL |   async fn async_dummy2() {}
-   |                           - checked the `Output` of this `async fn`, found opaque type
-...
 LL |       let _ = match true {
    |  _____________-
 LL | |         true => async_dummy(),
@@ -83,9 +82,13 @@ LL | |
 LL | |     };
    | |_____- `match` arms have incompatible types
    |
-   = note: while checking the return type of the `async fn`
+note: while checking the return type of the `async fn`
+  --> $DIR/match-prev-arm-needing-semi.rs:19:25
+   |
+LL | async fn async_dummy2() {}
+   |                         ^ checked the `Output` of this `async fn`, found opaque type
    = note:     expected type `impl Future` (opaque type at <$DIR/match-prev-arm-needing-semi.rs:16:24>)
-           found opaque type `impl Future` (opaque type at <$DIR/match-prev-arm-needing-semi.rs:17:25>)
+           found opaque type `impl Future` (opaque type at <$DIR/match-prev-arm-needing-semi.rs:19:25>)
    = note: distinct uses of `impl Trait` result in different opaque types
 help: consider `await`ing on both `Future`s
    |
diff --git a/src/test/ui/suggestions/multibyte-escapes.rs b/src/test/ui/suggestions/multibyte-escapes.rs
new file mode 100644
index 00000000000..fd5d46a4e92
--- /dev/null
+++ b/src/test/ui/suggestions/multibyte-escapes.rs
@@ -0,0 +1,18 @@
+// Regression test for #87397.
+
+fn main() {
+    b'µ';
+    //~^ ERROR: non-ASCII character in byte constant
+    //~| HELP: if you meant to use the unicode code point for 'µ', use a \xHH escape
+    //~| NOTE: byte constant must be ASCII
+
+    b'字';
+    //~^ ERROR: non-ASCII character in byte constant
+    //~| NOTE: this multibyte character does not fit into a single byte
+    //~| NOTE: byte constant must be ASCII
+
+    b"字";
+    //~^ ERROR: non-ASCII character in byte constant
+    //~| HELP: if you meant to use the UTF-8 encoding of '字', use \xHH escapes
+    //~| NOTE: byte constant must be ASCII
+}
diff --git a/src/test/ui/suggestions/multibyte-escapes.stderr b/src/test/ui/suggestions/multibyte-escapes.stderr
new file mode 100644
index 00000000000..bb4f8e8c304
--- /dev/null
+++ b/src/test/ui/suggestions/multibyte-escapes.stderr
@@ -0,0 +1,33 @@
+error: non-ASCII character in byte constant
+  --> $DIR/multibyte-escapes.rs:4:7
+   |
+LL |     b'µ';
+   |       ^ byte constant must be ASCII
+   |
+help: if you meant to use the unicode code point for 'µ', use a \xHH escape
+   |
+LL |     b'\xB5';
+   |       ^^^^
+
+error: non-ASCII character in byte constant
+  --> $DIR/multibyte-escapes.rs:9:7
+   |
+LL |     b'字';
+   |       ^^
+   |       |
+   |       byte constant must be ASCII
+   |       this multibyte character does not fit into a single byte
+
+error: non-ASCII character in byte constant
+  --> $DIR/multibyte-escapes.rs:14:7
+   |
+LL |     b"字";
+   |       ^^ byte constant must be ASCII
+   |
+help: if you meant to use the UTF-8 encoding of '字', use \xHH escapes
+   |
+LL |     b"\xE5\xAD\x97";
+   |       ^^^^^^^^^^^^
+
+error: aborting due to 3 previous errors
+