Auto merge of #78387 - Dylan-DPC:rollup-ch0st6z, r=Dylan-DPC

Rollup of 10 pull requests

Successful merges:

 - #74477 (`#[deny(unsafe_op_in_unsafe_fn)]` in sys/wasm)
 - #77836 (transmute_copy: explain that alignment is handled correctly)
 - #78126 (Properly define va_arg and va_list for aarch64-apple-darwin)
 - #78137 (Initialize tracing subscriber in compiletest tool)
 - #78161 (Add issue template link to IRLO)
 - #78214 (Tweak match arm semicolon removal suggestion to account for futures)
 - #78247 (Fix #78192)
 - #78252 (Add codegen test for #45964)
 - #78268 (Do not try to report on closures to avoid ICE)
 - #78295 (Add some regression tests)

Failed merges:

r? `@ghost`

22 files changed, 437 insertions, 131 deletions

diff --git a/src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.rs b/src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.rs
index 337487fc80b..554ac673d51 100644
--- a/src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.rs
+++ b/src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.rs
@@ -14,7 +14,6 @@ async fn foo2() -> Result<(), ()> {
 }
 async fn foo3() -> Result<(), ()> {
     let _ = await bar()?; //~ ERROR incorrect use of `await`
-    //~^ ERROR the `?` operator can only be applied to values that implement `Try`
     Ok(())
 }
 async fn foo21() -> Result<(), ()> {
@@ -60,9 +59,7 @@ fn foo10() -> Result<(), ()> {
     Ok(())
 }
 fn foo11() -> Result<(), ()> {
-    let _ = await bar()?; //~ ERROR `await` is only allowed inside `async` functions and blocks
-    //~^ ERROR incorrect use of `await`
-    //~| ERROR the `?` operator can only be applied to values that implement `Try`
+    let _ = await bar()?; //~ ERROR incorrect use of `await`
     Ok(())
 }
 fn foo12() -> Result<(), ()> {
diff --git a/src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.stderr b/src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.stderr
index 6a653fc060b..52615df6008 100644
--- a/src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.stderr
+++ b/src/test/ui/async-await/await-keyword/incorrect-syntax-suggestions.stderr
@@ -17,103 +17,103 @@ LL |     let _ = await bar()?;
    |             ^^^^^^^^^^^^ help: `await` is a postfix operation: `bar()?.await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:21:13
+  --> $DIR/incorrect-syntax-suggestions.rs:20:13
    |
 LL |     let _ = await { bar() };
    |             ^^^^^^^^^^^^^^^ help: `await` is a postfix operation: `{ bar() }.await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:25:13
+  --> $DIR/incorrect-syntax-suggestions.rs:24:13
    |
 LL |     let _ = await(bar());
    |             ^^^^^^^^^^^^ help: `await` is a postfix operation: `(bar()).await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:29:13
+  --> $DIR/incorrect-syntax-suggestions.rs:28:13
    |
 LL |     let _ = await { bar() }?;
    |             ^^^^^^^^^^^^^^^ help: `await` is a postfix operation: `{ bar() }.await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:33:14
+  --> $DIR/incorrect-syntax-suggestions.rs:32:14
    |
 LL |     let _ = (await bar())?;
    |              ^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:37:24
+  --> $DIR/incorrect-syntax-suggestions.rs:36:24
    |
 LL |     let _ = bar().await();
    |                        ^^ help: `await` is not a method call, remove the parentheses
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:41:24
+  --> $DIR/incorrect-syntax-suggestions.rs:40:24
    |
 LL |     let _ = bar().await()?;
    |                        ^^ help: `await` is not a method call, remove the parentheses
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:53:13
+  --> $DIR/incorrect-syntax-suggestions.rs:52:13
    |
 LL |     let _ = await bar();
    |             ^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:58:13
+  --> $DIR/incorrect-syntax-suggestions.rs:57:13
    |
 LL |     let _ = await? bar();
    |             ^^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await?`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:63:13
+  --> $DIR/incorrect-syntax-suggestions.rs:62:13
    |
 LL |     let _ = await bar()?;
    |             ^^^^^^^^^^^^ help: `await` is a postfix operation: `bar()?.await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:69:14
+  --> $DIR/incorrect-syntax-suggestions.rs:66:14
    |
 LL |     let _ = (await bar())?;
    |              ^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:74:24
+  --> $DIR/incorrect-syntax-suggestions.rs:71:24
    |
 LL |     let _ = bar().await();
    |                        ^^ help: `await` is not a method call, remove the parentheses
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:79:24
+  --> $DIR/incorrect-syntax-suggestions.rs:76:24
    |
 LL |     let _ = bar().await()?;
    |                        ^^ help: `await` is not a method call, remove the parentheses
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:107:13
+  --> $DIR/incorrect-syntax-suggestions.rs:104:13
    |
 LL |     let _ = await!(bar());
    |             ^^^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:111:13
+  --> $DIR/incorrect-syntax-suggestions.rs:108:13
    |
 LL |     let _ = await!(bar())?;
    |             ^^^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:116:17
+  --> $DIR/incorrect-syntax-suggestions.rs:113:17
    |
 LL |         let _ = await!(bar())?;
    |                 ^^^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:124:17
+  --> $DIR/incorrect-syntax-suggestions.rs:121:17
    |
 LL |         let _ = await!(bar())?;
    |                 ^^^^^^^^^^^^^ help: `await` is a postfix operation: `bar().await`
 
 error: expected expression, found `=>`
-  --> $DIR/incorrect-syntax-suggestions.rs:132:25
+  --> $DIR/incorrect-syntax-suggestions.rs:129:25
    |
 LL |     match await { await => () }
    |                   ----- ^^ expected expression
@@ -121,13 +121,13 @@ LL |     match await { await => () }
    |                   while parsing this incorrect await expression
 
 error: incorrect use of `await`
-  --> $DIR/incorrect-syntax-suggestions.rs:132:11
+  --> $DIR/incorrect-syntax-suggestions.rs:129:11
    |
 LL |     match await { await => () }
    |           ^^^^^^^^^^^^^^^^^^^^^ help: `await` is a postfix operation: `{ await => () }.await`
 
 error: expected one of `.`, `?`, `{`, or an operator, found `}`
-  --> $DIR/incorrect-syntax-suggestions.rs:135:1
+  --> $DIR/incorrect-syntax-suggestions.rs:132:1
    |
 LL |     match await { await => () }
    |     -----                      - expected one of `.`, `?`, `{`, or an operator
@@ -138,7 +138,7 @@ LL | }
    | ^ unexpected token
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:53:13
+  --> $DIR/incorrect-syntax-suggestions.rs:52:13
    |
 LL | fn foo9() -> Result<(), ()> {
    |    ---- this is not `async`
@@ -146,7 +146,7 @@ LL |     let _ = await bar();
    |             ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:58:13
+  --> $DIR/incorrect-syntax-suggestions.rs:57:13
    |
 LL | fn foo10() -> Result<(), ()> {
    |    ----- this is not `async`
@@ -154,15 +154,7 @@ LL |     let _ = await? bar();
    |             ^^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:63:13
-   |
-LL | fn foo11() -> Result<(), ()> {
-   |    ----- this is not `async`
-LL |     let _ = await bar()?;
-   |             ^^^^^^^^^^^^ only allowed inside `async` functions and blocks
-
-error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:69:14
+  --> $DIR/incorrect-syntax-suggestions.rs:66:14
    |
 LL | fn foo12() -> Result<(), ()> {
    |    ----- this is not `async`
@@ -170,7 +162,7 @@ LL |     let _ = (await bar())?;
    |              ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:74:13
+  --> $DIR/incorrect-syntax-suggestions.rs:71:13
    |
 LL | fn foo13() -> Result<(), ()> {
    |    ----- this is not `async`
@@ -178,7 +170,7 @@ LL |     let _ = bar().await();
    |             ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:79:13
+  --> $DIR/incorrect-syntax-suggestions.rs:76:13
    |
 LL | fn foo14() -> Result<(), ()> {
    |    ----- this is not `async`
@@ -186,7 +178,7 @@ LL |     let _ = bar().await()?;
    |             ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:84:13
+  --> $DIR/incorrect-syntax-suggestions.rs:81:13
    |
 LL | fn foo15() -> Result<(), ()> {
    |    ----- this is not `async`
@@ -194,7 +186,7 @@ LL |     let _ = bar().await;
    |             ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:88:13
+  --> $DIR/incorrect-syntax-suggestions.rs:85:13
    |
 LL | fn foo16() -> Result<(), ()> {
    |    ----- this is not `async`
@@ -202,7 +194,7 @@ LL |     let _ = bar().await?;
    |             ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:93:17
+  --> $DIR/incorrect-syntax-suggestions.rs:90:17
    |
 LL |     fn foo() -> Result<(), ()> {
    |        --- this is not `async`
@@ -210,7 +202,7 @@ LL |         let _ = bar().await?;
    |                 ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:100:17
+  --> $DIR/incorrect-syntax-suggestions.rs:97:17
    |
 LL |     let foo = || {
    |               -- this is not `async`
@@ -218,7 +210,7 @@ LL |         let _ = bar().await?;
    |                 ^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:116:17
+  --> $DIR/incorrect-syntax-suggestions.rs:113:17
    |
 LL |     fn foo() -> Result<(), ()> {
    |        --- this is not `async`
@@ -226,35 +218,13 @@ LL |         let _ = await!(bar())?;
    |                 ^^^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
 error[E0728]: `await` is only allowed inside `async` functions and blocks
-  --> $DIR/incorrect-syntax-suggestions.rs:124:17
+  --> $DIR/incorrect-syntax-suggestions.rs:121:17
    |
 LL |     let foo = || {
    |               -- this is not `async`
 LL |         let _ = await!(bar())?;
    |                 ^^^^^^^^^^^^^ only allowed inside `async` functions and blocks
 
-error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/incorrect-syntax-suggestions.rs:16:19
-   |
-LL |     let _ = await bar()?;
-   |                   ^^^^^^
-   |                   |
-   |                   the `?` operator cannot be applied to type `impl Future`
-   |                   help: consider using `.await` here: `bar().await?`
-   |
-   = help: the trait `Try` is not implemented for `impl Future`
-   = note: required by `into_result`
-
-error[E0277]: the `?` operator can only be applied to values that implement `Try`
-  --> $DIR/incorrect-syntax-suggestions.rs:63:19
-   |
-LL |     let _ = await bar()?;
-   |                   ^^^^^^ the `?` operator cannot be applied to type `impl Future`
-   |
-   = help: the trait `Try` is not implemented for `impl Future`
-   = note: required by `into_result`
-
-error: aborting due to 36 previous errors
+error: aborting due to 33 previous errors
 
-Some errors have detailed explanations: E0277, E0728.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0728`.
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 e70ed9badbd..14e72c2b1e7 100644
--- a/src/test/ui/async-await/dont-suggest-missing-await.stderr
+++ b/src/test/ui/async-await/dont-suggest-missing-await.stderr
@@ -9,6 +9,10 @@ LL |         take_u32(x)
    |
    = note:     expected type `u32`
            found opaque type `impl Future`
+help: consider `await`ing on the `Future`
+   |
+LL |         take_u32(x.await)
+   |                   ^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/async-await/issue-61076.stderr b/src/test/ui/async-await/issue-61076.stderr
index 88ea7251eaf..df54ac88ace 100644
--- a/src/test/ui/async-await/issue-61076.stderr
+++ b/src/test/ui/async-await/issue-61076.stderr
@@ -2,25 +2,27 @@ error[E0277]: the `?` operator can only be applied to values that implement `Try
   --> $DIR/issue-61076.rs:42:5
    |
 LL |     foo()?;
-   |     ^^^^^^
-   |     |
-   |     the `?` operator cannot be applied to type `impl Future`
-   |     help: consider using `.await` here: `foo().await?`
+   |     ^^^^^^ the `?` operator cannot be applied to type `impl Future`
    |
    = help: the trait `Try` is not implemented for `impl Future`
    = note: required by `into_result`
+help: consider `await`ing on the `Future`
+   |
+LL |     foo().await?;
+   |          ^^^^^^
 
 error[E0277]: the `?` operator can only be applied to values that implement `Try`
   --> $DIR/issue-61076.rs:56:5
    |
 LL |     t?;
-   |     ^^
-   |     |
-   |     the `?` operator cannot be applied to type `T`
-   |     help: consider using `.await` here: `t.await?`
+   |     ^^ the `?` operator cannot be applied to type `T`
    |
    = help: the trait `Try` is not implemented for `T`
    = note: required by `into_result`
+help: consider `await`ing on the `Future`
+   |
+LL |     t.await?;
+   |      ^^^^^^
 
 error[E0609]: no field `0` on type `impl Future`
   --> $DIR/issue-61076.rs:58:26
@@ -51,6 +53,10 @@ LL |         Tuple(_) => {}
    |
    = note: expected opaque type `impl Future`
                    found struct `Tuple`
+help: consider `await`ing on the `Future`
+   |
+LL |     match tuple().await {
+   |                  ^^^^^^
 
 error: aborting due to 6 previous errors
 
diff --git a/src/test/ui/async-await/suggest-missing-await-closure.fixed b/src/test/ui/async-await/suggest-missing-await-closure.fixed
index 37b30ffe680..febcd021842 100644
--- a/src/test/ui/async-await/suggest-missing-await-closure.fixed
+++ b/src/test/ui/async-await/suggest-missing-await-closure.fixed
@@ -15,8 +15,8 @@ async fn suggest_await_in_async_closure() {
         let x = make_u32();
         take_u32(x.await)
         //~^ ERROR mismatched types [E0308]
-        //~| HELP consider using `.await` here
-        //~| SUGGESTION x.await
+        //~| HELP consider `await`ing on the `Future`
+        //~| SUGGESTION .await
     };
 }
 
diff --git a/src/test/ui/async-await/suggest-missing-await-closure.rs b/src/test/ui/async-await/suggest-missing-await-closure.rs
index 18076a15161..faabf6ee3f1 100644
--- a/src/test/ui/async-await/suggest-missing-await-closure.rs
+++ b/src/test/ui/async-await/suggest-missing-await-closure.rs
@@ -15,8 +15,8 @@ async fn suggest_await_in_async_closure() {
         let x = make_u32();
         take_u32(x)
         //~^ ERROR mismatched types [E0308]
-        //~| HELP consider using `.await` here
-        //~| SUGGESTION x.await
+        //~| HELP consider `await`ing on the `Future`
+        //~| SUGGESTION .await
     };
 }
 
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 ed2c4cbfccc..2151057aa7f 100644
--- a/src/test/ui/async-await/suggest-missing-await-closure.stderr
+++ b/src/test/ui/async-await/suggest-missing-await-closure.stderr
@@ -5,13 +5,14 @@ LL | async fn make_u32() -> u32 {
    |                        --- the `Output` of this `async fn`'s found opaque type
 ...
 LL |         take_u32(x)
-   |                  ^
-   |                  |
-   |                  expected `u32`, found opaque type
-   |                  help: consider using `.await` here: `x.await`
+   |                  ^ expected `u32`, found opaque type
    |
    = note:     expected type `u32`
            found opaque type `impl Future`
+help: consider `await`ing on the `Future`
+   |
+LL |         take_u32(x.await)
+   |                   ^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/async-await/suggest-missing-await.fixed b/src/test/ui/async-await/suggest-missing-await.fixed
deleted file mode 100644
index 1ec59d90620..00000000000
--- a/src/test/ui/async-await/suggest-missing-await.fixed
+++ /dev/null
@@ -1,30 +0,0 @@
-// edition:2018
-// run-rustfix
-
-fn take_u32(_x: u32) {}
-
-async fn make_u32() -> u32 {
-    22
-}
-
-#[allow(unused)]
-async fn suggest_await_in_async_fn() {
-    let x = make_u32();
-    take_u32(x.await)
-    //~^ ERROR mismatched types [E0308]
-    //~| HELP consider using `.await` here
-    //~| SUGGESTION x.await
-}
-
-async fn dummy() {}
-
-#[allow(unused)]
-async fn suggest_await_in_async_fn_return() {
-    dummy().await;
-    //~^ ERROR mismatched types [E0308]
-    //~| HELP try adding a semicolon
-    //~| HELP consider using `.await` here
-    //~| SUGGESTION dummy().await
-}
-
-fn main() {}
diff --git a/src/test/ui/async-await/suggest-missing-await.rs b/src/test/ui/async-await/suggest-missing-await.rs
index 70cc1f1d5a2..d629054911d 100644
--- a/src/test/ui/async-await/suggest-missing-await.rs
+++ b/src/test/ui/async-await/suggest-missing-await.rs
@@ -1,5 +1,4 @@
 // edition:2018
-// run-rustfix
 
 fn take_u32(_x: u32) {}
 
@@ -12,8 +11,8 @@ async fn suggest_await_in_async_fn() {
     let x = make_u32();
     take_u32(x)
     //~^ ERROR mismatched types [E0308]
-    //~| HELP consider using `.await` here
-    //~| SUGGESTION x.await
+    //~| HELP consider `await`ing on the `Future`
+    //~| SUGGESTION .await
 }
 
 async fn dummy() {}
@@ -23,8 +22,8 @@ async fn suggest_await_in_async_fn_return() {
     dummy()
     //~^ ERROR mismatched types [E0308]
     //~| HELP try adding a semicolon
-    //~| HELP consider using `.await` here
-    //~| SUGGESTION dummy().await
+    //~| HELP consider `await`ing on the `Future`
+    //~| SUGGESTION .await
 }
 
 fn main() {}
diff --git a/src/test/ui/async-await/suggest-missing-await.stderr b/src/test/ui/async-await/suggest-missing-await.stderr
index c6355680e25..46615dae7e2 100644
--- a/src/test/ui/async-await/suggest-missing-await.stderr
+++ b/src/test/ui/async-await/suggest-missing-await.stderr
@@ -1,20 +1,21 @@
 error[E0308]: mismatched types
-  --> $DIR/suggest-missing-await.rs:13:14
+  --> $DIR/suggest-missing-await.rs:12:14
    |
 LL | async fn make_u32() -> u32 {
    |                        --- the `Output` of this `async fn`'s found opaque type
 ...
 LL |     take_u32(x)
-   |              ^
-   |              |
-   |              expected `u32`, found opaque type
-   |              help: consider using `.await` here: `x.await`
+   |              ^ expected `u32`, found opaque type
    |
    = note:     expected type `u32`
            found opaque type `impl Future`
+help: consider `await`ing on the `Future`
+   |
+LL |     take_u32(x.await)
+   |               ^^^^^^
 
 error[E0308]: mismatched types
-  --> $DIR/suggest-missing-await.rs:23:5
+  --> $DIR/suggest-missing-await.rs:22:5
    |
 LL | async fn dummy() {}
    |                  - the `Output` of this `async fn`'s found opaque type
@@ -24,14 +25,14 @@ LL |     dummy()
    |
    = note: expected unit type `()`
             found opaque type `impl Future`
+help: consider `await`ing on the `Future`
+   |
+LL |     dummy().await
+   |            ^^^^^^
 help: try adding a semicolon
    |
 LL |     dummy();
    |            ^
-help: consider using `.await` here
-   |
-LL |     dummy().await
-   |
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/issues/issue-56229.rs b/src/test/ui/issues/issue-56229.rs
new file mode 100644
index 00000000000..9e5897b9892
--- /dev/null
+++ b/src/test/ui/issues/issue-56229.rs
@@ -0,0 +1,35 @@
+// check-pass
+
+trait Mirror {
+    type Other;
+}
+
+#[derive(Debug)]
+struct Even(usize);
+struct Odd;
+
+impl Mirror for Even {
+    type Other = Odd;
+}
+
+impl Mirror for Odd {
+    type Other = Even;
+}
+
+trait Dyn<T: Mirror>: AsRef<<T as Mirror>::Other> {}
+
+impl Dyn<Odd> for Even {}
+
+impl AsRef<Even> for Even {
+    fn as_ref(&self) -> &Even {
+        self
+    }
+}
+
+fn code<T: Mirror>(d: &dyn Dyn<T>) -> &T::Other {
+    d.as_ref()
+}
+
+fn main() {
+    println!("{:?}", code(&Even(22)));
+}
diff --git a/src/test/ui/issues/issue-59494.rs b/src/test/ui/issues/issue-59494.rs
new file mode 100644
index 00000000000..06b8eb777c0
--- /dev/null
+++ b/src/test/ui/issues/issue-59494.rs
@@ -0,0 +1,23 @@
+fn t7p<A, B, C>(f: impl Fn(B) -> C, g: impl Fn(A) -> B) -> impl Fn(A) -> C {
+    move |a: A| -> C { f(g(a)) }
+}
+
+fn t8n<A, B, C>(f: impl Fn(A) -> B, g: impl Fn(A) -> C) -> impl Fn(A) -> (B, C)
+where
+    A: Copy,
+{
+    move |a: A| -> (B, C) {
+        let b = a;
+        let fa = f(a);
+        let ga = g(b);
+        (fa, ga)
+    }
+}
+
+fn main() {
+    let f = |(_, _)| {};
+    let g = |(a, _)| a;
+    let t7 = |env| |a| |b| t7p(f, g)(((env, a), b));
+    let t8 = t8n(t7, t7p(f, g));
+    //~^ ERROR: expected a `Fn<(_,)>` closure, found `impl Fn<(((_, _), _),)>
+}
diff --git a/src/test/ui/issues/issue-59494.stderr b/src/test/ui/issues/issue-59494.stderr
new file mode 100644
index 00000000000..e2ac5d94da1
--- /dev/null
+++ b/src/test/ui/issues/issue-59494.stderr
@@ -0,0 +1,14 @@
+error[E0277]: expected a `Fn<(_,)>` closure, found `impl Fn<(((_, _), _),)>`
+  --> $DIR/issue-59494.rs:21:22
+   |
+LL | fn t8n<A, B, C>(f: impl Fn(A) -> B, g: impl Fn(A) -> C) -> impl Fn(A) -> (B, C)
+   |                                             ---------- required by this bound in `t8n`
+...
+LL |     let t8 = t8n(t7, t7p(f, g));
+   |                      ^^^^^^^^^ expected an `Fn<(_,)>` closure, found `impl Fn<(((_, _), _),)>`
+   |
+   = help: the trait `Fn<(_,)>` is not implemented for `impl Fn<(((_, _), _),)>`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/issues/issue-70746.rs b/src/test/ui/issues/issue-70746.rs
new file mode 100644
index 00000000000..8930c15f57e
--- /dev/null
+++ b/src/test/ui/issues/issue-70746.rs
@@ -0,0 +1,29 @@
+// check-pass
+
+pub trait Trait1 {
+    type C;
+}
+
+struct T1;
+impl Trait1 for T1 {
+    type C = usize;
+}
+pub trait Callback<T: Trait1>: FnMut(<T as Trait1>::C) {}
+impl<T: Trait1, F: FnMut(<T as Trait1>::C)> Callback<T> for F {}
+
+pub struct State<T: Trait1> {
+    callback: Option<Box<dyn Callback<T>>>,
+}
+impl<T: Trait1> State<T> {
+    fn new() -> Self {
+        Self { callback: None }
+    }
+    fn test_cb(&mut self, d: <T as Trait1>::C) {
+        (self.callback.as_mut().unwrap())(d)
+    }
+}
+
+fn main() {
+    let mut s = State::<T1>::new();
+    s.test_cb(1);
+}
diff --git a/src/test/ui/issues/issue-73229.rs b/src/test/ui/issues/issue-73229.rs
new file mode 100644
index 00000000000..35346199add
--- /dev/null
+++ b/src/test/ui/issues/issue-73229.rs
@@ -0,0 +1,33 @@
+// check-pass
+
+fn any<T>() -> T {
+    loop {}
+}
+
+trait Foo {
+    type V;
+}
+
+trait Callback<T: Foo>: Fn(&T, &T::V) {}
+impl<T: Foo, F: Fn(&T, &T::V)> Callback<T> for F {}
+
+struct Bar<T: Foo> {
+    callback: Box<dyn Callback<T>>,
+}
+
+impl<T: Foo> Bar<T> {
+    fn event(&self) {
+        (self.callback)(any(), any());
+    }
+}
+
+struct A;
+struct B;
+impl Foo for A {
+    type V = B;
+}
+
+fn main() {
+    let foo = Bar::<A> { callback: Box::new(|_: &A, _: &B| ()) };
+    foo.event();
+}
diff --git a/src/test/ui/regions/issue-78262.default.stderr b/src/test/ui/regions/issue-78262.default.stderr
new file mode 100644
index 00000000000..e97b8eca948
--- /dev/null
+++ b/src/test/ui/regions/issue-78262.default.stderr
@@ -0,0 +1,18 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-78262.rs:12:28
+   |
+LL |     let f = |x: &dyn TT| x.func();
+   |                            ^^^^ lifetime mismatch
+   |
+   = note: expected reference `&(dyn TT + 'static)`
+              found reference `&dyn TT`
+note: the anonymous lifetime #1 defined on the body at 12:13...
+  --> $DIR/issue-78262.rs:12:13
+   |
+LL |     let f = |x: &dyn TT| x.func();
+   |             ^^^^^^^^^^^^^^^^^^^^^
+   = note: ...does not necessarily outlive the static lifetime
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/regions/issue-78262.nll.stderr b/src/test/ui/regions/issue-78262.nll.stderr
new file mode 100644
index 00000000000..4607dbad422
--- /dev/null
+++ b/src/test/ui/regions/issue-78262.nll.stderr
@@ -0,0 +1,10 @@
+error[E0521]: borrowed data escapes outside of closure
+  --> $DIR/issue-78262.rs:12:26
+   |
+LL |     let f = |x: &dyn TT| x.func();
+   |              -           ^^^^^^^^ `x` escapes the closure body here
+   |              |
+   |              `x` is a reference that is only valid in the closure body
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/regions/issue-78262.rs b/src/test/ui/regions/issue-78262.rs
new file mode 100644
index 00000000000..0bdb0abac30
--- /dev/null
+++ b/src/test/ui/regions/issue-78262.rs
@@ -0,0 +1,14 @@
+// revisions: nll default
+// ignore-compare-mode-nll
+//[nll]compile-flags: -Z borrowck=mir
+
+trait TT {}
+
+impl dyn TT {
+    fn func(&self) {}
+}
+
+fn main() {
+    let f = |x: &dyn TT| x.func(); //[default]~ ERROR: mismatched types
+    //[nll]~^ ERROR: borrowed data escapes outside of closure
+}
diff --git a/src/test/ui/suggestions/issue-72766.stderr b/src/test/ui/suggestions/issue-72766.stderr
index a1a5949b196..5c9c549fa07 100644
--- a/src/test/ui/suggestions/issue-72766.stderr
+++ b/src/test/ui/suggestions/issue-72766.stderr
@@ -2,13 +2,14 @@ error[E0277]: the `?` operator can only be applied to values that implement `Try
   --> $DIR/issue-72766.rs:14:5
    |
 LL |     SadGirl {}.call()?;
-   |     ^^^^^^^^^^^^^^^^^^
-   |     |
-   |     the `?` operator cannot be applied to type `impl Future`
-   |     help: consider using `.await` here: `SadGirl {}.call().await?`
+   |     ^^^^^^^^^^^^^^^^^^ the `?` operator cannot be applied to type `impl Future`
    |
    = help: the trait `Try` is not implemented for `impl Future`
    = note: required by `into_result`
+help: consider `await`ing on the `Future`
+   |
+LL |     SadGirl {}.call().await?;
+   |                      ^^^^^^
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/suggestions/match-prev-arm-needing-semi.rs b/src/test/ui/suggestions/match-prev-arm-needing-semi.rs
new file mode 100644
index 00000000000..b8ac030b0bb
--- /dev/null
+++ b/src/test/ui/suggestions/match-prev-arm-needing-semi.rs
@@ -0,0 +1,57 @@
+// edition:2018
+
+fn dummy() -> i32 { 42 }
+
+fn extra_semicolon() {
+    let _ = match true { //~ NOTE `match` arms have incompatible types
+        true => {
+            dummy(); //~ NOTE this is found to be
+            //~^ HELP consider removing this semicolon
+        }
+        false => dummy(), //~ ERROR `match` arms have incompatible types
+        //~^ NOTE expected `()`, found `i32`
+    };
+}
+
+async fn async_dummy() {} //~ NOTE the `Output` of this `async fn`'s found opaque type
+async fn async_dummy2() {} //~ NOTE the `Output` of this `async fn`'s found opaque type
+//~^ NOTE the `Output` of this `async fn`'s found opaque type
+
+async fn async_extra_semicolon_same() {
+    let _ = match true { //~ NOTE `match` arms have incompatible types
+        true => {
+            async_dummy(); //~ NOTE this is found to be
+            //~^ HELP consider removing this semicolon
+        }
+        false => async_dummy(), //~ ERROR `match` arms have incompatible types
+        //~^ NOTE expected `()`, found opaque type
+        //~| NOTE expected type `()`
+        //~| HELP consider `await`ing on the `Future`
+    };
+}
+
+async fn async_extra_semicolon_different() {
+    let _ = match true { //~ NOTE `match` arms have incompatible types
+        true => {
+            async_dummy(); //~ NOTE this is found to be
+            //~^ HELP consider removing this semicolon
+        }
+        false => async_dummy2(), //~ ERROR `match` arms have incompatible types
+        //~^ NOTE expected `()`, found opaque type
+        //~| NOTE expected type `()`
+        //~| HELP consider `await`ing on the `Future`
+    };
+}
+
+async fn async_different_futures() {
+    let _ = match true { //~ NOTE `match` arms have incompatible types
+        true => async_dummy(), //~ NOTE this is found to be
+        //~| HELP consider `await`ing on both `Future`s
+        false => async_dummy2(), //~ ERROR `match` arms have incompatible types
+        //~^ 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
+    };
+}
+
+fn main() {}
diff --git a/src/test/ui/suggestions/match-prev-arm-needing-semi.stderr b/src/test/ui/suggestions/match-prev-arm-needing-semi.stderr
new file mode 100644
index 00000000000..e9803a78f94
--- /dev/null
+++ b/src/test/ui/suggestions/match-prev-arm-needing-semi.stderr
@@ -0,0 +1,118 @@
+error[E0308]: `match` arms have incompatible types
+  --> $DIR/match-prev-arm-needing-semi.rs:26:18
+   |
+LL |   async fn async_dummy() {}
+   |                          - the `Output` of this `async fn`'s found opaque type
+...
+LL |       let _ = match true {
+   |  _____________-
+LL | |         true => {
+LL | |             async_dummy();
+   | |             -------------- this is found to be of type `()`
+LL | |
+LL | |         }
+LL | |         false => async_dummy(),
+   | |                  ^^^^^^^^^^^^^ expected `()`, found opaque type
+...  |
+LL | |
+LL | |     };
+   | |_____- `match` arms have incompatible types
+   |
+   = note:     expected type `()`
+           found opaque type `impl Future`
+help: consider `await`ing on the `Future`
+   |
+LL |         false => async_dummy().await,
+   |                               ^^^^^^
+help: consider removing this semicolon and boxing the expressions
+   |
+LL |             Box::new(async_dummy())
+LL |
+LL |         }
+LL |         false => Box::new(async_dummy()),
+   |
+
+error[E0308]: `match` arms have incompatible types
+  --> $DIR/match-prev-arm-needing-semi.rs:39:18
+   |
+LL |   async fn async_dummy2() {}
+   |                           - the `Output` of this `async fn`'s found opaque type
+...
+LL |       let _ = match true {
+   |  _____________-
+LL | |         true => {
+LL | |             async_dummy();
+   | |             -------------- this is found to be of type `()`
+LL | |
+LL | |         }
+LL | |         false => async_dummy2(),
+   | |                  ^^^^^^^^^^^^^^ expected `()`, found opaque type
+...  |
+LL | |
+LL | |     };
+   | |_____- `match` arms have incompatible types
+   |
+   = note:     expected type `()`
+           found opaque type `impl Future`
+help: consider `await`ing on the `Future`
+   |
+LL |         false => async_dummy2().await,
+   |                                ^^^^^^
+help: consider removing this semicolon and boxing the expressions
+   |
+LL |             Box::new(async_dummy())
+LL |
+LL |         }
+LL |         false => Box::new(async_dummy2()),
+   |
+
+error[E0308]: `match` arms have incompatible types
+  --> $DIR/match-prev-arm-needing-semi.rs:50:18
+   |
+LL |   async fn async_dummy2() {}
+   |                           - the `Output` of this `async fn`'s found opaque type
+...
+LL |       let _ = match true {
+   |  _____________-
+LL | |         true => async_dummy(),
+   | |                 ------------- this is found to be of type `impl Future`
+LL | |
+LL | |         false => async_dummy2(),
+   | |                  ^^^^^^^^^^^^^^ expected opaque type, found a different opaque type
+...  |
+LL | |
+LL | |     };
+   | |_____- `match` arms have incompatible types
+   |
+   = note:     expected type `impl Future` (opaque type at <$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>)
+   = note: distinct uses of `impl Trait` result in different opaque types
+help: consider `await`ing on both `Future`s
+   |
+LL |         true => async_dummy().await,
+LL |
+LL |         false => async_dummy2().await,
+   |
+
+error[E0308]: `match` arms have incompatible types
+  --> $DIR/match-prev-arm-needing-semi.rs:11:18
+   |
+LL |       let _ = match true {
+   |  _____________-
+LL | |         true => {
+LL | |             dummy();
+   | |             --------
+   | |             |      |
+   | |             |      help: consider removing this semicolon
+   | |             this is found to be of type `()`
+LL | |
+LL | |         }
+LL | |         false => dummy(),
+   | |                  ^^^^^^^ expected `()`, found `i32`
+LL | |
+LL | |     };
+   | |_____- `match` arms have incompatible types
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/src/test/ui/suggestions/opaque-type-error.stderr b/src/test/ui/suggestions/opaque-type-error.stderr
index a7c2b82942f..d74076cbc9b 100644
--- a/src/test/ui/suggestions/opaque-type-error.stderr
+++ b/src/test/ui/suggestions/opaque-type-error.stderr
@@ -16,6 +16,12 @@ LL | |     }.await
    = note:     expected type `impl Future` (opaque type at <$DIR/opaque-type-error.rs:8:19>)
            found opaque type `impl Future` (opaque type at <$DIR/opaque-type-error.rs:12:19>)
    = note: distinct uses of `impl Trait` result in different opaque types
+help: consider `await`ing on both `Future`s
+   |
+LL |         thing_one().await
+LL |     } else {
+LL |         thing_two().await
+   |
 
 error: aborting due to previous error