Auto merge of #97135 - Dylan-DPC:rollup-06u9pqn, r=Dylan-DPC

Rollup of 6 pull requests

Successful merges:

 - #94639 (Suggest dereferencing non-lval mutable reference on assignment)
 - #95979 (update coherence docs, fix generator + opaque type ICE)
 - #96378 (Mention traits and types involved in unstable trait upcasting)
 - #96917 (Make HashMap fall back to RtlGenRandom if BCryptGenRandom fails)
 - #97101 (Add tracking issue for ExitCode::exit_process)
 - #97123 (Clean fix for #96223)

Failed merges:

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

17 files changed, 272 insertions, 19 deletions

diff --git a/src/test/ui/binop/issue-77910-1.stderr b/src/test/ui/binop/issue-77910-1.stderr
index 95ee51a8826..68303b84208 100644
--- a/src/test/ui/binop/issue-77910-1.stderr
+++ b/src/test/ui/binop/issue-77910-1.stderr
@@ -12,20 +12,14 @@ LL |     assert_eq!(foo, y);
 error[E0277]: `for<'r> fn(&'r i32) -> &'r i32 {foo}` doesn't implement `Debug`
   --> $DIR/issue-77910-1.rs:8:5
    |
+LL | fn foo(s: &i32) -> &i32 {
+   |    --- consider calling this function
+...
 LL |     assert_eq!(foo, y);
    |     ^^^^^^^^^^^^^^^^^^ `for<'r> fn(&'r i32) -> &'r i32 {foo}` cannot be formatted using `{:?}` because it doesn't implement `Debug`
    |
    = help: the trait `Debug` is not implemented for `for<'r> fn(&'r i32) -> &'r i32 {foo}`
-   = help: the following other types implement trait `Debug`:
-             extern "C" fn() -> Ret
-             extern "C" fn(A) -> Ret
-             extern "C" fn(A, ...) -> Ret
-             extern "C" fn(A, B) -> Ret
-             extern "C" fn(A, B, ...) -> Ret
-             extern "C" fn(A, B, C) -> Ret
-             extern "C" fn(A, B, C, ...) -> Ret
-             extern "C" fn(A, B, C, D) -> Ret
-           and 68 others
+   = help: use parentheses to call the function: `foo(s)`
    = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 2 previous errors
diff --git a/src/test/ui/coherence/coherence-with-closure.rs b/src/test/ui/coherence/coherence-with-closure.rs
new file mode 100644
index 00000000000..6e3281d8508
--- /dev/null
+++ b/src/test/ui/coherence/coherence-with-closure.rs
@@ -0,0 +1,15 @@
+// Test that encountering closures during coherence does not cause issues.
+#![feature(type_alias_impl_trait)]
+type OpaqueClosure = impl Sized;
+fn defining_use() -> OpaqueClosure {
+    || ()
+}
+
+struct Wrapper<T>(T);
+trait Trait {}
+impl Trait for Wrapper<OpaqueClosure> {}
+//~^ ERROR cannot implement trait on type alias impl trait
+impl<T: Sync> Trait for Wrapper<T> {}
+//~^ ERROR conflicting implementations of trait `Trait` for type `Wrapper<OpaqueClosure>`
+
+fn main() {}
diff --git a/src/test/ui/coherence/coherence-with-closure.stderr b/src/test/ui/coherence/coherence-with-closure.stderr
new file mode 100644
index 00000000000..20b986cee69
--- /dev/null
+++ b/src/test/ui/coherence/coherence-with-closure.stderr
@@ -0,0 +1,24 @@
+error: cannot implement trait on type alias impl trait
+  --> $DIR/coherence-with-closure.rs:10:24
+   |
+LL | impl Trait for Wrapper<OpaqueClosure> {}
+   |                        ^^^^^^^^^^^^^
+   |
+note: type alias impl trait defined here
+  --> $DIR/coherence-with-closure.rs:3:22
+   |
+LL | type OpaqueClosure = impl Sized;
+   |                      ^^^^^^^^^^
+
+error[E0119]: conflicting implementations of trait `Trait` for type `Wrapper<OpaqueClosure>`
+  --> $DIR/coherence-with-closure.rs:12:1
+   |
+LL | impl Trait for Wrapper<OpaqueClosure> {}
+   | ------------------------------------- first implementation here
+LL |
+LL | impl<T: Sync> Trait for Wrapper<T> {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `Wrapper<OpaqueClosure>`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0119`.
diff --git a/src/test/ui/coherence/coherence-with-generator.rs b/src/test/ui/coherence/coherence-with-generator.rs
new file mode 100644
index 00000000000..d34c391db9f
--- /dev/null
+++ b/src/test/ui/coherence/coherence-with-generator.rs
@@ -0,0 +1,19 @@
+// Test that encountering closures during coherence does not cause issues.
+#![feature(type_alias_impl_trait, generators)]
+type OpaqueGenerator = impl Sized;
+fn defining_use() -> OpaqueGenerator {
+    || {
+        for i in 0..10 {
+            yield i;
+        }
+    }
+}
+
+struct Wrapper<T>(T);
+trait Trait {}
+impl Trait for Wrapper<OpaqueGenerator> {}
+//~^ ERROR cannot implement trait on type alias impl trait
+impl<T: Sync> Trait for Wrapper<T> {}
+//~^ ERROR conflicting implementations of trait `Trait` for type `Wrapper<OpaqueGenerator>`
+
+fn main() {}
diff --git a/src/test/ui/coherence/coherence-with-generator.stderr b/src/test/ui/coherence/coherence-with-generator.stderr
new file mode 100644
index 00000000000..249ad3cb9ec
--- /dev/null
+++ b/src/test/ui/coherence/coherence-with-generator.stderr
@@ -0,0 +1,24 @@
+error: cannot implement trait on type alias impl trait
+  --> $DIR/coherence-with-generator.rs:14:24
+   |
+LL | impl Trait for Wrapper<OpaqueGenerator> {}
+   |                        ^^^^^^^^^^^^^^^
+   |
+note: type alias impl trait defined here
+  --> $DIR/coherence-with-generator.rs:3:24
+   |
+LL | type OpaqueGenerator = impl Sized;
+   |                        ^^^^^^^^^^
+
+error[E0119]: conflicting implementations of trait `Trait` for type `Wrapper<OpaqueGenerator>`
+  --> $DIR/coherence-with-generator.rs:16:1
+   |
+LL | impl Trait for Wrapper<OpaqueGenerator> {}
+   | --------------------------------------- first implementation here
+LL |
+LL | impl<T: Sync> Trait for Wrapper<T> {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `Wrapper<OpaqueGenerator>`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0119`.
diff --git a/src/test/ui/feature-gates/feature-gate-trait_upcasting.stderr b/src/test/ui/feature-gates/feature-gate-trait_upcasting.stderr
index bc13a5d7d7b..93afa78459d 100644
--- a/src/test/ui/feature-gates/feature-gate-trait_upcasting.stderr
+++ b/src/test/ui/feature-gates/feature-gate-trait_upcasting.stderr
@@ -1,4 +1,4 @@
-error[E0658]: trait upcasting coercion is experimental
+error[E0658]: cannot cast `dyn Bar` to `dyn Foo`, trait upcasting coercion is experimental
   --> $DIR/feature-gate-trait_upcasting.rs:11:25
    |
 LL |     let foo: &dyn Foo = bar;
@@ -6,6 +6,7 @@ LL |     let foo: &dyn Foo = bar;
    |
    = note: see issue #65991 <https://github.com/rust-lang/rust/issues/65991> for more information
    = help: add `#![feature(trait_upcasting)]` to the crate attributes to enable
+   = note: required when coercing `&dyn Bar` into `&dyn Foo`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-11515.stderr b/src/test/ui/issues/issue-11515.stderr
index a70e7c416bc..17bfae2a4e4 100644
--- a/src/test/ui/issues/issue-11515.stderr
+++ b/src/test/ui/issues/issue-11515.stderr
@@ -1,4 +1,4 @@
-error[E0658]: trait upcasting coercion is experimental
+error[E0658]: cannot cast `dyn Fn()` to `dyn FnMut()`, trait upcasting coercion is experimental
   --> $DIR/issue-11515.rs:9:33
    |
 LL |     let test = box Test { func: closure };
@@ -6,6 +6,7 @@ LL |     let test = box Test { func: closure };
    |
    = note: see issue #65991 <https://github.com/rust-lang/rust/issues/65991> for more information
    = help: add `#![feature(trait_upcasting)]` to the crate attributes to enable
+   = note: required when coercing `Box<(dyn Fn() + 'static)>` into `Box<(dyn FnMut() + 'static)>`
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-5239-1.stderr b/src/test/ui/issues/issue-5239-1.stderr
index b743f0df4b1..f53ddb95416 100644
--- a/src/test/ui/issues/issue-5239-1.stderr
+++ b/src/test/ui/issues/issue-5239-1.stderr
@@ -5,11 +5,6 @@ LL |     let x = |ref x: isize| { x += 1; };
    |                              -^^^^^
    |                              |
    |                              cannot use `+=` on type `&isize`
-   |
-help: `+=` can be used on `isize`, you can dereference `x`
-   |
-LL |     let x = |ref x: isize| { *x += 1; };
-   |                              +
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/suggestions/imm-ref-trait-object-literal-bound-regions.stderr b/src/test/ui/suggestions/imm-ref-trait-object-literal-bound-regions.stderr
index 0783f04dc9b..ba6af8f15fa 100644
--- a/src/test/ui/suggestions/imm-ref-trait-object-literal-bound-regions.stderr
+++ b/src/test/ui/suggestions/imm-ref-trait-object-literal-bound-regions.stderr
@@ -5,6 +5,7 @@ LL |     foo::<S>(s);
    |     ^^^^^^^^ the trait `for<'b> Trait` is not implemented for `&'b S`
    |
    = help: the trait `Trait` is implemented for `&'a mut S`
+   = note: `for<'b> Trait` is implemented for `&'b mut S`, but not for `&'b S`
 note: required by a bound in `foo`
   --> $DIR/imm-ref-trait-object-literal-bound-regions.rs:11:20
    |
diff --git a/src/test/ui/suggestions/mut-ref-reassignment.stderr b/src/test/ui/suggestions/mut-ref-reassignment.stderr
index 3bd98c76307..b3cb6dd0614 100644
--- a/src/test/ui/suggestions/mut-ref-reassignment.stderr
+++ b/src/test/ui/suggestions/mut-ref-reassignment.stderr
@@ -8,7 +8,7 @@ LL |     opt = None;
    |
    = note: expected mutable reference `&mut Option<String>`
                            found enum `Option<_>`
-help: consider dereferencing here to assign to the mutable borrowed piece of memory
+help: consider dereferencing here to assign to the mutably borrowed value
    |
 LL |     *opt = None;
    |     +
@@ -34,7 +34,7 @@ LL |     opt = Some(String::new())
    |
    = note: expected mutable reference `&mut Option<String>`
                            found enum `Option<String>`
-help: consider dereferencing here to assign to the mutable borrowed piece of memory
+help: consider dereferencing here to assign to the mutably borrowed value
    |
 LL |     *opt = Some(String::new())
    |     +
diff --git a/src/test/ui/typeck/assign-non-lval-derefmut.fixed b/src/test/ui/typeck/assign-non-lval-derefmut.fixed
new file mode 100644
index 00000000000..0c23199af22
--- /dev/null
+++ b/src/test/ui/typeck/assign-non-lval-derefmut.fixed
@@ -0,0 +1,15 @@
+// run-rustfix
+
+fn main() {
+    let x = std::sync::Mutex::new(1usize);
+    *x.lock().unwrap() = 2;
+    //~^ ERROR invalid left-hand side of assignment
+    *x.lock().unwrap() += 1;
+    //~^ ERROR binary assignment operation `+=` cannot be applied to type `MutexGuard<'_, usize>`
+
+    let mut y = x.lock().unwrap();
+    *y = 2;
+    //~^ ERROR mismatched types
+    *y += 1;
+    //~^ ERROR binary assignment operation `+=` cannot be applied to type `MutexGuard<'_, usize>`
+}
diff --git a/src/test/ui/typeck/assign-non-lval-derefmut.rs b/src/test/ui/typeck/assign-non-lval-derefmut.rs
new file mode 100644
index 00000000000..ec1882f5271
--- /dev/null
+++ b/src/test/ui/typeck/assign-non-lval-derefmut.rs
@@ -0,0 +1,15 @@
+// run-rustfix
+
+fn main() {
+    let x = std::sync::Mutex::new(1usize);
+    x.lock().unwrap() = 2;
+    //~^ ERROR invalid left-hand side of assignment
+    x.lock().unwrap() += 1;
+    //~^ ERROR binary assignment operation `+=` cannot be applied to type `MutexGuard<'_, usize>`
+
+    let mut y = x.lock().unwrap();
+    y = 2;
+    //~^ ERROR mismatched types
+    y += 1;
+    //~^ ERROR binary assignment operation `+=` cannot be applied to type `MutexGuard<'_, usize>`
+}
diff --git a/src/test/ui/typeck/assign-non-lval-derefmut.stderr b/src/test/ui/typeck/assign-non-lval-derefmut.stderr
new file mode 100644
index 00000000000..a6fcdfe21f4
--- /dev/null
+++ b/src/test/ui/typeck/assign-non-lval-derefmut.stderr
@@ -0,0 +1,58 @@
+error[E0070]: invalid left-hand side of assignment
+  --> $DIR/assign-non-lval-derefmut.rs:5:23
+   |
+LL |     x.lock().unwrap() = 2;
+   |     ----------------- ^
+   |     |
+   |     cannot assign to this expression
+   |
+help: consider dereferencing here to assign to the mutably borrowed value
+   |
+LL |     *x.lock().unwrap() = 2;
+   |     +
+
+error[E0368]: binary assignment operation `+=` cannot be applied to type `MutexGuard<'_, usize>`
+  --> $DIR/assign-non-lval-derefmut.rs:7:5
+   |
+LL |     x.lock().unwrap() += 1;
+   |     -----------------^^^^^
+   |     |
+   |     cannot use `+=` on type `MutexGuard<'_, usize>`
+   |
+help: `+=` can be used on `usize`, you can dereference `x.lock().unwrap()`
+   |
+LL |     *x.lock().unwrap() += 1;
+   |     +
+
+error[E0308]: mismatched types
+  --> $DIR/assign-non-lval-derefmut.rs:11:9
+   |
+LL |     let mut y = x.lock().unwrap();
+   |                 ----------------- expected due to this value
+LL |     y = 2;
+   |         ^ expected struct `MutexGuard`, found integer
+   |
+   = note: expected struct `MutexGuard<'_, usize>`
+                found type `{integer}`
+help: consider dereferencing here to assign to the mutably borrowed value
+   |
+LL |     *y = 2;
+   |     +
+
+error[E0368]: binary assignment operation `+=` cannot be applied to type `MutexGuard<'_, usize>`
+  --> $DIR/assign-non-lval-derefmut.rs:13:5
+   |
+LL |     y += 1;
+   |     -^^^^^
+   |     |
+   |     cannot use `+=` on type `MutexGuard<'_, usize>`
+   |
+help: `+=` can be used on `usize`, you can dereference `y`
+   |
+LL |     *y += 1;
+   |     +
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0070, E0308, E0368.
+For more information about an error, try `rustc --explain E0070`.
diff --git a/src/test/ui/typeck/assign-non-lval-mut-ref.fixed b/src/test/ui/typeck/assign-non-lval-mut-ref.fixed
new file mode 100644
index 00000000000..10c7b9dbfb3
--- /dev/null
+++ b/src/test/ui/typeck/assign-non-lval-mut-ref.fixed
@@ -0,0 +1,15 @@
+// run-rustfix
+
+fn main() {
+    let mut x = vec![1usize];
+    *x.last_mut().unwrap() = 2;
+    //~^ ERROR invalid left-hand side of assignment
+    *x.last_mut().unwrap() += 1;
+    //~^ ERROR binary assignment operation `+=` cannot be applied to type `&mut usize`
+
+    let y = x.last_mut().unwrap();
+    *y = 2;
+    //~^ ERROR mismatched types
+    *y += 1;
+    //~^ ERROR binary assignment operation `+=` cannot be applied to type `&mut usize`
+}
diff --git a/src/test/ui/typeck/assign-non-lval-mut-ref.rs b/src/test/ui/typeck/assign-non-lval-mut-ref.rs
new file mode 100644
index 00000000000..bceff0ef09d
--- /dev/null
+++ b/src/test/ui/typeck/assign-non-lval-mut-ref.rs
@@ -0,0 +1,15 @@
+// run-rustfix
+
+fn main() {
+    let mut x = vec![1usize];
+    x.last_mut().unwrap() = 2;
+    //~^ ERROR invalid left-hand side of assignment
+    x.last_mut().unwrap() += 1;
+    //~^ ERROR binary assignment operation `+=` cannot be applied to type `&mut usize`
+
+    let y = x.last_mut().unwrap();
+    y = 2;
+    //~^ ERROR mismatched types
+    y += 1;
+    //~^ ERROR binary assignment operation `+=` cannot be applied to type `&mut usize`
+}
diff --git a/src/test/ui/typeck/assign-non-lval-mut-ref.stderr b/src/test/ui/typeck/assign-non-lval-mut-ref.stderr
new file mode 100644
index 00000000000..be2e9fe95e8
--- /dev/null
+++ b/src/test/ui/typeck/assign-non-lval-mut-ref.stderr
@@ -0,0 +1,56 @@
+error[E0070]: invalid left-hand side of assignment
+  --> $DIR/assign-non-lval-mut-ref.rs:5:27
+   |
+LL |     x.last_mut().unwrap() = 2;
+   |     --------------------- ^
+   |     |
+   |     cannot assign to this expression
+   |
+help: consider dereferencing here to assign to the mutably borrowed value
+   |
+LL |     *x.last_mut().unwrap() = 2;
+   |     +
+
+error[E0368]: binary assignment operation `+=` cannot be applied to type `&mut usize`
+  --> $DIR/assign-non-lval-mut-ref.rs:7:5
+   |
+LL |     x.last_mut().unwrap() += 1;
+   |     ---------------------^^^^^
+   |     |
+   |     cannot use `+=` on type `&mut usize`
+   |
+help: `+=` can be used on `usize`, you can dereference `x.last_mut().unwrap()`
+   |
+LL |     *x.last_mut().unwrap() += 1;
+   |     +
+
+error[E0308]: mismatched types
+  --> $DIR/assign-non-lval-mut-ref.rs:11:9
+   |
+LL |     let y = x.last_mut().unwrap();
+   |             --------------------- expected due to this value
+LL |     y = 2;
+   |         ^ expected `&mut usize`, found integer
+   |
+help: consider dereferencing here to assign to the mutably borrowed value
+   |
+LL |     *y = 2;
+   |     +
+
+error[E0368]: binary assignment operation `+=` cannot be applied to type `&mut usize`
+  --> $DIR/assign-non-lval-mut-ref.rs:13:5
+   |
+LL |     y += 1;
+   |     -^^^^^
+   |     |
+   |     cannot use `+=` on type `&mut usize`
+   |
+help: `+=` can be used on `usize`, you can dereference `y`
+   |
+LL |     *y += 1;
+   |     +
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0070, E0308, E0368.
+For more information about an error, try `rustc --explain E0070`.
diff --git a/src/test/ui/typeck/issue-93486.stderr b/src/test/ui/typeck/issue-93486.stderr
index 70b5b63f1cb..167edc8942a 100644
--- a/src/test/ui/typeck/issue-93486.stderr
+++ b/src/test/ui/typeck/issue-93486.stderr
@@ -5,6 +5,11 @@ LL |         vec![].last_mut().unwrap() = 3_u8;
    |         -------------------------- ^
    |         |
    |         cannot assign to this expression
+   |
+help: consider dereferencing here to assign to the mutably borrowed value
+   |
+LL |         *vec![].last_mut().unwrap() = 3_u8;
+   |         +
 
 error: aborting due to previous error