Auto merge of #132128 - workingjubilee:rollup-uwqp2i2, r=workingjubilee

Rollup of 4 pull requests

Successful merges:

 - #131457 (Expand `ptr::fn_addr_eq()` documentation.)
 - #132085 (Update StableMIR doc to reflect current status)
 - #132118 (Add support for `~const` item bounds)
 - #132125 (coverage: Emit LLVM intrinsics using the normal helper method)

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

tests/ui/traits/const-traits/assoc-type-const-bound-usage-0.rs

@@ -1,5 +1,5 @@
 //@ compile-flags: -Znext-solver
-//@ known-bug: unknown
+//@ check-pass
 
 #![allow(incomplete_features)]
 #![feature(const_trait_impl, effects)]

tests/ui/traits/const-traits/assoc-type-const-bound-usage-0.stderr

@@ -1,15 +0,0 @@
-error[E0271]: type mismatch resolving `<T as Trait>::Assoc == T`
-  --> $DIR/assoc-type-const-bound-usage-0.rs:14:5
-   |
-LL |     T::Assoc::func()
-   |     ^^^^^^^^^^^^^^^^ types differ
-
-error[E0271]: type mismatch resolving `<T as Trait>::Assoc == T`
-  --> $DIR/assoc-type-const-bound-usage-0.rs:18:5
-   |
-LL |     <T as Trait>::Assoc::func()
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ types differ
-
-error: aborting due to 2 previous errors
-
-For more information about this error, try `rustc --explain E0271`.

tests/ui/traits/const-traits/assoc-type-const-bound-usage-1.stderr

@@ -6,18 +6,30 @@ LL | #![feature(const_trait_impl, effects, generic_const_exprs)]
    |
    = help: remove one of these features
 
-error[E0271]: type mismatch resolving `<T as Trait>::Assoc == T`
-  --> $DIR/assoc-type-const-bound-usage-1.rs:15:44
+error[E0284]: type annotations needed: cannot normalize `unqualified<T>::{constant#0}`
+  --> $DIR/assoc-type-const-bound-usage-1.rs:15:37
    |
 LL | fn unqualified<T: const Trait>() -> Type<{ T::Assoc::func() }> {
-   |                                            ^^^^^^^^^^^^^^^^ types differ
+   |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot normalize `unqualified<T>::{constant#0}`
 
-error[E0271]: type mismatch resolving `<T as Trait>::Assoc == T`
-  --> $DIR/assoc-type-const-bound-usage-1.rs:19:42
+error[E0284]: type annotations needed: cannot normalize `qualified<T>::{constant#0}`
+  --> $DIR/assoc-type-const-bound-usage-1.rs:19:35
    |
 LL | fn qualified<T: const Trait>() -> Type<{ <T as Trait>::Assoc::func() }> {
-   |                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^ types differ
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot normalize `qualified<T>::{constant#0}`
 
-error: aborting due to 3 previous errors
+error[E0284]: type annotations needed: cannot normalize `unqualified<T>::{constant#0}`
+  --> $DIR/assoc-type-const-bound-usage-1.rs:16:5
+   |
+LL |     Type
+   |     ^^^^ cannot normalize `unqualified<T>::{constant#0}`
 
-For more information about this error, try `rustc --explain E0271`.
+error[E0284]: type annotations needed: cannot normalize `qualified<T>::{constant#0}`
+  --> $DIR/assoc-type-const-bound-usage-1.rs:20:5
+   |
+LL |     Type
+   |     ^^^^ cannot normalize `qualified<T>::{constant#0}`
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0284`.

tests/ui/traits/const-traits/assoc-type-const-bound-usage-fail-2.rs

@@ -0,0 +1,35 @@
+//@ compile-flags: -Znext-solver
+
+// Check that `~const` item bounds only hold if the where clauses on the
+// associated type are also const.
+// i.e. check that we validate the const conditions for the associated type
+// when considering one of implied const bounds.
+
+#![allow(incomplete_features)]
+#![feature(const_trait_impl, effects)]
+
+#[const_trait]
+trait Trait {
+    type Assoc<U>: ~const Trait
+    where
+        U: ~const Other;
+
+    fn func();
+}
+
+#[const_trait]
+trait Other {}
+
+const fn fails<T: ~const Trait, U: Other>() {
+    T::Assoc::<U>::func();
+    //~^ ERROR the trait bound `<T as Trait>::Assoc<U>: ~const Trait` is not satisfied
+    <T as Trait>::Assoc::<U>::func();
+    //~^ ERROR the trait bound `<T as Trait>::Assoc<U>: ~const Trait` is not satisfied
+}
+
+const fn works<T: ~const Trait, U: ~const Other>() {
+    T::Assoc::<U>::func();
+    <T as Trait>::Assoc::<U>::func();
+}
+
+fn main() {}

tests/ui/traits/const-traits/assoc-type-const-bound-usage-fail-2.stderr

@@ -0,0 +1,15 @@
+error[E0277]: the trait bound `<T as Trait>::Assoc<U>: ~const Trait` is not satisfied
+  --> $DIR/assoc-type-const-bound-usage-fail-2.rs:24:5
+   |
+LL |     T::Assoc::<U>::func();
+   |     ^^^^^^^^^^^^^^^^^^^^^
+
+error[E0277]: the trait bound `<T as Trait>::Assoc<U>: ~const Trait` is not satisfied
+  --> $DIR/assoc-type-const-bound-usage-fail-2.rs:26:5
+   |
+LL |     <T as Trait>::Assoc::<U>::func();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.

tests/ui/traits/const-traits/assoc-type-const-bound-usage-fail.rs

@@ -0,0 +1,28 @@
+//@ compile-flags: -Znext-solver
+
+// Check that `~const` item bounds only hold if the parent trait is `~const`.
+// i.e. check that we validate the const conditions for the associated type
+// when considering one of implied const bounds.
+
+#![allow(incomplete_features)]
+#![feature(const_trait_impl, effects)]
+
+#[const_trait]
+trait Trait {
+    type Assoc: ~const Trait;
+    fn func();
+}
+
+const fn unqualified<T: Trait>() {
+    T::Assoc::func();
+    //~^ ERROR the trait bound `T: ~const Trait` is not satisfied
+    <T as Trait>::Assoc::func();
+    //~^ ERROR the trait bound `T: ~const Trait` is not satisfied
+}
+
+const fn works<T: ~const Trait>() {
+    T::Assoc::func();
+    <T as Trait>::Assoc::func();
+}
+
+fn main() {}

tests/ui/traits/const-traits/assoc-type-const-bound-usage-fail.stderr

@@ -0,0 +1,15 @@
+error[E0277]: the trait bound `T: ~const Trait` is not satisfied
+  --> $DIR/assoc-type-const-bound-usage-fail.rs:17:5
+   |
+LL |     T::Assoc::func();
+   |     ^^^^^^^^^^^^^^^^
+
+error[E0277]: the trait bound `T: ~const Trait` is not satisfied
+  --> $DIR/assoc-type-const-bound-usage-fail.rs:19:5
+   |
+LL |     <T as Trait>::Assoc::func();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.