Auto merge of #72433 - RalfJung:rollup-srft8nx, r=RalfJung

Rollup of 7 pull requests

Successful merges:

 - #72055 (Intern predicates)
 - #72149 (Don't `type_of` on trait assoc ty without default)
 - #72347 (Make intra-link resolve links for both trait and impl items)
 - #72350 (Improve documentation of `slice::from_raw_parts`)
 - #72382 (Show default values for debug-assertions & debug-assertions-std)
 - #72421 (Fix anchor display when hovering impl)
 - #72425 (fix discriminant_value sign extension)

Failed merges:

r? @ghost

src/test/ui/issues/issue-72076.rs

@@ -0,0 +1,6 @@
+trait X {
+    type S;
+    fn f() -> Self::S {} //~ ERROR mismatched types
+}
+
+fn main() {}

src/test/ui/issues/issue-72076.stderr

@@ -0,0 +1,14 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-72076.rs:3:23
+   |
+LL |     fn f() -> Self::S {}
+   |                       ^^ expected associated type, found `()`
+   |
+   = note: expected associated type `<Self as X>::S`
+                    found unit type `()`
+   = help: consider constraining the associated type `<Self as X>::S` to `()` or calling a method that returns `<Self as X>::S`
+   = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.

src/test/ui/suggestions/trait-with-missing-associated-type-restriction.rs

@@ -7,6 +7,7 @@ trait Trait<T = Self> {
 
     fn func(&self) -> Self::A;
     fn funk(&self, _: Self::A);
+    fn funq(&self) -> Self::A {} //~ ERROR mismatched types
 }
 
 fn foo(_: impl Trait, x: impl Trait) {

src/test/ui/suggestions/trait-with-missing-associated-type-restriction.stderr

@@ -1,5 +1,19 @@
 error[E0308]: mismatched types
-  --> $DIR/trait-with-missing-associated-type-restriction.rs:13:9
+  --> $DIR/trait-with-missing-associated-type-restriction.rs:10:31
+   |
+LL |     fn funq(&self) -> Self::A {}
+   |                               ^^ expected associated type, found `()`
+   |
+   = note: expected associated type `<Self as Trait<T>>::A`
+                    found unit type `()`
+help: a method is available that returns `<Self as Trait<T>>::A`
+  --> $DIR/trait-with-missing-associated-type-restriction.rs:8:5
+   |
+LL |     fn func(&self) -> Self::A;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ consider calling `Trait::func`
+
+error[E0308]: mismatched types
+  --> $DIR/trait-with-missing-associated-type-restriction.rs:14:9
    |
 LL |     qux(x.func())
    |         ^^^^^^^^ expected `usize`, found associated type
@@ -12,7 +26,7 @@ LL | fn foo(_: impl Trait, x: impl Trait<A = usize>) {
    |                                    ^^^^^^^^^^^
 
 error[E0308]: mismatched types
-  --> $DIR/trait-with-missing-associated-type-restriction.rs:17:9
+  --> $DIR/trait-with-missing-associated-type-restriction.rs:18:9
    |
 LL |     qux(x.func())
    |         ^^^^^^^^ expected `usize`, found associated type
@@ -25,7 +39,7 @@ LL | fn bar<T: Trait<A = usize>>(x: T) {
    |                ^^^^^^^^^^^
 
 error[E0308]: mismatched types
-  --> $DIR/trait-with-missing-associated-type-restriction.rs:21:9
+  --> $DIR/trait-with-missing-associated-type-restriction.rs:22:9
    |
 LL |     qux(x.func())
    |         ^^^^^^^^ expected `usize`, found associated type
@@ -38,25 +52,28 @@ LL | fn foo2(x: impl Trait<i32, A = usize>) {
    |                          ^^^^^^^^^^^
 
 error[E0308]: mismatched types
-  --> $DIR/trait-with-missing-associated-type-restriction.rs:25:12
+  --> $DIR/trait-with-missing-associated-type-restriction.rs:26:12
    |
 LL |     x.funk(3);
    |            ^ expected associated type, found integer
    |
    = note: expected associated type `<T as Trait<i32>>::A`
                          found type `{integer}`
-help: a method is available that returns `<T as Trait<i32>>::A`
+help: some methods are available that return `<T as Trait<i32>>::A`
   --> $DIR/trait-with-missing-associated-type-restriction.rs:8:5
    |
 LL |     fn func(&self) -> Self::A;
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ consider calling `Trait::func`
+LL |     fn funk(&self, _: Self::A);
+LL |     fn funq(&self) -> Self::A {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^ consider calling `Trait::funq`
 help: consider constraining the associated type `<T as Trait<i32>>::A` to `{integer}`
    |
 LL | fn bar2<T: Trait<i32, A = {integer}>>(x: T) {
    |                     ^^^^^^^^^^^^^^^
 
 error[E0308]: mismatched types
-  --> $DIR/trait-with-missing-associated-type-restriction.rs:26:9
+  --> $DIR/trait-with-missing-associated-type-restriction.rs:27:9
    |
 LL |     qux(x.func())
    |         ^^^^^^^^ expected `usize`, found associated type
@@ -69,7 +86,7 @@ LL | fn bar2<T: Trait<i32, A = usize>>(x: T) {
    |                     ^^^^^^^^^^^
 
 error[E0308]: mismatched types
-  --> $DIR/trait-with-missing-associated-type-restriction.rs:30:9
+  --> $DIR/trait-with-missing-associated-type-restriction.rs:31:9
    |
 LL | fn baz<D: std::fmt::Debug, T: Trait<A = D>>(x: T) {
    |        - this type parameter
@@ -80,13 +97,13 @@ LL |     qux(x.func())
            found type parameter `D`
 
 error[E0308]: mismatched types
-  --> $DIR/trait-with-missing-associated-type-restriction.rs:34:9
+  --> $DIR/trait-with-missing-associated-type-restriction.rs:35:9
    |
 LL |     qux(x.func())
    |         ^^^^^^^^ expected `usize`, found `()`
 
 error[E0308]: mismatched types
-  --> $DIR/trait-with-missing-associated-type-restriction.rs:38:9
+  --> $DIR/trait-with-missing-associated-type-restriction.rs:39:9
    |
 LL |     qux(x.func())
    |         ^^^^^^^^ expected `usize`, found associated type
@@ -98,6 +115,6 @@ help: consider constraining the associated type `<T as Trait>::A` to `usize`
 LL | fn ban<T>(x: T) where T: Trait<A = usize> {
    |                               ^^^^^^^^^^^
 
-error: aborting due to 8 previous errors
+error: aborting due to 9 previous errors
 
 For more information about this error, try `rustc --explain E0308`.