…trait, r=compiler-errors

improve tip for inaccessible traits

Improve the tips when the candidate method is from an inaccessible trait.

For example:

```rs
mod m {
  trait Trait {
    fn f() {}
  }
  impl<T> Trait for T {}
}

fn main() {
  struct S;
  S::f();
}
```

The difference between before and now is:

```diff
error[E0599]: no function or associated item named `f` found for struct `S` in the current scope
  --> ./src/main.rs:88:6
   |
LL |   struct S;
   |   -------- function or associated item `f` not found for this struct
LL |   S::f();
   |      ^ function or associated item not found in `S`
   |
   = help: items from traits can only be used if the trait is implemented and in scope
- help: trait `Trait` which provides `f` is implemented but not in scope; perhaps you want to import it
+ help: trait `crate::m::Trait` which provides `f` is implemented but not reachable
   |
- LL + use crate::m::Trait;
   |
```

…trait, r=compiler-errors

improve tip for inaccessible traits

Improve the tips when the candidate method is from an inaccessible trait.

For example:

```rs
mod m {
  trait Trait {
    fn f() {}
  }
  impl<T> Trait for T {}
}

fn main() {
  struct S;
  S::f();
}
```

The difference between before and now is:

```diff
error[E0599]: no function or associated item named `f` found for struct `S` in the current scope
  --> ./src/main.rs:88:6
   |
LL |   struct S;
   |   -------- function or associated item `f` not found for this struct
LL |   S::f();
   |      ^ function or associated item not found in `S`
   |
   = help: items from traits can only be used if the trait is implemented and in scope
- help: trait `Trait` which provides `f` is implemented but not in scope; perhaps you want to import it
+ help: trait `crate::m::Trait` which provides `f` is implemented but not reachable
   |
- LL + use crate::m::Trait;
   |
```

…llaumeGomez

Rollup of 9 pull requests

Successful merges:

 - rust-lang#123782 (Test that opaque types can't have themselves as a hidden type with incompatible lifetimes)
 - rust-lang#124580 (Suggest removing unused tuple fields if they are the last fields)
 - rust-lang#125852 (improve tip for inaccessible traits)
 - rust-lang#126422 (Suggest using a standalone doctest for non-local impl defs)
 - rust-lang#126427 (Rewrite `intrinsic-unreachable`, `sepcomp-cci-copies`, `sepcomp-inlining` and `sepcomp-separate` `run-make` tests to rmake.rs)
 - rust-lang#126493 (safe transmute: support non-ZST, variantful, uninhabited enums)
 - rust-lang#126572 (override user defined channel when using precompiled rustc)
 - rust-lang#126615 (Add `rustc-ice*` to `.gitignore`)
 - rust-lang#126632 (Replace `move||` with `move ||`)

Failed merges:

 - rust-lang#126558 (hir_typeck: be more conservative in making "note caller chooses ty param" note)

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

…trait, r=compiler-errors

improve tip for inaccessible traits

Improve the tips when the candidate method is from an inaccessible trait.

For example:

```rs
mod m {
  trait Trait {
    fn f() {}
  }
  impl<T> Trait for T {}
}

fn main() {
  struct S;
  S::f();
}
```

The difference between before and now is:

```diff
error[E0599]: no function or associated item named `f` found for struct `S` in the current scope
  --> ./src/main.rs:88:6
   |
LL |   struct S;
   |   -------- function or associated item `f` not found for this struct
LL |   S::f();
   |      ^ function or associated item not found in `S`
   |
   = help: items from traits can only be used if the trait is implemented and in scope
- help: trait `Trait` which provides `f` is implemented but not in scope; perhaps you want to import it
+ help: trait `crate::m::Trait` which provides `f` is implemented but not reachable
   |
- LL + use crate::m::Trait;
   |
```