…r=oli-obk

Use root obligation on E0277 for some cases

When encountering trait bound errors that satisfy some heuristics that tell us that the relevant trait for the user comes from the root obligation and not the current obligation, we use the root predicate for the main message.

This allows to talk about "X doesn't implement Pattern<'_>" over the most specific case that just happened to fail, like  "char doesn't implement Fn(&mut char)" in
`tests/ui/traits/suggest-dereferences/root-obligation.rs`

The heuristics are:

 - the type of the leaf predicate is (roughly) the same as the type from the root predicate, as a proxy for "we care about the root"
 - the leaf trait and the root trait are different, so as to avoid talking about `&mut T: Trait` and instead remain talking about `T: Trait` instead
 - the root trait is not `Unsize`, as to avoid talking about it in `tests/ui/coercion/coerce-issue-49593-box-never.rs`.

```
error[E0277]: the trait bound `&char: Pattern<'_>` is not satisfied
  --> $DIR/root-obligation.rs:6:38
   |
LL |         .filter(|c| "aeiou".contains(c))
   |                             -------- ^ the trait `Fn<(char,)>` is not implemented for `&char`, which is required by `&char: Pattern<'_>`
   |                             |
   |                             required by a bound introduced by this call
   |
   = note: required for `&char` to implement `FnOnce<(char,)>`
   = note: required for `&char` to implement `Pattern<'_>`
note: required by a bound in `core::str::<impl str>::contains`
  --> $SRC_DIR/core/src/str/mod.rs:LL:COL
help: consider dereferencing here
   |
LL |         .filter(|c| "aeiou".contains(*c))
   |                                      +
```

Fix rust-lang#79359, fix rust-lang#119983, fix rust-lang#118779, cc rust-lang#118415 (the suggestion needs to change), cc rust-lang#121398 (doesn't fix the underlying issue).

…llaumeGomez

Rollup of 9 pull requests

Successful merges:

 - rust-lang#120976 (constify a couple thread_local statics)
 - rust-lang#121576 (Convert the rest of the visitors to use `VisitorResult`)
 - rust-lang#121826 (Use root obligation on E0277 for some cases)
 - rust-lang#121928 (Extract an arguments struct for `Builder::then_else_break`)
 - rust-lang#121958 (Fix redundant import errors for preload extern crate)
 - rust-lang#121959 (Removing absolute path in proc-macro)
 - rust-lang#121968 (Don't run test_get_os_named_thread on win7)
 - rust-lang#121977 (Doc: Fix incorrect reference to integer in Atomic{Ptr,Bool}::as_ptr.)
 - rust-lang#121978 (Fix duplicated path in the "not found dylib" error)

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

…r=oli-obk

Use root obligation on E0277 for some cases

When encountering trait bound errors that satisfy some heuristics that tell us that the relevant trait for the user comes from the root obligation and not the current obligation, we use the root predicate for the main message.

This allows to talk about "X doesn't implement Pattern<'_>" over the most specific case that just happened to fail, like  "char doesn't implement Fn(&mut char)" in
`tests/ui/traits/suggest-dereferences/root-obligation.rs`

The heuristics are:

 - the type of the leaf predicate is (roughly) the same as the type from the root predicate, as a proxy for "we care about the root"
 - the leaf trait and the root trait are different, so as to avoid talking about `&mut T: Trait` and instead remain talking about `T: Trait` instead
 - the root trait is not `Unsize`, as to avoid talking about it in `tests/ui/coercion/coerce-issue-49593-box-never.rs`.

```
error[E0277]: the trait bound `&char: Pattern<'_>` is not satisfied
  --> $DIR/root-obligation.rs:6:38
   |
LL |         .filter(|c| "aeiou".contains(c))
   |                             -------- ^ the trait `Fn<(char,)>` is not implemented for `&char`, which is required by `&char: Pattern<'_>`
   |                             |
   |                             required by a bound introduced by this call
   |
   = note: required for `&char` to implement `FnOnce<(char,)>`
   = note: required for `&char` to implement `Pattern<'_>`
note: required by a bound in `core::str::<impl str>::contains`
  --> $SRC_DIR/core/src/str/mod.rs:LL:COL
help: consider dereferencing here
   |
LL |         .filter(|c| "aeiou".contains(*c))
   |                                      +
```

Fix rust-lang#79359, fix rust-lang#119983, fix rust-lang#118779, cc rust-lang#118415 (the suggestion needs to change), cc rust-lang#121398 (doesn't fix the underlying issue).

…iaskrgr

Rollup of 10 pull requests

Successful merges:

 - rust-lang#121213 (Add an example to demonstrate how Rc::into_inner works)
 - rust-lang#121262 (Add vector time complexity)
 - rust-lang#121287 (Clarify/add `must_use` message for Rc/Arc/Weak::into_raw.)
 - rust-lang#121664 (Adjust error `yield`/`await` lowering)
 - rust-lang#121826 (Use root obligation on E0277 for some cases)
 - rust-lang#121838 (Use the correct logic for nested impl trait in assoc types)
 - rust-lang#121913 (Don't panic when waiting on poisoned queries)
 - rust-lang#121987 (pattern analysis: abort on arity mismatch)
 - rust-lang#121993 (Avoid using unnecessary queries when printing the query stack in panics)
 - rust-lang#121997 (interpret/cast: make more matches on FloatTy properly exhaustive)

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

Rollup merge of rust-lang#121826 - estebank:e0277-root-obligation-2, r=oli-obk

Use root obligation on E0277 for some cases

When encountering trait bound errors that satisfy some heuristics that tell us that the relevant trait for the user comes from the root obligation and not the current obligation, we use the root predicate for the main message.

This allows to talk about "X doesn't implement Pattern<'_>" over the most specific case that just happened to fail, like  "char doesn't implement Fn(&mut char)" in
`tests/ui/traits/suggest-dereferences/root-obligation.rs`

The heuristics are:

 - the type of the leaf predicate is (roughly) the same as the type from the root predicate, as a proxy for "we care about the root"
 - the leaf trait and the root trait are different, so as to avoid talking about `&mut T: Trait` and instead remain talking about `T: Trait` instead
 - the root trait is not `Unsize`, as to avoid talking about it in `tests/ui/coercion/coerce-issue-49593-box-never.rs`.

```
error[E0277]: the trait bound `&char: Pattern<'_>` is not satisfied
  --> $DIR/root-obligation.rs:6:38
   |
LL |         .filter(|c| "aeiou".contains(c))
   |                             -------- ^ the trait `Fn<(char,)>` is not implemented for `&char`, which is required by `&char: Pattern<'_>`
   |                             |
   |                             required by a bound introduced by this call
   |
   = note: required for `&char` to implement `FnOnce<(char,)>`
   = note: required for `&char` to implement `Pattern<'_>`
note: required by a bound in `core::str::<impl str>::contains`
  --> $SRC_DIR/core/src/str/mod.rs:LL:COL
help: consider dereferencing here
   |
LL |         .filter(|c| "aeiou".contains(*c))
   |                                      +
```

Fix rust-lang#79359, fix rust-lang#119983, fix rust-lang#118779, cc rust-lang#118415 (the suggestion needs to change), cc rust-lang#121398 (doesn't fix the underlying issue).

…=jackh726

Harmonize using root or leaf obligation in trait error reporting

When rust-lang#121826 changed the error reporting to use root obligation and not the leafmost obligation, it didn't actually make sure that all the other diagnostics helper functions used the right obligation.

Specifically, when reporting similar impl candidates we are looking for impls of the root obligation, but trying to match them against the trait ref of the leaf obligation.

This does a few other miscellaneous changes. There's a lot more clean-up that could be done here, but working with this code is really grief-inducing due to how messy it has become over the years. Someone really needs to show it love. 😓

r? `@estebank`

Fixes rust-lang#126129

…=jackh726

Harmonize using root or leaf obligation in trait error reporting

When rust-lang#121826 changed the error reporting to use root obligation and not the leafmost obligation, it didn't actually make sure that all the other diagnostics helper functions used the right obligation.

Specifically, when reporting similar impl candidates we are looking for impls of the root obligation, but trying to match them against the trait ref of the leaf obligation.

This does a few other miscellaneous changes. There's a lot more clean-up that could be done here, but working with this code is really grief-inducing due to how messy it has become over the years. Someone really needs to show it love. 😓

r? `@estebank`

Fixes rust-lang#126129

…=jackh726

Harmonize using root or leaf obligation in trait error reporting

When rust-lang#121826 changed the error reporting to use root obligation and not the leafmost obligation, it didn't actually make sure that all the other diagnostics helper functions used the right obligation.

Specifically, when reporting similar impl candidates we are looking for impls of the root obligation, but trying to match them against the trait ref of the leaf obligation.

This does a few other miscellaneous changes. There's a lot more clean-up that could be done here, but working with this code is really grief-inducing due to how messy it has become over the years. Someone really needs to show it love. 😓

r? ``@estebank``

Fixes rust-lang#126129

Rollup merge of rust-lang#126142 - compiler-errors:trait-ref-split, r=jackh726

Harmonize using root or leaf obligation in trait error reporting

When rust-lang#121826 changed the error reporting to use root obligation and not the leafmost obligation, it didn't actually make sure that all the other diagnostics helper functions used the right obligation.

Specifically, when reporting similar impl candidates we are looking for impls of the root obligation, but trying to match them against the trait ref of the leaf obligation.

This does a few other miscellaneous changes. There's a lot more clean-up that could be done here, but working with this code is really grief-inducing due to how messy it has become over the years. Someone really needs to show it love. 😓

r? ``@estebank``

Fixes rust-lang#126129