Instead of

```
error[E0308]: mismatched types
 --> tests/ui/suggestions/only-suggest-removal-of-conversion-method-calls.rs:9:5
  |
4 | fn get_name() -> String {
  |                  ------ expected `String` because of return type
...
9 |     your_name.trim() //~ ERROR E0308
  |     ^^^^^^^^^^^^^^^^ expected `String`, found `&str`
  |
help: try removing the method call
  |
9 -     your_name.trim()
9 +     your_name
```

output

```
error[E0308]: mismatched types
  --> $DIR/only-suggest-removal-of-conversion-method-calls.rs:9:5
   |
LL | fn get_name() -> String {
   |                  ------ expected `String` because of return type
...
LL |     your_name.trim()
   |     ^^^^^^^^^^^^^^^^- help: try using a conversion method: `.to_string()`
   |     |
   |     expected `String`, found `&str`
```

Fix rust-lang#114329.

…assoc types

```
error[E0277]: the size for values of type `[i32]` cannot be known at compilation time
   --> f100.rs:2:33
    |
2   |     let _ = std::mem::size_of::<[i32]>();
    |                                 ^^^^^ doesn't have a size known at compile-time
    |
    = help: the trait `Sized` is not implemented for `[i32]`
note: required by an implicit `Sized` bound in `std::mem::size_of`
   --> /home/gh-estebank/rust/library/core/src/mem/mod.rs:312:22
    |
312 | pub const fn size_of<T>() -> usize {
    |                      ^ required by the implicit `Sized` requirement on this bound in `size_of`
```

Fix rust-lang#120178.

Given the previous change to add implicit `Sized` bounds only if there
isn't already an explicit `Sized` bound, now the incr comp machinery
doesn't consider adding the explicit bound as being dirty, as long as
`-Zincremental-ignore-spans` is set.

This is noted as an implementation concern under the tracking issue for `?` and `try` blocks. (Issue 31436)

Add FileCheck annotations to dataflow-const-prop tests

part of rust-lang#116971.

A few shadowing variable names are changed, so that it is easier to match the variable names in MIR using FileCheck syntax.

Also, there's a FIXME in [enum.rs](https://github.com/rust-lang/rust/pull/119759/files#diff-7621f55327838e489a95ac99ae1e6126b37c57aff582594e6bee9d7e7e56fc58) because the MIR looks suspicious to me. It has been explained in the comments.

r? cjgillot

On E0277 be clearer about implicit `Sized` bounds on type params and assoc types

```
error[E0277]: the size for values of type `[i32]` cannot be known at compilation time
   --> f100.rs:2:33
    |
2   |     let _ = std::mem::size_of::<[i32]>();
    |                                 ^^^^^ doesn't have a size known at compile-time
    |
    = help: the trait `Sized` is not implemented for `[i32]`
note: required by an implicit `Sized` bound in `std::mem::size_of`
   --> /home/gh-estebank/rust/library/core/src/mem/mod.rs:312:22
    |
312 | pub const fn size_of<T>() -> usize {
    |                      ^ required by the implicit `Sized` requirement on this bound in `size_of`
```

Fix rust-lang#120178.

Only suggest removal of `as_*` and `to_` conversion methods on E0308

Instead of

```
error[E0308]: mismatched types
 --> tests/ui/suggestions/only-suggest-removal-of-conversion-method-calls.rs:9:5
  |
4 | fn get_name() -> String {
  |                  ------ expected `String` because of return type
...
9 |     your_name.trim()
  |     ^^^^^^^^^^^^^^^^ expected `String`, found `&str`
  |
help: try removing the method call
  |
9 -     your_name.trim()
9 +     your_name
```

output

```
error[E0308]: mismatched types
  --> $DIR/only-suggest-removal-of-conversion-method-calls.rs:9:5
   |
LL | fn get_name() -> String {
   |                  ------ expected `String` because of return type
...
LL |     your_name.trim()
   |     ^^^^^^^^^^^^^^^^- help: try using a conversion method: `.to_string()`
   |     |
   |     expected `String`, found `&str`
```

Fix rust-lang#114329.

…h-arm, r=compiler-errors

add test for try-block-in-match-arm

This is noted as an implementation concern under the tracking issue for `?` and `try` blocks. (Issue 31436)

Refs: rust-lang#31436

…t-pat, r=compiler-errors

`#![feature(inline_const_pat)]` is no longer incomplete

Now that borrow checking and safety checking is implemented for inline constant patterns, the incomplete feature status is not necessary. Stabilizing this feature requires more testing and has some of the same unresolved questions as inline constants.

cc rust-lang#76001

…gate, r=compiler-errors

Correctly check `never_type` feature gating

Fixes rust-lang#120542.

The feature wasn't tested on return type of a generic function type, so it got under the radar in rust-lang#120316.

r? ```@compiler-errors```

…ew-queue, r=Mark-Simulacrum

put pnkfelix (me) back on the review queue.

I have more bandwidth and want to take on more review load.

…m-diags, r=oli-obk

Improve the diagnostics for unused generic parameters

* Don't emit two errors (namely E0091 *and* E0392) for unused type parameters on *lazy* type aliases
* Fix the diagnostic help message of E0392 for *lazy* type aliases: Don't talk about the “fields” of lazy type aliases (use the term “body” instead) and don't suggest `PhantomData` for them, it doesn't make much sense
* Consolidate the diagnostics for E0091 (unused type parameters in type aliases) and E0392 (unused generic parameters due to bivariance) and make it translatable
  * Still keep the error codes distinct (for now)
  * Naturally leads to better diagnostics for E0091

r? ```@oli-obk``` (to ballast your review load :P) or compiler