Now that rust-lang#90435 seems to have been resolved.

With rust-lang/miri#3739 merged, the deduplication hack is no longer necessary.

…defining scope

…efining scope

We are moving toward forbidding `missing_fragment_specifier` either in
edition 2024 or unconditionally. Make a first step toward this by
ensuring crates that rely on the old behavior are reported when used as
dependencies.

Tracking issue: <rust-lang#128143>

…hecks, r=lcnr

Do not try to reveal hidden types when trying to prove auto-traits in the defining scope

fixes rust-lang#99793

this avoids the cycle error by just causing a selection error, which is not fatal. We pessimistically assume that freeze does not hold, which is always a safe assumption.

Implement `unsigned_signed_diff`

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Implements rust-lang#126041

Improved clarity of documentation for std::fs::create_dir_all

Closes rust-lang#88264

…mpiler-errors

Fix malformed suggestion for repeated maybe unsized bounds

Fixes rust-lang#127441

Now when we encounter something like `foo(a : impl ?Sized + ?Sized)`, instead of suggesting removal of both bounds and leaving `foo(a: impl )` behind, we suggest changing the first bound to `Sized` and removing the second bound, resulting in `foo(a: impl Sized)`.

Although the issue was reported for impl trait types, it also occurred with regular param bounds. So if we encounter `foo<T: ?Sized + ?Sized>(a: T)` we now detect that all the bounds are `?Sized` and therefore emit the suggestion to remove the entire predicate `: ?Sized + ?Sized` resulting in `foo<T>(a: T)`.

Lastly, if we encounter a situation where some of the bounds are something other than `?Sized`, then we emit separate removal suggestions for each `?Sized` bound. E.g. if we see `foo(a: impl ?Sized + Bar + ?Sized)` or `foo<T: ?Sized + Bar + ?Sized>(a: T)` we emit suggestions such that the user will be left with `foo(a : impl Bar)` or `foo<T: Bar>(a: T)` respectively.

Fix some `#[cfg_attr(not(doc), repr(..))]`

Now that rust-lang#90435 seems to have been resolved.

…r-unconditional, r=petrochenkov

Mark `missing_fragment_specifier` as `FutureReleaseErrorReportInDeps`

We are moving toward forbidding `missing_fragment_specifier` either in edition 2024 or unconditionally. Make a first step toward this by ensuring crates that rely on the old behavior are reported when used as dependencies.

Tracking issue: <rust-lang#128143>

std: use duplicate thread local state in tests

With rust-lang/miri#3739 merged, the deduplication hack is no longer necessary.

…r-conversions, r=compiler-errors

Remove Unnecessary `.as_str()` Conversions

Because comparing interned values is much more efficient than converting a `rustc_span::symbol::Ident` to `&str`  and then doing the comparison.

docs: https://doc.rust-lang.org/stable/nightly-rustc/rustc_span/symbol/struct.Ident.html#method.as_str