Rollup of 7 pull requests
Successful merges:
- #110038 (Erase regions when confirming transmutability candidate)
- #110341 (rustdoc: stop passing a title to `replaceState` second argument)
- #110388 (Add a message for if an overflow occurs in `core::intrinsics::is_nonoverlapping`.)
- #110404 (fix clippy::toplevel_ref_arg and ::manual_map)
- #110421 (Spelling librustdoc)
- #110423 (Spelling srcdoc)
- #110433 (Windows: map a few more error codes to ErrorKind)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Alloc `hir::Lit` in an arena to remove the destructor from `Expr`
This allows allocating `Expr`s into a dropless arena, which is useful for using length prefixed thing slices in HIR, since these can only be allocated in the dropless arena and not in a typed arena.
Permit MIR inlining without #[inline]
I noticed that there are at least a handful of portable-simd functions that have no `#[inline]` but compile to an assign + return.
I locally benchmarked inlining thresholds between 0 and 50 in increments of 5, and 50 seems to be the best. Interesting. That didn't include check builds though, ~maybe perf will have something to say about that~.
Perf has little useful to say about this. We generally regress all the check builds, as best as I can tell, due to a number of small codegen changes in a particular hot function in the compiler. Probably this is because we've nudged the inlining outcomes all over, and uses of `#[inline(always)]`/`#[inline(never)]` might need to be adjusted.
This allows allocating `Expr`s into a dropless arena, which is useful
for using length prefixed thing slices in HIR, since these can only be
allocated in the dropless arena and not in a typed arena. This is
something I'm working on.
Remove the loop in `Align::from_bytes`
Perf is almost certainly irrelevant, but might as well simplify it, since `trailing_zeros` does exactly what's needed.
Remove `TypeSuper{Foldable,Visitable}` impls for `Region`.
These traits exist so that folders/visitors can recurse into types of interest: binders, types, regions, predicates, and consts. But `Region` is non-recursive and cannot contain other types of interest, so its methods in these traits are trivial.
This commit inlines and removes those trivial methods.
r? `@compiler-errors`
Remove `remap_env_constness` in queries
This removes some of the complexities with const traits. #88119 used to be caused by this but was fixed by `param_env = param_env.without_const()`.
This allows us to get rid of the `rustc_const_eval->rustc_borrowck`
dependency edge which was delaying the compilation of borrowck.
The added utils in `rustc_middle` are small and should not affect
compile times there.
Don't `use rustc_hir as ast`(!)
It makes for confusing code.
This was introduced in a large commit in #67886 that rearranged a lot of `use` statements. I suspect it was an accident.
suggest lifetime for closure parameter type when mismatch
This is a draft PR, will add test cases later and be ready for review.
This PR fixes https://github.com/rust-lang/rust/issues/105675 by adding a diagnostics suggestion. Also a partial fix to https://github.com/rust-lang/rust/issues/105528.
The following code will have a compile error now:
```
fn const_if_unit(input: bool) -> impl for<'a> FnOnce(&'a ()) -> usize {
let x = |_| 1;
x
}
```
Before this PR:
```
error[E0308]: mismatched types
--> src/lib.rs:3:5
|
3 | x
| ^ one type is more general than the other
|
= note: expected trait `for<'a> FnOnce<(&'a (),)>`
found trait `FnOnce<(&(),)>`
note: this closure does not fulfill the lifetime requirements
--> src/lib.rs:2:13
|
2 | let x = |_| 1;
| ^^^
error: implementation of `FnOnce` is not general enough
--> src/lib.rs:3:5
|
3 | x
| ^ implementation of `FnOnce` is not general enough
|
= note: closure with signature `fn(&'2 ()) -> usize` must implement `FnOnce<(&'1 (),)>`, for any lifetime `'1`...
= note: ...but it actually implements `FnOnce<(&'2 (),)>`, for some specific lifetime `'2`
For more information about this error, try `rustc --explain E0308`.
error: could not compile `rust-test` due to 2 previous errors
```
After this PR:
```
error[E0308]: mismatched types
--> src/lib.rs:3:5
|
3 | x
| ^ one type is more general than the other
|
= note: expected trait `for<'a> FnOnce<(&'a (),)>`
found trait `FnOnce<(&(),)>`
note: this closure does not fulfill the lifetime requirements
--> src/lib.rs:2:13
|
2 | let x = |_| 1;
| ^^^
help: consider changing the type of the closure parameters
|
2 | let x = |_: &_| 1;
| ~~~~~~~
error: implementation of `FnOnce` is not general enough
--> src/lib.rs:3:5
|
3 | x
| ^ implementation of `FnOnce` is not general enough
|
= note: closure with signature `fn(&'2 ()) -> usize` must implement `FnOnce<(&'1 (),)>`, for any lifetime `'1`...
= note: ...but it actually implements `FnOnce<(&'2 (),)>`, for some specific lifetime `'2`
For more information about this error, try `rustc --explain E0308`.
error: could not compile `rust-test` due to 2 previous errors
```
After applying the suggestion, it compiles. The suggestion might not always be correct as the generation procedure of that suggestion is quite simple...
These traits exist so that folders/visitors can recurse into types of
interest: binders, types, regions, predicates, and consts. But `Region`
is non-recursive and cannot contain other types of interest, so its
methods in these traits are trivial.
This commit inlines and removes those trivial methods.
explicit `adt_dtorck_constraint` for `ManuallyDrop`
the only reason we didn't add outlives requirements when dropping `ManuallyDrop` was a fast-path in `trivial_dropck_outlives`. Explicitly acknowledge that fast-path in `adt_dtorck_constraint`
Do not attempt to commute comparison and cast to codegen discriminants
The general algorithm to compute a discriminant is:
```
relative_tag = tag - niche_start
is_niche = relative_tag <= (ule) relative_max
discr = if is_niche {
cast(relative_tag) + niche_variants.start()
} else {
untagged_variant
}
```
We have an optimization branch which attempts to merge the addition and the subtraction by commuting them with the cast. We currently get this optimization wrong.
This PR takes the easiest and safest way: remove the optimization, and let LLVM handle it. (Perf may not agree with that course of action 😅)
There may be a less invasive solution, but I don't have the necessary knowledge of LLVM semantics to find it. Cranelift has the same optimization, which should be handled similarly.
cc `@nikic` and `@bjorn3` if you have a better solution.
Fixes https://github.com/rust-lang/rust/issues/110128
Reformulate `point_at_expr_source_of_inferred_type` to be more accurate
Be more accurate when deducing where along the several usages of a binding it is constrained to be some type that is incompatible with an expectation.
This also renames the method to `note_source_of_type_mismatch_constraint` because I prefer that name, though I guess I can revert that. (Also drive-by rename `note_result_coercion` -> `suggest_coercing_result_via_try_operator`, because it's suggesting, not noting!)
This PR is (probably?) best reviewed per commit, but it does regress a bit only to fix it later on, so it could also be reviewed as a whole if that makes the final results more clear.
r? `@estebank`
Add a stable MIR way to get the main function
This is useful for analysis tools that only analyze the code paths that a specific program actually goes through. Or for code generators built on top of stable MIR.
