Rollup of 9 pull requests
Successful merges:
- #92390 (Constify a few `(Partial)Ord` impls)
- #97077 (Simplify some code that depend on Deref)
- #98710 (correct the output of a `capacity` method example)
- #99084 (clarify how write_bytes can lead to UB due to invalid values)
- #99178 (Lighten up const_prop_lint, reusing const_prop)
- #99673 (don't ICE on invalid dyn calls)
- #99703 (Expose size_hint() for TokenStream's iterator)
- #99709 (`Inherited` always has `TypeckResults` available)
- #99713 (Fix sidebar background)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Expose size_hint() for TokenStream's iterator
The iterator for `proc_macro::TokenStream` is a wrapper around a `Vec` iterator:
babff2211e/library/proc_macro/src/lib.rs (L363-L371)
so it can cheaply provide a perfectly precise size hint, with just a pointer subtraction:
babff2211e/library/alloc/src/vec/into_iter.rs (L170-L177)
I need the size hint in syn (https://github.com/dtolnay/syn/blob/1.0.98/src/buffer.rs) to reduce allocations when converting TokenStream into syn's internal TokenBuffer representation.
Aside from `size_hint`, the other non-default methods in `std::vec::IntoIter`'s `Iterator` impl are `advance_by`, `count`, and `__iterator_get_unchecked`. I've included `count` in this PR since it is trivial. I did not include `__iterator_get_unchecked` because it is spoopy and I did not feel like dealing with that. Lastly, I did not include `advance_by` because that requires `feature(iter_advance_by)` (https://github.com/rust-lang/rust/issues/77404) and I noticed this comment at the top of libproc_macro:
babff2211e/library/proc_macro/src/lib.rs (L20-L22)
correct the output of a `capacity` method example
The output of this example in std::alloc is different from which shown in the comment. I have tested it on both Linux and Windows.
Simplify some code that depend on Deref
Now that we can assume #97025 works, it's safe to expect Deref is always in the first place of projections. With this, I was able to simplify some code that depended on Deref's place in projections. When we are able to move Derefer before `ElaborateDrops` successfully we will be able to optimize more places.
r? `@oli-obk`
Constify a few `(Partial)Ord` impls
Only a few `impl`s are constified for now, as #92257 has not landed in the bootstrap compiler yet and quite a few impls would need that fix.
This unblocks #92228, which unblocks marking iterator methods as `default_method_body_is_const`.
Resolve function lifetime elision on the AST
~Based on https://github.com/rust-lang/rust/pull/97720~
Lifetime elision for functions is purely syntactic in nature, so can be resolved on the AST.
This PR replicates the elision logic and diagnostics on the AST, and replaces HIR-based resolution by a `delay_span_bug`.
This refactor allows for more consistent diagnostics, which don't have to guess the original code from HIR.
r? `@petrochenkov`
Resolve function lifetime elision on the AST
~Based on https://github.com/rust-lang/rust/pull/97720~
Lifetime elision for functions is purely syntactic in nature, so can be resolved on the AST.
This PR replicates the elision logic and diagnostics on the AST, and replaces HIR-based resolution by a `delay_span_bug`.
This refactor allows for more consistent diagnostics, which don't have to guess the original code from HIR.
r? `@petrochenkov`
