Do not use `ParamEnv::and` when building a cache key from a param-env and trait eval candidate
Do not use `ParamEnv::and` to cache a param-env with a selection/evaluation candidate.
This is because if the param-env is `RevealAll` mode, and the candidate looks global (i.e. it has erased regions, which can show up when we normalize a projection type under a binder<sup>1</sup>), then when we use `ParamEnv::and` to pair the candidate and the param-env for use as a cache key, we will throw away the param-env's caller bounds, and we'll end up caching a candidate that we inferred from the param-env with a empty param-env, which may cause cache-hit later when we have an empty param-env, and possibly mess with normalization like we see in the referenced issue during codegen.
Not sure how to trigger this with a more structured test, but changing `check-pass` to `build-pass` triggers the case that https://github.com/rust-lang/rust/issues/94903 detected.
<sup>1.</sup> That is, we will replace the late-bound region with a placeholder, which gets canonicalized and turned into an infererence variable, which gets erased during region freshening right before we cache the result. Sorry, it's quite a few steps.
Fixes#94903
r? `@Aaron1011` (or reassign as you see fit)
interpret: make isize::MAX the limit for dynamic value sizes
We are currently enforcing `data_layout.obj_size_bound()` as the maximal dynamic size of a Rust value (including for `size_of_val_raw`), but that does not match the docs.
In particular, Miri currently falsely says that this code has UB:
```rust
#![feature(layout_for_ptr)]
fn main() {
let size = isize::MAX as usize;
// Creating a raw slice of size isize::MAX and asking for its size is okay.
let s = std::ptr::slice_from_raw_parts(1usize as *const u8, size);
assert_eq!(size, unsafe { std::mem::size_of_val_raw(s) });
}
```
Better suggestions for `Fn`-family trait selection errors
1. Suppress suggestions to add `std::ops::Fn{,Mut,Once}` bounds when a type already implements `Fn{,Mut,Once}`
2. Add a note that points out that a type does in fact implement `Fn{,Mut,Once}`, but the arguments vary (either by number or by actual arguments)
3. Add a note that points out that a type does in fact implement `Fn{,Mut,Once}`, but not the right one (e.g. implements `FnMut`, but `Fn` is required).
Fixes#95147
A more robust solution to finding where to place use suggestions was added.
The algorithm uses the AST to find the span for the suggestion so we pass this span
down to the HIR during lowering and use it.
Signed-off-by: Miguel Guarniz <mi9uel9@gmail.com>
Spellchecking compiler comments
This PR cleans up the rest of the spelling mistakes in the compiler comments. This PR does not change any literal or code spelling issues.
Restore `impl Future<Output = Type>` to async blocks
I was sad when I undid some of the code I wrote in #91096 in the PR #95225, so I fixed it here to not print `[async output]`.
This PR "manually" normalizes the associated type `<[generator] as Generator>::Return` type which appears very frequently in `impl Future` types that result from async block desugaring.
Rollup of 6 pull requests
Successful merges:
- #93901 (Stabilize native library modifier syntax and the `whole-archive` modifier specifically)
- #94806 (Fix `cargo run tidy`)
- #94869 (Add the generic_associated_types_extended feature)
- #95011 (async: Give predictable name to binding generated from .await expressions.)
- #95251 (Reduce max hash in raw strings from u16 to u8)
- #95298 (Fix double drop of allocator in IntoIter impl of Vec)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Add the generic_associated_types_extended feature
Right now, this only ignore obligations that reference new placeholders in `poly_project_and_unify_type`. In the future, this might do other things, like allowing object-safe GATs.
**This feature is *incomplete* and quite likely unsound. This is mostly just for testing out potential future APIs using a "relaxed" set of rules until we figure out *proper* rules.**
Also drive by cleanup of adding a `ProjectAndUnifyResult` enum instead of using a `Result<Result<Option>>`.
r? `@nikomatsakis`
Remember mutability in `DefKind::Static`.
This allows to compute the `BodyOwnerKind` from `DefKind` only, and
removes a direct dependency of some MIR queries onto HIR.
As a side effect, it also simplifies metadata, since we don't need 4
flavours of `EntryKind::*Static` any more.
allow arbitrary inherent impls for builtin types in core
Part of https://github.com/rust-lang/compiler-team/issues/487. Slightly adjusted after some talks with `@m-ou-se` about the requirements of `t-libs-api`.
This adds a crate attribute `#![rustc_coherence_is_core]` which allows arbitrary impls for builtin types in core.
For other library crates impls for builtin types should be avoided if possible. We do have to allow the existing stable impls however. To prevent us from accidentally adding more of these in the future, there is a second attribute `#[rustc_allow_incoherent_impl]` which has to be added to **all impl items**. This only supports impls for builtin types but can easily be extended to additional types in a future PR.
This implementation does not check for overlaps in these impls. Perfectly checking that requires us to check the coherence of these incoherent impls in every crate, as two distinct dependencies may add overlapping methods. It should be easy enough to detect if it goes wrong and the attribute is only intended for use inside of std.
The first two commits are mostly unrelated cleanups.
Rollup of 5 pull requests
Successful merges:
- #95294 (Document Linux kernel handoff in std::io::copy and std::fs::copy)
- #95443 (Clarify how `src/tools/x` searches for python)
- #95452 (fix since field version for termination stabilization)
- #95460 (Spellchecking compiler code)
- #95461 (Spellchecking some comments)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
This allows to compute the `BodyOwnerKind` from `DefKind` only, and
removes a direct dependency of some MIR queries onto HIR.
As a side effect, it also simplifies metadata, since we don't need 4
flavours of `EntryKind::*Static` any more.
