Don't require `allow_internal_unstable` unless `staged_api` is enabled.
#63770 changed `qualify_min_const_fn` to require `allow_internal_unstable` for *all* crates that used an unstable feature, regardless of whether `staged_api` was enabled or the `fn` that used that feature was stably const. In practice, this meant that every crate in the ecosystem that wanted to use nightly features added `#![feature(const_fn)]`, which skips `qualify_min_const_fn` entirely.
After this PR, crates that do not have `#![feature(staged_api)]` will only need to enable the feature they are interested in. For example, `#![feature(const_if_match)]` will be enough to enable `if` and `match` in constants. Crates with `staged_api` (e.g., `libstd`) require `#[allow_internal_unstable]` to be added to a function if it uses nightly features unless that function is also marked `#[rustc_const_unstable]`. This prevents proliferation of `#[allow_internal_unstable]` into functions that are not callable in a `const` context on stable.
r? @oli-obk (author of #63770)
cc @Centril
This flag opts out of the min-const-fn checks entirely, which is usually
not what we want. The few cases where the flag is still necessary have
been annotated.
This is used for both the `?const` syntax in bounds as well as the `impl
const Trait` syntax. I also considered handling these separately by
adding a variant of `TraitBoundModifier` and a field to
`ItemKind::Impl`, but this approach was less intrusive.
Add a check for swapped words when we can't find an identifier
Fixes#66968
Couple things here:
1. The matches take the precedence of case insensitive match, then levenshtein match, then swapped words match. Doing this allows us to not even check for swapped words unless the other checks return `None`.
2. I've assumed that the swapped words check is not held to the limits of the max levenshtein distance threshold (ie. we want to try and find a match even if the levenshtein distance is very high). This means that we cannot perform this check in the `fold` that occurs after the `filter_map` call, because the candidate will be filtered out. So, I've split this into two separate `fold` calls, and had to collect the original iterator into a vec so it can be copied (I don't think we want to change the function signature to take a vec or require the `Copy` trait). An alternative implemenation may be to remove the `filter_map`, `fold` over the entire iterator, and do a check against `max_dist` inside the relevant cases there.
r? @estebank
Require issue = "none" over issue = "0" in unstable attributes
These changes make the use of `issue = "none"` required in unstable attributes throughout the compiler.
Notes:
- #66299 is now in beta so `issue = "none"` is accepted.
- The `tidy` tool now fails on `issue = "0"`.
- Tests that used `issue = "0"` were changed to use `issue = "none"`, except for _one_ that asserts `issue = "0"` can still be used.
- The compiler still allows `issue = "0"` because some submodules require it, this could be disallowed once these are updated.
Resolves#41260
r? @varkor
Merge `TraitItem` & `ImplItem into `AssocItem`
In this PR we:
- Merge `{Trait,Impl}Item{Kind?}` into `AssocItem{Kind?}` as discussed in https://github.com/rust-lang/rust/issues/65041#issuecomment-538105286.
- This is done by using the cover grammar of both forms.
- In particular, it requires that we syntactically allow (under `#[cfg(FALSE)]`):
- `default`ness on `trait` items,
- `impl` items without a body / definition (`const`, `type`, and `fn`),
- and associated `type`s in `impl`s with bounds, e.g., `type Foo: Ord;`.
- The syntactic restrictions are replaced by semantic ones in `ast_validation`.
- Move syntactic restrictions around C-variadic parameters from the parser into `ast_validation`:
- `fn`s in all contexts now syntactically allow `...`,
- `...` can occur anywhere in the list syntactically (`fn foo(..., x: usize) {}`),
- and `...` can be the sole parameter (`fn foo(...) {}`.
r? @petrochenkov
Add a raw "address of" operator
* Parse and feature gate `&raw [const | mut] expr` (feature gate name is `raw_address_of`)
* Add `mir::Rvalue::AddressOf`
* Use the new `Rvalue` for:
* the new syntax
* reference to pointer casts
* drop shims for slices and arrays
* Stop using `mir::Rvalue::Cast` with a reference as the operand
* Correctly evaluate `mir::Rvalue::{Ref, AddressOf}` in constant propagation
cc @Centril @RalfJung @oli-obk @eddyb
cc #64490
