resolve: Minor cleanup of duplicate macro reexports
Enabled by https://github.com/rust-lang/rust/pull/65785 which changed `duplicate_macro_exports` from a lint to a hard error.
Refactor expression parsing thoroughly
Based on https://github.com/rust-lang/rust/pull/66994 together with which this has refactored basically the entirety of `expr.rs`.
r? @estebank
Ensure that evaluating or validating a constant never reads from a static
r? @RalfJung
as per https://github.com/rust-lang/rust/pull/66302#issuecomment-554663387
This does not yet address the fact that evaluation of a constant can read from a static (under unleash-miri)
Initial implementation of `#![feature(bindings_after_at)]`
Following up on #16053, under the gate `#![feature(bindings_after_at)]`, `x @ Some(y)` is allowed subject to restrictions necessary for soundness.
The implementation and test suite should be fairly complete now.
One aspect that is not covered is the interaction with nested `#![feature(or_patterns)]`.
This is not possible to test at the moment in a good way because that feature has not progressed sufficiently and has fatal errors in MIR building. We should make sure to add such tests before we stabilize both features (but shipping one of them is fine).
r? @pnkfelix
cc @nikomatsakis @matthewjasper @pcwalton
cc https://github.com/rust-lang/rust/issues/65490
Improve diagnostics for invalid assignment
- Improve wording and span information for invalid assignment diagnostics.
- Link to https://github.com/rust-lang/rfcs/issues/372 when it appears the user is trying a destructuring assignment.
- Make the equality constraint in `where` clauses error consistent with the invalid assignment error.
This purges uses of uninitialized where possible from test cases. Some
are merely moved over to the equally bad pattern of
MaybeUninit::uninit().assume_init() but with an annotation that this is
"the best we can do".
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
Indicate origin of where type parameter for uninferred types
Based on #65951 (which is not merge yet), fixes#67277.
This PR improves a little the diagnostic for code like:
```
async fn foo() {
bar().await;
}
async fn bar<T>() -> () {}
```
by showing:
```
error[E0698]: type inside `async fn` body must be known in this context
--> unresolved_type_param.rs:9:5
|
9 | bar().await;
| ^^^ cannot infer type for type parameter `T` declared on the function `bar`
|
...
```
(The
```
declared on the function `bar`
```
part is new)
A small side note: `Vec` and `slice` seem to resist this change, because querying `item_name()` panics, and `get_opt_name()` returns `None`.
r? @estebank
Enable `loop` and `while` in constants behind a feature flag
This PR is an initial implementation of #52000. It adds a `const_loop` feature gate, which allows `while` and `loop` expressions through both HIR and MIR const-checkers if enabled. `for` expressions remain forbidden by the HIR const-checker, since they desugar to a call to `IntoIterator::into_iter`, which will be rejected anyways.
`while` loops also require [`#![feature(const_if_match)]`](https://github.com/rust-lang/rust/pull/66507), since they have a conditional built into them. The diagnostics from the HIR const checker will suggest this to the user.
r? @oli-obk
cc @rust-lang/wg-const-eval
Improve diagnostics and code for exhaustiveness of empty matches
There was a completely separate check and diagnostics for the case of an empty match. This led to slightly different error messages and duplicated code.
This improves code reuse and generally clarifies what happens for empty matches. This also clarifies the action of the `exhaustive_patterns` feature, and ensures that this feature doesn't change diagnostics in places it doesn't need to.
