Allocate HIR on an arena 4/4
This is the fourth and last PR in the series started by #66931, #66936 and #66942.
The last commits should compile on their own.
The difference with the previous PR is given by https://github.com/cjgillot/rust/compare/hirene-ty...hirene
A few more cleanups may be necessary, please tell me.
r? @eddyb like the other
cc @Zoxc
typeck: note other end-point when checking range pats
Fixes#57389, alternative to #67214 that should be less invasive to type checking logic.
r? @estebank
When encountering `_` type placeholder in fn arguments and return type,
suggest using generic type parameters.
Expand what counts as an inferable return type to slice, array and
tuples of `_`.
This still doesn't handle the case entirely correctly, requiring a more
targeted approach with a better suggestion, but at least now the
suggested syntax makes *some* sense.
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.
