mirror of
https://github.com/rust-lang/rust.git
synced 2025-05-09 16:37:36 +00:00
c2a408840a
Introduce `let...else` Tracking issue: #87335 The trickiest part for me was enforcing the diverging else block with clear diagnostics. Perhaps the obvious solution is to expand to `let _: ! = ..`, but I decided against this because, when a "mismatched type" error is found in typeck, there is no way to trace where in the HIR the expected type originated, AFAICT. In order to pass down this information, I believe we should introduce `Expectation::LetElseNever(HirId)` or maybe add `HirId` to `Expectation::HasType`, but I left that as a future enhancement. For now, I simply assert that the block is `!` with a custom `ObligationCauseCode`, and I think this is clear enough, at least to start. The downside here is that the error points at the entire block rather than the specific expression with the wrong type. I left a todo to this effect. Overall, I believe this PR is feature-complete with regard to the RFC. |
||
|---|---|---|
| .. | ||
| dep_graph | ||
| hir | ||
| ich | ||
| infer | ||
| middle | ||
| mir | ||
| query | ||
| traits | ||
| ty | ||
| util | ||
| arena.rs | ||
| lib.rs | ||
| lint.rs | ||
| macros.rs | ||
| tests.rs | ||
| thir.rs | ||