Closures always implement FnOnce in new solver#109739
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bors merged 1 commit intorust-lang:masterfrom Mar 31, 2023
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Some changes occurred to the core trait solver cc @rust-lang/initiative-trait-system-refactor |
lcnr
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| Some(closure_kind) => { | |
| // If the closure's kind doesn't extend the goal kind, | |
| // then the closure doesn't implement the trait. | |
| if !closure_kind.extends(goal_kind) { | |
| return Err(NoSolution); | |
| } | |
| } | |
| // Closure kind is not yet determined | |
| None => { | |
| // All closures implement `FnOnce` | |
| if goal_kind != ty::ClosureKind::FnOnce { | |
| // Otherwise, if we don't know the `ClosureKind`, ambiguity. | |
| return Ok(None); | |
| } | |
| } | |
| // If the closure's kind doesn't extend the goal kind, | |
| // then the closure doesn't implement the trait. | |
| Some(closure_kind) => { | |
| if !closure_kind.extends(goal_kind) { | |
| return Err(NoSolution); | |
| } | |
| } | |
| // Closure kind is not yet determined, so we return ambiguity unless | |
| // the expected kind is `FnOnce` as that is always implemented. | |
| None => { | |
| if goal_kind != ty::ClosureKind::FnOnce { | |
| return Ok(None); | |
| } | |
| } |
style nit: having these kinds of nested comments imo makes the code more verbose and harder to read. Can't explain it well but I guess part of the issue is that I have to switch between reading the comment, and reading the actual source.
r=me with or without this nit applied
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r? @lcnr 😁 |
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@bors r=lcnr rollup (new solver) |
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Dylan-DPC
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…-fnonce, r=lcnr Closures always implement `FnOnce` in new solver We should process `[closure]: FnOnce(Tys...) -> Ty` obligations *before* fallback and closure analysis. We can do this by taking advantage of the fact that `FnOnce` is always implemented by closures, even before we definitely know the closure kind. Fixes compiler-errors/next-solver-hir-issues#15 r? `@oli-obk` (trying to spread the reviewer load for new trait solver prs, and this one is pretty self-contained, though feel free to reassign 😸)
bors
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…mpiler-errors Rollup of 6 pull requests Successful merges: - rust-lang#109347 (Skip no_mangle if the item has no name.) - rust-lang#109522 (Implement current_dll_path for AIX) - rust-lang#109679 (Freshen normalizes-to hack goal RHS in the evaluate loop) - rust-lang#109704 (resolve: Minor improvements to effective visibilities) - rust-lang#109739 (Closures always implement `FnOnce` in new solver) - rust-lang#109758 (Parallel compiler cleanups) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
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We should process
[closure]: FnOnce(Tys...) -> Tyobligations before fallback and closure analysis. We can do this by taking advantage of the fact thatFnOnceis always implemented by closures, even before we definitely know the closure kind.Fixes compiler-errors/next-solver-hir-issues#15
r? @oli-obk (trying to spread the reviewer load for new trait solver prs, and this one is pretty self-contained, though feel free to reassign 😸)