Allow Abort terminators in all const-contexts
#77512
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These appear along the cleanup path inside functions with `#[unwind(aborts)]`. We don't const-check the cleanup path anyways, since const-eval already has "abort-on-panic" semantics and there's often drops that would otherwise be forbidden, so the check wasn't really preventing anything anyways.
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| TerminatorKind::GeneratorDrop | TerminatorKind::Yield { .. } => { | ||
| self.check_op(ops::Generator(hir::GeneratorKind::Gen)) | ||
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| TerminatorKind::Assert { .. } | ||
| TerminatorKind::Abort |
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Maybe add a comment here saying that Abort terminators are only used for #[unwind(aborts)] and since CTFE does not unwind, they are thus unreachable?
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I could just span_bug here actually. AFAICT, there are only Aborts in "cleanup" blocks.
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That sounds like a good idea but does not replace a comment. :)
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| #![feature(unwind_attributes, const_panic)] | ||
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| // `#[unwind(aborts)]` is okay for a `const fn`. We don't unwind in const-eval anyways. |
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Why did you add two tests? Our test suite is already huge.^^
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One is check-pass, the other fails to compile.
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I can see that, I just do not understand their respective purpose. Specifically, "consts/unwind-abort" does not even run any CTFE, and the other test already checks that the Abort terminator is accepted.
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🤷 I'm happy with the test coverage in this PR.
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I am trying to understand what unwind-abort.rs tests that the other test does not already cover.
My concern is not too little coverage; my concern is unnecessarily growing the number of UI tests.
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I try to split up passing and failing tests when possible. One is solely a test of const-checking and involves no const-eval, the other is a sanity check to ensure that the CTFE engine doesn't do anything weird when evaluating something with #[unwind(aborts)].
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I think this unnecessarily leads to an excessive number of tests in our UI test suite that is already so big that it becomes hard to run the entire thing, but whatever.
Could you add comments to these tests explaining what they are meant to test?
Co-authored-by: Ralf Jung <[email protected]>
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@bors r+ |
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📌 Commit 6ae1da3 has been approved by |
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Rollup of 11 pull requests Successful merges: - rust-lang#75853 (Use more intra-doc-links in `core::fmt`) - rust-lang#75928 (Remove trait_selection error message in specific case) - rust-lang#76329 (Add check for doc alias attribute at crate level) - rust-lang#77219 (core::global_allocator docs link to std::alloc::GlobalAlloc) - rust-lang#77395 (BTreeMap: admit the existence of leaf edges in comments) - rust-lang#77407 (Improve build-manifest to work with the improved promote-release) - rust-lang#77426 (Include scope id in SocketAddrV6::Display) - rust-lang#77439 (Fix missing diagnostic span for `impl Trait` with const generics, and add various tests for `min_const_generics` and `const_generics`) - rust-lang#77471 (BTreeMap: refactoring around edges, missed spots) - rust-lang#77512 (Allow `Abort` terminators in all const-contexts) - rust-lang#77514 (Replace some once(x).chain(once(y)) with [x, y] IntoIter) Failed merges: r? `@ghost`
We never unwind during const-eval, so we basically have these semantics already. Also I just figured out that these only appear along the cleanup path, which doesn't get const-checked. In other words, this doesn't actually change behavior: the
check-passtest I added compiles just fine on nightly.r? @RalfJung
cc @rust-lang/wg-const-eval