Report precondition violation for <usize as SliceIndex>::get_unchecked in const-eval - #161616
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<usize as SliceIndex>::get_unchecked in const-eval<usize as SliceIndex>::get_unchecked in const-eval
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Any special-casing of Miri in the standard library requires review. cc @rust-lang/miri |
RalfJung
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@bors squash |
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…ed` in const-eval * Add a test for the diagnostics on `<usize as SliceIndex>::get_unchecked` in const-eval * Report a precondition violation for `<usize as SliceIndex>::get_unchecked` in const-eval The precondition check was gated on `check_language_ub`, which is disabled in const-eval and Miri, on the grounds that the `assume` below it is language UB that the interpreter will catch anyway. It does catch it, but only as "`assume` called with `false`", which says nothing about what the caller did wrong. This commit instead gates the check on `check_library_ub`, matching `get_unchecked_mut`, so that the interpreter reports the violated precondition. * fixup! Report a precondition violation for `<usize as SliceIndex>::get_unchecked` in const-eval * tweak comment Co-authored-by: Ralf Jung <post@ralfj.de>
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Makes sense, thanks :) |
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…precondition-const-eval, r=RalfJung Report precondition violation for `<usize as SliceIndex>::get_unchecked` in const-eval The precondition check was gated on `check_language_ub`, which is disabled in const-eval and Miri, on the grounds that the `assume` below it is language UB that the interpreter will catch anyway. It does catch it, but only as "`assume` called with `false`", which says nothing about what the caller did wrong. This PR instead gates the check on `check_library_ub`, matching `get_unchecked_mut`, so that the interpreter reports the violated precondition. Fixes rust-lang#161611
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The precondition check was gated on
check_language_ub, which is disabled in const-eval and Miri, on the grounds that theassumebelow it is language UB that the interpreter will catch anyway. It does catch it, but only as "assumecalled withfalse", which says nothing about what the caller did wrong.This PR instead gates the check on
check_library_ub, matchingget_unchecked_mut, so that the interpreter reports the violated precondition.Fixes #161611
@rustbot label +A-const-eval +A-diagnostics +A-slice +T-libs +requires-nightly