Remove hack for top-level or-patterns in match checking #66967
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The exact same logic was used in check_arms and check_match to build the matrix of relevant patterns. It would actually probably have been a bug if it was not the case, since exhaustiveness checking should be the same as checking reachability of an additional `_ => ...` match branch.
We want the lifetimes of the patterns contained in the matrix and the candidate `PatStack` to be the same so that they can be mixed together. A lot of this would not be necessary if `SmallVec` was covariant in its type argument (see servo/rust-smallvec#146).
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The implementation looks good. Some of the pre-existing comments could do with a drive-by clean up (capitalisation, etc.), though I'm not too bothered. Let's just make sure this doesn't regress anything. @bors try @rust-timer queue |
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Awaiting bors try build completion |
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⌛ Trying commit 1c1bec2 with merge 057e49b53cffec15c0a8467b83fe961b5f476e83... |
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☀️ Try build successful - checks-azure |
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Queued 057e49b53cffec15c0a8467b83fe961b5f476e83 with parent 2da942f, future comparison URL. |
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Finished benchmarking try commit 057e49b53cffec15c0a8467b83fe961b5f476e83, comparison URL. |
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@bors r+ |
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📌 Commit 1c1bec2 has been approved by |
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@Nadrieril This looks great! Thanks a bunch for all the work you've been doing on match checking! |
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I have to say I'm having a lot of fun doing it :D. And you all are really reactive and supportive too, thanks ! |
Remove hack for top-level or-patterns in match checking Follow-up to rust-lang#66612. Or-patterns are now truly first-class in match checking. As a side-effect, redundant subpatterns are linted as such, making the `unreachable_patterns` lint a bit more general. cc rust-lang#54883 r? @varkor
Remove hack for top-level or-patterns in match checking Follow-up to rust-lang#66612. Or-patterns are now truly first-class in match checking. As a side-effect, redundant subpatterns are linted as such, making the `unreachable_patterns` lint a bit more general. cc rust-lang#54883 r? @varkor
Rollup of 6 pull requests Successful merges: - #66148 (Show the sign for signed ops on `exact_div`) - #66651 (Add `enclosing scope` parameter to `rustc_on_unimplemented`) - #66904 (Adding docs for keyword match, move) - #66935 (syntax: Unify macro and attribute arguments in AST) - #66941 (Remove `ord` lang item) - #66967 (Remove hack for top-level or-patterns in match checking) Failed merges: r? @ghost
Follow-up to #66612.
Or-patterns are now truly first-class in match checking. As a side-effect, redundant subpatterns are linted as such, making the
unreachable_patternslint a bit more general.cc #54883
r? @varkor