Fix overlap detection of usize
/isize
range patterns
#79523
Merged
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usize
andisize
are a bit of a special case in the match usefulness algorithm, because the range of values they contain depends on the platform. Specifically, we don't want0..usize::MAX
to count as an exhaustive match (see alsoprecise_pointer_size_matching
). The way this was initially implemented is by treating those ranges like float ranges, i.e. with limited cleverness. This means we didn't catch the following as unreachable:This PRs fixes this oversight. Now the only difference between
usize
andu64
range patterns is in what ranges count as exhaustive.r? @varkor
@rustbot label +A-exhaustiveness-checking