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Add assertion to constructor_intersects_pattern

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This commit is contained in:
varkor 2018-08-20 23:59:46 +01:00
parent 6e8a625674
commit c421af995b
1 changed files with 14 additions and 10 deletions
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24
src/librustc_mir/hair/pattern/_match.rs
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@ -1517,7 +1517,14 @@ fn constructor_intersects_pattern<'p, 'a: 'p, 'tcx: 'a>(
) -> Option<Vec<&'p Pattern<'tcx>>> {
if should_treat_range_exhaustively(tcx, ctor) {
match (IntRange::from_ctor(tcx, ctor), IntRange::from_pat(tcx, pat)) {
(Some(ctor), Some(pat)) => ctor.intersection(&pat).map(|_| vec![]),
(Some(ctor), Some(pat)) => {
ctor.intersection(&pat).map(|_| {
let (pat_lo, pat_hi) = pat.range.into_inner();
let (ctor_lo, ctor_hi) = ctor.range.into_inner();
assert!(pat_lo <= ctor_lo && ctor_hi <= pat_hi);
Some(vec![])
})
}
_ => None,
}
} else {
@ -1656,21 +1663,18 @@ fn specialize<'p, 'a: 'p, 'tcx: 'a>(
}
}
_ => {
// If the constructor is a single value, we add a row to the specialised matrix
// if the pattern is equal to the constructor. If the constructor is a range of
// values, we add a row to the specialised matrix if the pattern is contained
// within the constructor. These two cases (for a single value pattern) can be
// treated as intersection.
// If the constructor is a:
// Single value: add a row if the constructor equals the pattern.
// Range: add a row if the constructor contains the pattern.
constructor_intersects_pattern(cx.tcx, constructor, pat)
}
}
}
PatternKind::Range { .. } => {
// If the constructor is a single value, we add a row to the specialised matrix if the
// pattern contains the constructor. If the constructor is a range of values, we add a
// row to the specialised matrix if there exists any value that lies both within the
// pattern and the constructor. These two cases reduce to intersection.
// If the constructor is a:
// Single value: add a row if the pattern contains the constructor.
// Range: add a row if the constructor intersects the pattern.
constructor_intersects_pattern(cx.tcx, constructor, pat)
}