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auto merge of #15081 : jakub-/rust/issue-15080, r=alexcrichton

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Fixes #15080.
This commit is contained in:
bors 2014-06-22 21:31:39 +00:00
commit ca3e557ee8
3 changed files with 54 additions and 10 deletions
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26
src/librustc/middle/check_match.rs
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@ -281,21 +281,27 @@ fn missing_constructor(cx: &MatchCheckCtxt, m: &Matrix, left_ty: ty::t) -> Optio
}
fn all_constructors(cx: &MatchCheckCtxt, m: &Matrix, left_ty: ty::t) -> Vec<ctor> {
// This produces a list of all vector constructors that we would expect to appear
// in an exhaustive set of patterns. Because such a list would normally be infinite,
// we narrow it down to only those constructors that actually appear in the inspected
// column, plus, any that are missing and not covered by a pattern with a destructured slice.
fn vec_constructors(m: &Matrix) -> Vec<ctor> {
let max_vec_len = m.iter().map(|r| match r.get(0).node {
PatVec(ref before, _, ref after) => before.len() + after.len(),
_ => 0u
}).max().unwrap_or(0u);
let contains_slice = m.iter().any(|r| match r.get(0).node {
PatVec(_, ref slice, _) => slice.is_some(),
_ => false
});
let lengths = iter::range_inclusive(0u, if contains_slice {
max_vec_len
} else {
max_vec_len + 1
});
lengths.map(|len| vec(len)).collect()
let min_vec_len_with_slice = m.iter().map(|r| match r.get(0).node {
PatVec(ref before, Some(_), ref after) => before.len() + after.len(),
_ => max_vec_len + 1
}).min().unwrap_or(max_vec_len + 1);
let other_lengths = m.iter().map(|r| match r.get(0).node {
PatVec(ref before, _, ref after) => before.len() + after.len(),
_ => 0u
}).filter(|&len| len > min_vec_len_with_slice);
iter::range_inclusive(0u, min_vec_len_with_slice)
.chain(other_lengths)
.map(|len| vec(len))
.collect()
}
match ty::get(left_ty).sty {