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Fix #8391 #14171

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Fix #8391 #14171

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ef6beb3
Fix #8391
edwardw May 13, 2014
a83a3c5
check_match: get rid of superfluous clones
edwardw May 13, 2014
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65 changes: 30 additions & 35 deletions src/librustc/middle/check_match.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -239,7 +239,15 @@ fn is_useful(cx: &MatchCheckCtxt, m: &matrix, v: &[@Pat]) -> useful {
return not_useful
}
let real_pat = match m.iter().find(|r| r.get(0).id != 0) {
Some(r) => *r.get(0), None => v[0]
Some(r) => {
match r.get(0).node {
// An arm of the form `ref x @ sub_pat` has type
// `sub_pat`, not `&sub_pat` as `x` itself does.
PatIdent(BindByRef(_), _, Some(sub)) => sub,
_ => *r.get(0)
}
}
None => v[0]
};
let left_ty = if real_pat.id == 0 { ty::mk_nil() }
else { ty::node_id_to_type(cx.tcx, real_pat.id) };
Expand All @@ -258,15 +266,15 @@ fn is_useful(cx: &MatchCheckCtxt, m: &matrix, v: &[@Pat]) -> useful {
val(const_bool(false)),
0u, left_ty)
}
ref u => (*u).clone(),
u => u,
}
}
ty::ty_enum(eid, _) => {
for va in (*ty::enum_variants(cx.tcx, eid)).iter() {
match is_useful_specialized(cx, m, v, variant(va.id),
va.args.len(), left_ty) {
not_useful => (),
ref u => return (*u).clone(),
u => return u,
}
}
not_useful
Expand All @@ -288,7 +296,7 @@ fn is_useful(cx: &MatchCheckCtxt, m: &matrix, v: &[@Pat]) -> useful {
for n in iter::range(0u, max_len + 1) {
match is_useful_specialized(cx, m, v, vec(n), n, left_ty) {
not_useful => (),
ref u => return (*u).clone(),
u => return u,
}
}
not_useful
Expand All @@ -304,21 +312,21 @@ fn is_useful(cx: &MatchCheckCtxt, m: &matrix, v: &[@Pat]) -> useful {
}
}
}
Some(ref ctor) => {
Some(ctor) => {
match is_useful(cx,
&m.iter().filter_map(|r| {
default(cx, r.as_slice())
}).collect::<matrix>(),
v.tail()) {
useful_ => useful(left_ty, (*ctor).clone()),
ref u => (*u).clone(),
useful_ => useful(left_ty, ctor),
u => u,
}
}
}
}
Some(ref v0_ctor) => {
let arity = ctor_arity(cx, v0_ctor, left_ty);
is_useful_specialized(cx, m, v, (*v0_ctor).clone(), arity, left_ty)
Some(v0_ctor) => {
let arity = ctor_arity(cx, &v0_ctor, left_ty);
is_useful_specialized(cx, m, v, v0_ctor, arity, left_ty)
}
}
}
Expand All @@ -337,7 +345,7 @@ fn is_useful_specialized(cx: &MatchCheckCtxt,
cx, &ms, specialize(cx, v, &ctor, arity, lty).unwrap().as_slice());
match could_be_useful {
useful_ => useful(lty, ctor),
ref u => (*u).clone(),
u => u,
}
}

Expand Down Expand Up @@ -408,9 +416,9 @@ fn missing_ctor(cx: &MatchCheckCtxt,
let mut found = Vec::new();
for r in m.iter() {
let r = pat_ctor_id(cx, *r.get(0));
for id in r.iter() {
if !found.contains(id) {
found.push((*id).clone());
for id in r.move_iter() {
if !found.contains(&id) {
found.push(id);
}
}
}
Expand Down Expand Up @@ -812,30 +820,17 @@ fn specialize(cx: &MatchCheckCtxt,
let num_elements = before.len() + after.len();
if num_elements < arity && slice.is_some() {
let mut result = Vec::new();
for pat in before.iter() {
result.push((*pat).clone());
}
for _ in iter::range(0, arity - num_elements) {
result.push(wild())
}
for pat in after.iter() {
result.push((*pat).clone());
}
for pat in r.tail().iter() {
result.push((*pat).clone());
}
let wilds = Vec::from_elem(arity - num_elements, wild());
result.push_all_move(before);
result.push_all_move(wilds);
result.push_all_move(after);
result.push_all(r.tail());
Some(result)
} else if num_elements == arity {
let mut result = Vec::new();
for pat in before.iter() {
result.push((*pat).clone());
}
for pat in after.iter() {
result.push((*pat).clone());
}
for pat in r.tail().iter() {
result.push((*pat).clone());
}
result.push_all_move(before);
result.push_all_move(after);
result.push_all(r.tail());
Some(result)
} else {
None
Expand Down
5 changes: 3 additions & 2 deletions src/test/run-pass/issue-8391.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,8 +9,9 @@
// except according to those terms.

fn main() {
let _x = match Some(1) {
_y @ Some(_) => 1,
let x = match Some(1) {
ref _y @ Some(_) => 1,
None => 2,
};
assert_eq!(x, 1);
}