bjoernager/rust
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new fix method and update tests

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This commit is contained in:
Vishnunarayan K I 2020-11-02 22:29:20 +05:30
parent 9088807dd3
commit 6bdce7bedd
16 changed files with 143 additions and 135 deletions
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38
compiler/rustc_mir_build/src/build/matches/simplify.rs
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@ -44,6 +44,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
candidate: &mut Candidate<'pat, 'tcx>,
) -> bool {
// repeatedly simplify match pairs until fixed point is reached
debug!("simplify_candidate(candidate={:?})", candidate);
let mut new_bindings = Vec::new();
loop {
let match_pairs = mem::take(&mut candidate.match_pairs);
@ -56,7 +58,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
let mut changed = false;
for match_pair in match_pairs {
match self.simplify_match_pair(match_pair, candidate) {
match self.simplify_match_pair(match_pair, candidate, &mut new_bindings) {
Ok(()) => {
changed = true;
}
@ -65,6 +67,23 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
}
}
}
// issue #69971: the binding order should be right to left if there are more
// bindings after `@` to please the borrow checker
// Ex
// struct NonCopyStruct {
// copy_field: u32,
// }
//
// fn foo1(x: NonCopyStruct) {
// let y @ NonCopyStruct { copy_field: z } = x;
// // the above should turn into
// let z = x.copy_field;
// let y = x;
// }
new_bindings.extend_from_slice(&candidate.bindings);
mem::swap(&mut candidate.bindings, &mut new_bindings);
new_bindings.clear();
if !changed {
// Move or-patterns to the end, because they can result in us
// creating additional candidates, so we want to test them as
@ -72,6 +91,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
candidate
.match_pairs
.sort_by_key(|pair| matches!(*pair.pattern.kind, PatKind::Or { .. }));
debug!("simplify_candidate: simplifed {:?}", candidate);
return false; // if we were not able to simplify any, done.
}
}
@ -104,6 +124,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
&mut self,
match_pair: MatchPair<'pat, 'tcx>,
candidate: &mut Candidate<'pat, 'tcx>,
bindings: &mut Vec<Binding<'tcx>>,
) -> Result<(), MatchPair<'pat, 'tcx>> {
let tcx = self.hir.tcx();
match *match_pair.pattern.kind {
@ -131,20 +152,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
}
PatKind::Binding { name, mutability, mode, var, ty, ref subpattern, is_primary: _ } => {
// issue #69971: the binding order should be right to left if there are more
// bindings after `@` to please the borrow checker
// Ex
// struct NonCopyStruct {
// copy_field: u32,
// }
//
// fn foo1(x: NonCopyStruct) {
// let y @ NonCopyStruct { copy_field: z } = x;
// // the above should turn into
// let z = x.copy_field;
// let y = x;
// }
candidate.bindings.insert(0, Binding {
bindings.push(Binding {
name,
mutability,
span: match_pair.pattern.span,