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Extract leak check into a distinct subroutine.

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This commit is contained in:
Niko Matsakis 2014-12-10 18:27:04 -05:00
parent 885f7ee12e
commit 1b24602ca0
1 changed files with 32 additions and 18 deletions
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50
src/librustc/middle/infer/higher_ranked/mod.rs
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@ -84,30 +84,17 @@ impl<'tcx,C> HigherRankedRelations<'tcx> for C
// Presuming type comparison succeeds, we need to check
// that the skolemized regions do not "leak".
let new_vars = self.infcx().region_vars_confined_to_snapshot(snapshot);
for (&skol_br, &skol) in skol_map.iter() {
let tainted = self.infcx().tainted_regions(snapshot, skol);
for tainted_region in tainted.iter() {
// Each skolemized should only be relatable to itself
// or new variables:
match *tainted_region {
ty::ReInfer(ty::ReVar(ref vid)) => {
if new_vars.iter().any(|x| x == vid) { continue; }
}
_ => {
if *tainted_region == skol { continue; }
}
};
// A is not as polymorphic as B:
match leak_check(self.infcx(), &skol_map, snapshot) {
Ok(()) => { }
Err((skol_br, tainted_region)) => {
if self.a_is_expected() {
debug!("Not as polymorphic!");
return Err(ty::terr_regions_insufficiently_polymorphic(skol_br,
*tainted_region));
tainted_region));
} else {
debug!("Overly polymorphic!");
return Err(ty::terr_regions_overly_polymorphic(skol_br,
*tainted_region));
tainted_region));
}
}
}
@ -548,3 +535,30 @@ fn skolemize_regions<'a,'tcx,HR>(infcx: &InferCtxt<'a,'tcx>,
skol
})
}
fn leak_check<'a,'tcx>(infcx: &InferCtxt<'a,'tcx>,
skol_map: &FnvHashMap<ty::BoundRegion,ty::Region>,
snapshot: &CombinedSnapshot)
-> Result<(),(ty::BoundRegion,ty::Region)>
{
let new_vars = infcx.region_vars_confined_to_snapshot(snapshot);
for (&skol_br, &skol) in skol_map.iter() {
let tainted = infcx.tainted_regions(snapshot, skol);
for &tainted_region in tainted.iter() {
// Each skolemized should only be relatable to itself
// or new variables:
match tainted_region {
ty::ReInfer(ty::ReVar(vid)) => {
if new_vars.iter().any(|&x| x == vid) { continue; }
}
_ => {
if tainted_region == skol { continue; }
}
};
// A is not as polymorphic as B:
return Err((skol_br, tainted_region));
}
}
Ok(())
}