bjoernager/rust
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introduce a "comparison fn" instead of always use ==

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This commit is contained in:
Niko Matsakis 2018-09-17 13:03:34 -04:00
parent 9b63dcc773
commit db0e62692e
1 changed files with 10 additions and 11 deletions
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21
src/librustc/infer/outlives/verify.rs
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@ -153,7 +153,10 @@ impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
// like `<T as Foo<'a>>::Item`. // like `<T as Foo<'a>>::Item`.
let generic_ty = generic.to_ty(tcx); let generic_ty = generic.to_ty(tcx);
let c_b = self.param_env.caller_bounds; let c_b = self.param_env.caller_bounds;
let mut param_bounds = self.collect_outlives_from_predicate_list(generic_ty, c_b); let mut param_bounds = self.collect_outlives_from_predicate_list(
|ty| ty == generic_ty,
c_b,
);
// Next, collect regions we scraped from the well-formedness // Next, collect regions we scraped from the well-formedness
// constraints in the fn signature. To do that, we walk the list // constraints in the fn signature. To do that, we walk the list
@ -241,7 +244,7 @@ impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
let identity_substs = Substs::identity_for_item(tcx, assoc_item_def_id); let identity_substs = Substs::identity_for_item(tcx, assoc_item_def_id);
let identity_proj = tcx.mk_projection(assoc_item_def_id, identity_substs); let identity_proj = tcx.mk_projection(assoc_item_def_id, identity_substs);
self.collect_outlives_from_predicate_list( self.collect_outlives_from_predicate_list(
identity_proj, |ty| ty == identity_proj,
traits::elaborate_predicates(tcx, trait_predicates.predicates), traits::elaborate_predicates(tcx, trait_predicates.predicates),
) )
} }
@ -252,20 +255,16 @@ impl<'cx, 'gcx, 'tcx> VerifyBoundCx<'cx, 'gcx, 'tcx> {
/// when comparing `ty` for equality, so `ty` must be something /// when comparing `ty` for equality, so `ty` must be something
/// that does not involve inference variables and where you /// that does not involve inference variables and where you
/// otherwise want a precise match. /// otherwise want a precise match.
fn collect_outlives_from_predicate_list<I, P>( fn collect_outlives_from_predicate_list(
&self, &self,
ty: Ty<'tcx>, compare_ty: impl Fn(Ty<'tcx>) -> bool,
predicates: I, predicates: impl IntoIterator<Item = impl AsRef<ty::Predicate<'tcx>>>,
) -> Vec<ty::Region<'tcx>> ) -> Vec<ty::Region<'tcx>> {
where
I: IntoIterator<Item = P>,
P: AsRef<ty::Predicate<'tcx>>,
{
predicates predicates
.into_iter() .into_iter()
.filter_map(|p| p.as_ref().to_opt_type_outlives()) .filter_map(|p| p.as_ref().to_opt_type_outlives())
.filter_map(|p| p.no_late_bound_regions()) .filter_map(|p| p.no_late_bound_regions())
.filter(|p| p.0 == ty) .filter(|p| compare_ty(p.0))
.map(|p| p.1) .map(|p| p.1)
.collect() .collect()
} }