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Move trait_ref_to_existential to a closure

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This commit is contained in:
Esteban Küber 2019-11-17 14:57:06 -08:00
parent 8d1c2612f8
commit 0ff73535ed
1 changed files with 19 additions and 21 deletions
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40
src/librustc_typeck/astconv.rs
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@ -1224,25 +1224,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
)
}
/// Transform a `PolyTraitRef` into a `PolyExistentialTraitRef` by
/// removing the dummy `Self` type (`trait_object_dummy_self`).
fn trait_ref_to_existential(
&self,
trait_ref: ty::TraitRef<'tcx>,
) -> ty::ExistentialTraitRef<'tcx> {
if trait_ref.self_ty() != self.tcx().types.trait_object_dummy_self {
// FIXME: There appears to be a missing filter on top of `expand_trait_aliases`, which
// picks up non-supertraits where clauses - but also, the object safety completely
// ignores trait aliases, which could be object safety hazards. We `delay_span_bug`
// here to avoid an ICE in stable even when the feature is disabled. (#66420)
self.tcx().sess.delay_span_bug(DUMMY_SP, &format!(
"trait_ref_to_existential called on {:?} with non-dummy Self",
trait_ref,
));
}
ty::ExistentialTraitRef::erase_self_ty(self.tcx(), trait_ref)
}
fn conv_object_ty_poly_trait_ref(&self,
span: Span,
trait_bounds: &[hir::PolyTraitRef],
@ -1424,13 +1405,30 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
debug!("regular_traits: {:?}", regular_traits);
debug!("auto_traits: {:?}", auto_traits);
// Transform a `PolyTraitRef` into a `PolyExistentialTraitRef` by
// removing the dummy `Self` type (`trait_object_dummy_self`).
let trait_ref_to_existential = |trait_ref: ty::TraitRef<'tcx>| {
if trait_ref.self_ty() != dummy_self {
// FIXME: There appears to be a missing filter on top of `expand_trait_aliases`,
// which picks up non-supertraits where clauses - but also, the object safety
// completely ignores trait aliases, which could be object safety hazards. We
// `delay_span_bug` here to avoid an ICE in stable even when the feature is
// disabled. (#66420)
tcx.sess.delay_span_bug(DUMMY_SP, &format!(
"trait_ref_to_existential called on {:?} with non-dummy Self",
trait_ref,
));
}
ty::ExistentialTraitRef::erase_self_ty(tcx, trait_ref)
};
// Erase the `dummy_self` (`trait_object_dummy_self`) used above.
let existential_trait_refs = regular_traits.iter().map(|i| {
i.trait_ref().map_bound(|trait_ref| self.trait_ref_to_existential(trait_ref))
i.trait_ref().map_bound(|trait_ref| trait_ref_to_existential(trait_ref))
});
let existential_projections = bounds.projection_bounds.iter().map(|(bound, _)| {
bound.map_bound(|b| {
let trait_ref = self.trait_ref_to_existential(b.projection_ty.trait_ref(tcx));
let trait_ref = trait_ref_to_existential(b.projection_ty.trait_ref(tcx));
ty::ExistentialProjection {
ty: b.ty,
item_def_id: b.projection_ty.item_def_id,