mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Remove manual normalization in compare_projection_bounds

Browse Source
This commit is contained in:
Tyler Mandry 2020-07-25 13:48:29 -07:00
parent 83a9dc92d5
commit 31a3bb59ce
3 changed files with 25 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
src/librustc_typeck/check/compare_method.rs
View File

@ -6,15 +6,14 @@ use rustc_hir::{GenericParamKind, ImplItemKind, TraitItemKind};
use rustc_infer::infer::{self, InferOk, TyCtxtInferExt};
use rustc_middle::ty;
use rustc_middle::ty::error::{ExpectedFound, TypeError};
use rustc_middle::ty::subst::{InternalSubsts, Subst, SubstsRef};
use rustc_middle::ty::subst::{InternalSubsts, Subst};
use rustc_middle::ty::util::ExplicitSelf;
use rustc_middle::ty::{GenericParamDefKind, ToPredicate, TyCtxt, WithConstness};
use rustc_middle::ty::{GenericParamDefKind, ToPredicate, TyCtxt};
use rustc_span::Span;
use rustc_trait_selection::traits::error_reporting::InferCtxtExt;
use rustc_trait_selection::traits::{self, ObligationCause, ObligationCauseCode, Reveal};
use super::{potentially_plural_count, FnCtxt, Inherited};
use std::iter;
/// Checks that a method from an impl conforms to the signature of
/// the same method as declared in the trait.
@ -1240,22 +1239,6 @@ fn compare_projection_bounds<'tcx>(
ty::ParamEnv::new(tcx.intern_predicates(&predicates), Reveal::UserFacing, None)
};
// Map the predicate from the trait to the corresponding one for the impl.
// For example:
//
// trait X<A> { type Y<'a>: PartialEq<A> } impl X for T { type Y<'a> = &'a S; }
// impl<'x> X<&'x u32> for () { type Y<'c> = &'c u32; }
//
// For the `for<'a> <<Self as X<A>>::Y<'a>: PartialEq<A>` bound, this
// function would translate and partially normalize
// `[<Self as X<A>>::Y<'a>, A]` to `[&'a u32, &'x u32]`.
let translate_predicate_substs = move |predicate_substs: SubstsRef<'tcx>| {
tcx.mk_substs(
iter::once(impl_ty_value.into())
.chain(predicate_substs[1..].iter().map(|s| s.subst(tcx, rebased_substs))),
)
};
tcx.infer_ctxt().enter(move |infcx| {
let inh = Inherited::new(infcx, impl_ty.def_id.expect_local());
let infcx = &inh.infcx;
@ -1270,39 +1253,10 @@ fn compare_projection_bounds<'tcx>(
);
let predicates = tcx.projection_predicates(trait_ty.def_id);
debug!("compare_projection_bounds: projection_predicates={:?}", predicates);
for predicate in predicates {
let concrete_ty_predicate = match predicate.kind() {
ty::PredicateKind::Trait(poly_tr, c) => poly_tr
.map_bound(|tr| {
let trait_substs = translate_predicate_substs(tr.trait_ref.substs);
ty::TraitRef { def_id: tr.def_id(), substs: trait_substs }
})
.with_constness(*c)
.to_predicate(tcx),
ty::PredicateKind::Projection(poly_projection) => poly_projection
.map_bound(|projection| {
let projection_substs =
translate_predicate_substs(projection.projection_ty.substs);
ty::ProjectionPredicate {
projection_ty: ty::ProjectionTy {
substs: projection_substs,
item_def_id: projection.projection_ty.item_def_id,
},
ty: projection.ty.subst(tcx, rebased_substs),
}
})
.to_predicate(tcx),
ty::PredicateKind::TypeOutlives(poly_outlives) => poly_outlives
.map_bound(|outlives| {
ty::OutlivesPredicate(impl_ty_value, outlives.1.subst(tcx, rebased_substs))
})
.to_predicate(tcx),
_ => bug!("unexepected projection predicate kind: `{:?}`", predicate),
};
let concrete_ty_predicate = predicate.subst(tcx, rebased_substs);
debug!("compare_projection_bounds: concrete predicate = {:?}", concrete_ty_predicate);
let traits::Normalized { value: normalized_predicate, obligations } = traits::normalize(
@ -1311,7 +1265,6 @@ fn compare_projection_bounds<'tcx>(
normalize_cause.clone(),
&concrete_ty_predicate,
);
debug!("compare_projection_bounds: normalized predicate = {:?}", normalized_predicate);
inh.register_predicates(obligations);

2
src/test/ui/generic-associated-types/unsatisfied-outlives-bound.rs
View File

@ -7,7 +7,7 @@ trait ATy {
impl<'b> ATy for &'b () {
type Item<'a> = &'b ();
//~^ ERROR does not fulfill the required lifetime
//~^ ERROR cannot infer an appropriate lifetime
}
trait StaticTy {

24
src/test/ui/generic-associated-types/unsatisfied-outlives-bound.stderr
View File

@ -1,14 +1,31 @@
error[E0477]: the type `&'b ()` does not fulfill the required lifetime
error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'b` due to conflicting requirements
--> $DIR/unsatisfied-outlives-bound.rs:9:5
|
LL | type Item<'a> = &'b ();
| ^^^^^^^^^^^^^^^^^^^^^^^
|
note: type must outlive the lifetime `'a` as defined on the associated item at 9:15
note: first, the lifetime cannot outlive the lifetime `'b` as defined on the impl at 8:6...
--> $DIR/unsatisfied-outlives-bound.rs:8:6
|
LL | impl<'b> ATy for &'b () {
| ^^
note: ...so that the types are compatible
--> $DIR/unsatisfied-outlives-bound.rs:9:5
|
LL | type Item<'a> = &'b ();
| ^^^^^^^^^^^^^^^^^^^^^^^
= note: expected `ATy`
found `ATy`
note: but, the lifetime must be valid for the lifetime `'a` as defined on the associated item at 9:15...
--> $DIR/unsatisfied-outlives-bound.rs:9:15
|
LL | type Item<'a> = &'b ();
| ^^
note: ...so that the type `&()` will meet its required lifetime bounds
--> $DIR/unsatisfied-outlives-bound.rs:9:5
|
LL | type Item<'a> = &'b ();
| ^^^^^^^^^^^^^^^^^^^^^^^
error[E0477]: the type `&'a ()` does not fulfill the required lifetime
--> $DIR/unsatisfied-outlives-bound.rs:18:5
@ -20,4 +37,5 @@ LL | type Item<'a> = &'a ();
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0477`.
Some errors have detailed explanations: E0477, E0495.
For more information about an error, try `rustc --explain E0477`.