bjoernager/rust
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Don't go through TraitRef to relate projections

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This commit is contained in:
Matthew Jasper 2021-02-12 22:07:46 +00:00
parent 9bbd3e0f8e
commit 0bf1d73d22
3 changed files with 42 additions and 18 deletions
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15
compiler/rustc_trait_selection/src/traits/project.rs
View file

@ -921,8 +921,7 @@ fn assemble_candidates_from_predicates<'cx, 'tcx>(
&& infcx.probe(|_| {
selcx.match_projection_projections(
obligation,
obligation_trait_ref,
&data,
data,
potentially_unnormalized_candidates,
)
});
@ -1344,25 +1343,25 @@ fn confirm_param_env_candidate<'cx, 'tcx>(
poly_cache_entry,
);
let cache_trait_ref = cache_entry.projection_ty.trait_ref(infcx.tcx);
let obligation_trait_ref = obligation.predicate.trait_ref(infcx.tcx);
let cache_projection = cache_entry.projection_ty;
let obligation_projection = obligation.predicate;
let mut nested_obligations = Vec::new();
let cache_trait_ref = if potentially_unnormalized_candidate {
let cache_projection = if potentially_unnormalized_candidate {
ensure_sufficient_stack(|| {
normalize_with_depth_to(
selcx,
obligation.param_env,
obligation.cause.clone(),
obligation.recursion_depth + 1,
cache_trait_ref,
cache_projection,
&mut nested_obligations,
)
})
} else {
cache_trait_ref
cache_projection
};
match infcx.at(cause, param_env).eq(cache_trait_ref, obligation_trait_ref) {
match infcx.at(cause, param_env).eq(cache_projection, obligation_projection) {
Ok(InferOk { value: _, obligations }) => {
nested_obligations.extend(obligations);
assoc_ty_own_obligations(selcx, obligation, &mut nested_obligations);

20
compiler/rustc_trait_selection/src/traits/select/mod.rs
View file

@ -32,6 +32,7 @@ use rustc_errors::ErrorReported;
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_hir::Constness;
use rustc_infer::infer::LateBoundRegionConversionTime;
use rustc_middle::dep_graph::{DepKind, DepNodeIndex};
use rustc_middle::mir::interpret::ErrorHandled;
use rustc_middle::ty::fast_reject;
@ -1254,32 +1255,33 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
pub(super) fn match_projection_projections(
&mut self,
obligation: &ProjectionTyObligation<'tcx>,
obligation_trait_ref: &ty::TraitRef<'tcx>,
data: &PolyProjectionPredicate<'tcx>,
env_predicate: PolyProjectionPredicate<'tcx>,
potentially_unnormalized_candidates: bool,
) -> bool {
let mut nested_obligations = Vec::new();
let projection_ty = if potentially_unnormalized_candidates {
let (infer_predicate, _) = self.infcx.replace_bound_vars_with_fresh_vars(
obligation.cause.span,
LateBoundRegionConversionTime::HigherRankedType,
env_predicate,
);
let infer_projection = if potentially_unnormalized_candidates {
ensure_sufficient_stack(|| {
project::normalize_with_depth_to(
self,
obligation.param_env,
obligation.cause.clone(),
obligation.recursion_depth + 1,
data.map_bound(|data| data.projection_ty),
infer_predicate.projection_ty,
&mut nested_obligations,
)
})
} else {
data.map_bound(|data| data.projection_ty)
infer_predicate.projection_ty
};
// FIXME(generic_associated_types): Compare the whole projections
let data_poly_trait_ref = projection_ty.map_bound(|proj| proj.trait_ref(self.tcx()));
let obligation_poly_trait_ref = ty::Binder::dummy(*obligation_trait_ref);
self.infcx
.at(&obligation.cause, obligation.param_env)
.sup(obligation_poly_trait_ref, data_poly_trait_ref)
.sup(obligation.predicate, infer_projection)
.map_or(false, |InferOk { obligations, value: () }| {
self.evaluate_predicates_recursively(
TraitObligationStackList::empty(&ProvisionalEvaluationCache::default()),