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Introduce DeepRejectCtxt::substs_refs_may_unify.

It factors out a repeated code pattern.
This commit is contained in:
Nicholas Nethercote 2023-03-07 15:42:50 +11:00
parent 478cbb42b7
commit 47225e8700
5 changed files with 23 additions and 17 deletions

View file

@ -17,7 +17,6 @@ use rustc_middle::ty::ProjectionPredicate;
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_middle::ty::{ToPredicate, TypeVisitableExt};
use rustc_span::{sym, DUMMY_SP};
use std::iter;
impl<'tcx> EvalCtxt<'_, 'tcx> {
#[instrument(level = "debug", skip(self), ret)]
@ -144,9 +143,7 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
let goal_trait_ref = goal.predicate.projection_ty.trait_ref(tcx);
let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::ForLookup };
if iter::zip(goal_trait_ref.substs, impl_trait_ref.skip_binder().substs)
.any(|(goal, imp)| !drcx.generic_args_may_unify(goal, imp))
{
if !drcx.substs_refs_may_unify(goal_trait_ref.substs, impl_trait_ref.skip_binder().substs) {
return Err(NoSolution);
}

View file

@ -1,7 +1,5 @@
//! Dealing with trait goals, i.e. `T: Trait<'a, U>`.
use std::iter;
use super::{assembly, EvalCtxt, SolverMode};
use rustc_hir::def_id::DefId;
use rustc_hir::LangItem;
@ -41,9 +39,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::ForLookup };
if iter::zip(goal.predicate.trait_ref.substs, impl_trait_ref.skip_binder().substs)
.any(|(goal, imp)| !drcx.generic_args_may_unify(goal, imp))
{
if !drcx.substs_refs_may_unify(
goal.predicate.trait_ref.substs,
impl_trait_ref.skip_binder().substs,
) {
return Err(NoSolution);
}

View file

@ -79,8 +79,9 @@ pub fn overlapping_impls(
let impl1_ref = tcx.impl_trait_ref(impl1_def_id);
let impl2_ref = tcx.impl_trait_ref(impl2_def_id);
let may_overlap = match (impl1_ref, impl2_ref) {
(Some(a), Some(b)) => iter::zip(a.skip_binder().substs, b.skip_binder().substs)
.all(|(arg1, arg2)| drcx.generic_args_may_unify(arg1, arg2)),
(Some(a), Some(b)) => {
drcx.substs_refs_may_unify(a.skip_binder().substs, b.skip_binder().substs)
}
(None, None) => {
let self_ty1 = tcx.type_of(impl1_def_id).skip_binder();
let self_ty2 = tcx.type_of(impl2_def_id).skip_binder();

View file

@ -2542,8 +2542,10 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
// substitution if we find that any of the input types, when
// simplified, do not match.
let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::ForLookup };
iter::zip(obligation.predicate.skip_binder().trait_ref.substs, impl_trait_ref.substs)
.any(|(obl, imp)| !drcx.generic_args_may_unify(obl, imp))
!drcx.substs_refs_may_unify(
obligation.predicate.skip_binder().trait_ref.substs,
impl_trait_ref.substs,
)
}
/// Normalize `where_clause_trait_ref` and try to match it against