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Check for substs compatibility for RPITITs

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This commit is contained in:
Michael Goulet 2022-11-01 01:34:59 +00:00
parent 95a3a7277b
commit a2037e3012
3 changed files with 44 additions and 3 deletions
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18
compiler/rustc_trait_selection/src/traits/project.rs
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@ -2192,7 +2192,7 @@ fn confirm_impl_candidate<'cx, 'tcx>(
// Verify that the trait item and its implementation have compatible substs lists
fn check_substs_compatible<'tcx>(
tcx: TyCtxt<'tcx>,
assoc_ty: &ty::AssocItem,
assoc_item: &ty::AssocItem,
substs: ty::SubstsRef<'tcx>,
) -> bool {
fn check_substs_compatible_inner<'tcx>(
@ -2224,7 +2224,10 @@ fn check_substs_compatible<'tcx>(
true
}
check_substs_compatible_inner(tcx, tcx.generics_of(assoc_ty.def_id), substs.as_slice())
let generics = tcx.generics_of(assoc_item.def_id);
// Chop off any additional substs (RPITIT) substs
let substs = &substs[0..generics.count().min(substs.len())];
check_substs_compatible_inner(tcx, generics, substs)
}
fn confirm_impl_trait_in_trait_candidate<'tcx>(
@ -2253,12 +2256,21 @@ fn confirm_impl_trait_in_trait_candidate<'tcx>(
};
}
let impl_fn_def_id = leaf_def.item.def_id;
// Rebase from {trait}::{fn}::{opaque} to {impl}::{fn}::{opaque},
// since `data.substs` are the impl substs.
let impl_fn_substs =
obligation.predicate.substs.rebase_onto(tcx, tcx.parent(trait_fn_def_id), data.substs);
if !check_substs_compatible(tcx, &leaf_def.item, impl_fn_substs) {
let err = tcx.ty_error_with_message(
obligation.cause.span,
"impl method and trait method have different parameters",
);
return Progress { term: err.into(), obligations };
}
let impl_fn_def_id = leaf_def.item.def_id;
let cause = ObligationCause::new(
obligation.cause.span,
obligation.cause.body_id,