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make compare_const_impl a query and use it in instance.rs

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This commit is contained in:
Boxy 2022-09-30 17:47:39 +01:00
parent f914b82a75
commit 86a8a3beb4
9 changed files with 120 additions and 86 deletions
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38
compiler/rustc_ty_utils/src/instance.rs
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@ -182,40 +182,18 @@ fn resolve_associated_item<'tcx>(
// a `trait` to an associated `const` definition in an `impl`, where
// the definition in the `impl` has the wrong type (for which an
// error has already been/will be emitted elsewhere).
//
// NB: this may be expensive, we try to skip it in all the cases where
// we know the error would've been caught (e.g. in an upstream crate).
//
// A better approach might be to just introduce a query (returning
// `Result<(), ErrorGuaranteed>`) for the check that `rustc_hir_analysis`
// performs (i.e. that the definition's type in the `impl` matches
// the declaration in the `trait`), so that we can cheaply check
// here if it failed, instead of approximating it.
if leaf_def.item.kind == ty::AssocKind::Const
&& trait_item_id != leaf_def.item.def_id
&& leaf_def.item.def_id.is_local()
{
let normalized_type_of = |def_id, substs| {
tcx.subst_and_normalize_erasing_regions(substs, param_env, tcx.type_of(def_id))
};
let original_ty = normalized_type_of(trait_item_id, rcvr_substs);
let resolved_ty = normalized_type_of(leaf_def.item.def_id, substs);
if original_ty != resolved_ty {
let msg = format!(
"Instance::resolve: inconsistent associated `const` type: \
was `{}: {}` but resolved to `{}: {}`",
tcx.def_path_str_with_substs(trait_item_id, rcvr_substs),
original_ty,
tcx.def_path_str_with_substs(leaf_def.item.def_id, substs),
resolved_ty,
);
let span = tcx.def_span(leaf_def.item.def_id);
let reported = tcx.sess.delay_span_bug(span, &msg);
return Err(reported);
}
let impl_item = tcx.associated_item(leaf_def.item.def_id);
let trait_item = tcx.associated_item(trait_item_id);
let impl_trait_ref = tcx.impl_trait_ref(impl_item.container_id(tcx)).unwrap();
tcx.compare_assoc_const_impl_item_with_trait_item((
impl_item,
trait_item,
impl_trait_ref,
))?;
}
Some(ty::Instance::new(leaf_def.item.def_id, substs))