bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Rollup merge of #119385 - fmease:assoc-const-eq-fixes-2, r=oli-obk,cjgillot

Browse source 
Fix type resolution of associated const equality bounds (take 2)

Instead of trying to re-resolve the type of assoc const bindings inside the `type_of` query impl in an incomplete manner, transfer the already (correctly) resolved type from `add_predicates_for_ast_type_binding` to `type_of`/`anon_type_of` through query feeding.

---

Together with #118668 (merged) and #121258, this supersedes #118360.
Fixes #118040.

r? ``@ghost``
This commit is contained in:
Jubilee 2024-03-11 09:29:33 -07:00 • committed by GitHub
commit a4503390ba
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
5 changed files with 56 additions and 40 deletions
Download patch file Download diff file Expand all files Collapse all files

22
compiler/rustc_hir_analysis/src/astconv/bounds.rs
View file

@ -408,7 +408,7 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
// Create the generic arguments for the associated type or constant by joining the
// parent arguments (the arguments of the trait) and the own arguments (the ones of
// the associated item itself) and construct an alias type using them.
candidate.map_bound(|trait_ref| {
let alias_ty = candidate.map_bound(|trait_ref| {
let ident = Ident::new(assoc_item.name, binding.ident.span);
let item_segment = hir::PathSegment {
ident,
@ -430,7 +430,25 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
// *constants* to represent *const projections*. Alias *term* would be a more
// appropriate name but alas.
ty::AliasTy::new(tcx, assoc_item.def_id, alias_args)
})
});
// Provide the resolved type of the associated constant to `type_of(AnonConst)`.
if !speculative
&& let hir::TypeBindingKind::Equality { term: hir::Term::Const(anon_const) } =
binding.kind
{
let ty = alias_ty.map_bound(|ty| tcx.type_of(ty.def_id).instantiate(tcx, ty.args));
// Since the arguments passed to the alias type above may contain early-bound
// generic parameters, the instantiated type may contain some as well.
// Therefore wrap it in `EarlyBinder`.
// FIXME(fmease): Reject escaping late-bound vars.
tcx.feed_anon_const_type(
anon_const.def_id,
ty::EarlyBinder::bind(ty.skip_binder()),
);
}
alias_ty
};
match binding.kind {

31
compiler/rustc_hir_analysis/src/collect/type_of.rs
View file

@ -79,37 +79,6 @@ fn anon_const_type_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Ty<'tcx> {
.expect("const parameter types cannot be generic");
}
Node::TypeBinding(binding @ &TypeBinding { hir_id: binding_id, .. })
if let Node::TraitRef(trait_ref) = tcx.parent_hir_node(binding_id) =>
{
let Some(trait_def_id) = trait_ref.trait_def_id() else {
return Ty::new_error_with_message(
tcx,
tcx.def_span(def_id),
"Could not find trait",
);
};
let assoc_items = tcx.associated_items(trait_def_id);
let assoc_item = assoc_items.find_by_name_and_kind(
tcx,
binding.ident,
ty::AssocKind::Const,
def_id.to_def_id(),
);
return if let Some(assoc_item) = assoc_item {
tcx.type_of(assoc_item.def_id)
.no_bound_vars()
.expect("const parameter types cannot be generic")
} else {
// FIXME(associated_const_equality): add a useful error message here.
Ty::new_error_with_message(
tcx,
tcx.def_span(def_id),
"Could not find associated const on trait",
)
};
}
// This match arm is for when the def_id appears in a GAT whose
// path can't be resolved without typechecking e.g.
//