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| author | Ellen <supbscripter@gmail.com> | 2021-02-10 05:15:35 +0000 |
|---|---|---|
| committer | Ellen <supbscripter@gmail.com> | 2021-02-10 05:15:43 +0000 |
| commit | 2c4337a70a4d4451fc440b1bb60ff5ca8b7eb5b2 (patch) | |
| tree | 3f73aaf5484fe53ef6bffc03b61a4a204e725724 | |
| parent | 1d9ac3c22c98b468eb3d6c9770f1ab4be782dc74 (diff) | |
| download | rust-2c4337a70a4d4451fc440b1bb60ff5ca8b7eb5b2.tar.gz rust-2c4337a70a4d4451fc440b1bb60ff5ca8b7eb5b2.zip | |
Comments :3
| -rw-r--r-- | compiler/rustc_typeck/src/collect/type_of.rs | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/compiler/rustc_typeck/src/collect/type_of.rs b/compiler/rustc_typeck/src/collect/type_of.rs index ef17ab9ccd1..b5f37c8398e 100644 --- a/compiler/rustc_typeck/src/collect/type_of.rs +++ b/compiler/rustc_typeck/src/collect/type_of.rs @@ -29,19 +29,32 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option< let parent_node = tcx.hir().get(parent_node_id); match parent_node { + // This matches on types who's paths couldn't be resolved without typeck'ing e.g. + // + // trait Foo { + // type Assoc<const N1: usize>;; + // fn foo() -> Self::Assoc<3>; + // // note: if the def_id argument is the 3 then in this example + // // parent_node would be the node for Self::Assoc<_> + // } + // We didnt write <Self as Foo>::Assoc so the Self::Assoc<_> is lowered to QPath::TypeRelative. + // I believe this match arm is only needed for GAT but I am not 100% sure - BoxyUwU Node::Ty(hir_ty @ Ty { kind: TyKind::Path(QPath::TypeRelative(_, segment)), .. }) => { - let id = tcx + // Walk up from the parent_node to find an item so that + // we can resolve the relative path to an actual associated type + let item_hir_id = tcx .hir() .parent_iter(hir_id) .filter(|(_, node)| matches!(node, Node::Item(_))) .map(|(id, _)| id) .next() .unwrap(); - - let item_did = tcx.hir().local_def_id(id).to_def_id(); + let item_did = tcx.hir().local_def_id(item_hir_id).to_def_id(); let item_ctxt = &ItemCtxt::new(tcx, item_did) as &dyn crate::astconv::AstConv<'_>; - let ty = item_ctxt.ast_ty_to_ty(hir_ty); + // This ty will be the actual associated type so that we can + // go through its generics to find which param our def_id corresponds to + let ty = item_ctxt.ast_ty_to_ty(hir_ty); if let ty::Projection(projection) = ty.kind() { let generics = tcx.generics_of(projection.item_def_id); @@ -65,6 +78,7 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option< .map(|param| param.def_id); } + // I dont think it's possible to reach this but I'm not 100% sure - BoxyUwU tcx.sess.delay_span_bug( tcx.def_span(def_id), "unexpected non-GAT usage of an anon const", |