Permit recursive weak type aliases

1 files changed, 12 insertions, 7 deletions

diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs
index 668763f9bf6..7a6856fb1f4 100644
--- a/compiler/rustc_hir_analysis/src/astconv/mod.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs
@@ -910,19 +910,24 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     ) -> Ty<'tcx> {
         let tcx = self.tcx();
         let args = self.ast_path_args_for_ty(span, did, item_segment);
-        let ty = tcx.at(span).type_of(did);
 
-        if let DefKind::TyAlias { lazy } = tcx.def_kind(did)
-            && (lazy || ty.skip_binder().has_opaque_types())
-        {
-            // Type aliases referring to types that contain opaque types (but aren't just directly
-            // referencing a single opaque type) as well as those defined in crates that have the
+        if let DefKind::TyAlias { lazy: true } = tcx.def_kind(did) {
+            // Type aliases defined in crates that have the
             // feature `lazy_type_alias` enabled get encoded as a type alias that normalization will
             // then actually instantiate the where bounds of.
             let alias_ty = tcx.mk_alias_ty(did, args);
             Ty::new_alias(tcx, ty::Weak, alias_ty)
         } else {
-            ty.instantiate(tcx, args)
+            let ty = tcx.at(span).type_of(did);
+            if ty.skip_binder().has_opaque_types() {
+                // Type aliases referring to types that contain opaque types (but aren't just directly
+                // referencing a single opaque type) get encoded as a type alias that normalization will
+                // then actually instantiate the where bounds of.
+                let alias_ty = tcx.mk_alias_ty(did, args);
+                Ty::new_alias(tcx, ty::Weak, alias_ty)
+            } else {
+                ty.instantiate(tcx, args)
+            }
         }
     }