From c856c74764006610e23de4210a17dfb7a1702127 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Le=C3=B3n=20Orell=20Valerian=20Liehr?= <me@fmease.dev>
Date: Sun, 16 Jul 2023 12:38:43 +0200
Subject: [PATCH] Normalize lazy type aliases when probing for ADTs

---
 compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs    |  4 +++-
 .../type-alias/lazy-type-alias-enum-variant.rs  | 17 +++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 tests/ui/type-alias/lazy-type-alias-enum-variant.rs

diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
index 1e8af6c6ed7..6a82b00211e 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
@@ -302,7 +302,9 @@ fn probe_adt(&self, span: Span, ty: Ty<'tcx>) -> Option<ty::AdtDef<'tcx>> {
         match ty.kind() {
             ty::Adt(adt_def, _) => Some(*adt_def),
             // FIXME(#104767): Should we handle bound regions here?
-            ty::Alias(ty::Projection | ty::Inherent, _) if !ty.has_escaping_bound_vars() => {
+            ty::Alias(ty::Projection | ty::Inherent | ty::Weak, _)
+                if !ty.has_escaping_bound_vars() =>
+            {
                 self.normalize(span, ty).ty_adt_def()
             }
             _ => None,
diff --git a/tests/ui/type-alias/lazy-type-alias-enum-variant.rs b/tests/ui/type-alias/lazy-type-alias-enum-variant.rs
new file mode 100644
index 00000000000..78c3159d1c2
--- /dev/null
+++ b/tests/ui/type-alias/lazy-type-alias-enum-variant.rs
@@ -0,0 +1,17 @@
+// Regression test for issue #113736.
+// check-pass
+
+#![feature(lazy_type_alias)]
+
+enum Enum {
+    Unit,
+    Tuple(),
+    Struct {},
+}
+
+fn main() {
+    type Alias = Enum;
+    let _ = Alias::Unit;
+    let _ = Alias::Tuple();
+    let _ = Alias::Struct {};
+}