fix: skip cast if Ctor has an invalid type

compiler/rustc_hir_analysis/src/collect/type_of.rs

@@ -483,9 +483,16 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<Ty
             VariantData::Unit(..) | VariantData::Struct(..) => {
                 tcx.type_of(tcx.hir().get_parent_item(hir_id)).subst_identity()
             }
-            VariantData::Tuple(..) => {
-                let substs = InternalSubsts::identity_for_item(tcx, def_id);
-                Ty::new_fn_def(tcx, def_id.to_def_id(), substs)
+            VariantData::Tuple(fields, ..) => {
+                if let Some(Err(error)) = fields.iter().find_map(|field| {
+                    let field_ty = tcx.type_of(field.def_id).skip_binder();
+                    field_ty.references_error().then_some(field_ty.error_reported())
+                }) {
+                    Ty::new_error(tcx, error)
+                } else {
+                    let substs = InternalSubsts::identity_for_item(tcx, def_id);
+                    Ty::new_fn_def(tcx, def_id.to_def_id(), substs)
+                }
             }
         },
 

tests/ui/cast/issue-112630.rs

@@ -0,0 +1,7 @@
+enum Foo {
+    Bar(B) //~ ERROR cannot find type `B` in this scope [E0412]
+}
+
+fn main() {
+    let _ = [0; Foo::Bar as usize];
+}

tests/ui/cast/issue-112630.stderr

@@ -0,0 +1,14 @@
+error[E0412]: cannot find type `B` in this scope
+  --> $DIR/issue-112630.rs:2:9
+   |
+LL |     Bar(B)
+   |         ^ not found in this scope
+   |
+help: you might be missing a type parameter
+   |
+LL | enum Foo<B> {
+   |         +++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.