delay bug in RPITIT refinement checking with resolution errors

tests/ui/impl-trait/in-trait/refine-resolution-errors.rs

@@ -0,0 +1,23 @@
+// This is a non-regression test for issue #126670 where RPITIT refinement checking encountered
+// errors during resolution and ICEd.
+
+//@ edition: 2018
+
+pub trait Mirror {
+    type Assoc;
+}
+impl<T: ?Sized> Mirror for () {
+    //~^ ERROR the type parameter `T` is not constrained
+    type Assoc = T;
+}
+
+pub trait First {
+    async fn first() -> <() as Mirror>::Assoc;
+    //~^ ERROR type annotations needed
+}
+
+impl First for () {
+    async fn first() {}
+}
+
+fn main() {}