[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/tests/generics/kt5508.fir.kt

@@ -0,0 +1,24 @@
+// !WITH_NEW_INFERENCE
+// KT-5508 Stackoverflow in type substitution
+
+abstract class A<T> {
+    public abstract fun foo(x: T)
+    public abstract fun bar(x: T)
+
+    public inner abstract class B<S> : A<B<S>>() {
+        public inner class C<U> : B<C<U>>()
+        {
+            // Here B<C<U>> means A<A<A<T>.B<S>>.B<A<T>.B<S>.C<U>>>.B<A<A<T>.B<S>>.B<A<T>.B<S>.C<U>>.C<U>>
+            // while for being a correct override it should be A<A<T>.B<S>>.B<A<T>.B<S>.C<U>>
+            // It happens because at the beginning we search implicit arguments for an outer classes through supertypes
+            // See TypeResolver.computeImplicitOuterClassArguments for clarifications
+            override fun foo(x: B<C<U>>)  {
+                throw UnsupportedOperationException()
+            }
+
+            override fun bar(x: A<A<T>.B<S>>.B<A<T>.B<S>.C<U>>) {
+                throw UnsupportedOperationException()
+            }
+        }
+    }
+}