[Tests] Add regression test for #KT-63732

compiler/testData/codegen/box/innerNested/kt63732.kt

@@ -0,0 +1,23 @@
+// IGNORE_BACKEND_K1: ANY
+// ^KT-63732
+
+lateinit var foo: Any
+
+class A<T : Any> {
+    inner class B(x: T) {
+        init {
+            foo = x
+        }
+    }
+
+    fun foo(t: T) {
+        object {
+            val something: B = B(t)
+        }
+    }
+}
+
+fun box(): String {
+    A<String>().foo("OK")
+    return foo as String
+}