bug fixed: do not substitute type parameters twice

through final argument check

compiler/testData/diagnostics/tests/inference/opposite.kt

@@ -0,0 +1,11 @@
+package a
+
+trait Persistent
+trait PersistentFactory<T>
+
+class Relation<Source: Persistent, Target: Persistent>(
+        val sources: PersistentFactory<Source>,
+        val targets: PersistentFactory<Target>
+) {
+    fun opposite() = Relation(targets, sources)
+}