[NI] Fix substitution of NotNullTypeParameter

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/components/NewTypeSubstitutor.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.resolve.calls.inference.components
@@ -122,6 +111,9 @@ interface NewTypeSubstitutor {
         if (type.isDefinitelyNotNullType) {
             replacement = replacement.makeDefinitelyNotNullOrNotNull()
         }
+        if (type is CustomTypeVariable) {
+            replacement = type.substitutionResult(replacement).unwrap()
+        }
 
         return replacement
     }