ir.tree: fix return type of IrMemberAccessExpression.getTypeArgumentOrDefault

(cherry picked from commit 9e7661f)

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/IrMemberAccessExpression.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 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 2010-2018 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.ir.expressions
@@ -19,6 +8,7 @@ package org.jetbrains.kotlin.ir.expressions
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
 import org.jetbrains.kotlin.ir.types.IrType
+import org.jetbrains.kotlin.ir.types.toKotlinType
 import org.jetbrains.kotlin.types.KotlinType
 
 interface IrMemberAccessExpression : IrExpression {
@@ -68,7 +58,7 @@ val CallableDescriptor.typeParametersCount: Int
         }
 
 fun IrMemberAccessExpression.getTypeArgumentOrDefault(typeParameterDescriptor: TypeParameterDescriptor) =
-    getTypeArgument(typeParameterDescriptor) ?: typeParameterDescriptor.defaultType
+    getTypeArgument(typeParameterDescriptor)?.toKotlinType() ?: typeParameterDescriptor.defaultType
 
 interface IrFunctionAccessExpression : IrMemberAccessExpression, IrDeclarationReference {
     override val descriptor: FunctionDescriptor