Support overrides of generic methods with erased version in Java

core/descriptor.loader.java/src/META-INF/services/org.jetbrains.kotlin.resolve.ExternalOverridabilityCondition

@@ -1 +1,2 @@
-org.jetbrains.kotlin.load.java.FieldOverridabilityCondition
+org.jetbrains.kotlin.load.java.FieldOverridabilityCondition
+org.jetbrains.kotlin.load.java.ErasedOverridabilityCondition

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/ErasedOverridabilityCondition.kt

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2010-2015 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.
+ */
+
+package org.jetbrains.kotlin.load.java
+
+import org.jetbrains.kotlin.descriptors.CallableDescriptor
+import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
+import org.jetbrains.kotlin.load.java.descriptors.JavaMethodDescriptor
+import org.jetbrains.kotlin.load.java.lazy.types.RawSubstitution
+import org.jetbrains.kotlin.resolve.ExternalOverridabilityCondition
+import org.jetbrains.kotlin.resolve.ExternalOverridabilityCondition.Result
+import org.jetbrains.kotlin.resolve.OverridingUtil
+
+class ErasedOverridabilityCondition : ExternalOverridabilityCondition {
+    override fun isOverridable(superDescriptor: CallableDescriptor, subDescriptor: CallableDescriptor): Result {
+        if (subDescriptor !is JavaMethodDescriptor) return Result.UNKNOWN
+
+        var erasedSuper = superDescriptor.substitute(RawSubstitution.buildSubstitutor()) ?: return Result.UNKNOWN
+
+        if (erasedSuper is SimpleFunctionDescriptor && erasedSuper.typeParameters.isNotEmpty()) {
+            // Only simple functions are supported now for erased overrides
+            erasedSuper = erasedSuper.createCopyWithNewTypeParameters(emptyList())
+        }
+
+        val overridabilityResult =
+                OverridingUtil.DEFAULT.isOverridableByWithoutExternalConditions(erasedSuper, subDescriptor, false).result
+        return when (overridabilityResult) {
+            OverridingUtil.OverrideCompatibilityInfo.Result.OVERRIDABLE -> Result.OVERRIDABLE
+            else ->  Result.UNKNOWN
+        }
+    }
+}