Extension point for synthetic function names contributions

compiler/frontend/src/org/jetbrains/kotlin/resolve/extensions/SyntheticResolveExtension.kt

@@ -42,6 +42,9 @@ interface SyntheticResolveExtension {
                 override fun getSyntheticNestedClassNames(thisDescriptor: ClassDescriptor): List<Name> =
                         instances.flatMap { it.getSyntheticNestedClassNames(thisDescriptor) }
 
+                override fun getSyntheticFunctionNames(thisDescriptor: ClassDescriptor): List<Name> =
+                        instances.flatMap { it.getSyntheticFunctionNames(thisDescriptor) }
+
                 override fun generateSyntheticClasses(thisDescriptor: ClassDescriptor, name: Name,
                                                       ctx: LazyClassContext, declarationProvider: ClassMemberDeclarationProvider,
                                                       result: MutableSet<ClassDescriptor>) =
@@ -69,6 +72,8 @@ interface SyntheticResolveExtension {
 
     fun getSyntheticCompanionObjectNameIfNeeded(thisDescriptor: ClassDescriptor): Name? = null
 
+    fun getSyntheticFunctionNames(thisDescriptor: ClassDescriptor): List<Name> = emptyList()
+
     fun getSyntheticNestedClassNames(thisDescriptor: ClassDescriptor): List<Name> = emptyList()
 
     fun addSyntheticSupertypes(thisDescriptor: ClassDescriptor, supertypes: MutableList<KotlinType>) {}

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/descriptors/LazyClassMemberScope.kt

@@ -80,6 +80,7 @@ open class LazyClassMemberScope(
         }
 
         addDataClassMethods(result, location)
+        addSyntheticFunctions(result, location)
         addSyntheticCompanionObject(result, location)
         addSyntheticNestedClasses(result, location)
 
@@ -220,6 +221,10 @@ open class LazyClassMemberScope(
         result.add(descriptor)
     }
 
+    private fun addSyntheticFunctions(result: MutableCollection<DeclarationDescriptor>, location: LookupLocation) {
+        result.addAll(c.syntheticResolveExtension.getSyntheticFunctionNames(thisDescriptor).flatMap { getContributedFunctions(it, location) }.toList())
+    }
+
     private fun addSyntheticNestedClasses(result: MutableCollection<DeclarationDescriptor>, location: LookupLocation) {
         result.addAll(c.syntheticResolveExtension.getSyntheticNestedClassNames(thisDescriptor).mapNotNull { getContributedClassifier(it, location) }.toList())
     }