Fix override conflicts with different return types

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/BinaryInterface.kt

@@ -160,7 +160,7 @@ private val FunctionDescriptor.signature: String
                 when {
                     this.typeParameters.isNotEmpty() -> "Generic"
                     returnType.let { it != null && it.isValueType() } -> "ValueType"
-                    returnType.let { it != null && !KotlinBuiltIns.isUnitOrNullableUnit(it) } -> "Reference"
+                    returnType.let { it != null && !KotlinBuiltIns.isUnitOrNullableUnit(it) } -> typeToHashString(returnType!!)
                     else -> ""
                 }
 

backend.native/tests/build.gradle

@@ -907,6 +907,10 @@ task bridges_special(type: RunKonanTest) {
     source = "codegen/bridges/special.kt"
 }
 
+task returnTypeSignature(type: RunKonanTest) {
+    source = "codegen/bridges/returnTypeSignature.kt"
+}
+
 task classDelegation_method(type: RunKonanTest) {
     goldValue = "OKOK\n"
     source = "codegen/classDelegation/method.kt"

backend.native/tests/codegen/bridges/returnTypeSignature.kt

@@ -0,0 +1,29 @@
+package codegen.bridges.signature
+
+import kotlin.test.*
+
+class A { }
+
+class B { }
+
+class C { }
+
+interface Parser<in IN: Any, out OUT: Any> {
+    fun parse(source: IN): OUT
+}
+
+interface MultiParser<in IN: Any, out OUT: Any> {
+    fun parse(source: IN): Collection<OUT>
+}
+
+interface ExtendsInterface<T: Any>: Parser<A, T>, MultiParser<B, T> {
+    override fun parse(source: B): Collection<T> = ArrayList<T>()
+}
+
+abstract class AbstractClass(): ExtendsInterface<C> {
+    public override fun parse(source: A): C = C()
+}
+
+@Test fun runTest() {
+    val array = object : AbstractClass() { }.parse(B())
+}