Fix for https://youtrack.jetbrains.com/issue/KT-25427

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

@@ -124,7 +124,7 @@ private fun acyclicTypeMangler(visited: MutableSet<TypeParameterDescriptor>, typ
                 if (bound == "kotlin.Any?") "" else "_$bound"
             }.joinToString("")
         }
-        return "#GENERIC" + upperBounds
+        return "#GENERIC${if (type.isMarkedNullable()) "?" else ""}$upperBounds"
     }
 
     var hashString = type.getClass()!!.fqNameSafe.asString()