diff --git a/core/descriptors/src/org/jetbrains/kotlin/descriptors/TypeAliasDescriptor.kt b/core/descriptors/src/org/jetbrains/kotlin/descriptors/TypeAliasDescriptor.kt
index 6f5254fb363..076126c5e36 100644
--- a/core/descriptors/src/org/jetbrains/kotlin/descriptors/TypeAliasDescriptor.kt
+++ b/core/descriptors/src/org/jetbrains/kotlin/descriptors/TypeAliasDescriptor.kt
@@ -30,5 +30,7 @@ interface TypeAliasDescriptor : ClassifierDescriptorWithTypeParameters {
 
     val classDescriptor: ClassDescriptor?
 
+    override fun getOriginal(): TypeAliasDescriptor
+
     override fun substitute(substitutor: TypeSubstitutor): TypeAliasDescriptor
 }
diff --git a/core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/AbstractTypeAliasDescriptor.kt b/core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/AbstractTypeAliasDescriptor.kt
index 072b8c7a4f5..f84841fbb8e 100644
--- a/core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/AbstractTypeAliasDescriptor.kt
+++ b/core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/AbstractTypeAliasDescriptor.kt
@@ -76,6 +76,8 @@ abstract class AbstractTypeAliasDescriptor(
 
     override fun toString(): String = "typealias ${name.asString()}"
 
+    override fun getOriginal(): TypeAliasDescriptor = super.getOriginal() as TypeAliasDescriptor
+
     protected abstract fun getTypeConstructorTypeParameters(): List<TypeParameterDescriptor>
 
     protected fun computeDefaultType(): SimpleType =