AST: Remove ArchetypeType::getParent()

Author: slavapestov

include/swift/AST/Types.h

@@ -6574,10 +6574,6 @@ class ArchetypeType : public SubstitutableType,
   /// which the archetype conforms.
   Type getNestedTypeByName(Identifier name);
 
-  /// Retrieve the parent of this archetype, or null if this is a
-  /// primary archetype.
-  ArchetypeType *getParent() const;
-
   /// Return the archetype that represents the root generic parameter of its
   /// interface type.
   ArchetypeType *getRoot() const;

lib/AST/Type.cpp

@@ -3381,15 +3381,6 @@ ArchetypeType::ArchetypeType(TypeKind Kind,
                           getSubclassTrailingObjects<ProtocolDecl *>());
 }
 
-ArchetypeType *ArchetypeType::getParent() const {
-  if (auto depMemTy = getInterfaceType()->getAs<DependentMemberType>()) {
-    return getGenericEnvironment()->mapTypeIntoContext(depMemTy->getBase())
-        ->castTo<ArchetypeType>();
-  }
-
-  return nullptr;
-}
-
 ArchetypeType *ArchetypeType::getRoot() const {
   if (isRoot()) {
     return const_cast<ArchetypeType *>(this);