Index: lib/AST/ASTImporter.cpp
===================================================================
--- lib/AST/ASTImporter.cpp
+++ lib/AST/ASTImporter.cpp
@@ -8358,18 +8358,16 @@
 }
 
 Error ASTImporter::ImportDefinition(Decl *From) {
-  ExpectedDecl ToOrErr = Import(From);
-  if (!ToOrErr)
-    return ToOrErr.takeError();
-  Decl *To = *ToOrErr;
+  Decl *To;
+  if (Error Err = importInto(To, From))
+    return Err;
 
-  auto *FromDC = cast<DeclContext>(From);
   ASTNodeImporter Importer(*this);
 
   if (auto *ToRecord = dyn_cast<RecordDecl>(To)) {
     if (!ToRecord->getDefinition()) {
       return Importer.ImportDefinition(
-          cast<RecordDecl>(FromDC), ToRecord,
+          cast<RecordDecl>(From), ToRecord,
           ASTNodeImporter::IDK_Everything);
     }
   }
@@ -8377,14 +8375,14 @@
   if (auto *ToEnum = dyn_cast<EnumDecl>(To)) {
     if (!ToEnum->getDefinition()) {
       return Importer.ImportDefinition(
-          cast<EnumDecl>(FromDC), ToEnum, ASTNodeImporter::IDK_Everything);
+          cast<EnumDecl>(From), ToEnum, ASTNodeImporter::IDK_Everything);
     }
   }
 
   if (auto *ToIFace = dyn_cast<ObjCInterfaceDecl>(To)) {
     if (!ToIFace->getDefinition()) {
       return Importer.ImportDefinition(
-          cast<ObjCInterfaceDecl>(FromDC), ToIFace,
+          cast<ObjCInterfaceDecl>(From), ToIFace,
           ASTNodeImporter::IDK_Everything);
     }
   }
@@ -8392,12 +8390,15 @@
   if (auto *ToProto = dyn_cast<ObjCProtocolDecl>(To)) {
     if (!ToProto->getDefinition()) {
       return Importer.ImportDefinition(
-          cast<ObjCProtocolDecl>(FromDC), ToProto,
+          cast<ObjCProtocolDecl>(From), ToProto,
           ASTNodeImporter::IDK_Everything);
     }
   }
 
-  return Importer.ImportDeclContext(FromDC, true);
+  if (auto *FromDC = dyn_cast<DeclContext>(From))
+    return Importer.ImportDeclContext(FromDC, true);
+
+  return Error::success();
 }
 
 Expected<DeclarationName> ASTImporter::Import(DeclarationName FromName) {