[ASTImporter] Error handling fix in ImportDefinition_New.

[balazske]

Summary

ASTImporter::ImportDefinition_New contained a call to Import
that should be Import_New now. This is fixed now.

[balazske]

• Removed unneeded and wrong type cast.

[balazske]

Rebase to current master.

[balazske]

ping

[balazske]

The error handling is already done in other way, but the current code does crash if called with non-DeclContext From argument. This may be possible from LLDB so it is better to have this change.

[balazske]

This change is obsolete in the current code. Casting related changes do not look important (and should be a new patch anyway).

lib/AST/ASTImporter.cpp

CXXBaseSpecifier *ASTImporter::Import(const CXXBaseSpecifier *From) {
   if (To)
     return *To;
   else
     llvm::consumeError(To.takeError());
   return nullptr;
 }
 
 Error ASTImporter::ImportDefinition_New(Decl *From) {
-  Decl *To = Import(From);
-  if (!To)
-    return llvm::make_error<ImportError>();
+  Decl *To;
+  if (Error Err = importInto(To, From))
+    return Err;
 
-  auto *FromDC = cast<DeclContext>(From);
+  if (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,
             ASTNodeImporter::IDK_Everything);
       }
     }
 
     if (auto *ToEnum = dyn_cast<EnumDecl>(To)) {
       if (!ToEnum->getDefinition()) {
         return Importer.ImportDefinition(
             cast<EnumDecl>(FromDC), ToEnum, ASTNodeImporter::IDK_Everything);
       }
     }
 
     if (auto *ToIFace = dyn_cast<ObjCInterfaceDecl>(To)) {
       if (!ToIFace->getDefinition()) {
         return Importer.ImportDefinition(
             cast<ObjCInterfaceDecl>(FromDC), ToIFace,
             ASTNodeImporter::IDK_Everything);
       }
     }
 
     if (auto *ToProto = dyn_cast<ObjCProtocolDecl>(To)) {
       if (!ToProto->getDefinition()) {
         return Importer.ImportDefinition(
             cast<ObjCProtocolDecl>(FromDC), ToProto,
             ASTNodeImporter::IDK_Everything);
       }
     }
 
     return Importer.ImportDeclContext(FromDC, true);
   }
 
+  return Error::success();
+}
+
 void ASTImporter::ImportDefinition(Decl *From) {
   Error Err = ImportDefinition_New(From);
   llvm::consumeError(std::move(Err));
 }
 
 Expected<DeclarationName> ASTImporter::Import_New(DeclarationName FromName) {
   if (!FromName)
     return DeclarationName{};