[modules] Track the described template in an alias declaration that is the

pattern of an alias template declaration. Use this to merge alias templates
properly when they're members of class template specializations.

llvm-svn: 216437

1 files changed, 12 insertions, 5 deletions

diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 2503500dcd4..5f7a93f1320 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -234,7 +234,7 @@ namespace clang {
     void VisitUsingDirectiveDecl(UsingDirectiveDecl *D);
     void VisitNamespaceAliasDecl(NamespaceAliasDecl *D);
     void VisitTypeDecl(TypeDecl *TD);
-    void VisitTypedefNameDecl(TypedefNameDecl *TD);
+    RedeclarableResult VisitTypedefNameDecl(TypedefNameDecl *TD);
     void VisitTypedefDecl(TypedefDecl *TD);
     void VisitTypeAliasDecl(TypeAliasDecl *TD);
     void VisitUnresolvedUsingTypenameDecl(UnresolvedUsingTypenameDecl *D);
@@ -456,7 +456,8 @@ void ASTDeclReader::VisitTypeDecl(TypeDecl *TD) {
   TypeIDForTypeDecl = Reader.getGlobalTypeID(F, Record[Idx++]);
 }
 
-void ASTDeclReader::VisitTypedefNameDecl(TypedefNameDecl *TD) {
+ASTDeclReader::RedeclarableResult
+ASTDeclReader::VisitTypedefNameDecl(TypedefNameDecl *TD) {
   RedeclarableResult Redecl = VisitRedeclarable(TD);
   VisitTypeDecl(TD);
   TypeSourceInfo *TInfo = GetTypeSourceInfo(Record, Idx);
@@ -465,15 +466,21 @@ void ASTDeclReader::VisitTypedefNameDecl(TypedefNameDecl *TD) {
     TD->setModedTypeSourceInfo(TInfo, modedT);
   } else
     TD->setTypeSourceInfo(TInfo);
-  mergeRedeclarable(TD, Redecl);
+  return Redecl;
 }
 
 void ASTDeclReader::VisitTypedefDecl(TypedefDecl *TD) {
-  VisitTypedefNameDecl(TD);
+  RedeclarableResult Redecl = VisitTypedefNameDecl(TD);
+  mergeRedeclarable(TD, Redecl);
 }
 
 void ASTDeclReader::VisitTypeAliasDecl(TypeAliasDecl *TD) {
-  VisitTypedefNameDecl(TD);
+  RedeclarableResult Redecl = VisitTypedefNameDecl(TD);
+  if (auto *Template = ReadDeclAs<TypeAliasTemplateDecl>(Record, Idx))
+    // Merged when we merge the template.
+    TD->setDescribedAliasTemplate(Template);
+  else
+    mergeRedeclarable(TD, Redecl);
 }
 
 ASTDeclReader::RedeclarableResult ASTDeclReader::VisitTagDecl(TagDecl *TD) {