PR9023: A template template parameter whose template parameter list contains an

unexpanded parameter pack is a pack expansion. Thus, as with a non-type template
parameter which is a pack expansion, it needs to be expanded early into a fixed
list of template parameters.

Since the expanded list of template parameters is not itself a parameter pack,
it is permitted to appear before the end of the template parameter list, so also
remove that restriction (for both template template parameter pack expansions and
non-type template parameter pack expansions).

llvm-svn: 163369

1 files changed, 16 insertions, 5 deletions

diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 2418f3a1674..ba830d172cc 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -1486,11 +1486,18 @@ void ASTDeclReader::VisitTemplateTemplateParmDecl(TemplateTemplateParmDecl *D) {
   // TemplateParmPosition.
   D->setDepth(Record[Idx++]);
   D->setPosition(Record[Idx++]);
-  // Rest of TemplateTemplateParmDecl.
-  TemplateArgumentLoc Arg = Reader.ReadTemplateArgumentLoc(F, Record, Idx);
-  bool IsInherited = Record[Idx++];
-  D->setDefaultArgument(Arg, IsInherited);
-  D->ParameterPack = Record[Idx++];
+  if (D->isExpandedParameterPack()) {
+    void **Data = reinterpret_cast<void **>(D + 1);
+    for (unsigned I = 0, N = D->getNumExpansionTemplateParameters();
+         I != N; ++I)
+      Data[I] = Reader.ReadTemplateParameterList(F, Record, Idx);
+  } else {
+    // Rest of TemplateTemplateParmDecl.
+    TemplateArgumentLoc Arg = Reader.ReadTemplateArgumentLoc(F, Record, Idx);
+    bool IsInherited = Record[Idx++];
+    D->setDefaultArgument(Arg, IsInherited);
+    D->ParameterPack = Record[Idx++];
+  }
 }
 
 void ASTDeclReader::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {
@@ -2004,6 +2011,10 @@ Decl *ASTReader::ReadDeclRecord(DeclID ID) {
   case DECL_TEMPLATE_TEMPLATE_PARM:
     D = TemplateTemplateParmDecl::CreateDeserialized(Context, ID);
     break;
+  case DECL_EXPANDED_TEMPLATE_TEMPLATE_PARM_PACK:
+    D = TemplateTemplateParmDecl::CreateDeserialized(Context, ID,
+                                                     Record[Idx++]);
+    break;
   case DECL_TYPE_ALIAS_TEMPLATE:
     D = TypeAliasTemplateDecl::CreateDeserialized(Context, ID);
     break;