Make sure to put template parameters into their owning template's

DeclContext once we've created it. This mirrors what we do for
function parameters, where the parameters start out with
translation-unit context and then are adopted by the appropriate
DeclContext when it is created. Also give template parameters public
access and make sure that they don't show up for the purposes of name
lookup.

Fixes PR9400, a regression introduced by r126920, which implemented
substitution of default template arguments provided in template
template parameters (C++ core issue 150).

How on earth could the DeclContext of a template parameter affect the
handling of default template arguments?

I'm so glad you asked! The link is
Sema::getTemplateInstantiationArgs(), which determines the outer
template argument lists that correspond to a given declaration. When
we're instantiating a default template argument for a template
template parameter within the body of a template definition (not it's
instantiation, per core issue 150), we weren't getting any outer
template arguments because the context of the template template
parameter was the translation unit. Now that the context of the
template template parameter is its owning template, we get the
template arguments from the injected-class-name of the owning
template, so substitution works as it should.

llvm-svn: 127004

1 files changed, 47 insertions, 0 deletions

diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index 0554cfca3a6..266d913ff4b 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -165,9 +165,20 @@ FunctionTemplateDecl *FunctionTemplateDecl::Create(ASTContext &C,
                                                    DeclarationName Name,
                                                TemplateParameterList *Params,
                                                    NamedDecl *Decl) {
+  // Take ownership of the template parameters.
+  for (TemplateParameterList::iterator P = Params->begin(), 
+                                    PEnd = Params->end();
+       P != PEnd; ++P)
+    (*P)->setDeclContext(cast<DeclContext>(Decl));
+
   return new (C) FunctionTemplateDecl(DC, L, Name, Params, Decl);
 }
 
+FunctionTemplateDecl *FunctionTemplateDecl::Create(ASTContext &C, EmptyShell) {
+  return new (C) FunctionTemplateDecl(0, SourceLocation(), DeclarationName(),
+                                      0, 0);
+}
+
 RedeclarableTemplateDecl::CommonBase *
 FunctionTemplateDecl::newCommon(ASTContext &C) {
   Common *CommonPtr = new (C) Common;
@@ -196,11 +207,21 @@ ClassTemplateDecl *ClassTemplateDecl::Create(ASTContext &C,
                                              TemplateParameterList *Params,
                                              NamedDecl *Decl,
                                              ClassTemplateDecl *PrevDecl) {
+  // Take ownership of the template parameters.
+  for (TemplateParameterList::iterator P = Params->begin(), 
+                                    PEnd = Params->end();
+       P != PEnd; ++P)
+    (*P)->setDeclContext(cast<DeclContext>(Decl));
+  
   ClassTemplateDecl *New = new (C) ClassTemplateDecl(DC, L, Name, Params, Decl);
   New->setPreviousDeclaration(PrevDecl);
   return New;
 }
 
+ClassTemplateDecl *ClassTemplateDecl::Create(ASTContext &C, EmptyShell Empty) {
+  return new (C) ClassTemplateDecl(Empty);
+}
+
 void ClassTemplateDecl::LoadLazySpecializations() {
   Common *CommonPtr = getCommonPtr();
   if (CommonPtr->LazySpecializations) {
@@ -593,6 +614,32 @@ ClassTemplateSpecializationDecl::getSourceRange() const {
 //===----------------------------------------------------------------------===//
 // ClassTemplatePartialSpecializationDecl Implementation
 //===----------------------------------------------------------------------===//
+ClassTemplatePartialSpecializationDecl::
+ClassTemplatePartialSpecializationDecl(ASTContext &Context, TagKind TK,
+                                       DeclContext *DC, SourceLocation L,
+                                       TemplateParameterList *Params,
+                                       ClassTemplateDecl *SpecializedTemplate,
+                                       const TemplateArgument *Args,
+                                       unsigned NumArgs,
+                                       TemplateArgumentLoc *ArgInfos,
+                                       unsigned NumArgInfos,
+                               ClassTemplatePartialSpecializationDecl *PrevDecl,
+                                       unsigned SequenceNumber)
+  : ClassTemplateSpecializationDecl(Context,
+                                    ClassTemplatePartialSpecialization,
+                                    TK, DC, L, SpecializedTemplate, 
+                                    Args, NumArgs, PrevDecl),
+    TemplateParams(Params), ArgsAsWritten(ArgInfos),
+    NumArgsAsWritten(NumArgInfos), SequenceNumber(SequenceNumber),
+    InstantiatedFromMember(0, false)
+{ 
+  // Take ownership of the template parameters.
+  for (TemplateParameterList::iterator P = Params->begin(), 
+                                    PEnd = Params->end();
+       P != PEnd; ++P)
+    (*P)->setDeclContext(this);
+}
+
 ClassTemplatePartialSpecializationDecl *
 ClassTemplatePartialSpecializationDecl::
 Create(ASTContext &Context, TagKind TK,DeclContext *DC, SourceLocation L,