When we use the default template arguments of a template template
parameter, save the instantiated default template arguments along with
the explicitly-specified template argument list. That way, we prefer
the default template template arguments corresponding to the template
template parameter rather than those of its template template argument.

This addresses the likely direction of C++ core issue 150, and fixes
PR9353/<rdar://problem/9069136>, bringing us closer to the behavior of
EDG and GCC.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126920 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index abfb7bd..579da8b 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -1210,7 +1210,7 @@
   void AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl,
                                   DeclAccessPair FoundDecl,
                                   CXXRecordDecl *ActingContext,
-                         const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
                                   QualType ObjectType,
                                   Expr::Classification ObjectClassification,
                                   Expr **Args, unsigned NumArgs,
@@ -1218,7 +1218,7 @@
                                   bool SuppressUserConversions = false);
   void AddTemplateOverloadCandidate(FunctionTemplateDecl *FunctionTemplate,
                                     DeclAccessPair FoundDecl,
-                      const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
                                     Expr **Args, unsigned NumArgs,
                                     OverloadCandidateSet& CandidateSet,
                                     bool SuppressUserConversions = false);
@@ -1255,7 +1255,7 @@
   void AddArgumentDependentLookupCandidates(DeclarationName Name,
                                             bool Operator,
                                             Expr **Args, unsigned NumArgs,
-                        const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                                TemplateArgumentListInfo *ExplicitTemplateArgs,
                                             OverloadCandidateSet& CandidateSet,
                                             bool PartialOverloading = false);
 
@@ -3180,7 +3180,7 @@
 
   QualType CheckTemplateIdType(TemplateName Template,
                                SourceLocation TemplateLoc,
-                               const TemplateArgumentListInfo &TemplateArgs);
+                              TemplateArgumentListInfo &TemplateArgs);
 
   TypeResult
   ActOnTemplateIdType(CXXScopeSpec &SS,
@@ -3253,7 +3253,7 @@
                                                     LookupResult &Previous);
 
   bool CheckFunctionTemplateSpecialization(FunctionDecl *FD,
-                        const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                         TemplateArgumentListInfo *ExplicitTemplateArgs,
                                            LookupResult &Previous);
   bool CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous);
 
@@ -3319,9 +3319,30 @@
                            llvm::SmallVectorImpl<TemplateArgument> &Converted,
                              CheckTemplateArgumentKind CTAK = CTAK_Specified);
 
+  /// \brief Check that the given template arguments can be be provided to
+  /// the given template, converting the arguments along the way.
+  ///
+  /// \param Template The template to which the template arguments are being
+  /// provided.
+  ///
+  /// \param TemplateLoc The location of the template name in the source.
+  ///
+  /// \param TemplateArgs The list of template arguments. If the template is
+  /// a template template parameter, this function may extend the set of
+  /// template arguments to also include substituted, defaulted template
+  /// arguments.
+  ///
+  /// \param PartialTemplateArgs True if the list of template arguments is
+  /// intentionally partial, e.g., because we're checking just the initial
+  /// set of template arguments.
+  ///
+  /// \param Converted Will receive the converted, canonicalized template
+  /// arguments.
+  ///
+  /// \returns True if an error occurred, false otherwise.
   bool CheckTemplateArgumentList(TemplateDecl *Template,
                                  SourceLocation TemplateLoc,
-                                 const TemplateArgumentListInfo &TemplateArgs,
+                                 TemplateArgumentListInfo &TemplateArgs,
                                  bool PartialTemplateArgs,
                            llvm::SmallVectorImpl<TemplateArgument> &Converted);
 
@@ -3787,7 +3808,7 @@
 
   TemplateDeductionResult
   SubstituteExplicitTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
-                        const TemplateArgumentListInfo &ExplicitTemplateArgs,
+                              TemplateArgumentListInfo &ExplicitTemplateArgs,
                       llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced,
                                  llvm::SmallVectorImpl<QualType> &ParamTypes,
                                       QualType *FunctionType,
@@ -3802,14 +3823,14 @@
 
   TemplateDeductionResult
   DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
-                          const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                          TemplateArgumentListInfo *ExplicitTemplateArgs,
                           Expr **Args, unsigned NumArgs,
                           FunctionDecl *&Specialization,
                           sema::TemplateDeductionInfo &Info);
 
   TemplateDeductionResult
   DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
-                          const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                          TemplateArgumentListInfo *ExplicitTemplateArgs,
                           QualType ArgFunctionType,
                           FunctionDecl *&Specialization,
                           sema::TemplateDeductionInfo &Info);
@@ -3822,7 +3843,7 @@
 
   TemplateDeductionResult
   DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
-                          const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                          TemplateArgumentListInfo *ExplicitTemplateArgs,
                           FunctionDecl *&Specialization,
                           sema::TemplateDeductionInfo &Info);
 
diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp
index 14d545d..bf24b74 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -4061,7 +4061,7 @@
 Sema::AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl,
                                  DeclAccessPair FoundDecl,
                                  CXXRecordDecl *ActingContext,
-                        const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
                                  QualType ObjectType,
                                  Expr::Classification ObjectClassification,
                                  Expr **Args, unsigned NumArgs,
@@ -4114,7 +4114,7 @@
 void
 Sema::AddTemplateOverloadCandidate(FunctionTemplateDecl *FunctionTemplate,
                                    DeclAccessPair FoundDecl,
-                        const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
                                    Expr **Args, unsigned NumArgs,
                                    OverloadCandidateSet& CandidateSet,
                                    bool SuppressUserConversions) {
@@ -6090,7 +6090,7 @@
 Sema::AddArgumentDependentLookupCandidates(DeclarationName Name,
                                            bool Operator,
                                            Expr **Args, unsigned NumArgs,
-                       const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
                                            OverloadCandidateSet& CandidateSet,
                                            bool PartialOverloading) {
   ADLResult Fns;
@@ -7493,7 +7493,7 @@
 /// \brief Add a single candidate to the overload set.
 static void AddOverloadedCallCandidate(Sema &S,
                                        DeclAccessPair FoundDecl,
-                       const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
                                        Expr **Args, unsigned NumArgs,
                                        OverloadCandidateSet &CandidateSet,
                                        bool PartialOverloading) {
@@ -7559,7 +7559,7 @@
 
   // It would be nice to avoid this copy.
   TemplateArgumentListInfo TABuffer;
-  const TemplateArgumentListInfo *ExplicitTemplateArgs = 0;
+  TemplateArgumentListInfo *ExplicitTemplateArgs = 0;
   if (ULE->hasExplicitTemplateArgs()) {
     ULE->copyTemplateArgumentsInto(TABuffer);
     ExplicitTemplateArgs = &TABuffer;
diff --git a/lib/Sema/SemaTemplate.cpp b/lib/Sema/SemaTemplate.cpp
index 49f9a1d..53d1a9e 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -1631,7 +1631,7 @@
 
 QualType Sema::CheckTemplateIdType(TemplateName Name,
                                    SourceLocation TemplateLoc,
-                              const TemplateArgumentListInfo &TemplateArgs) {
+                                   TemplateArgumentListInfo &TemplateArgs) {
   TemplateDecl *Template = Name.getAsTemplateDecl();
   if (!Template) {
     // The template name does not resolve to a template, so we just
@@ -2535,7 +2535,7 @@
 /// for specializing the given template.
 bool Sema::CheckTemplateArgumentList(TemplateDecl *Template,
                                      SourceLocation TemplateLoc,
-                                const TemplateArgumentListInfo &TemplateArgs,
+                                     TemplateArgumentListInfo &TemplateArgs,
                                      bool PartialTemplateArgs,
                           llvm::SmallVectorImpl<TemplateArgument> &Converted) {
   TemplateParameterList *Params = Template->getTemplateParameters();
@@ -2573,6 +2573,7 @@
   //   a template-id shall match the type and form specified for the
   //   corresponding parameter declared by the template in its
   //   template-parameter-list.
+  bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
   llvm::SmallVector<TemplateArgument, 2> ArgumentPack;
   TemplateParameterList::iterator Param = Params->begin(),
                                ParamEnd = Params->end();
@@ -2703,6 +2704,12 @@
                               RAngleLoc, 0, Converted))
       return true;
 
+    // Core issue 150 (assumed resolution): if this is a template template 
+    // parameter, keep track of the default template arguments from the 
+    // template definition.
+    if (isTemplateTemplateParameter)
+      TemplateArgs.addArgument(Arg);
+    
     // Move to the next template parameter and argument.
     ++Param;
     ++ArgIdx;
@@ -5002,7 +5009,7 @@
 /// this function specialization.
 bool
 Sema::CheckFunctionTemplateSpecialization(FunctionDecl *FD,
-                        const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
                                           LookupResult &Previous) {
   // The set of function template specializations that could match this
   // explicit function template specialization.
diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index c3d4362..43cbd62 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -2009,7 +2009,7 @@
 Sema::TemplateDeductionResult
 Sema::SubstituteExplicitTemplateArguments(
                                       FunctionTemplateDecl *FunctionTemplate,
-                        const TemplateArgumentListInfo &ExplicitTemplateArgs,
+                               TemplateArgumentListInfo &ExplicitTemplateArgs,
                        llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced,
                                  llvm::SmallVectorImpl<QualType> &ParamTypes,
                                           QualType *FunctionType,
@@ -2576,7 +2576,7 @@
 /// \returns the result of template argument deduction.
 Sema::TemplateDeductionResult
 Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
-                          const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                              TemplateArgumentListInfo *ExplicitTemplateArgs,
                               Expr **Args, unsigned NumArgs,
                               FunctionDecl *&Specialization,
                               TemplateDeductionInfo &Info) {
@@ -2774,7 +2774,7 @@
 /// \returns the result of template argument deduction.
 Sema::TemplateDeductionResult
 Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
-                        const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                              TemplateArgumentListInfo *ExplicitTemplateArgs,
                               QualType ArgFunctionType,
                               FunctionDecl *&Specialization,
                               TemplateDeductionInfo &Info) {
@@ -2954,7 +2954,7 @@
 /// \returns the result of template argument deduction.
 Sema::TemplateDeductionResult
 Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
-                           const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                              TemplateArgumentListInfo *ExplicitTemplateArgs,
                               FunctionDecl *&Specialization,
                               TemplateDeductionInfo &Info) {
   return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs,
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 866d341..76792a0 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -713,7 +713,7 @@
   /// different behavior.
   QualType RebuildTemplateSpecializationType(TemplateName Template,
                                              SourceLocation TemplateLoc,
-                                       const TemplateArgumentListInfo &Args);
+                                             TemplateArgumentListInfo &Args);
 
   /// \brief Build a new parenthesized type.
   ///
@@ -747,7 +747,7 @@
                                           NestedNameSpecifierLoc QualifierLoc,
                                           const IdentifierInfo *Name,
                                           SourceLocation NameLoc,
-                                        const TemplateArgumentListInfo &Args) {
+                                          TemplateArgumentListInfo &Args) {
     // Rebuild the template name.
     // TODO: avoid TemplateName abstraction
     CXXScopeSpec SS;
@@ -7644,7 +7644,7 @@
 QualType TreeTransform<Derived>::RebuildTemplateSpecializationType(
                                                       TemplateName Template,
                                              SourceLocation TemplateNameLoc,
-                               const TemplateArgumentListInfo &TemplateArgs) {
+                                     TemplateArgumentListInfo &TemplateArgs) {
   return SemaRef.CheckTemplateIdType(Template, TemplateNameLoc, TemplateArgs);
 }
 
diff --git a/test/SemaTemplate/issue150.cpp b/test/SemaTemplate/issue150.cpp
new file mode 100644
index 0000000..647df2c
--- /dev/null
+++ b/test/SemaTemplate/issue150.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+// Core issue 150: Template template parameters and default arguments
+
+namespace PR9353 {
+  template<class _T, class Traits> class IM;
+
+  template <class T, class Trt, 
+            template<class _T, class Traits = int> class IntervalMap>
+  void foo(IntervalMap<T,Trt>* m) { typedef IntervalMap<int> type; }
+
+  void f(IM<int, int>* m) { foo(m); }
+}