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

6 files changed, 66 insertions, 25 deletions

diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index abfb7bd38f..579da8b177 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -1210,7 +1210,7 @@ public:
   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 @@ public:
                                   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 @@ public:
   void AddArgumentDependentLookupCandidates(DeclarationName Name,
                                             bool Operator,
                                             Expr **Args, unsigned NumArgs,
-                        const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                                TemplateArgumentListInfo *ExplicitTemplateArgs,
                                             OverloadCandidateSet& CandidateSet,
                                             bool PartialOverloading = false);
 
@@ -3180,7 +3180,7 @@ public:
 
   QualType CheckTemplateIdType(TemplateName Template,
                                SourceLocation TemplateLoc,
-                               const TemplateArgumentListInfo &TemplateArgs);
+                              TemplateArgumentListInfo &TemplateArgs);
 
   TypeResult
   ActOnTemplateIdType(CXXScopeSpec &SS,
@@ -3253,7 +3253,7 @@ public:
                                                     LookupResult &Previous);
 
   bool CheckFunctionTemplateSpecialization(FunctionDecl *FD,
-                        const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                         TemplateArgumentListInfo *ExplicitTemplateArgs,
                                            LookupResult &Previous);
   bool CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous);
 
@@ -3319,9 +3319,30 @@ public:
                            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 @@ public:
 
   TemplateDeductionResult
   SubstituteExplicitTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
-                        const TemplateArgumentListInfo &ExplicitTemplateArgs,
+                              TemplateArgumentListInfo &ExplicitTemplateArgs,
                       llvm::SmallVectorImpl<DeducedTemplateArgument> &Deduced,
                                  llvm::SmallVectorImpl<QualType> &ParamTypes,
                                       QualType *FunctionType,
@@ -3802,14 +3823,14 @@ public:
 
   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 @@ public:
 
   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 14d545d3e4..bf24b74848 100644
--- a/lib/Sema/SemaOverload.cpp
+++ b/lib/Sema/SemaOverload.cpp
@@ -4061,7 +4061,7 @@ void
 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 @@ Sema::AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl,
 void
 Sema::AddTemplateOverloadCandidate(FunctionTemplateDecl *FunctionTemplate,
                                    DeclAccessPair FoundDecl,
-                        const TemplateArgumentListInfo *ExplicitTemplateArgs,
+                                 TemplateArgumentListInfo *ExplicitTemplateArgs,
                                    Expr **Args, unsigned NumArgs,
                                    OverloadCandidateSet& CandidateSet,
                                    bool SuppressUserConversions) {
@@ -6090,7 +6090,7 @@ void
 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 @@ FunctionDecl *Sema::ResolveSingleFunctionTemplateSpecialization(Expr *From,
 /// \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 @@ void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
 
   // 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 49f9a1de1e..53d1a9e430 100644
--- a/lib/Sema/SemaTemplate.cpp
+++ b/lib/Sema/SemaTemplate.cpp
@@ -1631,7 +1631,7 @@ Sema::MatchTemplateParametersToScopeSpecifier(SourceLocation DeclStartLoc,
 
 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 @@ bool Sema::CheckTemplateArgument(NamedDecl *Param,
 /// 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 @@ bool Sema::CheckTemplateArgumentList(TemplateDecl *Template,
   //   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 @@ bool Sema::CheckTemplateArgumentList(TemplateDecl *Template,
                               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 @@ Sema::CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
 /// 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 c3d4362a16..43cbd62a63 100644
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -2009,7 +2009,7 @@ static bool isSimpleTemplateIdType(QualType T) {
 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 @@ static bool AdjustFunctionParmAndArgTypesForDeduction(Sema &S,
 /// \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 @@ Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
 /// \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 @@ Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
 /// \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 866d3419f2..76792a0c76 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -713,7 +713,7 @@ public:
   /// different behavior.
   QualType RebuildTemplateSpecializationType(TemplateName Template,
                                              SourceLocation TemplateLoc,
-                                       const TemplateArgumentListInfo &Args);
+                                             TemplateArgumentListInfo &Args);
 
   /// \brief Build a new parenthesized type.
   ///
@@ -747,7 +747,7 @@ public:
                                           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 @@ template<typename Derived>
 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 0000000000..647df2cc0b
--- /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); }
+}