When determining template instantiation arguments within a function

template (not a specialization!), use the "injected" function template
arguments, which correspond to the template parameters of the function
template. This is required when substituting into the default template
parameters of template template parameters within a function template.

Fixes PR9016.

llvm-svn: 127092

4 files changed, 95 insertions, 38 deletions

diff --git a/clang/include/clang/AST/DeclTemplate.h b/clang/include/clang/AST/DeclTemplate.h
index 9c20969c1f5..eaadc8132af 100644
--- a/clang/include/clang/AST/DeclTemplate.h
+++ b/clang/include/clang/AST/DeclTemplate.h
@@ -771,9 +771,20 @@ protected:
   /// \brief Data that is common to all of the declarations of a given
   /// function template.
   struct Common : CommonBase {
+    Common() : InjectedArgs(0) { }
+    
     /// \brief The function template specializations for this function
     /// template, including explicit specializations and instantiations.
     llvm::FoldingSet<FunctionTemplateSpecializationInfo> Specializations;
+    
+    /// \brief The set of "injected" template arguments used within this
+    /// function template.
+    ///
+    /// This pointer refers to the template arguments (there are as
+    /// many template arguments as template parameaters) for the function
+    /// template, and is allocated lazily, since most function templates do not
+    /// require the use of this information.
+    TemplateArgument *InjectedArgs;
   };
 
   FunctionTemplateDecl(DeclContext *DC, SourceLocation L, DeclarationName Name,
@@ -844,6 +855,15 @@ public:
     return makeSpecIterator(getSpecializations(), true);
   }
 
+  /// \brief Retrieve the "injected" template arguments that correspond to the
+  /// template parameters of this function template.
+  ///                               
+  /// Although the C++ standard has no notion of the "injected" template
+  /// arguments for a function template, the notion is convenient when
+  /// we need to perform substitutions inside the definition of a function
+  /// template.     
+  std::pair<const TemplateArgument *, unsigned> getInjectedTemplateArgs();
+                               
   /// \brief Create a function template node.
   static FunctionTemplateDecl *Create(ASTContext &C, DeclContext *DC,
                                       SourceLocation L,
diff --git a/clang/lib/AST/DeclTemplate.cpp b/clang/lib/AST/DeclTemplate.cpp
index 1ef47b9158b..fe7c9e2904f 100644
--- a/clang/lib/AST/DeclTemplate.cpp
+++ b/clang/lib/AST/DeclTemplate.cpp
@@ -163,6 +163,49 @@ RedeclarableTemplateDecl::findSpecializationImpl(
   return Entry ? SETraits::getMostRecentDeclaration(Entry) : 0;
 }
 
+/// \brief Generate the injected template arguments for the given template
+/// parameter list, e.g., for the injected-class-name of a class template.
+static void GenerateInjectedTemplateArgs(ASTContext &Context,
+                                        TemplateParameterList *Params,
+                                         TemplateArgument *Args) {
+  for (TemplateParameterList::iterator Param = Params->begin(),
+                                    ParamEnd = Params->end();
+       Param != ParamEnd; ++Param) {
+    TemplateArgument Arg;
+    if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
+      QualType ArgType = Context.getTypeDeclType(TTP);
+      if (TTP->isParameterPack())
+        ArgType = Context.getPackExpansionType(ArgType, 
+                                               llvm::Optional<unsigned>());
+      
+      Arg = TemplateArgument(ArgType);
+    } else if (NonTypeTemplateParmDecl *NTTP =
+               dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
+      Expr *E = new (Context) DeclRefExpr(NTTP,
+                                  NTTP->getType().getNonLValueExprType(Context),
+                                  Expr::getValueKindForType(NTTP->getType()),
+                                          NTTP->getLocation());
+      
+      if (NTTP->isParameterPack())
+        E = new (Context) PackExpansionExpr(Context.DependentTy, E,
+                                            NTTP->getLocation(),
+                                            llvm::Optional<unsigned>());
+      Arg = TemplateArgument(E);
+    } else {
+      TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*Param);
+      if (TTP->isParameterPack())
+        Arg = TemplateArgument(TemplateName(TTP), llvm::Optional<unsigned>());
+      else
+        Arg = TemplateArgument(TemplateName(TTP));
+    }
+    
+    if ((*Param)->isTemplateParameterPack())
+      Arg = TemplateArgument::CreatePackCopy(Context, &Arg, 1);
+    
+    *Args++ = Arg;
+  }
+}
+                                      
 //===----------------------------------------------------------------------===//
 // FunctionTemplateDecl Implementation
 //===----------------------------------------------------------------------===//
@@ -199,6 +242,20 @@ FunctionTemplateDecl::findSpecialization(const TemplateArgument *Args,
   return findSpecializationImpl(getSpecializations(), Args, NumArgs, InsertPos);
 }
 
+std::pair<const TemplateArgument *, unsigned> 
+FunctionTemplateDecl::getInjectedTemplateArgs() {
+  TemplateParameterList *Params = getTemplateParameters();
+  Common *CommonPtr = getCommonPtr();
+  if (!CommonPtr->InjectedArgs) {
+    CommonPtr->InjectedArgs
+      = new (getASTContext()) TemplateArgument [Params->size()];
+    GenerateInjectedTemplateArgs(getASTContext(), Params, 
+                                 CommonPtr->InjectedArgs);
+  }
+  
+  return std::make_pair(CommonPtr->InjectedArgs, Params->size());
+}
+
 //===----------------------------------------------------------------------===//
 // ClassTemplateDecl Implementation
 //===----------------------------------------------------------------------===//
@@ -343,44 +400,8 @@ ClassTemplateDecl::getInjectedClassNameSpecialization() {
   ASTContext &Context = getASTContext();
   TemplateParameterList *Params = getTemplateParameters();
   llvm::SmallVector<TemplateArgument, 16> TemplateArgs;
-  TemplateArgs.reserve(Params->size());
-  for (TemplateParameterList::iterator Param = Params->begin(),
-                                    ParamEnd = Params->end();
-       Param != ParamEnd; ++Param) {
-    TemplateArgument Arg;
-    if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
-      QualType ArgType = Context.getTypeDeclType(TTP);
-      if (TTP->isParameterPack())
-        ArgType = Context.getPackExpansionType(ArgType, 
-                                               llvm::Optional<unsigned>());
-      
-      Arg = TemplateArgument(ArgType);
-    } else if (NonTypeTemplateParmDecl *NTTP =
-                 dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
-      Expr *E = new (Context) DeclRefExpr(NTTP,
-                                  NTTP->getType().getNonLValueExprType(Context),
-                                  Expr::getValueKindForType(NTTP->getType()),
-                                          NTTP->getLocation());
-
-      if (NTTP->isParameterPack())
-        E = new (Context) PackExpansionExpr(Context.DependentTy, E,
-                                            NTTP->getLocation(),
-                                            llvm::Optional<unsigned>());
-      Arg = TemplateArgument(E);
-    } else {
-      TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(*Param);
-      if (TTP->isParameterPack())
-        Arg = TemplateArgument(TemplateName(TTP), llvm::Optional<unsigned>());
-      else
-        Arg = TemplateArgument(TemplateName(TTP));
-    }
-    
-    if ((*Param)->isTemplateParameterPack())
-      Arg = TemplateArgument::CreatePackCopy(Context, &Arg, 1);
-    
-    TemplateArgs.push_back(Arg);
-  }
-
+  TemplateArgs.resize(Params->size());
+  GenerateInjectedTemplateArgs(getASTContext(), Params, TemplateArgs.data());
   CommonPtr->InjectedClassNameType
     = Context.getTemplateSpecializationType(TemplateName(this),
                                             &TemplateArgs[0],
diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index 4e1976e322d..4108e9fd6fa 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -95,6 +95,12 @@ Sema::getTemplateInstantiationArgs(NamedDecl *D,
         assert(Function->getPrimaryTemplate() && "No function template?");
         if (Function->getPrimaryTemplate()->isMemberSpecialization())
           break;
+      } else if (FunctionTemplateDecl *FunTmpl
+                                   = Function->getDescribedFunctionTemplate()) {
+        // Add the "injected" template arguments.
+        std::pair<const TemplateArgument *, unsigned>
+          Injected = FunTmpl->getInjectedTemplateArgs();
+        Result.addOuterTemplateArguments(Injected.first, Injected.second);
       }
       
       // If this is a friend declaration and it declares an entity at
diff --git a/clang/test/SemaTemplate/issue150.cpp b/clang/test/SemaTemplate/issue150.cpp
index 2cfa8c5cb1e..6124d05413a 100644
--- a/clang/test/SemaTemplate/issue150.cpp
+++ b/clang/test/SemaTemplate/issue150.cpp
@@ -91,7 +91,17 @@ namespace PR9016 {
     IntervalSet<T> IntervalSetT;
   };
   
+  template <class T, 
+            template<class _T, template<class> class Compare = less,
+                     class = typename interval_type_default<_T,Compare>::type,
+                     template<class> class = allocator> class IntervalSet>
+  void int40()
+  {
+    IntervalSet<T> IntervalSetT;
+  }
+
   void test() {
     ZZZ<int, interval_set> zzz;
+    int40<int, interval_set>();
   }
 }