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.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@127092 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/AST/DeclTemplate.h b/include/clang/AST/DeclTemplate.h
index 9c20969..eaadc81 100644
--- a/include/clang/AST/DeclTemplate.h
+++ b/include/clang/AST/DeclTemplate.h
@@ -771,9 +771,20 @@
   /// \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 @@
     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/lib/AST/DeclTemplate.cpp b/lib/AST/DeclTemplate.cpp
index 1ef47b9..fe7c9e2 100644
--- a/lib/AST/DeclTemplate.cpp
+++ b/lib/AST/DeclTemplate.cpp
@@ -163,6 +163,49 @@
   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 @@
   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 @@
   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/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index 4e1976e..4108e9f 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -95,6 +95,12 @@
         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/test/SemaTemplate/issue150.cpp b/test/SemaTemplate/issue150.cpp
index 2cfa8c5..6124d05 100644
--- a/test/SemaTemplate/issue150.cpp
+++ b/test/SemaTemplate/issue150.cpp
@@ -91,7 +91,17 @@
     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>();
   }
 }