Check for unexpanded parameter packs in friend declarations.

llvm-svn: 121934

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -1824,22 +1824,22 @@ def note_template_parameter_pack_here : Note<
 def err_unexpanded_parameter_pack_0 : Error<
   "%select{expression|base type|declaration type|data member type|bit-field "
   "size|static assertion|fixed underlying type|enumerator value|"
-  "using declaration}0 "
+  "using declaration|friend declaration|qualifier}0 "
   "contains an unexpanded parameter pack">;
 def err_unexpanded_parameter_pack_1 : Error<
   "%select{expression|base type|declaration type|data member type|bit-field "
   "size|static assertion|fixed underlying type|enumerator value|"
-  "using declaration}0 "
+  "using declaration|friend declaration|qualifier}0 "
   "contains unexpanded parameter pack %1">;
 def err_unexpanded_parameter_pack_2 : Error<
   "%select{expression|base type|declaration type|data member type|bit-field "
   "size|static assertion|fixed underlying type|enumerator value|"
-  "using declaration}0 "
+  "using declaration|friend declaration|qualifier}0 "
   "contains unexpanded parameter packs %1 and %2">;
 def err_unexpanded_parameter_pack_3_or_more : Error<
   "%select{expression|base type|declaration type|data member type|bit-field "
   "size|static assertion|fixed underlying type|enumerator value|"
-  "using declaration}0 "
+  "using declaration|friend declaration|qualifier}0 "
   "contains unexpanded parameter packs %1, %2, ...">;
 
 def err_unexpected_typedef : Error<

clang/include/clang/Sema/Sema.h

@@ -3160,7 +3160,13 @@ public:
     UPPC_EnumeratorValue,
 
     /// \brief A using declaration.
-    UPPC_UsingDeclaration
+    UPPC_UsingDeclaration,
+
+    /// \brief A friend declaration.
+    UPPC_FriendDeclaration,
+
+    /// \brief A declaration qualifier.
+    UPPC_DeclarationQualifier
   };
 
   /// \brief If the given type contains an unexpanded parameter pack,

clang/lib/Sema/SemaDecl.cpp

@@ -2332,6 +2332,10 @@ Decl *Sema::HandleDeclarator(Scope *S, Declarator &D,
   if (D.getCXXScopeSpec().isInvalid())
     D.setInvalidType();
   else if (D.getCXXScopeSpec().isSet()) {
+    if (DiagnoseUnexpandedParameterPack(D.getCXXScopeSpec(), 
+                                        UPPC_DeclarationQualifier))
+      return 0;
+
     bool EnteringContext = !D.getDeclSpec().isFriendSpecified();
     DC = computeDeclContext(D.getCXXScopeSpec(), EnteringContext);
     if (!DC) {

clang/lib/Sema/SemaDeclCXX.cpp

@@ -6383,6 +6383,9 @@ Decl *Sema::ActOnFriendTypeDecl(Scope *S, const DeclSpec &DS,
   if (TheDeclarator.isInvalidType())
     return 0;
 
+  if (DiagnoseUnexpandedParameterPack(Loc, TSI, UPPC_FriendDeclaration))
+    return 0;
+
   // This is definitely an error in C++98.  It's probably meant to
   // be forbidden in C++0x, too, but the specification is just
   // poorly written.
@@ -6482,6 +6485,12 @@ Decl *Sema::ActOnFriendFunctionDecl(Scope *S, Declarator &D, bool IsDefinition,
   DeclarationName Name = NameInfo.getName();
   assert(Name);
 
+  // Check for unexpanded parameter packs.
+  if (DiagnoseUnexpandedParameterPack(Loc, TInfo, UPPC_FriendDeclaration) ||
+      DiagnoseUnexpandedParameterPack(NameInfo, UPPC_FriendDeclaration) ||
+      DiagnoseUnexpandedParameterPack(SS, UPPC_FriendDeclaration))
+    return 0;
+
   // The context we found the declaration in, or in which we should
   // create the declaration.
   DeclContext *DC;

clang/test/CXX/temp/temp.decls/temp.variadic/p5.cpp

@@ -121,6 +121,10 @@ struct TestUnexpandedDecls : T{
   using typename Types::type; // expected-error{{using declaration contains unexpanded parameter pack 'Types'}}
   using Types::value; // expected-error{{using declaration contains unexpanded parameter pack 'Types'}}
   using T::operator Types; // expected-error{{using declaration contains unexpanded parameter pack 'Types'}}
+
+  friend class Types::foo; // expected-error{{friend declaration contains unexpanded parameter pack 'Types'}}
+  friend void friend_func(Types); // expected-error{{friend declaration contains unexpanded parameter pack 'Types'}}
+  friend void Types::other_friend_func(int); // expected-error{{friend declaration contains unexpanded parameter pack 'Types'}}
 };
 
 // Test for diagnostics in the presence of multiple unexpanded