[c++1z] P0195R2: Allow multiple using-declarators in a single using-declaration.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@289905 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 45 insertions, 13 deletions

diff --git a/include/clang/Basic/DiagnosticParseKinds.td b/include/clang/Basic/DiagnosticParseKinds.td
index 8aa3e1ccb3..f6d8b3ad54 100644
--- a/include/clang/Basic/DiagnosticParseKinds.td
+++ b/include/clang/Basic/DiagnosticParseKinds.td
@@ -741,6 +741,15 @@ def err_alias_declaration_not_identifier : Error<
 def err_alias_declaration_specialization : Error<
   "%select{partial specialization|explicit specialization|explicit instantiation}0 of alias templates is not permitted">;
 
+// C++1z using-declaration pack expansions
+def ext_multi_using_declaration : ExtWarn<
+  "use of multiple declarators in a single using declaration is "
+  "a C++1z extension">, InGroup<CXX1z>;
+def warn_cxx1z_compat_multi_using_declaration : Warning<
+  "use of multiple declarators in a single using declaration is "
+  "incompatible with C++ standards before C++1z">,
+  InGroup<CXXPre1zCompat>, DefaultIgnore;
+
 // C++11 override control
 def ext_override_control_keyword : ExtWarn<
   "'%0' keyword is a C++11 extension">, InGroup<CXX11>;
diff --git a/include/clang/Parse/Parser.h b/include/clang/Parse/Parser.h
index c956aaeffc..3d098fab84 100644
--- a/include/clang/Parse/Parser.h
+++ b/include/clang/Parse/Parser.h
@@ -1261,6 +1261,11 @@ private:
     ParsedAttributesWithRange(AttributeFactory &factory)
       : ParsedAttributes(factory) {}
 
+    void clear() {
+      ParsedAttributes::clear();
+      Range = SourceRange();
+    }
+
     SourceRange Range;
   };
 
@@ -2418,21 +2423,41 @@ private:
                            BalancedDelimiterTracker &Tracker);
   Decl *ParseLinkage(ParsingDeclSpec &DS, unsigned Context);
   Decl *ParseExportDeclaration();
-  Decl *ParseUsingDirectiveOrDeclaration(unsigned Context,
-                                         const ParsedTemplateInfo &TemplateInfo,
-                                         SourceLocation &DeclEnd,
-                                         ParsedAttributesWithRange &attrs,
-                                         Decl **OwnedType = nullptr);
+  DeclGroupPtrTy ParseUsingDirectiveOrDeclaration(
+      unsigned Context, const ParsedTemplateInfo &TemplateInfo,
+      SourceLocation &DeclEnd, ParsedAttributesWithRange &attrs);
   Decl *ParseUsingDirective(unsigned Context,
                             SourceLocation UsingLoc,
                             SourceLocation &DeclEnd,
                             ParsedAttributes &attrs);
-  Decl *ParseUsingDeclaration(unsigned Context,
-                              const ParsedTemplateInfo &TemplateInfo,
-                              SourceLocation UsingLoc,
-                              SourceLocation &DeclEnd,
-                              AccessSpecifier AS = AS_none,
-                              Decl **OwnedType = nullptr);
+
+  struct UsingDeclarator {
+    SourceLocation TypenameLoc;
+    CXXScopeSpec SS;
+    SourceLocation TemplateKWLoc;
+    UnqualifiedId Name;
+
+    void clear() {
+      TypenameLoc = TemplateKWLoc = SourceLocation();
+      SS.clear();
+      Name.clear();
+    }
+  };
+
+  bool ParseUsingDeclarator(unsigned Context, UsingDeclarator &D);
+  DeclGroupPtrTy ParseUsingDeclaration(unsigned Context,
+                                       const ParsedTemplateInfo &TemplateInfo,
+                                       SourceLocation UsingLoc,
+                                       SourceLocation &DeclEnd,
+                                       AccessSpecifier AS = AS_none);
+  Decl *ParseAliasTemplate(const ParsedTemplateInfo &TemplateInfo,
+                           SourceLocation &DeclEnd, AccessSpecifier AS,
+                           ParsedAttributesWithRange &MisplacedAttrs1);
+  Decl *ParseAliasDeclarationAfterDeclarator(
+      const ParsedTemplateInfo &TemplateInfo, SourceLocation UsingLoc,
+      UsingDeclarator &D, SourceLocation &DeclEnd, AccessSpecifier AS,
+      ParsedAttributes &Attrs, Decl **OwnedType = nullptr);
+
   Decl *ParseStaticAssertDeclaration(SourceLocation &DeclEnd);
   Decl *ParseNamespaceAlias(SourceLocation NamespaceLoc,
                             SourceLocation AliasLoc, IdentifierInfo *Alias,
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index 2028d2cd78..e5b08b01a7 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -4341,12 +4341,10 @@ public:
 
   Decl *ActOnUsingDeclaration(Scope *CurScope,
                               AccessSpecifier AS,
-                              bool HasUsingKeyword,
                               SourceLocation UsingLoc,
                               CXXScopeSpec &SS,
                               UnqualifiedId &Name,
                               AttributeList *AttrList,
-                              bool HasTypenameKeyword,
                               SourceLocation TypenameLoc);
   Decl *ActOnAliasDeclaration(Scope *CurScope,
                               AccessSpecifier AS,