Support for C++11 (non-template) alias declarations.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@129567 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 44 insertions, 10 deletions

diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index a384fab935..119bf0f762 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -253,7 +253,7 @@ Decl *Parser::ParseUsingDirectiveOrDeclaration(unsigned Context,
     return ParseUsingDirective(Context, UsingLoc, DeclEnd, attrs);
   }
 
-  // Otherwise, it must be a using-declaration.
+  // Otherwise, it must be a using-declaration or an alias-declaration.
 
   // Using declarations can't have attributes.
   ProhibitAttributes(attrs);
@@ -323,14 +323,17 @@ Decl *Parser::ParseUsingDirective(unsigned Context,
                                      IdentLoc, NamespcName, attrs.getList());
 }
 
-/// ParseUsingDeclaration - Parse C++ using-declaration. Assumes that
-/// 'using' was already seen.
+/// ParseUsingDeclaration - Parse C++ using-declaration or alias-declaration.
+/// Assumes that 'using' was already seen.
 ///
 ///     using-declaration: [C++ 7.3.p3: namespace.udecl]
 ///       'using' 'typename'[opt] ::[opt] nested-name-specifier
 ///               unqualified-id
 ///       'using' :: unqualified-id
 ///
+///     alias-declaration: C++0x [decl.typedef]p2
+///       'using' identifier = type-id ;
+///
 Decl *Parser::ParseUsingDeclaration(unsigned Context,
                                     const ParsedTemplateInfo &TemplateInfo,
                                     SourceLocation UsingLoc,
@@ -340,10 +343,6 @@ Decl *Parser::ParseUsingDeclaration(unsigned Context,
   SourceLocation TypenameLoc;
   bool IsTypeName;
 
-  // TODO: in C++0x, if we have template parameters this must be a
-  // template alias:
-  //   template <...> using id = type;
-
   // Ignore optional 'typename'.
   // FIXME: This is wrong; we should parse this as a typename-specifier.
   if (Tok.is(tok::kw_typename)) {
@@ -377,17 +376,48 @@ Decl *Parser::ParseUsingDeclaration(unsigned Context,
     return 0;
   }
 
-  // Parse (optional) attributes (most likely GNU strong-using extension).
   ParsedAttributes attrs(AttrFactory);
-  MaybeParseGNUAttributes(attrs);
+
+  // Maybe this is an alias-declaration.
+  bool IsAliasDecl = Tok.is(tok::equal);
+  TypeResult TypeAlias;
+  if (IsAliasDecl) {
+    // TODO: Do we want to support attributes somewhere in an alias declaration?
+    // Can't follow GCC since it doesn't support them yet!
+    ConsumeToken();
+
+    if (!getLang().CPlusPlus0x)
+      Diag(Tok.getLocation(), diag::ext_alias_declaration);
+
+    // Name must be an identifier.
+    if (Name.getKind() != UnqualifiedId::IK_Identifier) {
+      Diag(Name.StartLocation, diag::err_alias_declaration_not_identifier);
+      // No removal fixit: can't recover from this.
+      SkipUntil(tok::semi);
+      return 0;
+    } else if (IsTypeName)
+      Diag(TypenameLoc, diag::err_alias_declaration_not_identifier)
+        << FixItHint::CreateRemoval(SourceRange(TypenameLoc,
+                             SS.isNotEmpty() ? SS.getEndLoc() : TypenameLoc));
+    else if (SS.isNotEmpty())
+      Diag(SS.getBeginLoc(), diag::err_alias_declaration_not_identifier)
+        << FixItHint::CreateRemoval(SS.getRange());
+
+    TypeAlias = ParseTypeName(0, Declarator::AliasDeclContext);
+  } else
+    // Parse (optional) attributes (most likely GNU strong-using extension).
+    MaybeParseGNUAttributes(attrs);
 
   // Eat ';'.
   DeclEnd = Tok.getLocation();
   ExpectAndConsume(tok::semi, diag::err_expected_semi_after,
-                   !attrs.empty() ? "attributes list" : "using declaration",
+                   !attrs.empty() ? "attributes list" :
+                   IsAliasDecl ? "alias declaration" : "using declaration",
                    tok::semi);
 
   // Diagnose an attempt to declare a templated using-declaration.
+  // TODO: in C++0x, alias-declarations can be templates:
+  //   template <...> using id = type;
   if (TemplateInfo.Kind) {
     SourceRange R = TemplateInfo.getSourceRange();
     Diag(UsingLoc, diag::err_templated_using_declaration)
@@ -399,6 +429,10 @@ Decl *Parser::ParseUsingDeclaration(unsigned Context,
     return 0;
   }
 
+  if (IsAliasDecl)
+    return Actions.ActOnAliasDeclaration(getCurScope(), AS, UsingLoc, Name,
+                                         TypeAlias);
+
   return Actions.ActOnUsingDeclaration(getCurScope(), AS, true, UsingLoc, SS,
                                        Name, attrs.getList(),
                                        IsTypeName, TypenameLoc);