From b19337fbe474a0086d0154421d4b2cedfa8d92a2 Mon Sep 17 00:00:00 2001
From: Richard Smith <richard-llvm@metafoo.co.uk>
Date: Wed, 20 Feb 2013 20:19:27 +0000
Subject: [PATCH] PR15311: Finish implementation of the suggested resolution of
 core issue 1488, which allows grouping parens in an abstract-pack-declarator.
 This was already mostly implemented, but missed some cases. Add an ExtWarn
 for use of this extension until CWG ratifies it.

llvm-svn: 175660
---
 clang/include/clang/Basic/DiagnosticParseKinds.td | 3 +++
 clang/lib/Parse/ParseDecl.cpp                     | 7 +++++++
 clang/test/FixIt/fixit-cxx0x.cpp                  | 2 +-
 clang/test/Parser/cxx0x-ambig.cpp                 | 5 ++++-
 4 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
index a3ad84e..c75241e 100644
--- a/clang/include/clang/Basic/DiagnosticParseKinds.td
+++ b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -470,6 +470,9 @@ def err_parser_impl_limit_overflow : Error<
 def err_misplaced_ellipsis_in_declaration : Error<
   "'...' must %select{immediately precede declared identifier|"
   "be innermost component of anonymous pack declaration}0">;
+def ext_abstract_pack_declarator_parens : ExtWarn<
+  "ISO C++11 requires a parenthesized pack declaration to have a name">,
+  InGroup<DiagGroup<"anonymous-pack-parens">>;
 
 // C++ derived classes
 def err_dup_virtual : Error<"duplicate 'virtual' in base specifier">;
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 8bfdffc..a2045327 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -4439,6 +4439,7 @@ void Parser::ParseDirectDeclarator(Declarator &D) {
         !((D.getContext() == Declarator::PrototypeContext ||
            D.getContext() == Declarator::BlockLiteralContext) &&
           NextToken().is(tok::r_paren) &&
+          !D.hasGroupingParens() &&
           !Actions.containsUnexpandedParameterPacks(D))) {
       SourceLocation EllipsisLoc = ConsumeToken();
       if (isPtrOperatorToken(Tok.getKind(), getLangOpts())) {
@@ -4521,6 +4522,12 @@ void Parser::ParseDirectDeclarator(Declarator &D) {
     // This could be something simple like "int" (in which case the declarator
     // portion is empty), if an abstract-declarator is allowed.
     D.SetIdentifier(0, Tok.getLocation());
+
+    // The grammar for abstract-pack-declarator does not allow grouping parens.
+    // FIXME: Revisit this once core issue 1488 is resolved.
+    if (D.hasEllipsis() && D.hasGroupingParens())
+      Diag(PP.getLocForEndOfToken(D.getEllipsisLoc()),
+           diag::ext_abstract_pack_declarator_parens);
   } else {
     if (Tok.getKind() == tok::annot_pragma_parser_crash)
       LLVM_BUILTIN_TRAP;
diff --git a/clang/test/FixIt/fixit-cxx0x.cpp b/clang/test/FixIt/fixit-cxx0x.cpp
index 3884c64..1f6275f 100644
--- a/clang/test/FixIt/fixit-cxx0x.cpp
+++ b/clang/test/FixIt/fixit-cxx0x.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -verify -std=c++11 %s
+// RUN: %clang_cc1 -verify -std=c++11 -Wno-anonymous-pack-parens %s
 // RUN: cp %s %t
 // RUN: not %clang_cc1 -x c++ -std=c++11 -fixit %t
 // RUN: %clang_cc1 -Wall -pedantic -x c++ -std=c++11 %t
diff --git a/clang/test/Parser/cxx0x-ambig.cpp b/clang/test/Parser/cxx0x-ambig.cpp
index 96e2006..ac9c75e 100644
--- a/clang/test/Parser/cxx0x-ambig.cpp
+++ b/clang/test/Parser/cxx0x-ambig.cpp
@@ -110,7 +110,7 @@ namespace ellipsis {
     void f(S(...args[sizeof(T)])); // expected-note {{here}}
     void f(S(...args)[sizeof(T)]); // expected-error {{redeclared}} expected-note {{here}}
     void f(S ...args[sizeof(T)]); // expected-error {{redeclared}}
-    void g(S(...[sizeof(T)])); // expected-note {{here}}
+    void g(S(...[sizeof(T)])); // expected-note {{here}} expected-warning {{ISO C++11 requires a parenthesized pack declaration to have a name}}
     void g(S(...)[sizeof(T)]); // expected-error {{function cannot return array type}}
     void g(S ...[sizeof(T)]); // expected-error {{redeclared}}
     void h(T(...)); // function type, expected-error {{unexpanded parameter pack}}
@@ -125,5 +125,8 @@ namespace ellipsis {
     void j(T(T...)); // expected-error {{unexpanded parameter pack}}
     void k(int(...)(T)); // expected-error {{cannot return function type}}
     void k(int ...(T));
+    void l(int(&...)(T)); // expected-warning {{ISO C++11 requires a parenthesized pack declaration to have a name}}
+    void l(int(*...)(T)); // expected-warning {{ISO C++11 requires a parenthesized pack declaration to have a name}}
+    void l(int(S<int>::*...)(T)); // expected-warning {{ISO C++11 requires a parenthesized pack declaration to have a name}}
   };
 }
-- 
2.7.4