Disambiguation of '[[':

 * In C++11, '[[' is ill-formed unless it starts an attribute-specifier. Reject
   array sizes and array indexes which begin with a lambda-expression. Recover by
   parsing the lambda as a lambda.
 * In Objective-C++11, either '[' could be the start of a message-send.
   Fully disambiguate this case: it turns out that the grammars of message-sends,
   lambdas and attributes do not actually overlap. Accept any occurrence of '[['
   where either '[' starts a message send, but reject a lambda in an array index
   just like in C++11 mode.

Implement a couple of changes to the attribute wording which occurred after our
attributes implementation landed:
 * In a function-declaration, the attributes go after the exception specification,
   not after the right paren.
 * A reference type can have attributes applied.
 * An 'identifier' in an attribute can also be a keyword. Support for alternative
   tokens (iso646 keywords) in attributes to follow.

And some bug fixes:
 * Parse attributes after declarator-ids, even if they are not simple identifiers.
 * Do not accept attributes after a parenthesized declarator.
 * Accept attributes after an array size in a new-type-id.
 * Partially disamiguate 'delete' followed by a lambda. More work is required
   here for the case where the lambda-introducer is '[]'.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@154369 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 1 deletions

diff --git a/lib/Parse/ParseExpr.cpp b/lib/Parse/ParseExpr.cpp
index f68359b8d2..7f3a815edc 100644
--- a/lib/Parse/ParseExpr.cpp
+++ b/lib/Parse/ParseExpr.cpp
@@ -1287,7 +1287,12 @@ Parser::ParsePostfixExpressionSuffix(ExprResult LHS) {
       if (getLangOpts().ObjC1 && Tok.isAtStartOfLine() &&
           isSimpleObjCMessageExpression())
         return move(LHS);
-       
+
+      // Reject array indices starting with a lambda-expression. '[[' is
+      // reserved for attributes.
+      if (CheckProhibitedCXX11Attribute())
+        return ExprError();
+
       BalancedDelimiterTracker T(*this, tok::l_square);
       T.consumeOpen();
       Loc = T.getOpenLocation();
@@ -1756,6 +1761,9 @@ ExprResult Parser::ParseBuiltinPrimaryExpression() {
         Comps.back().LocEnd = ConsumeToken();
 
       } else if (Tok.is(tok::l_square)) {
+        if (CheckProhibitedCXX11Attribute())
+          return ExprError();
+
         // offsetof-member-designator: offsetof-member-design '[' expression ']'
         Comps.push_back(Sema::OffsetOfComponent());
         Comps.back().isBrackets = true;