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re PR c++/57 ([DR 325] GCC can't parse a non-parenthesized comma in a template-id within a default argument)

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PR c++/57
        * parser.c (cp_parser_parameter_declaration): Handle < ambiguity
        in default arguments.

Co-Authored-By: Liu Guanwei <liu_gw@163.com>

From-SVN: r134762
This commit is contained in:
Jason Merrill 2008-04-28 16:43:27 -04:00 committed by Jason Merrill
parent d6b68fccba
commit bda3795274
3 changed files with 56 additions and 9 deletions
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7
gcc/cp/ChangeLog
View File

@ -1,3 +1,10 @@
2008-04-28 Jason Merrill <jason@redhat.com>
Liu Guanwei <liu_gw@163.com>
PR c++/57
* parser.c (cp_parser_parameter_declaration): Handle < ambiguity
in default arguments.
2008-04-25 Jan Hubicka <jh@suse.cz>
* typeck.c (check_return_expr): Update.

50
gcc/cp/parser.c
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@ -13723,6 +13723,7 @@ cp_parser_parameter_declaration (cp_parser *parser,
&& TYPE_BEING_DEFINED (current_class_type))
{
unsigned depth = 0;
int maybe_template_id = 0;
cp_token *first_token;
cp_token *token;
@ -13741,6 +13742,33 @@ cp_parser_parameter_declaration (cp_parser *parser,
/* In valid code, a default argument must be
immediately followed by a `,' `)', or `...'. */
case CPP_COMMA:
if (depth == 0 && maybe_template_id)
{
/* If we've seen a '<', we might be in a
template-argument-list. Until Core issue 325 is
resolved, we don't know how this situation ought
to be handled, so try to DTRT. We check whether
what comes after the comma is a valid parameter
declaration list. If it is, then the comma ends
the default argument; otherwise the default
argument continues. */
bool error = false;
/* Set ITALP so cp_parser_parameter_declaration_list
doesn't decide to commit to this parse. */
bool saved_italp = parser->in_template_argument_list_p;
parser->in_template_argument_list_p = true;
cp_parser_parse_tentatively (parser);
cp_lexer_consume_token (parser->lexer);
cp_parser_parameter_declaration_list (parser, &error);
if (!cp_parser_error_occurred (parser) && !error)
done = true;
cp_parser_abort_tentative_parse (parser);
parser->in_template_argument_list_p = saved_italp;
break;
}
case CPP_CLOSE_PAREN:
case CPP_ELLIPSIS:
/* If we run into a non-nested `;', `}', or `]',
@ -13764,6 +13792,13 @@ cp_parser_parameter_declaration (cp_parser *parser,
++depth;
break;
case CPP_LESS:
if (depth == 0)
/* This might be the comparison operator, or it might
start a template argument list. */
++maybe_template_id;
break;
case CPP_RSHIFT:
if (cxx_dialect == cxx98)
break;
@ -13772,11 +13807,16 @@ cp_parser_parameter_declaration (cp_parser *parser,
cases. */
case CPP_GREATER:
/* If we see a non-nested `>', and `>' is not an
operator, then it marks the end of the default
argument. */
if (!depth && !greater_than_is_operator_p)
done = true;
if (depth == 0)
{
/* This might be an operator, or it might close a
template argument list. But if a previous '<'
started a template argument list, this will have
closed it, so we can't be in one anymore. */
maybe_template_id -= 1 + (token->type == CPP_RSHIFT);
if (maybe_template_id < 0)
maybe_template_id = 0;
}
break;
/* If we run out of tokens, issue an error message. */

8
gcc/testsuite/g++.old-deja/g++.pt/defarg8.C
View File

@ -3,15 +3,15 @@
// Default arguments containing more than one non-nested explicit
// template argument leads to parse error
// This might be ill formed. See DR 325 (which would like to make it
// so)
// This might be ill formed. See DR 325 (one proposed resolution is to make
// it so)
template <class T> class foo1;
template <class T, class U> class foo2; // { dg-error "" }
template <class T, class U> class foo2;
struct bar {
template <class T, class U>
bar(int i = foo1<T>::baz, // { dg-bogus "" } -
int j = int(foo2<T, U>::baz), // ok
int k = foo2<T, U>::baz) {} // { dg-error "" }
int k = foo2<T, U>::baz) {} // ok?
};