Bug 36320 – Required diagnosis of syntax error missed

Bug 36320 - Required diagnosis of syntax error missed


Summary:	Required diagnosis of syntax error missed

Status:	RESOLVED FIXED

Product:	gcc
Classification:	Unclassified
Component:	preprocessor
Version:	4.1.3

Importance:	P3 normal
Target Milestone:	4.4.0
Assigned To:	Tom Tromey

URL:
Keywords:

Depends on:	36453
Blocks:
	Show dependency tree / graph

Reported:	2008-05-24 10:55 UTC by Neil Booth
Modified:	2008-06-06 20:03 UTC (History)
CC List:	2 users (show)

See Also:
Host:
Target:
Build:
Known to work:
Known to fail:
Last reconfirmed:	2008-05-24 18:04:32

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Description Neil Booth 2008-05-24 10:55:37 UTC

The syntax error in #elif below is not diagnosed with (say) --std=c99
-pedantic-errors.

int z;
#if 1
#elif
#endif

Syntax is:

elif-group:
        # elif constant-expression new-line groupopt

and constant expression cannot be empty.  The syntax relaxation of 6.10p4 does
not apply as the group that the #elif lies in (beginning with the #if) is not
skipped.

Comment 1 Tom Tromey 2008-05-24 16:21:05 UTC

Confirmed.  This seems like a weird design to me, but my reading of the
standard text agrees with yours.

Comment 2 Tom Tromey 2008-05-24 18:04:32 UTC

Testing a patch.

Comment 3 Tom Tromey 2008-05-30 14:25:55 UTC

Subject: Bug 36320

Author: tromey
Date: Fri May 30 14:25:09 2008
New Revision: 136209

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=136209
Log:
gcc/testsuite
    PR preprocessor/36320:
    * gcc.dg/cpp/pr36320.c: New file.
libcpp
    PR preprocessor/36320:
    * internal.h (_cpp_parse_expr): Update.
    * expr.c (_cpp_parse_expr): Add 'is_if' argument.  Update error
    messages.
    * directives.c (do_if): Update.
    (do_elif): Require expression if processing group.

Added:
    trunk/gcc/testsuite/gcc.dg/cpp/pr36320.c
Modified:
    trunk/gcc/testsuite/ChangeLog
    trunk/libcpp/ChangeLog
    trunk/libcpp/directives.c
    trunk/libcpp/expr.c
    trunk/libcpp/internal.h

Comment 4 Tom Tromey 2008-05-30 15:07:04 UTC

Fixed on trunk.