[Bug c/47102] New: error message "duplicate member" in error ?

[Bug c/47102] New: error message "duplicate member" in error ?

[dcb314 at hotmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47102

           Summary: error message "duplicate member" in error ?
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: dcb314@hotmail.com


I just tried to compile the following C code with the latest 4.6 snapshot
20101225 on a Linux x86_64 box. It is derived from code in the Linux
kernel.

typedef int dma_addr_t;
typedef unsigned short u16;
typedef unsigned long u64;

struct igbvf_buffer {
    dma_addr_t dma;
    struct sk_buff *skb;
    union {
        /* Tx */
        struct {
            unsigned long time_stamp;
            u16 length;
            u16 next_to_watch;
            u16 mapped_as_page;
        };
        /* Rx */
        struct {
            struct page *page;
            u64 page_dma;
            unsigned int page_offset;
        };
    };
    struct page *page;
};

The compiler said

bug15.c:25:18: error: duplicate member 'page'

I've tried the same source code on Comeau C and it finds no error.

[Bug c/47102] error message "duplicate member" in error ?

[jsm28 at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47102

--- Comment #1 from Joseph S. Myers <jsm28 at gcc dot gnu.org> 2010-12-29 11:43:20 UTC ---
The diagnostic is correct; the code is invalid; C1X requires this to be
diagnosed; it is ambiguous whether "page" refers to an element directly in the
struct or one accessed via the anonymous union therein.  See bug 4784.

[Bug c/47102] error message "duplicate member" in error ?

[jsm28 at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47102

Joseph S. Myers <jsm28 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID

--- Comment #2 from Joseph S. Myers <jsm28 at gcc dot gnu.org> 2010-12-29 11:44:07 UTC ---
Not a bug.