[Bug c/45977] "warning: 'i' initialized and declared 'extern'" is spurious

[cascardo at holoscopio dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45977

Thadeu Lima de Souza Cascardo <cascardo at holoscopio dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |cascardo at holoscopio dot
                   |                            |com

--- Comment #4 from Thadeu Lima de Souza Cascardo <cascardo at holoscopio dot com> 2011-05-09 03:49:25 UTC ---
What seemed really strange to me is that the warning would be emitted even when
the static declaration was inside #if 0/#endif pair, since the pre-processor
would have removed the code entirely.

And reading the warning also told me the problem was assigning a value in the
extern declaration.

So

extern int i = 3;

is not fine. While

static int i = 3;
extern int i;

is perfectly OK. That is, without any warning on/off flags, there is no
warning. Should there be such a warning as Joseph says? -Wall -Wextra emits no
warning for static int i; extern int i; case. In fact, there is
-Wredundant-decls, but it only works if there is no initialization in the
extern declaration.

I can turn off this warning using -w, but there is no particular flag for this
warning. Should one of the existing flags be used or a new one be created?
Better yet, should gcc not warn when this initialization happens in this
particular case, when the variable has already been declared as static?