Consider this C++:

int main (void)
{
	double foo[4096];
	((char *)(foo))[(sizeof(foo)-1)] = '\0';
	
	return 0;
}

It outputs:

test.cp:4:12: warning: array index of '32767' indexes past the end of an array (that contains 4096 elements) [-Warray-bounds]
        ((char *)(foo))[(sizeof(foo)-1)] = '\0';
                  ^      ~~~~~~~~~~~~~

It's a false positive.  Note the cast to char*.

This is with clang version 3.0 (trunk 138577).