Bogus warning when comparing nocast short variables

[Pavel Roskin <proski@xxxxxxx>]

Hello!

This test file causes a warning:

typedef short __attribute__((nocast)) u16;
int main(int argc, char **argv)
{
        u16 i = (u16)argc;
        u16 j = (u16)2;
        return (i == j);
}

$ sparse test1.c 
test1.c:6:17: warning: implicit cast from nocast type
test1.c:6:22: warning: implicit cast from nocast type

But this file doesn't cause any warning:

typedef short __attribute__((nocast)) u16;
int main(int argc, char **argv)
{
        u16 i = (u16)argc;
        u16 j = (u16)2;
        switch (i) {
                case j: return 1;;
                default: return 0;;
        }
}

I think the warnings are bogus.  No cast should be needed to compare
variables of the same type.

The warning was actually found in the current Linux kernel, driver
zd1121rw.  A fix was proposed, but I thing the fix belongs to the sparse
code.

-- 
Regards,
Pavel Roskin
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