A byte being shifted right by 8

[Robert Morin]

Hi,

cppcheck didn't detect this problem (neither gcc or clang):

int f( unsigned char TryThis )
{
  return TryThis >> 8;
}

Integer promotion is causing this to be valid but this caused a bug in our system and was not detected until it reached the field.

Worth to add a small test for this ?

[Daniel Marjamäki]

yes. as you say, it's valid so we can only write some "always 0" warning. that seems helpful. Thanks for your suggestion.

I created this ticket:
https://trac.cppcheck.net/ticket/9503

If you are interested.. feel free to investigate this. Probably it would be good if ValueFlow says that the result is always 0.

[Robert Morin]

I will give it a try.

Thanks