While I would find the warning less misleading if it simply said
in all three cases: "the address of 'x' will always evaluate as
‘true’" I think it would be even more accurate if it said
"the address of 'x' may be assumed to evaluate to ‘true’" That
avoids making claims about whether or not it actually is null,
doesn't talk about the NULL macro when one isn't used in the
code, and by saying "may assume" it allows for both making
the assumption as well as not making one.
That sounds good except that talking about 'true' is wrong when there is
an explicit comparison to a null pointer constant. I'd be fine with
changing "NULL" to "null" or similar.
Sounds good. I will use bug 47931 - missing -Waddress warning
for comparison with NULL, to take care of the outstanding cases
where a warning still isn't issued (in either C++ or C) and also
adjust the text of the warning.
Martin
PS It seems that just adding STRIP_NOPS (op) to Marek's patch
significantly increases the number of successfully diagnosed
cases. (The small patch I attached to 47931 covers nearly all
the remaining cases I could think of.)
