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Comment by tsbinz | Hacker News Reader

I would be careful with statements like this. New compilers do NOT make this a warning/error, see for example

Note that there are parentheses around the assignment which the compiler takes as an indication that this is intentional. Also note that the parentheses are required because without them the precedence would be wrong.

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Since the parentheses are required due to precedence, then they are not there to show "I intend this assignment to happen". That would have to be:

  if ((options == (__WCLONE|__WALL)) && ((current->uid = 0)))

As an aside, note that this particular case also has the problem that the assignment expression makes the entire test expression false, which is suspicious. If an assignment expression occurs in the controlling expression of a selection or iteration statement, such that the entire expression is always true or false as a result, that should probably be warned about no matter how many parentheses have been heaped on to the assignment.

I'm not saying that a compiler shouldn't flag this. I'm just saying that current compilers don't.

I'd guess that static analysis tools do flag it, but haven't checked.

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