The patch currently issues a false positive for the test case
below. I suspect the chain might need to be cleared after each
condition that involves a side-effect.
int foo (int a)
{
if (a) return 1; else if (++a) return 2; else if (a) return 3;
return 0;
}
But the last branch here can never be reached, right? If a == 0, foo
returns 2, otherwise it just returns 1. So I think we should diagnose
this.
It probably wasn't the best example. The general issue here is
that the second condition has a side-effect that can change (in
this case clearly does) the value of the expression.
Here's a better example:
int a;
int bar (void) { a = 1; return 0; }
int foo (void) {
if (a) return 1;
else if (foo ()) return 2;
else if (a) return 3;
return 0;
}
Since we don't know bar's side-effects we must assume they change
the value of a and so we must avoid diagnosing the third if.
Martin
