Expansion of printk in dprintk in TrailingConditionalVariadicMacro test case cause if (debug) to disappear.

[pgoodman]

Then after expanding printk:

[pgoodman]

We can see the issue here:

The macro name printk ends up on the right-hand side of an after expansion, lead by if (debug), but this all exists on the before side of another expansion. This is now triggering an assertion in the indexer.

[pgoodman]

This is a simpler, albeit eviler test case:

#define Y 1
#define X Y
#define A if (1) B
#define B(a) return C
#define C(a) a

int main() {
  A(Y)(X);
  return 0;
}

[pgoodman]

Not yet fixed, this is what the token tree looks like: