I came here to make this comment. It really needs to be a top-level comment and at the top. I have wasted many hours of my life tracking down buts where the i

I came here to make this comment. It really needs to be a top-level comment and at the top. I have wasted many hours of my life tracking down buts where the idiom in the OP was used in a function. It leads to really hard to find bugs. Beware!!!