Problematic `== true/false` boolean comparisons

[alexhunsley]

@vns

Can you clarify how this affects compile time? I haven’t heard that such thing might make an impact. I can imagine that in optimized builds it might add some time, but these are optimized builds anyway.

So my main source for this is the link I put in the post at top:

Boolean comparison causes extremely slow compilation

Since we moved parts of our codebase to swift, our compile times have effectively quadrupled. Trying to combat this, we've used the function and expression debug time flags to figure out if there's something to be saved by simplifying expressions. Apart from the usual suspects (CGFloat / TimeInterval expressions) being slow, this one seems to be not making a lot of sense to us: public override func hasItems(in: Store) -> Bool { guard let items = store.storage?.items else { return false } r…

Basically the compiler has more stuff to resolve to decide what to do when it sees ==, as opposed to boolExpr or !boolExpr.

Yet another way in which ! and == bool are distinct, despite surface appearances.

(I've not re-validated the finding of slower compilation (yet) so not sure of current performance.)