cc @xedin

Actually, this no longer produces that diagnostic on Swift 5 (Xcode 10.2.1).

You'd probably get faster type-checking if you left out the conversions to UInt32. You may actually be getting different behavior from what you expect there, because UInt32(a >> b) is very different from a >> b as UInt32.

Comment by Anders Kierulf (JIRA)

This was indeed with Xcode 10.2.1, Swift 5, so surprised you're not seeing it.

I added the extra UInt32 in a previous version to speed up type checks, helped at that point. The behavior should be the same as long as there's guaranteed to be no overflow, right? The following is even slower to type check:

let result: UInt32 = UInt32(bit \| (bit \<\< offset1) \| (bit \<\< offset2) \| (bit \<\< offset3))

But the following is fast:

let result: UInt32 = (bit \| (bit \<\< offset1) \| (bit \<\< offset2) \| (bit \<\< offset3))

Yeah, that is indeed strange: https://imgur.com/a/k5HrRiq. I copy-pasted the code into Playgrounds as well, but no error.

Comment by Anders Kierulf (JIRA)

Do you set -Xfrontend -warn-long-expression-type-checking=100 in Other Swift Flags? I'm not seeing an error, just the slow type-check warning.

Yes, I'd expect the result to be the same in this case, with all the types being UInt32. Sorry, I was thinking of the more general case where someone mixes types, but in practice you'll end up with the same behavior here.