Re: unsafePerformIO safety.

Lennart Augustsson wrote:

I wouldn't like if unsafePerformIO could never be inlined, sometimes you want it inlined for performance. And not all uses are hacky, it's just that when I use it, then burden is on me to convince myself that it is safe.

unsafePerformIO is currently not inlined - there's a NOINLINE pragma on its definition in GHC.IOBase, and some comments in there to explain why. You're right that sometimes you really want it to be inlined - this is why there's a function called inlinePerformIO in Data.ByteString.Base, for example. You'd better really know what you're doing before using that one, though :-) Cheers, Simon