Thanks Sergiu, I know there was some defaulting, but didn't think much of it beyond that. Special GHCi handling makes sense. Maybe I'll open a ticket just in case this is an unintended effect. Interesting observation about loading it from a file via typing it in. My code is actually a test case for use with the doctest package that I was just running manually to work out. I'm not sure if it does the equivalent of loading it from a file or not. Ultimately I wound up doing the binding via a case statement instead of let. It seems GHCi is okay with that. Cheers! -Tyon On Tue, Apr 18, 2017, 17:01 Sergiu Ivanov <sivanov@colimite.fr <mailto:sivanov@colimite.fr>> wrote: GHCi handles polymorphic types of interactive expressions somewhat differently from the polymorphic types of expressions loaded from files. (I'd be happy if someone could reproduce the explanation which I saw a couple times but which I cannot find any more.)