[burntsushi]

You're doing a lot of repeated work though. I was trying to point out this function, which does unification in a generic context, given some function type: https://godoc.org/github.com/BurntSushi/ty#Check ... For example, it reduces a lot of the reflection boiler plate: https://github.com/BurntSushi/ty/blob/master/fun/list.go#L80