Hit an "impossible error" trying to write some set extensions

[ryanprior]

I'm writing a small "set extensions" module and hit a snag.

Sandbox: https://mint-lang.com/sandbox/K2ayJmLpwSd4hA

Code to trigger the "impossible error":

module SetX {
  fun reduce(set : Set(item), initial : memo, function : Function(memo, item, memo)) {
    `#{set}.reduce(#{function}, #{initial})`
  }

  fun intersection(left : Set(item), right : Set(item)) {
    reduce(left, Set.empty, (memo : Set(item), value : item) {
      if(Set.has(left, value) && Set.has(right, value)) {
        Set.add(memo, value)
      } else {
        memo
      }
    })
  }
}

I'm using Mint 0.22.0

[ryanprior]

This may shed light on the origin of the error: changing Set.empty to Set.empty() makes the function work as expected.

[gdotdesign]

Thank you for opening this issue, it helped me track it down what is happening so I was able to add proper error message for it 🙏 Fixed by 4508531