module Main.Excp where
import Main.ErrorCode
import DA.Exception
exception Excp
with
errorCode: ErrorCode
where
message "Excp Exception: " <> show errorCode
This comes from a warning that is not turned on by default, specifically -Wunused-matches (or a slightly different flag that also ends up enabling this one).
It’s a false positive here. this is in implicitly in scope in message (just like for templates) and you’re not using it so you get the warning. I’ll open an issue to fix that.