Comment by mrkeen

If what your saying is true (the type is fixed as an integer), then it's even easier in tfa's case. No inference necessary.

In my code channel is not a string, it's one type of the 31-set of (String, Foo01, Foo02, .., Foo30). So it needs to be inferred via HM.

> If it was a string then it parses very quickly.

"Parses"? I don't think that's the issue. Did you try it?

----- EDIT ------

I made it an Int

  let channel = 11 :: Int

  instance IsString Int where
    fromString = undefined

  instance Semigroup Int where
    (<>) = undefined


  real    0m0.543s
  user    0m0.396s
  sys     0m0.148s