Purescript Eq instance

Eq.purs

module Main where

import Debug.Trace
 
data T = A | B Number
 
instance eqT :: Eq T where
  A == A = true
  (B v1) == (B v2) = v1 == v2
  _ == _ = false
  t1 /= t2 == not (t1 == t2)
 
main = print $ [A, B 123] == [A, B 123]

Output

"Eq.purs" (line 6, column 3):
unexpected UName "A"
expecting no indentation or end of input

Not exactly sure why, but this seem to work better

instance eqT :: Eq T where
  (==)A A = true
  (==) (B v1) (B v2) = v1 == v2
  (== )_ _ = false
  (/=) t1 t2 = not (t1 == t2)

Yes, the compiler doesn't support infix pattern matches right now.