testsuite/tests/typecheck/should_fail/T5095.hs


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{-# LANGUAGE FlexibleInstances, UndecidableInstances #-}

module Test where

instance {-# OVERLAPPABLE #-} Show a => Eq a where
   x == y =  length (show x) == length (show y)

f :: Show a => a -> a -> Bool
f x y = x == y

p = f (3 :: Int) 4