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gadt13.hs:15:13: error:
• Couldn't match expected type ‘r’
with actual type ‘String -> [Char]’
‘r’ is untouchable
inside the constraints: t ~ Int
bound by a pattern with constructor: I :: Int -> Term Int,
in an equation for ‘shw’
at gadt13.hs:15:6-8
‘r’ is a rigid type variable bound by
the inferred type of shw :: Term t -> r at gadt13.hs:15:1
Possible fix: add a type signature for ‘shw’
• Possible cause: ‘(.)’ is applied to too many arguments
In the expression: ("I " ++) . shows t
In an equation for ‘shw’: shw (I t) = ("I " ++) . shows t
• Relevant bindings include
shw :: Term t -> r (bound at gadt13.hs:15:1)
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