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gadt21.hs:21:60: error: [GHC-39999]
• Could not deduce ‘Ord a1’ arising from a use of ‘f’
from the context: a ~ Set a1
bound by a pattern with constructor:
TypeSet :: forall a. Type a -> Type (Set a),
in an equation for ‘withOrdDynExpr’
at gadt21.hs:21:35-43
Possible fix:
add (Ord a1) to the context of the data constructor ‘TypeSet’
• In the first argument of ‘Just’, namely ‘(f e)’
In the expression: Just (f e)
In an equation for ‘withOrdDynExpr’:
withOrdDynExpr (DynExpr e@(Const (TypeSet _) _)) f = Just (f e)
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