T7437.hs:14:13: error:
• The default type signature for put:
forall t. (Generic t, GPut (Rep t)) => t -> [()]
does not match its corresponding non-default type signature
• When checking the class method:
put :: forall a. Put a => a -> [()]
In the class declaration for ‘Put’
T7437.hs:14:13: error:
• Could not deduce (Put a0)
from the context: (Put a, Generic t, GPut (Rep t))
bound by the type signature for:
put :: forall a t. (Put a, Generic t, GPut (Rep t)) => t -> [()]
at T7437.hs:14:13-15
The type variable ‘a0’ is ambiguous
• In the ambiguity check for ‘put’
To defer the ambiguity check to use sites, enable AllowAmbiguousTypes
When checking the class method: put :: forall a. Put a => a -> [()]
In the class declaration for ‘Put’