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T8142.hs:6:18:
Couldn't match type ‘Nu ((,) t0)’ with ‘Nu ((,) t)’
NB: ‘Nu’ is a type function, and may not be injective
The type variable ‘t0’ is ambiguous
Expected type: Nu ((,) t) -> Nu f
Actual type: Nu ((,) t0) -> Nu f0
When checking that ‘h’
has the inferred type ‘forall t (f :: * -> *). Nu ((,) t) -> Nu f’
Probable cause: the inferred type is ambiguous
In an equation for ‘tracer’:
tracer
= h
where
h = (\ (_, b) -> ((outI . fmap h) b)) . out
T8142.hs:6:57:
Could not deduce (Nu ((,) t) ~ f1 (Nu ((,) t)))
from the context (Functor f, Coinductive f)
bound by the type signature for
tracer :: (Functor f, Coinductive f) => (c -> f c) -> c -> f c
at T8142.hs:5:11-64
Expected type: Nu ((,) t) -> (t, f1 (Nu ((,) t)))
Actual type: Nu ((,) t) -> (t, Nu ((,) t))
Relevant bindings include
h :: Nu ((,) t) -> Nu f1 (bound at T8142.hs:6:18)
In the second argument of ‘(.)’, namely ‘out’
In the expression: (\ (_, b) -> ((outI . fmap h) b)) . out
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