Ah... now I understand your concern; I should have written
something like:
where K +_t K' denotes the set of constraints from K plus
those from K' that have type variables reachable from t.
instead of:
where K +_t K' denotes the constraint-set obtained by adding from K'
only constraints wi
-- Forwarded message --
From: Carlos Camarao
Date: Fri, Sep 17, 2010 at 12:01 AM
Subject: Re: [Haskell-cafe] Reachable variables exercise
To: Luke Palmer
boolify o has type Boolable a => Bool under the proposal, then
we have ambiguity, type error, right?
In general, consi
I am not totally sure if I understand your proposal correctly, but if
I do, then it has a flaw. Consider:
class Boolable a where
boolify :: a -> Bool
class O a where
o :: a
main = print $ boolify o
It seems like under your proposal this should not be a type error.
B
Hi. Consider for example an expression e0 like:
fst (True,e)
where e is any expression.
e0 should have type Bool IMHO irrespectively of the type of e. In Haskell
this is the case if e's type is monomorphic, or polymorphic, or
constrained and there is a default in the current module that remove
