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rebindable6.hs:110:17: error:
• Ambiguous type variable ‘t0’ arising from a do statement
prevents the constraint ‘(HasSeq
(IO a -> t0 -> IO b))’ from being solved.
(maybe you haven't applied a function to enough arguments?)
Relevant bindings include
g :: IO (Maybe b) (bound at rebindable6.hs:108:19)
f :: IO a (bound at rebindable6.hs:108:17)
test_do :: IO a -> IO (Maybe b) -> IO b
(bound at rebindable6.hs:108:9)
Probable fix: use a type annotation to specify what ‘t0’ should be.
These potential instance exist:
instance HasSeq (IO a -> IO b -> IO b)
-- Defined at rebindable6.hs:56:18
• In a stmt of a 'do' block: f
In the expression:
do { f;
Just (b :: b) <- g;
return b }
In an equation for ‘test_do’:
test_do f g
= do { f;
Just (b :: b) <- g;
return b }
rebindable6.hs:111:17: error:
• Ambiguous type variable ‘t1’ arising from a do statement
with the failable pattern ‘Just (b :: b)’
prevents the constraint ‘(HasFail
([Prelude.Char] -> t1))’ from being solved.
(maybe you haven't applied a function to enough arguments?)
Probable fix: use a type annotation to specify what ‘t1’ should be.
These potential instance exist:
instance HasFail (String -> IO a)
-- Defined at rebindable6.hs:61:18
• In a stmt of a 'do' block: Just (b :: b) <- g
In the expression:
do { f;
Just (b :: b) <- g;
return b }
In an equation for ‘test_do’:
test_do f g
= do { f;
Just (b :: b) <- g;
return b }
rebindable6.hs:112:17: error:
• Ambiguous type variable ‘t1’ arising from a use of ‘return’
prevents the constraint ‘(HasReturn (b -> t1))’ from being solved.
(maybe you haven't applied a function to enough arguments?)
Relevant bindings include
b :: b (bound at rebindable6.hs:111:23)
g :: IO (Maybe b) (bound at rebindable6.hs:108:19)
test_do :: IO a -> IO (Maybe b) -> IO b
(bound at rebindable6.hs:108:9)
Probable fix: use a type annotation to specify what ‘t1’ should be.
These potential instance exist:
instance HasReturn (a -> IO a) -- Defined at rebindable6.hs:46:18
• In a stmt of a 'do' block: return b
In the expression:
do { f;
Just (b :: b) <- g;
return b }
In an equation for ‘test_do’:
test_do f g
= do { f;
Just (b :: b) <- g;
return b }
|
