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overloadedlistsfail01.hs:5:8: error:
• Ambiguous type variable ‘a0’ arising from a use of ‘print’
prevents the constraint ‘(Show a0)’ from being solved.
Probable fix: use a type annotation to specify what ‘a0’ should be.
These potential instances exist:
instance Show Ordering -- Defined in ‘GHC.Show’
instance Show Integer -- Defined in ‘GHC.Show’
instance Show a => Show (Maybe a) -- Defined in ‘GHC.Show’
...plus 22 others
...plus six instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the expression: print [1]
In an equation for ‘main’: main = print [1]
overloadedlistsfail01.hs:5:14: error:
• Ambiguous type variable ‘a0’ arising from an overloaded list
prevents the constraint ‘(GHC.Exts.IsList a0)’ from being solved.
Probable fix: use a type annotation to specify what ‘a0’ should be.
These potential instances exist:
instance GHC.Exts.IsList [a] -- Defined in ‘GHC.Exts’
...plus two instances involving out-of-scope types
(use -fprint-potential-instances to see them all)
• In the first argument of ‘print’, namely ‘[1]’
In the expression: print [1]
In an equation for ‘main’: main = print [1]
overloadedlistsfail01.hs:5:15: error:
• Ambiguous type variable ‘a0’ arising from the literal ‘1’
prevents the constraint ‘(Num
(GHC.Exts.Item a0))’ from being solved.
Probable fix: use a type annotation to specify what ‘a0’ should be.
These potential instances exist:
instance Num Integer -- Defined in ‘GHC.Num’
instance Num Double -- Defined in ‘GHC.Float’
instance Num Float -- Defined in ‘GHC.Float’
...plus two others
(use -fprint-potential-instances to see them all)
• In the expression: 1
In the first argument of ‘print’, namely ‘[1]’
In the expression: print [1]
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