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deriving-via-fail5.hs:8:1: error:
• Couldn't match representation of type ‘a’ with that of ‘b’
arising from a use of ‘GHC.Prim.coerce’
‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
GHC.Prim.coerce
@(Int -> Identity b -> ShowS) @(Int -> Foo4 a -> ShowS)
(showsPrec @(Identity b))
In an equation for ‘showsPrec’:
showsPrec
= GHC.Prim.coerce
@(Int -> Identity b -> ShowS) @(Int -> Foo4 a -> ShowS)
(showsPrec @(Identity b))
When typechecking the code for ‘showsPrec’
in a derived instance for ‘Show (Foo4 a)’:
To see the code I am typechecking, use -ddump-deriv
In the instance declaration for ‘Show (Foo4 a)’
• Relevant bindings include
showsPrec :: Int -> Foo4 a -> ShowS
(bound at deriving-via-fail5.hs:8:1)
deriving-via-fail5.hs:8:1: error:
• Couldn't match representation of type ‘a’ with that of ‘b’
arising from a use of ‘GHC.Prim.coerce’
‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
GHC.Prim.coerce
@(Identity b -> String) @(Foo4 a -> String) (show @(Identity b))
In an equation for ‘show’:
show
= GHC.Prim.coerce
@(Identity b -> String) @(Foo4 a -> String) (show @(Identity b))
When typechecking the code for ‘show’
in a derived instance for ‘Show (Foo4 a)’:
To see the code I am typechecking, use -ddump-deriv
In the instance declaration for ‘Show (Foo4 a)’
• Relevant bindings include
show :: Foo4 a -> String (bound at deriving-via-fail5.hs:8:1)
deriving-via-fail5.hs:8:1: error:
• Couldn't match representation of type ‘a’ with that of ‘b’
arising from a use of ‘GHC.Prim.coerce’
‘a’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
‘b’ is a rigid type variable bound by
the instance declaration
at deriving-via-fail5.hs:(8,1)-(9,24)
• In the expression:
GHC.Prim.coerce
@([Identity b] -> ShowS) @([Foo4 a] -> ShowS)
(showList @(Identity b))
In an equation for ‘showList’:
showList
= GHC.Prim.coerce
@([Identity b] -> ShowS) @([Foo4 a] -> ShowS)
(showList @(Identity b))
When typechecking the code for ‘showList’
in a derived instance for ‘Show (Foo4 a)’:
To see the code I am typechecking, use -ddump-deriv
In the instance declaration for ‘Show (Foo4 a)’
• Relevant bindings include
showList :: [Foo4 a] -> ShowS (bound at deriving-via-fail5.hs:8:1)
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