Parse error on curried context of instance declaration
Assume we have the following classes:
class C1 a; class C2 a; class C3 a; class C4 a
GHC allows you to write a type with an uncurried context, as in:
foo :: (C1 a, C2 b, C3 c) => a -> b -> c
It also allows you to write a type with a curried context, as in:
foo :: C1 a => C2 b => C3 c => a -> b -> c
However it is not allowed to use this curried style of contexts in instance declarations, as in:
instance C1 a => C2 b => C3 c => C4 (SomeType a b c)
Is this intentional?
Trac metadata
Trac field | Value |
---|---|
Version | 6.12.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
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Blocking | |
CC | |
Operating system | |
Architecture |