-ddump-deriv doesn't dump failed newtype-deriving
When I say
{-# LANGUAGE GeneralizedNewtypeDeriving, TypeFamilies #-}
{-# OPTIONS_GHC -ddump-deriv #-}
type family F a
type instance F Int = Bool
class C a where
meth :: a -> F a
instance C Int where
meth = (> 0)
newtype Age = MkAge Int
deriving C
I get an error (which I should), but I don't get the derived C
instance, as requested by -ddump-deriv
. The output should include this helpful information.
Trac metadata
Trac field | Value |
---|---|
Version | 7.8.2 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |