merge issues with new field for FamEqn

[Alan & Kim Zimmerman]

Change the deriving to

deriving instance (DataIdLR pass pass, Data pats, Data rhs)

Unfortunately the LR stuff bleeds through at the moment.

Alan

On 10 November 2017 at 23:12, John Leo <leo at halfaya.org> wrote:

> Hi everyone,
>
> Today I'm trying to merge the latest HEAD into my work on the explicit
> forall proposal, and I'm running into a problem I'd like help with. The
> changes that are affecting me seem to come from the latest Trees that Grow
> checkins.
>
> I had added a field to FamEqn, namely feqn_bndrs:
>
> data FamEqn pass pats rhs
>   = FamEqn
>        { feqn_tycon  :: Located (IdP pass)
>        , feqn_bndrs  :: Maybe [LHsTyVarBndr pass]
>                         -- ^ Explicit user-provided binders
>        , feqn_pats   :: pats
>        , feqn_fixity :: LexicalFixity -- ^ Fixity used in the declaration
>        , feqn_rhs    :: rhs
>        }
>     -- ^
>     --  - 'ApiAnnotation.AnnKeywordId' : 'ApiAnnotation.AnnEqual',
>     --           'ApiAnnotation.AnnForall','ApiAnnotation.AnnDot'
>
>     -- For details on above see note [Api annotations] in ApiAnnotation
> deriving instance (DataId pass, Data pats, Data rhs)
>                 => Data (FamEqn pass pats rhs)
>
> When I try to compile now, I get the following errors that I cannot
> understand.  I assume I need to do something else, but I'm not sure what it
> is, so I'd appreciate any guidance.
>
> compiler/hsSyn/HsDecls.hs:1441:1: error:
>     • Could not deduce (Data (XValBinds pass pass),
>                         Data (XXValBindsLR pass pass))
>         arising from a use of ‘k’
>       from the context: (DataId pass, Data pats, Data rhs)
>         bound by the instance declaration
>         at compiler/hsSyn/HsDecls.hs:(1441,1)-(1442,46)
>     • In the first argument of ‘k’, namely ‘((z FamEqn `k` a1) `k` a2)’
>       In the first argument of ‘k’, namely
>         ‘(((z FamEqn `k` a1) `k` a2) `k` a3)’
>       In the first argument of ‘k’, namely
>         ‘((((z FamEqn `k` a1) `k` a2) `k` a3) `k` a4)’
>       When typechecking the code for ‘gfoldl’
>         in a derived instance for ‘Data (FamEqn pass pats rhs)’:
>         To see the code I am typechecking, use -ddump-deriv
>      |
> 1441 | deriving instance (DataId pass, Data pats, Data rhs)
>      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^...
>
> compiler/hsSyn/HsDecls.hs:1441:1: error:
>     • Could not deduce (Data (XValBinds pass pass),
>                         Data (XXValBindsLR pass pass))
>         arising from a use of ‘k’
>       from the context: (DataId pass, Data pats, Data rhs)
>         bound by the instance declaration
>         at compiler/hsSyn/HsDecls.hs:(1441,1)-(1442,46)
>     • In the first argument of ‘k’, namely ‘(k (k (z FamEqn)))’
>       In the first argument of ‘k’, namely ‘(k (k (k (z FamEqn))))’
>       In the first argument of ‘k’, namely ‘(k (k (k (k (z FamEqn)))))’
>       When typechecking the code for ‘gunfold’
>         in a derived instance for ‘Data (FamEqn pass pats rhs)’:
>         To see the code I am typechecking, use -ddump-deriv
>      |
> 1441 | deriving instance (DataId pass, Data pats, Data rhs)
>      | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> John
>
>
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