id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
3954,Contexts on empty data decls falsely rejected,ksf,,"HList uses EmptyDataDecls and contains

{{{
data HNat x => Label x ns desc 
}}}

which fails with 

{{{ 
Data/HList/Label3.hs:37:0:
    No context is allowed on a GADT-style data declaration
    (You can put a context on each contructor, though.) 
}}}

, regressing from 6.10.

My crystal ball tells me someone has been simplifying the implementation of EmptyDataDecls to be GADTs without {{{where}}}, and missed the corner case.",bug,closed,normal,,Compiler (Type checker),6.12.1,duplicate,,,Unknown/Multiple,Unknown/Multiple,GHC rejects valid program,,,,,