diff options
Diffstat (limited to 'compiler/GHC/Core/DataCon.hs')
| -rw-r--r-- | compiler/GHC/Core/DataCon.hs | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/compiler/GHC/Core/DataCon.hs b/compiler/GHC/Core/DataCon.hs index a9e540769e..f54f42d99d 100644 --- a/compiler/GHC/Core/DataCon.hs +++ b/compiler/GHC/Core/DataCon.hs @@ -1669,13 +1669,25 @@ dataConOtherTheta dc = dcOtherTheta dc -- evidence, after any flattening has been done and without substituting for -- any type variables dataConRepArgTys :: DataCon -> [Scaled Type] -dataConRepArgTys (MkData { dcRep = rep - , dcEqSpec = eq_spec +dataConRepArgTys (MkData { dcRep = rep + , dcEqSpec = eq_spec , dcOtherTheta = theta - , dcOrigArgTys = orig_arg_tys }) + , dcOrigArgTys = orig_arg_tys + , dcRepTyCon = tc }) = case rep of - NoDataConRep -> assert (null eq_spec) $ map unrestricted theta ++ orig_arg_tys DCR { dcr_arg_tys = arg_tys } -> arg_tys + NoDataConRep + | isTypeDataTyCon tc -> assert (null theta) $ + orig_arg_tys + -- `type data` declarations can be GADTs (and hence have an eq_spec) + -- but no wrapper. They cannot have a theta. + -- See Note [Type data declarations] in GHC.Rename.Module + -- You might wonder why we ever call dataConRepArgTys for `type data`; + -- I think it's because of the call in mkDataCon, which in turn feeds + -- into dcRepArity, which in turn is used in mkDataConWorkId. + -- c.f. #23022 + | otherwise -> assert (null eq_spec) $ + map unrestricted theta ++ orig_arg_tys -- | The string @package:module.name@ identifying a constructor, which is attached -- to its info table and used by the GHCi debugger and the heap profiler |