diff options
Diffstat (limited to 'compiler/GHC/Hs')
| -rw-r--r-- | compiler/GHC/Hs/Expr.hs | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/compiler/GHC/Hs/Expr.hs b/compiler/GHC/Hs/Expr.hs index ef8934b831..78b07e54a3 100644 --- a/compiler/GHC/Hs/Expr.hs +++ b/compiler/GHC/Hs/Expr.hs @@ -38,7 +38,6 @@ import GHC.Hs.Binds -- others: import GHC.Tc.Types.Evidence import GHC.Core -import GHC.Types.Id( Id ) import GHC.Types.Name import GHC.Types.Name.Set import GHC.Types.Basic @@ -252,8 +251,10 @@ data HsExpr p -- Turned from HsVar to HsUnboundVar by the -- renamer, when it finds an out-of-scope -- variable or hole. - -- The (XUnboundVar p) field becomes Id - -- after typechecking + -- The (XUnboundVar p) field becomes an HoleExprRef + -- after typechecking; this is where the + -- erroring expression will be written after + -- solving. See Note [Holes] in GHC.Tc.Types.Constraint. | HsConLikeOut (XConLikeOut p) ConLike -- ^ After typechecker only; must be different @@ -608,7 +609,11 @@ type instance XApp (GhcPass _) = NoExtField type instance XUnboundVar GhcPs = NoExtField type instance XUnboundVar GhcRn = NoExtField -type instance XUnboundVar GhcTc = Id +type instance XUnboundVar GhcTc = HoleExprRef + -- We really don't need the whole HoleExprRef; just the IORef EvTerm + -- would be enough. But then deriving a Data instance becomes impossible. + -- Much, much easier just to define HoleExprRef with a Data instance and + -- store the whole structure. type instance XAppTypeE GhcPs = NoExtField type instance XAppTypeE GhcRn = NoExtField |