diff options
Diffstat (limited to 'compiler/GHC/HsToCore/Expr.hs')
| -rw-r--r-- | compiler/GHC/HsToCore/Expr.hs | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/compiler/GHC/HsToCore/Expr.hs b/compiler/GHC/HsToCore/Expr.hs index 5feee52901..834be5907d 100644 --- a/compiler/GHC/HsToCore/Expr.hs +++ b/compiler/GHC/HsToCore/Expr.hs @@ -773,23 +773,21 @@ dsHsConLike (PatSynCon ps) | otherwise = pprPanic "dsConLike" (ppr ps) -dsConLike :: ConLike -> [TcTyVar] -> [Scaled Type] -> DsM CoreExpr --- This function desugars ConLikeTc +-- | This function desugars 'ConLikeTc': it eta-expands +-- data constructors to make linear types work. +-- -- See Note [Typechecking data constructors] in GHC.Tc.Gen.Head --- for what is going on here +dsConLike :: ConLike -> [TcTyVar] -> [Scaled Type] -> DsM CoreExpr dsConLike con tvs tys = do { ds_con <- dsHsConLike con ; ids <- newSysLocalsDs tys - -- newSysLocalDs: /can/ be lev-poly; see + -- NB: these 'Id's may be representation-polymorphic; + -- see Wrinkle [Representation-polymorphic lambda] in + -- Note [Typechecking data constructors] in GHC.Tc.Gen.Head. ; return (mkLams tvs $ mkLams ids $ ds_con `mkTyApps` mkTyVarTys tvs - `mkVarApps` drop_stupid ids) } - where - - drop_stupid = dropList (conLikeStupidTheta con) - -- drop_stupid: see Note [Instantiating stupid theta] - -- in GHC.Tc.Gen.Head + `mkVarApps` ids) } {- ************************************************************************ |