newtype fixes, coercions for non-recursive newtypes now optional

[ghc-hetmet.git] / compiler / typecheck / TcDeriv.lhs

diff --git a/compiler/typecheck/TcDeriv.lhs b/compiler/typecheck/TcDeriv.lhs
index 46e702c..fdf78cf 100644 (file)
--- a/compiler/typecheck/TcDeriv.lhs
+++ b/compiler/typecheck/TcDeriv.lhs
@@ -42,7 +42,8 @@ import NameSet                ( duDefs )
 import Type            ( splitKindFunTys )
 import TyCon           ( tyConTyVars, tyConDataCons, tyConArity, tyConHasGenerics,
                          tyConStupidTheta, isProductTyCon, isDataTyCon, newTyConRhs,
-                         isEnumerationTyCon, isRecursiveTyCon, TyCon
+                         isEnumerationTyCon, isRecursiveTyCon, TyCon, isNewTyCon,
+                          newTyConCo
                        )
 import TcType          ( TcType, ThetaType, mkTyVarTys, mkTyConApp, tcTyConAppTyCon,
                          isUnLiftedType, mkClassPred, tyVarsOfType,
@@ -367,7 +368,7 @@ makeDerivEqns overlap_flag tycl_decls
           traceTc (text "newtype deriving:" <+> ppr tycon <+> ppr rep_tys)     `thenM_`
                   new_dfun_name clas tycon             `thenM` \ dfun_name ->
           returnM (Nothing, Just (InstInfo { iSpec  = mk_inst_spec dfun_name,
-                                             iBinds = NewTypeDerived rep_tys }))
+                                             iBinds = NewTypeDerived (newTyConCo tycon) rep_tys }))
       | std_class gla_exts clas
       = mk_eqn_help gla_exts DataType tycon deriv_tvs clas tys -- Go via bale-out route