[project @ 2002-09-02 16:31:34 by simonpj]

[ghc-hetmet.git] / ghc / compiler / specialise / Specialise.lhs

diff --git a/ghc/compiler/specialise/Specialise.lhs b/ghc/compiler/specialise/Specialise.lhs
index c9ffa0b..56aa638 100644 (file)
--- a/ghc/compiler/specialise/Specialise.lhs
+++ b/ghc/compiler/specialise/Specialise.lhs
@@ -11,7 +11,7 @@ module Specialise ( specProgram ) where
 import CmdLineOpts     ( DynFlags, DynFlag(..) )
 import Id              ( Id, idName, idType, mkUserLocal, idSpecialisation, isDataConWrapId )
 import TcType          ( Type, mkTyVarTy, tcSplitSigmaTy, 
-                         tyVarsOfTypes, tyVarsOfTheta, 
+                         tyVarsOfTypes, tyVarsOfTheta, isClassPred,
                          mkForAllTys, tcCmpType
                        )
 import Subst           ( Subst, mkSubst, substTy, mkSubst, extendSubstList, mkInScopeSet,
@@ -1003,6 +1003,10 @@ callDetailsToList calls = [ (id,tys,dicts)
 
 mkCallUDs subst f args 
   | null theta
+  || not (all isClassPred theta)       
+       -- Only specialise if all overloading is on class params. 
+       -- In ptic, with implicit params, the type args
+       -- *don't* say what the value of the implicit param is!
   || not (spec_tys `lengthIs` n_tyvars)
   || not ( dicts   `lengthIs` n_dicts)
   || maybeToBool (lookupRule (\act -> True) (substInScope subst) f args)