#include "HsVersions.h"
-import HsSyn ( RuleDecl(..), RuleBndr(..), HsExpr(..), collectRuleBndrSigTys )
+import HsSyn ( RuleDecl(..), RuleBndr(..), collectRuleBndrSigTys )
import CoreSyn ( CoreRule(..) )
import RnHsSyn ( RenamedRuleDecl )
-import TcHsSyn ( TypecheckedRuleDecl, TcExpr, mkHsLet )
+import TcHsSyn ( TypecheckedRuleDecl, mkHsLet )
import TcRnMonad
import TcSimplify ( tcSimplifyToDicts, tcSimplifyInferCheck )
import TcMType ( newTyVarTy )
-import TcType ( TcTyVarSet, tyVarsOfTypes, tyVarsOfType, openTypeKind )
+import TcType ( tyVarsOfTypes, openTypeKind )
import TcIfaceSig ( tcCoreExpr, tcCoreLamBndrs, tcVar )
import TcMonoType ( tcHsSigType, UserTypeCtxt(..), tcAddScopedTyVars )
import TcExpr ( tcMonoExpr )
import TcEnv ( tcExtendLocalValEnv )
import Inst ( instToId )
import Id ( idType, mkLocalId )
-import VarSet
import Outputable
\end{code}
-- RULE: forall v. fst (ss v) = fst v
-- The type of the rhs of the rule is just a, but v::(a,(b,c))
--
- -- We also need to get the free tyvars of the LHS; see notes
- -- below with ruleLhsTvs.
+ -- We also need to get the free tyvars of the LHS; but we do that
+ -- during zonking (see TcHsSyn.zonkRule)
--
forall_tvs = tyVarsOfTypes (rule_ty : map idType tpl_ids)
- `unionVarSet`
- ruleLhsTvs lhs'
in
-- RHS can be a bit more lenient. In particular,
-- we let constant dictionaries etc float outwards
new_id (RuleBndrSig var rn_ty) = tcHsSigType (RuleSigCtxt var) rn_ty `thenM` \ ty ->
returnM (mkLocalId var ty)
-ruleLhsTvs :: TcExpr -> TcTyVarSet
--- We need to gather the type variables mentioned on the LHS so we can
--- quantify over them. Example:
--- data T a = C
---
--- foo :: T a -> Int
--- foo C = 1
---
--- {-# RULES "myrule" foo C = 1 #-}
---
--- After type checking the LHS becomes (foo a (C a))
--- and we do not want to zap the unbound tyvar 'a' to (), because
--- that limits the applicability of the rule. Instead, we
--- want to quantify over it!
---
--- Fortunately the form of the LHS is pretty limited (see RnSource.validRuleLhs)
--- so we don't need to deal with the whole of HsSyn.
---
--- Uh oh! validRuleLhs only checks the function part of rule LHSs!
-
-ruleLhsTvs (HsPar e) = ruleLhsTvs e
-ruleLhsTvs (HsLit e) = emptyVarSet
-ruleLhsTvs (HsOverLit e) = emptyVarSet
-ruleLhsTvs (HsVar v) = emptyVarSet -- I don't think we need the tyvars of the Id
-
-ruleLhsTvs (OpApp e1 op _ e2) = ruleLhsTvs e1 `unionVarSet` ruleLhsTvs op
- `unionVarSet` ruleLhsTvs e2
-ruleLhsTvs (HsApp e1 e2) = ruleLhsTvs e1 `unionVarSet` ruleLhsTvs e2
-ruleLhsTvs (TyApp e1 tys) = ruleLhsTvs e1 `unionVarSet` tyVarsOfTypes tys
-ruleLhsTvs (DictApp e ds) = ruleLhsTvs e
-ruleLhsTvs (NegApp e _) = ruleLhsTvs e
-ruleLhsTvs (ExplicitList ty es) = tyVarsOfType ty `unionVarSet` ruleLhsTvs_s es
-ruleLhsTvs (ExplicitTuple es _) = ruleLhsTvs_s es
-
--- Type abstractions can occur in rules like
--- "foldr k z (build g) = g k z"
-ruleLhsTvs (TyLam tvs e) = ruleLhsTvs e `delVarSetList` tvs
-ruleLhsTvs (DictLam ids e) = ruleLhsTvs e
-ruleLhsTvs e = pprPanic "ruleLhsTvs" (ppr e)
-
-ruleLhsTvs_s es = foldr (unionVarSet . ruleLhsTvs) emptyVarSet es
-
ruleCtxt name = ptext SLIT("When checking the transformation rule") <+>
doubleQuotes (ftext name)
\end{code}