#include "HsVersions.h"
-import HsSyn ( RuleDecl(..), LRuleDecl, RuleBndr(..), collectRuleBndrSigTys, mkHsLet )
+import HsSyn ( RuleDecl(..), LRuleDecl, RuleBndr(..), mkHsDictLet )
import TcRnMonad
import TcSimplify ( tcSimplifyToDicts, tcSimplifyInferCheck )
-import TcMType ( newTyVarTy )
+import TcMType ( newTyFlexiVarTy, zonkQuantifiedTyVar )
import TcType ( tyVarsOfTypes, openTypeKind )
-import TcHsType ( tcHsSigType, UserTypeCtxt(..), tcAddScopedTyVars )
+import TcHsType ( UserTypeCtxt(..), tcHsPatSigType )
import TcExpr ( tcCheckRho )
-import TcEnv ( tcExtendLocalValEnv )
+import TcEnv ( tcExtendIdEnv, tcExtendTyVarEnv )
import Inst ( instToId )
import Id ( idType, mkLocalId )
import Name ( Name )
= addErrCtxt (ruleCtxt name) $
traceTc (ptext SLIT("---- Rule ------")
<+> ppr name) `thenM_`
- newTyVarTy openTypeKind `thenM` \ rule_ty ->
+ newTyFlexiVarTy openTypeKind `thenM` \ rule_ty ->
-- Deal with the tyvars mentioned in signatures
- tcAddScopedTyVars (collectRuleBndrSigTys vars) (
-
- -- Ditto forall'd variables
- mappM new_id vars `thenM` \ ids ->
- tcExtendLocalValEnv ids $
-
+ tcRuleBndrs vars (\ ids ->
-- Now LHS and RHS
getLIE (tcCheckRho lhs rule_ty) `thenM` \ (lhs', lhs_lie) ->
getLIE (tcCheckRho rhs rule_ty) `thenM` \ (rhs', rhs_lie) ->
-
returnM (ids, lhs', rhs', lhs_lie, rhs_lie)
) `thenM` \ (ids, lhs', rhs', lhs_lie, rhs_lie) ->
-- See the 'lhs_dicts' in tcSimplifyAndCheck for the RHS
-- We initially quantify over any tyvars free in *either* the rule
- -- *or* the bound variables. The latter is important. Consider
+ -- *or* the bound variables. The latter is important. Consider
-- ss (x,(y,z)) = (x,z)
-- RULE: forall v. fst (ss v) = fst v
-- The type of the rhs of the rule is just a, but v::(a,(b,c))
tcSimplifyInferCheck (text "tcRule")
forall_tvs
lhs_dicts rhs_lie `thenM` \ (forall_tvs1, rhs_binds) ->
+ mappM zonkQuantifiedTyVar forall_tvs1 `thenM` \ forall_tvs2 ->
+ -- This zonk is exactly the same as the one in TcBinds.tcBindWithSigs
returnM (HsRule name act
- (map (RuleBndr . noLoc) (forall_tvs1 ++ tpl_ids)) -- yuk
- (mkHsLet lhs_binds lhs')
- (mkHsLet rhs_binds rhs'))
+ (map (RuleBndr . noLoc) (forall_tvs2 ++ tpl_ids)) -- yuk
+ (mkHsDictLet lhs_binds lhs')
+ (mkHsDictLet rhs_binds rhs'))
where
- new_id (RuleBndr var) = newTyVarTy openTypeKind `thenM` \ ty ->
- returnM (mkLocalId (unLoc var) ty)
- new_id (RuleBndrSig var rn_ty) = tcHsSigType (RuleSigCtxt nl_var) rn_ty `thenM` \ ty ->
- returnM (mkLocalId nl_var ty)
- where
- nl_var = unLoc var
+
+tcRuleBndrs [] thing_inside = thing_inside []
+tcRuleBndrs (RuleBndr var : vars) thing_inside
+ = do { ty <- newTyFlexiVarTy openTypeKind
+ ; let id = mkLocalId (unLoc var) ty
+ ; tcExtendIdEnv [id] $
+ tcRuleBndrs vars (\ids -> thing_inside (id:ids)) }
+tcRuleBndrs (RuleBndrSig var rn_ty : vars) thing_inside
+ = do { (tyvars, ty) <- tcHsPatSigType (RuleSigCtxt (unLoc var)) rn_ty
+ ; let id = mkLocalId (unLoc var) ty
+ ; tcExtendTyVarEnv tyvars $
+ tcExtendIdEnv [id] $
+ tcRuleBndrs vars (\ids -> thing_inside (id:ids)) }
ruleCtxt name = ptext SLIT("When checking the transformation rule") <+>
doubleQuotes (ftext name)