#include "HsVersions.h"
-import HsSyn ( HsDecl(..), RuleDecl(..), RuleBndr(..), HsTyVarBndr(..) )
-import CoreSyn ( CoreRule(..) )
-import RnHsSyn ( RenamedHsDecl )
-import TcHsSyn ( TypecheckedRuleDecl, mkHsLet )
-import TcMonad
-import TcSimplify ( tcSimplifyToDicts, tcSimplifyAndCheck )
-import TcType ( zonkTcTypes, zonkTcTyVarToTyVar, newTyVarTy )
-import TcIfaceSig ( tcCoreExpr, tcCoreLamBndrs, tcVar )
-import TcMonoType ( kcTyVarScope, kcHsSigType, tcHsSigType, newSigTyVars, checkSigTyVars )
-import TcExpr ( tcExpr )
-import TcEnv ( tcExtendLocalValEnv, newLocalId,
- tcExtendTyVarEnv
- )
-import Inst ( LIE, emptyLIE, plusLIEs, instToId )
-import Id ( idType, idName, mkVanillaId )
-import VarSet
-import Type ( tyVarsOfTypes, openTypeKind )
-import Bag ( bagToList )
+import HsSyn ( RuleDecl(..), LRuleDecl, RuleBndr(..), mkHsDictLet )
+import TcRnMonad
+import TcSimplify ( tcSimplifyToDicts, tcSimplifyInferCheck )
+import TcMType ( newTyFlexiVarTy, zonkQuantifiedTyVar )
+import TcType ( tyVarsOfTypes, openTypeKind )
+import TcHsType ( UserTypeCtxt(..), tcHsPatSigType )
+import TcExpr ( tcCheckRho )
+import TcEnv ( tcExtendIdEnv, tcExtendTyVarEnv )
+import Inst ( instToId )
+import Id ( idType, mkLocalId )
+import Name ( Name )
+import SrcLoc ( noLoc, unLoc )
import Outputable
-import Util
\end{code}
\begin{code}
-tcRules :: [RenamedHsDecl] -> TcM s (LIE, [TypecheckedRuleDecl])
-tcRules decls = mapAndUnzipTc tcRule [rule | RuleD rule <- decls] `thenTc` \ (lies, rules) ->
- returnTc (plusLIEs lies, rules)
-
-tcRule (IfaceRule name vars fun args rhs src_loc)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxt (ruleCtxt name) $
- tcVar fun `thenTc` \ fun' ->
- tcCoreLamBndrs vars $ \ vars' ->
- mapTc tcCoreExpr args `thenTc` \ args' ->
- tcCoreExpr rhs `thenTc` \ rhs' ->
- returnTc (emptyLIE, IfaceRuleOut fun' (Rule name vars' args' rhs'))
-
-tcRule (IfaceRuleOut fun rule)
- = tcVar fun `thenTc` \ fun' ->
- returnTc (emptyLIE, IfaceRuleOut fun' rule)
-
-tcRule (HsRule name sig_tvs vars lhs rhs src_loc)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxt (ruleCtxt name) $
- newTyVarTy openTypeKind `thenNF_Tc` \ rule_ty ->
+tcRules :: [LRuleDecl Name] -> TcM [LRuleDecl TcId]
+tcRules decls = mappM (wrapLocM tcRule) decls
+
+tcRule :: RuleDecl Name -> TcM (RuleDecl TcId)
+tcRule (HsRule name act vars lhs rhs)
+ = addErrCtxt (ruleCtxt name) $
+ traceTc (ptext SLIT("---- Rule ------")
+ <+> ppr name) `thenM_`
+ newTyFlexiVarTy openTypeKind `thenM` \ rule_ty ->
-- Deal with the tyvars mentioned in signatures
- -- Yuk to the UserTyVar
- kcTyVarScope (map UserTyVar sig_tvs)
- (mapTc_ kcHsSigType sig_tys) `thenTc` \ sig_tv_kinds ->
- newSigTyVars sig_tv_kinds `thenNF_Tc` \ sig_tyvars ->
- tcExtendTyVarEnv sig_tyvars (
-
- -- Ditto forall'd variables
- mapNF_Tc new_id vars `thenNF_Tc` \ ids ->
- tcExtendLocalValEnv [(idName id, id) | id <- ids] $
-
+ tcRuleBndrs vars (\ ids ->
-- Now LHS and RHS
- tcExpr lhs rule_ty `thenTc` \ (lhs', lhs_lie) ->
- tcExpr rhs rule_ty `thenTc` \ (rhs', rhs_lie) ->
-
- returnTc (ids, lhs', rhs', lhs_lie, rhs_lie)
- ) `thenTc` \ (ids, lhs', rhs', lhs_lie, rhs_lie) ->
+ 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) ->
-- Check that LHS has no overloading at all
- tcSimplifyToDicts lhs_lie `thenTc` \ (lhs_dicts, lhs_binds) ->
- checkSigTyVars sig_tyvars emptyVarSet `thenTc_`
+ getLIE (tcSimplifyToDicts lhs_lie) `thenM` \ (lhs_binds, lhs_dicts) ->
-- Gather the template variables and tyvars
let
- tpl_ids = map instToId (bagToList lhs_dicts) ++ ids
+ tpl_ids = map instToId lhs_dicts ++ ids
-- IMPORTANT! We *quantify* over any dicts that appear in the LHS
-- Reason:
-- b) We'd like to make available the dictionaries bound
-- on the LHS in the RHS, so quantifying over them is good
-- See the 'lhs_dicts' in tcSimplifyAndCheck for the RHS
- in
-
- -- Gather type variables to quantify over
- -- and turn them into real TyVars (just as in TcBinds.tcBindWithSigs)
- zonkTcTypes (rule_ty : map idType tpl_ids) `thenNF_Tc` \ zonked_tys ->
- mapTc zonkTcTyVarToTyVar (varSetElems (tyVarsOfTypes zonked_tys)) `thenTc` \ tvs ->
+ -- We initially quantify over any tyvars free in *either* the rule
+ -- *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))
+ --
+ -- 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)
+ in
-- RHS can be a bit more lenient. In particular,
-- we let constant dictionaries etc float outwards
- tcSimplifyAndCheck (text "tcRule") (mkVarSet tvs)
- lhs_dicts rhs_lie `thenTc` \ (lie', rhs_binds) ->
-
- returnTc (lie', HsRule name tvs
- (map RuleBndr tpl_ids) -- yuk
- (mkHsLet lhs_binds lhs')
- (mkHsLet rhs_binds rhs')
- src_loc)
+ --
+ -- NB: tcSimplifyInferCheck zonks the forall_tvs, and
+ -- knocks out any that are constrained by the environment
+ 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_tvs2 ++ tpl_ids)) -- yuk
+ (mkHsDictLet lhs_binds lhs')
+ (mkHsDictLet rhs_binds rhs'))
where
- sig_tys = [t | RuleBndrSig _ t <- vars]
- new_id (RuleBndr var) = newTyVarTy openTypeKind `thenNF_Tc` \ ty ->
- returnNF_Tc (mkVanillaId var ty)
- new_id (RuleBndrSig var rn_ty) = tcHsSigType rn_ty `thenTc` \ ty ->
- returnNF_Tc (mkVanillaId var ty)
+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 (ptext name)
+ doubleQuotes (ftext name)
\end{code}
+
+
+
+