#include "HsVersions.h"
-import HsSyn ( RuleDecl(..), RuleBndr(..), HsExpr(..), collectRuleBndrSigTys )
-import CoreSyn ( CoreRule(..) )
-import RnHsSyn ( RenamedRuleDecl )
-import TcHsSyn ( TypecheckedRuleDecl, TcExpr, mkHsLet )
+import HsSyn ( RuleDecl(..), LRuleDecl, RuleBndr(..), mkHsLet )
import TcRnMonad
import TcSimplify ( tcSimplifyToDicts, tcSimplifyInferCheck )
-import TcMType ( newTyVarTy )
-import TcType ( TcTyVarSet, tyVarsOfTypes, openTypeKind )
-import TcIfaceSig ( tcCoreExpr, tcCoreLamBndrs, tcVar )
-import TcMonoType ( tcHsSigType, UserTypeCtxt(..), tcAddScopedTyVars )
-import TcExpr ( tcMonoExpr )
-import TcEnv ( tcExtendLocalValEnv )
+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 VarSet
+import Name ( Name )
+import SrcLoc ( noLoc, unLoc )
import Outputable
\end{code}
\begin{code}
-tcRules :: [RenamedRuleDecl] -> TcM [TypecheckedRuleDecl]
-tcRules decls = mappM tcRule decls
-
-tcRule :: RenamedRuleDecl -> TcM TypecheckedRuleDecl
-tcRule (IfaceRule name act vars fun args rhs src_loc)
- = addSrcLoc src_loc $
- addErrCtxt (ruleCtxt name) $
- tcVar fun `thenM` \ fun' ->
- tcCoreLamBndrs vars $ \ vars' ->
- mappM tcCoreExpr args `thenM` \ args' ->
- tcCoreExpr rhs `thenM` \ rhs' ->
- returnM (IfaceRuleOut fun' (Rule name act vars' args' rhs'))
-
-tcRule (IfaceRuleOut fun rule) -- Built-in rules come this way
- = tcVar fun `thenM` \ fun' ->
- returnM (IfaceRuleOut fun' rule)
-
-tcRule (HsRule name act vars lhs rhs src_loc)
- = addSrcLoc src_loc $
- addErrCtxt (ruleCtxt name) $
- newTyVarTy openTypeKind `thenM` \ rule_ty ->
+tcRules :: [LRuleDecl Name] -> TcM [LRuleDecl TcId]
+tcRules decls = mappM (wrapLocM tcRule) decls
- -- Deal with the tyvars mentioned in signatures
- tcAddScopedTyVars (collectRuleBndrSigTys vars) (
+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 ->
- -- Ditto forall'd variables
- mappM new_id vars `thenM` \ ids ->
- tcExtendLocalValEnv ids $
-
+ -- Deal with the tyvars mentioned in signatures
+ tcRuleBndrs vars (\ ids ->
-- Now LHS and RHS
- getLIE (tcMonoExpr lhs rule_ty) `thenM` \ (lhs', lhs_lie) ->
- getLIE (tcMonoExpr rhs rule_ty) `thenM` \ (rhs', 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) ->
-- 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))
--
- -- 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
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 (forall_tvs1 ++ tpl_ids)) -- yuk
+ (map (RuleBndr . noLoc) (forall_tvs2 ++ tpl_ids)) -- yuk
(mkHsLet lhs_binds lhs')
- (mkHsLet rhs_binds rhs')
- src_loc)
+ (mkHsLet rhs_binds rhs'))
where
- new_id (RuleBndr var) = newTyVarTy openTypeKind `thenM` \ ty ->
- returnM (mkLocalId var ty)
- 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.
---
-ruleLhsTvs (OpApp e1 op _ e2)
- = ruleLhsTvs e1 `unionVarSet` ruleLhsTvs op `unionVarSet` ruleLhsTvs e2
-ruleLhsTvs (HsApp e1 e2)
- = ruleLhsTvs e1 `unionVarSet` ruleLhsTvs e2
-ruleLhsTvs (HsVar v) = emptyVarSet -- I don't think we need the tyvars of the Id
-ruleLhsTvs (TyApp e1 tys)
- = ruleLhsTvs e1 `unionVarSet` tyVarsOfTypes tys
-ruleLhsTvs e = pprPanic "ruleLhsTvs" (ppr e)
+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)
projects / ghc-hetmet.git / blobdiff