#include "HsVersions.h"
-import HsSyn ( HsDecl(..), RuleDecl(..), RuleBndr(..), HsTyVar(..) )
-import HsCore ( UfRuleBody(..) )
-import RnHsSyn ( RenamedHsDecl )
-import TcHsSyn ( TypecheckedRuleDecl, mkHsLet )
-import TcMonad
-import TcSimplify ( tcSimplifyToDicts, tcSimplifyAndCheck )
-import TcType ( zonkTcTypes, newTyVarTy_OpenKind )
-import TcIfaceSig ( tcCoreExpr, tcCoreLamBndrs, tcVar )
-import TcMonoType ( tcHsSigType, tcHsTyVar, 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 )
-import Bag ( bagToList )
+import HsSyn ( RuleDecl(..), LRuleDecl, RuleBndr(..), mkHsDictLet )
+import TcRnMonad
+import TcSimplify ( tcSimplifyToDicts, tcSimplifyInferCheck )
+import TcMType ( newFlexiTyVarTy, zonkQuantifiedTyVar, tcSkolSigTyVars )
+import TcType ( tyVarsOfTypes, openTypeKind, SkolemInfo(..), substTyWith, mkTyVarTys )
+import TcHsType ( UserTypeCtxt(..), tcHsPatSigType )
+import TcExpr ( tcMonoExpr )
+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 (IfaceRuleDecl fun (UfRuleBody name vars 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, IfaceRuleDecl fun' (CoreRuleBody name vars' args' rhs') src_loc)
-
-tcRule (RuleDecl name sig_tvs vars lhs rhs src_loc)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxt (ruleCtxt name) $
- newTyVarTy_OpenKind `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_`
+ newFlexiTyVarTy openTypeKind `thenM` \ rule_ty ->
-- Deal with the tyvars mentioned in signatures
- -- Yuk to the UserTyVar
- mapNF_Tc (tcHsTyVar . UserTyVar) sig_tvs `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 (tcMonoExpr lhs rule_ty) `thenM` \ (lhs', lhs_lie) ->
+ getLIE (tcMonoExpr 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 `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
- zonkTcTypes (rule_ty : map idType tpl_ids) `thenNF_Tc` \ zonked_tys ->
- let
- tpl_tvs = tyVarsOfTypes zonked_tys
+ -- 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") tpl_tvs
- lhs_dicts rhs_lie `thenTc` \ (lie', rhs_binds) ->
-
- returnTc (lie', RuleDecl name (varSetElems tpl_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
- new_id (RuleBndr var) = newTyVarTy_OpenKind `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 <- newFlexiTyVarTy openTypeKind
+ ; let id = mkLocalId (unLoc var) ty
+ ; tcExtendIdEnv [id] $
+ tcRuleBndrs vars (\ids -> thing_inside (id:ids)) }
+tcRuleBndrs (RuleBndrSig var rn_ty : vars) thing_inside
+-- e.g x :: a->a
+-- The tyvar 'a' is brought into scope first, just as if you'd written
+-- a::*, x :: a->a
+ = do { let ctxt = RuleSigCtxt (unLoc var)
+ ; (tyvars, ty) <- tcHsPatSigType ctxt rn_ty
+ ; let skol_tvs = tcSkolSigTyVars (SigSkol ctxt) tyvars
+ id_ty = substTyWith tyvars (mkTyVarTys skol_tvs) ty
+ id = mkLocalId (unLoc var) id_ty
+ ; tcExtendTyVarEnv skol_tvs $
+ 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}
+
+
+
+
projects / ghc-hetmet.git / blobdiff