\section[TcRules]{Typechecking transformation rules}
\begin{code}
-module TcRules ( tcRules ) where
+module TcRules ( tcIfaceRules, tcSourceRules ) where
#include "HsVersions.h"
-import HsSyn ( HsDecl(..), RuleDecl(..), RuleBndr(..), HsTyVarBndr(..) )
+import HsSyn ( RuleDecl(..), RuleBndr(..) )
import CoreSyn ( CoreRule(..) )
-import RnHsSyn ( RenamedHsDecl )
+import RnHsSyn ( RenamedRuleDecl )
+import HscTypes ( PackageRuleBase )
import TcHsSyn ( TypecheckedRuleDecl, mkHsLet )
import TcMonad
-import TcSimplify ( tcSimplifyToDicts, tcSimplifyAndCheck )
-import TcType ( zonkTcTypes, zonkTcTyVarToTyVar, newTyVarTy )
-import TcIfaceSig ( tcCoreExpr, tcCoreLamBndrs, tcVar )
-import TcMonoType ( kcHsSigType, tcHsSigType, tcTyVars, checkSigTyVars )
+import TcSimplify ( tcSimplifyToDicts, tcSimplifyInferCheck )
+import TcMType ( newTyVarTy )
+import TcType ( tyVarsOfTypes, openTypeKind )
+import TcIfaceSig ( tcCoreExpr, tcCoreLamBndrs, tcVar, tcDelay )
+import TcMonoType ( kcHsSigTypes, tcHsSigType, UserTypeCtxt(..), tcScopedTyVars )
import TcExpr ( tcExpr )
-import TcEnv ( tcExtendLocalValEnv, tcExtendTyVarEnv )
-import Inst ( LIE, emptyLIE, plusLIEs, instToId )
-import Id ( idType, idName, mkVanillaId )
-import VarSet
-import Type ( tyVarsOfTypes, openTypeKind )
-import Bag ( bagToList )
+import TcEnv ( RecTcEnv, tcExtendLocalValEnv, isLocalThing )
+import Rules ( extendRuleBase )
+import Inst ( LIE, plusLIEs, instToId )
+import Id ( idName, idType, mkLocalId )
+import Module ( Module )
+import List ( partition )
import Outputable
\end{code}
\begin{code}
-tcRules :: [RenamedHsDecl] -> TcM (LIE, [TypecheckedRuleDecl])
-tcRules decls = mapAndUnzipTc tcRule [rule | RuleD rule <- decls] `thenTc` \ (lies, rules) ->
- returnTc (plusLIEs lies, rules)
+tcIfaceRules :: RecTcEnv -> PackageRuleBase -> Module -> [RenamedRuleDecl]
+ -> TcM (PackageRuleBase, [TypecheckedRuleDecl])
+tcIfaceRules unf_env pkg_rule_base mod decls
+ = tcDelay unf_env doc [] (
+ -- We need the recursive env because the built-in rules show up as
+ -- IfaceOut rules, sot they get typechecked by tcIfaceRules
+ mapTc tcIfaceRule decls
+ ) `thenTc` \ new_rules ->
+ let
+ (local_rules, imported_rules) = partition is_local new_rules
+ new_rule_base = foldl add pkg_rule_base imported_rules
+ in
+ returnTc (new_rule_base, local_rules)
+ where
+ doc = text "tcIfaceRules"
+ add rule_base (IfaceRuleOut id rule) = extendRuleBase rule_base (id, rule)
+
+ -- When relinking this module from its interface-file decls
+ -- we'll have IfaceRules that are in fact local to this module
+ is_local (IfaceRuleOut n _) = isLocalThing mod n
+ is_local other = True
-tcRule (IfaceRule name vars fun args rhs src_loc)
+tcIfaceRule :: RenamedRuleDecl -> TcM TypecheckedRuleDecl
+ -- No zonking necessary!
+tcIfaceRule (IfaceRule name act 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'))
+ returnTc (IfaceRuleOut fun' (Rule name act vars' args' rhs'))
-tcRule (IfaceRuleOut fun rule)
+tcIfaceRule (IfaceRuleOut fun rule) -- Built-in rules come this way
= tcVar fun `thenTc` \ fun' ->
- returnTc (emptyLIE, IfaceRuleOut fun' rule)
+ returnTc (IfaceRuleOut fun' rule)
-tcRule (HsRule name sig_tvs vars lhs rhs src_loc)
+tcSourceRules :: [RenamedRuleDecl] -> TcM (LIE, [TypecheckedRuleDecl])
+tcSourceRules decls
+ = mapAndUnzipTc tcSourceRule decls `thenTc` \ (lies, decls') ->
+ returnTc (plusLIEs lies, decls')
+
+tcSourceRule (HsRule name act sig_tvs vars lhs rhs src_loc)
= tcAddSrcLoc src_loc $
tcAddErrCtxt (ruleCtxt name) $
newTyVarTy openTypeKind `thenNF_Tc` \ rule_ty ->
-- Deal with the tyvars mentioned in signatures
- tcTyVars sig_tvs (mapTc_ kcHsSigType sig_tys) `thenTc` \ sig_tyvars ->
- tcExtendTyVarEnv sig_tyvars (
+ tcScopedTyVars sig_tvs (kcHsSigTypes sig_tys) (
-- Ditto forall'd variables
mapNF_Tc new_id vars `thenNF_Tc` \ ids ->
tcExpr lhs rule_ty `thenTc` \ (lhs', lhs_lie) ->
tcExpr rhs rule_ty `thenTc` \ (rhs', rhs_lie) ->
- returnTc (sig_tyvars, ids, lhs', rhs', lhs_lie, rhs_lie)
- ) `thenTc` \ (sig_tyvars, ids, lhs', rhs', lhs_lie, rhs_lie) ->
+ returnTc (ids, lhs', rhs', lhs_lie, rhs_lie)
+ ) `thenTc` \ (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_`
+ tcSimplifyToDicts lhs_lie `thenTc` \ (lhs_dicts, lhs_binds) ->
-- 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))
+ --
+ -- It's still conceivable that there may be type variables mentioned
+ -- in the LHS, but not in the type of the lhs, nor in the binders.
+ -- They'll get zapped to (), but that's over-constraining really.
+ -- Let's see if we get a problem.
+ 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) ->
+ --
+ --
+ tcSimplifyInferCheck (text "tcRule")
+ forall_tvs
+ lhs_dicts rhs_lie `thenTc` \ (forall_tvs1, lie', rhs_binds) ->
- returnTc (lie', HsRule name tvs
+ returnTc (lie', HsRule name act forall_tvs1
(map RuleBndr tpl_ids) -- yuk
(mkHsLet lhs_binds lhs')
(mkHsLet 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)
+ new_id (RuleBndr var) = newTyVarTy openTypeKind `thenNF_Tc` \ ty ->
+ returnNF_Tc (mkLocalId var ty)
+ new_id (RuleBndrSig var rn_ty) = tcHsSigType (RuleSigCtxt var) rn_ty `thenTc` \ ty ->
+ returnNF_Tc (mkLocalId var ty)
ruleCtxt name = ptext SLIT("When checking the transformation rule") <+>
doubleQuotes (ptext name)
\end{code}
+
+
+
+
projects / ghc-hetmet.git / blobdiff