\section[TcRules]{Typechecking transformation rules}
\begin{code}
-module TcRules ( tcIfaceRules, tcSourceRules ) where
+module TcRules ( tcRules ) where
#include "HsVersions.h"
import HsSyn ( RuleDecl(..), RuleBndr(..), collectRuleBndrSigTys )
import CoreSyn ( CoreRule(..) )
import RnHsSyn ( RenamedRuleDecl )
-import HscTypes ( PackageRuleBase )
import TcHsSyn ( TypecheckedRuleDecl, mkHsLet )
-import TcMonad
+import TcRnMonad
import TcSimplify ( tcSimplifyToDicts, tcSimplifyInferCheck )
import TcMType ( newTyVarTy )
+import TcUnify ( Expected(..) )
import TcType ( tyVarsOfTypes, openTypeKind )
-import TcIfaceSig ( tcCoreExpr, tcCoreLamBndrs, tcVar, tcDelay )
-import TcMonoType ( kcHsSigTypes, tcHsSigType, UserTypeCtxt(..), tcAddScopedTyVars )
-import TcExpr ( tcExpr )
-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 TcIfaceSig ( tcCoreExpr, tcCoreLamBndrs )
+import TcMonoType ( tcHsSigType, UserTypeCtxt(..), tcAddScopedTyVars )
+import TcExpr ( tcCheckRho )
+import TcEnv ( tcExtendLocalValEnv, tcLookupGlobalId, tcLookupId )
+import Inst ( instToId )
+import Id ( idType, mkLocalId )
import Outputable
\end{code}
\begin{code}
-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
-
-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' ->
+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) $
+ tcLookupGlobalId fun `thenM` \ fun' ->
tcCoreLamBndrs vars $ \ vars' ->
- mapTc tcCoreExpr args `thenTc` \ args' ->
- tcCoreExpr rhs `thenTc` \ rhs' ->
- returnTc (IfaceRuleOut fun' (Rule name act vars' args' rhs'))
-
-tcIfaceRule (IfaceRuleOut fun rule) -- Built-in rules come this way
- = tcVar fun `thenTc` \ fun' ->
- returnTc (IfaceRuleOut fun' rule)
-
-tcSourceRules :: [RenamedRuleDecl] -> TcM (LIE, [TypecheckedRuleDecl])
-tcSourceRules decls
- = mapAndUnzipTc tcSourceRule decls `thenTc` \ (lies, decls') ->
- returnTc (plusLIEs lies, decls')
-
-tcSourceRule (HsRule name act vars lhs rhs src_loc)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxt (ruleCtxt name) $
- newTyVarTy openTypeKind `thenNF_Tc` \ rule_ty ->
+ 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, and only built-in rules,
+ -- come this way. Usually IfaceRuleOut is only
+ -- used for the *output* of the type checker
+ = tcLookupId fun `thenM` \ fun' ->
+ -- NB: tcLookupId, not tcLookupGlobalId
+ -- Reason: when compiling GHC.Base, where eqString is defined,
+ -- we'll get the builtin rule for eqString, but eqString
+ -- will be in the *local* type environment.
+ -- Seems like a bit of a hack
+ returnM (IfaceRuleOut fun' rule)
+
+tcRule (HsRule name act vars lhs rhs src_loc)
+ = addSrcLoc src_loc $
+ addErrCtxt (ruleCtxt name) $
+ newTyVarTy openTypeKind `thenM` \ rule_ty ->
-- Deal with the tyvars mentioned in signatures
tcAddScopedTyVars (collectRuleBndrSigTys vars) (
-- Ditto forall'd variables
- mapNF_Tc new_id vars `thenNF_Tc` \ ids ->
- tcExtendLocalValEnv [(idName id, id) | id <- ids] $
+ mappM new_id vars `thenM` \ ids ->
+ tcExtendLocalValEnv ids $
-- Now LHS and RHS
- tcExpr lhs rule_ty `thenTc` \ (lhs', lhs_lie) ->
- tcExpr rhs rule_ty `thenTc` \ (rhs', rhs_lie) ->
+ getLIE (tcCheckRho lhs rule_ty) `thenM` \ (lhs', lhs_lie) ->
+ getLIE (tcCheckRho rhs rule_ty) `thenM` \ (rhs', rhs_lie) ->
- returnTc (ids, lhs', rhs', lhs_lie, rhs_lie)
- ) `thenTc` \ (ids, lhs', rhs', lhs_lie, 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) ->
+ getLIE (tcSimplifyToDicts lhs_lie) `thenM` \ (lhs_binds, lhs_dicts) ->
-- Gather the template variables and tyvars
let
-- 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.
+ -- 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
--
- --
+ -- 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 `thenTc` \ (forall_tvs1, lie', rhs_binds) ->
+ lhs_dicts rhs_lie `thenM` \ (forall_tvs1, rhs_binds) ->
- returnTc (lie', HsRule name act
- (map RuleBndr (forall_tvs1 ++ tpl_ids)) -- yuk
- (mkHsLet lhs_binds lhs')
- (mkHsLet rhs_binds rhs')
- src_loc)
+ returnM (HsRule name act
+ (map RuleBndr (forall_tvs1 ++ tpl_ids)) -- yuk
+ (mkHsLet lhs_binds lhs')
+ (mkHsLet rhs_binds rhs')
+ src_loc)
where
- 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)
+ 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)
ruleCtxt name = ptext SLIT("When checking the transformation rule") <+>
- doubleQuotes (ptext name)
+ doubleQuotes (ftext name)
\end{code}
projects / ghc-hetmet.git / blobdiff