\section[TcInstDecls]{Typechecking instance declarations}
\begin{code}
-module TcInstDcls ( tcInstDecls1, tcInstDecls2, tcAddDeclCtxt ) where
+module TcInstDcls ( tcInstDecls1, tcIfaceInstDecls1, addInstDFuns,
+ tcInstDecls2, initInstEnv, tcAddDeclCtxt ) where
#include "HsVersions.h"
import CmdLineOpts ( DynFlag(..) )
-import HsSyn ( HsDecl(..), InstDecl(..), TyClDecl(..), HsType(..),
+import HsSyn ( InstDecl(..), TyClDecl(..), HsType(..),
MonoBinds(..), HsExpr(..), HsLit(..), Sig(..), HsTyVarBndr(..),
andMonoBindList, collectMonoBinders,
- isClassDecl, isIfaceInstDecl, toHsType
+ isClassDecl, toHsType
)
-import RnHsSyn ( RenamedHsBinds, RenamedInstDecl, RenamedHsDecl,
+import RnHsSyn ( RenamedHsBinds, RenamedInstDecl,
RenamedMonoBinds, RenamedTyClDecl, RenamedHsType,
extractHsTyVars, maybeGenericMatch
)
import TcHsSyn ( TcMonoBinds, mkHsConApp )
import TcBinds ( tcSpecSigs )
-import TcClassDcl ( tcMethodBind, badMethodErr )
+import TcClassDcl ( tcMethodBind, mkMethodBind, badMethodErr )
import TcMonad
-import TcMType ( tcInstSigType, checkValidTheta, checkValidInstHead, instTypeErr,
+import TcMType ( tcInstType, checkValidTheta, checkValidInstHead, instTypeErr,
UserTypeCtxt(..), SourceTyCtxt(..) )
-import TcType ( mkClassPred, mkTyVarTy, mkTyVarTys, tcSplitForAllTys,
+import TcType ( mkClassPred, mkTyVarTy, tcSplitForAllTys,
tcSplitSigmaTy, getClassPredTys, tcSplitPredTy_maybe,
TyVarDetails(..)
)
import Inst ( InstOrigin(..), newDicts, instToId,
LIE, mkLIE, emptyLIE, plusLIE, plusLIEs )
import TcDeriv ( tcDeriving )
-import TcEnv ( TcEnv, tcExtendGlobalValEnv,
- tcExtendTyVarEnvForMeths, tcLookupId, tcLookupClass,
+import TcEnv ( tcExtendGlobalValEnv, tcExtendLocalValEnv2,
+ tcLookupId, tcLookupClass, tcExtendTyVarEnv2,
InstInfo(..), pprInstInfo, simpleInstInfoTyCon,
simpleInstInfoTy, newDFunName
)
import InstEnv ( InstEnv, extendInstEnv )
import PprType ( pprClassPred )
-import TcMonoType ( tcHsTyVars, kcHsSigType, tcHsType, tcHsSigType )
+import TcMonoType ( tcSigPolyId, tcHsTyVars, kcHsSigType, tcHsType, tcHsSigType )
import TcUnify ( checkSigTyVars )
import TcSimplify ( tcSimplifyCheck )
-import HscTypes ( HomeSymbolTable, DFunId,
- ModDetails(..), PackageInstEnv, PersistentRenamerState
+import HscTypes ( HomeSymbolTable, DFunId, FixityEnv,
+ PersistentCompilerState(..), PersistentRenamerState,
+ ModDetails(..)
)
-import Subst ( substTy, substTheta )
+import Subst ( mkTyVarSubst, substTheta )
import DataCon ( classDataCon )
import Class ( Class, classBigSig )
import Var ( idName, idType )
-import VarSet ( emptyVarSet )
import Id ( setIdLocalExported )
import MkId ( mkDictFunId, unsafeCoerceId, eRROR_ID )
import FunDeps ( checkInstFDs )
import Name ( getSrcLoc )
import NameSet ( unitNameSet, emptyNameSet, nameSetToList )
import TyCon ( TyCon )
-import Subst ( mkTopTyVarSubst, substTheta )
import TysWiredIn ( genericTyCons )
-import Name ( Name )
import SrcLoc ( SrcLoc )
import Unique ( Uniquable(..) )
import Util ( lengthExceeds, isSingleton )
-import BasicTypes ( NewOrData(..), Fixity )
+import BasicTypes ( NewOrData(..) )
import ErrUtils ( dumpIfSet_dyn )
import ListSetOps ( Assoc, emptyAssoc, plusAssoc_C, mapAssoc,
assocElts, extendAssoc_C, equivClassesByUniq, minusList
)
import Maybe ( catMaybes )
-import List ( partition )
import Outputable
\end{code}
Gather up the instance declarations from their various sources
\begin{code}
-tcInstDecls1 :: PackageInstEnv
- -> PersistentRenamerState
- -> HomeSymbolTable -- Contains instances
- -> TcEnv -- Contains IdInfo for dfun ids
- -> (Name -> Maybe Fixity) -- for deriving Show and Read
- -> Module -- Module for deriving
- -> [RenamedHsDecl]
- -> TcM (PackageInstEnv, InstEnv, [InstInfo], RenamedHsBinds)
-
-tcInstDecls1 inst_env0 prs hst unf_env get_fixity this_mod decls
- = let
- inst_decls = [inst_decl | InstD inst_decl <- decls]
- tycl_decls = [decl | TyClD decl <- decls]
- clas_decls = filter isClassDecl tycl_decls
- (imported_inst_ds, local_inst_ds) = partition isIfaceInstDecl inst_decls
- in
+tcInstDecls1 -- Deal with source-code instance decls
+ :: PersistentRenamerState
+ -> InstEnv -- Imported instance envt
+ -> FixityEnv -- for deriving Show and Read
+ -> Module -- Module for deriving
+ -> [RenamedTyClDecl] -- For deriving stuff
+ -> [RenamedInstDecl] -- Source code instance decls
+ -> TcM (InstEnv, -- the full inst env
+ [InstInfo], -- instance decls to process; contains all dfuns
+ -- for this module
+ RenamedHsBinds) -- derived instances
+
+tcInstDecls1 prs inst_env get_fixity this_mod
+ tycl_decls inst_decls
+-- The incoming inst_env includes all the imported instances already
+ = checkNoErrsTc $
+ -- Stop if addInstInfos etc discovers any errors
+ -- (they recover, so that we get more than one error each round)
-- (1) Do the ordinary instance declarations
- mapNF_Tc tcLocalInstDecl1 local_inst_ds `thenNF_Tc` \ local_inst_infos ->
- mapNF_Tc tcImportedInstDecl1 imported_inst_ds `thenNF_Tc` \ imported_dfuns ->
+ mapNF_Tc tcLocalInstDecl1 inst_decls `thenNF_Tc` \ local_inst_infos ->
+ let
+ local_inst_info = catMaybes local_inst_infos
+ clas_decls = filter isClassDecl tycl_decls
+ in
-- (2) Instances from generic class declarations
getGenericInstances clas_decls `thenTc` \ generic_inst_info ->
-- Next, construct the instance environment so far, consisting of
- -- a) cached non-home-package InstEnv (gotten from pcs) pcs_insts pcs
- -- b) imported instance decls (not in the home package) inst_env1
- -- c) other modules in this package (gotten from hst) inst_env2
- -- d) local instance decls inst_env3
- -- e) generic instances inst_env4
- -- The result of (b) replaces the cached InstEnv in the PCS
- let
- local_inst_info = catMaybes local_inst_infos
- hst_dfuns = foldModuleEnv ((++) . md_insts) [] hst
- in
-
--- pprTrace "tcInstDecls" (vcat [ppr imported_dfuns, ppr hst_dfuns]) $
-
- addInstDFuns inst_env0 imported_dfuns `thenNF_Tc` \ inst_env1 ->
- addInstDFuns inst_env1 hst_dfuns `thenNF_Tc` \ inst_env2 ->
- addInstInfos inst_env2 local_inst_info `thenNF_Tc` \ inst_env3 ->
- addInstInfos inst_env3 generic_inst_info `thenNF_Tc` \ inst_env4 ->
+ -- a) imported instance decls (from this module) inst_env1
+ -- b) local instance decls inst_env2
+ -- c) generic instances final_inst_env
+ addInstInfos inst_env local_inst_info `thenNF_Tc` \ inst_env1 ->
+ addInstInfos inst_env1 generic_inst_info `thenNF_Tc` \ inst_env2 ->
-- (3) Compute instances from "deriving" clauses;
-- note that we only do derivings for things in this module;
-- we ignore deriving decls from interfaces!
-- This stuff computes a context for the derived instance decl, so it
-- needs to know about all the instances possible; hence inst_env4
- tcDeriving prs this_mod inst_env4 get_fixity tycl_decls
- `thenTc` \ (deriv_inst_info, deriv_binds) ->
- addInstInfos inst_env4 deriv_inst_info `thenNF_Tc` \ final_inst_env ->
+ tcDeriving prs this_mod inst_env2
+ get_fixity tycl_decls `thenTc` \ (deriv_inst_info, deriv_binds) ->
+ addInstInfos inst_env2 deriv_inst_info `thenNF_Tc` \ final_inst_env ->
- returnTc (inst_env1,
- final_inst_env,
+ returnTc (final_inst_env,
generic_inst_info ++ deriv_inst_info ++ local_inst_info,
deriv_binds)
+initInstEnv :: PersistentCompilerState -> HomeSymbolTable -> NF_TcM InstEnv
+-- Initialise the instance environment from the
+-- persistent compiler state and the home symbol table
+initInstEnv pcs hst
+ = let
+ pkg_inst_env = pcs_insts pcs
+ hst_dfuns = foldModuleEnv ((++) . md_insts) [] hst
+ in
+ addInstDFuns pkg_inst_env hst_dfuns
+
addInstInfos :: InstEnv -> [InstInfo] -> NF_TcM InstEnv
addInstInfos inst_env infos = addInstDFuns inst_env (map iDFunId infos)
\end{code}
\begin{code}
-tcImportedInstDecl1 :: RenamedInstDecl -> NF_TcM DFunId
+tcIfaceInstDecls1 :: [RenamedInstDecl] -> NF_TcM [DFunId]
+tcIfaceInstDecls1 decls = mapNF_Tc tcIfaceInstDecl1 decls
+
+tcIfaceInstDecl1 :: RenamedInstDecl -> NF_TcM DFunId
-- An interface-file instance declaration
-- Should be in scope by now, because we should
-- have sucked in its interface-file definition
-- So it will be replete with its unfolding etc
-tcImportedInstDecl1 decl@(InstDecl poly_ty binds uprags (Just dfun_name) src_loc)
+tcIfaceInstDecl1 decl@(InstDecl poly_ty binds uprags (Just dfun_name) src_loc)
= tcLookupId dfun_name
tcInstDecl2 :: InstInfo -> TcM (LIE, TcMonoBinds)
tcInstDecl2 (NewTypeDerived { iDFunId = dfun_id })
- = tcInstSigType InstTv (idType dfun_id) `thenNF_Tc` \ (inst_tyvars', dfun_theta', inst_head') ->
+ = tcInstType InstTv (idType dfun_id) `thenNF_Tc` \ (inst_tyvars', dfun_theta', inst_head') ->
newDicts InstanceDeclOrigin dfun_theta' `thenNF_Tc` \ rep_dicts ->
let
rep_dict_id = ASSERT( isSingleton rep_dicts )
recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyMonoBinds)) $
tcAddSrcLoc (getSrcLoc dfun_id) $
tcAddErrCtxt (instDeclCtxt (toHsType (idType dfun_id))) $
+ let
+ inst_ty = idType dfun_id
+ (inst_tyvars, _) = tcSplitForAllTys inst_ty
+ -- The tyvars of the instance decl scope over the 'where' part
+ -- Those tyvars are inside the dfun_id's type, which is a bit
+ -- bizarre, but OK so long as you realise it!
+ in
-- Instantiate the instance decl with tc-style type variables
- tcInstSigType InstTv (idType dfun_id) `thenNF_Tc` \ (inst_tyvars', dfun_theta', inst_head') ->
+ tcInstType InstTv inst_ty `thenNF_Tc` \ (inst_tyvars', dfun_theta', inst_head') ->
let
Just pred = tcSplitPredTy_maybe inst_head'
(clas, inst_tys') = getClassPredTys pred
sel_names = [idName sel_id | (sel_id, _) <- op_items]
-- Instantiate the super-class context with inst_tys
- sc_theta' = substTheta (mkTopTyVarSubst class_tyvars inst_tys') sc_theta
+ sc_theta' = substTheta (mkTyVarSubst class_tyvars inst_tys') sc_theta
-- Find any definitions in monobinds that aren't from the class
- bad_bndrs = collectMonoBinders monobinds `minusList` sel_names
- (inst_tyvars, _) = tcSplitForAllTys (idType dfun_id)
- origin = InstanceDeclOrigin
+ bad_bndrs = collectMonoBinders monobinds `minusList` sel_names
+ origin = InstanceDeclOrigin
in
-- Check that all the method bindings come from this class
mapTc (addErrTc . badMethodErr clas) bad_bndrs `thenNF_Tc_`
newDicts origin sc_theta' `thenNF_Tc` \ sc_dicts ->
newDicts origin dfun_theta' `thenNF_Tc` \ dfun_arg_dicts ->
newDicts origin [mkClassPred clas inst_tys'] `thenNF_Tc` \ [this_dict] ->
-
- tcExtendTyVarEnvForMeths inst_tyvars inst_tyvars' (
- -- The type variable from the dict fun actually scope
- -- over the bindings. They were gotten from
- -- the original instance declaration
-
-- Default-method Ids may be mentioned in synthesised RHSs,
-- but they'll already be in the environment.
- mapAndUnzip3Tc (tcMethodBind clas origin inst_tyvars' inst_tys'
- dfun_theta'
- monobinds uprags True)
- op_items
- ) `thenTc` \ (method_binds_s, insts_needed_s, meth_insts) ->
+ mapAndUnzipTc (mkMethodBind origin clas inst_tys' monobinds)
+ op_items `thenTc` \ (meth_insts, meth_infos) ->
- -- Deal with SPECIALISE instance pragmas by making them
- -- look like SPECIALISE pragmas for the dfun
- let
- dfun_prags = [SpecSig (idName dfun_id) ty loc | SpecInstSig ty loc <- uprags]
- in
- tcExtendGlobalValEnv [dfun_id] (
- tcSpecSigs dfun_prags
- ) `thenTc` \ (prag_binds, prag_lie) ->
-
- -- Check the overloading constraints of the methods and superclasses
- let
+ let
-- These insts are in scope; quite a few, eh?
avail_insts = [this_dict] ++
dfun_arg_dicts ++
sc_dicts ++
meth_insts
- methods_lie = plusLIEs insts_needed_s
+ xtve = inst_tyvars `zip` inst_tyvars'
+ tc_meth = tcMethodBind xtve inst_tyvars' dfun_theta' avail_insts
in
+ mapAndUnzipTc tc_meth meth_infos `thenTc` \ (meth_binds_s, meth_lie_s) ->
- -- Simplify the constraints from methods
- tcAddErrCtxt methodCtxt (
- tcSimplifyCheck
- (ptext SLIT("instance declaration context"))
- inst_tyvars'
- avail_insts
- methods_lie
- ) `thenTc` \ (const_lie1, lie_binds1) ->
-
-- Figure out bindings for the superclass context
- tcAddErrCtxt superClassCtxt (
- tcSimplifyCheck
- (ptext SLIT("instance declaration context"))
+ tcAddErrCtxt superClassCtxt $
+ tcSimplifyCheck
+ (ptext SLIT("instance declaration superclass context"))
inst_tyvars'
dfun_arg_dicts -- NB! Don't include this_dict here, else the sc_dicts
-- get bound by just selecting from this_dict!!
(mkLIE sc_dicts)
- ) `thenTc` \ (const_lie2, lie_binds2) ->
+ `thenTc` \ (sc_lie, sc_binds) ->
+ -- It's possible that the superclass stuff might have done unification
+ checkSigTyVars inst_tyvars' `thenNF_Tc` \ zonked_inst_tyvars ->
- checkSigTyVars inst_tyvars' emptyVarSet `thenNF_Tc` \ zonked_inst_tyvars ->
+ -- Deal with SPECIALISE instance pragmas by making them
+ -- look like SPECIALISE pragmas for the dfun
+ let
+ mk_prag (SpecInstSig ty loc) = SpecSig (idName dfun_id) ty loc
+ mk_prag prag = prag
+
+ all_prags = map mk_prag uprags
+ in
+
+ tcExtendGlobalValEnv [dfun_id] (
+ tcExtendTyVarEnv2 xtve $
+ tcExtendLocalValEnv2 [(idName sel_id, tcSigPolyId sig)
+ | (sel_id, sig, _) <- meth_infos] $
+ -- Map sel_id to the local method name we are using
+ tcSpecSigs all_prags
+ ) `thenTc` \ (prag_binds, prag_lie) ->
-- Create the result bindings
let
where
msg = _PK_ ("Compiler error: bad dictionary " ++ showSDoc (ppr clas))
- dict_bind = VarMonoBind this_dict_id dict_rhs
- method_binds = andMonoBindList method_binds_s
-
- main_bind
- = AbsBinds
- zonked_inst_tyvars
- (map instToId dfun_arg_dicts)
- [(inst_tyvars', local_dfun_id, this_dict_id)]
- inlines
- (lie_binds1 `AndMonoBinds`
- lie_binds2 `AndMonoBinds`
- method_binds `AndMonoBinds`
- dict_bind)
+ dict_bind = VarMonoBind this_dict_id dict_rhs
+ meth_binds = andMonoBindList meth_binds_s
+ all_binds = sc_binds `AndMonoBinds` meth_binds `AndMonoBinds` dict_bind
+
+ main_bind = AbsBinds
+ zonked_inst_tyvars
+ (map instToId dfun_arg_dicts)
+ [(inst_tyvars', local_dfun_id, this_dict_id)]
+ inlines all_binds
in
- returnTc (const_lie1 `plusLIE` const_lie2 `plusLIE` prag_lie,
+ returnTc (plusLIEs meth_lie_s `plusLIE` sc_lie `plusLIE` prag_lie,
main_bind `AndMonoBinds` prag_binds)
\end{code}
projects / ghc-hetmet.git / blobdiff