\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 HsSyn ( HsDecl(..), InstDecl(..), TyClDecl(..), HsType(..),
MonoBinds(..), HsExpr(..), HsLit(..), Sig(..), HsTyVarBndr(..),
andMonoBindList, collectMonoBinders,
- isClassDecl, isIfaceInstDecl, toHsType
+ isClassDecl, toHsType
)
import RnHsSyn ( RenamedHsBinds, RenamedInstDecl, RenamedHsDecl,
RenamedMonoBinds, RenamedTyClDecl, RenamedHsType,
import TcMonoType ( tcHsTyVars, kcHsSigType, tcHsType, tcHsSigType )
import TcUnify ( checkSigTyVars )
import TcSimplify ( tcSimplifyCheck )
-import HscTypes ( HomeSymbolTable, DFunId,
- ModDetails(..), PackageInstEnv, PersistentRenamerState
+import HscTypes ( HomeSymbolTable, DFunId,
+ PersistentCompilerState(..), PersistentRenamerState,
+ ModDetails(..), PackageInstEnv
)
import Subst ( substTy, substTheta )
import DataCon ( classDataCon )
Gather up the instance declarations from their various sources
\begin{code}
-tcInstDecls1
- :: PackageInstEnv
- -> PersistentRenamerState
- -> HomeSymbolTable -- Contains instances
- -> TcEnv -- Contains IdInfo for dfun ids
+tcInstDecls1 -- Deal with source-code instance decls
+ :: PersistentRenamerState
+ -> InstEnv -- Imported instance envt
-> (Name -> Maybe Fixity) -- for deriving Show and Read
-> Module -- Module for deriving
- -> [RenamedHsDecl]
- -> TcM (PackageInstEnv, -- cached package inst env
- InstEnv, -- the full inst env
- [InstInfo], -- instance decls to process
- [DFunId], -- instances from this module, for its iface
+ -> [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 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
- (iface_inst_ds, local_inst_ds) = partition isIfaceInstDecl inst_decls
- in
+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 iface_inst_ds `thenNF_Tc` \ iface_dfuns ->
-
- -- (2) Instances from generic class declarations
- getGenericInstances clas_decls `thenTc` \ generic_inst_info ->
+ mapNF_Tc tcLocalInstDecl1 inst_decls `thenNF_Tc` \ local_inst_infos ->
- -- Next, construct the instance environment so far, consisting of
- -- a) cached non-home-package InstEnv (gotten from pcs) inst_env0
- -- b) imported instance decls (not in the home package) inst_env1
- -- c) other modules in this package (gotten from hst) inst_env2
- -- d) imported instance decls (from this module) inst_env3
- -- e) local instance decls inst_env4
- -- f) generic instances inst_env5
- -- The result of (b) replaces the cached InstEnv in the PCS
- --
- -- Note that iface_dfuns may contain not only insts that we
- -- demand-loaded from interface files, but also instances from
- -- the current module in the case where we are loading this
- -- module's interface file in GHCi, so we partition the
- -- iface_dfuns into non-local and local instances so that we
- -- don't end up with home package instances in the PCS.
- --
- -- There can't be any instance declarations from the home
- -- package other than from the current module (with the
- -- compilation manager) because they are loaded explicitly by
- -- the compilation manager.
let
local_inst_info = catMaybes local_inst_infos
- (local_iface_dfuns, pkg_iface_dfuns)
- = partition (isLocalThing this_mod) iface_dfuns
- hst_dfuns = foldModuleEnv ((++) . md_insts) [] hst
- in
-
--- pprTrace "tcInstDecls" (vcat [ppr imported_dfuns, ppr hst_dfuns]) $
+ clas_decls = filter isClassDecl tycl_decls
+ in
+ -- (2) Instances from generic class declarations
+ getGenericInstances clas_decls `thenTc` \ generic_inst_info ->
- addInstDFuns inst_env0 pkg_iface_dfuns `thenNF_Tc` \ inst_env1 ->
- addInstDFuns inst_env1 hst_dfuns `thenNF_Tc` \ inst_env2 ->
- addInstDFuns inst_env2 local_iface_dfuns `thenNF_Tc` \ inst_env3 ->
- addInstInfos inst_env3 local_inst_info `thenNF_Tc` \ inst_env4 ->
- addInstInfos inst_env4 generic_inst_info `thenNF_Tc` \ inst_env5 ->
+ -- Next, construct the instance environment so far, consisting of
+ -- 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_env5
- tcDeriving prs this_mod inst_env5 get_fixity tycl_decls
- `thenTc` \ (deriv_inst_info, deriv_binds) ->
- addInstInfos inst_env5 deriv_inst_info `thenNF_Tc` \ final_inst_env ->
- let inst_info = generic_inst_info ++ deriv_inst_info ++ local_inst_info in
-
- returnTc (inst_env1,
- final_inst_env,
- inst_info,
- local_iface_dfuns ++ map iDFunId inst_info,
+ -- needs to know about all the instances possible; hence inst_env4
+ 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 (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
projects / ghc-hetmet.git / blobdiff