From: simonpj Date: Thu, 31 Jan 2002 17:48:27 +0000 (+0000) Subject: [project @ 2002-01-31 17:48:26 by simonpj] X-Git-Tag: Approximately_9120_patches~197 X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=b27560c4649d7025456fb9936d5a5cdd1e5dc383;p=ghc-hetmet.git [project @ 2002-01-31 17:48:26 by simonpj] Wibbles to yesterdays changes --- diff --git a/ghc/compiler/typecheck/TcInstDcls.lhs b/ghc/compiler/typecheck/TcInstDcls.lhs index c4023c4..21ed1d5 100644 --- a/ghc/compiler/typecheck/TcInstDcls.lhs +++ b/ghc/compiler/typecheck/TcInstDcls.lhs @@ -5,7 +5,7 @@ \begin{code} module TcInstDcls ( tcInstDecls1, tcIfaceInstDecls1, addInstDFuns, - tcInstDecls2, tcAddDeclCtxt ) where + tcInstDecls2, initInstEnv, tcAddDeclCtxt ) where #include "HsVersions.h" @@ -44,7 +44,8 @@ import PprType ( pprClassPred ) import TcMonoType ( tcHsTyVars, kcHsSigType, tcHsType, tcHsSigType ) import TcUnify ( checkSigTyVars ) import TcSimplify ( tcSimplifyCheck ) -import HscTypes ( HomeSymbolTable, DFunId, PersistentCompilerState(..), +import HscTypes ( HomeSymbolTable, DFunId, + PersistentCompilerState(..), PersistentRenamerState, ModDetails(..), PackageInstEnv ) import Subst ( substTy, substTheta ) @@ -160,9 +161,8 @@ Gather up the instance declarations from their various sources \begin{code} tcInstDecls1 -- Deal with source-code instance decls - :: PersistentCompilerState - -> HomeSymbolTable -- Contains instances - -> TcEnv -- Contains IdInfo for dfun ids + :: PersistentRenamerState + -> InstEnv -- Imported instance envt -> (Name -> Maybe Fixity) -- for deriving Show and Read -> Module -- Module for deriving -> [RenamedTyClDecl] -- For deriving stuff @@ -172,63 +172,52 @@ tcInstDecls1 -- Deal with source-code instance decls -- for this module RenamedHsBinds) -- derived instances -tcInstDecls1 pcs hst unf_env get_fixity - this_mod tycl_decls inst_decls - = let - pkg_inst_env = pcs_insts pcs - prs = pcs_PRS pcs - clas_decls = filter isClassDecl tycl_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 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) 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 - hst_dfuns = foldModuleEnv ((++) . md_insts) [] hst - in - --- pprTrace "tcInstDecls" (vcat [ppr imported_dfuns, ppr hst_dfuns]) $ - - addInstDFuns pkg_inst_env 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 + tcDeriving prs this_mod inst_env2 get_fixity tycl_decls `thenTc` \ (deriv_inst_info, deriv_binds) -> - addInstInfos inst_env4 deriv_inst_info `thenNF_Tc` \ final_inst_env -> + 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) diff --git a/ghc/compiler/typecheck/TcModule.lhs b/ghc/compiler/typecheck/TcModule.lhs index 5bb4062..50ff6f7 100644 --- a/ghc/compiler/typecheck/TcModule.lhs +++ b/ghc/compiler/typecheck/TcModule.lhs @@ -52,7 +52,7 @@ import TcEnv ( TcEnv, RecTcEnv, InstInfo(iDFunId), tcExtendGlobalValEnv, tcLook import TcRules ( tcIfaceRules, tcSourceRules ) import TcForeign ( tcForeignImports, tcForeignExports ) import TcIfaceSig ( tcInterfaceSigs ) -import TcInstDcls ( tcInstDecls1, tcIfaceInstDecls1, addInstDFuns, tcInstDecls2 ) +import TcInstDcls ( tcInstDecls1, tcIfaceInstDecls1, addInstDFuns, initInstEnv, tcInstDecls2 ) import TcUnify ( unifyTauTy ) import TcSimplify ( tcSimplifyTop, tcSimplifyInfer ) import TcTyClsDecls ( tcTyAndClassDecls ) @@ -111,7 +111,7 @@ typecheckStmt dflags pcs hst ic_type_env unqual this_mod names (stmt, iface_decl tcSetDefaultTys defaultDefaultTys $ -- Typecheck the extra declarations - tcExtraDecls pcs this_mod iface_decls `thenTc` \ (new_pcs, env) -> + tcExtraDecls pcs hst this_mod iface_decls `thenTc` \ (new_pcs, env) -> tcSetEnv env $ tcExtendGlobalTypeEnv ic_type_env $ @@ -245,7 +245,7 @@ typecheckExpr dflags pcs hst ic_type_env unqual this_mod (expr, decls) tcSetDefaultTys defaultDefaultTys $ -- Typecheck the extra declarations - tcExtraDecls pcs this_mod decls `thenTc` \ (new_pcs, env) -> + tcExtraDecls pcs hst this_mod decls `thenTc` \ (new_pcs, env) -> -- Now typecheck the expression tcSetEnv env $ @@ -296,15 +296,17 @@ typecheckExtraDecls typecheckExtraDecls dflags pcs hst unqual this_mod decls = typecheck dflags pcs hst unqual $ - tcExtraDecls pcs this_mod decls `thenTc` \ (new_pcs, _) -> + tcExtraDecls pcs hst this_mod decls `thenTc` \ (new_pcs, _) -> returnTc new_pcs tcExtraDecls :: PersistentCompilerState + -> HomeSymbolTable -> Module -> [RenamedHsDecl] -> TcM (PersistentCompilerState, TcEnv) + -- Returned environment includes instances -tcExtraDecls pcs this_mod decls +tcExtraDecls pcs hst this_mod decls = tcIfaceImports this_mod decls `thenTc` \ (env, all_things, dfuns, rules) -> addInstDFuns (pcs_insts pcs) dfuns `thenNF_Tc` \ new_pcs_insts -> let @@ -317,8 +319,11 @@ tcExtraDecls pcs this_mod decls pcs_rules = new_pcs_rules } in - -- Add the new instances - tcSetEnv env (tcSetInstEnv new_pcs_insts tcGetEnv) `thenNF_Tc` \ new_env -> + -- Initialise the instance environment + tcSetEnv env ( + initInstEnv new_pcs hst `thenNF_Tc` \ inst_env -> + tcSetInstEnv inst_env tcGetEnv + ) `thenNF_Tc` \ new_env -> returnTc (new_pcs, new_env) \end{code} @@ -386,10 +391,11 @@ tcModule pcs hst get_fixity this_mod decls tcSetEnv env1 $ -- Do the source-language instances, including derivings - tcInstDecls1 new_pcs hst unf_env + initInstEnv new_pcs hst `thenNF_Tc` \ inst_env1 -> + tcInstDecls1 (pcs_PRS new_pcs) inst_env1 get_fixity this_mod - tycl_decls src_inst_decls `thenTc` \ (inst_env, inst_info, deriv_binds) -> - tcSetInstEnv inst_env $ + tycl_decls src_inst_decls `thenTc` \ (inst_env2, inst_info, deriv_binds) -> + tcSetInstEnv inst_env2 $ -- Foreign import declarations next traceTc (text "Tc4") `thenNF_Tc_` diff --git a/ghc/compiler/typecheck/TcSimplify.lhs b/ghc/compiler/typecheck/TcSimplify.lhs index 88827cd..775cf75 100644 --- a/ghc/compiler/typecheck/TcSimplify.lhs +++ b/ghc/compiler/typecheck/TcSimplify.lhs @@ -1738,7 +1738,6 @@ tcSimplifyDeriv tyvars theta simpleReduceLoop doc reduceMe wanteds `thenTc` \ (frees, _, irreds) -> ASSERT( null frees ) -- reduceMe never returns Free - doptsTc Opt_AllowUndecidableInstances `thenNF_Tc` \ undecidable_ok -> let tv_set = mkVarSet tvs simpl_theta = map dictPred irreds -- reduceMe squashes all non-dicts @@ -1746,8 +1745,11 @@ tcSimplifyDeriv tyvars theta check_pred pred -- Check that the returned dictionaries are all of form (C a b) -- (where a, b are type variables). - -- Unless we have -fallow-undecidable-instances. - | not undecidable_ok && not (isTyVarClassPred pred) + -- At one time we allowed this if we had -fallow-undecidable-instances, + -- but that risks non-termination in the 'deriving' context-inference + -- fixpoint loop. If you want fancy stuff you just have to write the + -- instance decl yourself. + | not (isTyVarClassPred pred) = addErrTc (noInstErr pred) -- Check for a bizarre corner case, when the derived instance decl should