X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcRnTypes.lhs;h=33190e798768fc0c01be73acdc82ae3135a8ef79;hb=ff818166a0a06e77becad9e28ed116f3b7f5cc8b;hp=1e58eddafc4d8c997900ef85f21b85146331a0b4;hpb=3355c9d53b220ccb110e5a3c81a1a8b2c9c41555;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcRnTypes.lhs b/ghc/compiler/typecheck/TcRnTypes.lhs index 1e58edd..33190e7 100644 --- a/ghc/compiler/typecheck/TcRnTypes.lhs +++ b/ghc/compiler/typecheck/TcRnTypes.lhs @@ -3,90 +3,77 @@ % \begin{code} module TcRnTypes( - TcRn, TcM, RnM, -- The monad is opaque outside this module + TcRnIf, TcRn, TcM, RnM, IfM, IfL, IfG, -- The monad is opaque outside this module + TcRef, - -- Standard monadic operations - thenM, thenM_, returnM, failM, - - -- Non-standard operations - runTcRn, fixM, tryM, ioToTcRn, - newMutVar, readMutVar, writeMutVar, - getEnv, setEnv, updEnv, unsafeInterleaveM, - -- The environment types - Env(..), TopEnv(..), TcGblEnv(..), - TcLclEnv(..), RnLclEnv(..), + Env(..), + TcGblEnv(..), TcLclEnv(..), + IfGblEnv(..), IfLclEnv(..), -- Ranamer types - RnMode(..), isInterfaceMode, isCmdLineMode, - EntityUsage, emptyUsages, ErrCtxt, + ErrCtxt, ImportAvails(..), emptyImportAvails, plusImportAvails, plusAvail, pruneAvails, AvailEnv, emptyAvailEnv, unitAvailEnv, plusAvailEnv, - mkAvailEnv, lookupAvailEnv, availEnvElts, addAvail, - WhereFrom(..), + mkAvailEnv, lookupAvailEnv, lookupAvailEnv_maybe, availEnvElts, addAvail, + WhereFrom(..), mkModDeps, -- Typechecker types - TcTyThing(..), + TcTyThing(..), pprTcTyThingCategory, GadtRefinement, -- Template Haskell - Stage(..), topStage, topSpliceStage, - Level, impLevel, topLevel, + ThStage(..), topStage, topSpliceStage, + ThLevel, impLevel, topLevel, + + -- Arrows + ArrowCtxt(..), topArrowCtxt, ProcLevel, topProcLevel, -- Insts - Inst(..), InstOrigin(..), InstLoc(..), pprInstLoc, instLocSrcLoc, + Inst(..), InstOrigin(..), InstLoc(..), pprInstLoc, + instLocSrcLoc, instLocSrcSpan, LIE, emptyLIE, unitLIE, plusLIE, consLIE, plusLIEs, mkLIE, isEmptyLIE, lieToList, listToLIE, -- Misc other types - TcRef, TcId, TcIdSet + TcId, TcIdSet, TcDictBinds ) where #include "HsVersions.h" -import HsSyn ( PendingSplice, HsOverLit, MonoBinds, RuleDecl, ForeignDecl ) -import RnHsSyn ( RenamedHsExpr, RenamedPat, RenamedArithSeqInfo ) -import HscTypes ( GhciMode, ExternalPackageState, HomePackageTable, NameCache, - GlobalRdrEnv, LocalRdrEnv, FixityEnv, TypeEnv, TyThing, - Avails, GenAvailInfo(..), AvailInfo, availName, - IsBootInterface, Deprecations ) -import Packages ( PackageName ) -import TcType ( TcTyVarSet, TcType, TcTauType, TcThetaType, TcPredType, TcKind, - tcCmpPred, tcCmpType, tcCmpTypes ) +import HsSyn ( PendingSplice, HsOverLit, LRuleDecl, LForeignDecl, + ArithSeqInfo, DictBinds, LHsBinds ) +import HscTypes ( FixityEnv, + HscEnv, TypeEnv, TyThing, + GenAvailInfo(..), AvailInfo, HscSource(..), + availName, IsBootInterface, Deprecations ) +import Packages ( PackageId ) +import Type ( Type, TvSubstEnv, pprParendType, pprTyThingCategory ) +import TcType ( TcTyVarSet, TcType, TcTauType, TcThetaType, SkolemInfo, + TcPredType, TcKind, tcCmpPred, tcCmpType, tcCmpTypes, pprSkolInfo ) import InstEnv ( DFunId, InstEnv ) +import IOEnv +import RdrName ( GlobalRdrEnv, LocalRdrEnv ) import Name ( Name ) import NameEnv -import NameSet ( NameSet, emptyNameSet ) -import Type ( Type ) -import Class ( Class ) +import NameSet ( NameSet, unionNameSets, DefUses ) +import OccName ( OccEnv ) import Var ( Id, TyVar ) import VarEnv ( TidyEnv ) import Module -import SrcLoc ( SrcLoc ) +import SrcLoc ( SrcSpan, SrcLoc, srcSpanStart ) import VarSet ( IdSet ) import ErrUtils ( Messages, Message ) -import CmdLineOpts ( DynFlags ) import UniqSupply ( UniqSupply ) import BasicTypes ( IPName ) import Util ( thenCmp ) import Bag import Outputable -import DATA_IOREF ( IORef, newIORef, readIORef, writeIORef ) -import UNSAFE_IO ( unsafeInterleaveIO ) -import FIX_IO ( fixIO ) -import EXCEPTION ( Exception ) import Maybe ( mapMaybe ) import ListSetOps ( unionLists ) -import Panic ( tryMost ) \end{code} -\begin{code} -type TcRef a = IORef a -type TcId = Id -- Type may be a TcType -type TcIdSet = IdSet -\end{code} - %************************************************************************ %* * Standard monad definition for TcRn @@ -94,111 +81,23 @@ type TcIdSet = IdSet %* * %************************************************************************ -The monad itself has to be defined here, -because it is mentioned by ErrCtxt +The monad itself has to be defined here, because it is mentioned by ErrCtxt \begin{code} -newtype TcRn m a = TcRn (Env m -> IO a) -unTcRn (TcRn f) = f +type TcRef a = IORef a +type TcId = Id -- Type may be a TcType +type TcIdSet = IdSet +type TcDictBinds = DictBinds TcId -- Bag of dictionary bindings -type TcM a = TcRn TcLclEnv a -type RnM a = TcRn RnLclEnv a -returnM :: a -> TcRn m a -returnM a = TcRn (\ env -> return a) -thenM :: TcRn m a -> (a -> TcRn m b) -> TcRn m b -thenM (TcRn m) f = TcRn (\ env -> do { r <- m env ; - unTcRn (f r) env }) - -thenM_ :: TcRn m a -> TcRn m b -> TcRn m b -thenM_ (TcRn m) f = TcRn (\ env -> do { m env ; unTcRn f env }) - -failM :: TcRn m a -failM = TcRn (\ env -> ioError (userError "TcRn failure")) - -instance Monad (TcRn m) where - (>>=) = thenM - (>>) = thenM_ - return = returnM - fail s = failM -- Ignore the string -\end{code} - - -%************************************************************************ -%* * - Fundmantal combinators specific to the monad -%* * -%************************************************************************ - -Running it - -\begin{code} -runTcRn :: Env m -> TcRn m a -> IO a -runTcRn env (TcRn m) = m env -\end{code} - -The fixpoint combinator - -\begin{code} -{-# NOINLINE fixM #-} - -- Aargh! Not inlining fixTc alleviates a space leak problem. - -- Normally fixTc is used with a lazy tuple match: if the optimiser is - -- shown the definition of fixTc, it occasionally transforms the code - -- in such a way that the code generator doesn't spot the selector - -- thunks. Sigh. - -fixM :: (a -> TcRn m a) -> TcRn m a -fixM f = TcRn (\ env -> fixIO (\ r -> unTcRn (f r) env)) -\end{code} - -Error recovery - -\begin{code} -tryM :: TcRn m r -> TcRn m (Either Exception r) --- Reflect exception into TcRn monad -tryM (TcRn thing) = TcRn (\ env -> tryMost (thing env)) -\end{code} - -Lazy interleave - -\begin{code} -unsafeInterleaveM :: TcRn m a -> TcRn m a -unsafeInterleaveM (TcRn m) = TcRn (\ env -> unsafeInterleaveIO (m env)) -\end{code} - -\end{code} - -Performing arbitrary I/O, plus the read/write var (for efficiency) - -\begin{code} -ioToTcRn :: IO a -> TcRn m a -ioToTcRn io = TcRn (\ env -> io) - -newMutVar :: a -> TcRn m (TcRef a) -newMutVar val = TcRn (\ env -> newIORef val) - -writeMutVar :: TcRef a -> a -> TcRn m () -writeMutVar var val = TcRn (\ env -> writeIORef var val) - -readMutVar :: TcRef a -> TcRn m a -readMutVar var = TcRn (\ env -> readIORef var) -\end{code} - -Getting the environment - -\begin{code} -getEnv :: TcRn m (Env m) -{-# INLINE getEnv #-} -getEnv = TcRn (\ env -> return env) - -setEnv :: Env n -> TcRn n a -> TcRn m a -{-# INLINE setEnv #-} -setEnv new_env (TcRn m) = TcRn (\ env -> m new_env) - -updEnv :: (Env m -> Env n) -> TcRn n a -> TcRn m a -{-# INLINE updEnv #-} -updEnv upd (TcRn m) = TcRn (\ env -> m (upd env)) +type TcRnIf a b c = IOEnv (Env a b) c +type IfM lcl a = TcRnIf IfGblEnv lcl a -- Iface stuff +type IfG a = IfM () a -- Top level +type IfL a = IfM IfLclEnv a -- Nested +type TcRn a = TcRnIf TcGblEnv TcLclEnv a +type RnM a = TcRn a -- Historical +type TcM a = TcRn a -- Historical \end{code} @@ -209,50 +108,19 @@ updEnv upd (TcRn m) = TcRn (\ env -> m (upd env)) %************************************************************************ \begin{code} -data Env a -- Changes as we move into an expression +data Env gbl lcl -- Changes as we move into an expression = Env { - env_top :: TopEnv, -- Top-level stuff that never changes - -- Mainly a bunch of updatable refs - -- Includes all info about imported things - env_gbl :: TcGblEnv, -- Info about things defined at the top leve - -- of the module being compiled + env_top :: HscEnv, -- Top-level stuff that never changes + -- Includes all info about imported things - env_lcl :: a, -- Different for the type checker - -- and the renamer + env_us :: TcRef UniqSupply, -- Unique supply for local varibles - env_loc :: SrcLoc -- Source location - } + env_gbl :: gbl, -- Info about things defined at the top level + -- of the module being compiled -data TopEnv -- Built once at top level then does not change - -- Concerns imported stuff - -- Exceptions: error recovery points, meta computation points - = TopEnv { - top_mode :: GhciMode, - top_dflags :: DynFlags, - - -- Stuff about imports - top_eps :: TcRef ExternalPackageState, - -- PIT, ImportedModuleInfo - -- DeclsMap, IfaceRules, IfaceInsts, InstGates - -- TypeEnv, InstEnv, RuleBase - -- Mutable, because we demand-load declarations that extend the state - - top_hpt :: HomePackageTable, - -- The home package table that we've accumulated while - -- compiling the home package, - -- *excluding* the module we are compiling right now. - -- (In one-shot mode the current module is the only - -- home-package module, so tc_hpt is empty. All other - -- modules count as "external-package" modules.) - -- tc_hpt is not mutable because we only demand-load - -- external packages; the home package is eagerly - -- loaded by the compilation manager. - - -- The global name supply - top_nc :: TcRef NameCache, -- Maps original names to Names - top_us :: TcRef UniqSupply, -- Unique supply for this module - top_errs :: TcRef Messages - } + env_lcl :: lcl -- Nested stuff; changes as we go into + -- an expression + } -- TcGblEnv describes the top-level of the module at the -- point at which the typechecker is finished work. @@ -260,12 +128,15 @@ data TopEnv -- Built once at top level then does not change data TcGblEnv = TcGblEnv { - tcg_mod :: Module, -- Module being compiled - tcg_usages :: TcRef EntityUsage, -- What version of what entities - -- have been used from other home-pkg modules + tcg_mod :: Module, -- Module being compiled + tcg_src :: HscSource, -- What kind of module + -- (regular Haskell, hs-boot, ext-core) + tcg_rdr_env :: GlobalRdrEnv, -- Top level envt; used during renaming - tcg_fix_env :: FixityEnv, -- Ditto - tcg_default :: [Type], -- Types used for defaulting + tcg_default :: Maybe [Type], -- Types used for defaulting + -- Nothing => no 'default' decl + + tcg_fix_env :: FixityEnv, -- Just for things in this module tcg_type_env :: TypeEnv, -- Global type env for the module we are compiling now -- All TyCons and Classes (for this module) end up in here right away, @@ -273,39 +144,106 @@ data TcGblEnv -- -- (Ids defined in this module start in the local envt, -- though they move to the global envt during zonking) - - tcg_inst_env :: TcRef InstEnv, -- Global instance env: a combination of - -- tc_pcs, tc_hpt, *and* tc_insts - -- This field is mutable so that it can be updated inside a - -- Template Haskell splice, which might suck in some new - -- instance declarations. This is a slightly different strategy - -- than for the type envt, where we look up first in tcg_type_env - -- and then in the mutable EPS, because the InstEnv for this module - -- is constructed (in principle at least) only from the modules - -- 'below' this one, so it's this-module-specific - -- - -- On the other hand, a declaration quote [d| ... |] may introduce - -- some new instance declarations that we *don't* want to persist - -- outside the quote, so we tiresomely need to revert the InstEnv - -- after finishing the quote (see TcSplice.tcBracket) + tcg_type_env_var :: TcRef TypeEnv, + -- Used only to initialise the interface-file + -- typechecker in initIfaceTcRn, so that it can see stuff + -- bound in this module when dealing with hi-boot recursions + -- Updated at intervals (e.g. after dealing with types and classes) + + tcg_inst_env :: InstEnv, -- Instance envt for *home-package* modules + -- Includes the dfuns in tcg_insts -- Now a bunch of things about this module that are simply -- accumulated, but never consulted until the end. -- Nevertheless, it's convenient to accumulate them along -- with the rest of the info from this module. - tcg_exports :: Avails, -- What is exported - tcg_imports :: ImportAvails, -- Information about what was imported - -- from where, including things bound - -- in this module + tcg_exports :: NameSet, -- What is exported + tcg_imports :: ImportAvails, -- Information about what was imported + -- from where, including things bound + -- in this module + + tcg_dus :: DefUses, -- What is defined in this module and what is used. + -- The latter is used to generate + -- (a) version tracking; no need to recompile if these + -- things have not changed version stamp + -- (b) unused-import info + + tcg_keep :: TcRef NameSet, -- Locally-defined top-level names to keep alive + -- "Keep alive" means give them an Exported flag, so + -- that the simplifier does not discard them as dead + -- code, and so that they are exposed in the interface file + -- (but not to export to the user). + -- + -- Some things, like dict-fun Ids and default-method Ids are + -- "born" with the Exported flag on, for exactly the above reason, + -- but some we only discover as we go. Specifically: + -- * The to/from functions for generic data types + -- * Top-level variables appearing free in the RHS of an orphan rule + -- * Top-level variables appearing free in a TH bracket + + tcg_inst_uses :: TcRef NameSet, -- Home-package Dfuns actually used + -- Used to generate version dependencies + -- This records usages, rather like tcg_dus, but it has to + -- be a mutable variable so it can be augmented + -- when we look up an instance. These uses of dfuns are + -- rather like the free variables of the program, but + -- are implicit instead of explicit. + + tcg_th_used :: TcRef Bool, -- True <=> Template Haskell syntax used + -- We need this so that we can generate a dependency on the + -- Template Haskell package, becuase the desugarer is going to + -- emit loads of references to TH symbols. It's rather like + -- tcg_inst_uses; the reference is implicit rather than explicit, + -- so we have to zap a mutable variable. -- The next fields accumulate the payload of the module -- The binds, rules and foreign-decl fiels are collected -- initially in un-zonked form and are finally zonked in tcRnSrcDecls - tcg_binds :: MonoBinds Id, -- Value bindings in this module + tcg_binds :: LHsBinds Id, -- Value bindings in this module tcg_deprecs :: Deprecations, -- ...Deprecations tcg_insts :: [DFunId], -- ...Instances - tcg_rules :: [RuleDecl Id], -- ...Rules - tcg_fords :: [ForeignDecl Id] -- ...Foreign import & exports + tcg_rules :: [LRuleDecl Id], -- ...Rules + tcg_fords :: [LForeignDecl Id] -- ...Foreign import & exports + } +\end{code} + +%************************************************************************ +%* * + The interface environments + Used when dealing with IfaceDecls +%* * +%************************************************************************ + +\begin{code} +data IfGblEnv + = IfGblEnv { + -- The type environment for the module being compiled, + -- in case the interface refers back to it via a reference that + -- was originally a hi-boot file. + -- We need the module name so we can test when it's appropriate + -- to look in this env. + if_rec_types :: Maybe (Module, IfG TypeEnv) + -- Allows a read effect, so it can be in a mutable + -- variable; c.f. handling the external package type env + -- Nothing => interactive stuff, no loops possible + } + +data IfLclEnv + = IfLclEnv { + -- The module for the current IfaceDecl + -- So if we see f = \x -> x + -- it means M.f = \x -> x, where M is the if_mod + if_mod :: Module, + + -- The field is used only for error reporting + -- if (say) there's a Lint error in it + if_loc :: SDoc, + -- Where the interface came from: + -- .hi file, or GHCi state, or ext core + -- plus which bit is currently being examined + + if_tv_env :: OccEnv TyVar, -- Nested tyvar bindings + if_id_env :: OccEnv Id -- Nested id binding } \end{code} @@ -332,38 +270,72 @@ Why? Because they are now Ids not TcIds. This final GlobalEnv is b) used in the ModDetails of this module \begin{code} -data TcLclEnv +data TcLclEnv -- Changes as we move inside an expression + -- Discarded after typecheck/rename; not passed on to desugarer = TcLclEnv { - tcl_ctxt :: ErrCtxt, -- Error context - - tcl_level :: Stage, -- Template Haskell context + tcl_loc :: SrcSpan, -- Source span + tcl_ctxt :: ErrCtxt, -- Error context + tcl_errs :: TcRef Messages, -- Place to accumulate errors + + tcl_th_ctxt :: ThStage, -- Template Haskell context + tcl_arrow_ctxt :: ArrowCtxt, -- Arrow-notation context + + tcl_rdr :: LocalRdrEnv, -- Local name envt + -- Maintained during renaming, of course, but also during + -- type checking, solely so that when renaming a Template-Haskell + -- splice we have the right environment for the renamer. + -- + -- Does *not* include global name envt; may shadow it + -- Includes both ordinary variables and type variables; + -- they are kept distinct because tyvar have a different + -- occurrence contructor (Name.TvOcc) + -- We still need the unsullied global name env so that + -- we can look up record field names - tcl_env :: NameEnv TcTyThing, -- The local type environment: Ids and TyVars - -- defined in this module + tcl_env :: NameEnv TcTyThing, -- The local type environment: Ids and TyVars + -- defined in this module tcl_tyvars :: TcRef TcTyVarSet, -- The "global tyvars" - -- Namely, the in-scope TyVars bound in tcl_lenv, - -- plus the tyvars mentioned in the types of - -- Ids bound in tcl_lenv - -- Why mutable? see notes with tcGetGlobalTyVars + -- Namely, the in-scope TyVars bound in tcl_env, + -- plus the tyvars mentioned in the types of Ids bound in tcl_lenv + -- Why mutable? see notes with tcGetGlobalTyVars - tcl_lie :: TcRef LIE -- Place to accumulate type constraints + tcl_lie :: TcRef LIE, -- Place to accumulate type constraints + tcl_gadt :: GadtRefinement -- The current type refinement for GADTs + +----------------------------------------------------------- +-- Not yet; it's a new complication and I want to see whether it bites +-- tcl_given :: [Inst] -- Insts available in the current context (see Note [Given Insts]) +----------------------------------------------------------- } -type Level = Int +type GadtRefinement = TvSubstEnv -- Binds rigid type variables to their refinements -data Stage - = Comp -- Ordinary compiling, at level topLevel - | Splice Level -- Inside a splice - | Brack Level -- Inside brackets; - (TcRef [PendingSplice]) -- accumulate pending splices here - (TcRef LIE) -- and type constraints here -topStage, topSpliceStage :: Stage -topStage = Comp -topSpliceStage = Splice (topLevel - 1) -- Stage for the body of a top-level splice +{- Note [Given Insts] + ~~~~~~~~~~~~~~~~~~ +Because of GADTs, we have to pass inwards the Insts provided by type signatures +and existential contexts. Consider + data T a where { T1 :: b -> b -> T [b] } + f :: Eq a => T a -> Bool + f (T1 x y) = [x]==[y] + +The constructor T1 binds an existential variable 'b', and we need Eq [b]. +Well, we have it, because Eq a refines to Eq [b], but we can only spot that if we +pass it inwards. + +-} + +--------------------------- +-- Template Haskell levels +--------------------------- +type ThLevel = Int + -- Indicates how many levels of brackets we are inside + -- (always >= 0) + -- Incremented when going inside a bracket, + -- decremented when going inside a splice -impLevel, topLevel :: Level +impLevel, topLevel :: ThLevel topLevel = 1 -- Things defined at top level of this module impLevel = 0 -- Imported things; they can be used inside a top level splice -- @@ -372,87 +344,89 @@ impLevel = 0 -- Imported things; they can be used inside a top level splice -- g1 = $(map ...) is OK -- g2 = $(f ...) is not OK; because we havn't compiled f yet -data TcTyThing - = AGlobal TyThing -- Used only in the return type of a lookup - | ATcId TcId Level -- Ids defined in this module; may not be fully zonked - | ATyVar TyVar -- Type variables - | AThing TcKind -- Used temporarily, during kind checking --- Here's an example of how the AThing guy is used --- Suppose we are checking (forall a. T a Int): --- 1. We first bind (a -> AThink kv), where kv is a kind variable. --- 2. Then we kind-check the (T a Int) part. --- 3. Then we zonk the kind variable. --- 4. Now we know the kind for 'a', and we add (a -> ATyVar a::K) to the environment -instance Outputable TcTyThing where -- Debugging only - ppr (AGlobal g) = text "AGlobal" <+> ppr g - ppr (ATcId g l) = text "ATcId" <+> ppr g <+> ppr l - ppr (ATyVar t) = text "ATyVar" <+> ppr t - ppr (AThing k) = text "AThing" <+> ppr k -\end{code} +data ThStage + = Comp -- Ordinary compiling, at level topLevel + | Splice ThLevel -- Inside a splice + | Brack ThLevel -- Inside brackets; + (TcRef [PendingSplice]) -- accumulate pending splices here + (TcRef LIE) -- and type constraints here +topStage, topSpliceStage :: ThStage +topStage = Comp +topSpliceStage = Splice (topLevel - 1) -- Stage for the body of a top-level splice -\begin{code} -type ErrCtxt = [TidyEnv -> TcM (TidyEnv, Message)] - -- Innermost first. Monadic so that we have a chance - -- to deal with bound type variables just before error - -- message construction -\end{code} +--------------------------- +-- Arrow-notation stages +--------------------------- -%************************************************************************ -%* * - The local renamer environment -%* * -%************************************************************************ +-- In arrow notation, a variable bound by a proc (or enclosed let/kappa) +-- is not in scope to the left of an arrow tail (-<). For example +-- +-- proc x -> (e1 -< e2) +-- +-- Here, x is not in scope in e1, but it is in scope in e2. This can get +-- a bit complicated: +-- +-- let x = 3 in +-- prox y -> (proc z -> e1) -< e2 +-- +-- Here, x and z are in scope in e1, but y is not. Here's how we track this: +-- a) Assign an "proc level" to each proc, being the number of +-- lexically-enclosing procs + 1. +-- b) Assign to each local variable the proc-level of its lexically +-- enclosing proc. +-- c) Keep a list of out-of-scope procs. When moving to the left of +-- an arrow-tail, add the proc-level of the immediately enclosing +-- proc to the list. +-- d) When looking up a variable, complain if its proc-level is in +-- the banned list -\begin{code} -data RnLclEnv - = RnLclEnv { - rn_mode :: RnMode, - rn_lenv :: LocalRdrEnv -- Local name envt - -- Does *not* include global name envt; may shadow it - -- Includes both ordinary variables and type variables; - -- they are kept distinct because tyvar have a different - -- occurrence contructor (Name.TvOcc) - -- We still need the unsullied global name env so that - -- we can look up record field names - } +type ProcLevel = Int -- Always >= 0 +topProcLevel = 0 -- Not inside any proc -data RnMode = SourceMode -- Renaming source code - | InterfaceMode Module -- Renaming interface declarations from M - | CmdLineMode -- Renaming a command-line expression +data ArrowCtxt = ArrCtxt { proc_level :: ProcLevel, -- Current level + proc_banned :: [ProcLevel] } -- Out of scope proc-levels -isInterfaceMode (InterfaceMode _) = True -isInterfaceMode _ = False +topArrowCtxt = ArrCtxt { proc_level = topProcLevel, proc_banned = [] } -isCmdLineMode CmdLineMode = True -isCmdLineMode _ = False -\end{code} +--------------------------- +-- TcTyThing +--------------------------- +data TcTyThing + = AGlobal TyThing -- Used only in the return type of a lookup -%************************************************************************ -%* * - EntityUsage -%* * -%************************************************************************ + | ATcId TcId ThLevel ProcLevel -- Ids defined in this module; may not be fully zonked -EntityUsage tells what things are actually need in order to compile this -module. It is used for generating the usage-version field of the ModIface. + | ATyVar Name TcType -- Type variables; tv -> type. It can't just be a TyVar + -- that is mutated to point to the type it is bound to, + -- because that would make it a wobbly type, and we + -- want pattern-bound lexically-scoped type variables to + -- be able to stand for rigid types -Note that we do not record version info for entities from -other (non-home) packages. If the package changes, GHC doesn't help. + | AThing TcKind -- Used temporarily, during kind checking, for the + -- tycons and clases in this recursive group + +instance Outputable TcTyThing where -- Debugging only + ppr (AGlobal g) = ppr g + ppr (ATcId g tl pl) = text "Identifier" <> + ifPprDebug (brackets (ppr g <> comma <> ppr tl <> comma <> ppr pl)) + ppr (ATyVar tv ty) = text "Type variable" <+> quotes (ppr tv) <+> pprParendType ty + ppr (AThing k) = text "AThing" <+> ppr k + +pprTcTyThingCategory :: TcTyThing -> SDoc +pprTcTyThingCategory (AGlobal thing) = pprTyThingCategory thing +pprTcTyThingCategory (ATyVar _ _) = ptext SLIT("Type variable") +pprTcTyThingCategory (ATcId _ _ _) = ptext SLIT("Local identifier") +pprTcTyThingCategory (AThing _) = ptext SLIT("Kinded thing") +\end{code} \begin{code} -type EntityUsage = NameSet - -- The Names are all the (a) home-package - -- (b) "big" (i.e. no data cons, class ops) - -- (c) non-locally-defined - -- (d) non-wired-in - -- names that have been slurped in so far. - -- This is used to generate the "usage" information for this module. - -emptyUsages :: EntityUsage -emptyUsages = emptyNameSet +type ErrCtxt = [TidyEnv -> TcM (TidyEnv, Message)] + -- Innermost first. Monadic so that we have a chance + -- to deal with bound type variables just before error + -- message construction \end{code} @@ -463,41 +437,41 @@ emptyUsages = emptyNameSet %************************************************************************ ImportAvails summarises what was imported from where, irrespective -of whether the imported htings are actually used or not -It is used * when porcessing the export list +of whether the imported things are actually used or not +It is used * when processing the export list * when constructing usage info for the inteface file * to identify the list of directly imported modules for initialisation purposes + * when figuring out what things are really unused \begin{code} data ImportAvails = ImportAvails { - imp_env :: AvailEnv, - -- All the things that are available from the import - -- Its domain is all the "main" things; - -- i.e. *excluding* class ops and constructors - -- (which appear inside their parent AvailTC) - - imp_qual :: ModuleEnv AvailEnv, - -- Used to figure out "module M" export specifiers + imp_env :: ModuleEnv NameSet, + -- All the things imported, classified by + -- the *module qualifier* for its import + -- e.g. import List as Foo + -- would add a binding Foo |-> ...stuff from List... + -- to imp_env. + -- + -- We need to classify them like this so that we can figure out + -- "module M" export specifiers in an export list -- (see 1.4 Report Section 5.1.1). Ultimately, we want to find -- everything that is unambiguously in scope as 'M.x' -- and where plain 'x' is (perhaps ambiguously) in scope. -- So the starting point is all things that are in scope as 'M.x', -- which is what this field tells us. - -- - -- Domain is the *module qualifier* for imports. - -- e.g. import List as Foo - -- would add a binding Foo |-> ...stuff from List... - -- to imp_qual. - -- We keep the stuff as an AvailEnv so that it's easy to - -- combine stuff coming from different (unqualified) - -- imports of the same module - imp_mods :: ModuleEnv (Module, Bool), + imp_mods :: ModuleEnv (Module, Maybe Bool, SrcSpan), -- Domain is all directly-imported modules - -- Bool is True if there was an unrestricted import - -- (i.e. not a selective list) + -- Maybe value answers the question "is the import restricted?" + -- Nothing => unrestricted import (e.g., "import Foo") + -- Just True => restricted import, at least one entity (e.g., "import Foo(x)") + -- Just False => fully restricted import (e.g., "import Foo ()") + -- + -- A distinction is made between the first and the third in order + -- to more precisely emit warnings about unused imports. + -- -- We need the Module in the range because we can't get -- the keys of a ModuleEnv -- Used @@ -506,27 +480,33 @@ data ImportAvails -- need to recompile if the module version changes -- (b) to specify what child modules to initialise - imp_dep_mods :: ModuleEnv (ModuleName, IsBootInterface), + imp_dep_mods :: ModuleEnv (Module, IsBootInterface), -- Home-package modules needed by the module being compiled -- - -- It doesn't matter whether any of these dependencies are actually - -- *used* when compiling the module; they are listed if they are below - -- it at all. For example, suppose M imports A which imports X. Then - -- compiling M might not need to consult X.hi, but X is still listed - -- in M's dependencies. - - imp_dep_pkgs :: [PackageName], + -- It doesn't matter whether any of these dependencies + -- are actually *used* when compiling the module; they + -- are listed if they are below it at all. For + -- example, suppose M imports A which imports X. Then + -- compiling M might not need to consult X.hi, but X + -- is still listed in M's dependencies. + + imp_dep_pkgs :: [PackageId], -- Packages needed by the module being compiled, whether -- directly, or via other modules in this package, or via -- modules imported from other packages. - imp_orphs :: [ModuleName] + imp_orphs :: [Module] -- Orphan modules below us in the import tree } +mkModDeps :: [(Module, IsBootInterface)] + -> ModuleEnv (Module, IsBootInterface) +mkModDeps deps = foldl add emptyModuleEnv deps + where + add env elt@(m,_) = extendModuleEnv env m elt + emptyImportAvails :: ImportAvails -emptyImportAvails = ImportAvails { imp_env = emptyAvailEnv, - imp_qual = emptyModuleEnv, +emptyImportAvails = ImportAvails { imp_env = emptyModuleEnv, imp_mods = emptyModuleEnv, imp_dep_mods = emptyModuleEnv, imp_dep_pkgs = [], @@ -534,12 +514,11 @@ emptyImportAvails = ImportAvails { imp_env = emptyAvailEnv, plusImportAvails :: ImportAvails -> ImportAvails -> ImportAvails plusImportAvails - (ImportAvails { imp_env = env1, imp_qual = unqual1, imp_mods = mods1, + (ImportAvails { imp_env = env1, imp_mods = mods1, imp_dep_mods = dmods1, imp_dep_pkgs = dpkgs1, imp_orphs = orphs1 }) - (ImportAvails { imp_env = env2, imp_qual = unqual2, imp_mods = mods2, + (ImportAvails { imp_env = env2, imp_mods = mods2, imp_dep_mods = dmods2, imp_dep_pkgs = dpkgs2, imp_orphs = orphs2 }) - = ImportAvails { imp_env = env1 `plusAvailEnv` env2, - imp_qual = plusModuleEnv_C plusAvailEnv unqual1 unqual2, + = ImportAvails { imp_env = plusModuleEnv_C unionNameSets env1 env2, imp_mods = mods1 `plusModuleEnv` mods2, imp_dep_mods = plusModuleEnv_C plus_mod_dep dmods1 dmods2, imp_dep_pkgs = dpkgs1 `unionLists` dpkgs2, @@ -597,7 +576,13 @@ unitAvailEnv a = unitNameEnv (availName a) a plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv plusAvailEnv = plusNameEnv_C plusAvail -lookupAvailEnv = lookupNameEnv +lookupAvailEnv_maybe :: AvailEnv -> Name -> Maybe AvailInfo +lookupAvailEnv_maybe = lookupNameEnv + +lookupAvailEnv :: AvailEnv -> Name -> AvailInfo +lookupAvailEnv env n = case lookupNameEnv env n of + Just avail -> avail + Nothing -> pprPanic "lookupAvailEnv" (ppr n) availEnvElts = nameEnvElts @@ -623,17 +608,11 @@ The @WhereFrom@ type controls where the renamer looks for an interface file \begin{code} data WhereFrom = ImportByUser IsBootInterface -- Ordinary user import (perhaps {-# SOURCE #-}) - - | ImportForUsage IsBootInterface -- Import when chasing usage info from an interaface file - -- Failure in this case is not an error - | ImportBySystem -- Non user import. instance Outputable WhereFrom where ppr (ImportByUser is_boot) | is_boot = ptext SLIT("{- SOURCE -}") | otherwise = empty - ppr (ImportForUsage is_boot) | is_boot = ptext SLIT("{- USAGE SOURCE -}") - | otherwise = ptext SLIT("{- USAGE -}") ppr ImportBySystem = ptext SLIT("{- SYSTEM -}") \end{code} @@ -655,7 +634,7 @@ type Int, represented by \begin{code} data Inst = Dict - Id + Name TcPredType InstLoc @@ -684,13 +663,13 @@ data Inst -- type of (f tys dicts(from theta)) = tau -- INVARIANT 2: tau must not be of form (Pred -> Tau) - -- Reason: two methods are considerd equal if the + -- Reason: two methods are considered equal if the -- base Id matches, and the instantiating types -- match. The TcThetaType should then match too. -- This only bites in the call to tcInstClassOp in TcClassDcl.mkMethodBind | LitInst - Id + Name HsOverLit -- The literal from the occurrence site -- INVARIANT: never a rebindable-syntax literal -- Reason: tcSyntaxName does unification, and we @@ -760,107 +739,61 @@ It appears in TcMonad because there are a couple of error-message-generation functions that deal with it. \begin{code} -data InstLoc = InstLoc InstOrigin SrcLoc ErrCtxt +data InstLoc = InstLoc InstOrigin SrcSpan ErrCtxt instLocSrcLoc :: InstLoc -> SrcLoc -instLocSrcLoc (InstLoc _ src_loc _) = src_loc +instLocSrcLoc (InstLoc _ src_span _) = srcSpanStart src_span -data InstOrigin - = OccurrenceOf Name -- Occurrence of an overloaded identifier +instLocSrcSpan :: InstLoc -> SrcSpan +instLocSrcSpan (InstLoc _ src_span _) = src_span - | IPOcc (IPName Name) -- Occurrence of an implicit parameter - | IPBind (IPName Name) -- Binding site of an implicit parameter +data InstOrigin + = SigOrigin SkolemInfo -- Pattern, class decl, inst decl etc; + -- Places that bind type variables and introduce + -- available constraints - | RecordUpdOrigin + | IPBindOrigin (IPName Name) -- Binding site of an implicit parameter - | DataDeclOrigin -- Typechecking a data declaration + ------------------------------------------------------- + -- The rest are all occurrences: Insts that are 'wanted' + ------------------------------------------------------- + | OccurrenceOf Name -- Occurrence of an overloaded identifier - | InstanceDeclOrigin -- Typechecking an instance decl + | IPOccOrigin (IPName Name) -- Occurrence of an implicit parameter | LiteralOrigin HsOverLit -- Occurrence of a literal - | PatOrigin RenamedPat - - | ArithSeqOrigin RenamedArithSeqInfo -- [x..], [x..y] etc - | PArrSeqOrigin RenamedArithSeqInfo -- [:x..y:] and [:x,y..z:] + | ArithSeqOrigin (ArithSeqInfo Name) -- [x..], [x..y] etc + | PArrSeqOrigin (ArithSeqInfo Name) -- [:x..y:] and [:x,y..z:] - | SignatureOrigin -- A dict created from a type signature - | Rank2Origin -- A dict created when typechecking the argument - -- of a rank-2 typed function + | InstSigOrigin -- A dict occurrence arising from instantiating + -- a polymorphic type during a subsumption check - | DoOrigin -- The monad for a do expression - - | ClassDeclOrigin -- Manufactured during a class decl - - | InstanceSpecOrigin Class -- in a SPECIALIZE instance pragma - Type - - -- When specialising instances the instance info attached to - -- each class is not yet ready, so we record it inside the - -- origin information. This is a bit of a hack, but it works - -- fine. (Patrick is to blame [WDP].) - - | ValSpecOrigin Name -- in a SPECIALIZE pragma for a value - - -- Argument or result of a ccall - -- Dictionaries with this origin aren't actually mentioned in the - -- translated term, and so need not be bound. Nor should they - -- be abstracted over. - - | CCallOrigin String -- CCall label - (Maybe RenamedHsExpr) -- Nothing if it's the result - -- Just arg, for an argument - - | LitLitOrigin String -- the litlit - - | UnknownOrigin -- Help! I give up... + | RecordUpdOrigin + | InstScOrigin -- Typechecking superclasses of an instance declaration + | DerivOrigin -- Typechecking deriving + | DefaultOrigin -- Typechecking a default decl + | DoOrigin -- Arising from a do expression + | ProcOrigin -- Arising from a proc expression \end{code} \begin{code} pprInstLoc :: InstLoc -> SDoc -pprInstLoc (InstLoc orig locn ctxt) +pprInstLoc (InstLoc orig locn _) = hsep [text "arising from", pp_orig orig, text "at", ppr locn] where - pp_orig (OccurrenceOf name) - = hsep [ptext SLIT("use of"), quotes (ppr name)] - pp_orig (IPOcc name) - = hsep [ptext SLIT("use of implicit parameter"), quotes (ppr name)] - pp_orig (IPBind name) - = hsep [ptext SLIT("binding for implicit parameter"), quotes (ppr name)] - pp_orig RecordUpdOrigin - = ptext SLIT("a record update") - pp_orig DataDeclOrigin - = ptext SLIT("the data type declaration") - pp_orig InstanceDeclOrigin - = ptext SLIT("the instance declaration") - pp_orig (LiteralOrigin lit) - = hsep [ptext SLIT("the literal"), quotes (ppr lit)] - pp_orig (PatOrigin pat) - = hsep [ptext SLIT("the pattern"), quotes (ppr pat)] - pp_orig (ArithSeqOrigin seq) - = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)] - pp_orig (PArrSeqOrigin seq) - = hsep [ptext SLIT("the parallel array sequence"), quotes (ppr seq)] - pp_orig (SignatureOrigin) - = ptext SLIT("a type signature") - pp_orig (Rank2Origin) - = ptext SLIT("a function with an overloaded argument type") - pp_orig (DoOrigin) - = ptext SLIT("a do statement") - pp_orig (ClassDeclOrigin) - = ptext SLIT("a class declaration") - pp_orig (InstanceSpecOrigin clas ty) - = hsep [text "a SPECIALIZE instance pragma; class", - quotes (ppr clas), text "type:", ppr ty] - pp_orig (ValSpecOrigin name) - = hsep [ptext SLIT("a SPECIALIZE user-pragma for"), quotes (ppr name)] - pp_orig (CCallOrigin clabel Nothing{-ccall result-}) - = hsep [ptext SLIT("the result of the _ccall_ to"), quotes (text clabel)] - pp_orig (CCallOrigin clabel (Just arg_expr)) - = hsep [ptext SLIT("an argument in the _ccall_ to"), quotes (text clabel) <> comma, - text "namely", quotes (ppr arg_expr)] - pp_orig (LitLitOrigin s) - = hsep [ptext SLIT("the ``literal-literal''"), quotes (text s)] - pp_orig (UnknownOrigin) - = ptext SLIT("...oops -- I don't know where the overloading came from!") + pp_orig (OccurrenceOf name) = hsep [ptext SLIT("use of"), quotes (ppr name)] + pp_orig (IPOccOrigin name) = hsep [ptext SLIT("use of implicit parameter"), quotes (ppr name)] + pp_orig (IPBindOrigin name) = hsep [ptext SLIT("binding for implicit parameter"), quotes (ppr name)] + pp_orig RecordUpdOrigin = ptext SLIT("a record update") + pp_orig (LiteralOrigin lit) = hsep [ptext SLIT("the literal"), quotes (ppr lit)] + pp_orig (ArithSeqOrigin seq) = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)] + pp_orig (PArrSeqOrigin seq) = hsep [ptext SLIT("the parallel array sequence"), quotes (ppr seq)] + pp_orig InstSigOrigin = ptext SLIT("instantiating a type signature") + pp_orig InstScOrigin = ptext SLIT("the superclasses of an instance declaration") + pp_orig DerivOrigin = ptext SLIT("the 'deriving' clause of a data type declaration") + pp_orig DefaultOrigin = ptext SLIT("a 'default' declaration") + pp_orig DoOrigin = ptext SLIT("a do statement") + pp_orig ProcOrigin = ptext SLIT("a proc expression") + pp_orig (SigOrigin info) = pprSkolInfo info \end{code}