{-# LANGUAGE CPP #-} {-# LANGUAGE DeriveFunctor #-} {-# LANGUAGE ExistentialQuantification #-} {-# LANGUAGE GeneralizedNewtypeDeriving #-} {- (c) The University of Glasgow 2006-2012 (c) The GRASP Project, Glasgow University, 1992-2002 -} -- | Various types used during typechecking. -- -- Please see "GHC.Tc.Utils.Monad" as well for operations on these types. You probably -- want to import it, instead of this module. -- -- All the monads exported here are built on top of the same IOEnv monad. The -- monad functions like a Reader monad in the way it passes the environment -- around. This is done to allow the environment to be manipulated in a stack -- like fashion when entering expressions... etc. -- -- For state that is global and should be returned at the end (e.g not part -- of the stack mechanism), you should use a TcRef (= IORef) to store them. module GHC.Tc.Types( TcRnIf, TcRn, TcM, RnM, IfM, IfL, IfG, -- The monad is opaque outside this module TcRef, -- The environment types Env(..), TcGblEnv(..), TcLclEnv(..), setLclEnvTcLevel, getLclEnvTcLevel, setLclEnvLoc, getLclEnvLoc, IfGblEnv(..), IfLclEnv(..), tcVisibleOrphanMods, -- Frontend types (shouldn't really be here) FrontendResult(..), -- Renamer types ErrCtxt, RecFieldEnv, pushErrCtxt, pushErrCtxtSameOrigin, ImportAvails(..), emptyImportAvails, plusImportAvails, WhereFrom(..), mkModDeps, modDepsElts, -- Typechecker types TcTypeEnv, TcBinderStack, TcBinder(..), TcTyThing(..), PromotionErr(..), IdBindingInfo(..), ClosedTypeId, RhsNames, IsGroupClosed(..), SelfBootInfo(..), tcTyThingCategory, pprTcTyThingCategory, peCategory, pprPECategory, CompleteMatch, CompleteMatches, -- Template Haskell ThStage(..), SpliceType(..), PendingStuff(..), topStage, topAnnStage, topSpliceStage, ThLevel, impLevel, outerLevel, thLevel, ForeignSrcLang(..), THDocs, DocLoc(..), -- Arrows ArrowCtxt(..), -- TcSigInfo TcSigFun, TcSigInfo(..), TcIdSigInfo(..), TcIdSigInst(..), TcPatSynInfo(..), isPartialSig, hasCompleteSig, -- Misc other types TcId, TcIdSet, NameShape(..), removeBindingShadowing, getPlatform, -- Constraint solver plugins TcPlugin(..), TcPluginResult(..), TcPluginSolver, TcPluginM, runTcPluginM, unsafeTcPluginTcM, getEvBindsTcPluginM, -- Role annotations RoleAnnotEnv, emptyRoleAnnotEnv, mkRoleAnnotEnv, lookupRoleAnnot, getRoleAnnots, -- Linting lintGblEnv ) where #include "HsVersions.h" import GHC.Prelude import GHC.Platform import GHC.Driver.Env import GHC.Driver.Session import {-# SOURCE #-} GHC.Driver.Hooks import GHC.Hs import GHC.Tc.Utils.TcType import GHC.Tc.Types.Constraint import GHC.Tc.Types.Origin import GHC.Tc.Types.Evidence import {-# SOURCE #-} GHC.Tc.Errors.Hole.FitTypes ( HoleFitPlugin ) import GHC.Core.Type import GHC.Core.TyCon ( TyCon, tyConKind ) import GHC.Core.PatSyn ( PatSyn ) import GHC.Core.Lint ( lintAxioms ) import GHC.Core.UsageEnv import GHC.Core.InstEnv import GHC.Core.FamInstEnv import GHC.Types.Id ( idType, idName ) import GHC.Types.FieldLabel ( FieldLabel ) import GHC.Types.Fixity.Env import GHC.Types.Annotations import GHC.Types.CompleteMatch import GHC.Types.Name.Reader import GHC.Types.Name import GHC.Types.Name.Env import GHC.Types.Name.Set import GHC.Types.Avail import GHC.Types.Var import GHC.Types.Var.Env import GHC.Types.TypeEnv import GHC.Types.TyThing import GHC.Types.SourceFile import GHC.Types.SrcLoc import GHC.Types.Var.Set import GHC.Types.Unique.FM import GHC.Types.Basic import GHC.Types.CostCentre.State import GHC.Types.HpcInfo import GHC.Data.IOEnv import GHC.Data.Bag import GHC.Data.List.SetOps import GHC.Unit import GHC.Unit.Module.Warnings import GHC.Unit.Module.Imported import GHC.Unit.Module.ModDetails import GHC.Utils.Error import GHC.Utils.Outputable import GHC.Utils.Fingerprint import GHC.Utils.Misc import GHC.Utils.Panic import GHC.Utils.Logger import GHC.Builtin.Names ( isUnboundName ) import Control.Monad (ap) import Data.Set ( Set ) import qualified Data.Set as S import Data.List ( sort ) import Data.Map ( Map ) import Data.Dynamic ( Dynamic ) import Data.Typeable ( TypeRep ) import Data.Maybe ( mapMaybe ) import GHCi.Message import GHCi.RemoteTypes import qualified Language.Haskell.TH as TH -- | A 'NameShape' is a substitution on 'Name's that can be used -- to refine the identities of a hole while we are renaming interfaces -- (see "GHC.Iface.Rename"). Specifically, a 'NameShape' for -- 'ns_module_name' @A@, defines a mapping from @{A.T}@ -- (for some 'OccName' @T@) to some arbitrary other 'Name'. -- -- The most intruiging thing about a 'NameShape', however, is -- how it's constructed. A 'NameShape' is *implied* by the -- exported 'AvailInfo's of the implementor of an interface: -- if an implementor of signature @\<H>@ exports @M.T@, you implicitly -- define a substitution from @{H.T}@ to @M.T@. So a 'NameShape' -- is computed from the list of 'AvailInfo's that are exported -- by the implementation of a module, or successively merged -- together by the export lists of signatures which are joining -- together. -- -- It's not the most obvious way to go about doing this, but it -- does seem to work! -- -- NB: Can't boot this and put it in NameShape because then we -- start pulling in too many DynFlags things. data NameShape = NameShape { NameShape -> ModuleName ns_mod_name :: ModuleName, NameShape -> [AvailInfo] ns_exports :: [AvailInfo], NameShape -> OccEnv Name ns_map :: OccEnv Name } {- ************************************************************************ * * Standard monad definition for TcRn All the combinators for the monad can be found in GHC.Tc.Utils.Monad * * ************************************************************************ The monad itself has to be defined here, because it is mentioned by ErrCtxt -} type TcRnIf a b = IOEnv (Env a b) type TcRn = TcRnIf TcGblEnv TcLclEnv -- Type inference type IfM lcl = TcRnIf IfGblEnv lcl -- Iface stuff type IfG = IfM () -- Top level type IfL = IfM IfLclEnv -- Nested -- TcRn is the type-checking and renaming monad: the main monad that -- most type-checking takes place in. The global environment is -- 'TcGblEnv', which tracks all of the top-level type-checking -- information we've accumulated while checking a module, while the -- local environment is 'TcLclEnv', which tracks local information as -- we move inside expressions. -- | Historical "renaming monad" (now it's just 'TcRn'). type RnM = TcRn -- | Historical "type-checking monad" (now it's just 'TcRn'). type TcM = TcRn -- We 'stack' these envs through the Reader like monad infrastructure -- as we move into an expression (although the change is focused in -- the lcl type). data Env gbl lcl = Env { forall gbl lcl. Env gbl lcl -> HscEnv env_top :: !HscEnv, -- Top-level stuff that never changes -- Includes all info about imported things -- BangPattern is to fix leak, see #15111 forall gbl lcl. Env gbl lcl -> Char env_um :: !Char, -- Mask for Uniques forall gbl lcl. Env gbl lcl -> gbl env_gbl :: gbl, -- Info about things defined at the top level -- of the module being compiled forall gbl lcl. Env gbl lcl -> lcl env_lcl :: lcl -- Nested stuff; changes as we go into } instance ContainsDynFlags (Env gbl lcl) where extractDynFlags :: Env gbl lcl -> DynFlags extractDynFlags Env gbl lcl env = HscEnv -> DynFlags hsc_dflags (forall gbl lcl. Env gbl lcl -> HscEnv env_top Env gbl lcl env) instance ContainsHooks (Env gbl lcl) where extractHooks :: Env gbl lcl -> Hooks extractHooks Env gbl lcl env = HscEnv -> Hooks hsc_hooks (forall gbl lcl. Env gbl lcl -> HscEnv env_top Env gbl lcl env) instance ContainsLogger (Env gbl lcl) where extractLogger :: Env gbl lcl -> Logger extractLogger Env gbl lcl env = HscEnv -> Logger hsc_logger (forall gbl lcl. Env gbl lcl -> HscEnv env_top Env gbl lcl env) instance ContainsModule gbl => ContainsModule (Env gbl lcl) where extractModule :: Env gbl lcl -> Module extractModule Env gbl lcl env = forall t. ContainsModule t => t -> Module extractModule (forall gbl lcl. Env gbl lcl -> gbl env_gbl Env gbl lcl env) {- ************************************************************************ * * The interface environments Used when dealing with IfaceDecls * * ************************************************************************ -} data IfGblEnv = IfGblEnv { -- Some information about where this environment came from; -- useful for debugging. IfGblEnv -> SDoc if_doc :: SDoc, -- 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. -- See Note [Tying the knot] in GHC.IfaceToCore IfGblEnv -> Maybe (Module, IfG TypeEnv) 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 -- NB: This is a semantic module, see -- Note [Identity versus semantic module] IfLclEnv -> Module if_mod :: Module, -- Whether or not the IfaceDecl came from a boot -- file or not; we'll use this to choose between -- NoUnfolding and BootUnfolding IfLclEnv -> IsBootInterface if_boot :: IsBootInterface, -- The field is used only for error reporting -- if (say) there's a Lint error in it IfLclEnv -> SDoc if_loc :: SDoc, -- Where the interface came from: -- .hi file, or GHCi state, or ext core -- plus which bit is currently being examined IfLclEnv -> Maybe NameShape if_nsubst :: Maybe NameShape, -- This field is used to make sure "implicit" declarations -- (anything that cannot be exported in mi_exports) get -- wired up correctly in typecheckIfacesForMerging. Most -- of the time it's @Nothing@. See Note [Resolving never-exported Names] -- in GHC.IfaceToCore. IfLclEnv -> Maybe TypeEnv if_implicits_env :: Maybe TypeEnv, IfLclEnv -> FastStringEnv TyVar if_tv_env :: FastStringEnv TyVar, -- Nested tyvar bindings IfLclEnv -> FastStringEnv TyVar if_id_env :: FastStringEnv Id -- Nested id binding } {- ************************************************************************ * * Global typechecker environment * * ************************************************************************ -} -- | 'FrontendResult' describes the result of running the frontend of a Haskell -- module. Currently one always gets a 'FrontendTypecheck', since running the -- frontend involves typechecking a program. hs-sig merges are not handled here. -- -- This data type really should be in GHC.Driver.Env, but it needs -- to have a TcGblEnv which is only defined here. data FrontendResult = FrontendTypecheck TcGblEnv -- Note [Identity versus semantic module] -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- When typechecking an hsig file, it is convenient to keep track -- of two different "this module" identifiers: -- -- - The IDENTITY module is simply thisPackage + the module -- name; i.e. it uniquely *identifies* the interface file -- we're compiling. For example, p[A=<A>]:A is an -- identity module identifying the requirement named A -- from library p. -- -- - The SEMANTIC module, which is the actual module that -- this signature is intended to represent (e.g. if -- we have a identity module p[A=base:Data.IORef]:A, -- then the semantic module is base:Data.IORef) -- -- Which one should you use? -- -- - In the desugarer and later phases of compilation, -- identity and semantic modules coincide, since we never compile -- signatures (we just generate blank object files for -- hsig files.) -- -- A corrolary of this is that the following invariant holds at any point -- past desugaring, -- -- if I have a Module, this_mod, in hand representing the module -- currently being compiled, -- then moduleUnit this_mod == thisPackage dflags -- -- - For any code involving Names, we want semantic modules. -- See lookupIfaceTop in GHC.Iface.Env, mkIface and addFingerprints -- in GHC.Iface.{Make,Recomp}, and tcLookupGlobal in GHC.Tc.Utils.Env -- -- - When reading interfaces, we want the identity module to -- identify the specific interface we want (such interfaces -- should never be loaded into the EPS). However, if a -- hole module <A> is requested, we look for A.hi -- in the home library we are compiling. (See GHC.Iface.Load.) -- Similarly, in GHC.Rename.Names we check for self-imports using -- identity modules, to allow signatures to import their implementor. -- -- - For recompilation avoidance, you want the identity module, -- since that will actually say the specific interface you -- want to track (and recompile if it changes) -- | 'TcGblEnv' describes the top-level of the module at the -- point at which the typechecker is finished work. -- It is this structure that is handed on to the desugarer -- For state that needs to be updated during the typechecking -- phase and returned at end, use a 'TcRef' (= 'IORef'). data TcGblEnv = TcGblEnv { TcGblEnv -> Module tcg_mod :: Module, -- ^ Module being compiled TcGblEnv -> Module tcg_semantic_mod :: Module, -- ^ If a signature, the backing module -- See also Note [Identity versus semantic module] TcGblEnv -> HscSource tcg_src :: HscSource, -- ^ What kind of module (regular Haskell, hs-boot, hsig) TcGblEnv -> GlobalRdrEnv tcg_rdr_env :: GlobalRdrEnv, -- ^ Top level envt; used during renaming TcGblEnv -> Maybe [Type] tcg_default :: Maybe [Type], -- ^ Types used for defaulting. @Nothing@ => no @default@ decl TcGblEnv -> FixityEnv tcg_fix_env :: FixityEnv, -- ^ Just for things in this module TcGblEnv -> RecFieldEnv tcg_field_env :: RecFieldEnv, -- ^ Just for things in this module -- See Note [The interactive package] in "GHC.Runtime.Context" TcGblEnv -> TypeEnv 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, -- along with their derived constructors, selectors. -- -- (Ids defined in this module start in the local envt, though they -- move to the global envt during zonking) -- -- NB: for what "things in this module" means, see -- Note [The interactive package] in "GHC.Runtime.Context" TcGblEnv -> TcRef TypeEnv 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) TcGblEnv -> InstEnv tcg_inst_env :: !InstEnv, -- ^ Instance envt for all /home-package/ modules; -- Includes the dfuns in tcg_insts -- NB. BangPattern is to fix a leak, see #15111 TcGblEnv -> FamInstEnv tcg_fam_inst_env :: !FamInstEnv, -- ^ Ditto for family instances -- NB. BangPattern is to fix a leak, see #15111 TcGblEnv -> AnnEnv tcg_ann_env :: AnnEnv, -- ^ And for annotations -- 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. TcGblEnv -> [AvailInfo] tcg_exports :: [AvailInfo], -- ^ What is exported TcGblEnv -> ImportAvails tcg_imports :: ImportAvails, -- ^ Information about what was imported from where, including -- things bound in this module. Also store Safe Haskell info -- here about transitive trusted package requirements. -- -- There are not many uses of this field, so you can grep for -- all them. -- -- The ImportAvails records information about the following -- things: -- -- 1. All of the modules you directly imported (tcRnImports) -- 2. The orphans (only!) of all imported modules in a GHCi -- session (runTcInteractive) -- 3. The module that instantiated a signature -- 4. Each of the signatures that merged in -- -- It is used in the following ways: -- - imp_orphs is used to determine what orphan modules should be -- visible in the context (tcVisibleOrphanMods) -- - imp_finsts is used to determine what family instances should -- be visible (tcExtendLocalFamInstEnv) -- - To resolve the meaning of the export list of a module -- (tcRnExports) -- - imp_mods is used to compute usage info (mkIfaceTc, deSugar) -- - imp_trust_own_pkg is used for Safe Haskell in interfaces -- (mkIfaceTc, as well as in "GHC.Driver.Main") -- - To create the Dependencies field in interface (mkDependencies) -- These three fields track unused bindings and imports -- See Note [Tracking unused binding and imports] TcGblEnv -> DefUses tcg_dus :: DefUses, TcGblEnv -> TcRef [GlobalRdrElt] tcg_used_gres :: TcRef [GlobalRdrElt], TcGblEnv -> TcRef NameSet tcg_keep :: TcRef NameSet, TcGblEnv -> TcRef Bool 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, because the desugarer is going -- to emit loads of references to TH symbols. The reference -- is implicit rather than explicit, so we have to zap a -- mutable variable. TcGblEnv -> TcRef Bool tcg_th_splice_used :: TcRef Bool, -- ^ @True@ \<=> A Template Haskell splice was used. -- -- Splices disable recompilation avoidance (see #481) TcGblEnv -> TcRef OccSet tcg_dfun_n :: TcRef OccSet, -- ^ Allows us to choose unique DFun names. TcGblEnv -> [(Module, Fingerprint)] tcg_merged :: [(Module, Fingerprint)], -- ^ The requirements we merged with; we always have to recompile -- if any of these changed. -- The next fields accumulate the payload of the module -- The binds, rules and foreign-decl fields are collected -- initially in un-zonked form and are finally zonked in tcRnSrcDecls TcGblEnv -> Maybe [(LIE GhcRn, [AvailInfo])] tcg_rn_exports :: Maybe [(LIE GhcRn, Avails)], -- Nothing <=> no explicit export list -- Is always Nothing if we don't want to retain renamed -- exports. -- If present contains each renamed export list item -- together with its exported names. TcGblEnv -> [LImportDecl GhcRn] tcg_rn_imports :: [LImportDecl GhcRn], -- Keep the renamed imports regardless. They are not -- voluminous and are needed if you want to report unused imports TcGblEnv -> Maybe (HsGroup GhcRn) tcg_rn_decls :: Maybe (HsGroup GhcRn), -- ^ Renamed decls, maybe. @Nothing@ \<=> Don't retain renamed -- decls. TcGblEnv -> TcRef [FilePath] tcg_dependent_files :: TcRef [FilePath], -- ^ dependencies from addDependentFile TcGblEnv -> TcRef [LHsDecl GhcPs] tcg_th_topdecls :: TcRef [LHsDecl GhcPs], -- ^ Top-level declarations from addTopDecls TcGblEnv -> TcRef [(ForeignSrcLang, FilePath)] tcg_th_foreign_files :: TcRef [(ForeignSrcLang, FilePath)], -- ^ Foreign files emitted from TH. TcGblEnv -> TcRef NameSet tcg_th_topnames :: TcRef NameSet, -- ^ Exact names bound in top-level declarations in tcg_th_topdecls TcGblEnv -> TcRef [(TcLclEnv, ThModFinalizers)] tcg_th_modfinalizers :: TcRef [(TcLclEnv, ThModFinalizers)], -- ^ Template Haskell module finalizers. -- -- They can use particular local environments. TcGblEnv -> TcRef [FilePath] tcg_th_coreplugins :: TcRef [String], -- ^ Core plugins added by Template Haskell code. TcGblEnv -> TcRef (Map TypeRep Dynamic) tcg_th_state :: TcRef (Map TypeRep Dynamic), TcGblEnv -> TcRef (Maybe (ForeignRef (IORef QState))) tcg_th_remote_state :: TcRef (Maybe (ForeignRef (IORef QState))), -- ^ Template Haskell state TcGblEnv -> TcRef THDocs tcg_th_docs :: TcRef THDocs, -- ^ Docs added in Template Haskell via @putDoc@. TcGblEnv -> Bag EvBind tcg_ev_binds :: Bag EvBind, -- Top-level evidence bindings -- Things defined in this module, or (in GHCi) -- in the declarations for a single GHCi command. -- For the latter, see Note [The interactive package] in -- GHC.Runtime.Context TcGblEnv -> Maybe TyVar tcg_tr_module :: Maybe Id, -- Id for $trModule :: GHC.Unit.Module -- for which every module has a top-level defn -- except in GHCi in which case we have Nothing TcGblEnv -> LHsBinds GhcTc tcg_binds :: LHsBinds GhcTc, -- Value bindings in this module TcGblEnv -> NameSet tcg_sigs :: NameSet, -- ...Top-level names that *lack* a signature TcGblEnv -> [LTcSpecPrag] tcg_imp_specs :: [LTcSpecPrag], -- ...SPECIALISE prags for imported Ids TcGblEnv -> Warnings tcg_warns :: Warnings, -- ...Warnings and deprecations TcGblEnv -> [Annotation] tcg_anns :: [Annotation], -- ...Annotations TcGblEnv -> [TyCon] tcg_tcs :: [TyCon], -- ...TyCons and Classes TcGblEnv -> NameSet tcg_ksigs :: NameSet, -- ...Top-level TyCon names that *lack* a signature TcGblEnv -> [ClsInst] tcg_insts :: [ClsInst], -- ...Instances TcGblEnv -> [FamInst] tcg_fam_insts :: [FamInst], -- ...Family instances TcGblEnv -> [LRuleDecl GhcTc] tcg_rules :: [LRuleDecl GhcTc], -- ...Rules TcGblEnv -> [LForeignDecl GhcTc] tcg_fords :: [LForeignDecl GhcTc], -- ...Foreign import & exports TcGblEnv -> [PatSyn] tcg_patsyns :: [PatSyn], -- ...Pattern synonyms TcGblEnv -> Maybe LHsDocString tcg_doc_hdr :: Maybe LHsDocString, -- ^ Maybe Haddock header docs TcGblEnv -> Bool tcg_hpc :: !AnyHpcUsage, -- ^ @True@ if any part of the -- prog uses hpc instrumentation. -- NB. BangPattern is to fix a leak, see #15111 TcGblEnv -> SelfBootInfo tcg_self_boot :: SelfBootInfo, -- ^ Whether this module has a -- corresponding hi-boot file TcGblEnv -> Maybe Name tcg_main :: Maybe Name, -- ^ The Name of the main -- function, if this module is -- the main module. TcGblEnv -> TcRef (Bool, WarningMessages) tcg_safeInfer :: TcRef (Bool, WarningMessages), -- ^ Has the typechecker inferred this module as -XSafe (Safe Haskell) -- See Note [Safe Haskell Overlapping Instances Implementation], -- although this is used for more than just that failure case. TcGblEnv -> [TcPluginSolver] tcg_tc_plugins :: [TcPluginSolver], -- ^ A list of user-defined plugins for the constraint solver. TcGblEnv -> [HoleFitPlugin] tcg_hf_plugins :: [HoleFitPlugin], -- ^ A list of user-defined plugins for hole fit suggestions. TcGblEnv -> RealSrcSpan tcg_top_loc :: RealSrcSpan, -- ^ The RealSrcSpan this module came from TcGblEnv -> TcRef WantedConstraints tcg_static_wc :: TcRef WantedConstraints, -- ^ Wanted constraints of static forms. -- See Note [Constraints in static forms]. TcGblEnv -> CompleteMatches tcg_complete_matches :: !CompleteMatches, -- ^ Tracking indices for cost centre annotations TcGblEnv -> TcRef CostCentreState tcg_cc_st :: TcRef CostCentreState } -- NB: topModIdentity, not topModSemantic! -- Definition sites of orphan identities will be identity modules, not semantic -- modules. -- Note [Constraints in static forms] -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- -- When a static form produces constraints like -- -- f :: StaticPtr (Bool -> String) -- f = static show -- -- we collect them in tcg_static_wc and resolve them at the end -- of type checking. They need to be resolved separately because -- we don't want to resolve them in the context of the enclosing -- expression. Consider -- -- g :: Show a => StaticPtr (a -> String) -- g = static show -- -- If the @Show a0@ constraint that the body of the static form produces was -- resolved in the context of the enclosing expression, then the body of the -- static form wouldn't be closed because the Show dictionary would come from -- g's context instead of coming from the top level. tcVisibleOrphanMods :: TcGblEnv -> ModuleSet tcVisibleOrphanMods :: TcGblEnv -> ModuleSet tcVisibleOrphanMods TcGblEnv tcg_env = [Module] -> ModuleSet mkModuleSet (TcGblEnv -> Module tcg_mod TcGblEnv tcg_env forall a. a -> [a] -> [a] : ImportAvails -> [Module] imp_orphs (TcGblEnv -> ImportAvails tcg_imports TcGblEnv tcg_env)) instance ContainsModule TcGblEnv where extractModule :: TcGblEnv -> Module extractModule TcGblEnv env = TcGblEnv -> Module tcg_semantic_mod TcGblEnv env type RecFieldEnv = NameEnv [FieldLabel] -- Maps a constructor name *in this module* -- to the fields for that constructor. -- This is used when dealing with ".." notation in record -- construction and pattern matching. -- The FieldEnv deals *only* with constructors defined in *this* -- module. For imported modules, we get the same info from the -- TypeEnv data SelfBootInfo = NoSelfBoot -- No corresponding hi-boot file | SelfBoot { SelfBootInfo -> ModDetails sb_mds :: ModDetails -- There was a hi-boot file, , SelfBootInfo -> NameSet sb_tcs :: NameSet } -- defining these TyCons, -- What is sb_tcs used for? See Note [Extra dependencies from .hs-boot files] -- in GHC.Rename.Module {- Note [Tracking unused binding and imports] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We gather three sorts of usage information * tcg_dus :: DefUses (defs/uses) Records what is defined in this module and what is used. Records *defined* Names (local, top-level) and *used* Names (local or imported) Used (a) to report "defined but not used" (see GHC.Rename.Names.reportUnusedNames) (b) to generate version-tracking usage info in interface files (see GHC.Iface.Make.mkUsedNames) This usage info is mainly gathered by the renamer's gathering of free-variables * tcg_used_gres :: TcRef [GlobalRdrElt] Records occurrences of imported entities. Used only to report unused import declarations Records each *occurrence* an *imported* (not locally-defined) entity. The occurrence is recorded by keeping a GlobalRdrElt for it. These is not the GRE that is in the GlobalRdrEnv; rather it is recorded *after* the filtering done by pickGREs. So it reflect /how that occurrence is in scope/. See Note [GRE filtering] in RdrName. * tcg_keep :: TcRef NameSet Records names of the type constructors, data constructors, and Ids that are used by the constraint solver. The typechecker may use find that some imported or locally-defined things are used, even though they do not appear to be mentioned in the source code: (a) The to/from functions for generic data types (b) Top-level variables appearing free in the RHS of an orphan rule (c) Top-level variables appearing free in a TH bracket See Note [Keeping things alive for Template Haskell] in GHC.Rename.Splice (d) The data constructor of a newtype that is used to solve a Coercible instance (e.g. #10347). Example module T10347 (N, mkN) where import Data.Coerce newtype N a = MkN Int mkN :: Int -> N a mkN = coerce Then we wish to record `MkN` as used, since it is (morally) used to perform the coercion in `mkN`. To do so, the Coercible solver updates tcg_keep's TcRef whenever it encounters a use of `coerce` that crosses newtype boundaries. (e) Record fields that are used to solve HasField constraints (see Note [Unused name reporting and HasField] in GHC.Tc.Instance.Class) The tcg_keep field is used in two distinct ways: * Desugar.addExportFlagsAndRules. Where things like (a-c) are locally defined, we should 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). * GHC.Rename.Names.reportUnusedNames. Where newtype data constructors like (d) are imported, we don't want to report them as unused. ************************************************************************ * * The local typechecker environment * * ************************************************************************ Note [The Global-Env/Local-Env story] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ During type checking, we keep in the tcg_type_env * All types and classes * All Ids derived from types and classes (constructors, selectors) At the end of type checking, we zonk the local bindings, and as we do so we add to the tcg_type_env * Locally defined top-level Ids Why? Because they are now Ids not TcIds. This final GlobalEnv is a) fed back (via the knot) to typechecking the unfoldings of interface signatures b) used in the ModDetails of this module -} data TcLclEnv -- Changes as we move inside an expression -- Discarded after typecheck/rename; not passed on to desugarer = TcLclEnv { TcLclEnv -> RealSrcSpan tcl_loc :: RealSrcSpan, -- Source span TcLclEnv -> [ErrCtxt] tcl_ctxt :: [ErrCtxt], -- Error context, innermost on top TcLclEnv -> Bool tcl_in_gen_code :: Bool, -- See Note [Rebindable syntax and HsExpansion] TcLclEnv -> TcLevel tcl_tclvl :: TcLevel, TcLclEnv -> ThStage tcl_th_ctxt :: ThStage, -- Template Haskell context TcLclEnv -> ThBindEnv tcl_th_bndrs :: ThBindEnv, -- and binder info -- The ThBindEnv records the TH binding level of in-scope Names -- defined in this module (not imported) -- We can't put this info in the TypeEnv because it's needed -- (and extended) in the renamer, for untyed splices TcLclEnv -> ArrowCtxt tcl_arrow_ctxt :: ArrowCtxt, -- Arrow-notation context TcLclEnv -> LocalRdrEnv 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 constructor (Name.TvOcc) -- We still need the unsullied global name env so that -- we can look up record field names TcLclEnv -> TcTypeEnv tcl_env :: TcTypeEnv, -- The local type environment: -- Ids and TyVars defined in this module TcLclEnv -> TcRef UsageEnv tcl_usage :: TcRef UsageEnv, -- Required multiplicity of bindings is accumulated here. TcLclEnv -> TcBinderStack tcl_bndrs :: TcBinderStack, -- Used for reporting relevant bindings, -- and for tidying types TcLclEnv -> TcRef WantedConstraints tcl_lie :: TcRef WantedConstraints, -- Place to accumulate type constraints TcLclEnv -> TcRef (Messages DecoratedSDoc) tcl_errs :: TcRef (Messages DecoratedSDoc) -- Place to accumulate errors } setLclEnvTcLevel :: TcLclEnv -> TcLevel -> TcLclEnv setLclEnvTcLevel :: TcLclEnv -> TcLevel -> TcLclEnv setLclEnvTcLevel TcLclEnv env TcLevel lvl = TcLclEnv env { tcl_tclvl :: TcLevel tcl_tclvl = TcLevel lvl } getLclEnvTcLevel :: TcLclEnv -> TcLevel getLclEnvTcLevel :: TcLclEnv -> TcLevel getLclEnvTcLevel = TcLclEnv -> TcLevel tcl_tclvl setLclEnvLoc :: TcLclEnv -> RealSrcSpan -> TcLclEnv setLclEnvLoc :: TcLclEnv -> RealSrcSpan -> TcLclEnv setLclEnvLoc TcLclEnv env RealSrcSpan loc = TcLclEnv env { tcl_loc :: RealSrcSpan tcl_loc = RealSrcSpan loc } getLclEnvLoc :: TcLclEnv -> RealSrcSpan getLclEnvLoc :: TcLclEnv -> RealSrcSpan getLclEnvLoc = TcLclEnv -> RealSrcSpan tcl_loc type ErrCtxt = (Bool, TidyEnv -> TcM (TidyEnv, SDoc)) -- Monadic so that we have a chance -- to deal with bound type variables just before error -- message construction -- Bool: True <=> this is a landmark context; do not -- discard it when trimming for display -- These are here to avoid module loops: one might expect them -- in GHC.Tc.Types.Constraint, but they refer to ErrCtxt which refers to TcM. -- Easier to just keep these definitions here, alongside TcM. pushErrCtxt :: CtOrigin -> ErrCtxt -> CtLoc -> CtLoc pushErrCtxt :: CtOrigin -> ErrCtxt -> CtLoc -> CtLoc pushErrCtxt CtOrigin o ErrCtxt err loc :: CtLoc loc@(CtLoc { ctl_env :: CtLoc -> TcLclEnv ctl_env = TcLclEnv lcl }) = CtLoc loc { ctl_origin :: CtOrigin ctl_origin = CtOrigin o, ctl_env :: TcLclEnv ctl_env = TcLclEnv lcl { tcl_ctxt :: [ErrCtxt] tcl_ctxt = ErrCtxt err forall a. a -> [a] -> [a] : TcLclEnv -> [ErrCtxt] tcl_ctxt TcLclEnv lcl } } pushErrCtxtSameOrigin :: ErrCtxt -> CtLoc -> CtLoc -- Just add information w/o updating the origin! pushErrCtxtSameOrigin :: ErrCtxt -> CtLoc -> CtLoc pushErrCtxtSameOrigin ErrCtxt err loc :: CtLoc loc@(CtLoc { ctl_env :: CtLoc -> TcLclEnv ctl_env = TcLclEnv lcl }) = CtLoc loc { ctl_env :: TcLclEnv ctl_env = TcLclEnv lcl { tcl_ctxt :: [ErrCtxt] tcl_ctxt = ErrCtxt err forall a. a -> [a] -> [a] : TcLclEnv -> [ErrCtxt] tcl_ctxt TcLclEnv lcl } } type TcTypeEnv = NameEnv TcTyThing type ThBindEnv = NameEnv (TopLevelFlag, ThLevel) -- Domain = all Ids bound in this module (ie not imported) -- The TopLevelFlag tells if the binding is syntactically top level. -- We need to know this, because the cross-stage persistence story allows -- cross-stage at arbitrary types if the Id is bound at top level. -- -- Nota bene: a ThLevel of 'outerLevel' is *not* the same as being -- bound at top level! See Note [Template Haskell levels] in GHC.Tc.Gen.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. -} -- | Type alias for 'IORef'; the convention is we'll use this for mutable -- bits of data in 'TcGblEnv' which are updated during typechecking and -- returned at the end. type TcRef a = IORef a -- ToDo: when should I refer to it as a 'TcId' instead of an 'Id'? type TcId = Id type TcIdSet = IdSet --------------------------- -- The TcBinderStack --------------------------- type TcBinderStack = [TcBinder] -- This is a stack of locally-bound ids and tyvars, -- innermost on top -- Used only in error reporting (relevantBindings in TcError), -- and in tidying -- We can't use the tcl_env type environment, because it doesn't -- keep track of the nesting order data TcBinder = TcIdBndr TcId TopLevelFlag -- Tells whether the binding is syntactically top-level -- (The monomorphic Ids for a recursive group count -- as not-top-level for this purpose.) | TcIdBndr_ExpType -- Variant that allows the type to be specified as -- an ExpType Name ExpType TopLevelFlag | TcTvBndr -- e.g. case x of P (y::a) -> blah Name -- We bind the lexical name "a" to the type of y, TyVar -- which might be an utterly different (perhaps -- existential) tyvar instance Outputable TcBinder where ppr :: TcBinder -> SDoc ppr (TcIdBndr TyVar id TopLevelFlag top_lvl) = forall a. Outputable a => a -> SDoc ppr TyVar id SDoc -> SDoc -> SDoc <> SDoc -> SDoc brackets (forall a. Outputable a => a -> SDoc ppr TopLevelFlag top_lvl) ppr (TcIdBndr_ExpType Name id ExpType _ TopLevelFlag top_lvl) = forall a. Outputable a => a -> SDoc ppr Name id SDoc -> SDoc -> SDoc <> SDoc -> SDoc brackets (forall a. Outputable a => a -> SDoc ppr TopLevelFlag top_lvl) ppr (TcTvBndr Name name TyVar tv) = forall a. Outputable a => a -> SDoc ppr Name name SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr TyVar tv instance HasOccName TcBinder where occName :: TcBinder -> OccName occName (TcIdBndr TyVar id TopLevelFlag _) = forall name. HasOccName name => name -> OccName occName (TyVar -> Name idName TyVar id) occName (TcIdBndr_ExpType Name name ExpType _ TopLevelFlag _) = forall name. HasOccName name => name -> OccName occName Name name occName (TcTvBndr Name name TyVar _) = forall name. HasOccName name => name -> OccName occName Name name -- fixes #12177 -- Builds up a list of bindings whose OccName has not been seen before -- i.e., If ys = removeBindingShadowing xs -- then -- - ys is obtained from xs by deleting some elements -- - ys has no duplicate OccNames -- - The first duplicated OccName in xs is retained in ys -- Overloaded so that it can be used for both GlobalRdrElt in typed-hole -- substitutions and TcBinder when looking for relevant bindings. removeBindingShadowing :: HasOccName a => [a] -> [a] removeBindingShadowing :: forall a. HasOccName a => [a] -> [a] removeBindingShadowing [a] bindings = forall a. [a] -> [a] reverse forall a b. (a -> b) -> a -> b $ forall a b. (a, b) -> a fst forall a b. (a -> b) -> a -> b $ forall (t :: * -> *) b a. Foldable t => (b -> a -> b) -> b -> t a -> b foldl (\([a] bindingAcc, OccSet seenNames) a binding -> if forall name. HasOccName name => name -> OccName occName a binding OccName -> OccSet -> Bool `elemOccSet` OccSet seenNames -- if we've seen it then ([a] bindingAcc, OccSet seenNames) -- skip it else (a bindingforall a. a -> [a] -> [a] :[a] bindingAcc, OccSet -> OccName -> OccSet extendOccSet OccSet seenNames (forall name. HasOccName name => name -> OccName occName a binding))) ([], OccSet emptyOccSet) [a] bindings -- | Get target platform getPlatform :: TcM Platform getPlatform :: TcM Platform getPlatform = DynFlags -> Platform targetPlatform forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b <$> forall (m :: * -> *). HasDynFlags m => m DynFlags getDynFlags --------------------------- -- Template Haskell stages and levels --------------------------- data SpliceType = Typed | Untyped data ThStage -- See Note [Template Haskell state diagram] -- and Note [Template Haskell levels] in GHC.Tc.Gen.Splice -- Start at: Comp -- At bracket: wrap current stage in Brack -- At splice: currently Brack: return to previous stage -- currently Comp/Splice: compile and run = Splice SpliceType -- Inside a top-level splice -- This code will be run *at compile time*; -- the result replaces the splice -- Binding level = 0 | RunSplice (TcRef [ForeignRef (TH.Q ())]) -- Set when running a splice, i.e. NOT when renaming or typechecking the -- Haskell code for the splice. See Note [RunSplice ThLevel]. -- -- Contains a list of mod finalizers collected while executing the splice. -- -- 'addModFinalizer' inserts finalizers here, and from here they are taken -- to construct an @HsSpliced@ annotation for untyped splices. See Note -- [Delaying modFinalizers in untyped splices] in GHC.Rename.Splice. -- -- For typed splices, the typechecker takes finalizers from here and -- inserts them in the list of finalizers in the global environment. -- -- See Note [Collecting modFinalizers in typed splices] in "GHC.Tc.Gen.Splice". | Comp -- Ordinary Haskell code -- Binding level = 1 | Brack -- Inside brackets ThStage -- Enclosing stage PendingStuff data PendingStuff = RnPendingUntyped -- Renaming the inside of an *untyped* bracket (TcRef [PendingRnSplice]) -- Pending splices in here | RnPendingTyped -- Renaming the inside of a *typed* bracket | TcPending -- Typechecking the inside of a typed bracket (TcRef [PendingTcSplice]) -- Accumulate pending splices here (TcRef WantedConstraints) -- and type constraints here QuoteWrapper -- A type variable and evidence variable -- for the overall monad of -- the bracket. Splices are checked -- against this monad. The evidence -- variable is used for desugaring -- `lift`. topStage, topAnnStage, topSpliceStage :: ThStage topStage :: ThStage topStage = ThStage Comp topAnnStage :: ThStage topAnnStage = SpliceType -> ThStage Splice SpliceType Untyped topSpliceStage :: ThStage topSpliceStage = SpliceType -> ThStage Splice SpliceType Untyped instance Outputable ThStage where ppr :: ThStage -> SDoc ppr (Splice SpliceType _) = FilePath -> SDoc text FilePath "Splice" ppr (RunSplice TcRef [ForeignRef (Q ())] _) = FilePath -> SDoc text FilePath "RunSplice" ppr ThStage Comp = FilePath -> SDoc text FilePath "Comp" ppr (Brack ThStage s PendingStuff _) = FilePath -> SDoc text FilePath "Brack" SDoc -> SDoc -> SDoc <> SDoc -> SDoc parens (forall a. Outputable a => a -> SDoc ppr ThStage s) type ThLevel = Int -- NB: see Note [Template Haskell levels] in GHC.Tc.Gen.Splice -- Incremented when going inside a bracket, -- decremented when going inside a splice -- NB: ThLevel is one greater than the 'n' in Fig 2 of the -- original "Template meta-programming for Haskell" paper impLevel, outerLevel :: ThLevel impLevel :: ThLevel impLevel = ThLevel 0 -- Imported things; they can be used inside a top level splice outerLevel :: ThLevel outerLevel = ThLevel 1 -- Things defined outside brackets thLevel :: ThStage -> ThLevel thLevel :: ThStage -> ThLevel thLevel (Splice SpliceType _) = ThLevel 0 thLevel ThStage Comp = ThLevel 1 thLevel (Brack ThStage s PendingStuff _) = ThStage -> ThLevel thLevel ThStage s forall a. Num a => a -> a -> a + ThLevel 1 thLevel (RunSplice TcRef [ForeignRef (Q ())] _) = forall a. FilePath -> a panic FilePath "thLevel: called when running a splice" -- See Note [RunSplice ThLevel]. {- Node [RunSplice ThLevel] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'RunSplice' stage is set when executing a splice, and only when running a splice. In particular it is not set when the splice is renamed or typechecked. 'RunSplice' is needed to provide a reference where 'addModFinalizer' can insert the finalizer (see Note [Delaying modFinalizers in untyped splices]), and 'addModFinalizer' runs when doing Q things. Therefore, It doesn't make sense to set 'RunSplice' when renaming or typechecking the splice, where 'Splice', 'Brack' or 'Comp' are used instead. -} --------------------------- -- Arrow-notation context --------------------------- {- Note [Escaping the arrow scope] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In arrow notation, a variable bound by a proc (or enclosed let/kappa) is not in scope to the left of an arrow tail (-<) or the head of (|..|). 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 proc y -> (proc z -> e1) -< e2 Here, x and z are in scope in e1, but y is not. We implement this by recording the environment when passing a proc (using newArrowScope), and returning to that (using escapeArrowScope) on the left of -< and the head of (|..|). All this can be dealt with by the *renamer*. But the type checker needs to be involved too. Example (arrowfail001) class Foo a where foo :: a -> () data Bar = forall a. Foo a => Bar a get :: Bar -> () get = proc x -> case x of Bar a -> foo -< a Here the call of 'foo' gives rise to a (Foo a) constraint that should not be captured by the pattern match on 'Bar'. Rather it should join the constraints from further out. So we must capture the constraint bag from further out in the ArrowCtxt that we push inwards. -} data ArrowCtxt -- Note [Escaping the arrow scope] = NoArrowCtxt | ArrowCtxt LocalRdrEnv (TcRef WantedConstraints) --------------------------- -- TcTyThing --------------------------- -- | A typecheckable thing available in a local context. Could be -- 'AGlobal' 'TyThing', but also lexically scoped variables, etc. -- See "GHC.Tc.Utils.Env" for how to retrieve a 'TyThing' given a 'Name'. data TcTyThing = AGlobal TyThing -- Used only in the return type of a lookup | ATcId -- Ids defined in this module; may not be fully zonked { TcTyThing -> TyVar tct_id :: TcId , TcTyThing -> IdBindingInfo tct_info :: IdBindingInfo -- See Note [Meaning of IdBindingInfo] } | ATyVar Name TcTyVar -- See Note [Type variables in the type environment] | ATcTyCon TyCon -- Used temporarily, during kind checking, for the -- tycons and clases in this recursive group -- The TyCon is always a TcTyCon. Its kind -- can be a mono-kind or a poly-kind; in TcTyClsDcls see -- Note [Type checking recursive type and class declarations] | APromotionErr PromotionErr data PromotionErr = TyConPE -- TyCon used in a kind before we are ready -- data T :: T -> * where ... | ClassPE -- Ditto Class | FamDataConPE -- Data constructor for a data family -- See Note [AFamDataCon: not promoting data family constructors] -- in GHC.Tc.Utils.Env. | ConstrainedDataConPE PredType -- Data constructor with a non-equality context -- See Note [Don't promote data constructors with -- non-equality contexts] in GHC.Tc.Gen.HsType | PatSynPE -- Pattern synonyms -- See Note [Don't promote pattern synonyms] in GHC.Tc.Utils.Env | RecDataConPE -- Data constructor in a recursive loop -- See Note [Recursion and promoting data constructors] in GHC.Tc.TyCl | NoDataKindsTC -- -XDataKinds not enabled (for a tycon) | NoDataKindsDC -- -XDataKinds not enabled (for a datacon) instance Outputable TcTyThing where -- Debugging only ppr :: TcTyThing -> SDoc ppr (AGlobal TyThing g) = forall a. Outputable a => a -> SDoc ppr TyThing g ppr elt :: TcTyThing elt@(ATcId {}) = FilePath -> SDoc text FilePath "Identifier" SDoc -> SDoc -> SDoc <> SDoc -> SDoc brackets (forall a. Outputable a => a -> SDoc ppr (TcTyThing -> TyVar tct_id TcTyThing elt) SDoc -> SDoc -> SDoc <> SDoc dcolon SDoc -> SDoc -> SDoc <> forall a. Outputable a => a -> SDoc ppr (TyVar -> Type varType (TcTyThing -> TyVar tct_id TcTyThing elt)) SDoc -> SDoc -> SDoc <> SDoc comma SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr (TcTyThing -> IdBindingInfo tct_info TcTyThing elt)) ppr (ATyVar Name n TyVar tv) = FilePath -> SDoc text FilePath "Type variable" SDoc -> SDoc -> SDoc <+> SDoc -> SDoc quotes (forall a. Outputable a => a -> SDoc ppr Name n) SDoc -> SDoc -> SDoc <+> SDoc equals SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr TyVar tv SDoc -> SDoc -> SDoc <+> SDoc dcolon SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr (TyVar -> Type varType TyVar tv) ppr (ATcTyCon TyCon tc) = FilePath -> SDoc text FilePath "ATcTyCon" SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr TyCon tc SDoc -> SDoc -> SDoc <+> SDoc dcolon SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr (TyCon -> Type tyConKind TyCon tc) ppr (APromotionErr PromotionErr err) = FilePath -> SDoc text FilePath "APromotionErr" SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr PromotionErr err -- | IdBindingInfo describes how an Id is bound. -- -- It is used for the following purposes: -- a) for static forms in 'GHC.Tc.Gen.Expr.checkClosedInStaticForm' and -- b) to figure out when a nested binding can be generalised, -- in 'GHC.Tc.Gen.Bind.decideGeneralisationPlan'. -- data IdBindingInfo -- See Note [Meaning of IdBindingInfo and ClosedTypeId] = NotLetBound | ClosedLet | NonClosedLet RhsNames -- Used for (static e) checks only ClosedTypeId -- Used for generalisation checks -- and for (static e) checks -- | IsGroupClosed describes a group of mutually-recursive bindings data IsGroupClosed = IsGroupClosed (NameEnv RhsNames) -- Free var info for the RHS of each binding in the goup -- Used only for (static e) checks ClosedTypeId -- True <=> all the free vars of the group are -- imported or ClosedLet or -- NonClosedLet with ClosedTypeId=True. -- In particular, no tyvars, no NotLetBound type RhsNames = NameSet -- Names of variables, mentioned on the RHS of -- a definition, that are not Global or ClosedLet type ClosedTypeId = Bool -- See Note [Meaning of IdBindingInfo and ClosedTypeId] {- Note [Meaning of IdBindingInfo] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NotLetBound means that the Id is not let-bound (e.g. it is bound in a lambda-abstraction or in a case pattern) ClosedLet means that - The Id is let-bound, - Any free term variables are also Global or ClosedLet - Its type has no free variables (NB: a top-level binding subject to the MR might have free vars in its type) These ClosedLets can definitely be floated to top level; and we may need to do so for static forms. Property: ClosedLet is equivalent to NonClosedLet emptyNameSet True (NonClosedLet (fvs::RhsNames) (cl::ClosedTypeId)) means that - The Id is let-bound - The fvs::RhsNames contains the free names of the RHS, excluding Global and ClosedLet ones. - For the ClosedTypeId field see Note [Bindings with closed types] For (static e) to be valid, we need for every 'x' free in 'e', that x's binding is floatable to the top level. Specifically: * x's RhsNames must be empty * x's type has no free variables See Note [Grand plan for static forms] in "GHC.Iface.Tidy.StaticPtrTable". This test is made in GHC.Tc.Gen.Expr.checkClosedInStaticForm. Actually knowing x's RhsNames (rather than just its emptiness or otherwise) is just so we can produce better error messages Note [Bindings with closed types: ClosedTypeId] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Consider f x = let g ys = map not ys in ... Can we generalise 'g' under the OutsideIn algorithm? Yes, because all g's free variables are top-level; that is they themselves have no free type variables, and it is the type variables in the environment that makes things tricky for OutsideIn generalisation. Here's the invariant: If an Id has ClosedTypeId=True (in its IdBindingInfo), then the Id's type is /definitely/ closed (has no free type variables). Specifically, a) The Id's actual type is closed (has no free tyvars) b) Either the Id has a (closed) user-supplied type signature or all its free variables are Global/ClosedLet or NonClosedLet with ClosedTypeId=True. In particular, none are NotLetBound. Why is (b) needed? Consider \x. (x :: Int, let y = x+1 in ...) Initially x::alpha. If we happen to typecheck the 'let' before the (x::Int), y's type will have a free tyvar; but if the other way round it won't. So we treat any let-bound variable with a free non-let-bound variable as not ClosedTypeId, regardless of what the free vars of its type actually are. But if it has a signature, all is well: \x. ...(let { y::Int; y = x+1 } in let { v = y+2 } in ...)... Here the signature on 'v' makes 'y' a ClosedTypeId, so we can generalise 'v'. Note that: * A top-level binding may not have ClosedTypeId=True, if it suffers from the MR * A nested binding may be closed (eg 'g' in the example we started with). Indeed, that's the point; whether a function is defined at top level or nested is orthogonal to the question of whether or not it is closed. * A binding may be non-closed because it mentions a lexically scoped *type variable* Eg f :: forall a. blah f x = let g y = ...(y::a)... Under OutsideIn we are free to generalise an Id all of whose free variables have ClosedTypeId=True (or imported). This is an extension compared to the JFP paper on OutsideIn, which used "top-level" as a proxy for "closed". (It's not a good proxy anyway -- the MR can make a top-level binding with a free type variable.) Note [Type variables in the type environment] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The type environment has a binding for each lexically-scoped type variable that is in scope. For example f :: forall a. a -> a f x = (x :: a) g1 :: [a] -> a g1 (ys :: [b]) = head ys :: b g2 :: [Int] -> Int g2 (ys :: [c]) = head ys :: c * The forall'd variable 'a' in the signature scopes over f's RHS. * The pattern-bound type variable 'b' in 'g1' scopes over g1's RHS; note that it is bound to a skolem 'a' which is not itself lexically in scope. * The pattern-bound type variable 'c' in 'g2' is bound to Int; that is, pattern-bound type variables can stand for arbitrary types. (see GHC proposal #128 "Allow ScopedTypeVariables to refer to types" https://github.com/ghc-proposals/ghc-proposals/pull/128, and the paper "Type variables in patterns", Haskell Symposium 2018. This is implemented by the constructor ATyVar Name TcTyVar in the type environment. * The Name is the name of the original, lexically scoped type variable * The TcTyVar is sometimes a skolem (like in 'f'), and sometimes a unification variable (like in 'g1', 'g2'). We never zonk the type environment so in the latter case it always stays as a unification variable, although that variable may be later unified with a type (such as Int in 'g2'). -} instance Outputable IdBindingInfo where ppr :: IdBindingInfo -> SDoc ppr IdBindingInfo NotLetBound = FilePath -> SDoc text FilePath "NotLetBound" ppr IdBindingInfo ClosedLet = FilePath -> SDoc text FilePath "TopLevelLet" ppr (NonClosedLet NameSet fvs Bool closed_type) = FilePath -> SDoc text FilePath "TopLevelLet" SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr NameSet fvs SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr Bool closed_type instance Outputable PromotionErr where ppr :: PromotionErr -> SDoc ppr PromotionErr ClassPE = FilePath -> SDoc text FilePath "ClassPE" ppr PromotionErr TyConPE = FilePath -> SDoc text FilePath "TyConPE" ppr PromotionErr PatSynPE = FilePath -> SDoc text FilePath "PatSynPE" ppr PromotionErr FamDataConPE = FilePath -> SDoc text FilePath "FamDataConPE" ppr (ConstrainedDataConPE Type pred) = FilePath -> SDoc text FilePath "ConstrainedDataConPE" SDoc -> SDoc -> SDoc <+> SDoc -> SDoc parens (forall a. Outputable a => a -> SDoc ppr Type pred) ppr PromotionErr RecDataConPE = FilePath -> SDoc text FilePath "RecDataConPE" ppr PromotionErr NoDataKindsTC = FilePath -> SDoc text FilePath "NoDataKindsTC" ppr PromotionErr NoDataKindsDC = FilePath -> SDoc text FilePath "NoDataKindsDC" -------------- pprTcTyThingCategory :: TcTyThing -> SDoc pprTcTyThingCategory :: TcTyThing -> SDoc pprTcTyThingCategory = FilePath -> SDoc text forall b c a. (b -> c) -> (a -> b) -> a -> c . FilePath -> FilePath capitalise forall b c a. (b -> c) -> (a -> b) -> a -> c . TcTyThing -> FilePath tcTyThingCategory tcTyThingCategory :: TcTyThing -> String tcTyThingCategory :: TcTyThing -> FilePath tcTyThingCategory (AGlobal TyThing thing) = TyThing -> FilePath tyThingCategory TyThing thing tcTyThingCategory (ATyVar {}) = FilePath "type variable" tcTyThingCategory (ATcId {}) = FilePath "local identifier" tcTyThingCategory (ATcTyCon {}) = FilePath "local tycon" tcTyThingCategory (APromotionErr PromotionErr pe) = PromotionErr -> FilePath peCategory PromotionErr pe -------------- pprPECategory :: PromotionErr -> SDoc pprPECategory :: PromotionErr -> SDoc pprPECategory = FilePath -> SDoc text forall b c a. (b -> c) -> (a -> b) -> a -> c . FilePath -> FilePath capitalise forall b c a. (b -> c) -> (a -> b) -> a -> c . PromotionErr -> FilePath peCategory peCategory :: PromotionErr -> String peCategory :: PromotionErr -> FilePath peCategory PromotionErr ClassPE = FilePath "class" peCategory PromotionErr TyConPE = FilePath "type constructor" peCategory PromotionErr PatSynPE = FilePath "pattern synonym" peCategory PromotionErr FamDataConPE = FilePath "data constructor" peCategory ConstrainedDataConPE{} = FilePath "data constructor" peCategory PromotionErr RecDataConPE = FilePath "data constructor" peCategory PromotionErr NoDataKindsTC = FilePath "type constructor" peCategory PromotionErr NoDataKindsDC = FilePath "data constructor" {- ************************************************************************ * * Operations over ImportAvails * * ************************************************************************ -} -- | 'ImportAvails' summarises what was imported from where, irrespective of -- whether the imported things are actually used or not. It is used: -- -- * when processing the export list, -- -- * when constructing usage info for the interface file, -- -- * to identify the list of directly imported modules for initialisation -- purposes and for optimised overlap checking of family instances, -- -- * when figuring out what things are really unused -- data ImportAvails = ImportAvails { ImportAvails -> ImportedMods imp_mods :: ImportedMods, -- = ModuleEnv [ImportedModsVal], -- ^ Domain is all directly-imported modules -- -- See the documentation on ImportedModsVal in -- "GHC.Unit.Module.Imported" for the meaning of the fields. -- -- We need a full ModuleEnv rather than a ModuleNameEnv here, -- because we might be importing modules of the same name from -- different packages. (currently not the case, but might be in the -- future). ImportAvails -> ModuleNameEnv ModuleNameWithIsBoot imp_dep_mods :: ModuleNameEnv ModuleNameWithIsBoot, -- ^ 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. ImportAvails -> Set UnitId imp_dep_pkgs :: Set UnitId, -- ^ Packages needed by the module being compiled, whether directly, -- or via other modules in this package, or via modules imported -- from other packages. ImportAvails -> Set UnitId imp_trust_pkgs :: Set UnitId, -- ^ This is strictly a subset of imp_dep_pkgs and records the -- packages the current module needs to trust for Safe Haskell -- compilation to succeed. A package is required to be trusted if -- we are dependent on a trustworthy module in that package. -- While perhaps making imp_dep_pkgs a tuple of (UnitId, Bool) -- where True for the bool indicates the package is required to be -- trusted is the more logical design, doing so complicates a lot -- of code not concerned with Safe Haskell. -- See Note [Tracking Trust Transitively] in "GHC.Rename.Names" ImportAvails -> Bool imp_trust_own_pkg :: Bool, -- ^ Do we require that our own package is trusted? -- This is to handle efficiently the case where a Safe module imports -- a Trustworthy module that resides in the same package as it. -- See Note [Trust Own Package] in "GHC.Rename.Names" ImportAvails -> [Module] imp_orphs :: [Module], -- ^ Orphan modules below us in the import tree (and maybe including -- us for imported modules) ImportAvails -> [Module] imp_finsts :: [Module] -- ^ Family instance modules below us in the import tree (and maybe -- including us for imported modules) } mkModDeps :: [ModuleNameWithIsBoot] -> ModuleNameEnv ModuleNameWithIsBoot mkModDeps :: [ModuleNameWithIsBoot] -> ModuleNameEnv ModuleNameWithIsBoot mkModDeps [ModuleNameWithIsBoot] deps = forall (t :: * -> *) b a. Foldable t => (b -> a -> b) -> b -> t a -> b foldl' forall {key}. Uniquable key => UniqFM key (GenWithIsBoot key) -> GenWithIsBoot key -> UniqFM key (GenWithIsBoot key) add forall key elt. UniqFM key elt emptyUFM [ModuleNameWithIsBoot] deps where add :: UniqFM key (GenWithIsBoot key) -> GenWithIsBoot key -> UniqFM key (GenWithIsBoot key) add UniqFM key (GenWithIsBoot key) env GenWithIsBoot key elt = forall key elt. Uniquable key => UniqFM key elt -> key -> elt -> UniqFM key elt addToUFM UniqFM key (GenWithIsBoot key) env (forall mod. GenWithIsBoot mod -> mod gwib_mod GenWithIsBoot key elt) GenWithIsBoot key elt modDepsElts :: ModuleNameEnv ModuleNameWithIsBoot -> [ModuleNameWithIsBoot] modDepsElts :: ModuleNameEnv ModuleNameWithIsBoot -> [ModuleNameWithIsBoot] modDepsElts = forall a. Ord a => [a] -> [a] sort forall b c a. (b -> c) -> (a -> b) -> a -> c . forall key elt. UniqFM key elt -> [elt] nonDetEltsUFM -- It's OK to use nonDetEltsUFM here because sorting by module names -- restores determinism emptyImportAvails :: ImportAvails emptyImportAvails :: ImportAvails emptyImportAvails = ImportAvails { imp_mods :: ImportedMods imp_mods = forall a. ModuleEnv a emptyModuleEnv, imp_dep_mods :: ModuleNameEnv ModuleNameWithIsBoot imp_dep_mods = forall key elt. UniqFM key elt emptyUFM, imp_dep_pkgs :: Set UnitId imp_dep_pkgs = forall a. Set a S.empty, imp_trust_pkgs :: Set UnitId imp_trust_pkgs = forall a. Set a S.empty, imp_trust_own_pkg :: Bool imp_trust_own_pkg = Bool False, imp_orphs :: [Module] imp_orphs = [], imp_finsts :: [Module] imp_finsts = [] } -- | Union two ImportAvails -- -- This function is a key part of Import handling, basically -- for each import we create a separate ImportAvails structure -- and then union them all together with this function. plusImportAvails :: ImportAvails -> ImportAvails -> ImportAvails plusImportAvails :: ImportAvails -> ImportAvails -> ImportAvails plusImportAvails (ImportAvails { imp_mods :: ImportAvails -> ImportedMods imp_mods = ImportedMods mods1, imp_dep_mods :: ImportAvails -> ModuleNameEnv ModuleNameWithIsBoot imp_dep_mods = ModuleNameEnv ModuleNameWithIsBoot dmods1, imp_dep_pkgs :: ImportAvails -> Set UnitId imp_dep_pkgs = Set UnitId dpkgs1, imp_trust_pkgs :: ImportAvails -> Set UnitId imp_trust_pkgs = Set UnitId tpkgs1, imp_trust_own_pkg :: ImportAvails -> Bool imp_trust_own_pkg = Bool tself1, imp_orphs :: ImportAvails -> [Module] imp_orphs = [Module] orphs1, imp_finsts :: ImportAvails -> [Module] imp_finsts = [Module] finsts1 }) (ImportAvails { imp_mods :: ImportAvails -> ImportedMods imp_mods = ImportedMods mods2, imp_dep_mods :: ImportAvails -> ModuleNameEnv ModuleNameWithIsBoot imp_dep_mods = ModuleNameEnv ModuleNameWithIsBoot dmods2, imp_dep_pkgs :: ImportAvails -> Set UnitId imp_dep_pkgs = Set UnitId dpkgs2, imp_trust_pkgs :: ImportAvails -> Set UnitId imp_trust_pkgs = Set UnitId tpkgs2, imp_trust_own_pkg :: ImportAvails -> Bool imp_trust_own_pkg = Bool tself2, imp_orphs :: ImportAvails -> [Module] imp_orphs = [Module] orphs2, imp_finsts :: ImportAvails -> [Module] imp_finsts = [Module] finsts2 }) = ImportAvails { imp_mods :: ImportedMods imp_mods = forall a. (a -> a -> a) -> ModuleEnv a -> ModuleEnv a -> ModuleEnv a plusModuleEnv_C forall a. [a] -> [a] -> [a] (++) ImportedMods mods1 ImportedMods mods2, imp_dep_mods :: ModuleNameEnv ModuleNameWithIsBoot imp_dep_mods = forall elt key. (elt -> elt -> elt) -> UniqFM key elt -> UniqFM key elt -> UniqFM key elt plusUFM_C forall {a}. (Eq a, Outputable a) => GenWithIsBoot a -> GenWithIsBoot a -> GenWithIsBoot a plus_mod_dep ModuleNameEnv ModuleNameWithIsBoot dmods1 ModuleNameEnv ModuleNameWithIsBoot dmods2, imp_dep_pkgs :: Set UnitId imp_dep_pkgs = Set UnitId dpkgs1 forall a. Ord a => Set a -> Set a -> Set a `S.union` Set UnitId dpkgs2, imp_trust_pkgs :: Set UnitId imp_trust_pkgs = Set UnitId tpkgs1 forall a. Ord a => Set a -> Set a -> Set a `S.union` Set UnitId tpkgs2, imp_trust_own_pkg :: Bool imp_trust_own_pkg = Bool tself1 Bool -> Bool -> Bool || Bool tself2, imp_orphs :: [Module] imp_orphs = [Module] orphs1 forall a. (HasDebugCallStack, Outputable a, Eq a) => [a] -> [a] -> [a] `unionLists` [Module] orphs2, imp_finsts :: [Module] imp_finsts = [Module] finsts1 forall a. (HasDebugCallStack, Outputable a, Eq a) => [a] -> [a] -> [a] `unionLists` [Module] finsts2 } where plus_mod_dep :: GenWithIsBoot a -> GenWithIsBoot a -> GenWithIsBoot a plus_mod_dep r1 :: GenWithIsBoot a r1@(GWIB { gwib_mod :: forall mod. GenWithIsBoot mod -> mod gwib_mod = a m1, gwib_isBoot :: forall mod. GenWithIsBoot mod -> IsBootInterface gwib_isBoot = IsBootInterface boot1 }) r2 :: GenWithIsBoot a r2@(GWIB {gwib_mod :: forall mod. GenWithIsBoot mod -> mod gwib_mod = a m2, gwib_isBoot :: forall mod. GenWithIsBoot mod -> IsBootInterface gwib_isBoot = IsBootInterface boot2}) | ASSERT2( m1 == m2, (ppr m1 <+> ppr m2) $$ (ppr (boot1 == IsBoot) <+> ppr (boot2 == IsBoot))) IsBootInterface boot1 forall a. Eq a => a -> a -> Bool == IsBootInterface IsBoot = GenWithIsBoot a r2 | Bool otherwise = GenWithIsBoot a r1 -- If either side can "see" a non-hi-boot interface, use that -- Reusing existing tuples saves 10% of allocations on test -- perf/compiler/MultiLayerModules {- ************************************************************************ * * \subsection{Where from} * * ************************************************************************ The @WhereFrom@ type controls where the renamer looks for an interface file -} data WhereFrom = ImportByUser IsBootInterface -- Ordinary user import (perhaps {-# SOURCE #-}) | ImportBySystem -- Non user import. | ImportByPlugin -- Importing a plugin; -- See Note [Care with plugin imports] in GHC.Iface.Load instance Outputable WhereFrom where ppr :: WhereFrom -> SDoc ppr (ImportByUser IsBootInterface IsBoot) = FilePath -> SDoc text FilePath "{- SOURCE -}" ppr (ImportByUser IsBootInterface NotBoot) = SDoc empty ppr WhereFrom ImportBySystem = FilePath -> SDoc text FilePath "{- SYSTEM -}" ppr WhereFrom ImportByPlugin = FilePath -> SDoc text FilePath "{- PLUGIN -}" {- ********************************************************************* * * Type signatures * * ********************************************************************* -} -- These data types need to be here only because -- GHC.Tc.Solver uses them, and GHC.Tc.Solver is fairly -- low down in the module hierarchy type TcSigFun = Name -> Maybe TcSigInfo data TcSigInfo = TcIdSig TcIdSigInfo | TcPatSynSig TcPatSynInfo data TcIdSigInfo -- See Note [Complete and partial type signatures] = CompleteSig -- A complete signature with no wildcards, -- so the complete polymorphic type is known. { TcIdSigInfo -> TyVar sig_bndr :: TcId -- The polymorphic Id with that type , TcIdSigInfo -> UserTypeCtxt sig_ctxt :: UserTypeCtxt -- In the case of type-class default methods, -- the Name in the FunSigCtxt is not the same -- as the TcId; the former is 'op', while the -- latter is '$dmop' or some such , TcIdSigInfo -> SrcSpan sig_loc :: SrcSpan -- Location of the type signature } | PartialSig -- A partial type signature (i.e. includes one or more -- wildcards). In this case it doesn't make sense to give -- the polymorphic Id, because we are going to /infer/ its -- type, so we can't make the polymorphic Id ab-initio { TcIdSigInfo -> Name psig_name :: Name -- Name of the function; used when report wildcards , TcIdSigInfo -> LHsSigWcType GhcRn psig_hs_ty :: LHsSigWcType GhcRn -- The original partial signature in -- HsSyn form , sig_ctxt :: UserTypeCtxt , sig_loc :: SrcSpan -- Location of the type signature } {- Note [Complete and partial type signatures] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A type signature is partial when it contains one or more wildcards (= type holes). The wildcard can either be: * A (type) wildcard occurring in sig_theta or sig_tau. These are stored in sig_wcs. f :: Bool -> _ g :: Eq _a => _a -> _a -> Bool * Or an extra-constraints wildcard, stored in sig_cts: h :: (Num a, _) => a -> a A type signature is a complete type signature when there are no wildcards in the type signature, i.e. iff sig_wcs is empty and sig_extra_cts is Nothing. -} data TcIdSigInst = TISI { TcIdSigInst -> TcIdSigInfo sig_inst_sig :: TcIdSigInfo , TcIdSigInst -> [(Name, InvisTVBinder)] sig_inst_skols :: [(Name, InvisTVBinder)] -- Instantiated type and kind variables, TyVarTvs -- The Name is the Name that the renamer chose; -- but the TcTyVar may come from instantiating -- the type and hence have a different unique. -- No need to keep track of whether they are truly lexically -- scoped because the renamer has named them uniquely -- See Note [Binding scoped type variables] in GHC.Tc.Gen.Sig -- -- NB: The order of sig_inst_skols is irrelevant -- for a CompleteSig, but for a PartialSig see -- Note [Quantified variables in partial type signatures] , TcIdSigInst -> [Type] sig_inst_theta :: TcThetaType -- Instantiated theta. In the case of a -- PartialSig, sig_theta does not include -- the extra-constraints wildcard , TcIdSigInst -> Type sig_inst_tau :: TcSigmaType -- Instantiated tau -- See Note [sig_inst_tau may be polymorphic] -- Relevant for partial signature only , TcIdSigInst -> [(Name, TyVar)] sig_inst_wcs :: [(Name, TcTyVar)] -- Like sig_inst_skols, but for /named/ wildcards (_a etc). -- The named wildcards scope over the binding, and hence -- their Names may appear in type signatures in the binding , TcIdSigInst -> Maybe Type sig_inst_wcx :: Maybe TcType -- Extra-constraints wildcard to fill in, if any -- If this exists, it is surely of the form (meta_tv |> co) -- (where the co might be reflexive). This is filled in -- only from the return value of GHC.Tc.Gen.HsType.tcAnonWildCardOcc } {- Note [sig_inst_tau may be polymorphic] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Note that "sig_inst_tau" might actually be a polymorphic type, if the original function had a signature like forall a. Eq a => forall b. Ord b => .... But that's ok: tcMatchesFun (called by tcRhs) can deal with that It happens, too! See Note [Polymorphic methods] in GHC.Tc.TyCl.Class. Note [Quantified variables in partial type signatures] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Consider f :: forall a b. _ -> a -> _ -> b f (x,y) p q = q Then we expect f's final type to be f :: forall {x,y}. forall a b. (x,y) -> a -> b -> b Note that x,y are Inferred, and can't be use for visible type application (VTA). But a,b are Specified, and remain Specified in the final type, so we can use VTA for them. (Exception: if it turns out that a's kind mentions b we need to reorder them with scopedSort.) The sig_inst_skols of the TISI from a partial signature records that original order, and is used to get the variables of f's final type in the correct order. Note [Wildcards in partial signatures] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The wildcards in psig_wcs may stand for a type mentioning the universally-quantified tyvars of psig_ty E.g. f :: forall a. _ -> a f x = x We get sig_inst_skols = [a] sig_inst_tau = _22 -> a sig_inst_wcs = [_22] and _22 in the end is unified with the type 'a' Moreover the kind of a wildcard in sig_inst_wcs may mention the universally-quantified tyvars sig_inst_skols e.g. f :: t a -> t _ Here we get sig_inst_skols = [k:*, (t::k ->*), (a::k)] sig_inst_tau = t a -> t _22 sig_inst_wcs = [ _22::k ] -} data TcPatSynInfo = TPSI { TcPatSynInfo -> Name patsig_name :: Name, TcPatSynInfo -> [InvisTVBinder] patsig_implicit_bndrs :: [InvisTVBinder], -- Implicitly-bound kind vars (Inferred) and -- implicitly-bound type vars (Specified) -- See Note [The pattern-synonym signature splitting rule] in GHC.Tc.TyCl.PatSyn TcPatSynInfo -> [InvisTVBinder] patsig_univ_bndrs :: [InvisTVBinder], -- Bound by explicit user forall TcPatSynInfo -> [Type] patsig_req :: TcThetaType, TcPatSynInfo -> [InvisTVBinder] patsig_ex_bndrs :: [InvisTVBinder], -- Bound by explicit user forall TcPatSynInfo -> [Type] patsig_prov :: TcThetaType, TcPatSynInfo -> Type patsig_body_ty :: TcSigmaType } instance Outputable TcSigInfo where ppr :: TcSigInfo -> SDoc ppr (TcIdSig TcIdSigInfo idsi) = forall a. Outputable a => a -> SDoc ppr TcIdSigInfo idsi ppr (TcPatSynSig TcPatSynInfo tpsi) = FilePath -> SDoc text FilePath "TcPatSynInfo" SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr TcPatSynInfo tpsi instance Outputable TcIdSigInfo where ppr :: TcIdSigInfo -> SDoc ppr (CompleteSig { sig_bndr :: TcIdSigInfo -> TyVar sig_bndr = TyVar bndr }) = forall a. Outputable a => a -> SDoc ppr TyVar bndr SDoc -> SDoc -> SDoc <+> SDoc dcolon SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr (TyVar -> Type idType TyVar bndr) ppr (PartialSig { psig_name :: TcIdSigInfo -> Name psig_name = Name name, psig_hs_ty :: TcIdSigInfo -> LHsSigWcType GhcRn psig_hs_ty = LHsSigWcType GhcRn hs_ty }) = FilePath -> SDoc text FilePath "psig" SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr Name name SDoc -> SDoc -> SDoc <+> SDoc dcolon SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr LHsSigWcType GhcRn hs_ty instance Outputable TcIdSigInst where ppr :: TcIdSigInst -> SDoc ppr (TISI { sig_inst_sig :: TcIdSigInst -> TcIdSigInfo sig_inst_sig = TcIdSigInfo sig, sig_inst_skols :: TcIdSigInst -> [(Name, InvisTVBinder)] sig_inst_skols = [(Name, InvisTVBinder)] skols , sig_inst_theta :: TcIdSigInst -> [Type] sig_inst_theta = [Type] theta, sig_inst_tau :: TcIdSigInst -> Type sig_inst_tau = Type tau }) = SDoc -> ThLevel -> SDoc -> SDoc hang (forall a. Outputable a => a -> SDoc ppr TcIdSigInfo sig) ThLevel 2 ([SDoc] -> SDoc vcat [ forall a. Outputable a => a -> SDoc ppr [(Name, InvisTVBinder)] skols, forall a. Outputable a => a -> SDoc ppr [Type] theta SDoc -> SDoc -> SDoc <+> SDoc darrow SDoc -> SDoc -> SDoc <+> forall a. Outputable a => a -> SDoc ppr Type tau ]) instance Outputable TcPatSynInfo where ppr :: TcPatSynInfo -> SDoc ppr (TPSI{ patsig_name :: TcPatSynInfo -> Name patsig_name = Name name}) = forall a. Outputable a => a -> SDoc ppr Name name isPartialSig :: TcIdSigInst -> Bool isPartialSig :: TcIdSigInst -> Bool isPartialSig (TISI { sig_inst_sig :: TcIdSigInst -> TcIdSigInfo sig_inst_sig = PartialSig {} }) = Bool True isPartialSig TcIdSigInst _ = Bool False -- | No signature or a partial signature hasCompleteSig :: TcSigFun -> Name -> Bool hasCompleteSig :: TcSigFun -> Name -> Bool hasCompleteSig TcSigFun sig_fn Name name = case TcSigFun sig_fn Name name of Just (TcIdSig (CompleteSig {})) -> Bool True Maybe TcSigInfo _ -> Bool False {- Constraint Solver Plugins ------------------------- -} type TcPluginSolver = [Ct] -- given -> [Ct] -- derived -> [Ct] -- wanted -> TcPluginM TcPluginResult newtype TcPluginM a = TcPluginM (EvBindsVar -> TcM a) deriving (forall a b. a -> TcPluginM b -> TcPluginM a forall a b. (a -> b) -> TcPluginM a -> TcPluginM b forall (f :: * -> *). (forall a b. (a -> b) -> f a -> f b) -> (forall a b. a -> f b -> f a) -> Functor f <$ :: forall a b. a -> TcPluginM b -> TcPluginM a $c<$ :: forall a b. a -> TcPluginM b -> TcPluginM a fmap :: forall a b. (a -> b) -> TcPluginM a -> TcPluginM b $cfmap :: forall a b. (a -> b) -> TcPluginM a -> TcPluginM b Functor) instance Applicative TcPluginM where pure :: forall a. a -> TcPluginM a pure a x = forall a. (EvBindsVar -> TcM a) -> TcPluginM a TcPluginM (forall a b. a -> b -> a const forall a b. (a -> b) -> a -> b $ forall (f :: * -> *) a. Applicative f => a -> f a pure a x) <*> :: forall a b. TcPluginM (a -> b) -> TcPluginM a -> TcPluginM b (<*>) = forall (m :: * -> *) a b. Monad m => m (a -> b) -> m a -> m b ap instance Monad TcPluginM where TcPluginM EvBindsVar -> TcM a m >>= :: forall a b. TcPluginM a -> (a -> TcPluginM b) -> TcPluginM b >>= a -> TcPluginM b k = forall a. (EvBindsVar -> TcM a) -> TcPluginM a TcPluginM (\ EvBindsVar ev -> do a a <- EvBindsVar -> TcM a m EvBindsVar ev forall a. TcPluginM a -> EvBindsVar -> TcM a runTcPluginM (a -> TcPluginM b k a a) EvBindsVar ev) instance MonadFail TcPluginM where fail :: forall a. FilePath -> TcPluginM a fail FilePath x = forall a. (EvBindsVar -> TcM a) -> TcPluginM a TcPluginM (forall a b. a -> b -> a const forall a b. (a -> b) -> a -> b $ forall (m :: * -> *) a. MonadFail m => FilePath -> m a fail FilePath x) runTcPluginM :: TcPluginM a -> EvBindsVar -> TcM a runTcPluginM :: forall a. TcPluginM a -> EvBindsVar -> TcM a runTcPluginM (TcPluginM EvBindsVar -> TcM a m) = EvBindsVar -> TcM a m -- | This function provides an escape for direct access to -- the 'TcM` monad. It should not be used lightly, and -- the provided 'TcPluginM' API should be favoured instead. unsafeTcPluginTcM :: TcM a -> TcPluginM a unsafeTcPluginTcM :: forall a. TcM a -> TcPluginM a unsafeTcPluginTcM = forall a. (EvBindsVar -> TcM a) -> TcPluginM a TcPluginM forall b c a. (b -> c) -> (a -> b) -> a -> c . forall a b. a -> b -> a const -- | Access the 'EvBindsVar' carried by the 'TcPluginM' during -- constraint solving. Returns 'Nothing' if invoked during -- 'tcPluginInit' or 'tcPluginStop'. getEvBindsTcPluginM :: TcPluginM EvBindsVar getEvBindsTcPluginM :: TcPluginM EvBindsVar getEvBindsTcPluginM = forall a. (EvBindsVar -> TcM a) -> TcPluginM a TcPluginM forall (m :: * -> *) a. Monad m => a -> m a return data TcPlugin = forall s. TcPlugin { () tcPluginInit :: TcPluginM s -- ^ Initialize plugin, when entering type-checker. , () tcPluginSolve :: s -> TcPluginSolver -- ^ Solve some constraints. -- TODO: WRITE MORE DETAILS ON HOW THIS WORKS. , () tcPluginStop :: s -> TcPluginM () -- ^ Clean up after the plugin, when exiting the type-checker. } data TcPluginResult = TcPluginContradiction [Ct] -- ^ The plugin found a contradiction. -- The returned constraints are removed from the inert set, -- and recorded as insoluble. | TcPluginOk [(EvTerm,Ct)] [Ct] -- ^ The first field is for constraints that were solved. -- These are removed from the inert set, -- and the evidence for them is recorded. -- The second field contains new work, that should be processed by -- the constraint solver. {- ********************************************************************* * * Role annotations * * ********************************************************************* -} type RoleAnnotEnv = NameEnv (LRoleAnnotDecl GhcRn) mkRoleAnnotEnv :: [LRoleAnnotDecl GhcRn] -> RoleAnnotEnv mkRoleAnnotEnv :: [LRoleAnnotDecl GhcRn] -> RoleAnnotEnv mkRoleAnnotEnv [LRoleAnnotDecl GhcRn] role_annot_decls = forall a. [(Name, a)] -> NameEnv a mkNameEnv [ (IdP GhcRn name, GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn) ra_decl) | GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn) ra_decl <- [LRoleAnnotDecl GhcRn] role_annot_decls , let name :: IdP GhcRn name = forall (p :: Pass). RoleAnnotDecl (GhcPass p) -> IdP (GhcPass p) roleAnnotDeclName (forall l e. GenLocated l e -> e unLoc GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn) ra_decl) , Bool -> Bool not (Name -> Bool isUnboundName IdP GhcRn name) ] -- Some of the role annots will be unbound; -- we don't wish to include these emptyRoleAnnotEnv :: RoleAnnotEnv emptyRoleAnnotEnv :: RoleAnnotEnv emptyRoleAnnotEnv = forall a. NameEnv a emptyNameEnv lookupRoleAnnot :: RoleAnnotEnv -> Name -> Maybe (LRoleAnnotDecl GhcRn) lookupRoleAnnot :: RoleAnnotEnv -> Name -> Maybe (LRoleAnnotDecl GhcRn) lookupRoleAnnot = forall a. NameEnv a -> Name -> Maybe a lookupNameEnv getRoleAnnots :: [Name] -> RoleAnnotEnv -> [LRoleAnnotDecl GhcRn] getRoleAnnots :: [Name] -> RoleAnnotEnv -> [LRoleAnnotDecl GhcRn] getRoleAnnots [Name] bndrs RoleAnnotEnv role_env = forall a b. (a -> Maybe b) -> [a] -> [b] mapMaybe (RoleAnnotEnv -> Name -> Maybe (LRoleAnnotDecl GhcRn) lookupRoleAnnot RoleAnnotEnv role_env) [Name] bndrs {- ********************************************************************* * * Linting a TcGblEnv * * ********************************************************************* -} -- | Check the 'TcGblEnv' for consistency. Currently, only checks -- axioms, but should check other aspects, too. lintGblEnv :: Logger -> DynFlags -> TcGblEnv -> TcM () lintGblEnv :: Logger -> DynFlags -> TcGblEnv -> TcM () lintGblEnv Logger logger DynFlags dflags TcGblEnv tcg_env = forall (m :: * -> *) a. MonadIO m => IO a -> m a liftIO forall a b. (a -> b) -> a -> b $ Logger -> DynFlags -> SDoc -> [CoAxiom Branched] -> IO () lintAxioms Logger logger DynFlags dflags (FilePath -> SDoc text FilePath "TcGblEnv axioms") [CoAxiom Branched] axioms where axioms :: [CoAxiom Branched] axioms = TypeEnv -> [CoAxiom Branched] typeEnvCoAxioms (TcGblEnv -> TypeEnv tcg_type_env TcGblEnv tcg_env) -- | This is a mirror of Template Haskell's DocLoc, but the TH names are -- resolved to GHC names. data DocLoc = DeclDoc Name | ArgDoc Name Int | InstDoc Name | ModuleDoc deriving (DocLoc -> DocLoc -> Bool forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a /= :: DocLoc -> DocLoc -> Bool $c/= :: DocLoc -> DocLoc -> Bool == :: DocLoc -> DocLoc -> Bool $c== :: DocLoc -> DocLoc -> Bool Eq, Eq DocLoc DocLoc -> DocLoc -> Bool DocLoc -> DocLoc -> Ordering DocLoc -> DocLoc -> DocLoc forall a. Eq a -> (a -> a -> Ordering) -> (a -> a -> Bool) -> (a -> a -> Bool) -> (a -> a -> Bool) -> (a -> a -> Bool) -> (a -> a -> a) -> (a -> a -> a) -> Ord a min :: DocLoc -> DocLoc -> DocLoc $cmin :: DocLoc -> DocLoc -> DocLoc max :: DocLoc -> DocLoc -> DocLoc $cmax :: DocLoc -> DocLoc -> DocLoc >= :: DocLoc -> DocLoc -> Bool $c>= :: DocLoc -> DocLoc -> Bool > :: DocLoc -> DocLoc -> Bool $c> :: DocLoc -> DocLoc -> Bool <= :: DocLoc -> DocLoc -> Bool $c<= :: DocLoc -> DocLoc -> Bool < :: DocLoc -> DocLoc -> Bool $c< :: DocLoc -> DocLoc -> Bool compare :: DocLoc -> DocLoc -> Ordering $ccompare :: DocLoc -> DocLoc -> Ordering Ord) -- | The current collection of docs that Template Haskell has built up via -- putDoc. type THDocs = Map DocLoc String