Documentation

Fields

• env_top :: !HscEnv
   
• env_us :: !(IORef UniqSupply)
   
• env_gbl :: gbl
   
• env_lcl :: lcl
   

Fields

• tcg_mod :: Module

  Module being compiled

• tcg_semantic_mod :: Module

  If a signature, the backing module See also Note [Identity versus semantic module]

• tcg_src :: HscSource

  What kind of module (regular Haskell, hs-boot, hsig)

• tcg_rdr_env :: GlobalRdrEnv

  Top level envt; used during renaming

• tcg_default :: Maybe [Type]

  Types used for defaulting. Nothing => no default decl

• tcg_fix_env :: FixityEnv

  Just for things in this module

• tcg_field_env :: RecFieldEnv

  Just for things in this module See Note [The interactive package] in HscTypes

• 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 HscTypes

• tcg_type_env_var :: TcRef TypeEnv
   
• 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

• tcg_fam_inst_env :: !FamInstEnv

  Ditto for family instances NB. BangPattern is to fix a leak, see #15111

• tcg_ann_env :: AnnEnv

  And for annotations

• tcg_exports :: [AvailInfo]

  What is exported

• 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 HscMain) - To create the Dependencies field in interface (mkDependencies)

• tcg_dus :: DefUses

  What is defined in this module and what is used.

• tcg_used_gres :: TcRef [GlobalRdrElt]

  Records occurrences of imported entities See Note [Tracking unused binding and imports]

• 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_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.

• tcg_th_splice_used :: TcRef Bool

  True = A Template Haskell splice was used.

  Splices disable recompilation avoidance (see #481)

• tcg_th_top_level_locs :: TcRef (Set RealSrcSpan)

  Locations of the top-level splices; used for providing details on scope in error messages for out-of-scope variables

• tcg_dfun_n :: TcRef OccSet

  Allows us to choose unique DFun names.

• tcg_merged :: [(Module, Fingerprint)]

  The requirements we merged with; we always have to recompile if any of these changed.

• tcg_rn_exports :: Maybe [(Located (IE GhcRn), Avails)]
   
• tcg_rn_imports :: [LImportDecl GhcRn]
   
• tcg_rn_decls :: Maybe (HsGroup GhcRn)

  Renamed decls, maybe. Nothing = Don't retain renamed decls.

• tcg_dependent_files :: TcRef [FilePath]

  dependencies from addDependentFile

• tcg_th_topdecls :: TcRef [LHsDecl GhcPs]

  Top-level declarations from addTopDecls

• tcg_th_foreign_files :: TcRef [(ForeignSrcLang, FilePath)]

  Foreign files emitted from TH.

• tcg_th_topnames :: TcRef NameSet

  Exact names bound in top-level declarations in tcg_th_topdecls

• tcg_th_modfinalizers :: TcRef [TcM ()]

  Template Haskell module finalizers.

  They are computations in the TcM monad rather than Q because we set them to use particular local environments.

• tcg_th_coreplugins :: TcRef [String]

  Core plugins added by Template Haskell code.

• tcg_th_state :: TcRef (Map TypeRep Dynamic)
   
• tcg_th_remote_state :: TcRef (Maybe (ForeignRef (IORef QState)))

  Template Haskell state

• tcg_ev_binds :: Bag EvBind
   
• tcg_tr_module :: Maybe Id
   
• tcg_binds :: LHsBinds GhcTc
   
• tcg_sigs :: NameSet
   
• tcg_imp_specs :: [LTcSpecPrag]
   
• tcg_warns :: Warnings
   
• tcg_anns :: [Annotation]
   
• tcg_tcs :: [TyCon]
   
• tcg_insts :: [ClsInst]
   
• tcg_fam_insts :: [FamInst]
   
• tcg_rules :: [LRuleDecl GhcTc]
   
• tcg_fords :: [LForeignDecl GhcTc]
   
• tcg_patsyns :: [PatSyn]
   
• tcg_doc_hdr :: Maybe LHsDocString

  Maybe Haddock header docs

• tcg_hpc :: !AnyHpcUsage

  True if any part of the prog uses hpc instrumentation. NB. BangPattern is to fix a leak, see #15111

• tcg_self_boot :: SelfBootInfo

  Whether this module has a corresponding hi-boot file

• tcg_main :: Maybe Name

  The Name of the main function, if this module is the main module.

• 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.

• tcg_tc_plugins :: [TcPluginSolver]

  A list of user-defined plugins for the constraint solver.

• tcg_top_loc :: RealSrcSpan

  The RealSrcSpan this module came from

• tcg_static_wc :: TcRef WantedConstraints

  Wanted constraints of static forms. See Note [Constraints in static forms].

• tcg_complete_matches :: [CompleteMatch]

  Tracking indices for cost centre annotations

• tcg_cc_st :: TcRef CostCentreState
   

Fields

• tcl_loc :: RealSrcSpan
   
• tcl_ctxt :: [ErrCtxt]
   
• tcl_tclvl :: TcLevel
   
• tcl_th_ctxt :: ThStage
   
• tcl_th_bndrs :: ThBindEnv
   
• tcl_arrow_ctxt :: ArrowCtxt
   
• tcl_rdr :: LocalRdrEnv
   
• tcl_env :: TcTypeEnv
   
• tcl_bndrs :: TcBinderStack
   
• tcl_tyvars :: TcRef TcTyVarSet
   
• tcl_lie :: TcRef WantedConstraints
   
• tcl_errs :: TcRef Messages
   

Fields

• if_doc :: SDoc
   
• if_rec_types :: Maybe (Module, IfG TypeEnv)
   

Fields

• if_mod :: Module
   
• if_boot :: Bool
   
• if_loc :: SDoc
   
• if_nsubst :: Maybe NameShape
   
• if_implicits_env :: Maybe TypeEnv
   
• if_tv_env :: FastStringEnv TyVar
   
• if_id_env :: FastStringEnv Id
   

Fields

• imp_mods :: ImportedMods

  Domain is all directly-imported modules

  See the documentation on ImportedModsVal in HscTypes 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).

• imp_dep_mods :: ModuleNameEnv (ModuleName, 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 :: Set InstalledUnitId

  Packages needed by the module being compiled, whether directly, or via other modules in this package, or via modules imported from other packages.

• imp_trust_pkgs :: Set InstalledUnitId

  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 [RnNames . Tracking Trust Transitively]

• 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 [RnNames . Trust Own Package]

• imp_orphs :: [Module]

  Orphan modules below us in the import tree (and maybe including us for imported modules)

• imp_finsts :: [Module]

  Family instance modules below us in the import tree (and maybe including us for imported modules)

Fields

• tct_id :: TcId
   
• tct_info :: IdBindingInfo
   

Fields

• sb_mds :: ModDetails
   
• sb_tcs :: NameSet
   

Fields

• completeMatchConLikes :: [Name]

  The ConLikes that form a covering family (e.g. Nothing, Just)

• completeMatchTyCon :: Name

  The TyCon that they cover (e.g. Maybe)

Fields

• dsl_meta :: DsMetaEnv
   
• dsl_loc :: RealSrcSpan
   
• dsl_dicts :: Bag EvVar
   
• dsl_tm_cs :: Bag SimpleEq
   
• dsl_pm_iter :: IORef Int
   

Fields

• ds_mod :: Module
   
• ds_fam_inst_env :: FamInstEnv
   
• ds_unqual :: PrintUnqualified
   
• ds_msgs :: IORef Messages
   
• ds_if_env :: (IfGblEnv, IfLclEnv)
   
• ds_complete_matches :: CompleteMatchMap
   
• ds_cc_st :: IORef CostCentreState
   

Fields

• sig_bndr :: TcId
   
• sig_ctxt :: UserTypeCtxt
   
• sig_loc :: SrcSpan
   

Fields

• psig_name :: Name
   
• psig_hs_ty :: LHsSigWcType GhcRn
   
• sig_ctxt :: UserTypeCtxt
   
• sig_loc :: SrcSpan
   

Fields

• sig_inst_sig :: TcIdSigInfo
   
• sig_inst_skols :: [(Name, TcTyVar)]
   
• sig_inst_theta :: TcThetaType
   
• sig_inst_tau :: TcSigmaType
   
• sig_inst_wcs :: [(Name, TcTyVar)]
   
• sig_inst_wcx :: Maybe TcType
   

Fields

• patsig_name :: Name
   
• patsig_implicit_bndrs :: [TyVarBinder]
   
• patsig_univ_bndrs :: [TyVar]
   
• patsig_req :: TcThetaType
   
• patsig_ex_bndrs :: [TyVar]
   
• patsig_prov :: TcThetaType
   
• patsig_body_ty :: TcSigmaType
   

Fields

• qci_ev :: CtEvidence
   
• qci_tvs :: [TcTyVar]
   
• qci_pred :: TcPredType
   
• qci_pend_sc :: Bool
   

Fields

• cc_ev :: CtEvidence
   
• cc_class :: Class
   
• cc_tyargs :: [Xi]
   
• cc_pend_sc :: Bool
   

Fields

• cc_ev :: CtEvidence
   
• cc_insol :: Bool
   

Fields

• cc_ev :: CtEvidence
   
• cc_tyvar :: TcTyVar
   
• cc_rhs :: TcType
   
• cc_eq_rel :: EqRel
   

Fields

• cc_ev :: CtEvidence
   
• cc_fun :: TyCon
   
• cc_tyargs :: [Xi]
   
• cc_fsk :: TcTyVar
   

Fields

• cc_ev :: CtEvidence
   

Fields

• cc_ev :: CtEvidence
   
• cc_hole :: Hole
   

Fields

• wc_simple :: Cts
   
• wc_impl :: Bag Implication
   

Fields

• ic_tclvl :: TcLevel
   
• ic_skols :: [TcTyVar]
   
• ic_info :: SkolemInfo
   
• ic_telescope :: Maybe SDoc
   
• ic_given :: [EvVar]
   
• ic_no_eqs :: Bool
   
• ic_env :: Env TcGblEnv TcLclEnv
   
• ic_wanted :: WantedConstraints
   
• ic_binds :: EvBindsVar
   
• ic_need_inner :: VarSet
   
• ic_need_outer :: VarSet
   
• ic_status :: ImplicStatus
   

Fields

• ics_dead :: [EvVar]
   

Fields

• ctl_origin :: CtOrigin
   
• ctl_env :: TcLclEnv
   
• ctl_t_or_k :: Maybe TypeOrKind
   
• ctl_depth :: !SubGoalDepth
   

Fields

• uo_actual :: TcType
   
• uo_expected :: TcType
   
• uo_thing :: Maybe SDoc

  The thing that has type "actual"

• uo_visible :: Bool

  Is at least one of the three elements above visible? (Errors from the polymorphic subsumption check are considered visible.) Only used for prioritizing error messages.

Fields

• ctev_pred :: TcPredType
   
• ctev_evar :: EvVar
   
• ctev_loc :: CtLoc
   

Fields

• ctev_pred :: TcPredType
   
• ctev_dest :: TcEvDest
   
• ctev_nosh :: ShadowInfo
   
• ctev_loc :: CtLoc
   

Fields

• ctev_pred :: TcPredType
   
• ctev_loc :: CtLoc
   

Fields

• 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.