Documentation

Fields

• env_top :: !HscEnv
   
• env_um :: !Char
   
• 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 GHC.Runtime.Context

• 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

• tcg_type_env_var :: KnotVars (IORef 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 GHC.Driver.Main) - To create the Dependencies field in interface (mkDependencies)

• tcg_dus :: DefUses
   
• tcg_used_gres :: TcRef [GlobalRdrElt]
   
• tcg_keep :: TcRef NameSet
   
• 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_needed_deps :: TcRef ([Linkable], PkgsLoaded)

  The set of runtime dependencies required by this module See Note [Object File Dependencies]

• 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 [(LIE 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 [(TcLclEnv, ThModFinalizers)]

  Template Haskell module finalizers.

  They can 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_th_docs :: TcRef THDocs

  Docs added in Template Haskell via putDoc.

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

  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_safe_infer :: TcRef Bool

  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_safe_infer_reasons :: TcRef (Messages TcRnMessage)

  Unreported reasons why tcg_safe_infer is False. INVARIANT: If this Messages is non-empty, then tcg_safe_infer is False. It may be that tcg_safe_infer is False but this is empty, if no reasons are supplied (#19714), or if those reasons have already been reported by GHC.Driver.Main.markUnsafeInfer

• tcg_tc_plugin_solvers :: [TcPluginSolver]

  A list of user-defined type-checking plugins for constraint solving.

• tcg_tc_plugin_rewriters :: UniqFM TyCon [TcPluginRewriter]

  A collection of all the user-defined type-checking plugins for rewriting type family applications, collated by their type family TyCons.

• tcg_defaulting_plugins :: [FillDefaulting]

  A list of user-defined plugins for type defaulting plugins.

• tcg_hf_plugins :: [HoleFitPlugin]

  A list of user-defined plugins for hole fit suggestions.

• 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 :: !CompleteMatches

  Tracking indices for cost centre annotations

• tcg_cc_st :: TcRef CostCentreState
   
• tcg_next_wrapper_num :: TcRef (ModuleEnv Int)

  See Note [Generating fresh names for FFI wrappers]

Fields

• tcl_loc :: RealSrcSpan
   
• tcl_ctxt :: [ErrCtxt]
   
• tcl_in_gen_code :: Bool
   
• tcl_tclvl :: TcLevel
   
• tcl_th_ctxt :: ThStage
   
• tcl_th_bndrs :: ThBindEnv
   
• tcl_arrow_ctxt :: ArrowCtxt
   
• tcl_rdr :: LocalRdrEnv
   
• tcl_env :: TcTypeEnv
   
• tcl_usage :: TcRef UsageEnv
   
• tcl_bndrs :: TcBinderStack
   
• tcl_lie :: TcRef WantedConstraints
   
• tcl_errs :: TcRef (Messages TcRnMessage)
   

Fields

• if_doc :: SDoc
   
• if_rec_types :: KnotVars (IfG TypeEnv)
   

Fields

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

Fields

• re_loc :: !CtLoc

  In which context are we rewriting?

  Type-checking plugins might want to use this location information when emitting new Wanted constraints when rewriting type family applications. This ensures that such Wanted constraints will, when unsolved, give rise to error messages with the correct source location.

• re_flavour :: !CtFlavour
   
• re_eq_rel :: !EqRel

  At what role are we rewriting?

  See Note [Rewriter EqRels] in GHC.Tc.Solver.Rewrite

• re_rewriters :: !(TcRef RewriterSet)

  See Note [Wanteds rewrite Wanteds]

Fields

• imp_mods :: ImportedMods

  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).

• imp_direct_dep_mods :: InstalledModuleEnv ModuleNameWithIsBoot

  Home-package modules directly imported by the module being compiled.

• imp_dep_direct_pkgs :: Set UnitId

  Packages directly needed by the module being compiled

• 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

• imp_trust_pkgs :: Set UnitId

  This 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. See Note [Tracking Trust Transitively] in GHC.Rename.Names

• imp_boot_mods :: InstalledModuleEnv ModuleNameWithIsBoot

  Domain is all modules which have hs-boot files, and whether we should import the boot version of interface file. Only used in one-shot mode to populate eps_is_boot.

• imp_sig_mods :: [ModuleName]

  Signature modules below this one

• 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

• 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, InvisTVBinder)]
   
• 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 :: [InvisTVBinder]
   
• patsig_univ_bndrs :: [InvisTVBinder]
   
• patsig_req :: TcThetaType
   
• patsig_ex_bndrs :: [InvisTVBinder]
   
• patsig_prov :: TcThetaType
   
• patsig_body_ty :: TcSigmaType
   

Fields

• ns_mod_name :: ModuleName
   
• ns_exports :: [AvailInfo]
   
• ns_map :: OccEnv Name
   

Fields

• tcPluginInit :: TcPluginM s

  Initialize plugin, when entering type-checker.

• tcPluginSolve :: s -> TcPluginSolver

  Solve some constraints.

  This function will be invoked at two points in the constraint solving process: once to simplify Given constraints, and once to solve Wanted constraints. In the first case (and only in the first case), no Wanted constraints will be passed to the plugin.

  The plugin can either return a contradiction, or specify that it has solved some constraints (with evidence), and possibly emit additional constraints. These returned constraints must be Givens in the first case, and Wanteds in the second.

  Use \ _ _ _ _ _ -> pure $ TcPluginOK [] [] if your plugin does not provide this functionality.

• tcPluginRewrite :: s -> UniqFM TyCon TcPluginRewriter

  Rewrite saturated type family applications.

  The plugin is expected to supply a mapping from type family names to rewriting functions. For each type family TyCon, the plugin should provide a function which takes in the given constraints and arguments of a saturated type family application, and return a possible rewriting. See TcPluginRewriter for the expected shape of such a function.

  Use \ _ -> emptyUFM if your plugin does not provide this functionality.

• tcPluginStop :: s -> TcPluginM ()

  Clean up after the plugin, when exiting the type-checker.

Fields

• tcPluginInsolubleCts :: [Ct]

  Insoluble constraints found by the plugin.

  These constraints will be added to the inert set, and reported as insoluble to the user.

• tcPluginSolvedCts :: [(EvTerm, Ct)]

  Solved constraints, together with their evidence.

  These are removed from the inert set, and the evidence for them is recorded.

• tcPluginNewCts :: [Ct]

  New constraints that the plugin wishes to emit.

  These will be added to the work list.

Fields

• tcPluginReduction :: !Reduction
   
• tcRewriterNewWanteds :: [Ct]
   

Fields

• dePluginInit :: TcPluginM s

  Initialize plugin, when entering type-checker.

• dePluginRun :: s -> FillDefaulting

  Default some types

• dePluginStop :: s -> TcPluginM ()

  Clean up after the plugin, when exiting the type-checker.

Fields

• deProposalTyVar :: TcTyVar

  The type variable to default.

• deProposalCandidates :: [Type]

  Candidate types to default the type variable to.

• deProposalCts :: [Ct]

  The constraints against which defaults are checked.