{-# LANGUAGE DerivingStrategies         #-}
{-# LANGUAGE ExistentialQuantification  #-}
{-# LANGUAGE GADTs                      #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE PatternSynonyms            #-}

{-
(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, lclEnvInGeneratedCode,
        IfGblEnv(..), IfLclEnv(..),
        tcVisibleOrphanMods,
        RewriteEnv(..),

        -- Frontend types (shouldn't really be here)
        FrontendResult(..),

        -- Renamer types
        ErrCtxt, RecFieldEnv, pushErrCtxt, pushErrCtxtSameOrigin,
        ImportAvails(..), emptyImportAvails, plusImportAvails,
        WhereFrom(..), mkModDeps,

        -- Typechecker types
        TcTypeEnv, TcBinderStack, TcBinder(..),
        TcTyThing(..), tcTyThingTyCon_maybe,
        PromotionErr(..),
        IdBindingInfo(..), ClosedTypeId, RhsNames,
        IsGroupClosed(..),
        SelfBootInfo(..), bootExports,
        tcTyThingCategory, pprTcTyThingCategory,
        peCategory, pprPECategory,
        CompleteMatch, CompleteMatches,

        -- Template Haskell
        ThStage(..), SpliceType(..), PendingStuff(..),
        topStage, topAnnStage, topSpliceStage,
        ThLevel, impLevel, outerLevel, thLevel,
        ForeignSrcLang(..), THDocs, DocLoc(..),
        ThBindEnv,

        -- Arrows
        ArrowCtxt(..),

        -- TcSigInfo
        TcSigFun, TcSigInfo(..), TcIdSigInfo(..),
        TcIdSigInst(..), TcPatSynInfo(..),
        isPartialSig, hasCompleteSig,

        -- Misc other types
        TcId, TcIdSet,
        NameShape(..),
        removeBindingShadowing,
        getPlatform,

        -- Constraint solver plugins
        TcPlugin(..),
        TcPluginSolveResult(TcPluginContradiction, TcPluginOk, ..),
        TcPluginRewriteResult(..),
        TcPluginSolver, TcPluginRewriter,
        TcPluginM(runTcPluginM), unsafeTcPluginTcM,

        -- Defaulting plugin
        DefaultingPlugin(..), DefaultingProposal(..),
        FillDefaulting, DefaultingPluginResult,

        -- Role annotations
        RoleAnnotEnv, emptyRoleAnnotEnv, mkRoleAnnotEnv,
        lookupRoleAnnot, getRoleAnnots,

        -- Linting
        lintGblEnv,

        -- Diagnostics
        TcRnMessage
  ) where

import GHC.Prelude
import GHC.Platform

import GHC.Driver.Env
import GHC.Driver.Config.Core.Lint
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.Tc.Errors.Types

import GHC.Core.Reduction ( Reduction(..) )
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.Core.Predicate

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.Deps
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 Data.Set      ( Set )
import qualified Data.Set as S
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
import GHC.Driver.Env.KnotVars
import GHC.Linker.Types

-- | 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 intriguing 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   :: {-# UNPACK #-} !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 (Env gbl lcl -> HscEnv
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 (Env gbl lcl -> HscEnv
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 (Env gbl lcl -> HscEnv
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 = gbl -> Module
forall t. ContainsModule t => t -> Module
extractModule (Env gbl lcl -> gbl
forall gbl lcl. Env gbl lcl -> gbl
env_gbl Env gbl lcl
env)

{-
************************************************************************
*                                                                      *
*                            RewriteEnv
*                     The rewriting environment
*                                                                      *
************************************************************************
-}

-- | A 'RewriteEnv' carries the necessary context for performing rewrites
-- (i.e. type family reductions and following filled-in metavariables)
-- in the solver.
data RewriteEnv
  = RE { RewriteEnv -> CtLoc
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.

       -- Within GHC, we use this field to keep track of reduction depth.
       -- See Note [Rewriter CtLoc] in GHC.Tc.Solver.Rewrite.
       , RewriteEnv -> CtFlavour
re_flavour :: !CtFlavour
       , RewriteEnv -> EqRel
re_eq_rel  :: !EqRel
       -- ^ At what role are we rewriting?
       --
       -- See Note [Rewriter EqRels] in GHC.Tc.Solver.Rewrite

       , RewriteEnv -> TcRef RewriterSet
re_rewriters :: !(TcRef RewriterSet)  -- ^ See Note [Wanteds rewrite Wanteds]
       }
-- RewriteEnv is mostly used in @GHC.Tc.Solver.Rewrite@, but it is defined
-- here so that it can also be passed to rewriting plugins.
-- See the 'tcPluginRewrite' field of 'TcPlugin'.


{-
************************************************************************
*                                                                      *
                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 -> KnotVars (IfG TypeEnv)
if_rec_types :: (KnotVars (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 corollary 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 -> KnotVars (IORef TypeEnv)
tcg_type_env_var :: KnotVars (IORef 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 ([Linkable], PkgsLoaded)
tcg_th_needed_deps :: TcRef ([Linkable], PkgsLoaded),
          -- ^ The set of runtime dependencies required by this module
          -- See Note [Object File Dependencies]

        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 GhcRn
tcg_warns     :: (Warnings GhcRn), -- ...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 (LHsDoc GhcRn)
tcg_doc_hdr   :: Maybe (LHsDoc GhcRn), -- ^ 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
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.

        TcGblEnv -> TcRef (Messages TcRnMessage)
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

        TcGblEnv -> [TcPluginSolver]
tcg_tc_plugin_solvers :: [TcPluginSolver],
        -- ^ A list of user-defined type-checking plugins for constraint solving.

        TcGblEnv -> UniqFM TyCon [TcPluginRewriter]
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 'TyCon's.

        TcGblEnv -> [FillDefaulting]
tcg_defaulting_plugins :: [FillDefaulting],
        -- ^ A list of user-defined plugins for type defaulting plugins.

        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,

        TcGblEnv -> TcRef (ModuleEnv ThLevel)
tcg_next_wrapper_num :: TcRef (ModuleEnv Int)
        -- ^ See Note [Generating fresh names for FFI wrappers]
    }

-- 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 Module -> [Module] -> [Module]
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

bootExports :: SelfBootInfo -> NameSet
bootExports :: SelfBootInfo -> NameSet
bootExports SelfBootInfo
boot =
  case SelfBootInfo
boot of
    SelfBootInfo
NoSelfBoot -> NameSet
emptyNameSet
    SelfBoot { sb_mds :: SelfBootInfo -> ModDetails
sb_mds = ModDetails
mds} ->
      let exports :: [AvailInfo]
exports = ModDetails -> [AvailInfo]
md_exports ModDetails
mds
      in [AvailInfo] -> NameSet
availsToNameSet [AvailInfo]
exports



{- 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 untyped 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 TcRnMessage)
tcl_errs :: TcRef (Messages TcRnMessage)     -- Place to accumulate diagnostics
    }

setLclEnvTcLevel :: TcLclEnv -> TcLevel -> TcLclEnv
setLclEnvTcLevel :: TcLclEnv -> TcLevel -> TcLclEnv
setLclEnvTcLevel TcLclEnv
env TcLevel
lvl = TcLclEnv
env { tcl_tclvl = 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 = loc }

getLclEnvLoc :: TcLclEnv -> RealSrcSpan
getLclEnvLoc :: TcLclEnv -> RealSrcSpan
getLclEnvLoc = TcLclEnv -> RealSrcSpan
tcl_loc

lclEnvInGeneratedCode :: TcLclEnv -> Bool
lclEnvInGeneratedCode :: TcLclEnv -> Bool
lclEnvInGeneratedCode = TcLclEnv -> Bool
tcl_in_gen_code

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 = o, ctl_env = lcl { tcl_ctxt = err : tcl_ctxt 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 = lcl { tcl_ctxt = err : tcl_ctxt 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)           = TyVar -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyVar
id SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
brackets (TopLevelFlag -> SDoc
forall a. Outputable a => a -> SDoc
ppr TopLevelFlag
top_lvl)
   ppr (TcIdBndr_ExpType Name
id ExpType
_ TopLevelFlag
top_lvl) = Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
id SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
brackets (TopLevelFlag -> SDoc
forall a. Outputable a => a -> SDoc
ppr TopLevelFlag
top_lvl)
   ppr (TcTvBndr Name
name TyVar
tv)              = Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
name SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> TyVar -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyVar
tv

instance HasOccName TcBinder where
    occName :: TcBinder -> OccName
occName (TcIdBndr TyVar
id TopLevelFlag
_)             = Name -> OccName
forall name. HasOccName name => name -> OccName
occName (TyVar -> Name
idName TyVar
id)
    occName (TcIdBndr_ExpType Name
name ExpType
_ TopLevelFlag
_) = Name -> OccName
forall name. HasOccName name => name -> OccName
occName Name
name
    occName (TcTvBndr Name
name TyVar
_)           = Name -> OccName
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 = [a] -> [a]
forall a. [a] -> [a]
reverse ([a] -> [a]) -> [a] -> [a]
forall a b. (a -> b) -> a -> b
$ ([a], OccSet) -> [a]
forall a b. (a, b) -> a
fst (([a], OccSet) -> [a]) -> ([a], OccSet) -> [a]
forall a b. (a -> b) -> a -> b
$ (([a], OccSet) -> a -> ([a], OccSet))
-> ([a], OccSet) -> [a] -> ([a], OccSet)
forall b a. (b -> a -> b) -> b -> [a] -> b
forall (t :: * -> *) b a.
Foldable t =>
(b -> a -> b) -> b -> t a -> b
foldl
    (\([a]
bindingAcc, OccSet
seenNames) a
binding ->
    if a -> OccName
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
bindinga -> [a] -> [a]
forall a. a -> [a] -> [a]
:[a]
bindingAcc, OccSet -> OccName -> OccSet
extendOccSet OccSet
seenNames (a -> OccName
forall name. HasOccName name => name -> OccName
occName a
binding)))
    ([], OccSet
emptyOccSet) [a]
bindings


-- | Get target platform
getPlatform :: TcRnIf a b Platform
getPlatform :: forall a b. TcRnIf a b Platform
getPlatform = DynFlags -> Platform
targetPlatform (DynFlags -> Platform)
-> IOEnv (Env a b) DynFlags -> IOEnv (Env a b) Platform
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> IOEnv (Env a b) DynFlags
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
forall doc. IsLine doc => FilePath -> doc
text FilePath
"Splice"
   ppr (RunSplice TcRef [ForeignRef (Q ())]
_) = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"RunSplice"
   ppr ThStage
Comp          = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"Comp"
   ppr (Brack ThStage
s PendingStuff
_)   = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"Brack" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
parens (ThStage -> SDoc
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 ThLevel -> ThLevel -> ThLevel
forall a. Num a => a -> a -> a
+ ThLevel
1
thLevel (RunSplice TcRef [ForeignRef (Q ())]
_) = FilePath -> ThLevel
forall a. HasCallStack => FilePath -> a
panic FilePath
"thLevel: called when running a splice"
                        -- See Note [RunSplice ThLevel].

{- Note [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 classes 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

-- | Matches on either a global 'TyCon' or a 'TcTyCon'.
tcTyThingTyCon_maybe :: TcTyThing -> Maybe TyCon
tcTyThingTyCon_maybe :: TcTyThing -> Maybe TyCon
tcTyThingTyCon_maybe (AGlobal (ATyCon TyCon
tc)) = TyCon -> Maybe TyCon
forall a. a -> Maybe a
Just TyCon
tc
tcTyThingTyCon_maybe (ATcTyCon TyCon
tc_tc)      = TyCon -> Maybe TyCon
forall a. a -> Maybe a
Just TyCon
tc_tc
tcTyThingTyCon_maybe TcTyThing
_                     = Maybe TyCon
forall a. Maybe a
Nothing

instance Outputable TcTyThing where     -- Debugging only
   ppr :: TcTyThing -> SDoc
ppr (AGlobal TyThing
g)      = TyThing -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyThing
g
   ppr elt :: TcTyThing
elt@(ATcId {})   = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"Identifier" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<>
                          SDoc -> SDoc
forall doc. IsLine doc => doc -> doc
brackets (TyVar -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TcTyThing -> TyVar
tct_id TcTyThing
elt) SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc
dcolon
                                 SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> Type -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyVar -> Type
varType (TcTyThing -> TyVar
tct_id TcTyThing
elt)) SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<> SDoc
forall doc. IsLine doc => doc
comma
                                 SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> IdBindingInfo -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TcTyThing -> IdBindingInfo
tct_info TcTyThing
elt))
   ppr (ATyVar Name
n TyVar
tv)    = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"Type variable" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> SDoc -> SDoc
quotes (Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
n) SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> SDoc
forall doc. IsLine doc => doc
equals SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> TyVar -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyVar
tv
                            SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> SDoc
dcolon SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> Type -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyVar -> Type
varType TyVar
tv)
   ppr (ATcTyCon TyCon
tc)    = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"ATcTyCon" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
tc SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> SDoc
dcolon SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> Type -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyCon -> Type
tyConKind TyCon
tc)
   ppr (APromotionErr PromotionErr
err) = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"APromotionErr" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> PromotionErr -> 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]
    = 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 group
                          -- 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]

{- 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: ClosedTypeId]

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
forall doc. IsLine doc => FilePath -> doc
text FilePath
"NotLetBound"
  ppr IdBindingInfo
ClosedLet = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"TopLevelLet"
  ppr (NonClosedLet NameSet
fvs Bool
closed_type) =
    FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"TopLevelLet" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> NameSet -> SDoc
forall a. Outputable a => a -> SDoc
ppr NameSet
fvs SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> Bool -> SDoc
forall a. Outputable a => a -> SDoc
ppr Bool
closed_type

--------------
pprTcTyThingCategory :: TcTyThing -> SDoc
pprTcTyThingCategory :: TcTyThing -> SDoc
pprTcTyThingCategory = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text (FilePath -> SDoc) -> (TcTyThing -> FilePath) -> TcTyThing -> SDoc
forall b c a. (b -> c) -> (a -> b) -> a -> c
. FilePath -> FilePath
capitalise (FilePath -> FilePath)
-> (TcTyThing -> FilePath) -> TcTyThing -> FilePath
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

{-
************************************************************************
*                                                                      *
        Operations over ImportAvails
*                                                                      *
************************************************************************
-}


mkModDeps :: Set (UnitId, ModuleNameWithIsBoot)
          -> InstalledModuleEnv ModuleNameWithIsBoot
mkModDeps :: Set (UnitId, ModuleNameWithIsBoot)
-> InstalledModuleEnv ModuleNameWithIsBoot
mkModDeps Set (UnitId, ModuleNameWithIsBoot)
deps = (InstalledModuleEnv ModuleNameWithIsBoot
 -> (UnitId, ModuleNameWithIsBoot)
 -> InstalledModuleEnv ModuleNameWithIsBoot)
-> InstalledModuleEnv ModuleNameWithIsBoot
-> Set (UnitId, ModuleNameWithIsBoot)
-> InstalledModuleEnv ModuleNameWithIsBoot
forall a b. (a -> b -> a) -> a -> Set b -> a
S.foldl' InstalledModuleEnv ModuleNameWithIsBoot
-> (UnitId, ModuleNameWithIsBoot)
-> InstalledModuleEnv ModuleNameWithIsBoot
add InstalledModuleEnv ModuleNameWithIsBoot
forall a. InstalledModuleEnv a
emptyInstalledModuleEnv Set (UnitId, ModuleNameWithIsBoot)
deps
  where
    add :: InstalledModuleEnv ModuleNameWithIsBoot
-> (UnitId, ModuleNameWithIsBoot)
-> InstalledModuleEnv ModuleNameWithIsBoot
add InstalledModuleEnv ModuleNameWithIsBoot
env (UnitId
uid, ModuleNameWithIsBoot
elt) = InstalledModuleEnv ModuleNameWithIsBoot
-> InstalledModule
-> ModuleNameWithIsBoot
-> InstalledModuleEnv ModuleNameWithIsBoot
forall a.
InstalledModuleEnv a
-> InstalledModule -> a -> InstalledModuleEnv a
extendInstalledModuleEnv InstalledModuleEnv ModuleNameWithIsBoot
env (UnitId -> ModuleName -> InstalledModule
forall u. u -> ModuleName -> GenModule u
mkModule UnitId
uid (ModuleNameWithIsBoot -> ModuleName
forall mod. GenWithIsBoot mod -> mod
gwib_mod ModuleNameWithIsBoot
elt)) ModuleNameWithIsBoot
elt

plusModDeps :: InstalledModuleEnv ModuleNameWithIsBoot
            -> InstalledModuleEnv ModuleNameWithIsBoot
            -> InstalledModuleEnv ModuleNameWithIsBoot
plusModDeps :: InstalledModuleEnv ModuleNameWithIsBoot
-> InstalledModuleEnv ModuleNameWithIsBoot
-> InstalledModuleEnv ModuleNameWithIsBoot
plusModDeps = (ModuleNameWithIsBoot
 -> ModuleNameWithIsBoot -> ModuleNameWithIsBoot)
-> InstalledModuleEnv ModuleNameWithIsBoot
-> InstalledModuleEnv ModuleNameWithIsBoot
-> InstalledModuleEnv ModuleNameWithIsBoot
forall elt.
(elt -> elt -> elt)
-> InstalledModuleEnv elt
-> InstalledModuleEnv elt
-> InstalledModuleEnv elt
plusInstalledModuleEnv ModuleNameWithIsBoot
-> ModuleNameWithIsBoot -> ModuleNameWithIsBoot
forall {a}.
(Eq a, Outputable a) =>
GenWithIsBoot a -> GenWithIsBoot a -> GenWithIsBoot a
plus_mod_dep
  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})
      | Bool -> SDoc -> IsBootInterface -> IsBootInterface
forall a. HasCallStack => Bool -> SDoc -> a -> a
assertPpr (a
m1 a -> a -> Bool
forall a. Eq a => a -> a -> Bool
== a
m2) ((a -> SDoc
forall a. Outputable a => a -> SDoc
ppr a
m1 SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> a -> SDoc
forall a. Outputable a => a -> SDoc
ppr a
m2) SDoc -> SDoc -> SDoc
forall doc. IsDoc doc => doc -> doc -> doc
$$ (Bool -> SDoc
forall a. Outputable a => a -> SDoc
ppr (IsBootInterface
boot1 IsBootInterface -> IsBootInterface -> Bool
forall a. Eq a => a -> a -> Bool
== IsBootInterface
IsBoot) SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> Bool -> SDoc
forall a. Outputable a => a -> SDoc
ppr (IsBootInterface
boot2 IsBootInterface -> IsBootInterface -> Bool
forall a. Eq a => a -> a -> Bool
== IsBootInterface
IsBoot)))
        IsBootInterface
boot1 IsBootInterface -> IsBootInterface -> Bool
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

emptyImportAvails :: ImportAvails
emptyImportAvails :: ImportAvails
emptyImportAvails = ImportAvails { imp_mods :: ImportedMods
imp_mods          = ImportedMods
forall a. ModuleEnv a
emptyModuleEnv,
                                   imp_direct_dep_mods :: InstalledModuleEnv ModuleNameWithIsBoot
imp_direct_dep_mods = InstalledModuleEnv ModuleNameWithIsBoot
forall a. InstalledModuleEnv a
emptyInstalledModuleEnv,
                                   imp_dep_direct_pkgs :: Set UnitId
imp_dep_direct_pkgs = Set UnitId
forall a. Set a
S.empty,
                                   imp_sig_mods :: [ModuleName]
imp_sig_mods      = [],
                                   imp_trust_pkgs :: Set UnitId
imp_trust_pkgs    = Set UnitId
forall a. Set a
S.empty,
                                   imp_trust_own_pkg :: Bool
imp_trust_own_pkg = Bool
False,
                                   imp_boot_mods :: InstalledModuleEnv ModuleNameWithIsBoot
imp_boot_mods   = InstalledModuleEnv ModuleNameWithIsBoot
forall a. InstalledModuleEnv a
emptyInstalledModuleEnv,
                                   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_direct_dep_mods :: ImportAvails -> InstalledModuleEnv ModuleNameWithIsBoot
imp_direct_dep_mods = InstalledModuleEnv ModuleNameWithIsBoot
ddmods1,
                  imp_dep_direct_pkgs :: ImportAvails -> Set UnitId
imp_dep_direct_pkgs = Set UnitId
ddpkgs1,
                  imp_boot_mods :: ImportAvails -> InstalledModuleEnv ModuleNameWithIsBoot
imp_boot_mods = InstalledModuleEnv ModuleNameWithIsBoot
srs1,
                  imp_sig_mods :: ImportAvails -> [ModuleName]
imp_sig_mods = [ModuleName]
sig_mods1,
                  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_direct_dep_mods :: ImportAvails -> InstalledModuleEnv ModuleNameWithIsBoot
imp_direct_dep_mods = InstalledModuleEnv ModuleNameWithIsBoot
ddmods2,
                  imp_dep_direct_pkgs :: ImportAvails -> Set UnitId
imp_dep_direct_pkgs = Set UnitId
ddpkgs2,
                  imp_boot_mods :: ImportAvails -> InstalledModuleEnv ModuleNameWithIsBoot
imp_boot_mods = InstalledModuleEnv ModuleNameWithIsBoot
srcs2,
                  imp_sig_mods :: ImportAvails -> [ModuleName]
imp_sig_mods = [ModuleName]
sig_mods2,
                  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          = ([ImportedBy] -> [ImportedBy] -> [ImportedBy])
-> ImportedMods -> ImportedMods -> ImportedMods
forall a.
(a -> a -> a) -> ModuleEnv a -> ModuleEnv a -> ModuleEnv a
plusModuleEnv_C [ImportedBy] -> [ImportedBy] -> [ImportedBy]
forall a. [a] -> [a] -> [a]
(++) ImportedMods
mods1 ImportedMods
mods2,
                   imp_direct_dep_mods :: InstalledModuleEnv ModuleNameWithIsBoot
imp_direct_dep_mods = InstalledModuleEnv ModuleNameWithIsBoot
ddmods1 InstalledModuleEnv ModuleNameWithIsBoot
-> InstalledModuleEnv ModuleNameWithIsBoot
-> InstalledModuleEnv ModuleNameWithIsBoot
`plusModDeps` InstalledModuleEnv ModuleNameWithIsBoot
ddmods2,
                   imp_dep_direct_pkgs :: Set UnitId
imp_dep_direct_pkgs      = Set UnitId
ddpkgs1 Set UnitId -> Set UnitId -> Set UnitId
forall a. Ord a => Set a -> Set a -> Set a
`S.union` Set UnitId
ddpkgs2,
                   imp_trust_pkgs :: Set UnitId
imp_trust_pkgs    = Set UnitId
tpkgs1 Set UnitId -> Set UnitId -> Set UnitId
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_boot_mods :: InstalledModuleEnv ModuleNameWithIsBoot
imp_boot_mods   = InstalledModuleEnv ModuleNameWithIsBoot
srs1 InstalledModuleEnv ModuleNameWithIsBoot
-> InstalledModuleEnv ModuleNameWithIsBoot
-> InstalledModuleEnv ModuleNameWithIsBoot
`plusModDeps` InstalledModuleEnv ModuleNameWithIsBoot
srcs2,
                   imp_sig_mods :: [ModuleName]
imp_sig_mods      = [ModuleName] -> [ModuleName] -> [ModuleName]
forall a.
(() :: Constraint, Outputable a, Ord a) =>
[a] -> [a] -> [a]
unionListsOrd [ModuleName]
sig_mods1 [ModuleName]
sig_mods2,
                   imp_orphs :: [Module]
imp_orphs         = [Module] -> [Module] -> [Module]
forall a.
(() :: Constraint, Outputable a, Ord a) =>
[a] -> [a] -> [a]
unionListsOrd [Module]
orphs1 [Module]
orphs2,
                   imp_finsts :: [Module]
imp_finsts        = [Module] -> [Module] -> [Module]
forall a.
(() :: Constraint, Outputable a, Ord a) =>
[a] -> [a] -> [a]
unionListsOrd [Module]
finsts1 [Module]
finsts2 }

{-
************************************************************************
*                                                                      *
\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
forall doc. IsLine doc => FilePath -> doc
text FilePath
"{- SOURCE -}"
  ppr (ImportByUser IsBootInterface
NotBoot)               = SDoc
forall doc. IsOutput doc => doc
empty
  ppr WhereFrom
ImportBySystem                       = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"{- SYSTEM -}"
  ppr WhereFrom
ImportByPlugin                       = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
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) = TcIdSigInfo -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcIdSigInfo
idsi
  ppr (TcPatSynSig TcPatSynInfo
tpsi) = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"TcPatSynInfo" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> TcPatSynInfo -> 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 })
        = TyVar -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyVar
bndr SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> SDoc
dcolon SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> Type -> 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
forall doc. IsLine doc => FilePath -> doc
text FilePath
"psig" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
name SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> SDoc
dcolon SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> HsWildCardBndrs GhcRn (GenLocated SrcSpanAnnA (HsSigType GhcRn))
-> SDoc
forall a. Outputable a => a -> SDoc
ppr LHsSigWcType GhcRn
HsWildCardBndrs GhcRn (GenLocated SrcSpanAnnA (HsSigType 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 (TcIdSigInfo -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcIdSigInfo
sig) ThLevel
2 ([SDoc] -> SDoc
forall doc. IsDoc doc => [doc] -> doc
vcat [ [(Name, InvisTVBinder)] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [(Name, InvisTVBinder)]
skols, [Type] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Type]
theta SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> SDoc
darrow SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> Type -> 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}) = Name -> SDoc
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
-------------------------
-}

-- | The @solve@ function of a type-checking plugin takes in Given
-- and Wanted constraints, and should return a 'TcPluginSolveResult'
-- indicating which Wanted constraints it could solve, or whether any are
-- insoluble.
type TcPluginSolver = EvBindsVar
                   -> [Ct] -- ^ Givens
                   -> [Ct] -- ^ Wanteds
                   -> TcPluginM TcPluginSolveResult

-- | For rewriting type family applications, a type-checking plugin provides
-- a function of this type for each type family 'TyCon'.
--
-- The function is provided with the current set of Given constraints, together
-- with the arguments to the type family.
-- The type family application will always be fully saturated.
type TcPluginRewriter
  =  RewriteEnv -- ^ Rewriter environment
  -> [Ct]       -- ^ Givens
  -> [TcType]   -- ^ type family arguments
  -> TcPluginM TcPluginRewriteResult

-- | 'TcPluginM' is the monad in which type-checking plugins operate.
newtype TcPluginM a = TcPluginM { forall a. TcPluginM a -> TcM a
runTcPluginM :: TcM a }
  deriving newtype ((forall a b. (a -> b) -> TcPluginM a -> TcPluginM b)
-> (forall a b. a -> TcPluginM b -> TcPluginM a)
-> Functor TcPluginM
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
$cfmap :: forall a b. (a -> b) -> TcPluginM a -> TcPluginM b
fmap :: forall a b. (a -> b) -> TcPluginM a -> TcPluginM b
$c<$ :: forall a b. a -> TcPluginM b -> TcPluginM a
<$ :: forall a b. a -> TcPluginM b -> TcPluginM a
Functor, Functor TcPluginM
Functor TcPluginM =>
(forall a. a -> TcPluginM a)
-> (forall a b. TcPluginM (a -> b) -> TcPluginM a -> TcPluginM b)
-> (forall a b c.
    (a -> b -> c) -> TcPluginM a -> TcPluginM b -> TcPluginM c)
-> (forall a b. TcPluginM a -> TcPluginM b -> TcPluginM b)
-> (forall a b. TcPluginM a -> TcPluginM b -> TcPluginM a)
-> Applicative TcPluginM
forall a. a -> TcPluginM a
forall a b. TcPluginM a -> TcPluginM b -> TcPluginM a
forall a b. TcPluginM a -> TcPluginM b -> TcPluginM b
forall a b. TcPluginM (a -> b) -> TcPluginM a -> TcPluginM b
forall a b c.
(a -> b -> c) -> TcPluginM a -> TcPluginM b -> TcPluginM c
forall (f :: * -> *).
Functor f =>
(forall a. a -> f a)
-> (forall a b. f (a -> b) -> f a -> f b)
-> (forall a b c. (a -> b -> c) -> f a -> f b -> f c)
-> (forall a b. f a -> f b -> f b)
-> (forall a b. f a -> f b -> f a)
-> Applicative f
$cpure :: forall a. a -> TcPluginM a
pure :: forall a. a -> TcPluginM a
$c<*> :: forall a b. TcPluginM (a -> b) -> TcPluginM a -> TcPluginM b
<*> :: forall a b. TcPluginM (a -> b) -> TcPluginM a -> TcPluginM b
$cliftA2 :: forall a b c.
(a -> b -> c) -> TcPluginM a -> TcPluginM b -> TcPluginM c
liftA2 :: forall a b c.
(a -> b -> c) -> TcPluginM a -> TcPluginM b -> TcPluginM c
$c*> :: forall a b. TcPluginM a -> TcPluginM b -> TcPluginM b
*> :: forall a b. TcPluginM a -> TcPluginM b -> TcPluginM b
$c<* :: forall a b. TcPluginM a -> TcPluginM b -> TcPluginM a
<* :: forall a b. TcPluginM a -> TcPluginM b -> TcPluginM a
Applicative, Applicative TcPluginM
Applicative TcPluginM =>
(forall a b. TcPluginM a -> (a -> TcPluginM b) -> TcPluginM b)
-> (forall a b. TcPluginM a -> TcPluginM b -> TcPluginM b)
-> (forall a. a -> TcPluginM a)
-> Monad TcPluginM
forall a. a -> TcPluginM a
forall a b. TcPluginM a -> TcPluginM b -> TcPluginM b
forall a b. TcPluginM a -> (a -> TcPluginM b) -> TcPluginM b
forall (m :: * -> *).
Applicative m =>
(forall a b. m a -> (a -> m b) -> m b)
-> (forall a b. m a -> m b -> m b)
-> (forall a. a -> m a)
-> Monad m
$c>>= :: forall a b. TcPluginM a -> (a -> TcPluginM b) -> TcPluginM b
>>= :: forall a b. TcPluginM a -> (a -> TcPluginM b) -> TcPluginM b
$c>> :: forall a b. TcPluginM a -> TcPluginM b -> TcPluginM b
>> :: forall a b. TcPluginM a -> TcPluginM b -> TcPluginM b
$creturn :: forall a. a -> TcPluginM a
return :: forall a. a -> TcPluginM a
Monad, Monad TcPluginM
Monad TcPluginM =>
(forall a. FilePath -> TcPluginM a) -> MonadFail TcPluginM
forall a. FilePath -> TcPluginM a
forall (m :: * -> *).
Monad m =>
(forall a. FilePath -> m a) -> MonadFail m
$cfail :: forall a. FilePath -> TcPluginM a
fail :: forall a. FilePath -> TcPluginM a
MonadFail)

-- | 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 = TcM a -> TcPluginM a
forall a. TcM a -> TcPluginM a
TcPluginM

data TcPlugin = forall s. TcPlugin
  { ()
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.
  }

-- | The plugin found a contradiction.
-- The returned constraints are removed from the inert set,
-- and recorded as insoluble.
--
-- The returned list of constraints should never be empty.
pattern TcPluginContradiction :: [Ct] -> TcPluginSolveResult
pattern $mTcPluginContradiction :: forall {r}. TcPluginSolveResult -> ([Ct] -> r) -> ((# #) -> r) -> r
$bTcPluginContradiction :: [Ct] -> TcPluginSolveResult
TcPluginContradiction insols
  = TcPluginSolveResult
  { tcPluginInsolubleCts = insols
  , tcPluginSolvedCts    = []
  , tcPluginNewCts       = [] }

-- | The plugin has not found any contradictions,
--
-- The first field is for constraints that were solved.
-- The second field contains new work, that should be processed by
-- the constraint solver.
pattern TcPluginOk :: [(EvTerm, Ct)] -> [Ct] -> TcPluginSolveResult
pattern $mTcPluginOk :: forall {r}.
TcPluginSolveResult
-> ([(EvTerm, Ct)] -> [Ct] -> r) -> ((# #) -> r) -> r
$bTcPluginOk :: [(EvTerm, Ct)] -> [Ct] -> TcPluginSolveResult
TcPluginOk solved new
  = TcPluginSolveResult
  { tcPluginInsolubleCts = []
  , tcPluginSolvedCts    = solved
  , tcPluginNewCts       = new }

-- | Result of running a solver plugin.
data TcPluginSolveResult
  = TcPluginSolveResult
  { -- | Insoluble constraints found by the plugin.
    --
    -- These constraints will be added to the inert set,
    -- and reported as insoluble to the user.
    TcPluginSolveResult -> [Ct]
tcPluginInsolubleCts :: [Ct]
    -- | Solved constraints, together with their evidence.
    --
    -- These are removed from the inert set, and the
    -- evidence for them is recorded.
  , TcPluginSolveResult -> [(EvTerm, Ct)]
tcPluginSolvedCts :: [(EvTerm, Ct)]
    -- | New constraints that the plugin wishes to emit.
    --
    -- These will be added to the work list.
  , TcPluginSolveResult -> [Ct]
tcPluginNewCts :: [Ct]
  }

data TcPluginRewriteResult
  =
  -- | The plugin does not rewrite the type family application.
    TcPluginNoRewrite

  -- | The plugin rewrites the type family application
  -- providing a rewriting together with evidence: a 'Reduction',
  -- which contains the rewritten type together with a 'Coercion'
  -- whose right-hand-side type is the rewritten type.
  --
  -- The plugin can also emit additional Wanted constraints.
  | TcPluginRewriteTo
    { TcPluginRewriteResult -> Reduction
tcPluginReduction    :: !Reduction
    , TcPluginRewriteResult -> [Ct]
tcRewriterNewWanteds :: [Ct]
    }

-- | A collection of candidate default types for a type variable.
data DefaultingProposal
  = DefaultingProposal
    { DefaultingProposal -> TyVar
deProposalTyVar :: TcTyVar
      -- ^ The type variable to default.
    , DefaultingProposal -> [Type]
deProposalCandidates :: [Type]
      -- ^ Candidate types to default the type variable to.
    , DefaultingProposal -> [Ct]
deProposalCts :: [Ct]
      -- ^ The constraints against which defaults are checked.
    }

instance Outputable DefaultingProposal where
  ppr :: DefaultingProposal -> SDoc
ppr DefaultingProposal
p = FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
text FilePath
"DefaultingProposal"
          SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> TyVar -> SDoc
forall a. Outputable a => a -> SDoc
ppr (DefaultingProposal -> TyVar
deProposalTyVar DefaultingProposal
p)
          SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> [Type] -> SDoc
forall a. Outputable a => a -> SDoc
ppr (DefaultingProposal -> [Type]
deProposalCandidates DefaultingProposal
p)
          SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> [Ct] -> SDoc
forall a. Outputable a => a -> SDoc
ppr (DefaultingProposal -> [Ct]
deProposalCts DefaultingProposal
p)

type DefaultingPluginResult = [DefaultingProposal]
type FillDefaulting
  = WantedConstraints
      -- Zonked constraints containing the unfilled metavariables that
      -- can be defaulted. See wrinkle (DP1) of Note [Defaulting plugins]
      -- in GHC.Tc.Solver
  -> TcPluginM [DefaultingProposal]

-- | A plugin for controlling defaulting.
data DefaultingPlugin = forall s. DefaultingPlugin
  { ()
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.
  }

{- *********************************************************************
*                                                                      *
                        Role annotations
*                                                                      *
********************************************************************* -}

type RoleAnnotEnv = NameEnv (LRoleAnnotDecl GhcRn)

mkRoleAnnotEnv :: [LRoleAnnotDecl GhcRn] -> RoleAnnotEnv
mkRoleAnnotEnv :: [LRoleAnnotDecl GhcRn] -> RoleAnnotEnv
mkRoleAnnotEnv [LRoleAnnotDecl GhcRn]
role_annot_decls
 = [(Name, GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn))]
-> NameEnv (GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn))
forall a. [(Name, a)] -> NameEnv a
mkNameEnv [ (IdP GhcRn
Name
name, GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn)
ra_decl)
             | GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn)
ra_decl <- [LRoleAnnotDecl GhcRn]
[GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn)]
role_annot_decls
             , let name :: IdP GhcRn
name = RoleAnnotDecl GhcRn -> IdP GhcRn
forall (p :: Pass). RoleAnnotDecl (GhcPass p) -> IdP (GhcPass p)
roleAnnotDeclName (GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn) -> RoleAnnotDecl GhcRn
forall l e. GenLocated l e -> e
unLoc GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn)
ra_decl)
             , Bool -> Bool
not (Name -> Bool
isUnboundName IdP GhcRn
Name
name) ]
       -- Some of the role annots will be unbound;
       -- we don't wish to include these

emptyRoleAnnotEnv :: RoleAnnotEnv
emptyRoleAnnotEnv :: RoleAnnotEnv
emptyRoleAnnotEnv = RoleAnnotEnv
NameEnv (GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn))
forall a. NameEnv a
emptyNameEnv

lookupRoleAnnot :: RoleAnnotEnv -> Name -> Maybe (LRoleAnnotDecl GhcRn)
lookupRoleAnnot :: RoleAnnotEnv -> Name -> Maybe (LRoleAnnotDecl GhcRn)
lookupRoleAnnot = RoleAnnotEnv -> Name -> Maybe (LRoleAnnotDecl GhcRn)
NameEnv (GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn))
-> Name -> Maybe (GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn))
forall a. NameEnv a -> Name -> Maybe a
lookupNameEnv

getRoleAnnots :: [Name] -> RoleAnnotEnv -> [LRoleAnnotDecl GhcRn]
getRoleAnnots :: [Name] -> RoleAnnotEnv -> [LRoleAnnotDecl GhcRn]
getRoleAnnots [Name]
bndrs RoleAnnotEnv
role_env
  = (Name -> Maybe (GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn)))
-> [Name] -> [GenLocated SrcSpanAnnA (RoleAnnotDecl GhcRn)]
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 =
  -- TODO empty list means no extra in scope from GHCi, is this correct?
  IO () -> TcM ()
forall a. IO a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. MonadIO m => IO a -> m a
liftIO (IO () -> TcM ()) -> IO () -> TcM ()
forall a b. (a -> b) -> a -> b
$ Logger -> LintConfig -> SDoc -> [CoAxiom Branched] -> IO ()
lintAxioms Logger
logger (DynFlags -> [TyVar] -> LintConfig
initLintConfig DynFlags
dflags []) (FilePath -> SDoc
forall doc. IsLine doc => FilePath -> doc
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
(DocLoc -> DocLoc -> Bool)
-> (DocLoc -> DocLoc -> Bool) -> Eq DocLoc
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
$c== :: DocLoc -> DocLoc -> Bool
== :: DocLoc -> DocLoc -> Bool
$c/= :: DocLoc -> DocLoc -> Bool
/= :: DocLoc -> DocLoc -> Bool
Eq, Eq DocLoc
Eq DocLoc =>
(DocLoc -> DocLoc -> Ordering)
-> (DocLoc -> DocLoc -> Bool)
-> (DocLoc -> DocLoc -> Bool)
-> (DocLoc -> DocLoc -> Bool)
-> (DocLoc -> DocLoc -> Bool)
-> (DocLoc -> DocLoc -> DocLoc)
-> (DocLoc -> DocLoc -> DocLoc)
-> Ord DocLoc
DocLoc -> DocLoc -> Bool
DocLoc -> DocLoc -> Ordering
DocLoc -> DocLoc -> DocLoc
forall a.
Eq a =>
(a -> a -> Ordering)
-> (a -> a -> Bool)
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-> Ord a
$ccompare :: DocLoc -> DocLoc -> Ordering
compare :: DocLoc -> DocLoc -> Ordering
$c< :: DocLoc -> DocLoc -> Bool
< :: DocLoc -> DocLoc -> Bool
$c<= :: DocLoc -> DocLoc -> Bool
<= :: DocLoc -> DocLoc -> Bool
$c> :: DocLoc -> DocLoc -> Bool
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$c>= :: DocLoc -> DocLoc -> Bool
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$cmax :: DocLoc -> DocLoc -> DocLoc
max :: DocLoc -> DocLoc -> DocLoc
$cmin :: DocLoc -> DocLoc -> DocLoc
min :: DocLoc -> DocLoc -> DocLoc
Ord)

-- | The current collection of docs that Template Haskell has built up via
-- putDoc.
type THDocs = Map DocLoc (HsDoc GhcRn)