{-# LANGUAGE FlexibleContexts    #-}
{-# LANGUAGE RankNTypes          #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeApplications    #-}
{-# LANGUAGE TypeFamilies        #-}

{-
(c) The University of Glasgow 2006
(c) The GRASP/AQUA Project, Glasgow University, 1992-1998

-}

module GHC.Tc.Gen.Bind
   ( tcLocalBinds
   , tcTopBinds
   , tcValBinds
   , tcHsBootSigs
   , tcPolyCheck
   , chooseInferredQuantifiers
   )
where

import GHC.Prelude

import {-# SOURCE #-} GHC.Tc.Gen.Match ( tcGRHSsPat, tcMatchesFun )
import {-# SOURCE #-} GHC.Tc.Gen.Expr  ( tcCheckMonoExpr )
import {-# SOURCE #-} GHC.Tc.TyCl.PatSyn ( tcPatSynDecl, tcPatSynBuilderBind )

import GHC.Types.Tickish (CoreTickish, GenTickish (..))
import GHC.Types.CostCentre (mkUserCC, CCFlavour(DeclCC))
import GHC.Driver.Session
import GHC.Data.FastString
import GHC.Hs
import GHC.Tc.Errors.Types
import GHC.Tc.Gen.Sig
import GHC.Tc.Utils.Concrete ( hasFixedRuntimeRep_syntactic )
import GHC.Tc.Utils.Monad
import GHC.Tc.Types.Origin
import GHC.Tc.Utils.Env
import GHC.Tc.Utils.Unify
import GHC.Tc.Solver
import GHC.Tc.Types.Evidence
import GHC.Tc.Types.Constraint
import GHC.Core.Predicate
import GHC.Tc.Gen.HsType
import GHC.Tc.Gen.Pat
import GHC.Tc.Utils.TcMType
import GHC.Core.Reduction ( Reduction(..) )
import GHC.Core.Multiplicity
import GHC.Core.FamInstEnv( normaliseType )
import GHC.Tc.Instance.Family( tcGetFamInstEnvs )
import GHC.Core.Class   ( Class )
import GHC.Tc.Utils.TcType
import GHC.Core.Type (mkStrLitTy, tidyOpenType, mkCastTy)
import GHC.Builtin.Types ( mkBoxedTupleTy )
import GHC.Builtin.Types.Prim
import GHC.Types.SourceText
import GHC.Types.Id
import GHC.Types.Var as Var
import GHC.Types.Var.Set
import GHC.Types.Var.Env( TidyEnv )
import GHC.Unit.Module
import GHC.Types.Name
import GHC.Types.Name.Set
import GHC.Types.Name.Env
import GHC.Types.SrcLoc
import GHC.Data.Bag
import GHC.Utils.Error
import GHC.Data.Graph.Directed
import GHC.Data.Maybe
import GHC.Utils.Misc
import GHC.Types.Basic
import GHC.Types.CompleteMatch
import GHC.Utils.Outputable as Outputable
import GHC.Utils.Panic
import GHC.Builtin.Names( ipClassName )
import GHC.Tc.Validity (checkValidType)
import GHC.Types.Unique.FM
import GHC.Types.Unique.DSet
import GHC.Types.Unique.Set
import qualified GHC.LanguageExtensions as LangExt

import Control.Monad
import Data.Foldable (find)

{-
************************************************************************
*                                                                      *
\subsection{Type-checking bindings}
*                                                                      *
************************************************************************

@tcBindsAndThen@ typechecks a @HsBinds@.  The "and then" part is because
it needs to know something about the {\em usage} of the things bound,
so that it can create specialisations of them.  So @tcBindsAndThen@
takes a function which, given an extended environment, E, typechecks
the scope of the bindings returning a typechecked thing and (most
important) an LIE.  It is this LIE which is then used as the basis for
specialising the things bound.

@tcBindsAndThen@ also takes a "combiner" which glues together the
bindings and the "thing" to make a new "thing".

The real work is done by @tcBindWithSigsAndThen@.

Recursive and non-recursive binds are handled in essentially the same
way: because of uniques there are no scoping issues left.  The only
difference is that non-recursive bindings can bind primitive values.

Even for non-recursive binding groups we add typings for each binder
to the LVE for the following reason.  When each individual binding is
checked the type of its LHS is unified with that of its RHS; and
type-checking the LHS of course requires that the binder is in scope.

At the top-level the LIE is sure to contain nothing but constant
dictionaries, which we resolve at the module level.

Note [Polymorphic recursion]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The game plan for polymorphic recursion in the code above is

        * Bind any variable for which we have a type signature
          to an Id with a polymorphic type.  Then when type-checking
          the RHSs we'll make a full polymorphic call.

This fine, but if you aren't a bit careful you end up with a horrendous
amount of partial application and (worse) a huge space leak. For example:

        f :: Eq a => [a] -> [a]
        f xs = ...f...

If we don't take care, after typechecking we get

        f = /\a -> \d::Eq a -> let f' = f a d
                               in
                               \ys:[a] -> ...f'...

Notice the stupid construction of (f a d), which is of course
identical to the function we're executing.  In this case, the
polymorphic recursion isn't being used (but that's a very common case).
This can lead to a massive space leak, from the following top-level defn
(post-typechecking)

        ff :: [Int] -> [Int]
        ff = f Int dEqInt

Now (f dEqInt) evaluates to a lambda that has f' as a free variable; but
f' is another thunk which evaluates to the same thing... and you end
up with a chain of identical values all hung onto by the CAF ff.

        ff = f Int dEqInt

           = let f' = f Int dEqInt in \ys. ...f'...

           = let f' = let f' = f Int dEqInt in \ys. ...f'...
                      in \ys. ...f'...

Etc.

NOTE: a bit of arity analysis would push the (f a d) inside the (\ys...),
which would make the space leak go away in this case

Solution: when typechecking the RHSs we always have in hand the
*monomorphic* Ids for each binding.  So we just need to make sure that
if (Method f a d) shows up in the constraints emerging from (...f...)
we just use the monomorphic Id.  We achieve this by adding monomorphic Ids
to the "givens" when simplifying constraints.  That's what the "lies_avail"
is doing.

Then we get

        f = /\a -> \d::Eq a -> letrec
                                 fm = \ys:[a] -> ...fm...
                               in
                               fm
-}

tcTopBinds :: [(RecFlag, LHsBinds GhcRn)] -> [LSig GhcRn]
           -> TcM (TcGblEnv, TcLclEnv)
-- The TcGblEnv contains the new tcg_binds and tcg_spects
-- The TcLclEnv has an extended type envt for the new bindings
tcTopBinds :: [(RecFlag, LHsBinds GhcRn)]
-> [LSig GhcRn] -> TcM (TcGblEnv, TcLclEnv)
tcTopBinds [(RecFlag, LHsBinds GhcRn)]
binds [LSig GhcRn]
sigs
  = do  { -- Pattern synonym bindings populate the global environment
          ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
binds', (TcGblEnv
tcg_env, TcLclEnv
tcl_env)) <- TopLevelFlag
-> [(RecFlag, LHsBinds GhcRn)]
-> [LSig GhcRn]
-> TcM (TcGblEnv, TcLclEnv)
-> TcM ([(RecFlag, LHsBinds GhcTc)], (TcGblEnv, TcLclEnv))
forall thing.
TopLevelFlag
-> [(RecFlag, LHsBinds GhcRn)]
-> [LSig GhcRn]
-> TcM thing
-> TcM ([(RecFlag, LHsBinds GhcTc)], thing)
tcValBinds TopLevelFlag
TopLevel [(RecFlag, LHsBinds GhcRn)]
binds [LSig GhcRn]
sigs TcM (TcGblEnv, TcLclEnv)
forall gbl lcl. TcRnIf gbl lcl (gbl, lcl)
getEnvs
        ; [LTcSpecPrag]
specs <- [LSig GhcRn] -> TcM [LTcSpecPrag]
tcImpPrags [LSig GhcRn]
sigs   -- SPECIALISE prags for imported Ids

        ; [CompleteMatch]
complete_matches <- (TcGblEnv, TcLclEnv)
-> TcRn [CompleteMatch] -> TcRn [CompleteMatch]
forall a. (TcGblEnv, TcLclEnv) -> TcRn a -> TcRn a
restoreEnvs (TcGblEnv
tcg_env, TcLclEnv
tcl_env) (TcRn [CompleteMatch] -> TcRn [CompleteMatch])
-> TcRn [CompleteMatch] -> TcRn [CompleteMatch]
forall a b. (a -> b) -> a -> b
$ [LSig GhcRn] -> TcRn [CompleteMatch]
tcCompleteSigs [LSig GhcRn]
sigs
        ; String -> SDoc -> TcRn ()
traceTc String
"complete_matches" ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))]
-> SDoc
forall a. Outputable a => a -> SDoc
ppr [(RecFlag, LHsBinds GhcRn)]
[(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))]
binds SDoc -> SDoc -> SDoc
$$ [GenLocated SrcSpanAnnA (Sig GhcRn)] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [LSig GhcRn]
[GenLocated SrcSpanAnnA (Sig GhcRn)]
sigs)
        ; String -> SDoc -> TcRn ()
traceTc String
"complete_matches" ([CompleteMatch] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [CompleteMatch]
complete_matches)

        ; let { tcg_env' :: TcGblEnv
tcg_env' = TcGblEnv
tcg_env { tcg_imp_specs :: [LTcSpecPrag]
tcg_imp_specs
                                      = [LTcSpecPrag]
specs [LTcSpecPrag] -> [LTcSpecPrag] -> [LTcSpecPrag]
forall a. [a] -> [a] -> [a]
++ TcGblEnv -> [LTcSpecPrag]
tcg_imp_specs TcGblEnv
tcg_env
                                   , tcg_complete_matches :: [CompleteMatch]
tcg_complete_matches
                                      = [CompleteMatch]
complete_matches
                                          [CompleteMatch] -> [CompleteMatch] -> [CompleteMatch]
forall a. [a] -> [a] -> [a]
++ TcGblEnv -> [CompleteMatch]
tcg_complete_matches TcGblEnv
tcg_env }
                           TcGblEnv -> [LHsBinds GhcTc] -> TcGblEnv
`addTypecheckedBinds` ((RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))
 -> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))
-> [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
-> [Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))]
forall a b. (a -> b) -> [a] -> [b]
map (RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a b. (a, b) -> b
snd [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
binds' }

        ; (TcGblEnv, TcLclEnv) -> TcM (TcGblEnv, TcLclEnv)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (TcGblEnv
tcg_env', TcLclEnv
tcl_env) }
        -- The top level bindings are flattened into a giant
        -- implicitly-mutually-recursive LHsBinds

tcCompleteSigs  :: [LSig GhcRn] -> TcM [CompleteMatch]
tcCompleteSigs :: [LSig GhcRn] -> TcRn [CompleteMatch]
tcCompleteSigs [LSig GhcRn]
sigs =
  let
      doOne :: LSig GhcRn -> TcM (Maybe CompleteMatch)
      -- We don't need to "type-check" COMPLETE signatures anymore; if their
      -- combinations are invalid it will be found so at match sites.
      -- There it is also where we consider if the type of the pattern match is
      -- compatible with the result type constructor 'mb_tc'.
      doOne :: LSig GhcRn -> TcM (Maybe CompleteMatch)
doOne (L SrcSpanAnnA
loc c :: Sig GhcRn
c@(CompleteMatchSig XCompleteMatchSig GhcRn
_ext SourceText
_src_txt (L SrcSpan
_ [GenLocated SrcSpanAnnN Name]
ns) Maybe (LIdP GhcRn)
mb_tc_nm))
        = (CompleteMatch -> Maybe CompleteMatch)
-> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
-> TcM (Maybe CompleteMatch)
forall a b.
(a -> b)
-> IOEnv (Env TcGblEnv TcLclEnv) a
-> IOEnv (Env TcGblEnv TcLclEnv) b
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap CompleteMatch -> Maybe CompleteMatch
forall a. a -> Maybe a
Just (IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
 -> TcM (Maybe CompleteMatch))
-> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
-> TcM (Maybe CompleteMatch)
forall a b. (a -> b) -> a -> b
$ SrcSpanAnnA
-> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
-> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
forall ann a. SrcSpanAnn' ann -> TcRn a -> TcRn a
setSrcSpanA SrcSpanAnnA
loc (IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
 -> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch)
-> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
-> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
forall a b. (a -> b) -> a -> b
$ SDoc
-> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
-> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
forall a. SDoc -> TcM a -> TcM a
addErrCtxt (String -> SDoc
text String
"In" SDoc -> SDoc -> SDoc
<+> Sig GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr Sig GhcRn
c) (IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
 -> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch)
-> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
-> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
forall a b. (a -> b) -> a -> b
$ do
            UniqDSet ConLike
cls   <- [ConLike] -> UniqDSet ConLike
forall a. Uniquable a => [a] -> UniqDSet a
mkUniqDSet ([ConLike] -> UniqDSet ConLike)
-> IOEnv (Env TcGblEnv TcLclEnv) [ConLike]
-> IOEnv (Env TcGblEnv TcLclEnv) (UniqDSet ConLike)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> (GenLocated SrcSpanAnnN Name
 -> IOEnv (Env TcGblEnv TcLclEnv) ConLike)
-> [GenLocated SrcSpanAnnN Name]
-> IOEnv (Env TcGblEnv TcLclEnv) [ConLike]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM ((Name -> IOEnv (Env TcGblEnv TcLclEnv) ConLike)
-> GenLocated SrcSpanAnnN Name
-> IOEnv (Env TcGblEnv TcLclEnv) ConLike
forall a b ann.
(a -> TcM b) -> GenLocated (SrcSpanAnn' ann) a -> TcM b
addLocMA Name -> IOEnv (Env TcGblEnv TcLclEnv) ConLike
tcLookupConLike) [GenLocated SrcSpanAnnN Name]
ns
            Maybe TyCon
mb_tc <- forall (t :: * -> *) (f :: * -> *) a b.
(Traversable t, Applicative f) =>
(a -> f b) -> t a -> f (t b)
traverse @Maybe GenLocated SrcSpanAnnN Name -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcLookupLocatedTyCon Maybe (LIdP GhcRn)
Maybe (GenLocated SrcSpanAnnN Name)
mb_tc_nm
            CompleteMatch -> IOEnv (Env TcGblEnv TcLclEnv) CompleteMatch
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (f :: * -> *) a. Applicative f => a -> f a
pure CompleteMatch { cmConLikes :: UniqDSet ConLike
cmConLikes = UniqDSet ConLike
cls, cmResultTyCon :: Maybe TyCon
cmResultTyCon = Maybe TyCon
mb_tc }
      doOne LSig GhcRn
_ = Maybe CompleteMatch -> TcM (Maybe CompleteMatch)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return Maybe CompleteMatch
forall a. Maybe a
Nothing

  -- For some reason I haven't investigated further, the signatures come in
  -- backwards wrt. declaration order. So we reverse them here, because it makes
  -- a difference for incomplete match suggestions.
  in (GenLocated SrcSpanAnnA (Sig GhcRn) -> TcM (Maybe CompleteMatch))
-> [GenLocated SrcSpanAnnA (Sig GhcRn)] -> TcRn [CompleteMatch]
forall (m :: * -> *) a b.
Applicative m =>
(a -> m (Maybe b)) -> [a] -> m [b]
mapMaybeM LSig GhcRn -> TcM (Maybe CompleteMatch)
GenLocated SrcSpanAnnA (Sig GhcRn) -> TcM (Maybe CompleteMatch)
doOne ([GenLocated SrcSpanAnnA (Sig GhcRn)] -> TcRn [CompleteMatch])
-> [GenLocated SrcSpanAnnA (Sig GhcRn)] -> TcRn [CompleteMatch]
forall a b. (a -> b) -> a -> b
$ [GenLocated SrcSpanAnnA (Sig GhcRn)]
-> [GenLocated SrcSpanAnnA (Sig GhcRn)]
forall a. [a] -> [a]
reverse [LSig GhcRn]
[GenLocated SrcSpanAnnA (Sig GhcRn)]
sigs

tcHsBootSigs :: [(RecFlag, LHsBinds GhcRn)] -> [LSig GhcRn] -> TcM [Id]
-- A hs-boot file has only one BindGroup, and it only has type
-- signatures in it.  The renamer checked all this
tcHsBootSigs :: [(RecFlag, LHsBinds GhcRn)] -> [LSig GhcRn] -> TcM [TcId]
tcHsBootSigs [(RecFlag, LHsBinds GhcRn)]
binds [LSig GhcRn]
sigs
  = do  { Bool -> TcRnMessage -> TcRn ()
checkTc ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))]
-> Bool
forall a. [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [(RecFlag, LHsBinds GhcRn)]
[(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))]
binds) TcRnMessage
TcRnIllegalHsBootFileDecl
        ; (GenLocated SrcSpanAnnA (Sig GhcRn) -> TcM [TcId])
-> [GenLocated SrcSpanAnnA (Sig GhcRn)] -> TcM [TcId]
forall (m :: * -> *) a b. Monad m => (a -> m [b]) -> [a] -> m [b]
concatMapM ((Sig GhcRn -> TcM [TcId])
-> GenLocated SrcSpanAnnA (Sig GhcRn) -> TcM [TcId]
forall a b ann.
(a -> TcM b) -> GenLocated (SrcSpanAnn' ann) a -> TcM b
addLocMA Sig GhcRn -> TcM [TcId]
tc_boot_sig) ((GenLocated SrcSpanAnnA (Sig GhcRn) -> Bool)
-> [GenLocated SrcSpanAnnA (Sig GhcRn)]
-> [GenLocated SrcSpanAnnA (Sig GhcRn)]
forall a. (a -> Bool) -> [a] -> [a]
filter LSig GhcRn -> Bool
GenLocated SrcSpanAnnA (Sig GhcRn) -> Bool
forall p. UnXRec p => LSig p -> Bool
isTypeLSig [LSig GhcRn]
[GenLocated SrcSpanAnnA (Sig GhcRn)]
sigs) }
  where
    tc_boot_sig :: Sig GhcRn -> TcM [TcId]
tc_boot_sig (TypeSig XTypeSig GhcRn
_ [LIdP GhcRn]
lnames LHsSigWcType GhcRn
hs_ty) = (GenLocated SrcSpanAnnN Name -> IOEnv (Env TcGblEnv TcLclEnv) TcId)
-> [GenLocated SrcSpanAnnN Name] -> TcM [TcId]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM GenLocated SrcSpanAnnN Name -> IOEnv (Env TcGblEnv TcLclEnv) TcId
f [LIdP GhcRn]
[GenLocated SrcSpanAnnN Name]
lnames
      where
        f :: GenLocated SrcSpanAnnN Name -> IOEnv (Env TcGblEnv TcLclEnv) TcId
f (L SrcSpanAnnN
_ Name
name)
          = do { Kind
sigma_ty <- UserTypeCtxt -> LHsSigWcType GhcRn -> TcM Kind
tcHsSigWcType (Name -> ReportRedundantConstraints -> UserTypeCtxt
FunSigCtxt Name
name ReportRedundantConstraints
NoRRC) LHsSigWcType GhcRn
hs_ty
               ; TcId -> IOEnv (Env TcGblEnv TcLclEnv) TcId
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (Name -> Kind -> TcId
mkVanillaGlobal Name
name Kind
sigma_ty) }
        -- Notice that we make GlobalIds, not LocalIds
    tc_boot_sig Sig GhcRn
s = String -> SDoc -> TcM [TcId]
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"tcHsBootSigs/tc_boot_sig" (Sig GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr Sig GhcRn
s)

------------------------
tcLocalBinds :: HsLocalBinds GhcRn -> TcM thing
             -> TcM (HsLocalBinds GhcTc, thing)

tcLocalBinds :: forall thing.
HsLocalBinds GhcRn -> TcM thing -> TcM (HsLocalBinds GhcTc, thing)
tcLocalBinds (EmptyLocalBinds XEmptyLocalBinds GhcRn GhcRn
x) TcM thing
thing_inside
  = do  { thing
thing <- TcM thing
thing_inside
        ; (HsLocalBinds GhcTc, thing) -> TcM (HsLocalBinds GhcTc, thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (XEmptyLocalBinds GhcTc GhcTc -> HsLocalBinds GhcTc
forall idL idR. XEmptyLocalBinds idL idR -> HsLocalBindsLR idL idR
EmptyLocalBinds XEmptyLocalBinds GhcRn GhcRn
XEmptyLocalBinds GhcTc GhcTc
x, thing
thing) }

tcLocalBinds (HsValBinds XHsValBinds GhcRn GhcRn
x (XValBindsLR (NValBinds [(RecFlag, LHsBinds GhcRn)]
binds [LSig GhcRn]
sigs))) TcM thing
thing_inside
  = do  { ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
binds', thing
thing) <- TopLevelFlag
-> [(RecFlag, LHsBinds GhcRn)]
-> [LSig GhcRn]
-> TcM thing
-> TcM ([(RecFlag, LHsBinds GhcTc)], thing)
forall thing.
TopLevelFlag
-> [(RecFlag, LHsBinds GhcRn)]
-> [LSig GhcRn]
-> TcM thing
-> TcM ([(RecFlag, LHsBinds GhcTc)], thing)
tcValBinds TopLevelFlag
NotTopLevel [(RecFlag, LHsBinds GhcRn)]
binds [LSig GhcRn]
sigs TcM thing
thing_inside
        ; (HsLocalBinds GhcTc, thing) -> TcM (HsLocalBinds GhcTc, thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (XHsValBinds GhcTc GhcTc
-> HsValBindsLR GhcTc GhcTc -> HsLocalBinds GhcTc
forall idL idR.
XHsValBinds idL idR
-> HsValBindsLR idL idR -> HsLocalBindsLR idL idR
HsValBinds XHsValBinds GhcRn GhcRn
XHsValBinds GhcTc GhcTc
x (XXValBindsLR GhcTc GhcTc -> HsValBindsLR GhcTc GhcTc
forall idL idR. XXValBindsLR idL idR -> HsValBindsLR idL idR
XValBindsLR ([(RecFlag, LHsBinds GhcTc)] -> [LSig GhcRn] -> NHsValBindsLR GhcTc
forall idL.
[(RecFlag, LHsBinds idL)] -> [LSig GhcRn] -> NHsValBindsLR idL
NValBinds [(RecFlag, LHsBinds GhcTc)]
[(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
binds' [LSig GhcRn]
sigs)), thing
thing) }
tcLocalBinds (HsValBinds XHsValBinds GhcRn GhcRn
_ (ValBinds {})) TcM thing
_ = String -> TcM (HsLocalBinds GhcTc, thing)
forall a. String -> a
panic String
"tcLocalBinds"

tcLocalBinds (HsIPBinds XHsIPBinds GhcRn GhcRn
x (IPBinds XIPBinds GhcRn
_ [LIPBind GhcRn]
ip_binds)) TcM thing
thing_inside
  = do  { Class
ipClass <- Name -> TcM Class
tcLookupClass Name
ipClassName
        ; ([TcId]
given_ips, [GenLocated SrcSpanAnnA (IPBind GhcTc)]
ip_binds') <-
            (GenLocated SrcSpanAnnA (IPBind GhcRn)
 -> IOEnv
      (Env TcGblEnv TcLclEnv)
      (TcId, GenLocated SrcSpanAnnA (IPBind GhcTc)))
-> [GenLocated SrcSpanAnnA (IPBind GhcRn)]
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ([TcId], [GenLocated SrcSpanAnnA (IPBind GhcTc)])
forall (m :: * -> *) a b c.
Applicative m =>
(a -> m (b, c)) -> [a] -> m ([b], [c])
mapAndUnzipM ((IPBind GhcRn -> TcM (TcId, IPBind GhcTc))
-> GenLocated SrcSpanAnnA (IPBind GhcRn)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (TcId, GenLocated SrcSpanAnnA (IPBind GhcTc))
forall a b c ann.
(a -> TcM (b, c))
-> GenLocated (SrcSpanAnn' ann) a
-> TcM (b, GenLocated (SrcSpanAnn' ann) c)
wrapLocSndMA (Class -> IPBind GhcRn -> TcM (TcId, IPBind GhcTc)
tc_ip_bind Class
ipClass)) [LIPBind GhcRn]
[GenLocated SrcSpanAnnA (IPBind GhcRn)]
ip_binds

        -- Add all the IP bindings as givens for the body of the 'let'
        ; (TcEvBinds
ev_binds, thing
result) <- SkolemInfoAnon
-> [TcId] -> [TcId] -> TcM thing -> TcM (TcEvBinds, thing)
forall result.
SkolemInfoAnon
-> [TcId] -> [TcId] -> TcM result -> TcM (TcEvBinds, result)
checkConstraints ([HsIPName] -> SkolemInfoAnon
IPSkol [HsIPName]
ips)
                                  [] [TcId]
given_ips TcM thing
thing_inside

        ; (HsLocalBinds GhcTc, thing) -> TcM (HsLocalBinds GhcTc, thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (XHsIPBinds GhcTc GhcTc -> HsIPBinds GhcTc -> HsLocalBinds GhcTc
forall idL idR.
XHsIPBinds idL idR -> HsIPBinds idR -> HsLocalBindsLR idL idR
HsIPBinds XHsIPBinds GhcRn GhcRn
XHsIPBinds GhcTc GhcTc
x (XIPBinds GhcTc -> [LIPBind GhcTc] -> HsIPBinds GhcTc
forall id. XIPBinds id -> [LIPBind id] -> HsIPBinds id
IPBinds XIPBinds GhcTc
TcEvBinds
ev_binds [LIPBind GhcTc]
[GenLocated SrcSpanAnnA (IPBind GhcTc)]
ip_binds') , thing
result) }
  where
    ips :: [HsIPName]
ips = [HsIPName
ip | (L SrcSpanAnnA
_ (IPBind XCIPBind GhcRn
_ (L SrcAnn NoEpAnns
_ HsIPName
ip) LHsExpr GhcRn
_)) <- [LIPBind GhcRn]
[GenLocated SrcSpanAnnA (IPBind GhcRn)]
ip_binds]

        -- I wonder if we should do these one at a time
        -- Consider     ?x = 4
        --              ?y = ?x + 1
    tc_ip_bind :: Class -> IPBind GhcRn -> TcM (DictId, IPBind GhcTc)
    tc_ip_bind :: Class -> IPBind GhcRn -> TcM (TcId, IPBind GhcTc)
tc_ip_bind Class
ipClass (IPBind XCIPBind GhcRn
_ l_name :: XRec GhcRn HsIPName
l_name@(L SrcAnn NoEpAnns
_ HsIPName
ip) LHsExpr GhcRn
expr)
       = do { Kind
ty <- TcM Kind
newOpenFlexiTyVarTy
            ; let p :: Kind
p = FastString -> Kind
mkStrLitTy (FastString -> Kind) -> FastString -> Kind
forall a b. (a -> b) -> a -> b
$ HsIPName -> FastString
hsIPNameFS HsIPName
ip
            ; TcId
ip_id <- Class -> TcThetaType -> IOEnv (Env TcGblEnv TcLclEnv) TcId
newDict Class
ipClass [ Kind
p, Kind
ty ]
            ; GenLocated SrcSpanAnnA (HsExpr GhcTc)
expr' <- LHsExpr GhcRn -> Kind -> TcM (LHsExpr GhcTc)
tcCheckMonoExpr LHsExpr GhcRn
expr Kind
ty
            ; let d :: GenLocated SrcSpanAnnA (HsExpr GhcTc)
d = (HsExpr GhcTc -> HsExpr GhcTc)
-> GenLocated SrcSpanAnnA (HsExpr GhcTc)
-> GenLocated SrcSpanAnnA (HsExpr GhcTc)
forall a b l. (a -> b) -> GenLocated l a -> GenLocated l b
mapLoc (Class -> Kind -> Kind -> HsExpr GhcTc -> HsExpr GhcTc
toDict Class
ipClass Kind
p Kind
ty) GenLocated SrcSpanAnnA (HsExpr GhcTc)
expr'
            ; (TcId, IPBind GhcTc) -> TcM (TcId, IPBind GhcTc)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (TcId
ip_id, (XCIPBind GhcTc
-> XRec GhcTc HsIPName -> LHsExpr GhcTc -> IPBind GhcTc
forall id.
XCIPBind id -> XRec id HsIPName -> LHsExpr id -> IPBind id
IPBind XCIPBind GhcTc
TcId
ip_id XRec GhcRn HsIPName
XRec GhcTc HsIPName
l_name LHsExpr GhcTc
GenLocated SrcSpanAnnA (HsExpr GhcTc)
d)) }

    -- Coerces a `t` into a dictionary for `IP "x" t`.
    -- co : t -> IP "x" t
    toDict :: Class  -- IP class
           -> Type   -- type-level string for name of IP
           -> Type   -- type of IP
           -> HsExpr GhcTc   -- def'n of IP variable
           -> HsExpr GhcTc   -- dictionary for IP
    toDict :: Class -> Kind -> Kind -> HsExpr GhcTc -> HsExpr GhcTc
toDict Class
ipClass Kind
x Kind
ty = HsWrapper -> HsExpr GhcTc -> HsExpr GhcTc
mkHsWrap (HsWrapper -> HsExpr GhcTc -> HsExpr GhcTc)
-> HsWrapper -> HsExpr GhcTc -> HsExpr GhcTc
forall a b. (a -> b) -> a -> b
$ TcCoercionR -> HsWrapper
mkWpCastR (TcCoercionR -> HsWrapper) -> TcCoercionR -> HsWrapper
forall a b. (a -> b) -> a -> b
$
                          Kind -> TcCoercionR
wrapIP (Kind -> TcCoercionR) -> Kind -> TcCoercionR
forall a b. (a -> b) -> a -> b
$ Class -> TcThetaType -> Kind
mkClassPred Class
ipClass [Kind
x,Kind
ty]

tcValBinds :: TopLevelFlag
           -> [(RecFlag, LHsBinds GhcRn)] -> [LSig GhcRn]
           -> TcM thing
           -> TcM ([(RecFlag, LHsBinds GhcTc)], thing)

tcValBinds :: forall thing.
TopLevelFlag
-> [(RecFlag, LHsBinds GhcRn)]
-> [LSig GhcRn]
-> TcM thing
-> TcM ([(RecFlag, LHsBinds GhcTc)], thing)
tcValBinds TopLevelFlag
top_lvl [(RecFlag, LHsBinds GhcRn)]
binds [LSig GhcRn]
sigs TcM thing
thing_inside
  = do  {   -- Typecheck the signatures
            -- It's easier to do so now, once for all the SCCs together
            -- because a single signature  f,g :: <type>
            -- might relate to more than one SCC
          ([TcId]
poly_ids, TcSigFun
sig_fn) <- [PatSynBind GhcRn GhcRn]
-> TcM ([TcId], TcSigFun) -> TcM ([TcId], TcSigFun)
forall a. [PatSynBind GhcRn GhcRn] -> TcM a -> TcM a
tcAddPatSynPlaceholders [PatSynBind GhcRn GhcRn]
patsyns (TcM ([TcId], TcSigFun) -> TcM ([TcId], TcSigFun))
-> TcM ([TcId], TcSigFun) -> TcM ([TcId], TcSigFun)
forall a b. (a -> b) -> a -> b
$
                                [LSig GhcRn] -> TcM ([TcId], TcSigFun)
tcTySigs [LSig GhcRn]
sigs

        -- Extend the envt right away with all the Ids
        --   declared with complete type signatures
        -- Do not extend the TcBinderStack; instead
        --   we extend it on a per-rhs basis in tcExtendForRhs
        --   See Note [Relevant bindings and the binder stack]
        --
        -- For the moment, let bindings and top-level bindings introduce
        -- only unrestricted variables.
        ; TopLevelFlag
-> [TcId]
-> TcM
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
-> TcM
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
forall a. TopLevelFlag -> [TcId] -> TcM a -> TcM a
tcExtendSigIds TopLevelFlag
top_lvl [TcId]
poly_ids (TcM
   ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
    thing)
 -> TcM
      ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
       thing))
-> TcM
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
-> TcM
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
forall a b. (a -> b) -> a -> b
$
     do { ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
binds', ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
extra_binds', thing
thing))
              <- TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> [(RecFlag, LHsBinds GhcRn)]
-> TcM
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
-> TcM
     ([(RecFlag, LHsBinds GhcTc)],
      ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
       thing))
forall thing.
TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> [(RecFlag, LHsBinds GhcRn)]
-> TcM thing
-> TcM ([(RecFlag, LHsBinds GhcTc)], thing)
tcBindGroups TopLevelFlag
top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn [(RecFlag, LHsBinds GhcRn)]
binds (TcM
   ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
    thing)
 -> TcM
      ([(RecFlag, LHsBinds GhcTc)],
       ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
        thing)))
-> TcM
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
-> TcM
     ([(RecFlag, LHsBinds GhcTc)],
      ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
       thing))
forall a b. (a -> b) -> a -> b
$
                 do { thing
thing <- TcM thing
thing_inside
                       -- See Note [Pattern synonym builders don't yield dependencies]
                       --     in GHC.Rename.Bind
                    ; [Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))]
patsyn_builders <- (PatSynBind GhcRn GhcRn
 -> IOEnv
      (Env TcGblEnv TcLclEnv)
      (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))))
-> [PatSynBind GhcRn GhcRn]
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     [Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM (TcPragEnv -> PatSynBind GhcRn GhcRn -> TcM (LHsBinds GhcTc)
tcPatSynBuilderBind TcPragEnv
prag_fn) [PatSynBind GhcRn GhcRn]
patsyns
                    ; let extra_binds :: [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
extra_binds = [ (RecFlag
NonRecursive, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
builder)
                                        | Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
builder <- [Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))]
patsyn_builders ]
                    ; ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
 thing)
-> TcM
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
extra_binds, thing
thing) }
        ; ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
 thing)
-> TcM
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
binds' [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
-> [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
-> [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
forall a. [a] -> [a] -> [a]
++ [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
extra_binds', thing
thing) }}
  where
    patsyns :: [PatSynBind GhcRn GhcRn]
patsyns = [(RecFlag, LHsBinds GhcRn)] -> [PatSynBind GhcRn GhcRn]
forall id.
UnXRec id =>
[(RecFlag, LHsBinds id)] -> [PatSynBind id id]
getPatSynBinds [(RecFlag, LHsBinds GhcRn)]
binds
    prag_fn :: TcPragEnv
prag_fn = [LSig GhcRn] -> LHsBinds GhcRn -> TcPragEnv
mkPragEnv [LSig GhcRn]
sigs (((RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))
 -> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
 -> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
-> [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))]
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
forall a b. (a -> b -> b) -> b -> [a] -> b
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
forall a. Bag a -> Bag a -> Bag a
unionBags (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
 -> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
 -> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))
-> ((RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))
    -> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))
-> (RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
forall a b. (a, b) -> b
snd) Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
forall a. Bag a
emptyBag [(RecFlag, LHsBinds GhcRn)]
[(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))]
binds)

------------------------
tcBindGroups :: TopLevelFlag -> TcSigFun -> TcPragEnv
             -> [(RecFlag, LHsBinds GhcRn)] -> TcM thing
             -> TcM ([(RecFlag, LHsBinds GhcTc)], thing)
-- Typecheck a whole lot of value bindings,
-- one strongly-connected component at a time
-- Here a "strongly connected component" has the straightforward
-- meaning of a group of bindings that mention each other,
-- ignoring type signatures (that part comes later)

tcBindGroups :: forall thing.
TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> [(RecFlag, LHsBinds GhcRn)]
-> TcM thing
-> TcM ([(RecFlag, LHsBinds GhcTc)], thing)
tcBindGroups TopLevelFlag
_ TcSigFun
_ TcPragEnv
_ [] TcM thing
thing_inside
  = do  { thing
thing <- TcM thing
thing_inside
        ; ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
 thing)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ([], thing
thing) }

tcBindGroups TopLevelFlag
top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn ((RecFlag, LHsBinds GhcRn)
group : [(RecFlag, LHsBinds GhcRn)]
groups) TcM thing
thing_inside
  = do  { -- See Note [Closed binder groups]
          TcTypeEnv
type_env <- TcM TcTypeEnv
getLclTypeEnv
        ; let closed :: IsGroupClosed
closed = TcTypeEnv -> LHsBinds GhcRn -> IsGroupClosed
isClosedBndrGroup TcTypeEnv
type_env ((RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
forall a b. (a, b) -> b
snd (RecFlag, LHsBinds GhcRn)
(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)))
group)
        ; ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
group', ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
groups', thing
thing))
                <- TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> (RecFlag, LHsBinds GhcRn)
-> IsGroupClosed
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
-> TcM
     ([(RecFlag, LHsBinds GhcTc)],
      ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
       thing))
forall thing.
TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> (RecFlag, LHsBinds GhcRn)
-> IsGroupClosed
-> TcM thing
-> TcM ([(RecFlag, LHsBinds GhcTc)], thing)
tc_group TopLevelFlag
top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn (RecFlag, LHsBinds GhcRn)
group IsGroupClosed
closed (IOEnv
   (Env TcGblEnv TcLclEnv)
   ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
    thing)
 -> TcM
      ([(RecFlag, LHsBinds GhcTc)],
       ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
        thing)))
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
-> TcM
     ([(RecFlag, LHsBinds GhcTc)],
      ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
       thing))
forall a b. (a -> b) -> a -> b
$
                   TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> [(RecFlag, LHsBinds GhcRn)]
-> TcM thing
-> TcM ([(RecFlag, LHsBinds GhcTc)], thing)
forall thing.
TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> [(RecFlag, LHsBinds GhcRn)]
-> TcM thing
-> TcM ([(RecFlag, LHsBinds GhcTc)], thing)
tcBindGroups TopLevelFlag
top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn [(RecFlag, LHsBinds GhcRn)]
groups TcM thing
thing_inside
        ; ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
 thing)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
group' [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
-> [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
-> [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
forall a. [a] -> [a] -> [a]
++ [(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))]
groups', thing
thing) }

-- Note [Closed binder groups]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
--  A mutually recursive group is "closed" if all of the free variables of
--  the bindings are closed. For example
--
-- >  h = \x -> let f = ...g...
-- >                g = ....f...x...
-- >             in ...
--
-- Here @g@ is not closed because it mentions @x@; and hence neither is @f@
-- closed.
--
-- So we need to compute closed-ness on each strongly connected components,
-- before we sub-divide it based on what type signatures it has.
--

------------------------
tc_group :: forall thing.
            TopLevelFlag -> TcSigFun -> TcPragEnv
         -> (RecFlag, LHsBinds GhcRn) -> IsGroupClosed -> TcM thing
         -> TcM ([(RecFlag, LHsBinds GhcTc)], thing)

-- Typecheck one strongly-connected component of the original program.
-- We get a list of groups back, because there may
-- be specialisations etc as well

tc_group :: forall thing.
TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> (RecFlag, LHsBinds GhcRn)
-> IsGroupClosed
-> TcM thing
-> TcM ([(RecFlag, LHsBinds GhcTc)], thing)
tc_group TopLevelFlag
top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn (RecFlag
NonRecursive, LHsBinds GhcRn
binds) IsGroupClosed
closed TcM thing
thing_inside
        -- A single non-recursive binding
        -- We want to keep non-recursive things non-recursive
        -- so that we desugar unlifted bindings correctly
  = do { let bind :: GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind = case Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
-> [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
forall a. Bag a -> [a]
bagToList LHsBinds GhcRn
Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
binds of
                 [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind] -> GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind
                 []     -> String -> GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
forall a. String -> a
panic String
"tc_group: empty list of binds"
                 [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
_      -> String -> GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
forall a. String -> a
panic String
"tc_group: NonRecursive binds is not a singleton bag"
       ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
bind', thing
thing) <- TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> LHsBind GhcRn
-> IsGroupClosed
-> TcM thing
-> TcM (LHsBinds GhcTc, thing)
forall thing.
TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> LHsBind GhcRn
-> IsGroupClosed
-> TcM thing
-> TcM (LHsBinds GhcTc, thing)
tc_single TopLevelFlag
top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn LHsBind GhcRn
GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind IsGroupClosed
closed
                                     TcM thing
thing_inside
       ; ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
 thing)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ( [(RecFlag
NonRecursive, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
bind')], thing
thing) }

tc_group TopLevelFlag
top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn (RecFlag
Recursive, LHsBinds GhcRn
binds) IsGroupClosed
closed TcM thing
thing_inside
  =     -- To maximise polymorphism, we do a new
        -- strongly-connected-component analysis, this time omitting
        -- any references to variables with type signatures.
        -- (This used to be optional, but isn't now.)
        -- See Note [Polymorphic recursion] in "GHC.Hs.Binds".
    do  { String -> SDoc -> TcRn ()
traceTc String
"tc_group rec" (LHsBinds GhcRn -> SDoc
forall (idL :: Pass) (idR :: Pass).
(OutputableBndrId idL, OutputableBndrId idR) =>
LHsBindsLR (GhcPass idL) (GhcPass idR) -> SDoc
pprLHsBinds LHsBinds GhcRn
binds)
        ; Maybe (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
-> (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn) -> TcRn ())
-> TcRn ()
forall (m :: * -> *) a. Monad m => Maybe a -> (a -> m ()) -> m ()
whenIsJust Maybe (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
mbFirstPatSyn ((GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn) -> TcRn ())
 -> TcRn ())
-> (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn) -> TcRn ())
-> TcRn ()
forall a b. (a -> b) -> a -> b
$ \GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
lpat_syn ->
            SrcSpan -> LHsBinds GhcRn -> TcRn ()
forall a. SrcSpan -> LHsBinds GhcRn -> TcM a
recursivePatSynErr (SrcSpanAnnA -> SrcSpan
forall a. SrcSpanAnn' a -> SrcSpan
locA (SrcSpanAnnA -> SrcSpan) -> SrcSpanAnnA -> SrcSpan
forall a b. (a -> b) -> a -> b
$ GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn) -> SrcSpanAnnA
forall l e. GenLocated l e -> l
getLoc GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
lpat_syn) LHsBinds GhcRn
binds
        ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds1, thing
thing) <- [SCC (LHsBind GhcRn)] -> TcM (LHsBinds GhcTc, thing)
go [SCC (LHsBind GhcRn)]
sccs
        ; ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
 thing)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ([(RecFlag, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))],
      thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ([(RecFlag
Recursive, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds1)], thing
thing) }
                -- Rec them all together
  where
    mbFirstPatSyn :: Maybe (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
mbFirstPatSyn = (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn) -> Bool)
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
-> Maybe (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Maybe a
find (HsBindLR GhcRn GhcRn -> Bool
forall {idL} {idR}. HsBindLR idL idR -> Bool
isPatSyn (HsBindLR GhcRn GhcRn -> Bool)
-> (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
    -> HsBindLR GhcRn GhcRn)
-> GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
-> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
-> HsBindLR GhcRn GhcRn
forall l e. GenLocated l e -> e
unLoc) LHsBinds GhcRn
Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
binds
    isPatSyn :: HsBindLR idL idR -> Bool
isPatSyn PatSynBind{} = Bool
True
    isPatSyn HsBindLR idL idR
_ = Bool
False

    sccs :: [SCC (LHsBind GhcRn)]
    sccs :: [SCC (LHsBind GhcRn)]
sccs = [Node BKey (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))]
-> [SCC (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))]
forall key payload.
Uniquable key =>
[Node key payload] -> [SCC payload]
stronglyConnCompFromEdgedVerticesUniq (TcSigFun -> LHsBinds GhcRn -> [Node BKey (LHsBind GhcRn)]
mkEdges TcSigFun
sig_fn LHsBinds GhcRn
binds)

    go :: [SCC (LHsBind GhcRn)] -> TcM (LHsBinds GhcTc, thing)
    go :: [SCC (LHsBind GhcRn)] -> TcM (LHsBinds GhcTc, thing)
go (SCC (LHsBind GhcRn)
scc:[SCC (LHsBind GhcRn)]
sccs) = do  { (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds1, [TcId]
ids1) <- SCC (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
-> TcM (LHsBinds GhcTc, [TcId])
tc_scc SCC (LHsBind GhcRn)
SCC (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
scc
                         -- recursive bindings must be unrestricted
                         -- (the ids added to the environment here are the name of the recursive definitions).
                        ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds2, thing
thing) <- TopLevelFlag
-> TcSigFun
-> IsGroupClosed
-> [TcId]
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), thing)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), thing)
forall a.
TopLevelFlag
-> TcSigFun -> IsGroupClosed -> [TcId] -> TcM a -> TcM a
tcExtendLetEnv TopLevelFlag
top_lvl TcSigFun
sig_fn IsGroupClosed
closed [TcId]
ids1
                                                            ([SCC (LHsBind GhcRn)] -> TcM (LHsBinds GhcTc, thing)
go [SCC (LHsBind GhcRn)]
sccs)
                        ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), thing)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds1 Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a. Bag a -> Bag a -> Bag a
`unionBags` Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds2, thing
thing) }
    go []         = do  { thing
thing <- TcM thing
thing_inside; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), thing)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a. Bag a
emptyBag, thing
thing) }

    tc_scc :: SCC (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
-> TcM (LHsBinds GhcTc, [TcId])
tc_scc (AcyclicSCC GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind) = RecFlag
-> [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
-> TcM (LHsBinds GhcTc, [TcId])
tc_sub_group RecFlag
NonRecursive [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind]
    tc_scc (CyclicSCC [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
binds) = RecFlag
-> [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
-> TcM (LHsBinds GhcTc, [TcId])
tc_sub_group RecFlag
Recursive    [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
binds

    tc_sub_group :: RecFlag
-> [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
-> TcM (LHsBinds GhcTc, [TcId])
tc_sub_group RecFlag
rec_tc [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
binds = TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> RecFlag
-> RecFlag
-> IsGroupClosed
-> [LHsBind GhcRn]
-> TcM (LHsBinds GhcTc, [TcId])
tcPolyBinds TopLevelFlag
top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn
                                            RecFlag
Recursive RecFlag
rec_tc IsGroupClosed
closed [LHsBind GhcRn]
[GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
binds

recursivePatSynErr
  :: SrcSpan -- ^ The location of the first pattern synonym binding
             --   (for error reporting)
  -> LHsBinds GhcRn
  -> TcM a
recursivePatSynErr :: forall a. SrcSpan -> LHsBinds GhcRn -> TcM a
recursivePatSynErr SrcSpan
loc LHsBinds GhcRn
binds
  = SrcSpan -> TcRnMessage -> TcRn a
forall a. SrcSpan -> TcRnMessage -> TcRn a
failAt SrcSpan
loc (TcRnMessage -> TcRn a) -> TcRnMessage -> TcRn a
forall a b. (a -> b) -> a -> b
$ LHsBinds GhcRn -> TcRnMessage
TcRnRecursivePatternSynonym LHsBinds GhcRn
binds

tc_single :: forall thing.
            TopLevelFlag -> TcSigFun -> TcPragEnv
          -> LHsBind GhcRn -> IsGroupClosed -> TcM thing
          -> TcM (LHsBinds GhcTc, thing)
tc_single :: forall thing.
TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> LHsBind GhcRn
-> IsGroupClosed
-> TcM thing
-> TcM (LHsBinds GhcTc, thing)
tc_single TopLevelFlag
_top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn
          (L SrcSpanAnnA
loc (PatSynBind XPatSynBind GhcRn GhcRn
_ PatSynBind GhcRn GhcRn
psb))
          IsGroupClosed
_ TcM thing
thing_inside
  = do { (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
aux_binds, TcGblEnv
tcg_env) <- LocatedA (PatSynBind GhcRn GhcRn)
-> TcSigFun -> TcPragEnv -> TcM (LHsBinds GhcTc, TcGblEnv)
tcPatSynDecl (SrcSpanAnnA
-> PatSynBind GhcRn GhcRn -> LocatedA (PatSynBind GhcRn GhcRn)
forall l e. l -> e -> GenLocated l e
L SrcSpanAnnA
loc PatSynBind GhcRn GhcRn
psb) TcSigFun
sig_fn TcPragEnv
prag_fn
       ; thing
thing <- TcGblEnv -> TcM thing -> TcM thing
forall gbl' lcl a gbl.
gbl' -> TcRnIf gbl' lcl a -> TcRnIf gbl lcl a
setGblEnv TcGblEnv
tcg_env TcM thing
thing_inside
       ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), thing)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
aux_binds, thing
thing)
       }

tc_single TopLevelFlag
top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn LHsBind GhcRn
lbind IsGroupClosed
closed TcM thing
thing_inside
  = do { (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds1, [TcId]
ids) <- TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> RecFlag
-> RecFlag
-> IsGroupClosed
-> [LHsBind GhcRn]
-> TcM (LHsBinds GhcTc, [TcId])
tcPolyBinds TopLevelFlag
top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn
                                      RecFlag
NonRecursive RecFlag
NonRecursive
                                      IsGroupClosed
closed
                                      [LHsBind GhcRn
lbind]
         -- since we are defining a non-recursive binding, it is not necessary here
         -- to define an unrestricted binding. But we do so until toplevel linear bindings are supported.
       ; thing
thing <- TopLevelFlag
-> TcSigFun -> IsGroupClosed -> [TcId] -> TcM thing -> TcM thing
forall a.
TopLevelFlag
-> TcSigFun -> IsGroupClosed -> [TcId] -> TcM a -> TcM a
tcExtendLetEnv TopLevelFlag
top_lvl TcSigFun
sig_fn IsGroupClosed
closed [TcId]
ids TcM thing
thing_inside
       ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), thing)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), thing)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds1, thing
thing) }

------------------------
type BKey = Int -- Just number off the bindings

mkEdges :: TcSigFun -> LHsBinds GhcRn -> [Node BKey (LHsBind GhcRn)]
-- See Note [Polymorphic recursion] in "GHC.Hs.Binds".
mkEdges :: TcSigFun -> LHsBinds GhcRn -> [Node BKey (LHsBind GhcRn)]
mkEdges TcSigFun
sig_fn LHsBinds GhcRn
binds
  = [ GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
-> BKey
-> [BKey]
-> Node BKey (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
forall key payload. payload -> key -> [key] -> Node key payload
DigraphNode GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind BKey
key [BKey
key | Name
n <- UniqSet Name -> [Name]
forall elt. UniqSet elt -> [elt]
nonDetEltsUniqSet (HsBindLR GhcRn GhcRn -> XFunBind GhcRn GhcRn
forall {idL} {idR}.
(XFunBind idL idR ~ UniqSet Name,
 XPatBind idL idR ~ UniqSet Name) =>
HsBindLR idL idR -> XFunBind idL idR
bind_fvs (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
-> HsBindLR GhcRn GhcRn
forall l e. GenLocated l e -> e
unLoc GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind)),
                         Just BKey
key <- [NameEnv BKey -> Name -> Maybe BKey
forall a. NameEnv a -> Name -> Maybe a
lookupNameEnv NameEnv BKey
key_map Name
n], Name -> Bool
no_sig Name
n ]
    | (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind, BKey
key) <- [(GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn), BKey)]
keyd_binds
    ]
    -- It's OK to use nonDetEltsUFM here as stronglyConnCompFromEdgedVertices
    -- is still deterministic even if the edges are in nondeterministic order
    -- as explained in Note [Deterministic SCC] in GHC.Data.Graph.Directed.
  where
    bind_fvs :: HsBindLR idL idR -> XFunBind idL idR
bind_fvs (FunBind { fun_ext :: forall idL idR. HsBindLR idL idR -> XFunBind idL idR
fun_ext = XFunBind idL idR
fvs }) = XFunBind idL idR
fvs
    bind_fvs (PatBind { pat_ext :: forall idL idR. HsBindLR idL idR -> XPatBind idL idR
pat_ext = XPatBind idL idR
fvs }) = XPatBind idL idR
XFunBind idL idR
fvs
    bind_fvs HsBindLR idL idR
_                           = XFunBind idL idR
UniqSet Name
emptyNameSet

    no_sig :: Name -> Bool
    no_sig :: Name -> Bool
no_sig Name
n = Bool -> Bool
not (TcSigFun -> Name -> Bool
hasCompleteSig TcSigFun
sig_fn Name
n)

    keyd_binds :: [(GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn), BKey)]
keyd_binds = Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
-> [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
forall a. Bag a -> [a]
bagToList LHsBinds GhcRn
Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
binds [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
-> [BKey]
-> [(GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn), BKey)]
forall a b. [a] -> [b] -> [(a, b)]
`zip` [BKey
0::BKey ..]

    key_map :: NameEnv BKey     -- Which binding it comes from
    key_map :: NameEnv BKey
key_map = [(Name, BKey)] -> NameEnv BKey
forall a. [(Name, a)] -> NameEnv a
mkNameEnv [(Name
bndr, BKey
key) | (L SrcSpanAnnA
_ HsBindLR GhcRn GhcRn
bind, BKey
key) <- [(GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn), BKey)]
keyd_binds
                                     , Name
bndr <- CollectFlag GhcRn -> HsBindLR GhcRn GhcRn -> [IdP GhcRn]
forall p idR.
CollectPass p =>
CollectFlag p -> HsBindLR p idR -> [IdP p]
collectHsBindBinders CollectFlag GhcRn
forall p. CollectFlag p
CollNoDictBinders HsBindLR GhcRn GhcRn
bind ]

------------------------
tcPolyBinds :: TopLevelFlag -> TcSigFun -> TcPragEnv
            -> RecFlag         -- Whether the group is really recursive
            -> RecFlag         -- Whether it's recursive after breaking
                               -- dependencies based on type signatures
            -> IsGroupClosed   -- Whether the group is closed
            -> [LHsBind GhcRn]  -- None are PatSynBind
            -> TcM (LHsBinds GhcTc, [TcId])

-- Typechecks a single bunch of values bindings all together,
-- and generalises them.  The bunch may be only part of a recursive
-- group, because we use type signatures to maximise polymorphism
--
-- Returns a list because the input may be a single non-recursive binding,
-- in which case the dependency order of the resulting bindings is
-- important.
--
-- Knows nothing about the scope of the bindings
-- None of the bindings are pattern synonyms

tcPolyBinds :: TopLevelFlag
-> TcSigFun
-> TcPragEnv
-> RecFlag
-> RecFlag
-> IsGroupClosed
-> [LHsBind GhcRn]
-> TcM (LHsBinds GhcTc, [TcId])
tcPolyBinds TopLevelFlag
top_lvl TcSigFun
sig_fn TcPragEnv
prag_fn RecFlag
rec_group RecFlag
rec_tc IsGroupClosed
closed [LHsBind GhcRn]
bind_list
  = SrcSpan
-> TcM (LHsBinds GhcTc, [TcId]) -> TcM (LHsBinds GhcTc, [TcId])
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
loc                              (TcM (LHsBinds GhcTc, [TcId]) -> TcM (LHsBinds GhcTc, [TcId]))
-> TcM (LHsBinds GhcTc, [TcId]) -> TcM (LHsBinds GhcTc, [TcId])
forall a b. (a -> b) -> a -> b
$
    TcM (LHsBinds GhcTc, [TcId])
-> TcM (LHsBinds GhcTc, [TcId]) -> TcM (LHsBinds GhcTc, [TcId])
forall r. TcRn r -> TcRn r -> TcRn r
recoverM ([Name] -> TcSigFun -> TcM (LHsBinds GhcTc, [TcId])
recoveryCode [IdP GhcRn]
[Name]
binder_names TcSigFun
sig_fn) (TcM (LHsBinds GhcTc, [TcId]) -> TcM (LHsBinds GhcTc, [TcId]))
-> TcM (LHsBinds GhcTc, [TcId]) -> TcM (LHsBinds GhcTc, [TcId])
forall a b. (a -> b) -> a -> b
$ do
        -- Set up main recover; take advantage of any type sigs

    { String -> SDoc -> TcRn ()
traceTc String
"------------------------------------------------" SDoc
Outputable.empty
    ; String -> SDoc -> TcRn ()
traceTc String
"Bindings for {" ([Name] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [IdP GhcRn]
[Name]
binder_names)
    ; DynFlags
dflags   <- IOEnv (Env TcGblEnv TcLclEnv) DynFlags
forall (m :: * -> *). HasDynFlags m => m DynFlags
getDynFlags
    ; let plan :: GeneralisationPlan
plan = DynFlags
-> TopLevelFlag
-> IsGroupClosed
-> TcSigFun
-> [LHsBind GhcRn]
-> GeneralisationPlan
decideGeneralisationPlan DynFlags
dflags TopLevelFlag
top_lvl IsGroupClosed
closed TcSigFun
sig_fn [LHsBind GhcRn]
bind_list
    ; String -> SDoc -> TcRn ()
traceTc String
"Generalisation plan" (GeneralisationPlan -> SDoc
forall a. Outputable a => a -> SDoc
ppr GeneralisationPlan
plan)
    ; result :: (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
result@(Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
_, [TcId]
poly_ids) <- case GeneralisationPlan
plan of
         GeneralisationPlan
NoGen              -> RecFlag
-> TcPragEnv
-> TcSigFun
-> [LHsBind GhcRn]
-> TcM (LHsBinds GhcTc, [TcId])
tcPolyNoGen RecFlag
rec_tc TcPragEnv
prag_fn TcSigFun
sig_fn [LHsBind GhcRn]
bind_list
         InferGen Bool
mn        -> RecFlag
-> TcPragEnv
-> TcSigFun
-> Bool
-> [LHsBind GhcRn]
-> TcM (LHsBinds GhcTc, [TcId])
tcPolyInfer RecFlag
rec_tc TcPragEnv
prag_fn TcSigFun
sig_fn Bool
mn [LHsBind GhcRn]
bind_list
         CheckGen LHsBind GhcRn
lbind TcIdSigInfo
sig -> TcPragEnv
-> TcIdSigInfo -> LHsBind GhcRn -> TcM (LHsBinds GhcTc, [TcId])
tcPolyCheck TcPragEnv
prag_fn TcIdSigInfo
sig LHsBind GhcRn
lbind

    ; (TcId -> TcRn ()) -> [TcId] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (\ TcId
poly_id ->
        (() :: Constraint) => FixedRuntimeRepContext -> Kind -> TcRn ()
FixedRuntimeRepContext -> Kind -> TcRn ()
hasFixedRuntimeRep_syntactic (Name -> FixedRuntimeRepContext
FRRBinder (Name -> FixedRuntimeRepContext) -> Name -> FixedRuntimeRepContext
forall a b. (a -> b) -> a -> b
$ TcId -> Name
idName TcId
poly_id) (TcId -> Kind
idType TcId
poly_id))
        [TcId]
poly_ids

    ; String -> SDoc -> TcRn ()
traceTc String
"} End of bindings for" ([SDoc] -> SDoc
vcat [ [Name] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [IdP GhcRn]
[Name]
binder_names, RecFlag -> SDoc
forall a. Outputable a => a -> SDoc
ppr RecFlag
rec_group
                                            , [SDoc] -> SDoc
vcat [TcId -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcId
id SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TcId -> Kind
idType TcId
id) | TcId
id <- [TcId]
poly_ids]
                                          ])

    ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
result }
  where
    binder_names :: [IdP GhcRn]
binder_names = CollectFlag GhcRn -> [LHsBind GhcRn] -> [IdP GhcRn]
forall p idR.
CollectPass p =>
CollectFlag p -> [LHsBindLR p idR] -> [IdP p]
collectHsBindListBinders CollectFlag GhcRn
forall p. CollectFlag p
CollNoDictBinders [LHsBind GhcRn]
bind_list
    loc :: SrcSpan
loc = (SrcSpan -> SrcSpan -> SrcSpan) -> [SrcSpan] -> SrcSpan
forall a. (a -> a -> a) -> [a] -> a
forall (t :: * -> *) a. Foldable t => (a -> a -> a) -> t a -> a
foldr1 SrcSpan -> SrcSpan -> SrcSpan
combineSrcSpans ((GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn) -> SrcSpan)
-> [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)] -> [SrcSpan]
forall a b. (a -> b) -> [a] -> [b]
map (SrcSpanAnnA -> SrcSpan
forall a. SrcSpanAnn' a -> SrcSpan
locA (SrcSpanAnnA -> SrcSpan)
-> (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn) -> SrcSpanAnnA)
-> GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
-> SrcSpan
forall b c a. (b -> c) -> (a -> b) -> a -> c
. GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn) -> SrcSpanAnnA
forall l e. GenLocated l e -> l
getLoc) [LHsBind GhcRn]
[GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
bind_list)
         -- The mbinds have been dependency analysed and
         -- may no longer be adjacent; so find the narrowest
         -- span that includes them all

--------------
-- If typechecking the binds fails, then return with each
-- signature-less binder given type (forall a.a), to minimise
-- subsequent error messages
recoveryCode :: [Name] -> TcSigFun -> TcM (LHsBinds GhcTc, [Id])
recoveryCode :: [Name] -> TcSigFun -> TcM (LHsBinds GhcTc, [TcId])
recoveryCode [Name]
binder_names TcSigFun
sig_fn
  = do  { String -> SDoc -> TcRn ()
traceTc String
"tcBindsWithSigs: error recovery" ([Name] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Name]
binder_names)
        ; let poly_ids :: [TcId]
poly_ids = (Name -> TcId) -> [Name] -> [TcId]
forall a b. (a -> b) -> [a] -> [b]
map Name -> TcId
mk_dummy [Name]
binder_names
        ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a. Bag a
emptyBag, [TcId]
poly_ids) }
  where
    mk_dummy :: Name -> TcId
mk_dummy Name
name
      | Just TcSigInfo
sig <- TcSigFun
sig_fn Name
name
      , Just TcId
poly_id <- TcSigInfo -> Maybe TcId
completeSigPolyId_maybe TcSigInfo
sig
      = TcId
poly_id
      | Bool
otherwise
      = (() :: Constraint) => Name -> Kind -> Kind -> TcId
Name -> Kind -> Kind -> TcId
mkLocalId Name
name Kind
Many Kind
forall_a_a

forall_a_a :: TcType
-- At one point I had (forall r (a :: TYPE r). a), but of course
-- that type is ill-formed: its mentions 'r' which escapes r's scope.
-- Another alternative would be (forall (a :: TYPE kappa). a), where
-- kappa is a unification variable. But I don't think we need that
-- complication here. I'm going to just use (forall (a::*). a).
-- See #15276
forall_a_a :: Kind
forall_a_a = [TcId] -> Kind -> Kind
mkSpecForAllTys [TcId
alphaTyVar] Kind
alphaTy

{- *********************************************************************
*                                                                      *
                         tcPolyNoGen
*                                                                      *
********************************************************************* -}

tcPolyNoGen     -- No generalisation whatsoever
  :: RecFlag       -- Whether it's recursive after breaking
                   -- dependencies based on type signatures
  -> TcPragEnv -> TcSigFun
  -> [LHsBind GhcRn]
  -> TcM (LHsBinds GhcTc, [TcId])

tcPolyNoGen :: RecFlag
-> TcPragEnv
-> TcSigFun
-> [LHsBind GhcRn]
-> TcM (LHsBinds GhcTc, [TcId])
tcPolyNoGen RecFlag
rec_tc TcPragEnv
prag_fn TcSigFun
tc_sig_fn [LHsBind GhcRn]
bind_list
  = do { (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds', [MonoBindInfo]
mono_infos) <- RecFlag
-> TcSigFun
-> LetBndrSpec
-> [LHsBind GhcRn]
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
tcMonoBinds RecFlag
rec_tc TcSigFun
tc_sig_fn
                                             (TcPragEnv -> LetBndrSpec
LetGblBndr TcPragEnv
prag_fn)
                                             [LHsBind GhcRn]
bind_list
       ; [TcId]
mono_ids' <- (MonoBindInfo -> IOEnv (Env TcGblEnv TcLclEnv) TcId)
-> [MonoBindInfo] -> TcM [TcId]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM MonoBindInfo -> IOEnv (Env TcGblEnv TcLclEnv) TcId
tc_mono_info [MonoBindInfo]
mono_infos
       ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds', [TcId]
mono_ids') }
  where
    tc_mono_info :: MonoBindInfo -> IOEnv (Env TcGblEnv TcLclEnv) TcId
tc_mono_info (MBI { mbi_poly_name :: MonoBindInfo -> Name
mbi_poly_name = Name
name, mbi_mono_id :: MonoBindInfo -> TcId
mbi_mono_id = TcId
mono_id })
      = do { [LTcSpecPrag]
_specs <- TcId -> [LSig GhcRn] -> TcM [LTcSpecPrag]
tcSpecPrags TcId
mono_id (TcPragEnv -> Name -> [LSig GhcRn]
lookupPragEnv TcPragEnv
prag_fn Name
name)
           ; TcId -> IOEnv (Env TcGblEnv TcLclEnv) TcId
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return TcId
mono_id }
           -- NB: tcPrags generates error messages for
           --     specialisation pragmas for non-overloaded sigs
           -- Indeed that is why we call it here!
           -- So we can safely ignore _specs


{- *********************************************************************
*                                                                      *
                         tcPolyCheck
*                                                                      *
********************************************************************* -}

tcPolyCheck :: TcPragEnv
            -> TcIdSigInfo     -- Must be a complete signature
            -> LHsBind GhcRn   -- Must be a FunBind
            -> TcM (LHsBinds GhcTc, [TcId])
-- There is just one binding,
--   it is a FunBind
--   it has a complete type signature,
tcPolyCheck :: TcPragEnv
-> TcIdSigInfo -> LHsBind GhcRn -> TcM (LHsBinds GhcTc, [TcId])
tcPolyCheck TcPragEnv
prag_fn
            (CompleteSig { sig_bndr :: TcIdSigInfo -> TcId
sig_bndr  = TcId
poly_id
                         , sig_ctxt :: TcIdSigInfo -> UserTypeCtxt
sig_ctxt  = UserTypeCtxt
ctxt
                         , sig_loc :: TcIdSigInfo -> SrcSpan
sig_loc   = SrcSpan
sig_loc })
            (L SrcSpanAnnA
bind_loc (FunBind { fun_id :: forall idL idR. HsBindLR idL idR -> LIdP idL
fun_id = L SrcSpanAnnN
nm_loc Name
name
                                 , fun_matches :: forall idL idR. HsBindLR idL idR -> MatchGroup idR (LHsExpr idR)
fun_matches = MatchGroup GhcRn (LHsExpr GhcRn)
matches }))
  = do { String -> SDoc -> TcRn ()
traceTc String
"tcPolyCheck" (TcId -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcId
poly_id SDoc -> SDoc -> SDoc
$$ SrcSpan -> SDoc
forall a. Outputable a => a -> SDoc
ppr SrcSpan
sig_loc)

       ; Name
mono_name <- OccName -> SrcSpan -> TcM Name
newNameAt (Name -> OccName
nameOccName Name
name) (SrcSpanAnnN -> SrcSpan
forall a. SrcSpanAnn' a -> SrcSpan
locA SrcSpanAnnN
nm_loc)
       ; (HsWrapper
wrap_gen, (HsWrapper
wrap_res, MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))
matches'))
             <- SrcSpan
-> TcRn
     (HsWrapper,
      (HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
-> TcRn
     (HsWrapper,
      (HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
sig_loc (TcRn
   (HsWrapper,
    (HsWrapper,
     MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
 -> TcRn
      (HsWrapper,
       (HsWrapper,
        MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)))))
-> TcRn
     (HsWrapper,
      (HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
-> TcRn
     (HsWrapper,
      (HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
forall a b. (a -> b) -> a -> b
$ -- Sets the binding location for the skolems
                UserTypeCtxt
-> Kind
-> (Kind
    -> TcM
         (HsWrapper,
          MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
-> TcRn
     (HsWrapper,
      (HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
forall result.
UserTypeCtxt
-> Kind -> (Kind -> TcM result) -> TcM (HsWrapper, result)
tcSkolemiseScoped UserTypeCtxt
ctxt (TcId -> Kind
idType TcId
poly_id) ((Kind
  -> TcM
       (HsWrapper,
        MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
 -> TcRn
      (HsWrapper,
       (HsWrapper,
        MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)))))
-> (Kind
    -> TcM
         (HsWrapper,
          MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
-> TcRn
     (HsWrapper,
      (HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
forall a b. (a -> b) -> a -> b
$ \Kind
rho_ty ->
                -- Unwraps multiple layers; e.g
                --    f :: forall a. Eq a => forall b. Ord b => blah
                -- NB: tcSkolemiseScoped makes fresh type variables
                -- See Note [Instantiate sig with fresh variables]

                let mono_id :: TcId
mono_id = (() :: Constraint) => Name -> Kind -> Kind -> TcId
Name -> Kind -> Kind -> TcId
mkLocalId Name
mono_name (TcId -> Kind
varMult TcId
poly_id) Kind
rho_ty in
                [TcBinder]
-> TcM
     (HsWrapper,
      MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)))
-> TcM
     (HsWrapper,
      MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)))
forall a. [TcBinder] -> TcM a -> TcM a
tcExtendBinderStack [TcId -> TopLevelFlag -> TcBinder
TcIdBndr TcId
mono_id TopLevelFlag
NotTopLevel] (TcM
   (HsWrapper,
    MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)))
 -> TcM
      (HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
-> TcM
     (HsWrapper,
      MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)))
-> TcM
     (HsWrapper,
      MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)))
forall a b. (a -> b) -> a -> b
$
                -- Why mono_id in the BinderStack?
                --    See Note [Relevant bindings and the binder stack]

                SrcSpanAnnA
-> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
-> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
forall ann a. SrcSpanAnn' ann -> TcRn a -> TcRn a
setSrcSpanA SrcSpanAnnA
bind_loc (TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
 -> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc)))
-> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
-> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
forall a b. (a -> b) -> a -> b
$
                GenLocated SrcSpanAnnN TcId
-> MatchGroup GhcRn (LHsExpr GhcRn)
-> ExpSigmaType
-> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
tcMatchesFun (SrcSpanAnnN -> TcId -> GenLocated SrcSpanAnnN TcId
forall l e. l -> e -> GenLocated l e
L SrcSpanAnnN
nm_loc TcId
mono_id) MatchGroup GhcRn (LHsExpr GhcRn)
matches
                             (Kind -> ExpSigmaType
mkCheckExpType Kind
rho_ty)

       -- We make a funny AbsBinds, abstracting over nothing,
       -- just so we have somewhere to put the SpecPrags.
       -- Otherwise we could just use the FunBind
       -- Hence poly_id2 is just a clone of poly_id;
       -- We re-use mono-name, but we could equally well use a fresh one

       ; let prag_sigs :: [LSig GhcRn]
prag_sigs = TcPragEnv -> Name -> [LSig GhcRn]
lookupPragEnv TcPragEnv
prag_fn Name
name
             poly_id2 :: TcId
poly_id2  = (() :: Constraint) => Name -> Kind -> Kind -> TcId
Name -> Kind -> Kind -> TcId
mkLocalId Name
mono_name (TcId -> Kind
idMult TcId
poly_id) (TcId -> Kind
idType TcId
poly_id)
       ; [LTcSpecPrag]
spec_prags <- TcId -> [LSig GhcRn] -> TcM [LTcSpecPrag]
tcSpecPrags    TcId
poly_id [LSig GhcRn]
prag_sigs
       ; TcId
poly_id    <- TcId -> [LSig GhcRn] -> IOEnv (Env TcGblEnv TcLclEnv) TcId
addInlinePrags TcId
poly_id [LSig GhcRn]
prag_sigs

       ; Module
mod <- IOEnv (Env TcGblEnv TcLclEnv) Module
forall (m :: * -> *). HasModule m => m Module
getModule
       ; [CoreTickish]
tick <- SrcSpan -> TcId -> Module -> [LSig GhcRn] -> TcM [CoreTickish]
funBindTicks (SrcSpanAnnN -> SrcSpan
forall a. SrcSpanAnn' a -> SrcSpan
locA SrcSpanAnnN
nm_loc) TcId
poly_id Module
mod [LSig GhcRn]
prag_sigs

       ; let bind' :: HsBindLR GhcTc GhcTc
bind' = FunBind { fun_id :: LIdP GhcTc
fun_id      = SrcSpanAnnN -> TcId -> GenLocated SrcSpanAnnN TcId
forall l e. l -> e -> GenLocated l e
L SrcSpanAnnN
nm_loc TcId
poly_id2
                             , fun_matches :: MatchGroup GhcTc (LHsExpr GhcTc)
fun_matches = MatchGroup GhcTc (LHsExpr GhcTc)
MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))
matches'
                             , fun_ext :: XFunBind GhcTc GhcTc
fun_ext     = HsWrapper
wrap_gen HsWrapper -> HsWrapper -> HsWrapper
<.> HsWrapper
wrap_res
                             , fun_tick :: [CoreTickish]
fun_tick    = [CoreTickish]
tick }

             export :: ABExport
export = ABE { abe_wrap :: HsWrapper
abe_wrap  = HsWrapper
idHsWrapper
                          , abe_poly :: TcId
abe_poly  = TcId
poly_id
                          , abe_mono :: TcId
abe_mono  = TcId
poly_id2
                          , abe_prags :: TcSpecPrags
abe_prags = [LTcSpecPrag] -> TcSpecPrags
SpecPrags [LTcSpecPrag]
spec_prags }

             abs_bind :: GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
abs_bind = SrcSpanAnnA
-> HsBindLR GhcTc GhcTc
-> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
forall l e. l -> e -> GenLocated l e
L SrcSpanAnnA
bind_loc (HsBindLR GhcTc GhcTc
 -> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
-> HsBindLR GhcTc GhcTc
-> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
forall a b. (a -> b) -> a -> b
$ XXHsBindsLR GhcTc GhcTc -> HsBindLR GhcTc GhcTc
forall idL idR. XXHsBindsLR idL idR -> HsBindLR idL idR
XHsBindsLR (XXHsBindsLR GhcTc GhcTc -> HsBindLR GhcTc GhcTc)
-> XXHsBindsLR GhcTc GhcTc -> HsBindLR GhcTc GhcTc
forall a b. (a -> b) -> a -> b
$
                        AbsBinds { abs_tvs :: [TcId]
abs_tvs      = []
                                 , abs_ev_vars :: [TcId]
abs_ev_vars  = []
                                 , abs_ev_binds :: [TcEvBinds]
abs_ev_binds = []
                                 , abs_exports :: [ABExport]
abs_exports  = [ABExport
export]
                                 , abs_binds :: LHsBinds GhcTc
abs_binds    = GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a. a -> Bag a
unitBag (SrcSpanAnnA
-> HsBindLR GhcTc GhcTc
-> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
forall l e. l -> e -> GenLocated l e
L SrcSpanAnnA
bind_loc HsBindLR GhcTc GhcTc
bind')
                                 , abs_sig :: Bool
abs_sig      = Bool
True }

       ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a. a -> Bag a
unitBag GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
abs_bind, [TcId
poly_id]) }

tcPolyCheck TcPragEnv
_prag_fn TcIdSigInfo
sig LHsBind GhcRn
bind
  = String
-> SDoc
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"tcPolyCheck" (TcIdSigInfo -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcIdSigInfo
sig SDoc -> SDoc -> SDoc
$$ GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn) -> SDoc
forall a. Outputable a => a -> SDoc
ppr LHsBind GhcRn
GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind)

funBindTicks :: SrcSpan -> TcId -> Module -> [LSig GhcRn]
             -> TcM [CoreTickish]
funBindTicks :: SrcSpan -> TcId -> Module -> [LSig GhcRn] -> TcM [CoreTickish]
funBindTicks SrcSpan
loc TcId
fun_id Module
mod [LSig GhcRn]
sigs
  | (Maybe (GenLocated (SrcAnn NoEpAnns) StringLiteral)
mb_cc_str : [Maybe (GenLocated (SrcAnn NoEpAnns) StringLiteral)]
_) <- [ Maybe (XRec GhcRn StringLiteral)
Maybe (GenLocated (SrcAnn NoEpAnns) StringLiteral)
cc_name | L SrcSpanAnnA
_ (SCCFunSig XSCCFunSig GhcRn
_ SourceText
_ LIdP GhcRn
_ Maybe (XRec GhcRn StringLiteral)
cc_name) <- [LSig GhcRn]
[GenLocated SrcSpanAnnA (Sig GhcRn)]
sigs ]
      -- this can only be a singleton list, as duplicate pragmas are rejected
      -- by the renamer
  , let cc_str :: FastString
cc_str
          | Just GenLocated (SrcAnn NoEpAnns) StringLiteral
cc_str <- Maybe (GenLocated (SrcAnn NoEpAnns) StringLiteral)
mb_cc_str
          = StringLiteral -> FastString
sl_fs (StringLiteral -> FastString) -> StringLiteral -> FastString
forall a b. (a -> b) -> a -> b
$ GenLocated (SrcAnn NoEpAnns) StringLiteral -> StringLiteral
forall l e. GenLocated l e -> e
unLoc GenLocated (SrcAnn NoEpAnns) StringLiteral
cc_str
          | Bool
otherwise
          = Name -> FastString
forall a. NamedThing a => a -> FastString
getOccFS (TcId -> Name
Var.varName TcId
fun_id)
        cc_name :: FastString
cc_name = ModuleName -> FastString
moduleNameFS (Module -> ModuleName
forall unit. GenModule unit -> ModuleName
moduleName Module
mod) FastString -> FastString -> FastString
`appendFS` Char -> FastString -> FastString
consFS Char
'.' FastString
cc_str
  = do
      CCFlavour
flavour <- CostCentreIndex -> CCFlavour
DeclCC (CostCentreIndex -> CCFlavour)
-> IOEnv (Env TcGblEnv TcLclEnv) CostCentreIndex
-> IOEnv (Env TcGblEnv TcLclEnv) CCFlavour
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> FastString -> IOEnv (Env TcGblEnv TcLclEnv) CostCentreIndex
getCCIndexTcM FastString
cc_name
      let cc :: CostCentre
cc = FastString -> Module -> SrcSpan -> CCFlavour -> CostCentre
mkUserCC FastString
cc_name Module
mod SrcSpan
loc CCFlavour
flavour
      [CoreTickish] -> TcM [CoreTickish]
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return [CostCentre -> Bool -> Bool -> CoreTickish
forall (pass :: TickishPass).
CostCentre -> Bool -> Bool -> GenTickish pass
ProfNote CostCentre
cc Bool
True Bool
True]
  | Bool
otherwise
  = [CoreTickish] -> TcM [CoreTickish]
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return []

{- Note [Instantiate sig with fresh variables]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
It's vital to instantiate a type signature with fresh variables.
For example:
      type T = forall a. [a] -> [a]
      f :: T;
      f = g where { g :: T; g = <rhs> }

 We must not use the same 'a' from the defn of T at both places!!
(Instantiation is only necessary because of type synonyms.  Otherwise,
it's all cool; each signature has distinct type variables from the renamer.)
-}


{- *********************************************************************
*                                                                      *
                         tcPolyInfer
*                                                                      *
********************************************************************* -}

tcPolyInfer
  :: RecFlag       -- Whether it's recursive after breaking
                   -- dependencies based on type signatures
  -> TcPragEnv -> TcSigFun
  -> Bool         -- True <=> apply the monomorphism restriction
  -> [LHsBind GhcRn]
  -> TcM (LHsBinds GhcTc, [TcId])
tcPolyInfer :: RecFlag
-> TcPragEnv
-> TcSigFun
-> Bool
-> [LHsBind GhcRn]
-> TcM (LHsBinds GhcTc, [TcId])
tcPolyInfer RecFlag
rec_tc TcPragEnv
prag_fn TcSigFun
tc_sig_fn Bool
mono [LHsBind GhcRn]
bind_list
  = do { (TcLevel
tclvl, WantedConstraints
wanted, (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds', [MonoBindInfo]
mono_infos))
             <- TcM (LHsBinds GhcTc, [MonoBindInfo])
-> TcM
     (TcLevel, WantedConstraints, (LHsBinds GhcTc, [MonoBindInfo]))
forall a. TcM a -> TcM (TcLevel, WantedConstraints, a)
pushLevelAndCaptureConstraints  (TcM (LHsBinds GhcTc, [MonoBindInfo])
 -> TcM
      (TcLevel, WantedConstraints, (LHsBinds GhcTc, [MonoBindInfo])))
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
-> TcM
     (TcLevel, WantedConstraints, (LHsBinds GhcTc, [MonoBindInfo]))
forall a b. (a -> b) -> a -> b
$
                RecFlag
-> TcSigFun
-> LetBndrSpec
-> [LHsBind GhcRn]
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
tcMonoBinds RecFlag
rec_tc TcSigFun
tc_sig_fn LetBndrSpec
LetLclBndr [LHsBind GhcRn]
bind_list

       ; let name_taus :: [(Name, Kind)]
name_taus  = [ (MonoBindInfo -> Name
mbi_poly_name MonoBindInfo
info, TcId -> Kind
idType (MonoBindInfo -> TcId
mbi_mono_id MonoBindInfo
info))
                          | MonoBindInfo
info <- [MonoBindInfo]
mono_infos ]
             sigs :: [TcIdSigInst]
sigs       = [ TcIdSigInst
sig | MBI { mbi_sig :: MonoBindInfo -> Maybe TcIdSigInst
mbi_sig = Just TcIdSigInst
sig } <- [MonoBindInfo]
mono_infos ]
             infer_mode :: InferMode
infer_mode = if Bool
mono then InferMode
ApplyMR else InferMode
NoRestrictions

       ; (TcIdSigInst -> TcRn ()) -> [TcIdSigInst] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (Bool -> TcIdSigInst -> TcRn ()
checkOverloadedSig Bool
mono) [TcIdSigInst]
sigs

       ; String -> SDoc -> TcRn ()
traceTc String
"simplifyInfer call" (TcLevel -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcLevel
tclvl SDoc -> SDoc -> SDoc
$$ [(Name, Kind)] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [(Name, Kind)]
name_taus SDoc -> SDoc -> SDoc
$$ WantedConstraints -> SDoc
forall a. Outputable a => a -> SDoc
ppr WantedConstraints
wanted)
       ; (([TcId]
qtvs, [TcId]
givens, TcEvBinds
ev_binds, Bool
insoluble), WantedConstraints
residual)
            <- TcM ([TcId], [TcId], TcEvBinds, Bool)
-> TcM (([TcId], [TcId], TcEvBinds, Bool), WantedConstraints)
forall a. TcM a -> TcM (a, WantedConstraints)
captureConstraints (TcM ([TcId], [TcId], TcEvBinds, Bool)
 -> TcM (([TcId], [TcId], TcEvBinds, Bool), WantedConstraints))
-> TcM ([TcId], [TcId], TcEvBinds, Bool)
-> TcM (([TcId], [TcId], TcEvBinds, Bool), WantedConstraints)
forall a b. (a -> b) -> a -> b
$ TcLevel
-> InferMode
-> [TcIdSigInst]
-> [(Name, Kind)]
-> WantedConstraints
-> TcM ([TcId], [TcId], TcEvBinds, Bool)
simplifyInfer TcLevel
tclvl InferMode
infer_mode [TcIdSigInst]
sigs [(Name, Kind)]
name_taus WantedConstraints
wanted

       ; let inferred_theta :: TcThetaType
inferred_theta = (TcId -> Kind) -> [TcId] -> TcThetaType
forall a b. (a -> b) -> [a] -> [b]
map TcId -> Kind
evVarPred [TcId]
givens
       ; [ABExport]
exports <- TcM [ABExport] -> TcM [ABExport]
forall r. TcM r -> TcM r
checkNoErrs (TcM [ABExport] -> TcM [ABExport])
-> TcM [ABExport] -> TcM [ABExport]
forall a b. (a -> b) -> a -> b
$
                    (MonoBindInfo -> IOEnv (Env TcGblEnv TcLclEnv) ABExport)
-> [MonoBindInfo] -> TcM [ABExport]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM (TcPragEnv
-> WantedConstraints
-> Bool
-> [TcId]
-> TcThetaType
-> MonoBindInfo
-> IOEnv (Env TcGblEnv TcLclEnv) ABExport
mkExport TcPragEnv
prag_fn WantedConstraints
residual Bool
insoluble [TcId]
qtvs TcThetaType
inferred_theta) [MonoBindInfo]
mono_infos

         -- NB: *after* the checkNoErrs call above. This ensures that we don't get an error
         -- cascade in case mkExport runs into trouble. In particular, this avoids duplicate
         -- errors when a partial type signature cannot be quantified in chooseInferredQuantifiers.
         -- See Note [Quantification and partial signatures] in GHC.Tc.Solver, Wrinkle 4.
         -- Tested in partial-sigs/should_fail/NamedWilcardExplicitForall.
       ; WantedConstraints -> TcRn ()
emitConstraints WantedConstraints
residual

       ; SrcSpan
loc <- TcRn SrcSpan
getSrcSpanM
       ; let poly_ids :: [TcId]
poly_ids = (ABExport -> TcId) -> [ABExport] -> [TcId]
forall a b. (a -> b) -> [a] -> [b]
map ABExport -> TcId
abe_poly [ABExport]
exports
             abs_bind :: GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
abs_bind = SrcSpanAnnA
-> HsBindLR GhcTc GhcTc
-> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
forall l e. l -> e -> GenLocated l e
L (SrcSpan -> SrcSpanAnnA
forall ann. SrcSpan -> SrcAnn ann
noAnnSrcSpan SrcSpan
loc) (HsBindLR GhcTc GhcTc
 -> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
-> HsBindLR GhcTc GhcTc
-> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
forall a b. (a -> b) -> a -> b
$ XXHsBindsLR GhcTc GhcTc -> HsBindLR GhcTc GhcTc
forall idL idR. XXHsBindsLR idL idR -> HsBindLR idL idR
XHsBindsLR (XXHsBindsLR GhcTc GhcTc -> HsBindLR GhcTc GhcTc)
-> XXHsBindsLR GhcTc GhcTc -> HsBindLR GhcTc GhcTc
forall a b. (a -> b) -> a -> b
$
                        AbsBinds { abs_tvs :: [TcId]
abs_tvs = [TcId]
qtvs
                                 , abs_ev_vars :: [TcId]
abs_ev_vars = [TcId]
givens, abs_ev_binds :: [TcEvBinds]
abs_ev_binds = [TcEvBinds
ev_binds]
                                 , abs_exports :: [ABExport]
abs_exports = [ABExport]
exports, abs_binds :: LHsBinds GhcTc
abs_binds = LHsBinds GhcTc
Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
binds'
                                 , abs_sig :: Bool
abs_sig = Bool
False }

       ; String -> SDoc -> TcRn ()
traceTc String
"Binding:" ([(TcId, Kind)] -> SDoc
forall a. Outputable a => a -> SDoc
ppr ([TcId]
poly_ids [TcId] -> TcThetaType -> [(TcId, Kind)]
forall a b. [a] -> [b] -> [(a, b)]
`zip` (TcId -> Kind) -> [TcId] -> TcThetaType
forall a b. (a -> b) -> [a] -> [b]
map TcId -> Kind
idType [TcId]
poly_ids))
       ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), [TcId])
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a. a -> Bag a
unitBag GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
abs_bind, [TcId]
poly_ids) }
         -- poly_ids are guaranteed zonked by mkExport

--------------
mkExport :: TcPragEnv
         -> WantedConstraints  -- residual constraints, already emitted (for errors only)
         -> Bool                        -- True <=> there was an insoluble type error
                                        --          when typechecking the bindings
         -> [TyVar] -> TcThetaType      -- Both already zonked
         -> MonoBindInfo
         -> TcM ABExport
-- Only called for generalisation plan InferGen, not by CheckGen or NoGen
--
-- mkExport generates exports with
--      zonked type variables,
--      zonked poly_ids
-- The former is just because no further unifications will change
-- the quantified type variables, so we can fix their final form
-- right now.
-- The latter is needed because the poly_ids are used to extend the
-- type environment; see the invariant on GHC.Tc.Utils.Env.tcExtendIdEnv

-- Pre-condition: the qtvs and theta are already zonked

mkExport :: TcPragEnv
-> WantedConstraints
-> Bool
-> [TcId]
-> TcThetaType
-> MonoBindInfo
-> IOEnv (Env TcGblEnv TcLclEnv) ABExport
mkExport TcPragEnv
prag_fn WantedConstraints
residual Bool
insoluble [TcId]
qtvs TcThetaType
theta
         (MBI { mbi_poly_name :: MonoBindInfo -> Name
mbi_poly_name = Name
poly_name
              , mbi_sig :: MonoBindInfo -> Maybe TcIdSigInst
mbi_sig       = Maybe TcIdSigInst
mb_sig
              , mbi_mono_id :: MonoBindInfo -> TcId
mbi_mono_id   = TcId
mono_id })
  = do  { Kind
mono_ty <- Kind -> TcM Kind
zonkTcType (TcId -> Kind
idType TcId
mono_id)
        ; TcId
poly_id <- WantedConstraints
-> Bool
-> [TcId]
-> TcThetaType
-> Name
-> Maybe TcIdSigInst
-> Kind
-> IOEnv (Env TcGblEnv TcLclEnv) TcId
mkInferredPolyId WantedConstraints
residual Bool
insoluble [TcId]
qtvs TcThetaType
theta Name
poly_name Maybe TcIdSigInst
mb_sig Kind
mono_ty

        -- NB: poly_id has a zonked type
        ; TcId
poly_id <- TcId -> [LSig GhcRn] -> IOEnv (Env TcGblEnv TcLclEnv) TcId
addInlinePrags TcId
poly_id [LSig GhcRn]
prag_sigs
        ; [LTcSpecPrag]
spec_prags <- TcId -> [LSig GhcRn] -> TcM [LTcSpecPrag]
tcSpecPrags TcId
poly_id [LSig GhcRn]
prag_sigs
                -- tcPrags requires a zonked poly_id

        -- See Note [Impedance matching]
        -- NB: we have already done checkValidType, including an ambiguity check,
        --     on the type; either when we checked the sig or in mkInferredPolyId
        ; let poly_ty :: Kind
poly_ty     = TcId -> Kind
idType TcId
poly_id
              sel_poly_ty :: Kind
sel_poly_ty = [TcId] -> TcThetaType -> Kind -> Kind
mkInfSigmaTy [TcId]
qtvs TcThetaType
theta Kind
mono_ty
                -- This type is just going into tcSubType,
                -- so Inferred vs. Specified doesn't matter

        ; String -> SDoc -> TcRn ()
traceTc String
"mkExport" ([SDoc] -> SDoc
vcat [ TcId -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcId
poly_id SDoc -> SDoc -> SDoc
<+> SDoc
dcolon SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr Kind
poly_ty
                                   , Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr Kind
sel_poly_ty ])

        ; HsWrapper
wrap <- if Kind
sel_poly_ty Kind -> Kind -> Bool
`eqType` Kind
poly_ty  -- NB: eqType ignores visibility
                  then HsWrapper -> IOEnv (Env TcGblEnv TcLclEnv) HsWrapper
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return HsWrapper
idHsWrapper  -- Fast path; also avoids complaint when we infer
                                           -- an ambiguous type and have AllowAmbiguousType
                                           -- e..g infer  x :: forall a. F a -> Int
                  else CtOrigin
-> UserTypeCtxt
-> Kind
-> Kind
-> IOEnv (Env TcGblEnv TcLclEnv) HsWrapper
tcSubTypeSigma CtOrigin
GhcBug20076
                                      UserTypeCtxt
sig_ctxt Kind
sel_poly_ty Kind
poly_ty
                       -- as Note [Impedance matching] explains, this should never fail,
                       -- and thus we'll never see an error message. It *may* do
                       -- instantiation, but no message will ever be printed to the
                       -- user, and so we use Shouldn'tHappenOrigin.
                       -- Actually, there is a bug here: #20076. So we tell the user
                       -- that they hit the bug. Once #20076 is fixed, change this
                       -- back to Shouldn'tHappenOrigin.

        ; TcId -> Maybe TcIdSigInst -> TcRn ()
localSigWarn TcId
poly_id Maybe TcIdSigInst
mb_sig

        ; ABExport -> IOEnv (Env TcGblEnv TcLclEnv) ABExport
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (ABE { abe_wrap :: HsWrapper
abe_wrap = HsWrapper
wrap
                        -- abe_wrap :: (forall qtvs. theta => mono_ty) ~ idType poly_id
                      , abe_poly :: TcId
abe_poly  = TcId
poly_id
                      , abe_mono :: TcId
abe_mono  = TcId
mono_id
                      , abe_prags :: TcSpecPrags
abe_prags = [LTcSpecPrag] -> TcSpecPrags
SpecPrags [LTcSpecPrag]
spec_prags }) }
  where
    prag_sigs :: [LSig GhcRn]
prag_sigs = TcPragEnv -> Name -> [LSig GhcRn]
lookupPragEnv TcPragEnv
prag_fn Name
poly_name
    sig_ctxt :: UserTypeCtxt
sig_ctxt  = Name -> UserTypeCtxt
InfSigCtxt Name
poly_name

mkInferredPolyId :: WantedConstraints   -- the residual constraints, already emitted
                 -> Bool  -- True <=> there was an insoluble error when
                          --          checking the binding group for this Id
                 -> [TyVar] -> TcThetaType
                 -> Name -> Maybe TcIdSigInst -> TcType
                 -> TcM TcId
mkInferredPolyId :: WantedConstraints
-> Bool
-> [TcId]
-> TcThetaType
-> Name
-> Maybe TcIdSigInst
-> Kind
-> IOEnv (Env TcGblEnv TcLclEnv) TcId
mkInferredPolyId WantedConstraints
residual Bool
insoluble [TcId]
qtvs TcThetaType
inferred_theta Name
poly_name Maybe TcIdSigInst
mb_sig_inst Kind
mono_ty
  | Just (TISI { sig_inst_sig :: TcIdSigInst -> TcIdSigInfo
sig_inst_sig = TcIdSigInfo
sig })  <- Maybe TcIdSigInst
mb_sig_inst
  , CompleteSig { sig_bndr :: TcIdSigInfo -> TcId
sig_bndr = TcId
poly_id } <- TcIdSigInfo
sig
  = TcId -> IOEnv (Env TcGblEnv TcLclEnv) TcId
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return TcId
poly_id

  | Bool
otherwise  -- Either no type sig or partial type sig
  = IOEnv (Env TcGblEnv TcLclEnv) TcId
-> IOEnv (Env TcGblEnv TcLclEnv) TcId
forall r. TcM r -> TcM r
checkNoErrs (IOEnv (Env TcGblEnv TcLclEnv) TcId
 -> IOEnv (Env TcGblEnv TcLclEnv) TcId)
-> IOEnv (Env TcGblEnv TcLclEnv) TcId
-> IOEnv (Env TcGblEnv TcLclEnv) TcId
forall a b. (a -> b) -> a -> b
$  -- The checkNoErrs ensures that if the type is ambiguous
                   -- we don't carry on to the impedance matching, and generate
                   -- a duplicate ambiguity error.  There is a similar
                   -- checkNoErrs for complete type signatures too.
    do { FamInstEnvs
fam_envs <- TcM FamInstEnvs
tcGetFamInstEnvs
       ; let mono_ty' :: Kind
mono_ty' = Reduction -> Kind
reductionReducedType (Reduction -> Kind) -> Reduction -> Kind
forall a b. (a -> b) -> a -> b
$ FamInstEnvs -> Role -> Kind -> Reduction
normaliseType FamInstEnvs
fam_envs Role
Nominal Kind
mono_ty
               -- Unification may not have normalised the type,
               -- so do it here to make it as uncomplicated as possible.
               -- Example: f :: [F Int] -> Bool
               -- should be rewritten to f :: [Char] -> Bool, if possible
               --
               -- We can discard the coercion _co, because we'll reconstruct
               -- it in the call to tcSubType below

       ; ([InvisTVBinder]
binders, TcThetaType
theta') <- WantedConstraints
-> TcThetaType
-> TcTyVarSet
-> [TcId]
-> Maybe TcIdSigInst
-> TcM ([InvisTVBinder], TcThetaType)
chooseInferredQuantifiers WantedConstraints
residual TcThetaType
inferred_theta
                                (Kind -> TcTyVarSet
tyCoVarsOfType Kind
mono_ty') [TcId]
qtvs Maybe TcIdSigInst
mb_sig_inst

       ; let inferred_poly_ty :: Kind
inferred_poly_ty = [InvisTVBinder] -> Kind -> Kind
mkInvisForAllTys [InvisTVBinder]
binders (TcThetaType -> Kind -> Kind
mkPhiTy TcThetaType
theta' Kind
mono_ty')

       ; String -> SDoc -> TcRn ()
traceTc String
"mkInferredPolyId" ([SDoc] -> SDoc
vcat [Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
poly_name, [TcId] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TcId]
qtvs, TcThetaType -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcThetaType
theta'
                                          , Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr Kind
inferred_poly_ty])
       ; Bool -> TcRn () -> TcRn ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
unless Bool
insoluble (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
         (TidyEnv -> TcM (TidyEnv, SDoc)) -> TcRn () -> TcRn ()
forall a. (TidyEnv -> TcM (TidyEnv, SDoc)) -> TcM a -> TcM a
addErrCtxtM (Name -> Kind -> TidyEnv -> TcM (TidyEnv, SDoc)
mk_inf_msg Name
poly_name Kind
inferred_poly_ty) (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
         UserTypeCtxt -> Kind -> TcRn ()
checkValidType (Name -> UserTypeCtxt
InfSigCtxt Name
poly_name) Kind
inferred_poly_ty
         -- See Note [Validity of inferred types]
         -- If we found an insoluble error in the function definition, don't
         -- do this check; otherwise (#14000) we may report an ambiguity
         -- error for a rather bogus type.

       ; TcId -> IOEnv (Env TcGblEnv TcLclEnv) TcId
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ((() :: Constraint) => Name -> Kind -> Kind -> TcId
Name -> Kind -> Kind -> TcId
mkLocalId Name
poly_name Kind
Many Kind
inferred_poly_ty) }


chooseInferredQuantifiers :: WantedConstraints  -- residual constraints
                          -> TcThetaType   -- inferred
                          -> TcTyVarSet    -- tvs free in tau type
                          -> [TcTyVar]     -- inferred quantified tvs
                          -> Maybe TcIdSigInst
                          -> TcM ([InvisTVBinder], TcThetaType)
chooseInferredQuantifiers :: WantedConstraints
-> TcThetaType
-> TcTyVarSet
-> [TcId]
-> Maybe TcIdSigInst
-> TcM ([InvisTVBinder], TcThetaType)
chooseInferredQuantifiers WantedConstraints
_residual TcThetaType
inferred_theta TcTyVarSet
tau_tvs [TcId]
qtvs Maybe TcIdSigInst
Nothing
  = -- No type signature (partial or complete) for this binder,
    do { let free_tvs :: TcTyVarSet
free_tvs = TcTyVarSet -> TcTyVarSet
closeOverKinds (TcThetaType -> TcTyVarSet -> TcTyVarSet
growThetaTyVars TcThetaType
inferred_theta TcTyVarSet
tau_tvs)
                        -- See Note [growThetaTyVars vs closeWrtFunDeps] in GHC.Tc.Solver
                        -- Include kind variables!  #7916
             my_theta :: TcThetaType
my_theta = TcTyVarSet -> TcThetaType -> TcThetaType
pickCapturedPreds TcTyVarSet
free_tvs TcThetaType
inferred_theta
             binders :: [InvisTVBinder]
binders  = [ Specificity -> TcId -> InvisTVBinder
forall vis. vis -> TcId -> VarBndr TcId vis
mkTyVarBinder Specificity
InferredSpec TcId
tv
                        | TcId
tv <- [TcId]
qtvs
                        , TcId
tv TcId -> TcTyVarSet -> Bool
`elemVarSet` TcTyVarSet
free_tvs ]
       ; ([InvisTVBinder], TcThetaType)
-> TcM ([InvisTVBinder], TcThetaType)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ([InvisTVBinder]
binders, TcThetaType
my_theta) }

chooseInferredQuantifiers WantedConstraints
residual TcThetaType
inferred_theta TcTyVarSet
tau_tvs [TcId]
qtvs
  (Just (TISI { sig_inst_sig :: TcIdSigInst -> TcIdSigInfo
sig_inst_sig   = sig :: TcIdSigInfo
sig@(PartialSig { psig_name :: TcIdSigInfo -> Name
psig_name = Name
fn_name, psig_hs_ty :: TcIdSigInfo -> LHsSigWcType GhcRn
psig_hs_ty = LHsSigWcType GhcRn
hs_ty })
              , sig_inst_wcx :: TcIdSigInst -> Maybe Kind
sig_inst_wcx   = Maybe Kind
wcx
              , sig_inst_theta :: TcIdSigInst -> TcThetaType
sig_inst_theta = TcThetaType
annotated_theta
              , sig_inst_skols :: TcIdSigInst -> [(Name, InvisTVBinder)]
sig_inst_skols = [(Name, InvisTVBinder)]
annotated_tvs }))
  = -- Choose quantifiers for a partial type signature
    do { let ([Name]
psig_qtv_nms, [InvisTVBinder]
psig_qtv_bndrs) = [(Name, InvisTVBinder)] -> ([Name], [InvisTVBinder])
forall a b. [(a, b)] -> ([a], [b])
unzip [(Name, InvisTVBinder)]
annotated_tvs
       ; [InvisTVBinder]
psig_qtv_bndrs <- (InvisTVBinder -> IOEnv (Env TcGblEnv TcLclEnv) InvisTVBinder)
-> [InvisTVBinder] -> IOEnv (Env TcGblEnv TcLclEnv) [InvisTVBinder]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM InvisTVBinder -> IOEnv (Env TcGblEnv TcLclEnv) InvisTVBinder
forall spec. VarBndr TcId spec -> TcM (VarBndr TcId spec)
zonkInvisTVBinder [InvisTVBinder]
psig_qtv_bndrs
       ; let psig_qtvs :: [TcId]
psig_qtvs    = (InvisTVBinder -> TcId) -> [InvisTVBinder] -> [TcId]
forall a b. (a -> b) -> [a] -> [b]
map InvisTVBinder -> TcId
forall tv argf. VarBndr tv argf -> tv
binderVar [InvisTVBinder]
psig_qtv_bndrs
             psig_qtv_set :: TcTyVarSet
psig_qtv_set = [TcId] -> TcTyVarSet
mkVarSet [TcId]
psig_qtvs
             psig_qtv_prs :: [(Name, TcId)]
psig_qtv_prs = [Name]
psig_qtv_nms [Name] -> [TcId] -> [(Name, TcId)]
forall a b. [a] -> [b] -> [(a, b)]
`zip` [TcId]
psig_qtvs


            -- Check whether the quantified variables of the
            -- partial signature have been unified together
            -- See Note [Quantified variables in partial type signatures]
       ; ((Name, Name) -> TcRn ()) -> [(Name, Name)] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (Name, Name) -> TcRn ()
report_dup_tyvar_tv_err  ([(Name, TcId)] -> [(Name, Name)]
findDupTyVarTvs [(Name, TcId)]
psig_qtv_prs)

            -- Check whether a quantified variable of the partial type
            -- signature is not actually quantified.  How can that happen?
            -- See Note [Quantification and partial signatures] Wrinkle 4
            --     in GHC.Tc.Solver
       ; ((Name, TcId) -> TcRn ()) -> [(Name, TcId)] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (Name, TcId) -> TcRn ()
report_mono_sig_tv_err [ (Name, TcId)
pr | pr :: (Name, TcId)
pr@(Name
_,TcId
tv) <- [(Name, TcId)]
psig_qtv_prs
                                           , Bool -> Bool
not (TcId
tv TcId -> [TcId] -> Bool
forall a. Eq a => a -> [a] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` [TcId]
qtvs) ]

       ; TcThetaType
annotated_theta      <- TcThetaType -> TcM TcThetaType
zonkTcTypes TcThetaType
annotated_theta
       ; (TcTyVarSet
free_tvs, TcThetaType
my_theta) <- TcTyVarSet
-> TcThetaType -> Maybe Kind -> TcM (TcTyVarSet, TcThetaType)
choose_psig_context TcTyVarSet
psig_qtv_set TcThetaType
annotated_theta Maybe Kind
wcx

       ; let keep_me :: TcTyVarSet
keep_me    = TcTyVarSet
free_tvs TcTyVarSet -> TcTyVarSet -> TcTyVarSet
`unionVarSet` TcTyVarSet
psig_qtv_set
             final_qtvs :: [InvisTVBinder]
final_qtvs = [ Specificity -> TcId -> InvisTVBinder
forall vis. vis -> TcId -> VarBndr TcId vis
mkTyVarBinder Specificity
vis TcId
tv
                          | TcId
tv <- [TcId]
qtvs -- Pulling from qtvs maintains original order
                          , TcId
tv TcId -> TcTyVarSet -> Bool
`elemVarSet` TcTyVarSet
keep_me
                          , let vis :: Specificity
vis = case TcId -> [InvisTVBinder] -> Maybe Specificity
forall var flag. Eq var => var -> [VarBndr var flag] -> Maybe flag
lookupVarBndr TcId
tv [InvisTVBinder]
psig_qtv_bndrs of
                                  Just Specificity
spec -> Specificity
spec
                                  Maybe Specificity
Nothing   -> Specificity
InferredSpec ]

       ; ([InvisTVBinder], TcThetaType)
-> TcM ([InvisTVBinder], TcThetaType)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ([InvisTVBinder]
final_qtvs, TcThetaType
my_theta) }
  where
    report_dup_tyvar_tv_err :: (Name, Name) -> TcRn ()
report_dup_tyvar_tv_err (Name
n1,Name
n2)
      = TcRnMessage -> TcRn ()
addErrTc (Name -> Name -> Name -> LHsSigWcType GhcRn -> TcRnMessage
TcRnPartialTypeSigTyVarMismatch Name
n1 Name
n2 Name
fn_name LHsSigWcType GhcRn
hs_ty)

    report_mono_sig_tv_err :: (Name, TcId) -> TcRn ()
report_mono_sig_tv_err (Name
n,TcId
tv)
      = TcRnMessage -> TcRn ()
addErrTc (Name -> Name -> Maybe Kind -> LHsSigWcType GhcRn -> TcRnMessage
TcRnPartialTypeSigBadQuantifier Name
n Name
fn_name Maybe Kind
m_unif_ty LHsSigWcType GhcRn
hs_ty)
      where
        m_unif_ty :: Maybe Kind
m_unif_ty = TcThetaType -> Maybe Kind
forall a. [a] -> Maybe a
listToMaybe
                      [ Kind
rhs
                      -- recall that residuals are always implications
                      | Implication
residual_implic <- Bag Implication -> [Implication]
forall a. Bag a -> [a]
bagToList (Bag Implication -> [Implication])
-> Bag Implication -> [Implication]
forall a b. (a -> b) -> a -> b
$ WantedConstraints -> Bag Implication
wc_impl WantedConstraints
residual
                      , Ct
residual_ct <- Bag Ct -> [Ct]
forall a. Bag a -> [a]
bagToList (Bag Ct -> [Ct]) -> Bag Ct -> [Ct]
forall a b. (a -> b) -> a -> b
$ WantedConstraints -> Bag Ct
wc_simple (Implication -> WantedConstraints
ic_wanted Implication
residual_implic)
                      , let residual_pred :: Kind
residual_pred = Ct -> Kind
ctPred Ct
residual_ct
                      , Just (Role
Nominal, Kind
lhs, Kind
rhs) <- [ Kind -> Maybe (Role, Kind, Kind)
getEqPredTys_maybe Kind
residual_pred ]
                      , Just TcId
lhs_tv <- [ Kind -> Maybe TcId
tcGetTyVar_maybe Kind
lhs ]
                      , TcId
lhs_tv TcId -> TcId -> Bool
forall a. Eq a => a -> a -> Bool
== TcId
tv ]

    choose_psig_context :: VarSet -> TcThetaType -> Maybe TcType
                        -> TcM (VarSet, TcThetaType)
    choose_psig_context :: TcTyVarSet
-> TcThetaType -> Maybe Kind -> TcM (TcTyVarSet, TcThetaType)
choose_psig_context TcTyVarSet
_ TcThetaType
annotated_theta Maybe Kind
Nothing
      = do { let free_tvs :: TcTyVarSet
free_tvs = TcTyVarSet -> TcTyVarSet
closeOverKinds (TcThetaType -> TcTyVarSet
tyCoVarsOfTypes TcThetaType
annotated_theta
                                            TcTyVarSet -> TcTyVarSet -> TcTyVarSet
`unionVarSet` TcTyVarSet
tau_tvs)
           ; (TcTyVarSet, TcThetaType) -> TcM (TcTyVarSet, TcThetaType)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (TcTyVarSet
free_tvs, TcThetaType
annotated_theta) }

    choose_psig_context TcTyVarSet
psig_qtvs TcThetaType
annotated_theta (Just Kind
wc_var_ty)
      = do { let free_tvs :: TcTyVarSet
free_tvs = TcTyVarSet -> TcTyVarSet
closeOverKinds (TcThetaType -> TcTyVarSet -> TcTyVarSet
growThetaTyVars TcThetaType
inferred_theta TcTyVarSet
seed_tvs)
                            -- growThetaTyVars just like the no-type-sig case
                            -- See Note [growThetaTyVars vs closeWrtFunDeps] in GHC.Tc.Solver
                            -- Omitting this caused #12844
                 seed_tvs :: TcTyVarSet
seed_tvs = TcThetaType -> TcTyVarSet
tyCoVarsOfTypes TcThetaType
annotated_theta  -- These are put there
                            TcTyVarSet -> TcTyVarSet -> TcTyVarSet
`unionVarSet` TcTyVarSet
tau_tvs            --       by the user

           ; let keep_me :: TcTyVarSet
keep_me  = TcTyVarSet
psig_qtvs TcTyVarSet -> TcTyVarSet -> TcTyVarSet
`unionVarSet` TcTyVarSet
free_tvs
                 my_theta :: TcThetaType
my_theta = TcTyVarSet -> TcThetaType -> TcThetaType
pickCapturedPreds TcTyVarSet
keep_me TcThetaType
inferred_theta

           -- Fill in the extra-constraints wildcard hole with inferred_theta,
           -- so that the Hole constraint we have already emitted
           -- (in tcHsPartialSigType) can report what filled it in.
           -- NB: my_theta already includes all the annotated constraints
           ; TcThetaType
diff_theta <- TcThetaType -> TcThetaType -> TcM TcThetaType
findInferredDiff TcThetaType
annotated_theta TcThetaType
my_theta

           ; case Kind -> Maybe (TcId, TcCoercionR)
tcGetCastedTyVar_maybe Kind
wc_var_ty of
               -- We know that wc_co must have type kind(wc_var) ~ Constraint, as it
               -- comes from the checkExpectedKind in GHC.Tc.Gen.HsType.tcAnonWildCardOcc.
               -- So, to make the kinds work out, we reverse the cast here.
               Just (TcId
wc_var, TcCoercionR
wc_co) -> TcId -> Kind -> TcRn ()
writeMetaTyVar TcId
wc_var (TcThetaType -> Kind
mk_ctuple TcThetaType
diff_theta
                                                              Kind -> TcCoercionR -> Kind
`mkCastTy` TcCoercionR -> TcCoercionR
mkTcSymCo TcCoercionR
wc_co)
               Maybe (TcId, TcCoercionR)
Nothing              -> String -> SDoc -> TcRn ()
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"chooseInferredQuantifiers 1" (Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr Kind
wc_var_ty)

           ; String -> SDoc -> TcRn ()
traceTc String
"completeTheta" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
forall a b. (a -> b) -> a -> b
$
                [SDoc] -> SDoc
vcat [ TcIdSigInfo -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcIdSigInfo
sig
                     , String -> SDoc
text String
"annotated_theta:" SDoc -> SDoc -> SDoc
<+> TcThetaType -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcThetaType
annotated_theta
                     , String -> SDoc
text String
"inferred_theta:" SDoc -> SDoc -> SDoc
<+> TcThetaType -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcThetaType
inferred_theta
                     , String -> SDoc
text String
"my_theta:" SDoc -> SDoc -> SDoc
<+> TcThetaType -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcThetaType
my_theta
                     , String -> SDoc
text String
"diff_theta:" SDoc -> SDoc -> SDoc
<+> TcThetaType -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcThetaType
diff_theta ]
           ; (TcTyVarSet, TcThetaType) -> TcM (TcTyVarSet, TcThetaType)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (TcTyVarSet
free_tvs, TcThetaType
annotated_theta TcThetaType -> TcThetaType -> TcThetaType
forall a. [a] -> [a] -> [a]
++ TcThetaType
diff_theta) }
             -- Return (annotated_theta ++ diff_theta)
             -- See Note [Extra-constraints wildcards]

    mk_ctuple :: TcThetaType -> Kind
mk_ctuple TcThetaType
preds = TcThetaType -> Kind
mkBoxedTupleTy TcThetaType
preds
       -- Hack alert!  See GHC.Tc.Gen.HsType:
       -- Note [Extra-constraint holes in partial type signatures]

chooseInferredQuantifiers WantedConstraints
_ TcThetaType
_ TcTyVarSet
_ [TcId]
_ (Just (TISI { sig_inst_sig :: TcIdSigInst -> TcIdSigInfo
sig_inst_sig = sig :: TcIdSigInfo
sig@(CompleteSig {}) }))
  = String -> SDoc -> TcM ([InvisTVBinder], TcThetaType)
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"chooseInferredQuantifiers" (TcIdSigInfo -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcIdSigInfo
sig)

mk_inf_msg :: Name -> TcType -> TidyEnv -> TcM (TidyEnv, SDoc)
mk_inf_msg :: Name -> Kind -> TidyEnv -> TcM (TidyEnv, SDoc)
mk_inf_msg Name
poly_name Kind
poly_ty TidyEnv
tidy_env
 = do { (TidyEnv
tidy_env1, Kind
poly_ty) <- TidyEnv -> Kind -> TcM (TidyEnv, Kind)
zonkTidyTcType TidyEnv
tidy_env Kind
poly_ty
      ; let msg :: SDoc
msg = [SDoc] -> SDoc
vcat [ String -> SDoc
text String
"When checking the inferred type"
                       , BKey -> SDoc -> SDoc
nest BKey
2 (SDoc -> SDoc) -> SDoc -> SDoc
forall a b. (a -> b) -> a -> b
$ Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
poly_name SDoc -> SDoc -> SDoc
<+> SDoc
dcolon SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr Kind
poly_ty ]
      ; (TidyEnv, SDoc) -> TcM (TidyEnv, SDoc)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (TidyEnv
tidy_env1, SDoc
msg) }

-- | Warn the user about polymorphic local binders that lack type signatures.
localSigWarn :: Id -> Maybe TcIdSigInst -> TcM ()
localSigWarn :: TcId -> Maybe TcIdSigInst -> TcRn ()
localSigWarn TcId
id Maybe TcIdSigInst
mb_sig
  | Just TcIdSigInst
_ <- Maybe TcIdSigInst
mb_sig               = () -> TcRn ()
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ()
  | Bool -> Bool
not (Kind -> Bool
isSigmaTy (TcId -> Kind
idType TcId
id))    = () -> TcRn ()
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ()
  | Bool
otherwise                      = TcId -> TcRn ()
warnMissingSignatures TcId
id

warnMissingSignatures :: Id -> TcM ()
warnMissingSignatures :: TcId -> TcRn ()
warnMissingSignatures TcId
id
  = do  { TidyEnv
env0 <- TcM TidyEnv
tcInitTidyEnv
        ; let (TidyEnv
env1, Kind
tidy_ty) = TidyEnv -> Kind -> (TidyEnv, Kind)
tidyOpenType TidyEnv
env0 (TcId -> Kind
idType TcId
id)
        ; let dia :: TcRnMessage
dia = Name -> Kind -> TcRnMessage
TcRnPolymorphicBinderMissingSig (TcId -> Name
idName TcId
id) Kind
tidy_ty
        ; (TidyEnv, TcRnMessage) -> TcRn ()
addDiagnosticTcM (TidyEnv
env1, TcRnMessage
dia) }

checkOverloadedSig :: Bool -> TcIdSigInst -> TcM ()
-- Example:
--   f :: Eq a => a -> a
--   K f = e
-- The MR applies, but the signature is overloaded, and it's
-- best to complain about this directly
-- c.f #11339
checkOverloadedSig :: Bool -> TcIdSigInst -> TcRn ()
checkOverloadedSig Bool
monomorphism_restriction_applies TcIdSigInst
sig
  | Bool -> Bool
not (TcThetaType -> Bool
forall a. [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null (TcIdSigInst -> TcThetaType
sig_inst_theta TcIdSigInst
sig))
  , Bool
monomorphism_restriction_applies
  , let orig_sig :: TcIdSigInfo
orig_sig = TcIdSigInst -> TcIdSigInfo
sig_inst_sig TcIdSigInst
sig
  = SrcSpan -> TcRn () -> TcRn ()
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan (TcIdSigInfo -> SrcSpan
sig_loc TcIdSigInfo
orig_sig) (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
    TcRnMessage -> TcRn ()
forall a. TcRnMessage -> TcRn a
failWith (TcRnMessage -> TcRn ()) -> TcRnMessage -> TcRn ()
forall a b. (a -> b) -> a -> b
$ TcIdSigInfo -> TcRnMessage
TcRnOverloadedSig TcIdSigInfo
orig_sig
  | Bool
otherwise
  = () -> TcRn ()
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ()

{- Note [Partial type signatures and generalisation]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If /any/ of the signatures in the group is a partial type signature
   f :: _ -> Int
then we *always* use the InferGen plan, and hence tcPolyInfer.
We do this even for a local binding with -XMonoLocalBinds, when
we normally use NoGen.

Reasons:
  * The TcSigInfo for 'f' has a unification variable for the '_',
    whose TcLevel is one level deeper than the current level.
    (See pushTcLevelM in tcTySig.)  But NoGen doesn't increase
    the TcLevel like InferGen, so we lose the level invariant.

  * The signature might be   f :: forall a. _ -> a
    so it really is polymorphic.  It's not clear what it would
    mean to use NoGen on this, and indeed the ASSERT in tcLhs,
    in the (Just sig) case, checks that if there is a signature
    then we are using LetLclBndr, and hence a nested AbsBinds with
    increased TcLevel

It might be possible to fix these difficulties somehow, but there
doesn't seem much point.  Indeed, adding a partial type signature is a
way to get per-binding inferred generalisation.

We apply the MR if /all/ of the partial signatures lack a context.
In particular (#11016):
   f2 :: (?loc :: Int) => _
   f2 = ?loc
It's stupid to apply the MR here.  This test includes an extra-constraints
wildcard; that is, we don't apply the MR if you write
   f3 :: _ => blah

Note [Quantified variables in partial type signatures]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider
  f :: forall a. a -> a -> _
  f x y = g x y
  g :: forall b. b -> b -> _
  g x y = [x, y]

Here, 'f' and 'g' are mutually recursive, and we end up unifying 'a' and 'b'
together, which is fine.  So we bind 'a' and 'b' to TyVarTvs, which can then
unify with each other.

But now consider:
  f :: forall a b. a -> b -> _
  f x y = [x, y]

We want to get an error from this, because 'a' and 'b' get unified.
So we make a test, one per partial signature, to check that the
explicitly-quantified type variables have not been unified together.
#14449 showed this up.

Note [Extra-constraints wildcards]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider this from #18646
    class Foo x where
      foo :: x

    bar :: (Foo (), _) => f ()
    bar = pure foo

We get [W] Foo (), [W] Applicative f.   When we do pickCapturedPreds in
choose_psig_context, we'll discard Foo ()!  Usually would not quantify over
such (closed) predicates.  So my_theta will be (Applicative f). But we really
do want to quantify over (Foo ()) -- it was speicfied by the programmer.
Solution: always return annotated_theta (user-specified) plus the extra piece
diff_theta.

Note [Validity of inferred types]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We need to check inferred type for validity, in case it uses language
extensions that are not turned on.  The principle is that if the user
simply adds the inferred type to the program source, it'll compile fine.
See #8883.

Examples that might fail:
 - the type might be ambiguous

 - an inferred theta that requires type equalities e.g. (F a ~ G b)
                                or multi-parameter type classes
 - an inferred type that includes unboxed tuples

Note [Impedance matching]
~~~~~~~~~~~~~~~~~~~~~~~~~
Consider
   f 0 x = x
   f n x = g [] (not x)

   g [] y = f 10 y
   g _  y = f 9  y

After typechecking we'll get
  f_mono_ty :: a -> Bool -> Bool
  g_mono_ty :: [b] -> Bool -> Bool
with constraints
  (Eq a, Num a)

Note that f is polymorphic in 'a' and g in 'b'; and these are not linked.
The types we really want for f and g are
   f :: forall a. (Eq a, Num a) => a -> Bool -> Bool
   g :: forall b. [b] -> Bool -> Bool

We can get these by "impedance matching":
   tuple :: forall a b. (Eq a, Num a) => (a -> Bool -> Bool, [b] -> Bool -> Bool)
   tuple a b d1 d1 = let ...bind f_mono, g_mono in (f_mono, g_mono)

   f a d1 d2 = case tuple a Any d1 d2 of (f_mono, g_mono) -> f_mono
   g b = case tuple Integer b dEqInteger dNumInteger of (f_mono,g_mono) -> g_mono

Suppose the shared quantified tyvars are qtvs and constraints theta.
Then we want to check that
     forall qtvs. theta => f_mono_ty   is more polymorphic than   f's polytype
and the proof is the impedance matcher.

Notice that the impedance matcher may do defaulting.  See #7173.

If we've gotten the constraints right during inference (and we assume we have),
this sub-type check should never fail. It's not really a check -- it's more of
a procedure to produce the right wrapper.

Note [SPECIALISE pragmas]
~~~~~~~~~~~~~~~~~~~~~~~~~
There is no point in a SPECIALISE pragma for a non-overloaded function:
   reverse :: [a] -> [a]
   {-# SPECIALISE reverse :: [Int] -> [Int] #-}

But SPECIALISE INLINE *can* make sense for GADTS:
   data Arr e where
     ArrInt :: !Int -> ByteArray# -> Arr Int
     ArrPair :: !Int -> Arr e1 -> Arr e2 -> Arr (e1, e2)

   (!:) :: Arr e -> Int -> e
   {-# SPECIALISE INLINE (!:) :: Arr Int -> Int -> Int #-}
   {-# SPECIALISE INLINE (!:) :: Arr (a, b) -> Int -> (a, b) #-}
   (ArrInt _ ba)     !: (I# i) = I# (indexIntArray# ba i)
   (ArrPair _ a1 a2) !: i      = (a1 !: i, a2 !: i)

When (!:) is specialised it becomes non-recursive, and can usefully
be inlined.  Scary!  So we only warn for SPECIALISE *without* INLINE
for a non-overloaded function.

************************************************************************
*                                                                      *
                         tcMonoBinds
*                                                                      *
************************************************************************

@tcMonoBinds@ deals with a perhaps-recursive group of HsBinds.
The signatures have been dealt with already.
-}

data MonoBindInfo = MBI { MonoBindInfo -> Name
mbi_poly_name :: Name
                        , MonoBindInfo -> Maybe TcIdSigInst
mbi_sig       :: Maybe TcIdSigInst
                        , MonoBindInfo -> TcId
mbi_mono_id   :: TcId }

tcMonoBinds :: RecFlag  -- Whether the binding is recursive for typechecking purposes
                        -- i.e. the binders are mentioned in their RHSs, and
                        --      we are not rescued by a type signature
            -> TcSigFun -> LetBndrSpec
            -> [LHsBind GhcRn]
            -> TcM (LHsBinds GhcTc, [MonoBindInfo])

-- SPECIAL CASE 1: see Note [Special case for non-recursive function bindings]
tcMonoBinds :: RecFlag
-> TcSigFun
-> LetBndrSpec
-> [LHsBind GhcRn]
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
tcMonoBinds RecFlag
is_rec TcSigFun
sig_fn LetBndrSpec
no_gen
           [ L SrcSpanAnnA
b_loc (FunBind { fun_id :: forall idL idR. HsBindLR idL idR -> LIdP idL
fun_id = L SrcSpanAnnN
nm_loc Name
name
                              , fun_matches :: forall idL idR. HsBindLR idL idR -> MatchGroup idR (LHsExpr idR)
fun_matches = MatchGroup GhcRn (LHsExpr GhcRn)
matches })]
                             -- Single function binding,
  | RecFlag
NonRecursive <- RecFlag
is_rec   -- ...binder isn't mentioned in RHS
  , Maybe TcSigInfo
Nothing <- TcSigFun
sig_fn Name
name   -- ...with no type signature
  = SrcSpanAnnA
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
forall ann a. SrcSpanAnn' ann -> TcRn a -> TcRn a
setSrcSpanA SrcSpanAnnA
b_loc    (TcM (LHsBinds GhcTc, [MonoBindInfo])
 -> TcM (LHsBinds GhcTc, [MonoBindInfo]))
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
forall a b. (a -> b) -> a -> b
$
    do  { ((HsWrapper
co_fn, MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))
matches'), TcId
mono_id, Kind
_) <- (((HsWrapper,
   MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
  TcId, Kind)
 -> IOEnv
      (Env TcGblEnv TcLclEnv)
      ((HsWrapper,
        MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
       TcId, Kind))
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ((HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
      TcId, Kind)
forall a env. (a -> IOEnv env a) -> IOEnv env a
fixM ((((HsWrapper,
    MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
   TcId, Kind)
  -> IOEnv
       (Env TcGblEnv TcLclEnv)
       ((HsWrapper,
         MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
        TcId, Kind))
 -> IOEnv
      (Env TcGblEnv TcLclEnv)
      ((HsWrapper,
        MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
       TcId, Kind))
-> (((HsWrapper,
      MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
     TcId, Kind)
    -> IOEnv
         (Env TcGblEnv TcLclEnv)
         ((HsWrapper,
           MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
          TcId, Kind))
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ((HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
      TcId, Kind)
forall a b. (a -> b) -> a -> b
$ \ ~((HsWrapper,
 MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)))
_, TcId
_, Kind
rhs_ty) ->
                                          -- See Note [fixM for rhs_ty in tcMonoBinds]
            do  { TcId
mono_id <- LetBndrSpec
-> Name -> Kind -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TcId
newLetBndr LetBndrSpec
no_gen Name
name Kind
Many Kind
rhs_ty
                ; ((HsWrapper,
 MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)))
matches', Kind
rhs_ty')
                    <- (ExpSigmaType
 -> TcM
      (HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
-> TcM
     ((HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
      Kind)
forall a. (ExpSigmaType -> TcM a) -> TcM (a, Kind)
tcInfer ((ExpSigmaType
  -> TcM
       (HsWrapper,
        MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
 -> TcM
      ((HsWrapper,
        MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
       Kind))
-> (ExpSigmaType
    -> TcM
         (HsWrapper,
          MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
-> TcM
     ((HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
      Kind)
forall a b. (a -> b) -> a -> b
$ \ ExpSigmaType
exp_ty ->
                       [TcBinder]
-> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
-> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
forall a. [TcBinder] -> TcM a -> TcM a
tcExtendBinderStack [Name -> ExpSigmaType -> TopLevelFlag -> TcBinder
TcIdBndr_ExpType Name
name ExpSigmaType
exp_ty TopLevelFlag
NotTopLevel] (TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
 -> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc)))
-> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
-> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
forall a b. (a -> b) -> a -> b
$
                          -- We extend the error context even for a non-recursive
                          -- function so that in type error messages we show the
                          -- type of the thing whose rhs we are type checking
                       GenLocated SrcSpanAnnN TcId
-> MatchGroup GhcRn (LHsExpr GhcRn)
-> ExpSigmaType
-> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
tcMatchesFun (SrcSpanAnnN -> TcId -> GenLocated SrcSpanAnnN TcId
forall l e. l -> e -> GenLocated l e
L SrcSpanAnnN
nm_loc TcId
mono_id) MatchGroup GhcRn (LHsExpr GhcRn)
matches ExpSigmaType
exp_ty
                ; ((HsWrapper,
  MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
 TcId, Kind)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ((HsWrapper,
       MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))),
      TcId, Kind)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ((HsWrapper,
 MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)))
matches', TcId
mono_id, Kind
rhs_ty')
                }

        ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
 [MonoBindInfo])
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
      [MonoBindInfo])
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a. a -> Bag a
unitBag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
 -> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))
-> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a b. (a -> b) -> a -> b
$ SrcSpanAnnA
-> HsBindLR GhcTc GhcTc
-> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
forall l e. l -> e -> GenLocated l e
L SrcSpanAnnA
b_loc (HsBindLR GhcTc GhcTc
 -> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
-> HsBindLR GhcTc GhcTc
-> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
forall a b. (a -> b) -> a -> b
$
                     FunBind { fun_id :: LIdP GhcTc
fun_id = SrcSpanAnnN -> TcId -> GenLocated SrcSpanAnnN TcId
forall l e. l -> e -> GenLocated l e
L SrcSpanAnnN
nm_loc TcId
mono_id,
                               fun_matches :: MatchGroup GhcTc (LHsExpr GhcTc)
fun_matches = MatchGroup GhcTc (LHsExpr GhcTc)
MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))
matches',
                               fun_ext :: XFunBind GhcTc GhcTc
fun_ext = XFunBind GhcTc GhcTc
HsWrapper
co_fn, fun_tick :: [CoreTickish]
fun_tick = [] },
                  [MBI { mbi_poly_name :: Name
mbi_poly_name = Name
name
                       , mbi_sig :: Maybe TcIdSigInst
mbi_sig       = Maybe TcIdSigInst
forall a. Maybe a
Nothing
                       , mbi_mono_id :: TcId
mbi_mono_id   = TcId
mono_id }]) }

-- SPECIAL CASE 2: see Note [Special case for non-recursive pattern bindings]
tcMonoBinds RecFlag
is_rec TcSigFun
sig_fn LetBndrSpec
no_gen
           [L SrcSpanAnnA
b_loc (PatBind { pat_lhs :: forall idL idR. HsBindLR idL idR -> LPat idL
pat_lhs = LPat GhcRn
pat, pat_rhs :: forall idL idR. HsBindLR idL idR -> GRHSs idR (LHsExpr idR)
pat_rhs = GRHSs GhcRn (LHsExpr GhcRn)
grhss })]
  | RecFlag
NonRecursive <- RecFlag
is_rec   -- ...binder isn't mentioned in RHS
  , (Name -> Bool) -> [Name] -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
all (Maybe TcSigInfo -> Bool
forall a. Maybe a -> Bool
isNothing (Maybe TcSigInfo -> Bool) -> TcSigFun -> Name -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. TcSigFun
sig_fn) [IdP GhcRn]
[Name]
bndrs
  = SDoc
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
forall a. SDoc -> TcM a -> TcM a
addErrCtxt (LPat GhcRn -> GRHSs GhcRn (LHsExpr GhcRn) -> SDoc
forall (p :: Pass).
OutputableBndrId p =>
LPat (GhcPass p) -> GRHSs GhcRn (LHsExpr GhcRn) -> SDoc
patMonoBindsCtxt LPat GhcRn
pat GRHSs GhcRn (LHsExpr GhcRn)
grhss) (TcM (LHsBinds GhcTc, [MonoBindInfo])
 -> TcM (LHsBinds GhcTc, [MonoBindInfo]))
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
-> TcM (LHsBinds GhcTc, [MonoBindInfo])
forall a b. (a -> b) -> a -> b
$
    do { (GRHSs GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))
grhss', Kind
pat_ty) <- (ExpSigmaType
 -> TcM (GRHSs GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
-> TcM (GRHSs GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)), Kind)
forall a. (ExpSigmaType -> TcM a) -> TcM (a, Kind)
tcInfer ((ExpSigmaType
  -> TcM (GRHSs GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
 -> TcM (GRHSs GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)), Kind))
-> (ExpSigmaType
    -> TcM (GRHSs GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))))
-> TcM (GRHSs GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc)), Kind)
forall a b. (a -> b) -> a -> b
$ \ ExpSigmaType
exp_ty ->
                             GRHSs GhcRn (LHsExpr GhcRn)
-> ExpSigmaType -> TcM (GRHSs GhcTc (LHsExpr GhcTc))
tcGRHSsPat GRHSs GhcRn (LHsExpr GhcRn)
grhss ExpSigmaType
exp_ty

       ; let exp_pat_ty :: Scaled ExpSigmaTypeFRR
             exp_pat_ty :: Scaled ExpSigmaType
exp_pat_ty = ExpSigmaType -> Scaled ExpSigmaType
forall a. a -> Scaled a
unrestricted (Kind -> ExpSigmaType
mkCheckExpType Kind
pat_ty)
       ; (GenLocated SrcSpanAnnA (Pat GhcTc)
pat', [MonoBindInfo]
mbis) <- (Name -> Maybe TcId)
-> LetBndrSpec
-> LPat GhcRn
-> Scaled ExpSigmaType
-> TcM [MonoBindInfo]
-> TcM (LPat GhcTc, [MonoBindInfo])
forall a.
(Name -> Maybe TcId)
-> LetBndrSpec
-> LPat GhcRn
-> Scaled ExpSigmaType
-> TcM a
-> TcM (LPat GhcTc, a)
tcLetPat (Maybe TcId -> Name -> Maybe TcId
forall a b. a -> b -> a
const Maybe TcId
forall a. Maybe a
Nothing) LetBndrSpec
no_gen LPat GhcRn
pat Scaled ExpSigmaType
exp_pat_ty (TcM [MonoBindInfo] -> TcM (LPat GhcTc, [MonoBindInfo]))
-> TcM [MonoBindInfo] -> TcM (LPat GhcTc, [MonoBindInfo])
forall a b. (a -> b) -> a -> b
$
                         (Name -> IOEnv (Env TcGblEnv TcLclEnv) MonoBindInfo)
-> [Name] -> TcM [MonoBindInfo]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM Name -> IOEnv (Env TcGblEnv TcLclEnv) MonoBindInfo
lookupMBI [IdP GhcRn]
[Name]
bndrs

       ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
 [MonoBindInfo])
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
      [MonoBindInfo])
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ( GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a. a -> Bag a
unitBag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
 -> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))
-> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a b. (a -> b) -> a -> b
$ SrcSpanAnnA
-> HsBindLR GhcTc GhcTc
-> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
forall l e. l -> e -> GenLocated l e
L SrcSpanAnnA
b_loc (HsBindLR GhcTc GhcTc
 -> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
-> HsBindLR GhcTc GhcTc
-> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
forall a b. (a -> b) -> a -> b
$
                     PatBind { pat_lhs :: LPat GhcTc
pat_lhs = LPat GhcTc
GenLocated SrcSpanAnnA (Pat GhcTc)
pat', pat_rhs :: GRHSs GhcTc (LHsExpr GhcTc)
pat_rhs = GRHSs GhcTc (LHsExpr GhcTc)
GRHSs GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))
grhss'
                             , pat_ext :: XPatBind GhcTc GhcTc
pat_ext = XPatBind GhcTc GhcTc
Kind
pat_ty, pat_ticks :: ([CoreTickish], [[CoreTickish]])
pat_ticks = ([],[]) }

                , [MonoBindInfo]
mbis ) }
  where
    bndrs :: [IdP GhcRn]
bndrs = CollectFlag GhcRn -> LPat GhcRn -> [IdP GhcRn]
forall p. CollectPass p => CollectFlag p -> LPat p -> [IdP p]
collectPatBinders CollectFlag GhcRn
forall p. CollectFlag p
CollNoDictBinders LPat GhcRn
pat

-- GENERAL CASE
tcMonoBinds RecFlag
_ TcSigFun
sig_fn LetBndrSpec
no_gen [LHsBind GhcRn]
binds
  = do  { [GenLocated SrcSpanAnnA TcMonoBind]
tc_binds <- (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
 -> IOEnv
      (Env TcGblEnv TcLclEnv) (GenLocated SrcSpanAnnA TcMonoBind))
-> [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
-> IOEnv
     (Env TcGblEnv TcLclEnv) [GenLocated SrcSpanAnnA TcMonoBind]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM ((HsBindLR GhcRn GhcRn -> TcM TcMonoBind)
-> GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
-> IOEnv
     (Env TcGblEnv TcLclEnv) (GenLocated SrcSpanAnnA TcMonoBind)
forall a b ann.
(a -> TcM b)
-> GenLocated (SrcSpanAnn' ann) a
-> TcRn (GenLocated (SrcSpanAnn' ann) b)
wrapLocMA (TcSigFun -> LetBndrSpec -> HsBindLR GhcRn GhcRn -> TcM TcMonoBind
tcLhs TcSigFun
sig_fn LetBndrSpec
no_gen)) [LHsBind GhcRn]
[GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
binds

        -- Bring the monomorphic Ids, into scope for the RHSs
        ; let mono_infos :: [MonoBindInfo]
mono_infos = [GenLocated SrcSpanAnnA TcMonoBind] -> [MonoBindInfo]
getMonoBindInfo [GenLocated SrcSpanAnnA TcMonoBind]
tc_binds
              rhs_id_env :: [(Name, TcId)]
rhs_id_env = [ (Name
name, TcId
mono_id)
                           | MBI { mbi_poly_name :: MonoBindInfo -> Name
mbi_poly_name = Name
name
                                 , mbi_sig :: MonoBindInfo -> Maybe TcIdSigInst
mbi_sig       = Maybe TcIdSigInst
mb_sig
                                 , mbi_mono_id :: MonoBindInfo -> TcId
mbi_mono_id   = TcId
mono_id } <- [MonoBindInfo]
mono_infos
                           , case Maybe TcIdSigInst
mb_sig of
                               Just TcIdSigInst
sig -> TcIdSigInst -> Bool
isPartialSig TcIdSigInst
sig
                               Maybe TcIdSigInst
Nothing  -> Bool
True ]
                -- A monomorphic binding for each term variable that lacks
                -- a complete type sig.  (Ones with a sig are already in scope.)

        ; String -> SDoc -> TcRn ()
traceTc String
"tcMonoBinds" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
forall a b. (a -> b) -> a -> b
$ [SDoc] -> SDoc
vcat [ Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
n SDoc -> SDoc -> SDoc
<+> TcId -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcId
id SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TcId -> Kind
idType TcId
id)
                                       | (Name
n,TcId
id) <- [(Name, TcId)]
rhs_id_env]
        ; [GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)]
binds' <- [(Name, TcId)]
-> TcM [GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)]
-> TcM [GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)]
forall a. [(Name, TcId)] -> TcM a -> TcM a
tcExtendRecIds [(Name, TcId)]
rhs_id_env (TcM [GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)]
 -> TcM [GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)])
-> TcM [GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)]
-> TcM [GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)]
forall a b. (a -> b) -> a -> b
$
                    (GenLocated SrcSpanAnnA TcMonoBind
 -> IOEnv
      (Env TcGblEnv TcLclEnv)
      (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))
-> [GenLocated SrcSpanAnnA TcMonoBind]
-> TcM [GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM ((TcMonoBind -> TcM (HsBindLR GhcTc GhcTc))
-> GenLocated SrcSpanAnnA TcMonoBind
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a b ann.
(a -> TcM b)
-> GenLocated (SrcSpanAnn' ann) a
-> TcRn (GenLocated (SrcSpanAnn' ann) b)
wrapLocMA TcMonoBind -> TcM (HsBindLR GhcTc GhcTc)
tcRhs) [GenLocated SrcSpanAnnA TcMonoBind]
tc_binds

        ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
 [MonoBindInfo])
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)),
      [MonoBindInfo])
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ([GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)]
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
forall a. [a] -> Bag a
listToBag [GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)]
binds', [MonoBindInfo]
mono_infos) }

{- Note [Special case for non-recursive function bindings]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In the special case of
* A non-recursive FunBind
* With no type signature
we infer the type of the right hand side first (it may have a
higher-rank type) and *then* make the monomorphic Id for the LHS e.g.
   f = \(x::forall a. a->a) -> <body>

We want to infer a higher-rank type for f

Note [Special case for non-recursive pattern bindings]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In the special case of
* A pattern binding
* With no type signature for any of the binders
we can /infer/ the type of the RHS, and /check/ the pattern
against that type.  For example (#18323)

  ids :: [forall a. a -> a]
  combine :: (forall a . [a] -> a) -> [forall a. a -> a]
          -> ((forall a . [a] -> a), [forall a. a -> a])

  (x,y) = combine head ids

with -XImpredicativeTypes we can infer a good type for
(combine head ids), and use that to tell us the polymorphic
types of x and y.

We don't need to check -XImpredicativeTypes beucase without it
these types like [forall a. a->a] are illegal anyway, so this
special case code only really has an effect if -XImpredicativeTypes
is on.  Small exception:
  (x) = e
is currently treated as a pattern binding so, even absent
-XImpredicativeTypes, we will get a small improvement in behaviour.
But I don't think it's worth an extension flag.

Why do we require no type signatures on /any/ of the binders?
Consider
   x :: forall a. a->a
   y :: forall a. a->a
   (x,y) = (id,id)

Here we should /check/ the RHS with expected type
  (forall a. a->a, forall a. a->a).

If we have no signatures, we can the approach of this Note
to /infer/ the type of the RHS.

But what if we have some signatures, but not all? Say this:
  p :: forall a. a->a
  (p,q) = (id,  (\(x::forall b. b->b). x True))

Here we want to push p's signature inwards, i.e. /checking/, to
correctly elaborate 'id'. But we want to /infer/ q's higher rank
type.  There seems to be no way to do this.  So currently we only
switch to inference when we have no signature for any of the binders.

Note [fixM for rhs_ty in tcMonoBinds]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In order to create mono_id we need rhs_ty but we don't have it yet,
we only get it from tcMatchesFun later (which needs mono_id to put
into HsMatchContext for pretty printing). To solve this, create
a thunk of rhs_ty with fixM that we fill in later.

This is fine only because neither newLetBndr or tcMatchesFun look
at the varType field of the Id. tcMatchesFun only looks at idName
of mono_id.

Also see #20415 for the bigger picture of why tcMatchesFun needs
mono_id in the first place.
-}


------------------------
-- tcLhs typechecks the LHS of the bindings, to construct the environment in which
-- we typecheck the RHSs.  Basically what we are doing is this: for each binder:
--      if there's a signature for it, use the instantiated signature type
--      otherwise invent a type variable
-- You see that quite directly in the FunBind case.
--
-- But there's a complication for pattern bindings:
--      data T = MkT (forall a. a->a)
--      MkT f = e
-- Here we can guess a type variable for the entire LHS (which will be refined to T)
-- but we want to get (f::forall a. a->a) as the RHS environment.
-- The simplest way to do this is to typecheck the pattern, and then look up the
-- bound mono-ids.  Then we want to retain the typechecked pattern to avoid re-doing
-- it; hence the TcMonoBind data type in which the LHS is done but the RHS isn't

data TcMonoBind         -- Half completed; LHS done, RHS not done
  = TcFunBind  MonoBindInfo  SrcSpan (MatchGroup GhcRn (LHsExpr GhcRn))
  | TcPatBind [MonoBindInfo] (LPat GhcTc) (GRHSs GhcRn (LHsExpr GhcRn))
              TcSigmaTypeFRR

tcLhs :: TcSigFun -> LetBndrSpec -> HsBind GhcRn -> TcM TcMonoBind
-- Only called with plan InferGen (LetBndrSpec = LetLclBndr)
--                    or NoGen    (LetBndrSpec = LetGblBndr)
-- CheckGen is used only for functions with a complete type signature,
--          and tcPolyCheck doesn't use tcMonoBinds at all

tcLhs :: TcSigFun -> LetBndrSpec -> HsBindLR GhcRn GhcRn -> TcM TcMonoBind
tcLhs TcSigFun
sig_fn LetBndrSpec
no_gen (FunBind { fun_id :: forall idL idR. HsBindLR idL idR -> LIdP idL
fun_id = L SrcSpanAnnN
nm_loc Name
name
                             , fun_matches :: forall idL idR. HsBindLR idL idR -> MatchGroup idR (LHsExpr idR)
fun_matches = MatchGroup GhcRn (LHsExpr GhcRn)
matches })
  | Just (TcIdSig TcIdSigInfo
sig) <- TcSigFun
sig_fn Name
name
  = -- There is a type signature.
    -- It must be partial; if complete we'd be in tcPolyCheck!
    --    e.g.   f :: _ -> _
    --           f x = ...g...
    --           Just g = ...f...
    -- Hence always typechecked with InferGen
    do { MonoBindInfo
mono_info <- LetBndrSpec
-> (Name, TcIdSigInfo)
-> IOEnv (Env TcGblEnv TcLclEnv) MonoBindInfo
tcLhsSigId LetBndrSpec
no_gen (Name
name, TcIdSigInfo
sig)
       ; TcMonoBind -> TcM TcMonoBind
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (MonoBindInfo
-> SrcSpan -> MatchGroup GhcRn (LHsExpr GhcRn) -> TcMonoBind
TcFunBind MonoBindInfo
mono_info (SrcSpanAnnN -> SrcSpan
forall a. SrcSpanAnn' a -> SrcSpan
locA SrcSpanAnnN
nm_loc) MatchGroup GhcRn (LHsExpr GhcRn)
matches) }

  | Bool
otherwise  -- No type signature
  = do { Kind
mono_ty <- TcM Kind
newOpenFlexiTyVarTy
       ; TcId
mono_id <- LetBndrSpec
-> Name -> Kind -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TcId
newLetBndr LetBndrSpec
no_gen Name
name Kind
Many Kind
mono_ty
          -- This ^ generates a binder with Many multiplicity because all
          -- let/where-binders are unrestricted. When we introduce linear let
          -- binders, we will need to retrieve the multiplicity information.
       ; let mono_info :: MonoBindInfo
mono_info = MBI { mbi_poly_name :: Name
mbi_poly_name = Name
name
                             , mbi_sig :: Maybe TcIdSigInst
mbi_sig       = Maybe TcIdSigInst
forall a. Maybe a
Nothing
                             , mbi_mono_id :: TcId
mbi_mono_id   = TcId
mono_id }
       ; TcMonoBind -> TcM TcMonoBind
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (MonoBindInfo
-> SrcSpan -> MatchGroup GhcRn (LHsExpr GhcRn) -> TcMonoBind
TcFunBind MonoBindInfo
mono_info (SrcSpanAnnN -> SrcSpan
forall a. SrcSpanAnn' a -> SrcSpan
locA SrcSpanAnnN
nm_loc) MatchGroup GhcRn (LHsExpr GhcRn)
matches) }

tcLhs TcSigFun
sig_fn LetBndrSpec
no_gen (PatBind { pat_lhs :: forall idL idR. HsBindLR idL idR -> LPat idL
pat_lhs = LPat GhcRn
pat, pat_rhs :: forall idL idR. HsBindLR idL idR -> GRHSs idR (LHsExpr idR)
pat_rhs = GRHSs GhcRn (LHsExpr GhcRn)
grhss })
  = -- See Note [Typechecking pattern bindings]
    do  { [MonoBindInfo]
sig_mbis <- ((Name, TcIdSigInfo) -> IOEnv (Env TcGblEnv TcLclEnv) MonoBindInfo)
-> [(Name, TcIdSigInfo)] -> TcM [MonoBindInfo]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM (LetBndrSpec
-> (Name, TcIdSigInfo)
-> IOEnv (Env TcGblEnv TcLclEnv) MonoBindInfo
tcLhsSigId LetBndrSpec
no_gen) [(Name, TcIdSigInfo)]
sig_names

        ; let inst_sig_fun :: Name -> Maybe TcId
inst_sig_fun = NameEnv TcId -> Name -> Maybe TcId
forall a. NameEnv a -> Name -> Maybe a
lookupNameEnv (NameEnv TcId -> Name -> Maybe TcId)
-> NameEnv TcId -> Name -> Maybe TcId
forall a b. (a -> b) -> a -> b
$ [(Name, TcId)] -> NameEnv TcId
forall a. [(Name, a)] -> NameEnv a
mkNameEnv ([(Name, TcId)] -> NameEnv TcId) -> [(Name, TcId)] -> NameEnv TcId
forall a b. (a -> b) -> a -> b
$
                             [ (MonoBindInfo -> Name
mbi_poly_name MonoBindInfo
mbi, MonoBindInfo -> TcId
mbi_mono_id MonoBindInfo
mbi)
                             | MonoBindInfo
mbi <- [MonoBindInfo]
sig_mbis ]

            -- See Note [Existentials in pattern bindings]
        ; ((GenLocated SrcSpanAnnA (Pat GhcTc)
pat', [MonoBindInfo]
nosig_mbis), Kind
pat_ty)
            <- SDoc
-> TcM ((GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]), Kind)
-> TcM ((GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]), Kind)
forall a. SDoc -> TcM a -> TcM a
addErrCtxt (LPat GhcRn -> GRHSs GhcRn (LHsExpr GhcRn) -> SDoc
forall (p :: Pass).
OutputableBndrId p =>
LPat (GhcPass p) -> GRHSs GhcRn (LHsExpr GhcRn) -> SDoc
patMonoBindsCtxt LPat GhcRn
pat GRHSs GhcRn (LHsExpr GhcRn)
grhss) (TcM ((GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]), Kind)
 -> TcM
      ((GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]), Kind))
-> TcM ((GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]), Kind)
-> TcM ((GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]), Kind)
forall a b. (a -> b) -> a -> b
$
               FixedRuntimeRepContext
-> (ExpSigmaType
    -> IOEnv
         (Env TcGblEnv TcLclEnv)
         (GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]))
-> TcM ((GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]), Kind)
forall a.
FixedRuntimeRepContext -> (ExpSigmaType -> TcM a) -> TcM (a, Kind)
tcInferFRR FixedRuntimeRepContext
FRRPatBind ((ExpSigmaType
  -> IOEnv
       (Env TcGblEnv TcLclEnv)
       (GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]))
 -> TcM
      ((GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]), Kind))
-> (ExpSigmaType
    -> IOEnv
         (Env TcGblEnv TcLclEnv)
         (GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]))
-> TcM ((GenLocated SrcSpanAnnA (Pat GhcTc), [MonoBindInfo]), Kind)
forall a b. (a -> b) -> a -> b
$ \ ExpSigmaType
exp_ty ->
               (Name -> Maybe TcId)
-> LetBndrSpec
-> LPat GhcRn
-> Scaled ExpSigmaType
-> TcM [MonoBindInfo]
-> TcM (LPat GhcTc, [MonoBindInfo])
forall a.
(Name -> Maybe TcId)
-> LetBndrSpec
-> LPat GhcRn
-> Scaled ExpSigmaType
-> TcM a
-> TcM (LPat GhcTc, a)
tcLetPat Name -> Maybe TcId
inst_sig_fun LetBndrSpec
no_gen LPat GhcRn
pat (ExpSigmaType -> Scaled ExpSigmaType
forall a. a -> Scaled a
unrestricted ExpSigmaType
exp_ty) (TcM [MonoBindInfo] -> TcM (LPat GhcTc, [MonoBindInfo]))
-> TcM [MonoBindInfo] -> TcM (LPat GhcTc, [MonoBindInfo])
forall a b. (a -> b) -> a -> b
$
                 -- The above inferred type get an unrestricted multiplicity. It may be
                 -- worth it to try and find a finer-grained multiplicity here
                 -- if examples warrant it.
               (Name -> IOEnv (Env TcGblEnv TcLclEnv) MonoBindInfo)
-> [Name] -> TcM [MonoBindInfo]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM Name -> IOEnv (Env TcGblEnv TcLclEnv) MonoBindInfo
lookupMBI [Name]
nosig_names

        ; let mbis :: [MonoBindInfo]
mbis = [MonoBindInfo]
sig_mbis [MonoBindInfo] -> [MonoBindInfo] -> [MonoBindInfo]
forall a. [a] -> [a] -> [a]
++ [MonoBindInfo]
nosig_mbis

        ; String -> SDoc -> TcRn ()
traceTc String
"tcLhs" ([SDoc] -> SDoc
vcat [ TcId -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcId
id SDoc -> SDoc -> SDoc
<+> SDoc
dcolon SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TcId -> Kind
idType TcId
id)
                                | MonoBindInfo
mbi <- [MonoBindInfo]
mbis, let id :: TcId
id = MonoBindInfo -> TcId
mbi_mono_id MonoBindInfo
mbi ]
                           SDoc -> SDoc -> SDoc
$$ LetBndrSpec -> SDoc
forall a. Outputable a => a -> SDoc
ppr LetBndrSpec
no_gen)

        ; TcMonoBind -> TcM TcMonoBind
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ([MonoBindInfo]
-> LPat GhcTc -> GRHSs GhcRn (LHsExpr GhcRn) -> Kind -> TcMonoBind
TcPatBind [MonoBindInfo]
mbis LPat GhcTc
GenLocated SrcSpanAnnA (Pat GhcTc)
pat' GRHSs GhcRn (LHsExpr GhcRn)
grhss Kind
pat_ty) }
  where
    bndr_names :: [IdP GhcRn]
bndr_names = CollectFlag GhcRn -> LPat GhcRn -> [IdP GhcRn]
forall p. CollectPass p => CollectFlag p -> LPat p -> [IdP p]
collectPatBinders CollectFlag GhcRn
forall p. CollectFlag p
CollNoDictBinders LPat GhcRn
pat
    ([Name]
nosig_names, [(Name, TcIdSigInfo)]
sig_names) = (Name -> Either Name (Name, TcIdSigInfo))
-> [Name] -> ([Name], [(Name, TcIdSigInfo)])
forall a b c. (a -> Either b c) -> [a] -> ([b], [c])
partitionWith Name -> Either Name (Name, TcIdSigInfo)
find_sig [IdP GhcRn]
[Name]
bndr_names

    find_sig :: Name -> Either Name (Name, TcIdSigInfo)
    find_sig :: Name -> Either Name (Name, TcIdSigInfo)
find_sig Name
name = case TcSigFun
sig_fn Name
name of
                      Just (TcIdSig TcIdSigInfo
sig) -> (Name, TcIdSigInfo) -> Either Name (Name, TcIdSigInfo)
forall a b. b -> Either a b
Right (Name
name, TcIdSigInfo
sig)
                      Maybe TcSigInfo
_                  -> Name -> Either Name (Name, TcIdSigInfo)
forall a b. a -> Either a b
Left Name
name

tcLhs TcSigFun
_ LetBndrSpec
_ HsBindLR GhcRn GhcRn
other_bind = String -> SDoc -> TcM TcMonoBind
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"tcLhs" (HsBindLR GhcRn GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr HsBindLR GhcRn GhcRn
other_bind)
        -- AbsBind, VarBind impossible

lookupMBI :: Name -> TcM MonoBindInfo
-- After typechecking the pattern, look up the binder
-- names that lack a signature, which the pattern has brought
-- into scope.
lookupMBI :: Name -> IOEnv (Env TcGblEnv TcLclEnv) MonoBindInfo
lookupMBI Name
name
  = do { TcId
mono_id <- Name -> IOEnv (Env TcGblEnv TcLclEnv) TcId
tcLookupId Name
name
       ; MonoBindInfo -> IOEnv (Env TcGblEnv TcLclEnv) MonoBindInfo
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (MBI { mbi_poly_name :: Name
mbi_poly_name = Name
name
                     , mbi_sig :: Maybe TcIdSigInst
mbi_sig       = Maybe TcIdSigInst
forall a. Maybe a
Nothing
                     , mbi_mono_id :: TcId
mbi_mono_id   = TcId
mono_id }) }

-------------------
tcLhsSigId :: LetBndrSpec -> (Name, TcIdSigInfo) -> TcM MonoBindInfo
tcLhsSigId :: LetBndrSpec
-> (Name, TcIdSigInfo)
-> IOEnv (Env TcGblEnv TcLclEnv) MonoBindInfo
tcLhsSigId LetBndrSpec
no_gen (Name
name, TcIdSigInfo
sig)
  = do { TcIdSigInst
inst_sig <- TcIdSigInfo -> TcM TcIdSigInst
tcInstSig TcIdSigInfo
sig
       ; TcId
mono_id <- LetBndrSpec
-> Name -> TcIdSigInst -> IOEnv (Env TcGblEnv TcLclEnv) TcId
newSigLetBndr LetBndrSpec
no_gen Name
name TcIdSigInst
inst_sig
       ; MonoBindInfo -> IOEnv (Env TcGblEnv TcLclEnv) MonoBindInfo
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (MBI { mbi_poly_name :: Name
mbi_poly_name = Name
name
                     , mbi_sig :: Maybe TcIdSigInst
mbi_sig       = TcIdSigInst -> Maybe TcIdSigInst
forall a. a -> Maybe a
Just TcIdSigInst
inst_sig
                     , mbi_mono_id :: TcId
mbi_mono_id   = TcId
mono_id }) }

------------
newSigLetBndr :: LetBndrSpec -> Name -> TcIdSigInst -> TcM TcId
newSigLetBndr :: LetBndrSpec
-> Name -> TcIdSigInst -> IOEnv (Env TcGblEnv TcLclEnv) TcId
newSigLetBndr (LetGblBndr TcPragEnv
prags) Name
name (TISI { sig_inst_sig :: TcIdSigInst -> TcIdSigInfo
sig_inst_sig = TcIdSigInfo
id_sig })
  | CompleteSig { sig_bndr :: TcIdSigInfo -> TcId
sig_bndr = TcId
poly_id } <- TcIdSigInfo
id_sig
  = TcId -> [LSig GhcRn] -> IOEnv (Env TcGblEnv TcLclEnv) TcId
addInlinePrags TcId
poly_id (TcPragEnv -> Name -> [LSig GhcRn]
lookupPragEnv TcPragEnv
prags Name
name)
newSigLetBndr LetBndrSpec
no_gen Name
name (TISI { sig_inst_tau :: TcIdSigInst -> Kind
sig_inst_tau = Kind
tau })
  = LetBndrSpec
-> Name -> Kind -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TcId
newLetBndr LetBndrSpec
no_gen Name
name Kind
Many Kind
tau
    -- Binders with a signature are currently always of multiplicity
    -- Many. Because they come either from toplevel, let, or where
    -- declarations. Which are all unrestricted currently.

-------------------
tcRhs :: TcMonoBind -> TcM (HsBind GhcTc)
tcRhs :: TcMonoBind -> TcM (HsBindLR GhcTc GhcTc)
tcRhs (TcFunBind info :: MonoBindInfo
info@(MBI { mbi_sig :: MonoBindInfo -> Maybe TcIdSigInst
mbi_sig = Maybe TcIdSigInst
mb_sig, mbi_mono_id :: MonoBindInfo -> TcId
mbi_mono_id = TcId
mono_id })
                 SrcSpan
loc MatchGroup GhcRn (LHsExpr GhcRn)
matches)
  = [MonoBindInfo]
-> TcM (HsBindLR GhcTc GhcTc) -> TcM (HsBindLR GhcTc GhcTc)
forall a. [MonoBindInfo] -> TcM a -> TcM a
tcExtendIdBinderStackForRhs [MonoBindInfo
info]  (TcM (HsBindLR GhcTc GhcTc) -> TcM (HsBindLR GhcTc GhcTc))
-> TcM (HsBindLR GhcTc GhcTc) -> TcM (HsBindLR GhcTc GhcTc)
forall a b. (a -> b) -> a -> b
$
    Maybe TcIdSigInst
-> TcM (HsBindLR GhcTc GhcTc) -> TcM (HsBindLR GhcTc GhcTc)
forall a. Maybe TcIdSigInst -> TcM a -> TcM a
tcExtendTyVarEnvForRhs Maybe TcIdSigInst
mb_sig       (TcM (HsBindLR GhcTc GhcTc) -> TcM (HsBindLR GhcTc GhcTc))
-> TcM (HsBindLR GhcTc GhcTc) -> TcM (HsBindLR GhcTc GhcTc)
forall a b. (a -> b) -> a -> b
$
    do  { String -> SDoc -> TcRn ()
traceTc String
"tcRhs: fun bind" (TcId -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcId
mono_id SDoc -> SDoc -> SDoc
$$ Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TcId -> Kind
idType TcId
mono_id))
        ; (HsWrapper
co_fn, MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))
matches') <- GenLocated SrcSpanAnnN TcId
-> MatchGroup GhcRn (LHsExpr GhcRn)
-> ExpSigmaType
-> TcRn (HsWrapper, MatchGroup GhcTc (LHsExpr GhcTc))
tcMatchesFun (SrcSpanAnnN -> TcId -> GenLocated SrcSpanAnnN TcId
forall l e. l -> e -> GenLocated l e
L (SrcSpan -> SrcSpanAnnN
forall ann. SrcSpan -> SrcAnn ann
noAnnSrcSpan SrcSpan
loc) TcId
mono_id)
                                 MatchGroup GhcRn (LHsExpr GhcRn)
matches (Kind -> ExpSigmaType
mkCheckExpType (Kind -> ExpSigmaType) -> Kind -> ExpSigmaType
forall a b. (a -> b) -> a -> b
$ TcId -> Kind
idType TcId
mono_id)
        ; HsBindLR GhcTc GhcTc -> TcM (HsBindLR GhcTc GhcTc)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ( FunBind { fun_id :: LIdP GhcTc
fun_id = SrcSpanAnnN -> TcId -> GenLocated SrcSpanAnnN TcId
forall l e. l -> e -> GenLocated l e
L (SrcSpan -> SrcSpanAnnN
forall ann. SrcSpan -> SrcAnn ann
noAnnSrcSpan SrcSpan
loc) TcId
mono_id
                           , fun_matches :: MatchGroup GhcTc (LHsExpr GhcTc)
fun_matches = MatchGroup GhcTc (LHsExpr GhcTc)
MatchGroup GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))
matches'
                           , fun_ext :: XFunBind GhcTc GhcTc
fun_ext = XFunBind GhcTc GhcTc
HsWrapper
co_fn
                           , fun_tick :: [CoreTickish]
fun_tick = [] } ) }

tcRhs (TcPatBind [MonoBindInfo]
infos LPat GhcTc
pat' GRHSs GhcRn (LHsExpr GhcRn)
grhss Kind
pat_ty)
  = -- When we are doing pattern bindings we *don't* bring any scoped
    -- type variables into scope unlike function bindings
    -- Wny not?  They are not completely rigid.
    -- That's why we have the special case for a single FunBind in tcMonoBinds
    [MonoBindInfo]
-> TcM (HsBindLR GhcTc GhcTc) -> TcM (HsBindLR GhcTc GhcTc)
forall a. [MonoBindInfo] -> TcM a -> TcM a
tcExtendIdBinderStackForRhs [MonoBindInfo]
infos        (TcM (HsBindLR GhcTc GhcTc) -> TcM (HsBindLR GhcTc GhcTc))
-> TcM (HsBindLR GhcTc GhcTc) -> TcM (HsBindLR GhcTc GhcTc)
forall a b. (a -> b) -> a -> b
$
    do  { String -> SDoc -> TcRn ()
traceTc String
"tcRhs: pat bind" (GenLocated SrcSpanAnnA (Pat GhcTc) -> SDoc
forall a. Outputable a => a -> SDoc
ppr LPat GhcTc
GenLocated SrcSpanAnnA (Pat GhcTc)
pat' SDoc -> SDoc -> SDoc
$$ Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr Kind
pat_ty)
        ; GRHSs GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))
grhss' <- SDoc
-> TcM (GRHSs GhcTc (LHsExpr GhcTc))
-> TcM (GRHSs GhcTc (LHsExpr GhcTc))
forall a. SDoc -> TcM a -> TcM a
addErrCtxt (LPat GhcTc -> GRHSs GhcRn (LHsExpr GhcRn) -> SDoc
forall (p :: Pass).
OutputableBndrId p =>
LPat (GhcPass p) -> GRHSs GhcRn (LHsExpr GhcRn) -> SDoc
patMonoBindsCtxt LPat GhcTc
pat' GRHSs GhcRn (LHsExpr GhcRn)
grhss) (TcM (GRHSs GhcTc (LHsExpr GhcTc))
 -> TcM (GRHSs GhcTc (LHsExpr GhcTc)))
-> TcM (GRHSs GhcTc (LHsExpr GhcTc))
-> TcM (GRHSs GhcTc (LHsExpr GhcTc))
forall a b. (a -> b) -> a -> b
$
                    GRHSs GhcRn (LHsExpr GhcRn)
-> ExpSigmaType -> TcM (GRHSs GhcTc (LHsExpr GhcTc))
tcGRHSsPat GRHSs GhcRn (LHsExpr GhcRn)
grhss (Kind -> ExpSigmaType
mkCheckExpType Kind
pat_ty)

        ; HsBindLR GhcTc GhcTc -> TcM (HsBindLR GhcTc GhcTc)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return ( PatBind { pat_lhs :: LPat GhcTc
pat_lhs = LPat GhcTc
pat', pat_rhs :: GRHSs GhcTc (LHsExpr GhcTc)
pat_rhs = GRHSs GhcTc (LHsExpr GhcTc)
GRHSs GhcTc (GenLocated SrcSpanAnnA (HsExpr GhcTc))
grhss'
                           , pat_ext :: XPatBind GhcTc GhcTc
pat_ext = XPatBind GhcTc GhcTc
Kind
pat_ty
                           , pat_ticks :: ([CoreTickish], [[CoreTickish]])
pat_ticks = ([],[]) } )}

tcExtendTyVarEnvForRhs :: Maybe TcIdSigInst -> TcM a -> TcM a
tcExtendTyVarEnvForRhs :: forall a. Maybe TcIdSigInst -> TcM a -> TcM a
tcExtendTyVarEnvForRhs Maybe TcIdSigInst
Nothing TcM a
thing_inside
  = TcM a
thing_inside
tcExtendTyVarEnvForRhs (Just TcIdSigInst
sig) TcM a
thing_inside
  = TcIdSigInst -> TcM a -> TcM a
forall a. TcIdSigInst -> TcM a -> TcM a
tcExtendTyVarEnvFromSig TcIdSigInst
sig TcM a
thing_inside

tcExtendTyVarEnvFromSig :: TcIdSigInst -> TcM a -> TcM a
tcExtendTyVarEnvFromSig :: forall a. TcIdSigInst -> TcM a -> TcM a
tcExtendTyVarEnvFromSig TcIdSigInst
sig_inst TcM a
thing_inside
  | TISI { sig_inst_skols :: TcIdSigInst -> [(Name, InvisTVBinder)]
sig_inst_skols = [(Name, InvisTVBinder)]
skol_prs, sig_inst_wcs :: TcIdSigInst -> [(Name, TcId)]
sig_inst_wcs = [(Name, TcId)]
wcs } <- TcIdSigInst
sig_inst
  = [(Name, TcId)] -> TcM a -> TcM a
forall a. [(Name, TcId)] -> TcM a -> TcM a
tcExtendNameTyVarEnv [(Name, TcId)]
wcs (TcM a -> TcM a) -> TcM a -> TcM a
forall a b. (a -> b) -> a -> b
$
    [(Name, TcId)] -> TcM a -> TcM a
forall a. [(Name, TcId)] -> TcM a -> TcM a
tcExtendNameTyVarEnv ((InvisTVBinder -> TcId)
-> [(Name, InvisTVBinder)] -> [(Name, TcId)]
forall b c a. (b -> c) -> [(a, b)] -> [(a, c)]
mapSnd InvisTVBinder -> TcId
forall tv argf. VarBndr tv argf -> tv
binderVar [(Name, InvisTVBinder)]
skol_prs) (TcM a -> TcM a) -> TcM a -> TcM a
forall a b. (a -> b) -> a -> b
$
    TcM a
thing_inside

tcExtendIdBinderStackForRhs :: [MonoBindInfo] -> TcM a -> TcM a
-- See Note [Relevant bindings and the binder stack]
tcExtendIdBinderStackForRhs :: forall a. [MonoBindInfo] -> TcM a -> TcM a
tcExtendIdBinderStackForRhs [MonoBindInfo]
infos TcM a
thing_inside
  = [TcBinder] -> TcM a -> TcM a
forall a. [TcBinder] -> TcM a -> TcM a
tcExtendBinderStack [ TcId -> TopLevelFlag -> TcBinder
TcIdBndr TcId
mono_id TopLevelFlag
NotTopLevel
                        | MBI { mbi_mono_id :: MonoBindInfo -> TcId
mbi_mono_id = TcId
mono_id } <- [MonoBindInfo]
infos ]
                        TcM a
thing_inside
    -- NotTopLevel: it's a monomorphic binding

---------------------
getMonoBindInfo :: [LocatedA TcMonoBind] -> [MonoBindInfo]
getMonoBindInfo :: [GenLocated SrcSpanAnnA TcMonoBind] -> [MonoBindInfo]
getMonoBindInfo [GenLocated SrcSpanAnnA TcMonoBind]
tc_binds
  = (GenLocated SrcSpanAnnA TcMonoBind
 -> [MonoBindInfo] -> [MonoBindInfo])
-> [MonoBindInfo]
-> [GenLocated SrcSpanAnnA TcMonoBind]
-> [MonoBindInfo]
forall a b. (a -> b -> b) -> b -> [a] -> b
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr (TcMonoBind -> [MonoBindInfo] -> [MonoBindInfo]
get_info (TcMonoBind -> [MonoBindInfo] -> [MonoBindInfo])
-> (GenLocated SrcSpanAnnA TcMonoBind -> TcMonoBind)
-> GenLocated SrcSpanAnnA TcMonoBind
-> [MonoBindInfo]
-> [MonoBindInfo]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. GenLocated SrcSpanAnnA TcMonoBind -> TcMonoBind
forall l e. GenLocated l e -> e
unLoc) [] [GenLocated SrcSpanAnnA TcMonoBind]
tc_binds
  where
    get_info :: TcMonoBind -> [MonoBindInfo] -> [MonoBindInfo]
get_info (TcFunBind MonoBindInfo
info SrcSpan
_ MatchGroup GhcRn (LHsExpr GhcRn)
_)    [MonoBindInfo]
rest = MonoBindInfo
info MonoBindInfo -> [MonoBindInfo] -> [MonoBindInfo]
forall a. a -> [a] -> [a]
: [MonoBindInfo]
rest
    get_info (TcPatBind [MonoBindInfo]
infos LPat GhcTc
_ GRHSs GhcRn (LHsExpr GhcRn)
_ Kind
_) [MonoBindInfo]
rest = [MonoBindInfo]
infos [MonoBindInfo] -> [MonoBindInfo] -> [MonoBindInfo]
forall a. [a] -> [a] -> [a]
++ [MonoBindInfo]
rest


{- Note [Relevant bindings and the binder stack]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
When typecking a binding we extend the TcBinderStack for the RHS of
the binding, with the /monomorphic/ Id.  That way, if we have, say
    f = \x -> blah
and something goes wrong in 'blah', we get a "relevant binding"
looking like  f :: alpha -> beta
This applies if 'f' has a type signature too:
   f :: forall a. [a] -> [a]
   f x = True
We can't unify True with [a], and a relevant binding is f :: [a] -> [a]
If we had the *polymorphic* version of f in the TcBinderStack, it
would not be reported as relevant, because its type is closed.
(See TcErrors.relevantBindings.)

Note [Typechecking pattern bindings]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Look at:
   - typecheck/should_compile/ExPat
   - #12427, typecheck/should_compile/T12427{a,b}

  data T where
    MkT :: Integral a => a -> Int -> T

and suppose t :: T.  Which of these pattern bindings are ok?

  E1. let { MkT p _ = t } in <body>

  E2. let { MkT _ q = t } in <body>

  E3. let { MkT (toInteger -> r) _ = t } in <body>

* (E1) is clearly wrong because the existential 'a' escapes.
  What type could 'p' possibly have?

* (E2) is fine, despite the existential pattern, because
  q::Int, and nothing escapes.

* Even (E3) is fine.  The existential pattern binds a dictionary
  for (Integral a) which the view pattern can use to convert the
  a-valued field to an Integer, so r :: Integer.

An easy way to see all three is to imagine the desugaring.
For (E2) it would look like
    let q = case t of MkT _ q' -> q'
    in <body>


We typecheck pattern bindings as follows.  First tcLhs does this:

  1. Take each type signature q :: ty, partial or complete, and
     instantiate it (with tcLhsSigId) to get a MonoBindInfo.  This
     gives us a fresh "mono_id" qm :: instantiate(ty), where qm has
     a fresh name.

     Any fresh unification variables in instantiate(ty) born here, not
     deep under implications as would happen if we allocated them when
     we encountered q during tcPat.

  2. Build a little environment mapping "q" -> "qm" for those Ids
     with signatures (inst_sig_fun)

  3. Invoke tcLetPat to typecheck the pattern.

     - We pass in the current TcLevel.  This is captured by
       GHC.Tc.Gen.Pat.tcLetPat, and put into the pc_lvl field of PatCtxt, in
       PatEnv.

     - When tcPat finds an existential constructor, it binds fresh
       type variables and dictionaries as usual, increments the TcLevel,
       and emits an implication constraint.

     - When we come to a binder (GHC.Tc.Gen.Pat.tcPatBndr), it looks it up
       in the little environment (the pc_sig_fn field of PatCtxt).

         Success => There was a type signature, so just use it,
                    checking compatibility with the expected type.

         Failure => No type signature.
             Infer case: (happens only outside any constructor pattern)
                         use a unification variable
                         at the outer level pc_lvl

             Check case: use promoteTcType to promote the type
                         to the outer level pc_lvl.  This is the
                         place where we emit a constraint that'll blow
                         up if existential capture takes place

       Result: the type of the binder is always at pc_lvl. This is
       crucial.

  4. Throughout, when we are making up an Id for the pattern-bound variables
     (newLetBndr), we have two cases:

     - If we are generalising (generalisation plan is InferGen or
       CheckGen), then the let_bndr_spec will be LetLclBndr.  In that case
       we want to bind a cloned, local version of the variable, with the
       type given by the pattern context, *not* by the signature (even if
       there is one; see #7268). The mkExport part of the
       generalisation step will do the checking and impedance matching
       against the signature.

     - If for some reason we are not generalising (plan = NoGen), the
       LetBndrSpec will be LetGblBndr.  In that case we must bind the
       global version of the Id, and do so with precisely the type given
       in the signature.  (Then we unify with the type from the pattern
       context type.)


And that's it!  The implication constraints check for the skolem
escape.  It's quite simple and neat, and more expressive than before
e.g. GHC 8.0 rejects (E2) and (E3).

Example for (E1), starting at level 1.  We generate
     p :: beta:1, with constraints (forall:3 a. Integral a => a ~ beta)
The (a~beta) can't float (because of the 'a'), nor be solved (because
beta is untouchable.)

Example for (E2), we generate
     q :: beta:1, with constraint (forall:3 a. Integral a => Int ~ beta)
The beta is untouchable, but floats out of the constraint and can
be solved absolutely fine.


************************************************************************
*                                                                      *
                Generalisation
*                                                                      *
********************************************************************* -}

data GeneralisationPlan
  = NoGen               -- No generalisation, no AbsBinds

  | InferGen            -- Implicit generalisation; there is an AbsBinds
       Bool             --   True <=> apply the MR; generalise only unconstrained type vars

  | CheckGen (LHsBind GhcRn) TcIdSigInfo
                        -- One FunBind with a signature
                        -- Explicit generalisation

-- A consequence of the no-AbsBinds choice (NoGen) is that there is
-- no "polymorphic Id" and "monmomorphic Id"; there is just the one

instance Outputable GeneralisationPlan where
  ppr :: GeneralisationPlan -> SDoc
ppr GeneralisationPlan
NoGen          = String -> SDoc
text String
"NoGen"
  ppr (InferGen Bool
b)   = String -> SDoc
text String
"InferGen" SDoc -> SDoc -> SDoc
<+> Bool -> SDoc
forall a. Outputable a => a -> SDoc
ppr Bool
b
  ppr (CheckGen LHsBind GhcRn
_ TcIdSigInfo
s) = String -> SDoc
text String
"CheckGen" SDoc -> SDoc -> SDoc
<+> TcIdSigInfo -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcIdSigInfo
s

decideGeneralisationPlan
   :: DynFlags -> TopLevelFlag -> IsGroupClosed -> TcSigFun
   -> [LHsBind GhcRn] -> GeneralisationPlan
decideGeneralisationPlan :: DynFlags
-> TopLevelFlag
-> IsGroupClosed
-> TcSigFun
-> [LHsBind GhcRn]
-> GeneralisationPlan
decideGeneralisationPlan DynFlags
dflags TopLevelFlag
top_lvl IsGroupClosed
closed TcSigFun
sig_fn [LHsBind GhcRn]
lbinds
  | Bool
has_partial_sigs                         = Bool -> GeneralisationPlan
InferGen ([Bool] -> Bool
forall (t :: * -> *). Foldable t => t Bool -> Bool
and [Bool]
partial_sig_mrs)
  | Just (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind, TcIdSigInfo
sig) <- Maybe (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn), TcIdSigInfo)
one_funbind_with_sig = LHsBind GhcRn -> TcIdSigInfo -> GeneralisationPlan
CheckGen LHsBind GhcRn
GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
bind TcIdSigInfo
sig
  | Bool
do_not_generalise                        = GeneralisationPlan
NoGen
  | Bool
otherwise                                = Bool -> GeneralisationPlan
InferGen Bool
mono_restriction
  where
    binds :: [HsBindLR GhcRn GhcRn]
binds = (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
 -> HsBindLR GhcRn GhcRn)
-> [GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
-> [HsBindLR GhcRn GhcRn]
forall a b. (a -> b) -> [a] -> [b]
map GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
-> HsBindLR GhcRn GhcRn
forall l e. GenLocated l e -> e
unLoc [LHsBind GhcRn]
[GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)]
lbinds

    partial_sig_mrs :: [Bool]
    -- One for each partial signature (so empty => no partial sigs)
    -- The Bool is True if the signature has no constraint context
    --      so we should apply the MR
    -- See Note [Partial type signatures and generalisation]
    partial_sig_mrs :: [Bool]
partial_sig_mrs
      = [ [GenLocated SrcSpanAnnA (HsType GhcRn)] -> Bool
forall a. [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null ([GenLocated SrcSpanAnnA (HsType GhcRn)] -> Bool)
-> [GenLocated SrcSpanAnnA (HsType GhcRn)] -> Bool
forall a b. (a -> b) -> a -> b
$ Maybe (LHsContext GhcRn) -> HsContext GhcRn
forall (p :: Pass).
Maybe (LHsContext (GhcPass p)) -> HsContext (GhcPass p)
fromMaybeContext Maybe (LHsContext GhcRn)
mtheta
        | TcIdSig (PartialSig { psig_hs_ty :: TcIdSigInfo -> LHsSigWcType GhcRn
psig_hs_ty = LHsSigWcType GhcRn
hs_ty })
            <- TcSigFun -> [Name] -> [TcSigInfo]
forall a b. (a -> Maybe b) -> [a] -> [b]
mapMaybe TcSigFun
sig_fn (CollectFlag GhcRn -> [LHsBind GhcRn] -> [IdP GhcRn]
forall p idR.
CollectPass p =>
CollectFlag p -> [LHsBindLR p idR] -> [IdP p]
collectHsBindListBinders CollectFlag GhcRn
forall p. CollectFlag p
CollNoDictBinders [LHsBind GhcRn]
lbinds)
        , let (Maybe (LHsContext GhcRn)
mtheta, LHsType GhcRn
_) = LHsType GhcRn -> (Maybe (LHsContext GhcRn), LHsType GhcRn)
forall (pass :: Pass).
LHsType (GhcPass pass)
-> (Maybe (LHsContext (GhcPass pass)), LHsType (GhcPass pass))
splitLHsQualTy (LHsSigWcType GhcRn -> LHsType GhcRn
forall p. UnXRec p => LHsSigWcType p -> LHsType p
hsSigWcType LHsSigWcType GhcRn
hs_ty) ]

    has_partial_sigs :: Bool
has_partial_sigs = Bool -> Bool
not ([Bool] -> Bool
forall a. [a] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [Bool]
partial_sig_mrs)

    mono_restriction :: Bool
mono_restriction  = Extension -> DynFlags -> Bool
xopt Extension
LangExt.MonomorphismRestriction DynFlags
dflags
                     Bool -> Bool -> Bool
&& (HsBindLR GhcRn GhcRn -> Bool) -> [HsBindLR GhcRn GhcRn] -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
any HsBindLR GhcRn GhcRn -> Bool
restricted [HsBindLR GhcRn GhcRn]
binds

    do_not_generalise :: Bool
do_not_generalise
      | TopLevelFlag -> Bool
isTopLevel TopLevelFlag
top_lvl             = Bool
False
        -- See Note [Always generalise top-level bindings]

      | IsGroupClosed NameEnv (UniqSet Name)
_ Bool
True <- IsGroupClosed
closed = Bool
False
        -- The 'True' means that all of the group's
        -- free vars have ClosedTypeId=True; so we can ignore
        -- -XMonoLocalBinds, and generalise anyway

      | Bool
otherwise = Extension -> DynFlags -> Bool
xopt Extension
LangExt.MonoLocalBinds DynFlags
dflags

    -- With OutsideIn, all nested bindings are monomorphic
    -- except a single function binding with a signature
    one_funbind_with_sig :: Maybe (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn), TcIdSigInfo)
one_funbind_with_sig
      | [lbind :: LHsBind GhcRn
lbind@(L SrcSpanAnnA
_ (FunBind { fun_id :: forall idL idR. HsBindLR idL idR -> LIdP idL
fun_id = LIdP GhcRn
v }))] <- [LHsBind GhcRn]
lbinds
      , Just (TcIdSig TcIdSigInfo
sig) <- TcSigFun
sig_fn (GenLocated SrcSpanAnnN Name -> Name
forall l e. GenLocated l e -> e
unLoc LIdP GhcRn
GenLocated SrcSpanAnnN Name
v)
      = (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn), TcIdSigInfo)
-> Maybe
     (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn), TcIdSigInfo)
forall a. a -> Maybe a
Just (LHsBind GhcRn
GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
lbind, TcIdSigInfo
sig)
      | Bool
otherwise
      = Maybe (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn), TcIdSigInfo)
forall a. Maybe a
Nothing

    -- The Haskell 98 monomorphism restriction
    restricted :: HsBindLR GhcRn GhcRn -> Bool
restricted (PatBind {})                              = Bool
True
    restricted (VarBind { var_id :: forall idL idR. HsBindLR idL idR -> IdP idL
var_id = IdP GhcRn
v })                  = Name -> Bool
no_sig IdP GhcRn
Name
v
    restricted (FunBind { fun_id :: forall idL idR. HsBindLR idL idR -> LIdP idL
fun_id = LIdP GhcRn
v, fun_matches :: forall idL idR. HsBindLR idL idR -> MatchGroup idR (LHsExpr idR)
fun_matches = MatchGroup GhcRn (LHsExpr GhcRn)
m }) = MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)) -> Bool
forall {id :: Pass} {body}. MatchGroup (GhcPass id) body -> Bool
restricted_match MatchGroup GhcRn (LHsExpr GhcRn)
MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
m
                                                           Bool -> Bool -> Bool
&& Name -> Bool
no_sig (GenLocated SrcSpanAnnN Name -> Name
forall l e. GenLocated l e -> e
unLoc LIdP GhcRn
GenLocated SrcSpanAnnN Name
v)
    restricted HsBindLR GhcRn GhcRn
b = String -> SDoc -> Bool
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"isRestrictedGroup/unrestricted" (HsBindLR GhcRn GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr HsBindLR GhcRn GhcRn
b)

    restricted_match :: MatchGroup (GhcPass id) body -> Bool
restricted_match MatchGroup (GhcPass id) body
mg = MatchGroup (GhcPass id) body -> BKey
forall (id :: Pass) body. MatchGroup (GhcPass id) body -> BKey
matchGroupArity MatchGroup (GhcPass id) body
mg BKey -> BKey -> Bool
forall a. Eq a => a -> a -> Bool
== BKey
0
        -- No args => like a pattern binding
        -- Some args => a function binding

    no_sig :: Name -> Bool
no_sig Name
n = Bool -> Bool
not (TcSigFun -> Name -> Bool
hasCompleteSig TcSigFun
sig_fn Name
n)

isClosedBndrGroup :: TcTypeEnv -> Bag (LHsBind GhcRn) -> IsGroupClosed
isClosedBndrGroup :: TcTypeEnv -> LHsBinds GhcRn -> IsGroupClosed
isClosedBndrGroup TcTypeEnv
type_env LHsBinds GhcRn
binds
  = NameEnv (UniqSet Name) -> Bool -> IsGroupClosed
IsGroupClosed NameEnv (UniqSet Name)
fv_env Bool
type_closed
  where
    type_closed :: Bool
type_closed = (UniqSet Name -> Bool) -> NameEnv (UniqSet Name) -> Bool
forall elt key. (elt -> Bool) -> UniqFM key elt -> Bool
allUFM ((Name -> Bool) -> UniqSet Name -> Bool
nameSetAll Name -> Bool
is_closed_type_id) NameEnv (UniqSet Name)
fv_env

    fv_env :: NameEnv NameSet
    fv_env :: NameEnv (UniqSet Name)
fv_env = [(Name, UniqSet Name)] -> NameEnv (UniqSet Name)
forall a. [(Name, a)] -> NameEnv a
mkNameEnv ([(Name, UniqSet Name)] -> NameEnv (UniqSet Name))
-> [(Name, UniqSet Name)] -> NameEnv (UniqSet Name)
forall a b. (a -> b) -> a -> b
$ (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
 -> [(Name, UniqSet Name)])
-> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
-> [(Name, UniqSet Name)]
forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap (HsBindLR GhcRn GhcRn -> [(Name, UniqSet Name)]
bindFvs (HsBindLR GhcRn GhcRn -> [(Name, UniqSet Name)])
-> (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
    -> HsBindLR GhcRn GhcRn)
-> GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
-> [(Name, UniqSet Name)]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn)
-> HsBindLR GhcRn GhcRn
forall l e. GenLocated l e -> e
unLoc) LHsBinds GhcRn
Bag (GenLocated SrcSpanAnnA (HsBindLR GhcRn GhcRn))
binds

    bindFvs :: HsBindLR GhcRn GhcRn -> [(Name, NameSet)]
    bindFvs :: HsBindLR GhcRn GhcRn -> [(Name, UniqSet Name)]
bindFvs (FunBind { fun_id :: forall idL idR. HsBindLR idL idR -> LIdP idL
fun_id = L SrcSpanAnnN
_ Name
f
                     , fun_ext :: forall idL idR. HsBindLR idL idR -> XFunBind idL idR
fun_ext = XFunBind GhcRn GhcRn
fvs })
       = let open_fvs :: UniqSet Name
open_fvs = UniqSet Name -> UniqSet Name
get_open_fvs XFunBind GhcRn GhcRn
UniqSet Name
fvs
         in [(Name
f, UniqSet Name
open_fvs)]
    bindFvs (PatBind { pat_lhs :: forall idL idR. HsBindLR idL idR -> LPat idL
pat_lhs = LPat GhcRn
pat, pat_ext :: forall idL idR. HsBindLR idL idR -> XPatBind idL idR
pat_ext = XPatBind GhcRn GhcRn
fvs })
       = let open_fvs :: UniqSet Name
open_fvs = UniqSet Name -> UniqSet Name
get_open_fvs XPatBind GhcRn GhcRn
UniqSet Name
fvs
         in [(Name
b, UniqSet Name
open_fvs) | Name
b <- CollectFlag GhcRn -> LPat GhcRn -> [IdP GhcRn]
forall p. CollectPass p => CollectFlag p -> LPat p -> [IdP p]
collectPatBinders CollectFlag GhcRn
forall p. CollectFlag p
CollNoDictBinders LPat GhcRn
pat]
    bindFvs HsBindLR GhcRn GhcRn
_
       = []

    get_open_fvs :: UniqSet Name -> UniqSet Name
get_open_fvs UniqSet Name
fvs = (Name -> Bool) -> UniqSet Name -> UniqSet Name
filterNameSet (Bool -> Bool
not (Bool -> Bool) -> (Name -> Bool) -> Name -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Name -> Bool
is_closed) UniqSet Name
fvs

    is_closed :: Name -> ClosedTypeId
    is_closed :: Name -> Bool
is_closed Name
name
      | Just TcTyThing
thing <- TcTypeEnv -> Name -> Maybe TcTyThing
forall a. NameEnv a -> Name -> Maybe a
lookupNameEnv TcTypeEnv
type_env Name
name
      = case TcTyThing
thing of
          AGlobal {}                     -> Bool
True
          ATcId { tct_info :: TcTyThing -> IdBindingInfo
tct_info = IdBindingInfo
ClosedLet } -> Bool
True
          TcTyThing
_                              -> Bool
False

      | Bool
otherwise
      = Bool
True  -- The free-var set for a top level binding mentions


    is_closed_type_id :: Name -> Bool
    -- We're already removed Global and ClosedLet Ids
    is_closed_type_id :: Name -> Bool
is_closed_type_id Name
name
      | Just TcTyThing
thing <- TcTypeEnv -> Name -> Maybe TcTyThing
forall a. NameEnv a -> Name -> Maybe a
lookupNameEnv TcTypeEnv
type_env Name
name
      = case TcTyThing
thing of
          ATcId { tct_info :: TcTyThing -> IdBindingInfo
tct_info = NonClosedLet UniqSet Name
_ Bool
cl } -> Bool
cl
          ATcId { tct_info :: TcTyThing -> IdBindingInfo
tct_info = IdBindingInfo
NotLetBound }       -> Bool
False
          ATyVar {}                              -> Bool
False
               -- In-scope type variables are not closed!
          TcTyThing
_ -> String -> SDoc -> Bool
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"is_closed_id" (Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
name)

      | Bool
otherwise
      = Bool
True   -- The free-var set for a top level binding mentions
               -- imported things too, so that we can report unused imports
               -- These won't be in the local type env.
               -- Ditto class method etc from the current module

{- Note [Always generalise top-level bindings]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
It is very confusing to apply NoGen to a top level binding. Consider (#20123):
   module M where
     x = 5
     f y = (x, y)

The MR means that x=5 is not generalise, so f's binding is no Closed.  So we'd
be tempted to use NoGen. But that leads to f :: Any -> (Integer, Any), which
is plain stupid.

NoGen is good when we have call sites, but not at top level, where the
function may be exported.  And it's easier to grok "MonoLocalBinds" as
applying to, well, local bindings.
-}

{- *********************************************************************
*                                                                      *
               Error contexts and messages
*                                                                      *
********************************************************************* -}

-- This one is called on LHS, when pat and grhss are both Name
-- and on RHS, when pat is TcId and grhss is still Name
patMonoBindsCtxt :: (OutputableBndrId p)
                 => LPat (GhcPass p) -> GRHSs GhcRn (LHsExpr GhcRn) -> SDoc
patMonoBindsCtxt :: forall (p :: Pass).
OutputableBndrId p =>
LPat (GhcPass p) -> GRHSs GhcRn (LHsExpr GhcRn) -> SDoc
patMonoBindsCtxt LPat (GhcPass p)
pat GRHSs GhcRn (LHsExpr GhcRn)
grhss
  = SDoc -> BKey -> SDoc -> SDoc
hang (String -> SDoc
text String
"In a pattern binding:") BKey
2 (LPat (GhcPass p) -> GRHSs GhcRn (LHsExpr GhcRn) -> SDoc
forall (bndr :: Pass) (p :: Pass).
(OutputableBndrId bndr, OutputableBndrId p) =>
LPat (GhcPass bndr)
-> GRHSs (GhcPass p) (LHsExpr (GhcPass p)) -> SDoc
pprPatBind LPat (GhcPass p)
pat GRHSs GhcRn (LHsExpr GhcRn)
grhss)