{-# LANGUAGE CPP          #-}
{-# LANGUAGE TypeFamilies #-}

{-# OPTIONS_GHC -Wno-incomplete-record-updates #-}

module GHC.Rename.Splice (
        rnTopSpliceDecls,
        rnSpliceType, rnSpliceExpr, rnSplicePat, rnSpliceDecl,
        rnBracket,
        checkThLocalName
        , traceSplice, SpliceInfo(..)
  ) where

#include "HsVersions.h"

import GHC.Prelude

import GHC.Types.Name
import GHC.Types.Name.Set
import GHC.Hs
import GHC.Types.Name.Reader
import GHC.Tc.Utils.Monad
import GHC.Driver.Env.Types

import GHC.Rename.Env
import GHC.Rename.Utils   ( HsDocContext(..), newLocalBndrRn )
import GHC.Rename.Unbound ( isUnboundName )
import GHC.Rename.Module  ( rnSrcDecls, findSplice )
import GHC.Rename.Pat     ( rnPat )
import GHC.Types.Basic    ( TopLevelFlag, isTopLevel )
import GHC.Types.SourceText ( SourceText(..) )
import GHC.Utils.Outputable
import GHC.Unit.Module
import GHC.Types.SrcLoc
import GHC.Rename.HsType ( rnLHsType )

import Control.Monad    ( unless, when )

import {-# SOURCE #-} GHC.Rename.Expr ( rnLExpr )

import GHC.Tc.Utils.Env     ( checkWellStaged, tcMetaTy )

import GHC.Driver.Session
import GHC.Data.FastString
import GHC.Utils.Logger  ( dumpIfSet_dyn_printer, DumpFormat (..), getLogger )
import GHC.Utils.Panic
import GHC.Driver.Hooks
import GHC.Builtin.Names.TH ( decsQTyConName, expQTyConName, liftName
                            , patQTyConName, quoteDecName, quoteExpName
                            , quotePatName, quoteTypeName, typeQTyConName)

import {-# SOURCE #-} GHC.Tc.Gen.Expr   ( tcCheckPolyExpr )
import {-# SOURCE #-} GHC.Tc.Gen.Splice
    ( runMetaD
    , runMetaE
    , runMetaP
    , runMetaT
    , tcTopSpliceExpr
    )

import GHC.Tc.Utils.Zonk

import GHCi.RemoteTypes ( ForeignRef )
import qualified Language.Haskell.TH as TH (Q)

import qualified GHC.LanguageExtensions as LangExt

{-
************************************************************************
*                                                                      *
        Template Haskell brackets
*                                                                      *
************************************************************************
-}

rnBracket :: HsExpr GhcPs -> HsBracket GhcPs -> RnM (HsExpr GhcRn, FreeVars)
rnBracket :: HsExpr GhcPs
-> HsBracket GhcPs -> RnM (HsExpr (GhcPass 'Renamed), Uses)
rnBracket HsExpr GhcPs
e HsBracket GhcPs
br_body
  = forall a. SDoc -> TcM a -> TcM a
addErrCtxt (HsBracket GhcPs -> SDoc
quotationCtxtDoc HsBracket GhcPs
br_body) forall a b. (a -> b) -> a -> b
$
    do { -- Check that -XTemplateHaskellQuotes is enabled and available
         Bool
thQuotesEnabled <- forall gbl lcl. Extension -> TcRnIf gbl lcl Bool
xoptM Extension
LangExt.TemplateHaskellQuotes
       ; forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
unless Bool
thQuotesEnabled forall a b. (a -> b) -> a -> b
$
           forall a. SDoc -> TcRn a
failWith ( [SDoc] -> SDoc
vcat
                      [ String -> SDoc
text String
"Syntax error on" SDoc -> SDoc -> SDoc
<+> forall a. Outputable a => a -> SDoc
ppr HsExpr GhcPs
e
                      , String -> SDoc
text (String
"Perhaps you intended to use TemplateHaskell"
                              forall a. [a] -> [a] -> [a]
++ String
" or TemplateHaskellQuotes") ] )

         -- Check for nested brackets
       ; ThStage
cur_stage <- TcM ThStage
getStage
       ; case ThStage
cur_stage of
           { Splice SpliceType
Typed   -> Bool -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
checkTc (forall id. HsBracket id -> Bool
isTypedBracket HsBracket GhcPs
br_body)
                                       SDoc
illegalUntypedBracket
           ; Splice SpliceType
Untyped -> Bool -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
checkTc (Bool -> Bool
not (forall id. HsBracket id -> Bool
isTypedBracket HsBracket GhcPs
br_body))
                                       SDoc
illegalTypedBracket
           ; RunSplice TcRef [ForeignRef (Q ())]
_    ->
               -- See Note [RunSplice ThLevel] in GHC.Tc.Types.
               forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"rnBracket: Renaming bracket when running a splice"
                        (forall a. Outputable a => a -> SDoc
ppr HsExpr GhcPs
e)
           ; ThStage
Comp           -> forall (m :: * -> *) a. Monad m => a -> m a
return ()
           ; Brack {}       -> forall a. SDoc -> TcRn a
failWithTc SDoc
illegalBracket
           }

         -- Brackets are desugared to code that mentions the TH package
       ; IOEnv (Env TcGblEnv TcLclEnv) ()
recordThUse

       ; case forall id. HsBracket id -> Bool
isTypedBracket HsBracket GhcPs
br_body of
            Bool
True  -> do { String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"Renaming typed TH bracket" SDoc
empty
                        ; (HsBracket (GhcPass 'Renamed)
body', Uses
fvs_e) <-
                          forall a. ThStage -> TcM a -> TcM a
setStage (ThStage -> PendingStuff -> ThStage
Brack ThStage
cur_stage PendingStuff
RnPendingTyped) forall a b. (a -> b) -> a -> b
$
                                   ThStage
-> HsBracket GhcPs -> TcRn (HsBracket (GhcPass 'Renamed), Uses)
rn_bracket ThStage
cur_stage HsBracket GhcPs
br_body
                        ; forall (m :: * -> *) a. Monad m => a -> m a
return (forall p. XBracket p -> HsBracket p -> HsExpr p
HsBracket forall a. EpAnn a
noAnn HsBracket (GhcPass 'Renamed)
body', Uses
fvs_e) }

            Bool
False -> do { String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"Renaming untyped TH bracket" SDoc
empty
                        ; IORef [PendingRnSplice]
ps_var <- forall a env. a -> IOEnv env (IORef a)
newMutVar []
                        ; (HsBracket (GhcPass 'Renamed)
body', Uses
fvs_e) <-
                          -- See Note [Rebindable syntax and Template Haskell]
                          forall gbl lcl a. Extension -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
unsetXOptM Extension
LangExt.RebindableSyntax forall a b. (a -> b) -> a -> b
$
                          forall a. ThStage -> TcM a -> TcM a
setStage (ThStage -> PendingStuff -> ThStage
Brack ThStage
cur_stage (IORef [PendingRnSplice] -> PendingStuff
RnPendingUntyped IORef [PendingRnSplice]
ps_var)) forall a b. (a -> b) -> a -> b
$
                                   ThStage
-> HsBracket GhcPs -> TcRn (HsBracket (GhcPass 'Renamed), Uses)
rn_bracket ThStage
cur_stage HsBracket GhcPs
br_body
                        ; [PendingRnSplice]
pendings <- forall a env. IORef a -> IOEnv env a
readMutVar IORef [PendingRnSplice]
ps_var
                        ; forall (m :: * -> *) a. Monad m => a -> m a
return (forall p.
XRnBracketOut p
-> HsBracket (HsBracketRn p) -> [PendingRnSplice' p] -> HsExpr p
HsRnBracketOut NoExtField
noExtField HsBracket (GhcPass 'Renamed)
body' [PendingRnSplice]
pendings, Uses
fvs_e) }
       }

rn_bracket :: ThStage -> HsBracket GhcPs -> RnM (HsBracket GhcRn, FreeVars)
rn_bracket :: ThStage
-> HsBracket GhcPs -> TcRn (HsBracket (GhcPass 'Renamed), Uses)
rn_bracket ThStage
outer_stage br :: HsBracket GhcPs
br@(VarBr XVarBr GhcPs
x Bool
flg LIdP GhcPs
rdr_name)
  = do { Name
name <- RdrName -> RnM Name
lookupOccRn (forall l e. GenLocated l e -> e
unLoc LIdP GhcPs
rdr_name)
       ; Module
this_mod <- forall (m :: * -> *). HasModule m => m Module
getModule

       ; forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Bool
flg Bool -> Bool -> Bool
&& Module -> Name -> Bool
nameIsLocalOrFrom Module
this_mod Name
name) forall a b. (a -> b) -> a -> b
$
             -- Type variables can be quoted in TH. See #5721.
                 do { Maybe (TopLevelFlag, ThLevel)
mb_bind_lvl <- Name -> RnM (Maybe (TopLevelFlag, ThLevel))
lookupLocalOccThLvl_maybe Name
name
                    ; case Maybe (TopLevelFlag, ThLevel)
mb_bind_lvl of
                        { Maybe (TopLevelFlag, ThLevel)
Nothing -> forall (m :: * -> *) a. Monad m => a -> m a
return ()      -- Can happen for data constructors,
                                                    -- but nothing needs to be done for them

                        ; Just (TopLevelFlag
top_lvl, ThLevel
bind_lvl)  -- See Note [Quoting names]
                             | TopLevelFlag -> Bool
isTopLevel TopLevelFlag
top_lvl
                             -> forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Name -> Bool
isExternalName Name
name) (Name -> IOEnv (Env TcGblEnv TcLclEnv) ()
keepAlive Name
name)
                             | Bool
otherwise
                             -> do { String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"rn_bracket VarBr"
                                      (forall a. Outputable a => a -> SDoc
ppr Name
name SDoc -> SDoc -> SDoc
<+> forall a. Outputable a => a -> SDoc
ppr ThLevel
bind_lvl
                                                SDoc -> SDoc -> SDoc
<+> forall a. Outputable a => a -> SDoc
ppr ThStage
outer_stage)
                                   ; Bool -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
checkTc (ThStage -> ThLevel
thLevel ThStage
outer_stage forall a. Num a => a -> a -> a
+ ThLevel
1 forall a. Eq a => a -> a -> Bool
== ThLevel
bind_lvl)
                                             (HsBracket GhcPs -> SDoc
quotedNameStageErr HsBracket GhcPs
br) }
                        }
                    }
       ; forall (m :: * -> *) a. Monad m => a -> m a
return (forall p. XVarBr p -> Bool -> LIdP p -> HsBracket p
VarBr XVarBr GhcPs
x Bool
flg (forall a an. a -> LocatedAn an a
noLocA Name
name), Name -> Uses
unitFV Name
name) }

rn_bracket ThStage
_ (ExpBr XExpBr GhcPs
x LHsExpr GhcPs
e) = do { (GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
e', Uses
fvs) <- LHsExpr GhcPs -> RnM (LHsExpr (GhcPass 'Renamed), Uses)
rnLExpr LHsExpr GhcPs
e
                            ; forall (m :: * -> *) a. Monad m => a -> m a
return (forall p. XExpBr p -> LHsExpr p -> HsBracket p
ExpBr XExpBr GhcPs
x GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
e', Uses
fvs) }

rn_bracket ThStage
_ (PatBr XPatBr GhcPs
x LPat GhcPs
p)
  = forall a.
HsMatchContext (GhcPass 'Renamed)
-> LPat GhcPs
-> (LPat (GhcPass 'Renamed) -> RnM (a, Uses))
-> RnM (a, Uses)
rnPat forall p. HsMatchContext p
ThPatQuote LPat GhcPs
p forall a b. (a -> b) -> a -> b
$ \ LPat (GhcPass 'Renamed)
p' -> forall (m :: * -> *) a. Monad m => a -> m a
return (forall p. XPatBr p -> LPat p -> HsBracket p
PatBr XPatBr GhcPs
x LPat (GhcPass 'Renamed)
p', Uses
emptyFVs)

rn_bracket ThStage
_ (TypBr XTypBr GhcPs
x LHsType GhcPs
t) = do { (GenLocated SrcSpanAnnA (HsType (GhcPass 'Renamed))
t', Uses
fvs) <- HsDocContext
-> LHsType GhcPs -> RnM (LHsType (GhcPass 'Renamed), Uses)
rnLHsType HsDocContext
TypBrCtx LHsType GhcPs
t
                              ; forall (m :: * -> *) a. Monad m => a -> m a
return (forall p. XTypBr p -> LHsType p -> HsBracket p
TypBr XTypBr GhcPs
x GenLocated SrcSpanAnnA (HsType (GhcPass 'Renamed))
t', Uses
fvs) }

rn_bracket ThStage
_ (DecBrL XDecBrL GhcPs
x [LHsDecl GhcPs]
decls)
  = do { HsGroup GhcPs
group <- [LHsDecl GhcPs] -> RnM (HsGroup GhcPs)
groupDecls [LHsDecl GhcPs]
decls
       ; TcGblEnv
gbl_env  <- forall gbl lcl. TcRnIf gbl lcl gbl
getGblEnv
       ; let new_gbl_env :: TcGblEnv
new_gbl_env = TcGblEnv
gbl_env { tcg_dus :: DefUses
tcg_dus = DefUses
emptyDUs }
                          -- The emptyDUs is so that we just collect uses for this
                          -- group alone in the call to rnSrcDecls below
       ; (TcGblEnv
tcg_env, HsGroup (GhcPass 'Renamed)
group') <- forall gbl lcl a. gbl -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
setGblEnv TcGblEnv
new_gbl_env forall a b. (a -> b) -> a -> b
$
                              HsGroup GhcPs
-> TcRnIf TcGblEnv TcLclEnv (TcGblEnv, HsGroup (GhcPass 'Renamed))
rnSrcDecls HsGroup GhcPs
group

              -- Discard the tcg_env; it contains only extra info about fixity
        ; String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"rn_bracket dec" (forall a. Outputable a => a -> SDoc
ppr (TcGblEnv -> DefUses
tcg_dus TcGblEnv
tcg_env) SDoc -> SDoc -> SDoc
$$
                   forall a. Outputable a => a -> SDoc
ppr (DefUses -> Uses
duUses (TcGblEnv -> DefUses
tcg_dus TcGblEnv
tcg_env)))
        ; forall (m :: * -> *) a. Monad m => a -> m a
return (forall p. XDecBrG p -> HsGroup p -> HsBracket p
DecBrG XDecBrL GhcPs
x HsGroup (GhcPass 'Renamed)
group', DefUses -> Uses
duUses (TcGblEnv -> DefUses
tcg_dus TcGblEnv
tcg_env)) }
  where
    groupDecls :: [LHsDecl GhcPs] -> RnM (HsGroup GhcPs)
    groupDecls :: [LHsDecl GhcPs] -> RnM (HsGroup GhcPs)
groupDecls [LHsDecl GhcPs]
decls
      = do { (HsGroup GhcPs
group, Maybe (SpliceDecl GhcPs, [GenLocated SrcSpanAnnA (HsDecl GhcPs)])
mb_splice) <- [LHsDecl GhcPs]
-> RnM (HsGroup GhcPs, Maybe (SpliceDecl GhcPs, [LHsDecl GhcPs]))
findSplice [LHsDecl GhcPs]
decls
           ; case Maybe (SpliceDecl GhcPs, [GenLocated SrcSpanAnnA (HsDecl GhcPs)])
mb_splice of
           { Maybe (SpliceDecl GhcPs, [GenLocated SrcSpanAnnA (HsDecl GhcPs)])
Nothing -> forall (m :: * -> *) a. Monad m => a -> m a
return HsGroup GhcPs
group
           ; Just (SpliceDecl GhcPs
splice, [GenLocated SrcSpanAnnA (HsDecl GhcPs)]
rest) ->
               do { HsGroup GhcPs
group' <- [LHsDecl GhcPs] -> RnM (HsGroup GhcPs)
groupDecls [GenLocated SrcSpanAnnA (HsDecl GhcPs)]
rest
                  ; let group'' :: HsGroup GhcPs
group'' = forall (p :: Pass).
HsGroup (GhcPass p) -> HsGroup (GhcPass p) -> HsGroup (GhcPass p)
appendGroups HsGroup GhcPs
group HsGroup GhcPs
group'
                  ; forall (m :: * -> *) a. Monad m => a -> m a
return HsGroup GhcPs
group'' { hs_splcds :: [LSpliceDecl GhcPs]
hs_splcds = forall a an. a -> LocatedAn an a
noLocA SpliceDecl GhcPs
splice forall a. a -> [a] -> [a]
: forall p. HsGroup p -> [LSpliceDecl p]
hs_splcds HsGroup GhcPs
group' }
                  }
           }}

rn_bracket ThStage
_ (DecBrG {}) = forall a. String -> a
panic String
"rn_bracket: unexpected DecBrG"

rn_bracket ThStage
_ (TExpBr XTExpBr GhcPs
x LHsExpr GhcPs
e) = do { (GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
e', Uses
fvs) <- LHsExpr GhcPs -> RnM (LHsExpr (GhcPass 'Renamed), Uses)
rnLExpr LHsExpr GhcPs
e
                               ; forall (m :: * -> *) a. Monad m => a -> m a
return (forall p. XTExpBr p -> LHsExpr p -> HsBracket p
TExpBr XTExpBr GhcPs
x GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
e', Uses
fvs) }

quotationCtxtDoc :: HsBracket GhcPs -> SDoc
quotationCtxtDoc :: HsBracket GhcPs -> SDoc
quotationCtxtDoc HsBracket GhcPs
br_body
  = SDoc -> ThLevel -> SDoc -> SDoc
hang (String -> SDoc
text String
"In the Template Haskell quotation")
         ThLevel
2 (forall a. Outputable a => a -> SDoc
ppr HsBracket GhcPs
br_body)

illegalBracket :: SDoc
illegalBracket :: SDoc
illegalBracket =
    String -> SDoc
text String
"Template Haskell brackets cannot be nested" SDoc -> SDoc -> SDoc
<+>
    String -> SDoc
text String
"(without intervening splices)"

illegalTypedBracket :: SDoc
illegalTypedBracket :: SDoc
illegalTypedBracket =
    String -> SDoc
text String
"Typed brackets may only appear in typed splices."

illegalUntypedBracket :: SDoc
illegalUntypedBracket :: SDoc
illegalUntypedBracket =
    String -> SDoc
text String
"Untyped brackets may only appear in untyped splices."

quotedNameStageErr :: HsBracket GhcPs -> SDoc
quotedNameStageErr :: HsBracket GhcPs -> SDoc
quotedNameStageErr HsBracket GhcPs
br
  = [SDoc] -> SDoc
sep [ String -> SDoc
text String
"Stage error: the non-top-level quoted name" SDoc -> SDoc -> SDoc
<+> forall a. Outputable a => a -> SDoc
ppr HsBracket GhcPs
br
        , String -> SDoc
text String
"must be used at the same stage at which it is bound" ]


{-
*********************************************************
*                                                      *
                Splices
*                                                      *
*********************************************************

Note [Free variables of typed splices]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider renaming this:
        f = ...
        h = ...$(thing "f")...

where the splice is a *typed* splice.  The splice can expand into
literally anything, so when we do dependency analysis we must assume
that it might mention 'f'.  So we simply treat all locally-defined
names as mentioned by any splice.  This is terribly brutal, but I
don't see what else to do.  For example, it'll mean that every
locally-defined thing will appear to be used, so no unused-binding
warnings.  But if we miss the dependency, then we might typecheck 'h'
before 'f', and that will crash the type checker because 'f' isn't in
scope.

Currently, I'm not treating a splice as also mentioning every import,
which is a bit inconsistent -- but there are a lot of them.  We might
thereby get some bogus unused-import warnings, but we won't crash the
type checker.  Not very satisfactory really.

Note [Renamer errors]
~~~~~~~~~~~~~~~~~~~~~
It's important to wrap renamer calls in checkNoErrs, because the
renamer does not fail for out of scope variables etc. Instead it
returns a bogus term/type, so that it can report more than one error.
We don't want the type checker to see these bogus unbound variables.
-}

rnSpliceGen :: (HsSplice GhcRn -> RnM (a, FreeVars))
                                            -- Outside brackets, run splice
            -> (HsSplice GhcRn -> (PendingRnSplice, a))
                                            -- Inside brackets, make it pending
            -> HsSplice GhcPs
            -> RnM (a, FreeVars)
rnSpliceGen :: forall a.
(HsSplice (GhcPass 'Renamed) -> RnM (a, Uses))
-> (HsSplice (GhcPass 'Renamed) -> (PendingRnSplice, a))
-> HsSplice GhcPs
-> RnM (a, Uses)
rnSpliceGen HsSplice (GhcPass 'Renamed) -> RnM (a, Uses)
run_splice HsSplice (GhcPass 'Renamed) -> (PendingRnSplice, a)
pend_splice HsSplice GhcPs
splice
  = forall a. SDoc -> TcM a -> TcM a
addErrCtxt (HsSplice GhcPs -> SDoc
spliceCtxt HsSplice GhcPs
splice) forall a b. (a -> b) -> a -> b
$ do
    { ThStage
stage <- TcM ThStage
getStage
    ; case ThStage
stage of
        Brack ThStage
pop_stage PendingStuff
RnPendingTyped
          -> do { Bool -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
checkTc Bool
is_typed_splice SDoc
illegalUntypedSplice
                ; (HsSplice (GhcPass 'Renamed)
splice', Uses
fvs) <- forall a. ThStage -> TcM a -> TcM a
setStage ThStage
pop_stage forall a b. (a -> b) -> a -> b
$
                                    HsSplice GhcPs -> TcRn (HsSplice (GhcPass 'Renamed), Uses)
rnSplice HsSplice GhcPs
splice
                ; let (PendingRnSplice
_pending_splice, a
result) = HsSplice (GhcPass 'Renamed) -> (PendingRnSplice, a)
pend_splice HsSplice (GhcPass 'Renamed)
splice'
                ; forall (m :: * -> *) a. Monad m => a -> m a
return (a
result, Uses
fvs) }

        Brack ThStage
pop_stage (RnPendingUntyped IORef [PendingRnSplice]
ps_var)
          -> do { Bool -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
checkTc (Bool -> Bool
not Bool
is_typed_splice) SDoc
illegalTypedSplice
                ; (HsSplice (GhcPass 'Renamed)
splice', Uses
fvs) <- forall a. ThStage -> TcM a -> TcM a
setStage ThStage
pop_stage forall a b. (a -> b) -> a -> b
$
                                    HsSplice GhcPs -> TcRn (HsSplice (GhcPass 'Renamed), Uses)
rnSplice HsSplice GhcPs
splice
                ; let (PendingRnSplice
pending_splice, a
result) = HsSplice (GhcPass 'Renamed) -> (PendingRnSplice, a)
pend_splice HsSplice (GhcPass 'Renamed)
splice'
                ; [PendingRnSplice]
ps <- forall a env. IORef a -> IOEnv env a
readMutVar IORef [PendingRnSplice]
ps_var
                ; forall a env. IORef a -> a -> IOEnv env ()
writeMutVar IORef [PendingRnSplice]
ps_var (PendingRnSplice
pending_splice forall a. a -> [a] -> [a]
: [PendingRnSplice]
ps)
                ; forall (m :: * -> *) a. Monad m => a -> m a
return (a
result, Uses
fvs) }

        ThStage
_ ->  do { HsSplice GhcPs -> IOEnv (Env TcGblEnv TcLclEnv) ()
checkTopSpliceAllowed HsSplice GhcPs
splice
                 ; (HsSplice (GhcPass 'Renamed)
splice', Uses
fvs1) <- forall r. TcM r -> TcM r
checkNoErrs forall a b. (a -> b) -> a -> b
$
                                         forall a. ThStage -> TcM a -> TcM a
setStage (SpliceType -> ThStage
Splice SpliceType
splice_type) forall a b. (a -> b) -> a -> b
$
                                         HsSplice GhcPs -> TcRn (HsSplice (GhcPass 'Renamed), Uses)
rnSplice HsSplice GhcPs
splice
                   -- checkNoErrs: don't attempt to run the splice if
                   -- renaming it failed; otherwise we get a cascade of
                   -- errors from e.g. unbound variables
                 ; (a
result, Uses
fvs2) <- HsSplice (GhcPass 'Renamed) -> RnM (a, Uses)
run_splice HsSplice (GhcPass 'Renamed)
splice'
                 ; forall (m :: * -> *) a. Monad m => a -> m a
return (a
result, Uses
fvs1 Uses -> Uses -> Uses
`plusFV` Uses
fvs2) } }
   where
     is_typed_splice :: Bool
is_typed_splice = forall id. HsSplice id -> Bool
isTypedSplice HsSplice GhcPs
splice
     splice_type :: SpliceType
splice_type = if Bool
is_typed_splice
                   then SpliceType
Typed
                   else SpliceType
Untyped


-- Nested splices are fine without TemplateHaskell because they
-- are not executed until the top-level splice is run.
checkTopSpliceAllowed :: HsSplice GhcPs -> RnM ()
checkTopSpliceAllowed :: HsSplice GhcPs -> IOEnv (Env TcGblEnv TcLclEnv) ()
checkTopSpliceAllowed HsSplice GhcPs
splice = do
  let (String
herald, Extension
ext) = HsSplice GhcPs -> (String, Extension)
spliceExtension HsSplice GhcPs
splice
  Bool
extEnabled <- forall gbl lcl. Extension -> TcRnIf gbl lcl Bool
xoptM Extension
ext
  forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
unless Bool
extEnabled
    (forall a. SDoc -> TcRn a
failWith forall a b. (a -> b) -> a -> b
$ String -> SDoc
text String
herald SDoc -> SDoc -> SDoc
<+> String -> SDoc
text String
"are not permitted without" SDoc -> SDoc -> SDoc
<+> forall a. Outputable a => a -> SDoc
ppr Extension
ext)
  where
     spliceExtension :: HsSplice GhcPs -> (String, LangExt.Extension)
     spliceExtension :: HsSplice GhcPs -> (String, Extension)
spliceExtension (HsQuasiQuote {}) = (String
"Quasi-quotes", Extension
LangExt.QuasiQuotes)
     spliceExtension (HsTypedSplice {}) = (String
"Top-level splices", Extension
LangExt.TemplateHaskell)
     spliceExtension (HsUntypedSplice {}) = (String
"Top-level splices", Extension
LangExt.TemplateHaskell)
     spliceExtension s :: HsSplice GhcPs
s@(HsSpliced {}) = forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"spliceExtension" (forall a. Outputable a => a -> SDoc
ppr HsSplice GhcPs
s)

------------------

-- | Returns the result of running a splice and the modFinalizers collected
-- during the execution.
--
-- See Note [Delaying modFinalizers in untyped splices].
runRnSplice :: UntypedSpliceFlavour
            -> (LHsExpr GhcTc -> TcRn res)
            -> (res -> SDoc)    -- How to pretty-print res
                                -- Usually just ppr, but not for [Decl]
            -> HsSplice GhcRn   -- Always untyped
            -> TcRn (res, [ForeignRef (TH.Q ())])
runRnSplice :: forall res.
UntypedSpliceFlavour
-> (LHsExpr GhcTc -> TcRn res)
-> (res -> SDoc)
-> HsSplice (GhcPass 'Renamed)
-> TcRn (res, [ForeignRef (Q ())])
runRnSplice UntypedSpliceFlavour
flavour LHsExpr GhcTc -> TcRn res
run_meta res -> SDoc
ppr_res HsSplice (GhcPass 'Renamed)
splice
  = do { Hooks
hooks <- HscEnv -> Hooks
hsc_hooks forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> forall gbl lcl. TcRnIf gbl lcl HscEnv
getTopEnv
       ; HsSplice (GhcPass 'Renamed)
splice' <- case Hooks
-> Maybe
     (HsSplice (GhcPass 'Renamed)
      -> IOEnv (Env TcGblEnv TcLclEnv) (HsSplice (GhcPass 'Renamed)))
runRnSpliceHook Hooks
hooks of
            Maybe
  (HsSplice (GhcPass 'Renamed)
   -> IOEnv (Env TcGblEnv TcLclEnv) (HsSplice (GhcPass 'Renamed)))
Nothing -> forall (m :: * -> *) a. Monad m => a -> m a
return HsSplice (GhcPass 'Renamed)
splice
            Just HsSplice (GhcPass 'Renamed)
-> IOEnv (Env TcGblEnv TcLclEnv) (HsSplice (GhcPass 'Renamed))
h  -> HsSplice (GhcPass 'Renamed)
-> IOEnv (Env TcGblEnv TcLclEnv) (HsSplice (GhcPass 'Renamed))
h HsSplice (GhcPass 'Renamed)
splice

       ; let the_expr :: LHsExpr (GhcPass 'Renamed)
the_expr = case HsSplice (GhcPass 'Renamed)
splice' of
                HsUntypedSplice XUntypedSplice (GhcPass 'Renamed)
_ SpliceDecoration
_ IdP (GhcPass 'Renamed)
_ LHsExpr (GhcPass 'Renamed)
e   ->  LHsExpr (GhcPass 'Renamed)
e
                HsQuasiQuote XQuasiQuote (GhcPass 'Renamed)
_ IdP (GhcPass 'Renamed)
_ IdP (GhcPass 'Renamed)
q SrcSpan
qs FastString
str -> UntypedSpliceFlavour
-> Name -> SrcSpan -> FastString -> LHsExpr (GhcPass 'Renamed)
mkQuasiQuoteExpr UntypedSpliceFlavour
flavour IdP (GhcPass 'Renamed)
q SrcSpan
qs FastString
str
                HsTypedSplice {}          -> forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"runRnSplice" (forall a. Outputable a => a -> SDoc
ppr HsSplice (GhcPass 'Renamed)
splice)
                HsSpliced {}              -> forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"runRnSplice" (forall a. Outputable a => a -> SDoc
ppr HsSplice (GhcPass 'Renamed)
splice)

             -- Typecheck the expression
       ; Type
meta_exp_ty   <- Name -> TcM Type
tcMetaTy Name
meta_ty_name
       ; GenLocated SrcSpanAnnA (HsExpr GhcTc)
zonked_q_expr <- LHsExpr GhcTc -> TcM (LHsExpr GhcTc)
zonkTopLExpr forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
=<<
                            SpliceType -> TcM (LHsExpr GhcTc) -> TcM (LHsExpr GhcTc)
tcTopSpliceExpr SpliceType
Untyped
                              (LHsExpr (GhcPass 'Renamed) -> Type -> TcM (LHsExpr GhcTc)
tcCheckPolyExpr LHsExpr (GhcPass 'Renamed)
the_expr Type
meta_exp_ty)

             -- Run the expression
       ; TcRef [ForeignRef (Q ())]
mod_finalizers_ref <- forall a gbl lcl. a -> TcRnIf gbl lcl (TcRef a)
newTcRef []
       ; res
result <- forall a. ThStage -> TcM a -> TcM a
setStage (TcRef [ForeignRef (Q ())] -> ThStage
RunSplice TcRef [ForeignRef (Q ())]
mod_finalizers_ref) forall a b. (a -> b) -> a -> b
$
                     LHsExpr GhcTc -> TcRn res
run_meta GenLocated SrcSpanAnnA (HsExpr GhcTc)
zonked_q_expr
       ; [ForeignRef (Q ())]
mod_finalizers <- forall a gbl lcl. TcRef a -> TcRnIf gbl lcl a
readTcRef TcRef [ForeignRef (Q ())]
mod_finalizers_ref
       ; SpliceInfo -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceSplice (SpliceInfo { spliceDescription :: String
spliceDescription = String
what
                                 , spliceIsDecl :: Bool
spliceIsDecl      = Bool
is_decl
                                 , spliceSource :: Maybe (LHsExpr (GhcPass 'Renamed))
spliceSource      = forall a. a -> Maybe a
Just LHsExpr (GhcPass 'Renamed)
the_expr
                                 , spliceGenerated :: SDoc
spliceGenerated   = res -> SDoc
ppr_res res
result })

       ; forall (m :: * -> *) a. Monad m => a -> m a
return (res
result, [ForeignRef (Q ())]
mod_finalizers) }

  where
    meta_ty_name :: Name
meta_ty_name = case UntypedSpliceFlavour
flavour of
                       UntypedSpliceFlavour
UntypedExpSplice  -> Name
expQTyConName
                       UntypedSpliceFlavour
UntypedPatSplice  -> Name
patQTyConName
                       UntypedSpliceFlavour
UntypedTypeSplice -> Name
typeQTyConName
                       UntypedSpliceFlavour
UntypedDeclSplice -> Name
decsQTyConName
    what :: String
what = case UntypedSpliceFlavour
flavour of
                  UntypedSpliceFlavour
UntypedExpSplice  -> String
"expression"
                  UntypedSpliceFlavour
UntypedPatSplice  -> String
"pattern"
                  UntypedSpliceFlavour
UntypedTypeSplice -> String
"type"
                  UntypedSpliceFlavour
UntypedDeclSplice -> String
"declarations"
    is_decl :: Bool
is_decl = case UntypedSpliceFlavour
flavour of
                 UntypedSpliceFlavour
UntypedDeclSplice -> Bool
True
                 UntypedSpliceFlavour
_                 -> Bool
False

------------------
makePending :: UntypedSpliceFlavour
            -> HsSplice GhcRn
            -> PendingRnSplice
makePending :: UntypedSpliceFlavour
-> HsSplice (GhcPass 'Renamed) -> PendingRnSplice
makePending UntypedSpliceFlavour
flavour (HsUntypedSplice XUntypedSplice (GhcPass 'Renamed)
_ SpliceDecoration
_ IdP (GhcPass 'Renamed)
n LHsExpr (GhcPass 'Renamed)
e)
  = UntypedSpliceFlavour
-> Name -> LHsExpr (GhcPass 'Renamed) -> PendingRnSplice
PendingRnSplice UntypedSpliceFlavour
flavour IdP (GhcPass 'Renamed)
n LHsExpr (GhcPass 'Renamed)
e
makePending UntypedSpliceFlavour
flavour (HsQuasiQuote XQuasiQuote (GhcPass 'Renamed)
_ IdP (GhcPass 'Renamed)
n IdP (GhcPass 'Renamed)
quoter SrcSpan
q_span FastString
quote)
  = UntypedSpliceFlavour
-> Name -> LHsExpr (GhcPass 'Renamed) -> PendingRnSplice
PendingRnSplice UntypedSpliceFlavour
flavour IdP (GhcPass 'Renamed)
n (UntypedSpliceFlavour
-> Name -> SrcSpan -> FastString -> LHsExpr (GhcPass 'Renamed)
mkQuasiQuoteExpr UntypedSpliceFlavour
flavour IdP (GhcPass 'Renamed)
quoter SrcSpan
q_span FastString
quote)
makePending UntypedSpliceFlavour
_ splice :: HsSplice (GhcPass 'Renamed)
splice@(HsTypedSplice {})
  = forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"makePending" (forall a. Outputable a => a -> SDoc
ppr HsSplice (GhcPass 'Renamed)
splice)
makePending UntypedSpliceFlavour
_ splice :: HsSplice (GhcPass 'Renamed)
splice@(HsSpliced {})
  = forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"makePending" (forall a. Outputable a => a -> SDoc
ppr HsSplice (GhcPass 'Renamed)
splice)

------------------
mkQuasiQuoteExpr :: UntypedSpliceFlavour -> Name -> SrcSpan -> FastString
                 -> LHsExpr GhcRn
-- Return the expression (quoter "...quote...")
-- which is what we must run in a quasi-quote
mkQuasiQuoteExpr :: UntypedSpliceFlavour
-> Name -> SrcSpan -> FastString -> LHsExpr (GhcPass 'Renamed)
mkQuasiQuoteExpr UntypedSpliceFlavour
flavour Name
quoter SrcSpan
q_span' FastString
quote
  = forall l e. l -> e -> GenLocated l e
L SrcSpanAnnA
q_span forall a b. (a -> b) -> a -> b
$ forall p. XApp p -> LHsExpr p -> LHsExpr p -> HsExpr p
HsApp EpAnnCO
noComments (forall l e. l -> e -> GenLocated l e
L SrcSpanAnnA
q_span
             forall a b. (a -> b) -> a -> b
$ forall p. XApp p -> LHsExpr p -> LHsExpr p -> HsExpr p
HsApp EpAnnCO
noComments (forall l e. l -> e -> GenLocated l e
L SrcSpanAnnA
q_span
                    (forall p. XVar p -> LIdP p -> HsExpr p
HsVar NoExtField
noExtField (forall l e. l -> e -> GenLocated l e
L (forall a. SrcSpanAnn' a -> SrcSpanAnnN
la2na SrcSpanAnnA
q_span) Name
quote_selector)))
                                GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
quoterExpr)
                    GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
quoteExpr
  where
    q_span :: SrcSpanAnnA
q_span = forall ann. SrcSpan -> SrcAnn ann
noAnnSrcSpan SrcSpan
q_span'
    quoterExpr :: GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
quoterExpr = forall l e. l -> e -> GenLocated l e
L SrcSpanAnnA
q_span forall a b. (a -> b) -> a -> b
$! forall p. XVar p -> LIdP p -> HsExpr p
HsVar NoExtField
noExtField forall a b. (a -> b) -> a -> b
$! (forall l e. l -> e -> GenLocated l e
L (forall a. SrcSpanAnn' a -> SrcSpanAnnN
la2na SrcSpanAnnA
q_span) Name
quoter)
    quoteExpr :: GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
quoteExpr  = forall l e. l -> e -> GenLocated l e
L SrcSpanAnnA
q_span forall a b. (a -> b) -> a -> b
$! forall p. XLitE p -> HsLit p -> HsExpr p
HsLit EpAnnCO
noComments forall a b. (a -> b) -> a -> b
$! forall x. XHsString x -> FastString -> HsLit x
HsString SourceText
NoSourceText FastString
quote
    quote_selector :: Name
quote_selector = case UntypedSpliceFlavour
flavour of
                       UntypedSpliceFlavour
UntypedExpSplice  -> Name
quoteExpName
                       UntypedSpliceFlavour
UntypedPatSplice  -> Name
quotePatName
                       UntypedSpliceFlavour
UntypedTypeSplice -> Name
quoteTypeName
                       UntypedSpliceFlavour
UntypedDeclSplice -> Name
quoteDecName

---------------------
rnSplice :: HsSplice GhcPs -> RnM (HsSplice GhcRn, FreeVars)
-- Not exported...used for all
rnSplice :: HsSplice GhcPs -> TcRn (HsSplice (GhcPass 'Renamed), Uses)
rnSplice (HsTypedSplice XTypedSplice GhcPs
x SpliceDecoration
hasParen IdP GhcPs
splice_name LHsExpr GhcPs
expr)
  = do  { SrcSpan
loc  <- TcRn SrcSpan
getSrcSpanM
        ; Name
n' <- GenLocated SrcSpanAnnN RdrName -> RnM Name
newLocalBndrRn (forall l e. l -> e -> GenLocated l e
L (forall ann. SrcSpan -> SrcAnn ann
noAnnSrcSpan SrcSpan
loc) IdP GhcPs
splice_name)
        ; (GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
expr', Uses
fvs) <- LHsExpr GhcPs -> RnM (LHsExpr (GhcPass 'Renamed), Uses)
rnLExpr LHsExpr GhcPs
expr
        ; forall (m :: * -> *) a. Monad m => a -> m a
return (forall id.
XTypedSplice id
-> SpliceDecoration -> IdP id -> LHsExpr id -> HsSplice id
HsTypedSplice XTypedSplice GhcPs
x SpliceDecoration
hasParen Name
n' GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
expr', Uses
fvs) }

rnSplice (HsUntypedSplice XUntypedSplice GhcPs
x SpliceDecoration
hasParen IdP GhcPs
splice_name LHsExpr GhcPs
expr)
  = do  { SrcSpan
loc  <- TcRn SrcSpan
getSrcSpanM
        ; Name
n' <- GenLocated SrcSpanAnnN RdrName -> RnM Name
newLocalBndrRn (forall l e. l -> e -> GenLocated l e
L (forall ann. SrcSpan -> SrcAnn ann
noAnnSrcSpan SrcSpan
loc) IdP GhcPs
splice_name)
        ; (GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
expr', Uses
fvs) <- LHsExpr GhcPs -> RnM (LHsExpr (GhcPass 'Renamed), Uses)
rnLExpr LHsExpr GhcPs
expr
        ; forall (m :: * -> *) a. Monad m => a -> m a
return (forall id.
XUntypedSplice id
-> SpliceDecoration -> IdP id -> LHsExpr id -> HsSplice id
HsUntypedSplice XUntypedSplice GhcPs
x SpliceDecoration
hasParen Name
n' GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
expr', Uses
fvs) }

rnSplice (HsQuasiQuote XQuasiQuote GhcPs
x IdP GhcPs
splice_name IdP GhcPs
quoter SrcSpan
q_loc FastString
quote)
  = do  { SrcSpan
loc  <- TcRn SrcSpan
getSrcSpanM
        ; Name
splice_name' <- GenLocated SrcSpanAnnN RdrName -> RnM Name
newLocalBndrRn (forall l e. l -> e -> GenLocated l e
L (forall ann. SrcSpan -> SrcAnn ann
noAnnSrcSpan SrcSpan
loc) IdP GhcPs
splice_name)

          -- Rename the quoter; akin to the HsVar case of rnExpr
        ; Name
quoter' <- RdrName -> RnM Name
lookupOccRn IdP GhcPs
quoter
        ; Module
this_mod <- forall (m :: * -> *). HasModule m => m Module
getModule
        ; forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Module -> Name -> Bool
nameIsLocalOrFrom Module
this_mod Name
quoter') forall a b. (a -> b) -> a -> b
$
          Name -> IOEnv (Env TcGblEnv TcLclEnv) ()
checkThLocalName Name
quoter'

        ; forall (m :: * -> *) a. Monad m => a -> m a
return (forall id.
XQuasiQuote id
-> IdP id -> IdP id -> SrcSpan -> FastString -> HsSplice id
HsQuasiQuote XQuasiQuote GhcPs
x Name
splice_name' Name
quoter' SrcSpan
q_loc FastString
quote
                                                             , Name -> Uses
unitFV Name
quoter') }

rnSplice splice :: HsSplice GhcPs
splice@(HsSpliced {}) = forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"rnSplice" (forall a. Outputable a => a -> SDoc
ppr HsSplice GhcPs
splice)

---------------------
rnSpliceExpr :: HsSplice GhcPs -> RnM (HsExpr GhcRn, FreeVars)
rnSpliceExpr :: HsSplice GhcPs -> RnM (HsExpr (GhcPass 'Renamed), Uses)
rnSpliceExpr HsSplice GhcPs
splice
  = forall a.
(HsSplice (GhcPass 'Renamed) -> RnM (a, Uses))
-> (HsSplice (GhcPass 'Renamed) -> (PendingRnSplice, a))
-> HsSplice GhcPs
-> RnM (a, Uses)
rnSpliceGen HsSplice (GhcPass 'Renamed)
-> RnM (HsExpr (GhcPass 'Renamed), Uses)
run_expr_splice HsSplice (GhcPass 'Renamed)
-> (PendingRnSplice, HsExpr (GhcPass 'Renamed))
pend_expr_splice HsSplice GhcPs
splice
  where
    pend_expr_splice :: HsSplice GhcRn -> (PendingRnSplice, HsExpr GhcRn)
    pend_expr_splice :: HsSplice (GhcPass 'Renamed)
-> (PendingRnSplice, HsExpr (GhcPass 'Renamed))
pend_expr_splice HsSplice (GhcPass 'Renamed)
rn_splice
        = (UntypedSpliceFlavour
-> HsSplice (GhcPass 'Renamed) -> PendingRnSplice
makePending UntypedSpliceFlavour
UntypedExpSplice HsSplice (GhcPass 'Renamed)
rn_splice, forall p. XSpliceE p -> HsSplice p -> HsExpr p
HsSpliceE forall a. EpAnn a
noAnn HsSplice (GhcPass 'Renamed)
rn_splice)

    run_expr_splice :: HsSplice GhcRn -> RnM (HsExpr GhcRn, FreeVars)
    run_expr_splice :: HsSplice (GhcPass 'Renamed)
-> RnM (HsExpr (GhcPass 'Renamed), Uses)
run_expr_splice HsSplice (GhcPass 'Renamed)
rn_splice
      | forall id. HsSplice id -> Bool
isTypedSplice HsSplice (GhcPass 'Renamed)
rn_splice   -- Run it later, in the type checker
      = do {  -- Ugh!  See Note [Splices] above
             String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"rnSpliceExpr: typed expression splice" SDoc
empty
           ; LocalRdrEnv
lcl_rdr <- RnM LocalRdrEnv
getLocalRdrEnv
           ; GlobalRdrEnv
gbl_rdr <- TcRn GlobalRdrEnv
getGlobalRdrEnv
           ; let gbl_names :: Uses
gbl_names = [Name] -> Uses
mkNameSet [GlobalRdrElt -> Name
greMangledName GlobalRdrElt
gre | GlobalRdrElt
gre <- GlobalRdrEnv -> [GlobalRdrElt]
globalRdrEnvElts GlobalRdrEnv
gbl_rdr
                                                     , GlobalRdrElt -> Bool
isLocalGRE GlobalRdrElt
gre]
                 lcl_names :: Uses
lcl_names = [Name] -> Uses
mkNameSet (LocalRdrEnv -> [Name]
localRdrEnvElts LocalRdrEnv
lcl_rdr)

           ; forall (m :: * -> *) a. Monad m => a -> m a
return (forall p. XSpliceE p -> HsSplice p -> HsExpr p
HsSpliceE forall a. EpAnn a
noAnn HsSplice (GhcPass 'Renamed)
rn_splice, Uses
lcl_names Uses -> Uses -> Uses
`plusFV` Uses
gbl_names) }

      | Bool
otherwise  -- Run it here, see Note [Running splices in the Renamer]
      = do { String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"rnSpliceExpr: untyped expression splice" SDoc
empty
           ; (GenLocated SrcSpanAnnA (HsExpr GhcPs)
rn_expr, [ForeignRef (Q ())]
mod_finalizers) <-
                forall res.
UntypedSpliceFlavour
-> (LHsExpr GhcTc -> TcRn res)
-> (res -> SDoc)
-> HsSplice (GhcPass 'Renamed)
-> TcRn (res, [ForeignRef (Q ())])
runRnSplice UntypedSpliceFlavour
UntypedExpSplice LHsExpr GhcTc -> TcM (LHsExpr GhcPs)
runMetaE forall a. Outputable a => a -> SDoc
ppr HsSplice (GhcPass 'Renamed)
rn_splice
           ; (GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
lexpr3, Uses
fvs) <- forall r. TcM r -> TcM r
checkNoErrs (LHsExpr GhcPs -> RnM (LHsExpr (GhcPass 'Renamed), Uses)
rnLExpr GenLocated SrcSpanAnnA (HsExpr GhcPs)
rn_expr)
             -- See Note [Delaying modFinalizers in untyped splices].
           ; forall (m :: * -> *) a. Monad m => a -> m a
return ( forall p. XPar p -> LHsExpr p -> HsExpr p
HsPar forall a. EpAnn a
noAnn forall a b. (a -> b) -> a -> b
$ forall p. XSpliceE p -> HsSplice p -> HsExpr p
HsSpliceE forall a. EpAnn a
noAnn
                            forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall id.
XSpliced id -> ThModFinalizers -> HsSplicedThing id -> HsSplice id
HsSpliced NoExtField
noExtField ([ForeignRef (Q ())] -> ThModFinalizers
ThModFinalizers [ForeignRef (Q ())]
mod_finalizers)
                            forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall id. HsExpr id -> HsSplicedThing id
HsSplicedExpr forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$>
                            GenLocated SrcSpanAnnA (HsExpr (GhcPass 'Renamed))
lexpr3
                    , Uses
fvs)
           }

{- Note [Running splices in the Renamer]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Splices used to be run in the typechecker, which led to (#4364). Since the
renamer must decide which expressions depend on which others, and it cannot
reliably do this for arbitrary splices, we used to conservatively say that
splices depend on all other expressions in scope. Unfortunately, this led to
the problem of cyclic type declarations seen in (#4364). Instead, by
running splices in the renamer, we side-step the problem of determining
dependencies: by the time the dependency analysis happens, any splices have
already been run, and expression dependencies can be determined as usual.

However, see (#9813), for an example where we would like to run splices
*after* performing dependency analysis (that is, after renaming). It would be
desirable to typecheck "non-splicy" expressions (those expressions that do not
contain splices directly or via dependence on an expression that does) before
"splicy" expressions, such that types/expressions within the same declaration
group would be available to `reify` calls, for example consider the following:

> module M where
>   data D = C
>   f = 1
>   g = $(mapM reify ['f, 'D, ''C] ...)

Compilation of this example fails since D/C/f are not in the type environment
and thus cannot be reified as they have not been typechecked by the time the
splice is renamed and thus run.

These requirements are at odds: we do not want to run splices in the renamer as
we wish to first determine dependencies and typecheck certain expressions,
making them available to reify, but cannot accurately determine dependencies
without running splices in the renamer!

Indeed, the conclusion of (#9813) was that it is not worth the complexity
to try and
 a) implement and maintain the code for renaming/typechecking non-splicy
    expressions before splicy expressions,
 b) explain to TH users which expressions are/not available to reify at any
    given point.

-}

{- Note [Rebindable syntax and Template Haskell]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
When processing Template Haskell quotes with Rebindable Syntax (RS) enabled,
there are two possibilities: apply the RS rules to the quotes or don't.

One might expect that with {-# LANGUAGE RebindableSyntax #-} at the top of a
module, any 'if' expression would end up being turned into a call to whatever
'ifThenElse' function is in scope, regardless of whether the said if expression
appears in "normal" Haskell code or in a TH quote. This however comes with its
problems. Consider the following code:

  {-# LANGUAGE TemplateHaskell, RebindableSyntax #-}

  module X where

  import Prelude ( Monad(..), Bool(..), print, ($) )
  import Language.Haskell.TH.Syntax

  $( do stuff <- [| if True then 10 else 15 |]
        runIO $ print stuff
        return [] )

If we apply the RS rules, then GHC would complain about not having suitable
fromInteger/ifThenElse functions in scope. But this quote is just a bit of
Haskell syntax that has yet to be used, or, to put it differently, placed
(spliced) in some context where the said functions might be available. More
generally, untyped TH quotes are meant to work with yet-unbound identifiers.
This tends to show that untyped TH and Rebindable Syntax overall don't play
well together. Users still have the option to splice "normal" if expressions
into modules where RS is enabled, to turn them into applications of
an 'ifThenElse' function of their choice.

Typed TH (TTH) quotes, on the other hand, come with different constraints. They
don't quite have this "delayed" nature: we typecheck them while processing
them, and TTH users expect RS to Just Work in their quotes, exactly like it does
outside of the quotes. There, we do not have to accept unbound identifiers and
we can apply the RS rules both in the typechecking and desugaring of the quotes
without triggering surprising/bad behaviour for users. For instance, the
following code is expected to be rejected (because of the lack of suitable
'fromInteger'/'ifThenElse' functions in scope):

  {-# LANGUAGE TemplateHaskell, RebindableSyntax #-}

  module X where

  import Prelude ( Monad(..), Bool(..), print, ($) )
  import Language.Haskell.TH.Syntax

  $$( do stuff <- [|| if True then 10 else 15 ||]
         runIO $ print stuff
         return [] )

The conclusion is that even if RS is enabled for a given module, GHC disables it
when processing untyped TH quotes from that module, to avoid the aforementioned
problems, but keeps it on while processing typed TH quotes.

This note and approach originated in #18102.

-}

{- Note [Delaying modFinalizers in untyped splices]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

When splices run in the renamer, 'reify' does not have access to the local
type environment (#11832, [1]).

For instance, in

> let x = e in $(reify (mkName "x") >>= runIO . print >> [| return () |])

'reify' cannot find @x@, because the local type environment is not yet
populated. To address this, we allow 'reify' execution to be deferred with
'addModFinalizer'.

> let x = e in $(do addModFinalizer (reify (mkName "x") >>= runIO . print)
                    [| return () |]
                )

The finalizer is run with the local type environment when type checking is
complete.

Since the local type environment is not available in the renamer, we annotate
the tree at the splice point [2] with @HsSpliceE (HsSpliced finalizers e)@ where
@e@ is the result of splicing and @finalizers@ are the finalizers that have been
collected during evaluation of the splice [3]. In our example,

> HsLet
>   (x = e)
>   (HsSpliceE $ HsSpliced [reify (mkName "x") >>= runIO . print]
>                          (HsSplicedExpr $ return ())
>   )

When the typechecker finds the annotation, it inserts the finalizers in the
global environment and exposes the current local environment to them [4, 5, 6].

> addModFinalizersWithLclEnv [reify (mkName "x") >>= runIO . print]

References:

[1] https://gitlab.haskell.org/ghc/ghc/wikis/template-haskell/reify
[2] 'rnSpliceExpr'
[3] 'GHC.Tc.Gen.Splice.qAddModFinalizer'
[4] 'GHC.Tc.Gen.Expr.tcExpr' ('HsSpliceE' ('HsSpliced' ...))
[5] 'GHC.Tc.Gen.HsType.tc_hs_type' ('HsSpliceTy' ('HsSpliced' ...))
[6] 'GHC.Tc.Gen.Pat.tc_pat' ('SplicePat' ('HsSpliced' ...))

-}

----------------------
rnSpliceType :: HsSplice GhcPs -> RnM (HsType GhcRn, FreeVars)
rnSpliceType :: HsSplice GhcPs -> RnM (HsType (GhcPass 'Renamed), Uses)
rnSpliceType HsSplice GhcPs
splice
  = forall a.
(HsSplice (GhcPass 'Renamed) -> RnM (a, Uses))
-> (HsSplice (GhcPass 'Renamed) -> (PendingRnSplice, a))
-> HsSplice GhcPs
-> RnM (a, Uses)
rnSpliceGen HsSplice (GhcPass 'Renamed)
-> RnM (HsType (GhcPass 'Renamed), Uses)
run_type_splice HsSplice (GhcPass 'Renamed)
-> (PendingRnSplice, HsType (GhcPass 'Renamed))
pend_type_splice HsSplice GhcPs
splice
  where
    pend_type_splice :: HsSplice (GhcPass 'Renamed)
-> (PendingRnSplice, HsType (GhcPass 'Renamed))
pend_type_splice HsSplice (GhcPass 'Renamed)
rn_splice
       = ( UntypedSpliceFlavour
-> HsSplice (GhcPass 'Renamed) -> PendingRnSplice
makePending UntypedSpliceFlavour
UntypedTypeSplice HsSplice (GhcPass 'Renamed)
rn_splice
         , forall pass. XSpliceTy pass -> HsSplice pass -> HsType pass
HsSpliceTy NoExtField
noExtField HsSplice (GhcPass 'Renamed)
rn_splice)

    run_type_splice :: HsSplice (GhcPass 'Renamed)
-> RnM (HsType (GhcPass 'Renamed), Uses)
run_type_splice HsSplice (GhcPass 'Renamed)
rn_splice
      = do { String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"rnSpliceType: untyped type splice" SDoc
empty
           ; (GenLocated SrcSpanAnnA (HsType GhcPs)
hs_ty2, [ForeignRef (Q ())]
mod_finalizers) <-
                forall res.
UntypedSpliceFlavour
-> (LHsExpr GhcTc -> TcRn res)
-> (res -> SDoc)
-> HsSplice (GhcPass 'Renamed)
-> TcRn (res, [ForeignRef (Q ())])
runRnSplice UntypedSpliceFlavour
UntypedTypeSplice LHsExpr GhcTc -> TcM (LHsType GhcPs)
runMetaT forall a. Outputable a => a -> SDoc
ppr HsSplice (GhcPass 'Renamed)
rn_splice
           ; (GenLocated SrcSpanAnnA (HsType (GhcPass 'Renamed))
hs_ty3, Uses
fvs) <- do { let doc :: HsDocContext
doc = LHsType GhcPs -> HsDocContext
SpliceTypeCtx GenLocated SrcSpanAnnA (HsType GhcPs)
hs_ty2
                                 ; forall r. TcM r -> TcM r
checkNoErrs forall a b. (a -> b) -> a -> b
$ HsDocContext
-> LHsType GhcPs -> RnM (LHsType (GhcPass 'Renamed), Uses)
rnLHsType HsDocContext
doc GenLocated SrcSpanAnnA (HsType GhcPs)
hs_ty2 }
                                    -- checkNoErrs: see Note [Renamer errors]
             -- See Note [Delaying modFinalizers in untyped splices].
           ; forall (m :: * -> *) a. Monad m => a -> m a
return ( forall pass. XParTy pass -> LHsType pass -> HsType pass
HsParTy forall a. EpAnn a
noAnn
                              forall a b. (a -> b) -> a -> b
$ forall pass. XSpliceTy pass -> HsSplice pass -> HsType pass
HsSpliceTy NoExtField
noExtField
                              forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall id.
XSpliced id -> ThModFinalizers -> HsSplicedThing id -> HsSplice id
HsSpliced NoExtField
noExtField ([ForeignRef (Q ())] -> ThModFinalizers
ThModFinalizers [ForeignRef (Q ())]
mod_finalizers)
                              forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall id. HsType id -> HsSplicedThing id
HsSplicedTy forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$>
                              GenLocated SrcSpanAnnA (HsType (GhcPass 'Renamed))
hs_ty3
                    , Uses
fvs
                    ) }
              -- Wrap the result of the splice in parens so that we don't
              -- lose the outermost location set by runQuasiQuote (#7918)

{- Note [Partial Type Splices]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Partial Type Signatures are partially supported in TH type splices: only
anonymous wild cards are allowed.

  -- ToDo: SLPJ says: I don't understand all this

Normally, named wild cards are collected before renaming a (partial) type
signature. However, TH type splices are run during renaming, i.e. after the
initial traversal, leading to out of scope errors for named wild cards. We
can't just extend the initial traversal to collect the named wild cards in TH
type splices, as we'd need to expand them, which is supposed to happen only
once, during renaming.

Similarly, the extra-constraints wild card is handled right before renaming
too, and is therefore also not supported in a TH type splice. Another reason
to forbid extra-constraints wild cards in TH type splices is that a single
signature can contain many TH type splices, whereas it mustn't contain more
than one extra-constraints wild card. Enforcing would this be hard the way
things are currently organised.

Anonymous wild cards pose no problem, because they start out without names and
are given names during renaming. These names are collected right after
renaming. The names generated for anonymous wild cards in TH type splices will
thus be collected as well.

For more details about renaming wild cards, see GHC.Rename.HsType.rnHsSigWcType

Note that partial type signatures are fully supported in TH declaration
splices, e.g.:

     [d| foo :: _ => _
         foo x y = x == y |]

This is because in this case, the partial type signature can be treated as a
whole signature, instead of as an arbitrary type.

-}


----------------------
-- | Rename a splice pattern. See Note [rnSplicePat]
rnSplicePat :: HsSplice GhcPs -> RnM ( Either (Pat GhcPs) (Pat GhcRn)
                                       , FreeVars)
rnSplicePat :: HsSplice GhcPs
-> RnM (Either (Pat GhcPs) (Pat (GhcPass 'Renamed)), Uses)
rnSplicePat HsSplice GhcPs
splice
  = forall a.
(HsSplice (GhcPass 'Renamed) -> RnM (a, Uses))
-> (HsSplice (GhcPass 'Renamed) -> (PendingRnSplice, a))
-> HsSplice GhcPs
-> RnM (a, Uses)
rnSpliceGen HsSplice (GhcPass 'Renamed)
-> RnM (Either (Pat GhcPs) (Pat (GhcPass 'Renamed)), Uses)
run_pat_splice forall b.
HsSplice (GhcPass 'Renamed)
-> (PendingRnSplice, Either b (Pat (GhcPass 'Renamed)))
pend_pat_splice HsSplice GhcPs
splice
  where
    pend_pat_splice :: HsSplice GhcRn ->
                       (PendingRnSplice, Either b (Pat GhcRn))
    pend_pat_splice :: forall b.
HsSplice (GhcPass 'Renamed)
-> (PendingRnSplice, Either b (Pat (GhcPass 'Renamed)))
pend_pat_splice HsSplice (GhcPass 'Renamed)
rn_splice
      = (UntypedSpliceFlavour
-> HsSplice (GhcPass 'Renamed) -> PendingRnSplice
makePending UntypedSpliceFlavour
UntypedPatSplice HsSplice (GhcPass 'Renamed)
rn_splice
        , forall a b. b -> Either a b
Right (forall p. XSplicePat p -> HsSplice p -> Pat p
SplicePat NoExtField
noExtField HsSplice (GhcPass 'Renamed)
rn_splice))

    run_pat_splice :: HsSplice GhcRn ->
                      RnM (Either (Pat GhcPs) (Pat GhcRn), FreeVars)
    run_pat_splice :: HsSplice (GhcPass 'Renamed)
-> RnM (Either (Pat GhcPs) (Pat (GhcPass 'Renamed)), Uses)
run_pat_splice HsSplice (GhcPass 'Renamed)
rn_splice
      = do { String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"rnSplicePat: untyped pattern splice" SDoc
empty
           ; (GenLocated SrcSpanAnnA (Pat GhcPs)
pat, [ForeignRef (Q ())]
mod_finalizers) <-
                forall res.
UntypedSpliceFlavour
-> (LHsExpr GhcTc -> TcRn res)
-> (res -> SDoc)
-> HsSplice (GhcPass 'Renamed)
-> TcRn (res, [ForeignRef (Q ())])
runRnSplice UntypedSpliceFlavour
UntypedPatSplice LHsExpr GhcTc -> TcM (LPat GhcPs)
runMetaP forall a. Outputable a => a -> SDoc
ppr HsSplice (GhcPass 'Renamed)
rn_splice
             -- See Note [Delaying modFinalizers in untyped splices].
           ; forall (m :: * -> *) a. Monad m => a -> m a
return ( forall a b. a -> Either a b
Left forall a b. (a -> b) -> a -> b
$ forall p. XParPat p -> LPat p -> Pat p
ParPat forall a. EpAnn a
noAnn forall a b. (a -> b) -> a -> b
$ ((forall p. XSplicePat p -> HsSplice p -> Pat p
SplicePat NoExtField
noExtField)
                              forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall id.
XSpliced id -> ThModFinalizers -> HsSplicedThing id -> HsSplice id
HsSpliced NoExtField
noExtField ([ForeignRef (Q ())] -> ThModFinalizers
ThModFinalizers [ForeignRef (Q ())]
mod_finalizers)
                              forall b c a. (b -> c) -> (a -> b) -> a -> c
. forall id. Pat id -> HsSplicedThing id
HsSplicedPat)  forall a b l. (a -> b) -> GenLocated l a -> GenLocated l b
`mapLoc`
                              GenLocated SrcSpanAnnA (Pat GhcPs)
pat
                    , Uses
emptyFVs
                    ) }
              -- Wrap the result of the quasi-quoter in parens so that we don't
              -- lose the outermost location set by runQuasiQuote (#7918)

----------------------
rnSpliceDecl :: SpliceDecl GhcPs -> RnM (SpliceDecl GhcRn, FreeVars)
rnSpliceDecl :: SpliceDecl GhcPs -> RnM (SpliceDecl (GhcPass 'Renamed), Uses)
rnSpliceDecl (SpliceDecl XSpliceDecl GhcPs
_ (L SrcSpanAnnA
loc HsSplice GhcPs
splice) SpliceExplicitFlag
flg)
  = forall a.
(HsSplice (GhcPass 'Renamed) -> RnM (a, Uses))
-> (HsSplice (GhcPass 'Renamed) -> (PendingRnSplice, a))
-> HsSplice GhcPs
-> RnM (a, Uses)
rnSpliceGen forall {a} {a}. Outputable a => a -> a
run_decl_splice HsSplice (GhcPass 'Renamed)
-> (PendingRnSplice, SpliceDecl (GhcPass 'Renamed))
pend_decl_splice HsSplice GhcPs
splice
  where
    pend_decl_splice :: HsSplice (GhcPass 'Renamed)
-> (PendingRnSplice, SpliceDecl (GhcPass 'Renamed))
pend_decl_splice HsSplice (GhcPass 'Renamed)
rn_splice
       = ( UntypedSpliceFlavour
-> HsSplice (GhcPass 'Renamed) -> PendingRnSplice
makePending UntypedSpliceFlavour
UntypedDeclSplice HsSplice (GhcPass 'Renamed)
rn_splice
         , forall p.
XSpliceDecl p
-> XRec p (HsSplice p) -> SpliceExplicitFlag -> SpliceDecl p
SpliceDecl NoExtField
noExtField (forall l e. l -> e -> GenLocated l e
L SrcSpanAnnA
loc HsSplice (GhcPass 'Renamed)
rn_splice) SpliceExplicitFlag
flg)

    run_decl_splice :: a -> a
run_decl_splice a
rn_splice  = forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"rnSpliceDecl" (forall a. Outputable a => a -> SDoc
ppr a
rn_splice)

rnTopSpliceDecls :: HsSplice GhcPs -> RnM ([LHsDecl GhcPs], FreeVars)
-- Declaration splice at the very top level of the module
rnTopSpliceDecls :: HsSplice GhcPs -> RnM ([LHsDecl GhcPs], Uses)
rnTopSpliceDecls HsSplice GhcPs
splice
   =  do { HsSplice GhcPs -> IOEnv (Env TcGblEnv TcLclEnv) ()
checkTopSpliceAllowed HsSplice GhcPs
splice
         ; (HsSplice (GhcPass 'Renamed)
rn_splice, Uses
fvs) <- forall r. TcM r -> TcM r
checkNoErrs forall a b. (a -> b) -> a -> b
$
                               forall a. ThStage -> TcM a -> TcM a
setStage (SpliceType -> ThStage
Splice SpliceType
Untyped) forall a b. (a -> b) -> a -> b
$
                               HsSplice GhcPs -> TcRn (HsSplice (GhcPass 'Renamed), Uses)
rnSplice HsSplice GhcPs
splice
           -- As always, be sure to checkNoErrs above lest we end up with
           -- holes making it to typechecking, hence #12584.
           --
           -- Note that we cannot call checkNoErrs for the whole duration
           -- of rnTopSpliceDecls. The reason is that checkNoErrs changes
           -- the local environment to temporarily contain a new
           -- reference to store errors, and add_mod_finalizers would
           -- cause this reference to be stored after checkNoErrs finishes.
           -- This is checked by test TH_finalizer.
         ; String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"rnTopSpliceDecls: untyped declaration splice" SDoc
empty
         ; ([GenLocated SrcSpanAnnA (HsDecl GhcPs)]
decls, [ForeignRef (Q ())]
mod_finalizers) <- forall r. TcM r -> TcM r
checkNoErrs forall a b. (a -> b) -> a -> b
$
               forall res.
UntypedSpliceFlavour
-> (LHsExpr GhcTc -> TcRn res)
-> (res -> SDoc)
-> HsSplice (GhcPass 'Renamed)
-> TcRn (res, [ForeignRef (Q ())])
runRnSplice UntypedSpliceFlavour
UntypedDeclSplice LHsExpr GhcTc -> TcM [LHsDecl GhcPs]
runMetaD [LHsDecl GhcPs] -> SDoc
ppr_decls HsSplice (GhcPass 'Renamed)
rn_splice
         ; [ForeignRef (Q ())] -> IOEnv (Env TcGblEnv TcLclEnv) ()
add_mod_finalizers_now [ForeignRef (Q ())]
mod_finalizers
         ; forall (m :: * -> *) a. Monad m => a -> m a
return ([GenLocated SrcSpanAnnA (HsDecl GhcPs)]
decls,Uses
fvs) }
   where
     ppr_decls :: [LHsDecl GhcPs] -> SDoc
     ppr_decls :: [LHsDecl GhcPs] -> SDoc
ppr_decls [LHsDecl GhcPs]
ds = [SDoc] -> SDoc
vcat (forall a b. (a -> b) -> [a] -> [b]
map forall a. Outputable a => a -> SDoc
ppr [LHsDecl GhcPs]
ds)

     -- Adds finalizers to the global environment instead of delaying them
     -- to the type checker.
     --
     -- Declaration splices do not have an interesting local environment so
     -- there is no point in delaying them.
     --
     -- See Note [Delaying modFinalizers in untyped splices].
     add_mod_finalizers_now :: [ForeignRef (TH.Q ())] -> TcRn ()
     add_mod_finalizers_now :: [ForeignRef (Q ())] -> IOEnv (Env TcGblEnv TcLclEnv) ()
add_mod_finalizers_now []             = forall (m :: * -> *) a. Monad m => a -> m a
return ()
     add_mod_finalizers_now [ForeignRef (Q ())]
mod_finalizers = do
       TcRef [(TcLclEnv, ThModFinalizers)]
th_modfinalizers_var <- forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap TcGblEnv -> TcRef [(TcLclEnv, ThModFinalizers)]
tcg_th_modfinalizers forall gbl lcl. TcRnIf gbl lcl gbl
getGblEnv
       TcLclEnv
env <- forall gbl lcl. TcRnIf gbl lcl lcl
getLclEnv
       forall a gbl lcl. TcRef a -> (a -> a) -> TcRnIf gbl lcl ()
updTcRef TcRef [(TcLclEnv, ThModFinalizers)]
th_modfinalizers_var forall a b. (a -> b) -> a -> b
$ \[(TcLclEnv, ThModFinalizers)]
fins ->
         (TcLclEnv
env, [ForeignRef (Q ())] -> ThModFinalizers
ThModFinalizers [ForeignRef (Q ())]
mod_finalizers) forall a. a -> [a] -> [a]
: [(TcLclEnv, ThModFinalizers)]
fins


{-
Note [rnSplicePat]
~~~~~~~~~~~~~~~~~~
Renaming a pattern splice is a bit tricky, because we need the variables
bound in the pattern to be in scope in the RHS of the pattern. This scope
management is effectively done by using continuation-passing style in
GHC.Rename.Pat, through the CpsRn monad. We don't wish to be in that monad here
(it would create import cycles and generally conflict with renaming other
splices), so we really want to return a (Pat RdrName) -- the result of
running the splice -- which can then be further renamed in GHC.Rename.Pat, in
the CpsRn monad.

The problem is that if we're renaming a splice within a bracket, we
*don't* want to run the splice now. We really do just want to rename
it to an HsSplice Name. Of course, then we can't know what variables
are bound within the splice. So we accept any unbound variables and
rename them again when the bracket is spliced in.  If a variable is brought
into scope by a pattern splice all is fine.  If it is not then an error is
reported.

In any case, when we're done in rnSplicePat, we'll either have a
Pat RdrName (the result of running a top-level splice) or a Pat Name
(the renamed nested splice). Thus, the awkward return type of
rnSplicePat.
-}

spliceCtxt :: HsSplice GhcPs -> SDoc
spliceCtxt :: HsSplice GhcPs -> SDoc
spliceCtxt HsSplice GhcPs
splice
  = SDoc -> ThLevel -> SDoc -> SDoc
hang (String -> SDoc
text String
"In the" SDoc -> SDoc -> SDoc
<+> SDoc
what) ThLevel
2 (forall a. Outputable a => a -> SDoc
ppr HsSplice GhcPs
splice)
  where
    what :: SDoc
what = case HsSplice GhcPs
splice of
             HsUntypedSplice {} -> String -> SDoc
text String
"untyped splice:"
             HsTypedSplice   {} -> String -> SDoc
text String
"typed splice:"
             HsQuasiQuote    {} -> String -> SDoc
text String
"quasi-quotation:"
             HsSpliced       {} -> String -> SDoc
text String
"spliced expression:"

-- | The splice data to be logged
data SpliceInfo
  = SpliceInfo
    { SpliceInfo -> String
spliceDescription  :: String
    , SpliceInfo -> Maybe (LHsExpr (GhcPass 'Renamed))
spliceSource       :: Maybe (LHsExpr GhcRn) -- Nothing <=> top-level decls
                                                  --        added by addTopDecls
    , SpliceInfo -> Bool
spliceIsDecl       :: Bool    -- True <=> put the generate code in a file
                                    --          when -dth-dec-file is on
    , SpliceInfo -> SDoc
spliceGenerated    :: SDoc
    }
        -- Note that 'spliceSource' is *renamed* but not *typechecked*
        -- Reason (a) less typechecking crap
        --        (b) data constructors after type checking have been
        --            changed to their *wrappers*, and that makes them
        --            print always fully qualified

-- | outputs splice information for 2 flags which have different output formats:
-- `-ddump-splices` and `-dth-dec-file`
traceSplice :: SpliceInfo -> TcM ()
traceSplice :: SpliceInfo -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceSplice (SpliceInfo { spliceDescription :: SpliceInfo -> String
spliceDescription = String
sd, spliceSource :: SpliceInfo -> Maybe (LHsExpr (GhcPass 'Renamed))
spliceSource = Maybe (LHsExpr (GhcPass 'Renamed))
mb_src
                        , spliceGenerated :: SpliceInfo -> SDoc
spliceGenerated = SDoc
gen, spliceIsDecl :: SpliceInfo -> Bool
spliceIsDecl = Bool
is_decl })
  = do SrcSpan
loc <- case Maybe (LHsExpr (GhcPass 'Renamed))
mb_src of
                 Maybe (LHsExpr (GhcPass 'Renamed))
Nothing        -> TcRn SrcSpan
getSrcSpanM
                 Just (L SrcSpanAnnA
loc HsExpr (GhcPass 'Renamed)
_) -> forall (m :: * -> *) a. Monad m => a -> m a
return (forall a. SrcSpanAnn' a -> SrcSpan
locA SrcSpanAnnA
loc)
       DumpFlag -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceOptTcRn DumpFlag
Opt_D_dump_splices (SrcSpan -> SDoc
spliceDebugDoc SrcSpan
loc)

       forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when Bool
is_decl forall a b. (a -> b) -> a -> b
$ do -- Raw material for -dth-dec-file
        DynFlags
dflags <- forall (m :: * -> *). HasDynFlags m => m DynFlags
getDynFlags
        Logger
logger <- forall (m :: * -> *). HasLogger m => m Logger
getLogger
        forall (m :: * -> *) a. MonadIO m => IO a -> m a
liftIO forall a b. (a -> b) -> a -> b
$ PrintUnqualified
-> Logger
-> DynFlags
-> DumpFlag
-> String
-> DumpFormat
-> SDoc
-> IO ()
dumpIfSet_dyn_printer PrintUnqualified
alwaysQualify Logger
logger DynFlags
dflags DumpFlag
Opt_D_th_dec_file
                                       String
"" DumpFormat
FormatHaskell (SrcSpan -> SDoc
spliceCodeDoc SrcSpan
loc)
  where
    -- `-ddump-splices`
    spliceDebugDoc :: SrcSpan -> SDoc
    spliceDebugDoc :: SrcSpan -> SDoc
spliceDebugDoc SrcSpan
loc
      = let code :: [SDoc]
code = case Maybe (LHsExpr (GhcPass 'Renamed))
mb_src of
                     Maybe (LHsExpr (GhcPass 'Renamed))
Nothing -> [SDoc]
ending
                     Just LHsExpr (GhcPass 'Renamed)
e  -> ThLevel -> SDoc -> SDoc
nest ThLevel
2 (forall a. Outputable a => a -> SDoc
ppr (forall (p :: Pass). LHsExpr (GhcPass p) -> LHsExpr (GhcPass p)
stripParensLHsExpr LHsExpr (GhcPass 'Renamed)
e)) forall a. a -> [a] -> [a]
: [SDoc]
ending
            ending :: [SDoc]
ending = [ String -> SDoc
text String
"======>", ThLevel -> SDoc -> SDoc
nest ThLevel
2 SDoc
gen ]
        in  SDoc -> ThLevel -> SDoc -> SDoc
hang (forall a. Outputable a => a -> SDoc
ppr SrcSpan
loc SDoc -> SDoc -> SDoc
<> SDoc
colon SDoc -> SDoc -> SDoc
<+> String -> SDoc
text String
"Splicing" SDoc -> SDoc -> SDoc
<+> String -> SDoc
text String
sd)
               ThLevel
2 ([SDoc] -> SDoc
sep [SDoc]
code)

    -- `-dth-dec-file`
    spliceCodeDoc :: SrcSpan -> SDoc
    spliceCodeDoc :: SrcSpan -> SDoc
spliceCodeDoc SrcSpan
loc
      = [SDoc] -> SDoc
vcat [ String -> SDoc
text String
"--" SDoc -> SDoc -> SDoc
<+> forall a. Outputable a => a -> SDoc
ppr SrcSpan
loc SDoc -> SDoc -> SDoc
<> SDoc
colon SDoc -> SDoc -> SDoc
<+> String -> SDoc
text String
"Splicing" SDoc -> SDoc -> SDoc
<+> String -> SDoc
text String
sd
             , SDoc
gen ]

illegalTypedSplice :: SDoc
illegalTypedSplice :: SDoc
illegalTypedSplice = String -> SDoc
text String
"Typed splices may not appear in untyped brackets"

illegalUntypedSplice :: SDoc
illegalUntypedSplice :: SDoc
illegalUntypedSplice = String -> SDoc
text String
"Untyped splices may not appear in typed brackets"

checkThLocalName :: Name -> RnM ()
checkThLocalName :: Name -> IOEnv (Env TcGblEnv TcLclEnv) ()
checkThLocalName Name
name
  | Name -> Bool
isUnboundName Name
name   -- Do not report two errors for
  = forall (m :: * -> *) a. Monad m => a -> m a
return ()            --   $(not_in_scope args)

  | Bool
otherwise
  = do  { String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"checkThLocalName" (forall a. Outputable a => a -> SDoc
ppr Name
name)
        ; Maybe (TopLevelFlag, ThLevel, ThStage)
mb_local_use <- Name -> TcRn (Maybe (TopLevelFlag, ThLevel, ThStage))
getStageAndBindLevel Name
name
        ; case Maybe (TopLevelFlag, ThLevel, ThStage)
mb_local_use of {
             Maybe (TopLevelFlag, ThLevel, ThStage)
Nothing -> forall (m :: * -> *) a. Monad m => a -> m a
return () ;  -- Not a locally-bound thing
             Just (TopLevelFlag
top_lvl, ThLevel
bind_lvl, ThStage
use_stage) ->
    do  { let use_lvl :: ThLevel
use_lvl = ThStage -> ThLevel
thLevel ThStage
use_stage
        ; SDoc -> ThLevel -> ThLevel -> IOEnv (Env TcGblEnv TcLclEnv) ()
checkWellStaged (SDoc -> SDoc
quotes (forall a. Outputable a => a -> SDoc
ppr Name
name)) ThLevel
bind_lvl ThLevel
use_lvl
        ; String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"checkThLocalName" (forall a. Outputable a => a -> SDoc
ppr Name
name SDoc -> SDoc -> SDoc
<+> forall a. Outputable a => a -> SDoc
ppr ThLevel
bind_lvl
                                               SDoc -> SDoc -> SDoc
<+> forall a. Outputable a => a -> SDoc
ppr ThStage
use_stage
                                               SDoc -> SDoc -> SDoc
<+> forall a. Outputable a => a -> SDoc
ppr ThLevel
use_lvl)
        ; TopLevelFlag
-> ThLevel
-> ThStage
-> ThLevel
-> Name
-> IOEnv (Env TcGblEnv TcLclEnv) ()
checkCrossStageLifting TopLevelFlag
top_lvl ThLevel
bind_lvl ThStage
use_stage ThLevel
use_lvl Name
name } } }

--------------------------------------
checkCrossStageLifting :: TopLevelFlag -> ThLevel -> ThStage -> ThLevel
                       -> Name -> TcM ()
-- We are inside brackets, and (use_lvl > bind_lvl)
-- Now we must check whether there's a cross-stage lift to do
-- Examples   \x -> [| x |]
--            [| map |]
--
-- This code is similar to checkCrossStageLifting in GHC.Tc.Gen.Expr, but
-- this is only run on *untyped* brackets.

checkCrossStageLifting :: TopLevelFlag
-> ThLevel
-> ThStage
-> ThLevel
-> Name
-> IOEnv (Env TcGblEnv TcLclEnv) ()
checkCrossStageLifting TopLevelFlag
top_lvl ThLevel
bind_lvl ThStage
use_stage ThLevel
use_lvl Name
name
  | Brack ThStage
_ (RnPendingUntyped IORef [PendingRnSplice]
ps_var) <- ThStage
use_stage   -- Only for untyped brackets
  , ThLevel
use_lvl forall a. Ord a => a -> a -> Bool
> ThLevel
bind_lvl                               -- Cross-stage condition
  = TopLevelFlag
-> Name
-> IORef [PendingRnSplice]
-> IOEnv (Env TcGblEnv TcLclEnv) ()
check_cross_stage_lifting TopLevelFlag
top_lvl Name
name IORef [PendingRnSplice]
ps_var
  | Bool
otherwise
  = forall (m :: * -> *) a. Monad m => a -> m a
return ()

check_cross_stage_lifting :: TopLevelFlag -> Name -> TcRef [PendingRnSplice] -> TcM ()
check_cross_stage_lifting :: TopLevelFlag
-> Name
-> IORef [PendingRnSplice]
-> IOEnv (Env TcGblEnv TcLclEnv) ()
check_cross_stage_lifting TopLevelFlag
top_lvl Name
name IORef [PendingRnSplice]
ps_var
  | TopLevelFlag -> Bool
isTopLevel TopLevelFlag
top_lvl
        -- Top-level identifiers in this module,
        -- (which have External Names)
        -- are just like the imported case:
        -- no need for the 'lifting' treatment
        -- E.g.  this is fine:
        --   f x = x
        --   g y = [| f 3 |]
  = forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Name -> Bool
isExternalName Name
name) (Name -> IOEnv (Env TcGblEnv TcLclEnv) ()
keepAlive Name
name)
    -- See Note [Keeping things alive for Template Haskell]

  | Bool
otherwise
  =     -- Nested identifiers, such as 'x' in
        -- E.g. \x -> [| h x |]
        -- We must behave as if the reference to x was
        --      h $(lift x)
        -- We use 'x' itself as the SplicePointName, used by
        -- the desugarer to stitch it all back together.
        -- If 'x' occurs many times we may get many identical
        -- bindings of the same SplicePointName, but that doesn't
        -- matter, although it's a mite untidy.
    do  { String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
traceRn String
"checkCrossStageLifting" (forall a. Outputable a => a -> SDoc
ppr Name
name)

          -- Construct the (lift x) expression
        ; let lift_expr :: LHsExpr (GhcPass 'Renamed)
lift_expr   = forall (id :: Pass).
IsPass id =>
LHsExpr (GhcPass id)
-> LHsExpr (GhcPass id) -> LHsExpr (GhcPass id)
nlHsApp (forall (p :: Pass) a.
IsSrcSpanAnn p a =>
IdP (GhcPass p) -> LHsExpr (GhcPass p)
nlHsVar Name
liftName) (forall (p :: Pass) a.
IsSrcSpanAnn p a =>
IdP (GhcPass p) -> LHsExpr (GhcPass p)
nlHsVar Name
name)
              pend_splice :: PendingRnSplice
pend_splice = UntypedSpliceFlavour
-> Name -> LHsExpr (GhcPass 'Renamed) -> PendingRnSplice
PendingRnSplice UntypedSpliceFlavour
UntypedExpSplice Name
name LHsExpr (GhcPass 'Renamed)
lift_expr

          -- Warning for implicit lift (#17804)
        ; forall gbl lcl.
WarningFlag -> TcRnIf gbl lcl () -> TcRnIf gbl lcl ()
whenWOptM WarningFlag
Opt_WarnImplicitLift forall a b. (a -> b) -> a -> b
$
            WarnReason -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) ()
addWarnTc (WarningFlag -> WarnReason
Reason WarningFlag
Opt_WarnImplicitLift)
                       (String -> SDoc
text String
"The variable" SDoc -> SDoc -> SDoc
<+> SDoc -> SDoc
quotes (forall a. Outputable a => a -> SDoc
ppr Name
name) SDoc -> SDoc -> SDoc
<+>
                        String -> SDoc
text String
"is implicitly lifted in the TH quotation")

          -- Update the pending splices
        ; [PendingRnSplice]
ps <- forall a env. IORef a -> IOEnv env a
readMutVar IORef [PendingRnSplice]
ps_var
        ; forall a env. IORef a -> a -> IOEnv env ()
writeMutVar IORef [PendingRnSplice]
ps_var (PendingRnSplice
pend_splice forall a. a -> [a] -> [a]
: [PendingRnSplice]
ps) }

{-
Note [Keeping things alive for Template Haskell]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider
  f x = x+1
  g y = [| f 3 |]

Here 'f' is referred to from inside the bracket, which turns into data
and mentions only f's *name*, not 'f' itself. So we need some other
way to keep 'f' alive, lest it get dropped as dead code.  That's what
keepAlive does. It puts it in the keep-alive set, which subsequently
ensures that 'f' stays as a top level binding.

This must be done by the renamer, not the type checker (as of old),
because the type checker doesn't typecheck the body of untyped
brackets (#8540).

A thing can have a bind_lvl of outerLevel, but have an internal name:
   foo = [d| op = 3
             bop = op + 1 |]
Here the bind_lvl of 'op' is (bogusly) outerLevel, even though it is
bound inside a bracket.  That is because we don't even record
binding levels for top-level things; the binding levels are in the
LocalRdrEnv.

So the occurrence of 'op' in the rhs of 'bop' looks a bit like a
cross-stage thing, but it isn't really.  And in fact we never need
to do anything here for top-level bound things, so all is fine, if
a bit hacky.

For these chaps (which have Internal Names) we don't want to put
them in the keep-alive set.

Note [Quoting names]
~~~~~~~~~~~~~~~~~~~~
A quoted name 'n is a bit like a quoted expression [| n |], except that we
have no cross-stage lifting (c.f. GHC.Tc.Gen.Expr.thBrackId).  So, after incrementing
the use-level to account for the brackets, the cases are:

        bind > use                      Error
        bind = use+1                    OK
        bind < use
                Imported things         OK
                Top-level things        OK
                Non-top-level           Error

where 'use' is the binding level of the 'n quote. (So inside the implied
bracket the level would be use+1.)

Examples:

  f 'map        -- OK; also for top-level defns of this module

  \x. f 'x      -- Not ok (bind = 1, use = 1)
                -- (whereas \x. f [| x |] might have been ok, by
                --                               cross-stage lifting

  \y. [| \x. $(f 'y) |] -- Not ok (bind =1, use = 1)

  [| \x. $(f 'x) |]     -- OK (bind = 2, use = 1)
-}