module RnSource (
        rnSrcDecls, addTcgDUs, rnTyClDecls, findSplice
    ) where

#include "HsVersions.h"

import {-# SOURCE #-} RnExpr( rnLExpr )
import {-# SOURCE #-} RnSplice ( rnSpliceDecl )
import {-# SOURCE #-} TcSplice ( runQuasiQuoteDecl )

import HsSyn
import RdrName
import RnTypes
import RnBinds
import RnEnv
import RnNames
import RnHsDoc          ( rnHsDoc, rnMbLHsDoc )
import TcAnnotations    ( annCtxt )
import TcRnMonad

import ForeignCall      ( CCallTarget(..) )
import Module
import HscTypes         ( Warnings(..), plusWarns )
import Class            ( FunDep )
import PrelNames        ( isUnboundName )
import Name
import NameSet
import NameEnv
import Avail
import Outputable
import Bag
import BasicTypes       ( RuleName )
import FastString
import SrcLoc
import DynFlags
import HscTypes         ( HscEnv, hsc_dflags )
import ListSetOps       ( findDupsEq, removeDups )
import Digraph          ( SCC, flattenSCC, stronglyConnCompFromEdgedVertices )
import Util             ( mapSnd )

import Control.Monad
import Data.List( partition, sortBy )
import Data.Traversable (traverse)
import Maybes( orElse, mapMaybe )

-- Brings the binders of the group into scope in the appropriate places;
-- does NOT assume that anything is in scope already
rnSrcDecls :: [Name] -> HsGroup RdrName -> RnM (TcGblEnv, HsGroup Name)
-- Rename a HsGroup; used for normal source files *and* hs-boot files
rnSrcDecls extra_deps group@(HsGroup { hs_valds   = val_decls,
                                       hs_splcds  = splice_decls,
                                       hs_tyclds  = tycl_decls,
                                       hs_instds  = inst_decls,
                                       hs_derivds = deriv_decls,
                                       hs_fixds   = fix_decls,
                                       hs_warnds  = warn_decls,
                                       hs_annds   = ann_decls,
                                       hs_fords   = foreign_decls,
                                       hs_defds   = default_decls,
                                       hs_ruleds  = rule_decls,
                                       hs_vects   = vect_decls,
                                       hs_docs    = docs })
 = do {
   -- (A) Process the fixity declarations, creating a mapping from
   --     FastStrings to FixItems.
   --     Also checks for duplcates.
   local_fix_env <- makeMiniFixityEnv fix_decls ;

   -- (B) Bring top level binders (and their fixities) into scope,
   --     *except* for the value bindings, which get brought in below.
   --     However *do* include class ops, data constructors
   --     And for hs-boot files *do* include the value signatures
   (tc_envs, tc_bndrs) <- getLocalNonValBinders local_fix_env group ;
   setEnvs tc_envs $ do {

   failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations

   -- (C) Extract the mapping from data constructors to field names and
   --     extend the record field env.
   --     This depends on the data constructors and field names being in
   --     scope from (B) above
   inNewEnv (extendRecordFieldEnv tycl_decls inst_decls) $ \ _ -> do {

   -- (D) Rename the left-hand sides of the value bindings.
   --     This depends on everything from (B) being in scope,
   --     and on (C) for resolving record wild cards.
   --     It uses the fixity env from (A) to bind fixities for view patterns.
   new_lhs <- rnTopBindsLHS local_fix_env val_decls ;
   -- bind the LHSes (and their fixities) in the global rdr environment
   let { val_binders = collectHsValBinders new_lhs ;
         all_bndrs   = addListToNameSet tc_bndrs val_binders ;
         val_avails  = map Avail val_binders  } ;
   traceRn (text "rnSrcDecls" <+> ppr val_avails) ;
   (tcg_env, tcl_env) <- extendGlobalRdrEnvRn val_avails local_fix_env ;
   traceRn (ptext (sLit "Val binders") <+> (ppr val_binders)) ;
   setEnvs (tcg_env, tcl_env) $ do {

   --  Now everything is in scope, as the remaining renaming assumes.

   -- (E) Rename type and class decls
   --     (note that value LHSes need to be in scope for default methods)
   --
   -- You might think that we could build proper def/use information
   -- for type and class declarations, but they can be involved
   -- in mutual recursion across modules, and we only do the SCC
   -- analysis for them in the type checker.
   -- So we content ourselves with gathering uses only; that
   -- means we'll only report a declaration as unused if it isn't
   -- mentioned at all.  Ah well.
   traceRn (text "Start rnTyClDecls") ;
   (rn_tycl_decls, src_fvs1) <- rnTyClDecls extra_deps tycl_decls ;

   -- (F) Rename Value declarations right-hand sides
   traceRn (text "Start rnmono") ;
   (rn_val_decls, bind_dus) <- rnTopBindsRHS all_bndrs new_lhs ;
   traceRn (text "finish rnmono" <+> ppr rn_val_decls) ;

   -- (G) Rename Fixity and deprecations

   -- Rename fixity declarations and error if we try to
   -- fix something from another module (duplicates were checked in (A))
   rn_fix_decls <- rnSrcFixityDecls all_bndrs fix_decls ;

   -- Rename deprec decls;
   -- check for duplicates and ensure that deprecated things are defined locally
   -- at the moment, we don't keep these around past renaming
   rn_warns <- rnSrcWarnDecls all_bndrs warn_decls ;

   -- (H) Rename Everything else

   (rn_inst_decls,    src_fvs2) <- rnList rnSrcInstDecl   inst_decls ;
   (rn_rule_decls,    src_fvs3) <- setXOptM Opt_ScopedTypeVariables $
                                   rnList rnHsRuleDecl    rule_decls ;
                           -- Inside RULES, scoped type variables are on
   (rn_vect_decls,    src_fvs4) <- rnList rnHsVectDecl    vect_decls ;
   (rn_foreign_decls, src_fvs5) <- rnList rnHsForeignDecl foreign_decls ;
   (rn_ann_decls,     src_fvs6) <- rnList rnAnnDecl       ann_decls ;
   (rn_default_decls, src_fvs7) <- rnList rnDefaultDecl   default_decls ;
   (rn_deriv_decls,   src_fvs8) <- rnList rnSrcDerivDecl  deriv_decls ;
   (rn_splice_decls,  src_fvs9) <- rnList rnSpliceDecl    splice_decls ;
      -- Haddock docs; no free vars
   rn_docs <- mapM (wrapLocM rnDocDecl) docs ;

    last_tcg_env <- getGblEnv ;
   -- (I) Compute the results and return
   let {rn_group = HsGroup { hs_valds   = rn_val_decls,
                             hs_splcds  = rn_splice_decls,
                             hs_tyclds  = rn_tycl_decls,
                             hs_instds  = rn_inst_decls,
                             hs_derivds = rn_deriv_decls,
                             hs_fixds   = rn_fix_decls,
                             hs_warnds  = [], -- warns are returned in the tcg_env
                                             -- (see below) not in the HsGroup
                             hs_fords  = rn_foreign_decls,
                             hs_annds  = rn_ann_decls,
                             hs_defds  = rn_default_decls,
                             hs_ruleds = rn_rule_decls,
                             hs_vects  = rn_vect_decls,
                             hs_docs   = rn_docs } ;

        tycl_bndrs = hsTyClDeclsBinders rn_tycl_decls rn_inst_decls ;
        ford_bndrs = hsForeignDeclsBinders rn_foreign_decls ;
        other_def  = (Just (mkNameSet tycl_bndrs `unionNameSets` mkNameSet ford_bndrs), emptyNameSet) ;
        other_fvs  = plusFVs [src_fvs1, src_fvs2, src_fvs3, src_fvs4,
                              src_fvs5, src_fvs6, src_fvs7, src_fvs8,
                              src_fvs9] ;
                -- It is tiresome to gather the binders from type and class decls

        src_dus = [other_def] `plusDU` bind_dus `plusDU` usesOnly other_fvs ;
                -- Instance decls may have occurrences of things bound in bind_dus
                -- so we must put other_fvs last

        final_tcg_env = let tcg_env' = (last_tcg_env `addTcgDUs` src_dus)
                        in -- we return the deprecs in the env, not in the HsGroup above
                        tcg_env' { tcg_warns = tcg_warns tcg_env' `plusWarns` rn_warns };
       } ;

   traceRn (text "finish rnSrc" <+> ppr rn_group) ;
   traceRn (text "finish Dus" <+> ppr src_dus ) ;
   return (final_tcg_env, rn_group)
                    }}}}

-- some utils because we do this a bunch above
-- compute and install the new env
inNewEnv :: TcM TcGblEnv -> (TcGblEnv -> TcM a) -> TcM a
inNewEnv env cont = do e <- env
                       setGblEnv e $ cont e

addTcgDUs :: TcGblEnv -> DefUses -> TcGblEnv
-- This function could be defined lower down in the module hierarchy,
-- but there doesn't seem anywhere very logical to put it.
addTcgDUs tcg_env dus = tcg_env { tcg_dus = tcg_dus tcg_env `plusDU` dus }

rnList :: (a -> RnM (b, FreeVars)) -> [Located a] -> RnM ([Located b], FreeVars)
rnList f xs = mapFvRn (wrapLocFstM f) xs

rnDocDecl :: DocDecl -> RnM DocDecl
rnDocDecl (DocCommentNext doc) = do
  rn_doc <- rnHsDoc doc
  return (DocCommentNext rn_doc)
rnDocDecl (DocCommentPrev doc) = do
  rn_doc <- rnHsDoc doc
  return (DocCommentPrev rn_doc)
rnDocDecl (DocCommentNamed str doc) = do
  rn_doc <- rnHsDoc doc
  return (DocCommentNamed str rn_doc)
rnDocDecl (DocGroup lev doc) = do
  rn_doc <- rnHsDoc doc
  return (DocGroup lev rn_doc)

rnSrcFixityDecls :: NameSet -> [LFixitySig RdrName] -> RnM [LFixitySig Name]
-- Rename the fixity decls, so we can put
-- the renamed decls in the renamed syntax tree
-- Errors if the thing being fixed is not defined locally.
--
-- The returned FixitySigs are not actually used for anything,
-- except perhaps the GHCi API
rnSrcFixityDecls bndr_set fix_decls
  = do fix_decls <- mapM rn_decl fix_decls
       return (concat fix_decls)
  where
    sig_ctxt = TopSigCtxt bndr_set True
       -- True <=> can give fixity for class decls and record selectors

    rn_decl :: LFixitySig RdrName -> RnM [LFixitySig Name]
        -- GHC extension: look up both the tycon and data con
        -- for con-like things; hence returning a list
        -- If neither are in scope, report an error; otherwise
        -- return a fixity sig for each (slightly odd)
    rn_decl (L loc (FixitySig (L name_loc rdr_name) fixity))
      = setSrcSpan name_loc $
                    -- this lookup will fail if the definition isn't local
        do names <- lookupLocalTcNames sig_ctxt what rdr_name
           return [ L loc (FixitySig (L name_loc name) fixity)
                  | name <- names ]
    what = ptext (sLit "fixity signature")

-- checks that the deprecations are defined locally, and that there are no duplicates
rnSrcWarnDecls :: NameSet -> [LWarnDecl RdrName] -> RnM Warnings
rnSrcWarnDecls _ []
  = return NoWarnings

rnSrcWarnDecls bndr_set decls
  = do { -- check for duplicates
       ; mapM_ (\ dups -> let (L loc rdr:lrdr':_) = dups
                          in addErrAt loc (dupWarnDecl lrdr' rdr))
               warn_rdr_dups
       ; pairs_s <- mapM (addLocM rn_deprec) decls
       ; return (WarnSome ((concat pairs_s))) }
 where
   sig_ctxt = TopSigCtxt bndr_set True
      -- True <=> Can give deprecations for class ops and record sels

   rn_deprec (Warning rdr_name txt)
       -- ensures that the names are defined locally
     = do { names <- lookupLocalTcNames sig_ctxt what rdr_name
          ; return [(nameOccName name, txt) | name <- names] }

   what = ptext (sLit "deprecation")

   warn_rdr_dups = findDupRdrNames (map (\ (L loc (Warning rdr_name _)) -> L loc rdr_name) decls)

findDupRdrNames :: [Located RdrName] -> [[Located RdrName]]
findDupRdrNames = findDupsEq (\ x -> \ y -> rdrNameOcc (unLoc x) == rdrNameOcc (unLoc y))

-- look for duplicates among the OccNames;
-- we check that the names are defined above
-- invt: the lists returned by findDupsEq always have at least two elements

dupWarnDecl :: Located RdrName -> RdrName -> SDoc
-- Located RdrName -> DeprecDecl RdrName -> SDoc
dupWarnDecl (L loc _) rdr_name
  = vcat [ptext (sLit "Multiple warning declarations for") <+> quotes (ppr rdr_name),
          ptext (sLit "also at ") <+> ppr loc]

rnAnnDecl :: AnnDecl RdrName -> RnM (AnnDecl Name, FreeVars)
rnAnnDecl ann@(HsAnnotation provenance expr)
  = addErrCtxt (annCtxt ann) $
    do { (provenance', provenance_fvs) <- rnAnnProvenance provenance
       ; (expr', expr_fvs) <- setStage (Splice False) $
                              rnLExpr expr
       ; return (HsAnnotation provenance' expr', provenance_fvs `plusFV` expr_fvs) }

rnAnnProvenance :: AnnProvenance RdrName -> RnM (AnnProvenance Name, FreeVars)
rnAnnProvenance provenance = do
    provenance' <- traverse lookupTopBndrRn provenance
    return (provenance', maybe emptyFVs unitFV (annProvenanceName_maybe provenance'))

rnDefaultDecl :: DefaultDecl RdrName -> RnM (DefaultDecl Name, FreeVars)
rnDefaultDecl (DefaultDecl tys)
  = do { (tys', fvs) <- rnLHsTypes doc_str tys
       ; return (DefaultDecl tys', fvs) }
  where
    doc_str = DefaultDeclCtx

rnHsForeignDecl :: ForeignDecl RdrName -> RnM (ForeignDecl Name, FreeVars)
rnHsForeignDecl (ForeignImport name ty _ spec)
  = do { topEnv :: HscEnv <- getTopEnv
       ; name' <- lookupLocatedTopBndrRn name
       ; (ty', fvs) <- rnLHsType (ForeignDeclCtx name) ty

        -- Mark any PackageTarget style imports as coming from the current package
       ; let packageId = thisPackage $ hsc_dflags topEnv
             spec'     = patchForeignImport packageId spec

       ; return (ForeignImport name' ty' noForeignImportCoercionYet spec', fvs) }

rnHsForeignDecl (ForeignExport name ty _ spec)
  = do { name' <- lookupLocatedOccRn name
       ; (ty', fvs) <- rnLHsType (ForeignDeclCtx name) ty
       ; return (ForeignExport name' ty' noForeignExportCoercionYet spec, fvs `addOneFV` unLoc name') }
        -- NB: a foreign export is an *occurrence site* for name, so
        --     we add it to the free-variable list.  It might, for example,
        --     be imported from another module

-- | For Windows DLLs we need to know what packages imported symbols are from
--      to generate correct calls. Imported symbols are tagged with the current
--      package, so if they get inlined across a package boundry we'll still
--      know where they're from.
--
patchForeignImport :: PackageId -> ForeignImport -> ForeignImport
patchForeignImport packageId (CImport cconv safety fs spec)
        = CImport cconv safety fs (patchCImportSpec packageId spec)

patchCImportSpec :: PackageId -> CImportSpec -> CImportSpec
patchCImportSpec packageId spec
 = case spec of
        CFunction callTarget    -> CFunction $ patchCCallTarget packageId callTarget
        _                       -> spec

patchCCallTarget :: PackageId -> CCallTarget -> CCallTarget
patchCCallTarget packageId callTarget =
  case callTarget of
  StaticTarget label Nothing isFun -> StaticTarget label (Just packageId) isFun
  _                                -> callTarget

rnSrcInstDecl :: InstDecl RdrName -> RnM (InstDecl Name, FreeVars)
rnSrcInstDecl (TyFamInstD { tfid_inst = tfi }) 
  = do { (tfi', fvs) <- rnTyFamInstDecl Nothing tfi
       ; return (TyFamInstD { tfid_inst = tfi' }, fvs) }

rnSrcInstDecl (DataFamInstD { dfid_inst = dfi }) 
  = do { (dfi', fvs) <- rnDataFamInstDecl Nothing dfi
       ; return (DataFamInstD { dfid_inst = dfi' }, fvs) }

rnSrcInstDecl (ClsInstD { cid_inst = cid })
  = do { (cid', fvs) <- rnClsInstDecl cid
       ; return (ClsInstD { cid_inst = cid' }, fvs) }

rnClsInstDecl :: ClsInstDecl RdrName -> RnM (ClsInstDecl Name, FreeVars)
rnClsInstDecl (ClsInstDecl { cid_poly_ty = inst_ty, cid_binds = mbinds
                           , cid_sigs = uprags, cid_tyfam_insts = ats
                           , cid_datafam_insts = adts })
        -- Used for both source and interface file decls
  = do { (inst_ty', inst_fvs) <- rnLHsInstType (text "In an instance declaration") inst_ty
       ; case splitLHsInstDeclTy_maybe inst_ty' of {
           Nothing -> return (ClsInstDecl { cid_poly_ty = inst_ty', cid_binds = emptyLHsBinds
                                          , cid_sigs = [], cid_tyfam_insts = []
                                          , cid_datafam_insts = [] }
                             , inst_fvs) ;
           Just (inst_tyvars, _, L _ cls,_) ->

    do { let (spec_inst_prags, other_sigs) = partition isSpecInstLSig uprags
             ktv_names = hsLKiTyVarNames inst_tyvars

       -- Rename the associated types, and type signatures
       -- Both need to have the instance type variables in scope
       ; traceRn (text "rnSrcInstDecl"  <+> ppr inst_ty' $$ ppr inst_tyvars $$ ppr ktv_names)
       ; ((ats', adts', other_sigs'), more_fvs) 
             <- extendTyVarEnvFVRn ktv_names $
                do { (ats', at_fvs) <- rnATInstDecls rnTyFamInstDecl cls inst_tyvars ats
                   ; (adts', adt_fvs) <- rnATInstDecls rnDataFamInstDecl cls inst_tyvars adts
                   ; (other_sigs', sig_fvs) <- renameSigs (InstDeclCtxt cls) other_sigs
                   ; return ( (ats', adts', other_sigs')
                            , at_fvs `plusFV` adt_fvs `plusFV` sig_fvs) }

        -- Rename the bindings
        -- The typechecker (not the renamer) checks that all
        -- the bindings are for the right class
        -- (Slightly strangely) when scoped type variables are on, the
        -- forall-d tyvars scope over the method bindings too
       ; (mbinds', meth_fvs) <- extendTyVarEnvForMethodBinds ktv_names $
                                rnMethodBinds cls (mkSigTvFn other_sigs')
                                                  mbinds

        -- Rename the SPECIALISE instance pramas
        -- Annoyingly the type variables are not in scope here,
        -- so that      instance Eq a => Eq (T a) where
        --                      {-# SPECIALISE instance Eq a => Eq (T [a]) #-}
        -- works OK. That's why we did the partition game above
        --
       ; (spec_inst_prags', spec_inst_fvs)
             <- renameSigs (InstDeclCtxt cls) spec_inst_prags

       ; let uprags' = spec_inst_prags' ++ other_sigs'
             all_fvs = meth_fvs `plusFV` more_fvs
                          `plusFV` spec_inst_fvs
                          `plusFV` inst_fvs
       ; return (ClsInstDecl { cid_poly_ty = inst_ty', cid_binds = mbinds'
                             , cid_sigs = uprags', cid_tyfam_insts = ats'
                             , cid_datafam_insts = adts' },
                 all_fvs) } } }
             -- We return the renamed associated data type declarations so
             -- that they can be entered into the list of type declarations
             -- for the binding group, but we also keep a copy in the instance.
             -- The latter is needed for well-formedness checks in the type
             -- checker (eg, to ensure that all ATs of the instance actually
             -- receive a declaration).
             -- NB: Even the copies in the instance declaration carry copies of
             --     the instance context after renaming.  This is a bit
             --     strange, but should not matter (and it would be more work
             --     to remove the context).

rnFamInstDecl :: HsDocContext
              -> Maybe (Name, [Name])
              -> Located RdrName
              -> [LHsType RdrName]
              -> rhs
              -> (HsDocContext -> rhs -> RnM (rhs', FreeVars))
              -> RnM (Located Name, HsWithBndrs [LHsType Name], rhs', FreeVars)
rnFamInstDecl doc mb_cls tycon pats payload rnPayload
  = do { tycon'   <- lookupFamInstName (fmap fst mb_cls) tycon
       ; let loc = case pats of
                     []             -> pprPanic "rnFamInstDecl" (ppr tycon)
                     (L loc _ : []) -> loc
                     (L loc _ : ps) -> combineSrcSpans loc (getLoc (last ps))
             (kv_rdr_names, tv_rdr_names) = extractHsTysRdrTyVars pats


       ; rdr_env  <- getLocalRdrEnv
       ; kv_names <- mapM (newTyVarNameRn mb_cls rdr_env loc) kv_rdr_names
       ; tv_names <- mapM (newTyVarNameRn mb_cls rdr_env loc) tv_rdr_names
             -- All the free vars of the family patterns
             -- with a sensible binding location
       ; ((pats', payload'), fvs) 
              <- bindLocalNamesFV kv_names $ 
                 bindLocalNamesFV tv_names $ 
                 do { (pats', pat_fvs) <- rnLHsTypes doc pats
                    ; (payload', rhs_fvs) <- rnPayload doc payload

                         -- See Note [Renaming associated types]
                    ; let bad_tvs = case mb_cls of
                                      Nothing          -> []
                                      Just (_,cls_tvs) -> filter is_bad cls_tvs
                          is_bad tv = not (tv `elem` tv_names) && tv `elemNameSet` rhs_fvs

                    ; unless (null bad_tvs) (badAssocRhs bad_tvs)
                    ; return ((pats', payload'), rhs_fvs `plusFV` pat_fvs) }
                              

       ; let all_fvs = fvs `addOneFV` unLoc tycon'
       ; return (tycon',
                 HsWB { hswb_cts = pats', hswb_kvs = kv_names, hswb_tvs = tv_names },
                 payload',
                 all_fvs) }
             -- type instance => use, hence addOneFV

rnTyFamInstDecl :: Maybe (Name, [Name])
                -> TyFamInstDecl RdrName
                -> RnM (TyFamInstDecl Name, FreeVars)
rnTyFamInstDecl mb_cls (TyFamInstDecl { tfid_eqn = L loc eqn })
  = do { (eqn', fvs) <- rnTyFamInstEqn mb_cls eqn
       ; return (TyFamInstDecl { tfid_eqn = L loc eqn'
                               , tfid_fvs = fvs }, fvs) }

rnTyFamInstEqn :: Maybe (Name, [Name])
               -> TyFamInstEqn RdrName
               -> RnM (TyFamInstEqn Name, FreeVars)
rnTyFamInstEqn mb_cls (TyFamInstEqn { tfie_tycon = tycon
                                    , tfie_pats  = HsWB { hswb_cts = pats }
                                    , tfie_rhs   = rhs })
  = do { (tycon', pats', rhs', fvs) <-
           rnFamInstDecl (TySynCtx tycon) mb_cls tycon pats rhs rnTySyn
       ; return (TyFamInstEqn { tfie_tycon = tycon'
                              , tfie_pats  = pats'
                              , tfie_rhs   = rhs' }, fvs) }

rnDataFamInstDecl :: Maybe (Name, [Name])
                  -> DataFamInstDecl RdrName
                  -> RnM (DataFamInstDecl Name, FreeVars)
rnDataFamInstDecl mb_cls (DataFamInstDecl { dfid_tycon = tycon
                                          , dfid_pats  = HsWB { hswb_cts = pats }
                                          , dfid_defn  = defn })
  = do { (tycon', pats', defn', fvs) <-
           rnFamInstDecl (TyDataCtx tycon) mb_cls tycon pats defn rnDataDefn
       ; return (DataFamInstDecl { dfid_tycon = tycon'
                                 , dfid_pats  = pats'
                                 , dfid_defn  = defn'
                                 , dfid_fvs   = fvs }, fvs) }

-- rename associated type family decl in class
rnATDecls :: Name      -- Class
          -> [LFamilyDecl RdrName] 
          -> RnM ([LFamilyDecl Name], FreeVars)
rnATDecls cls at_decls
  = rnList (rnFamDecl (Just cls)) at_decls

rnATInstDecls :: (Maybe (Name, [Name]) ->    -- The function that renames
                  decl RdrName ->            -- an instance. rnTyFamInstDecl
                  RnM (decl Name, FreeVars)) -- or rnDataFamInstDecl
              -> Name      -- Class
              -> LHsTyVarBndrs Name
              -> [Located (decl RdrName)] 
              -> RnM ([Located (decl Name)], FreeVars)
-- Used for data and type family defaults in a class decl
-- and the family instance declarations in an instance
--
-- NB: We allow duplicate associated-type decls;
--     See Note [Associated type instances] in TcInstDcls
rnATInstDecls rnFun cls hs_tvs at_insts
  = rnList (rnFun (Just (cls, tv_ns))) at_insts
  where
    tv_ns = hsLTyVarNames hs_tvs
    -- Type variable binders (but NOT kind variables)
    -- See Note [Renaming associated types] in RnTypes

extendTyVarEnvForMethodBinds :: [Name]
                             -> RnM (LHsBinds Name, FreeVars)
                             -> RnM (LHsBinds Name, FreeVars)
extendTyVarEnvForMethodBinds ktv_names thing_inside
  = do  { scoped_tvs <- xoptM Opt_ScopedTypeVariables
        ; if scoped_tvs then
                extendTyVarEnvFVRn ktv_names thing_inside
          else
                thing_inside }

rnSrcDerivDecl :: DerivDecl RdrName -> RnM (DerivDecl Name, FreeVars)
rnSrcDerivDecl (DerivDecl ty)
  = do { standalone_deriv_ok <- xoptM Opt_StandaloneDeriving
       ; unless standalone_deriv_ok (addErr standaloneDerivErr)
       ; (ty', fvs) <- rnLHsInstType (text "In a deriving declaration") ty
       ; return (DerivDecl ty', fvs) }

standaloneDerivErr :: SDoc
standaloneDerivErr
  = hang (ptext (sLit "Illegal standalone deriving declaration"))
       2 (ptext (sLit "Use StandaloneDeriving to enable this extension"))

rnHsRuleDecl :: RuleDecl RdrName -> RnM (RuleDecl Name, FreeVars)
rnHsRuleDecl (HsRule rule_name act vars lhs _fv_lhs rhs _fv_rhs)
  = do { let rdr_names_w_loc = map get_var vars
       ; checkDupRdrNames rdr_names_w_loc
       ; checkShadowedRdrNames rdr_names_w_loc
       ; names <- newLocalBndrsRn rdr_names_w_loc
       ; bindHsRuleVars rule_name vars names $ \ vars' ->
    do { (lhs', fv_lhs') <- rnLExpr lhs
       ; (rhs', fv_rhs') <- rnLExpr rhs
       ; checkValidRule rule_name names lhs' fv_lhs'
       ; return (HsRule rule_name act vars' lhs' fv_lhs' rhs' fv_rhs',
                 fv_lhs' `plusFV` fv_rhs') } }
  where
    get_var (RuleBndrSig v _) = v
    get_var (RuleBndr v) = v

bindHsRuleVars :: RuleName -> [RuleBndr RdrName] -> [Name]
               -> ([RuleBndr Name] -> RnM (a, FreeVars))
               -> RnM (a, FreeVars)
bindHsRuleVars rule_name vars names thing_inside
  = go vars names $ \ vars' ->
    bindLocalNamesFV names (thing_inside vars')
  where
    doc = RuleCtx rule_name

    go (RuleBndr (L loc _) : vars) (n : ns) thing_inside
      = go vars ns $ \ vars' ->
        thing_inside (RuleBndr (L loc n) : vars')

    go (RuleBndrSig (L loc _) bsig : vars) (n : ns) thing_inside
      = rnHsBndrSig doc bsig $ \ bsig' ->
        go vars ns $ \ vars' ->
        thing_inside (RuleBndrSig (L loc n) bsig' : vars')

    go [] [] thing_inside = thing_inside []
    go vars names _ = pprPanic "bindRuleVars" (ppr vars $$ ppr names)

checkValidRule :: FastString -> [Name] -> LHsExpr Name -> NameSet -> RnM ()
checkValidRule rule_name ids lhs' fv_lhs'
  = do  {       -- Check for the form of the LHS
          case (validRuleLhs ids lhs') of
                Nothing  -> return ()
                Just bad -> failWithTc (badRuleLhsErr rule_name lhs' bad)

                -- Check that LHS vars are all bound
        ; let bad_vars = [var | var <- ids, not (var `elemNameSet` fv_lhs')]
        ; mapM_ (addErr . badRuleVar rule_name) bad_vars }

validRuleLhs :: [Name] -> LHsExpr Name -> Maybe (HsExpr Name)
-- Nothing => OK
-- Just e  => Not ok, and e is the offending expression
validRuleLhs foralls lhs
  = checkl lhs
  where
    checkl (L _ e) = check e

    check (OpApp e1 op _ e2)              = checkl op `mplus` checkl_e e1 `mplus` checkl_e e2
    check (HsApp e1 e2)                   = checkl e1 `mplus` checkl_e e2
    check (HsVar v) | v `notElem` foralls = Nothing
    check other                           = Just other  -- Failure

        -- Check an argument
    checkl_e (L _ _e) = Nothing         -- Was (check_e e); see Note [Rule LHS validity checking]

{-      Commented out; see Note [Rule LHS validity checking] above
    check_e (HsVar v)     = Nothing
    check_e (HsPar e)     = checkl_e e
    check_e (HsLit e)     = Nothing
    check_e (HsOverLit e) = Nothing

    check_e (OpApp e1 op _ e2)   = checkl_e e1 `mplus` checkl_e op `mplus` checkl_e e2
    check_e (HsApp e1 e2)        = checkl_e e1 `mplus` checkl_e e2
    check_e (NegApp e _)         = checkl_e e
    check_e (ExplicitList _ es)  = checkl_es es
    check_e other                = Just other   -- Fails

    checkl_es es = foldr (mplus . checkl_e) Nothing es
-}

badRuleVar :: FastString -> Name -> SDoc
badRuleVar name var
  = sep [ptext (sLit "Rule") <+> doubleQuotes (ftext name) <> colon,
         ptext (sLit "Forall'd variable") <+> quotes (ppr var) <+>
                ptext (sLit "does not appear on left hand side")]

badRuleLhsErr :: FastString -> LHsExpr Name -> HsExpr Name -> SDoc
badRuleLhsErr name lhs bad_e
  = sep [ptext (sLit "Rule") <+> ftext name <> colon,
         nest 4 (vcat [ptext (sLit "Illegal expression:") <+> ppr bad_e,
                       ptext (sLit "in left-hand side:") <+> ppr lhs])]
    $$
    ptext (sLit "LHS must be of form (f e1 .. en) where f is not forall'd")

rnHsVectDecl :: VectDecl RdrName -> RnM (VectDecl Name, FreeVars)
-- FIXME: For the moment, the right-hand side is restricted to be a variable as we cannot properly
--        typecheck a complex right-hand side without invoking 'vectType' from the vectoriser.
rnHsVectDecl (HsVect var rhs@(L _ (HsVar _)))
  = do { var' <- lookupLocatedOccRn var
       ; (rhs', fv_rhs) <- rnLExpr rhs
       ; return (HsVect var' rhs', fv_rhs `addOneFV` unLoc var')
       }
rnHsVectDecl (HsVect _var _rhs)
  = failWith $ vcat 
               [ ptext (sLit "IMPLEMENTATION RESTRICTION: right-hand side of a VECTORISE pragma")
               , ptext (sLit "must be an identifier")
               ]
rnHsVectDecl (HsNoVect var)
  = do { var' <- lookupLocatedTopBndrRn var           -- only applies to local (not imported) names
       ; return (HsNoVect var', unitFV (unLoc var'))
       }
rnHsVectDecl (HsVectTypeIn isScalar tycon Nothing)
  = do { tycon' <- lookupLocatedOccRn tycon
       ; return (HsVectTypeIn isScalar tycon' Nothing, unitFV (unLoc tycon'))
       }
rnHsVectDecl (HsVectTypeIn isScalar tycon (Just rhs_tycon))
  = do { tycon'     <- lookupLocatedOccRn tycon
       ; rhs_tycon' <- lookupLocatedOccRn rhs_tycon
       ; return ( HsVectTypeIn isScalar tycon' (Just rhs_tycon')
                , mkFVs [unLoc tycon', unLoc rhs_tycon'])
       }
rnHsVectDecl (HsVectTypeOut _ _ _)
  = panic "RnSource.rnHsVectDecl: Unexpected 'HsVectTypeOut'"
rnHsVectDecl (HsVectClassIn cls)
  = do { cls' <- lookupLocatedOccRn cls
       ; return (HsVectClassIn cls', unitFV (unLoc cls'))
       }
rnHsVectDecl (HsVectClassOut _)
  = panic "RnSource.rnHsVectDecl: Unexpected 'HsVectClassOut'"
rnHsVectDecl (HsVectInstIn instTy)
  = do { (instTy', fvs) <- rnLHsInstType (text "In a VECTORISE pragma") instTy
       ; return (HsVectInstIn instTy', fvs)
       }
rnHsVectDecl (HsVectInstOut _)
  = panic "RnSource.rnHsVectDecl: Unexpected 'HsVectInstOut'"

isInPackage :: PackageId -> Name -> Bool
isInPackage pkgId nm = case nameModule_maybe nm of
                         Nothing -> False
                         Just m  -> pkgId == modulePackageId m
-- We use nameModule_maybe because we might be in a TH splice, in which case
-- there is no module name. In that case we cannot have mutual dependencies,
-- so it's fine to return False here.

rnTyClDecls :: [Name] -> [TyClGroup RdrName]
            -> RnM ([TyClGroup Name], FreeVars)
-- Rename the declarations and do depedency analysis on them
rnTyClDecls extra_deps tycl_ds
  = do { ds_w_fvs <- mapM (wrapLocFstM rnTyClDecl) (tyClGroupConcat tycl_ds)
       ; role_annot_env <- rnRoleAnnots (concatMap group_roles tycl_ds)
       ; thisPkg  <- fmap thisPackage getDynFlags
       ; let add_boot_deps :: FreeVars -> FreeVars
             -- See Note [Extra dependencies from .hs-boot files]
             add_boot_deps fvs | any (isInPackage thisPkg) (nameSetToList fvs)
                               = fvs `plusFV` mkFVs extra_deps
                               | otherwise
                               = fvs

             ds_w_fvs' = mapSnd add_boot_deps ds_w_fvs

             sccs :: [SCC (LTyClDecl Name)]
             sccs = depAnalTyClDecls ds_w_fvs'

             all_fvs = foldr (plusFV . snd) emptyFVs ds_w_fvs'

             raw_groups = map flattenSCC sccs
             -- See Note [Role annotations in the renamer]
             (groups, orphan_roles)
               = foldr (\group (groups_acc, orphans_acc) ->
                         let names = map (tcdName . unLoc) group
                             roles = mapMaybe (lookupNameEnv orphans_acc) names
                             orphans' = delListFromNameEnv orphans_acc names
                              -- there doesn't seem to be an interface to
                              -- do the above more efficiently
                         in ( TyClGroup { group_tyclds = group
                                        , group_roles  = roles } : groups_acc
                            , orphans' )
                       )
                       ([], role_annot_env)
                       raw_groups
                 
       ; mapM_ orphanRoleAnnotErr (nameEnvElts orphan_roles)
       ; traceRn (text "rnTycl"  <+> (ppr ds_w_fvs $$ ppr sccs))
       ; return (groups, all_fvs) }

rnTyClDecl :: TyClDecl RdrName 
           -> RnM (TyClDecl Name, FreeVars)
rnTyClDecl (ForeignType {tcdLName = name, tcdExtName = ext_name})
  = do { name' <- lookupLocatedTopBndrRn name
       ; return (ForeignType {tcdLName = name', tcdExtName = ext_name},
                 emptyFVs) }

-- All flavours of type family declarations ("type family", "newtype family",
-- and "data family"), both top level and (for an associated type)
-- in a class decl
rnTyClDecl (FamDecl { tcdFam = decl })
  = do { (decl', fvs) <- rnFamDecl Nothing decl
       ; return (FamDecl decl', fvs) }

rnTyClDecl (SynDecl { tcdLName = tycon, tcdTyVars = tyvars, tcdRhs = rhs })
  = do { tycon' <- lookupLocatedTopBndrRn tycon
       ; let kvs = fst (extractHsTyRdrTyVars rhs)
             doc = TySynCtx tycon
       ; traceRn (text "rntycl-ty" <+> ppr tycon <+> ppr kvs)
       ; ((tyvars', rhs'), fvs) <- bindHsTyVars doc Nothing kvs tyvars $
                                    \ tyvars' ->
                                    do { (rhs', fvs) <- rnTySyn doc rhs
                                       ; return ((tyvars', rhs'), fvs) }
       ; return (SynDecl { tcdLName = tycon', tcdTyVars = tyvars'
                        , tcdRhs = rhs', tcdFVs = fvs }, fvs) }

-- "data", "newtype" declarations
-- both top level and (for an associated type) in an instance decl
rnTyClDecl (DataDecl { tcdLName = tycon, tcdTyVars = tyvars, tcdDataDefn = defn })
  = do { tycon' <- lookupLocatedTopBndrRn tycon
       ; let kvs = extractDataDefnKindVars defn
             doc = TyDataCtx tycon
       ; traceRn (text "rntycl-data" <+> ppr tycon <+> ppr kvs)
       ; ((tyvars', defn'), fvs) <- bindHsTyVars doc Nothing kvs tyvars $ \ tyvars' ->
                                    do { (defn', fvs) <- rnDataDefn doc defn
                                       ; return ((tyvars', defn'), fvs) }
       ; return (DataDecl { tcdLName = tycon', tcdTyVars = tyvars'
                          , tcdDataDefn = defn', tcdFVs = fvs }, fvs) }

rnTyClDecl (ClassDecl {tcdCtxt = context, tcdLName = lcls, 
                              tcdTyVars = tyvars, tcdFDs = fds, tcdSigs = sigs, 
                              tcdMeths = mbinds, tcdATs = ats, tcdATDefs = at_defs,
                              tcdDocs = docs})
  = do  { lcls' <- lookupLocatedTopBndrRn lcls
        ; let cls' = unLoc lcls'
              kvs = []  -- No scoped kind vars except those in
                        -- kind signatures on the tyvars

        -- Tyvars scope over superclass context and method signatures
        ; ((tyvars', context', fds', ats', at_defs', sigs'), stuff_fvs)
            <- bindHsTyVars cls_doc Nothing kvs tyvars $ \ tyvars' -> do
                  -- Checks for distinct tyvars
             { (context', cxt_fvs) <- rnContext cls_doc context
             ; fds'  <- rnFds (docOfHsDocContext cls_doc) fds
                         -- The fundeps have no free variables
             ; (ats',     fv_ats)     <- rnATDecls cls' ats
             ; (at_defs', fv_at_defs) <- rnATInstDecls rnTyFamInstDecl cls' tyvars' at_defs
             ; (sigs', sig_fvs) <- renameSigs (ClsDeclCtxt cls') sigs
             ; let fvs = cxt_fvs     `plusFV`
                         sig_fvs     `plusFV`
                         fv_ats      `plusFV`
                         fv_at_defs
             ; return ((tyvars', context', fds', ats', at_defs', sigs'), fvs) }

        -- No need to check for duplicate associated type decls
        -- since that is done by RnNames.extendGlobalRdrEnvRn

        -- Check the signatures
        -- First process the class op sigs (op_sigs), then the fixity sigs (non_op_sigs).
        ; let sig_rdr_names_w_locs = [op | L _ (TypeSig ops _) <- sigs, op <- ops]
        ; checkDupRdrNames sig_rdr_names_w_locs
                -- Typechecker is responsible for checking that we only
                -- give default-method bindings for things in this class.
                -- The renamer *could* check this for class decls, but can't
                -- for instance decls.

        -- The newLocals call is tiresome: given a generic class decl
        --      class C a where
        --        op :: a -> a
        --        op {| x+y |} (Inl a) = ...
        --        op {| x+y |} (Inr b) = ...
        --        op {| a*b |} (a*b)   = ...
        -- we want to name both "x" tyvars with the same unique, so that they are
        -- easy to group together in the typechecker.
        ; (mbinds', meth_fvs)
            <- extendTyVarEnvForMethodBinds (hsLKiTyVarNames tyvars') $
                -- No need to check for duplicate method signatures
                -- since that is done by RnNames.extendGlobalRdrEnvRn
                -- and the methods are already in scope
                 rnMethodBinds cls' (mkSigTvFn sigs') mbinds

  -- Haddock docs
        ; docs' <- mapM (wrapLocM rnDocDecl) docs

        ; let all_fvs = meth_fvs `plusFV` stuff_fvs
        ; return (ClassDecl { tcdCtxt = context', tcdLName = lcls',
                              tcdTyVars = tyvars', tcdFDs = fds', tcdSigs = sigs',
                              tcdMeths = mbinds', tcdATs = ats', tcdATDefs = at_defs',
                              tcdDocs = docs', tcdFVs = all_fvs },
                  all_fvs ) }
  where
    cls_doc  = ClassDeclCtx lcls

-- "type" and "type instance" declarations
rnTySyn :: HsDocContext -> LHsType RdrName -> RnM (LHsType Name, FreeVars)
rnTySyn doc rhs = rnLHsType doc rhs

-- Renames role annotations, returning them as the values in a NameEnv
-- and checks for duplicate role annotations.
-- It is quite convenient to do both of these in the same place.
-- See also Note [Role annotations in the renamer]
rnRoleAnnots :: [LRoleAnnotDecl RdrName]
                -> RnM (NameEnv (LRoleAnnotDecl Name))
rnRoleAnnots role_annots
  = do {  -- check for duplicates *before* renaming, to avoid lumping
          -- together all the unboundNames
         let (no_dups, dup_annots) = removeDups role_annots_cmp role_annots
             role_annots_cmp (L _ annot1) (L _ annot2)
               = roleAnnotDeclName annot1 `compare` roleAnnotDeclName annot2
       ; mapM_ dupRoleAnnotErr dup_annots
       ; role_annots' <- mapM (wrapLocM rn_role_annot1) no_dups
          -- some of the role annots will be unbound; we don't wish
          -- to include these
       ; return $ mkNameEnv [ (name, ra)
                            | ra <- role_annots'
                            , let name = roleAnnotDeclName (unLoc ra)
                            , not (isUnboundName name) ] }
  where
    rn_role_annot1 (RoleAnnotDecl tycon roles)
      = do {  -- the name is an *occurrence*
             tycon' <- wrapLocM lookupGlobalOccRn tycon
           ; return $ RoleAnnotDecl tycon' roles }

dupRoleAnnotErr :: [LRoleAnnotDecl RdrName] -> RnM ()
dupRoleAnnotErr [] = panic "dupRoleAnnotErr"
dupRoleAnnotErr list
  = addErrAt loc $
    hang (text "Duplicate role annotations for" <+>
          quotes (ppr $ roleAnnotDeclName first_decl) <> colon)
       2 (vcat $ map pp_role_annot sorted_list)
    where
      sorted_list = sortBy cmp_annot list
      (L loc first_decl : _) = sorted_list
    
      pp_role_annot (L loc decl) = hang (ppr decl)
                                      4 (text "-- written at" <+> ppr loc)

      cmp_annot (L loc1 _) (L loc2 _) = loc1 `compare` loc2

orphanRoleAnnotErr :: LRoleAnnotDecl Name -> RnM ()
orphanRoleAnnotErr (L loc decl)
  = addErrAt loc $
    hang (text "Role annotation for a type previously declared:")
       2 (ppr decl) $$
    parens (text "The role annotation must be given where" <+>
            quotes (ppr $ roleAnnotDeclName decl) <+>
            text "is declared.")

rnDataDefn :: HsDocContext -> HsDataDefn RdrName -> RnM (HsDataDefn Name, FreeVars)
rnDataDefn doc (HsDataDefn { dd_ND = new_or_data, dd_cType = cType
                           , dd_ctxt = context, dd_cons = condecls 
                           , dd_kindSig = sig, dd_derivs = derivs })
  = do  { checkTc (h98_style || null (unLoc context)) 
                  (badGadtStupidTheta doc)

        ; (sig', sig_fvs)  <- rnLHsMaybeKind doc sig
        ; (context', fvs1) <- rnContext doc context
        ; (derivs',  fvs3) <- rn_derivs derivs

        -- For the constructor declarations, drop the LocalRdrEnv
        -- in the GADT case, where the type variables in the declaration
        -- do not scope over the constructor signatures
        -- data T a where { T1 :: forall b. b-> b }
        ; let { zap_lcl_env | h98_style = \ thing -> thing
                            | otherwise = setLocalRdrEnv emptyLocalRdrEnv }
        ; (condecls', con_fvs) <- zap_lcl_env $
                                  rnConDecls condecls
           -- No need to check for duplicate constructor decls
           -- since that is done by RnNames.extendGlobalRdrEnvRn

        ; let all_fvs = fvs1 `plusFV` fvs3 `plusFV`
                        con_fvs `plusFV` sig_fvs
        ; return ( HsDataDefn { dd_ND = new_or_data, dd_cType = cType
                              , dd_ctxt = context', dd_kindSig = sig'
                              , dd_cons = condecls', dd_derivs = derivs' }
                 , all_fvs )
        }
  where
    h98_style = case condecls of         -- Note [Stupid theta]
                     L _ (ConDecl { con_res = ResTyGADT {} }) : _  -> False
                     _                                             -> True

    rn_derivs Nothing   = return (Nothing, emptyFVs)
    rn_derivs (Just ds) = do { (ds', fvs) <- rnLHsTypes doc ds
                             ; return (Just ds', fvs) }

badGadtStupidTheta :: HsDocContext -> SDoc
badGadtStupidTheta _
  = vcat [ptext (sLit "No context is allowed on a GADT-style data declaration"),
          ptext (sLit "(You can put a context on each contructor, though.)")]

rnFamDecl :: Maybe Name
                    -- Just cls => this FamilyDecl is nested 
                    --             inside an *class decl* for cls
                    --             used for associated types
          -> FamilyDecl RdrName
          -> RnM (FamilyDecl Name, FreeVars)
rnFamDecl mb_cls (FamilyDecl { fdLName = tycon, fdTyVars = tyvars
                             , fdInfo = info, fdKindSig = kind })
  = do { ((tycon', tyvars', kind'), fv1) <-
           bindHsTyVars fmly_doc mb_cls kvs tyvars $ \tyvars' ->
           do { tycon' <- lookupLocatedTopBndrRn tycon
              ; (kind', fv_kind) <- rnLHsMaybeKind fmly_doc kind
              ; return ((tycon', tyvars', kind'), fv_kind) }
       ; (info', fv2) <- rn_info info
       ; return (FamilyDecl { fdLName = tycon', fdTyVars = tyvars'
                            , fdInfo = info', fdKindSig = kind' }
                , fv1 `plusFV` fv2) }
  where 
     fmly_doc = TyFamilyCtx tycon
     kvs = extractRdrKindSigVars kind

     rn_info (ClosedTypeFamily eqns)
       = do { (eqns', fvs) <- rnList (rnTyFamInstEqn Nothing) eqns
                                                    -- no class context,
            ; return (ClosedTypeFamily eqns', fvs) }
     rn_info OpenTypeFamily = return (OpenTypeFamily, emptyFVs)
     rn_info DataFamily     = return (DataFamily, emptyFVs)
     

depAnalTyClDecls :: [(LTyClDecl Name, FreeVars)] -> [SCC (LTyClDecl Name)]
-- See Note [Dependency analysis of type and class decls]
depAnalTyClDecls ds_w_fvs
  = stronglyConnCompFromEdgedVertices edges
  where
    edges = [ (d, tcdName (unLoc d), map get_parent (nameSetToList fvs))
            | (d, fvs) <- ds_w_fvs ]

    -- We also need to consider data constructor names since
    -- they may appear in types because of promotion.
    get_parent n = lookupNameEnv assoc_env n `orElse` n

    assoc_env :: NameEnv Name   -- Maps a data constructor back
                                -- to its parent type constructor
    assoc_env = mkNameEnv assoc_env_list
    assoc_env_list = do
      (L _ d, _) <- ds_w_fvs
      case d of
        ClassDecl { tcdLName = L _ cls_name
                  , tcdATs = ats } 
          -> do L _ (FamilyDecl { fdLName = L _ fam_name }) <- ats
                return (fam_name, cls_name)
        DataDecl { tcdLName = L _ data_name
                 , tcdDataDefn = HsDataDefn { dd_cons = cons } } 
          -> do L _ dc <- cons
                return (unLoc (con_name dc), data_name)
        _ -> []

---------------
badAssocRhs :: [Name] -> RnM ()
badAssocRhs ns
  = addErr (hang (ptext (sLit "The RHS of an associated type declaration mentions type variable")
                  <> plural ns
                  <+> pprWithCommas (quotes . ppr) ns)
               2 (ptext (sLit "All such variables must be bound on the LHS")))

-----------------
rnConDecls :: [LConDecl RdrName] -> RnM ([LConDecl Name], FreeVars)
rnConDecls = mapFvRn (wrapLocFstM rnConDecl)

rnConDecl :: ConDecl RdrName -> RnM (ConDecl Name, FreeVars)
rnConDecl decl@(ConDecl { con_name = name, con_qvars = tvs
                        , con_cxt = lcxt@(L loc cxt), con_details = details
                        , con_res = res_ty, con_doc = mb_doc
                        , con_old_rec = old_rec, con_explicit = expl })
  = do  { addLocM checkConName name
        ; when old_rec (addWarn (deprecRecSyntax decl))
        ; new_name <- lookupLocatedTopBndrRn name

           -- For H98 syntax, the tvs are the existential ones
           -- For GADT syntax, the tvs are all the quantified tyvars
           -- Hence the 'filter' in the ResTyH98 case only
        ; rdr_env <- getLocalRdrEnv
        ; let arg_tys    = hsConDeclArgTys details
              (free_kvs, free_tvs) = case res_ty of
                                     ResTyH98 -> filterInScope rdr_env (get_rdr_tvs arg_tys)
                                     ResTyGADT ty -> get_rdr_tvs (ty : arg_tys)

         -- With an Explicit forall, check for unused binders
         -- With Implicit, find the mentioned ones, and use them as binders
        ; new_tvs <- case expl of
                       Implicit -> return (mkHsQTvs (userHsTyVarBndrs loc free_tvs))
                       Explicit -> do { warnUnusedForAlls (docOfHsDocContext doc) tvs free_tvs
                                      ; return tvs }

        ; mb_doc' <- rnMbLHsDoc mb_doc

        ; bindHsTyVars doc Nothing free_kvs new_tvs $ \new_tyvars -> do
        { (new_context, fvs1) <- rnContext doc lcxt
        ; (new_details, fvs2) <- rnConDeclDetails doc details
        ; (new_details', new_res_ty, fvs3) <- rnConResult doc (unLoc new_name) new_details res_ty
        ; return (decl { con_name = new_name, con_qvars = new_tyvars, con_cxt = new_context
                       , con_details = new_details', con_res = new_res_ty, con_doc = mb_doc' },
                  fvs1 `plusFV` fvs2 `plusFV` fvs3) }}
 where
    doc = ConDeclCtx name
    get_rdr_tvs tys = extractHsTysRdrTyVars (cxt ++ tys)

rnConResult :: HsDocContext -> Name
            -> HsConDetails (LHsType Name) [ConDeclField Name]
            -> ResType (LHsType RdrName)
            -> RnM (HsConDetails (LHsType Name) [ConDeclField Name],
                    ResType (LHsType Name), FreeVars)
rnConResult _   _   details ResTyH98 = return (details, ResTyH98, emptyFVs)
rnConResult doc con details (ResTyGADT ty)
  = do { (ty', fvs) <- rnLHsType doc ty
       ; let (arg_tys, res_ty) = splitHsFunType ty'
                -- We can finally split it up,
                -- now the renamer has dealt with fixities
                -- See Note [Sorting out the result type] in RdrHsSyn

       ; case details of
           InfixCon {}  -> pprPanic "rnConResult" (ppr ty)
           -- See Note [Sorting out the result type] in RdrHsSyn

           RecCon {}    -> do { unless (null arg_tys)
                                       (addErr (badRecResTy (docOfHsDocContext doc)))
                              ; return (details, ResTyGADT res_ty, fvs) }

           PrefixCon {} | isSymOcc (getOccName con)  -- See Note [Infix GADT cons]
                        , [ty1,ty2] <- arg_tys
                        -> do { fix_env <- getFixityEnv
                              ; return (if   con `elemNameEnv` fix_env
                                        then InfixCon ty1 ty2
                                        else PrefixCon arg_tys
                                       , ResTyGADT res_ty, fvs) }
                        | otherwise
                        -> return (PrefixCon arg_tys, ResTyGADT res_ty, fvs) }

rnConDeclDetails :: HsDocContext
                 -> HsConDetails (LHsType RdrName) [ConDeclField RdrName]
                 -> RnM (HsConDetails (LHsType Name) [ConDeclField Name], FreeVars)
rnConDeclDetails doc (PrefixCon tys)
  = do { (new_tys, fvs) <- rnLHsTypes doc tys
       ; return (PrefixCon new_tys, fvs) }

rnConDeclDetails doc (InfixCon ty1 ty2)
  = do { (new_ty1, fvs1) <- rnLHsType doc ty1
       ; (new_ty2, fvs2) <- rnLHsType doc ty2
       ; return (InfixCon new_ty1 new_ty2, fvs1 `plusFV` fvs2) }

rnConDeclDetails doc (RecCon fields)
  = do  { (new_fields, fvs) <- rnConDeclFields doc fields
                -- No need to check for duplicate fields
                -- since that is done by RnNames.extendGlobalRdrEnvRn
        ; return (RecCon new_fields, fvs) }

-------------------------------------------------
deprecRecSyntax :: ConDecl RdrName -> SDoc
deprecRecSyntax decl
  = vcat [ ptext (sLit "Declaration of") <+> quotes (ppr (con_name decl))
                 <+> ptext (sLit "uses deprecated syntax")
         , ptext (sLit "Instead, use the form")
         , nest 2 (ppr decl) ]   -- Pretty printer uses new form

badRecResTy :: SDoc -> SDoc
badRecResTy doc = ptext (sLit "Malformed constructor signature") $$ doc

extendRecordFieldEnv :: [TyClGroup RdrName] -> [LInstDecl RdrName] -> TcM TcGblEnv
extendRecordFieldEnv tycl_decls inst_decls
  = do  { tcg_env <- getGblEnv
        ; field_env' <- foldrM get_con (tcg_field_env tcg_env) all_data_cons
        ; return (tcg_env { tcg_field_env = field_env' }) }
  where
    -- we want to lookup:
    --  (a) a datatype constructor
    --  (b) a record field
    -- knowing that they're from this module.
    -- lookupLocatedTopBndrRn does this, because it does a lookupGreLocalRn_maybe,
    -- which keeps only the local ones.
    lookup x = do { x' <- lookupLocatedTopBndrRn x
                    ; return $ unLoc x'}

    all_data_cons :: [ConDecl RdrName]
    all_data_cons = [con | HsDataDefn { dd_cons = cons } <- all_ty_defs
                         , L _ con <- cons ]
    all_ty_defs = [ defn | L _ (DataDecl { tcdDataDefn = defn }) <- tyClGroupConcat tycl_decls ]
               ++ map dfid_defn (instDeclDataFamInsts inst_decls)  -- Do not forget associated types!

    get_con (ConDecl { con_name = con, con_details = RecCon flds })
            (RecFields env fld_set)
        = do { con' <- lookup con
             ; flds' <- mapM lookup (map cd_fld_name flds)
             ; let env'    = extendNameEnv env con' flds'
                   fld_set' = addListToNameSet fld_set flds'
             ; return $ (RecFields env' fld_set') }
    get_con _ env = return env

rnFds :: SDoc -> [Located (FunDep RdrName)] -> RnM [Located (FunDep Name)]

rnFds doc fds
  = mapM (wrapLocM rn_fds) fds
  where
    rn_fds (tys1, tys2)
      = do { tys1' <- rnHsTyVars doc tys1
           ; tys2' <- rnHsTyVars doc tys2
           ; return (tys1', tys2') }

rnHsTyVars :: SDoc -> [RdrName] -> RnM [Name]
rnHsTyVars doc tvs  = mapM (rnHsTyVar doc) tvs

rnHsTyVar :: SDoc -> RdrName -> RnM Name
rnHsTyVar _doc tyvar = lookupOccRn tyvar

findSplice :: [LHsDecl RdrName] -> RnM (HsGroup RdrName, Maybe (SpliceDecl RdrName, [LHsDecl RdrName]))
findSplice ds = addl emptyRdrGroup ds

addl :: HsGroup RdrName -> [LHsDecl RdrName]
     -> RnM (HsGroup RdrName, Maybe (SpliceDecl RdrName, [LHsDecl RdrName]))
-- This stuff reverses the declarations (again) but it doesn't matter
addl gp []           = return (gp, Nothing)
addl gp (L l d : ds) = add gp l d ds


add :: HsGroup RdrName -> SrcSpan -> HsDecl RdrName -> [LHsDecl RdrName]
    -> RnM (HsGroup RdrName, Maybe (SpliceDecl RdrName, [LHsDecl RdrName]))

add gp loc (SpliceD splice@(SpliceDecl _ flag)) ds
  = do { -- We've found a top-level splice.  If it is an *implicit* one
         -- (i.e. a naked top level expression)
         case flag of
           Explicit -> return ()
           Implicit -> do { th_on <- xoptM Opt_TemplateHaskell
                          ; unless th_on $ setSrcSpan loc $
                            failWith badImplicitSplice }

       ; return (gp, Just (splice, ds)) }
  where
    badImplicitSplice = ptext (sLit "Parse error: naked expression at top level")
                     $$ ptext (sLit "Perhaps you intended to use TemplateHaskell")

add gp _ (QuasiQuoteD qq) ds            -- Expand quasiquotes
  = do { ds' <- runQuasiQuoteDecl qq
       ; addl gp (ds' ++ ds) }

-- Class declarations: pull out the fixity signatures to the top
add gp@(HsGroup {hs_tyclds = ts, hs_fixds = fs}) l (TyClD d) ds
  | isClassDecl d
  = let fsigs = [ L l f | L l (FixSig f) <- tcdSigs d ] in
    addl (gp { hs_tyclds = add_tycld (L l d) ts, hs_fixds = fsigs ++ fs}) ds
  | otherwise
  = addl (gp { hs_tyclds = add_tycld (L l d) ts }) ds

-- Signatures: fixity sigs go a different place than all others
add gp@(HsGroup {hs_fixds = ts}) l (SigD (FixSig f)) ds
  = addl (gp {hs_fixds = L l f : ts}) ds
add gp@(HsGroup {hs_valds = ts}) l (SigD d) ds
  = addl (gp {hs_valds = add_sig (L l d) ts}) ds

-- Value declarations: use add_bind
add gp@(HsGroup {hs_valds  = ts}) l (ValD d) ds
  = addl (gp { hs_valds = add_bind (L l d) ts }) ds

-- Role annotations: added to the TyClGroup
add gp@(HsGroup {hs_tyclds = ts}) l (RoleAnnotD d) ds
  = addl (gp { hs_tyclds = add_role_annot (L l d) ts }) ds

-- The rest are routine
add gp@(HsGroup {hs_instds = ts})  l (InstD d) ds
  = addl (gp { hs_instds = L l d : ts }) ds
add gp@(HsGroup {hs_derivds = ts})  l (DerivD d) ds
  = addl (gp { hs_derivds = L l d : ts }) ds
add gp@(HsGroup {hs_defds  = ts})  l (DefD d) ds
  = addl (gp { hs_defds = L l d : ts }) ds
add gp@(HsGroup {hs_fords  = ts}) l (ForD d) ds
  = addl (gp { hs_fords = L l d : ts }) ds
add gp@(HsGroup {hs_warnds  = ts})  l (WarningD d) ds
  = addl (gp { hs_warnds = L l d : ts }) ds
add gp@(HsGroup {hs_annds  = ts}) l (AnnD d) ds
  = addl (gp { hs_annds = L l d : ts }) ds
add gp@(HsGroup {hs_ruleds  = ts}) l (RuleD d) ds
  = addl (gp { hs_ruleds = L l d : ts }) ds
add gp@(HsGroup {hs_vects  = ts}) l (VectD d) ds
  = addl (gp { hs_vects = L l d : ts }) ds
add gp l (DocD d) ds
  = addl (gp { hs_docs = (L l d) : (hs_docs gp) })  ds

add_tycld :: LTyClDecl a -> [TyClGroup a] -> [TyClGroup a]
add_tycld d []       = [TyClGroup { group_tyclds = [d], group_roles = [] }]
add_tycld d (ds@(TyClGroup { group_tyclds = tyclds }):dss)
  = ds { group_tyclds = d : tyclds } : dss

add_role_annot :: LRoleAnnotDecl a -> [TyClGroup a] -> [TyClGroup a]
add_role_annot d [] = [TyClGroup { group_tyclds = [], group_roles = [d] }]
add_role_annot d (tycls@(TyClGroup { group_roles = roles }) : rest)
  = tycls { group_roles = d : roles } : rest

add_bind :: LHsBind a -> HsValBinds a -> HsValBinds a
add_bind b (ValBindsIn bs sigs) = ValBindsIn (bs `snocBag` b) sigs
add_bind _ (ValBindsOut {})     = panic "RdrHsSyn:add_bind"

add_sig :: LSig a -> HsValBinds a -> HsValBinds a
add_sig s (ValBindsIn bs sigs) = ValBindsIn bs (s:sigs)
add_sig _ (ValBindsOut {})     = panic "RdrHsSyn:add_sig"