-- Equality
cheapEqExpr, tcEqExpr, tcEqExprX, applyTypeToArgs, applyTypeToArg,
- dataConInstPat
+ dataConInstPat, dataConOccInstPat
) where
#include "HsVersions.h"
import PprCore ( pprCoreExpr )
import Var ( Var, TyVar, CoVar, isCoVar, tyVarKind, setVarUnique,
mkCoVar, mkTyVar, mkCoVar )
+import OccName ( OccName, occNameFS, mkVarOcc )
import VarSet ( unionVarSet )
import VarEnv
import Name ( hashName, mkSysTvName )
import DynFlags ( DynFlags, DynFlag(Opt_DictsCheap), dopt )
import TysPrim ( alphaTy ) -- Debugging only
import Util ( equalLength, lengthAtLeast, foldl2 )
+import FastString ( mkFastString )
\end{code}
coArgs = decomposeCo (length tyVars) co
-- This goes here to avoid circularity between DataCon and Id
-dataConInstPat :: [Unique] -- An infinite list of uniques
+dataConInstPat :: [Unique] -- A long enough list of uniques, at least one for each binder
-> DataCon
-> [Type] -- Types to instantiate the universally quantified tyvars
-> ([TyVar], [CoVar], [Id]) -- Return instantiated variables
+-- dataConInstPat us con inst_tys returns a triple (ex_tvs, co_tvs, arg_ids),
+--
+-- ex_tvs are intended to be used as binders for existential type args
+--
+-- co_tvs are intended to be used as binders for coercion args and the kinds
+-- of these vars have been instantiated by the inst_tys and the ex_tys
+--
+-- arg_ids are indended to be used as binders for value arguments, including
+-- dicts, and have their types instantiated with inst_tys and ex_tys
+--
+-- Example.
+-- The following constructor T1
+--
+-- data T a where
+-- T1 :: forall b. Int -> b -> T(a,b)
+-- ...
+--
+-- has representation type
+-- forall a. forall a1. forall a2. forall b. (a :=: (a1,a2)) =>
+-- Int -> b -> T a
+--
+-- dataConInstPat us T1 (a1',a2') will return
+--
+-- ([a1'', a2'', b''],[c :: (a1',a2'):=:(a1'',a2'')],[x :: Int,y :: b''])
+--
+-- where the double-primed variables are created from the unique list input
dataConInstPat uniqs con inst_tys
+ = dataConOccInstPat uniqs occs con inst_tys
+ where
+ -- dataConOccInstPat doesn't actually make use of the OccName directly for
+ -- existential and coercion variable binders, so it is right to just
+ -- use the VarName namespace for all of the OccNames
+ occs = mk_occs 1
+ mk_occs n = mkVarOcc ("ipv" ++ show n) : mk_occs (n+1)
+
+dataConOccInstPat :: [Unique] -- A long enough list of uniques, at least one for each binder
+ -> [OccName] -- An equally long list of OccNames to use
+ -> DataCon
+ -> [Type] -- Types to instantiate the universally quantified tyvars
+ -> ([TyVar], [CoVar], [Id]) -- Return instantiated variables
+-- This function actually does the job specified in the comment for
+-- dataConInstPat, but uses the specified list of OccNames. This is
+-- is necessary for use in e.g. tcIfaceDataAlt
+dataConOccInstPat uniqs occs con inst_tys
= (ex_bndrs, co_bndrs, id_bndrs)
where
univ_tvs = dataConUnivTyVars con
n_co = length eq_spec
n_id = length arg_tys
- -- split the uniques
- (ex_uniqs, uniqs') = splitAt n_ex uniqs
+ -- split the Uniques and OccNames
+ (ex_uniqs, uniqs') = splitAt n_ex uniqs
(co_uniqs, id_uniqs) = splitAt n_co uniqs'
+ (ex_occs, occs') = splitAt n_ex occs
+ (co_occs, id_occs) = splitAt n_co occs'
+
-- make existential type variables
- mk_ex_var uniq var = setVarUnique var uniq
- ex_bndrs = zipWith mk_ex_var ex_uniqs ex_tvs
+ mk_ex_var uniq occ var = mkTyVar new_name kind
+ where
+ new_name = mkSysTvName uniq (occNameFS occ)
+ kind = tyVarKind var
+
+ ex_bndrs = zipWith3 mk_ex_var ex_uniqs ex_occs ex_tvs
-- make the instantiation substitution
inst_subst = substTyWith (univ_tvs ++ ex_tvs) (inst_tys ++ map mkTyVarTy ex_bndrs)
- -- make a new coercion vars, instantiating kind
- mk_co_var uniq eq_pred = mkCoVar new_name (inst_subst (mkPredTy eq_pred))
+ -- make new coercion vars, instantiating kind
+ mk_co_var uniq occ eq_pred = mkCoVar new_name (inst_subst (mkPredTy eq_pred))
where
- new_name = mkSysTvName uniq FSLIT("co")
+ new_name = mkSysTvName uniq (occNameFS occ)
- co_bndrs = zipWith mk_co_var co_uniqs eq_preds
+ co_bndrs = zipWith3 mk_co_var co_uniqs co_occs eq_preds
-- make value vars, instantiating types
- mk_id_var uniq ty = mkSysLocal FSLIT("ca") uniq (inst_subst ty)
-
- id_bndrs = zipWith mk_id_var id_uniqs arg_tys
-
+ mk_id_var uniq occ ty = mkUserLocal occ uniq (inst_subst ty) noSrcLoc
+ id_bndrs = zipWith3 mk_id_var id_uniqs id_occs arg_tys
exprIsConApp_maybe :: CoreExpr -> Maybe (DataCon, [CoreExpr])
-- Returns (Just (dc, [x1..xn])) if the argument expression is
eta_expand n us expr ty
= ASSERT2 (exprType expr `coreEqType` ty, ppr (exprType expr) $$ ppr ty)
case splitForAllTy_maybe ty of {
- Just (tv,ty') -> Lam tv (eta_expand n us (App expr (Type (mkTyVarTy tv))) ty')
+ Just (tv,ty') ->
+
+ Lam lam_tv (eta_expand n us2 (App expr (Type (mkTyVarTy lam_tv))) (substTyWith [tv] [mkTyVarTy lam_tv] ty'))
+ where
+ lam_tv = mkTyVar (mkSysTvName uniq FSLIT("etaT")) (tyVarKind tv)
+ (uniq:us2) = us
; Nothing ->