Repository : http://darcs.haskell.org/ghc.git/
On branch : master https://github.com/ghc/ghc/commit/cf7e2fa4c37c078f5bb2bad29cdd78b64c6792b8 >--------------------------------------------------------------- commit cf7e2fa4c37c078f5bb2bad29cdd78b64c6792b8 Author: Simon Peyton Jones <[email protected]> Date: Mon May 27 15:36:08 2013 +0100 Accept derived Read on an empty data type (Trac #7931) >--------------------------------------------------------------- compiler/typecheck/TcGenDeriv.lhs | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/compiler/typecheck/TcGenDeriv.lhs b/compiler/typecheck/TcGenDeriv.lhs index 5726031..b8c7c8c 100644 --- a/compiler/typecheck/TcGenDeriv.lhs +++ b/compiler/typecheck/TcGenDeriv.lhs @@ -902,7 +902,8 @@ gen_Read_binds get_fixity loc tycon read_prec = mkHsVarBind loc readPrec_RDR (nlHsApp (nlHsVar parens_RDR) read_cons) - read_cons = foldr1 mk_alt (read_nullary_cons ++ read_non_nullary_cons) + read_cons | null data_cons = error_Expr "Derived Read on empty data type" -- Trac #7931 + | otherwise = foldr1 mk_alt (read_nullary_cons ++ read_non_nullary_cons) read_non_nullary_cons = map read_non_nullary_con non_nullary_cons read_nullary_cons _______________________________________________ ghc-commits mailing list [email protected] http://www.haskell.org/mailman/listinfo/ghc-commits
