Issue #12844: More than 255 arguments can now be passed to a function.

4 files changed, 71 insertions, 68 deletions

diff --git a/Doc/whatsnew/3.7.rst b/Doc/whatsnew/3.7.rst
index 0f6ebc4..d306d40 100644
--- a/Doc/whatsnew/3.7.rst
+++ b/Doc/whatsnew/3.7.rst
@@ -75,6 +75,8 @@ New Features
 Other Language Changes
 ======================
 
+* More than 255 arguments can now be passed to a function.
+  (Contributed by Serhiy Storchaka in :issue:`12844`.)
 
 
 New Modules
diff --git a/Lib/test/test_syntax.py b/Lib/test/test_syntax.py
index 80e36fd..6364266 100644
--- a/Lib/test/test_syntax.py
+++ b/Lib/test/test_syntax.py
@@ -139,69 +139,73 @@ SyntaxError: Generator expression must be parenthesized if not sole argument
 >>> f((x for x in L), 1)
 [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
 
->>> f(i0,  i1,  i2,  i3,  i4,  i5,  i6,  i7,  i8,  i9,  i10,  i11,
-...   i12,  i13,  i14,  i15,  i16,  i17,  i18,  i19,  i20,  i21,  i22,
-...   i23,  i24,  i25,  i26,  i27,  i28,  i29,  i30,  i31,  i32,  i33,
-...   i34,  i35,  i36,  i37,  i38,  i39,  i40,  i41,  i42,  i43,  i44,
-...   i45,  i46,  i47,  i48,  i49,  i50,  i51,  i52,  i53,  i54,  i55,
-...   i56,  i57,  i58,  i59,  i60,  i61,  i62,  i63,  i64,  i65,  i66,
-...   i67,  i68,  i69,  i70,  i71,  i72,  i73,  i74,  i75,  i76,  i77,
-...   i78,  i79,  i80,  i81,  i82,  i83,  i84,  i85,  i86,  i87,  i88,
-...   i89,  i90,  i91,  i92,  i93,  i94,  i95,  i96,  i97,  i98,  i99,
-...   i100,  i101,  i102,  i103,  i104,  i105,  i106,  i107,  i108,
-...   i109,  i110,  i111,  i112,  i113,  i114,  i115,  i116,  i117,
-...   i118,  i119,  i120,  i121,  i122,  i123,  i124,  i125,  i126,
-...   i127,  i128,  i129,  i130,  i131,  i132,  i133,  i134,  i135,
-...   i136,  i137,  i138,  i139,  i140,  i141,  i142,  i143,  i144,
-...   i145,  i146,  i147,  i148,  i149,  i150,  i151,  i152,  i153,
-...   i154,  i155,  i156,  i157,  i158,  i159,  i160,  i161,  i162,
-...   i163,  i164,  i165,  i166,  i167,  i168,  i169,  i170,  i171,
-...   i172,  i173,  i174,  i175,  i176,  i177,  i178,  i179,  i180,
-...   i181,  i182,  i183,  i184,  i185,  i186,  i187,  i188,  i189,
-...   i190,  i191,  i192,  i193,  i194,  i195,  i196,  i197,  i198,
-...   i199,  i200,  i201,  i202,  i203,  i204,  i205,  i206,  i207,
-...   i208,  i209,  i210,  i211,  i212,  i213,  i214,  i215,  i216,
-...   i217,  i218,  i219,  i220,  i221,  i222,  i223,  i224,  i225,
-...   i226,  i227,  i228,  i229,  i230,  i231,  i232,  i233,  i234,
-...   i235,  i236,  i237,  i238,  i239,  i240,  i241,  i242,  i243,
-...   i244,  i245,  i246,  i247,  i248,  i249,  i250,  i251,  i252,
-...   i253,  i254,  i255)
-Traceback (most recent call last):
-SyntaxError: more than 255 arguments
-
-The actual error cases counts positional arguments, keyword arguments,
-and generator expression arguments separately.  This test combines the
-three.
-
->>> f(i0,  i1,  i2,  i3,  i4,  i5,  i6,  i7,  i8,  i9,  i10,  i11,
-...   i12,  i13,  i14,  i15,  i16,  i17,  i18,  i19,  i20,  i21,  i22,
-...   i23,  i24,  i25,  i26,  i27,  i28,  i29,  i30,  i31,  i32,  i33,
-...   i34,  i35,  i36,  i37,  i38,  i39,  i40,  i41,  i42,  i43,  i44,
-...   i45,  i46,  i47,  i48,  i49,  i50,  i51,  i52,  i53,  i54,  i55,
-...   i56,  i57,  i58,  i59,  i60,  i61,  i62,  i63,  i64,  i65,  i66,
-...   i67,  i68,  i69,  i70,  i71,  i72,  i73,  i74,  i75,  i76,  i77,
-...   i78,  i79,  i80,  i81,  i82,  i83,  i84,  i85,  i86,  i87,  i88,
-...   i89,  i90,  i91,  i92,  i93,  i94,  i95,  i96,  i97,  i98,  i99,
-...   i100,  i101,  i102,  i103,  i104,  i105,  i106,  i107,  i108,
-...   i109,  i110,  i111,  i112,  i113,  i114,  i115,  i116,  i117,
-...   i118,  i119,  i120,  i121,  i122,  i123,  i124,  i125,  i126,
-...   i127,  i128,  i129,  i130,  i131,  i132,  i133,  i134,  i135,
-...   i136,  i137,  i138,  i139,  i140,  i141,  i142,  i143,  i144,
-...   i145,  i146,  i147,  i148,  i149,  i150,  i151,  i152,  i153,
-...   i154,  i155,  i156,  i157,  i158,  i159,  i160,  i161,  i162,
-...   i163,  i164,  i165,  i166,  i167,  i168,  i169,  i170,  i171,
-...   i172,  i173,  i174,  i175,  i176,  i177,  i178,  i179,  i180,
-...   i181,  i182,  i183,  i184,  i185,  i186,  i187,  i188,  i189,
-...   i190,  i191,  i192,  i193,  i194,  i195,  i196,  i197,  i198,
-...   i199,  i200,  i201,  i202,  i203,  i204,  i205,  i206,  i207,
-...   i208,  i209,  i210,  i211,  i212,  i213,  i214,  i215,  i216,
-...   i217,  i218,  i219,  i220,  i221,  i222,  i223,  i224,  i225,
-...   i226,  i227,  i228,  i229,  i230,  i231,  i232,  i233,  i234,
-...   i235, i236,  i237,  i238,  i239,  i240,  i241,  i242,  i243,
-...   (x for x in i244),  i245,  i246,  i247,  i248,  i249,  i250,  i251,
-...    i252=1, i253=1,  i254=1,  i255=1)
-Traceback (most recent call last):
-SyntaxError: more than 255 arguments
+>>> def g(*args, **kwargs):
+...     print(args, sorted(kwargs.items()))
+>>> g(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
+...   20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,
+...   38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55,
+...   56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73,
+...   74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91,
+...   92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107,
+...   108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121,
+...   122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135,
+...   136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149,
+...   150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163,
+...   164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177,
+...   178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191,
+...   192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205,
+...   206, 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219,
+...   220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233,
+...   234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247,
+...   248, 249, 250, 251, 252, 253, 254, 255, 256, 257, 258, 259, 260, 261,
+...   262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275,
+...   276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, 289,
+...   290, 291, 292, 293, 294, 295, 296, 297, 298, 299)  # doctest: +ELLIPSIS
+(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, ..., 297, 298, 299) []
+
+>>> g(a000=0, a001=1, a002=2, a003=3, a004=4, a005=5, a006=6, a007=7, a008=8,
+...   a009=9, a010=10, a011=11, a012=12, a013=13, a014=14, a015=15, a016=16,
+...   a017=17, a018=18, a019=19, a020=20, a021=21, a022=22, a023=23, a024=24,
+...   a025=25, a026=26, a027=27, a028=28, a029=29, a030=30, a031=31, a032=32,
+...   a033=33, a034=34, a035=35, a036=36, a037=37, a038=38, a039=39, a040=40,
+...   a041=41, a042=42, a043=43, a044=44, a045=45, a046=46, a047=47, a048=48,
+...   a049=49, a050=50, a051=51, a052=52, a053=53, a054=54, a055=55, a056=56,
+...   a057=57, a058=58, a059=59, a060=60, a061=61, a062=62, a063=63, a064=64,
+...   a065=65, a066=66, a067=67, a068=68, a069=69, a070=70, a071=71, a072=72,
+...   a073=73, a074=74, a075=75, a076=76, a077=77, a078=78, a079=79, a080=80,
+...   a081=81, a082=82, a083=83, a084=84, a085=85, a086=86, a087=87, a088=88,
+...   a089=89, a090=90, a091=91, a092=92, a093=93, a094=94, a095=95, a096=96,
+...   a097=97, a098=98, a099=99, a100=100, a101=101, a102=102, a103=103,
+...   a104=104, a105=105, a106=106, a107=107, a108=108, a109=109, a110=110,
+...   a111=111, a112=112, a113=113, a114=114, a115=115, a116=116, a117=117,
+...   a118=118, a119=119, a120=120, a121=121, a122=122, a123=123, a124=124,
+...   a125=125, a126=126, a127=127, a128=128, a129=129, a130=130, a131=131,
+...   a132=132, a133=133, a134=134, a135=135, a136=136, a137=137, a138=138,
+...   a139=139, a140=140, a141=141, a142=142, a143=143, a144=144, a145=145,
+...   a146=146, a147=147, a148=148, a149=149, a150=150, a151=151, a152=152,
+...   a153=153, a154=154, a155=155, a156=156, a157=157, a158=158, a159=159,
+...   a160=160, a161=161, a162=162, a163=163, a164=164, a165=165, a166=166,
+...   a167=167, a168=168, a169=169, a170=170, a171=171, a172=172, a173=173,
+...   a174=174, a175=175, a176=176, a177=177, a178=178, a179=179, a180=180,
+...   a181=181, a182=182, a183=183, a184=184, a185=185, a186=186, a187=187,
+...   a188=188, a189=189, a190=190, a191=191, a192=192, a193=193, a194=194,
+...   a195=195, a196=196, a197=197, a198=198, a199=199, a200=200, a201=201,
+...   a202=202, a203=203, a204=204, a205=205, a206=206, a207=207, a208=208,
+...   a209=209, a210=210, a211=211, a212=212, a213=213, a214=214, a215=215,
+...   a216=216, a217=217, a218=218, a219=219, a220=220, a221=221, a222=222,
+...   a223=223, a224=224, a225=225, a226=226, a227=227, a228=228, a229=229,
+...   a230=230, a231=231, a232=232, a233=233, a234=234, a235=235, a236=236,
+...   a237=237, a238=238, a239=239, a240=240, a241=241, a242=242, a243=243,
+...   a244=244, a245=245, a246=246, a247=247, a248=248, a249=249, a250=250,
+...   a251=251, a252=252, a253=253, a254=254, a255=255, a256=256, a257=257,
+...   a258=258, a259=259, a260=260, a261=261, a262=262, a263=263, a264=264,
+...   a265=265, a266=266, a267=267, a268=268, a269=269, a270=270, a271=271,
+...   a272=272, a273=273, a274=274, a275=275, a276=276, a277=277, a278=278,
+...   a279=279, a280=280, a281=281, a282=282, a283=283, a284=284, a285=285,
+...   a286=286, a287=287, a288=288, a289=289, a290=290, a291=291, a292=292,
+...   a293=293, a294=294, a295=295, a296=296, a297=297, a298=298, a299=299)
+...  # doctest: +ELLIPSIS
+() [('a000', 0), ('a001', 1), ('a002', 2), ..., ('a298', 298), ('a299', 299)]
 
 >>> f(lambda x: x[0] = 3)
 Traceback (most recent call last):
diff --git a/Misc/NEWS b/Misc/NEWS
index c18d787..56f2aed 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,8 @@ What's New in Python 3.7.0 alpha 1
 Core and Builtins
 -----------------
 
+- Issue #12844: More than 255 arguments can now be passed to a function.
+
 - Issue #28782: Fix a bug in the implementation ``yield from`` when checking
   if the next instruction is YIELD_FROM. Regression introduced by WORDCODE
   (issue #26647).
diff --git a/Python/ast.c b/Python/ast.c
index 82f4529..e6786d4 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -2738,11 +2738,6 @@ ast_for_call(struct compiling *c, const node *n, expr_ty func)
         return NULL;
     }
 
-    if (nargs + nkeywords + ngens > 255) {
-        ast_error(c, n, "more than 255 arguments");
-        return NULL;
-    }
-
     args = _Py_asdl_seq_new(nargs + ngens, c->c_arena);
     if (!args)
         return NULL;