cpython/Lib/test/test_grammar.py

# Python test set -- part 1, grammar.
# This just tests whether the parser accepts them all.

from test.support import check_syntax_error
from test.support import import_helper
import inspect
import unittest
import sys
import warnings
# testing import *
from sys import *

# different import patterns to check that __annotations__ does not interfere
# with import machinery
import test.typinganndata.ann_module as ann_module
import typing
from test.typinganndata import ann_module2
import test

# These are shared with test_tokenize and other test modules.
#
# Note: since several test cases filter out floats by looking for "e" and ".",
# don't add hexadecimal literals that contain "e" or "E".
VALID_UNDERSCORE_LITERALS = [
    '0_0_0',
    '4_2',
    '1_0000_0000',
    '0b1001_0100',
    '0xffff_ffff',
    '0o5_7_7',
    '1_00_00.5',
    '1_00_00.5e5',
    '1_00_00e5_1',
    '1e1_0',
    '.1_4',
    '.1_4e1',
    '0b_0',
    '0x_f',
    '0o_5',
    '1_00_00j',
    '1_00_00.5j',
    '1_00_00e5_1j',
    '.1_4j',
    '(1_2.5+3_3j)',
    '(.5_6j)',
]
INVALID_UNDERSCORE_LITERALS = [
    # Trailing underscores:
    '0_',
    '42_',
    '1.4j_',
    '0x_',
    '0b1_',
    '0xf_',
    '0o5_',
    '0 if 1_Else 1',
    # Underscores in the base selector:
    '0_b0',
    '0_xf',
    '0_o5',
    # Old-style octal, still disallowed:
    '0_7',
    '09_99',
    # Multiple consecutive underscores:
    '4_______2',
    '0.1__4',
    '0.1__4j',
    '0b1001__0100',
    '0xffff__ffff',
    '0x___',
    '0o5__77',
    '1e1__0',
    '1e1__0j',
    # Underscore right before a dot:
    '1_.4',
    '1_.4j',
    # Underscore right after a dot:
    '1._4',
    '1._4j',
    '._5',
    '._5j',
    # Underscore right after a sign:
    '1.0e+_1',
    '1.0e+_1j',
    # Underscore right before j:
    '1.4_j',
    '1.4e5_j',
    # Underscore right before e:
    '1_e1',
    '1.4_e1',
    '1.4_e1j',
    # Underscore right after e:
    '1e_1',
    '1.4e_1',
    '1.4e_1j',
    # Complex cases with parens:
    '(1+1.5_j_)',
    '(1+1.5_j)',
]


class TokenTests(unittest.TestCase):

    from test.support import check_syntax_error
    from test.support.warnings_helper import check_syntax_warning

    def test_backslash(self):
        # Backslash means line continuation:
        x = 1 \
        + 1
        self.assertEqual(x, 2, 'backslash for line continuation')

        # Backslash does not means continuation in comments :\
        x = 0
        self.assertEqual(x, 0, 'backslash ending comment')

    def test_plain_integers(self):
        self.assertEqual(type(000), type(0))
        self.assertEqual(0xff, 255)
        self.assertEqual(0o377, 255)
        self.assertEqual(2147483647, 0o17777777777)
        self.assertEqual(0b1001, 9)
        # "0x" is not a valid literal
        self.assertRaises(SyntaxError, eval, "0x")
        from sys import maxsize
        if maxsize == 2147483647:
            self.assertEqual(-2147483647-1, -0o20000000000)
            # XXX -2147483648
            self.assertTrue(0o37777777777 > 0)
            self.assertTrue(0xffffffff > 0)
            self.assertTrue(0b1111111111111111111111111111111 > 0)
            for s in ('2147483648', '0o40000000000', '0x100000000',
                      '0b10000000000000000000000000000000'):
                try:
                    x = eval(s)
                except OverflowError:
                    self.fail("OverflowError on huge integer literal %r" % s)
        elif maxsize == 9223372036854775807:
            self.assertEqual(-9223372036854775807-1, -0o1000000000000000000000)
            self.assertTrue(0o1777777777777777777777 > 0)
            self.assertTrue(0xffffffffffffffff > 0)
            self.assertTrue(0b11111111111111111111111111111111111111111111111111111111111111 > 0)
            for s in '9223372036854775808', '0o2000000000000000000000', \
                     '0x10000000000000000', \
                     '0b100000000000000000000000000000000000000000000000000000000000000':
                try:
                    x = eval(s)
                except OverflowError:
                    self.fail("OverflowError on huge integer literal %r" % s)
        else:
            self.fail('Weird maxsize value %r' % maxsize)

    def test_long_integers(self):
        x = 0
        x = 0xffffffffffffffff
        x = 0Xffffffffffffffff
        x = 0o77777777777777777
        x = 0O77777777777777777
        x = 123456789012345678901234567890
        x = 0b100000000000000000000000000000000000000000000000000000000000000000000
        x = 0B111111111111111111111111111111111111111111111111111111111111111111111

    def test_floats(self):
        x = 3.14
        x = 314.
        x = 0.314
        x = 000.314
        x = .314
        x = 3e14
        x = 3E14
        x = 3e-14
        x = 3e+14
        x = 3.e14
        x = .3e14
        x = 3.1e4

    def test_float_exponent_tokenization(self):
        # See issue 21642.
        with warnings.catch_warnings():
            warnings.simplefilter('ignore', SyntaxWarning)
            self.assertEqual(eval("1 if 1else 0"), 1)
            self.assertEqual(eval("1 if 0else 0"), 0)
        self.assertRaises(SyntaxError, eval, "0 if 1Else 0")

    def test_underscore_literals(self):
        for lit in VALID_UNDERSCORE_LITERALS:
            self.assertEqual(eval(lit), eval(lit.replace('_', '')))
        for lit in INVALID_UNDERSCORE_LITERALS:
            self.assertRaises(SyntaxError, eval, lit)
        # Sanity check: no literal begins with an underscore
        self.assertRaises(NameError, eval, "_0")

    def test_bad_numerical_literals(self):
        check = self.check_syntax_error
        check("0b12", "invalid digit '2' in binary literal")
        check("0b1_2", "invalid digit '2' in binary literal")
        check("0b2", "invalid digit '2' in binary literal")
        check("0b1_", "invalid binary literal")
        check("0b", "invalid binary literal")
        check("0o18", "invalid digit '8' in octal literal")
        check("0o1_8", "invalid digit '8' in octal literal")
        check("0o8", "invalid digit '8' in octal literal")
        check("0o1_", "invalid octal literal")
        check("0o", "invalid octal literal")
        check("0x1_", "invalid hexadecimal literal")
        check("0x", "invalid hexadecimal literal")
        check("1_", "invalid decimal literal")
        check("012",
              "leading zeros in decimal integer literals are not permitted; "
              "use an 0o prefix for octal integers")
        check("1.2_", "invalid decimal literal")
        check("1e2_", "invalid decimal literal")
        check("1e+", "invalid decimal literal")

    def test_end_of_numerical_literals(self):
        def check(test, error=False):
            with self.subTest(expr=test):
                if error:
                    with warnings.catch_warnings(record=True) as w:
                        with self.assertRaisesRegex(SyntaxError,
                                    r'invalid \w+ literal'):
                            compile(test, "<testcase>", "eval")
                    self.assertEqual(w,  [])
                else:
                    self.check_syntax_warning(test,
                            errtext=r'invalid \w+ literal')

        for num in "0xf", "0o7", "0b1", "9", "0", "1.", "1e3", "1j":
            compile(num, "<testcase>", "eval")
            check(f"{num}and x", error=(num == "0xf"))
            check(f"{num}or x", error=(num == "0"))
            check(f"{num}in x")
            check(f"{num}not in x")
            check(f"{num}if x else y")
            check(f"x if {num}else y", error=(num == "0xf"))
            check(f"[{num}for x in ()]")
            check(f"{num}spam", error=True)

            # gh-88943: Invalid non-ASCII character following a numerical literal.
            with self.assertRaisesRegex(SyntaxError, r"invalid character '⁄' \(U\+2044\)"):
                compile(f"{num}⁄7", "<testcase>", "eval")

            with self.assertWarnsRegex(SyntaxWarning, r'invalid \w+ literal'):
                compile(f"{num}is x", "<testcase>", "eval")
            with warnings.catch_warnings():
                warnings.simplefilter('error', SyntaxWarning)
                with self.assertRaisesRegex(SyntaxError,
                            r'invalid \w+ literal'):
                    compile(f"{num}is x", "<testcase>", "eval")

        check("[0x1ffor x in ()]")
        check("[0x1for x in ()]")
        check("[0xfor x in ()]")

    def test_string_literals(self):
        x = ''; y = ""; self.assertTrue(len(x) == 0 and x == y)
        x = '\''; y = "'"; self.assertTrue(len(x) == 1 and x == y and ord(x) == 39)
        x = '"'; y = "\""; self.assertTrue(len(x) == 1 and x == y and ord(x) == 34)
        x = "doesn't \"shrink\" does it"
        y = 'doesn\'t "shrink" does it'
        self.assertTrue(len(x) == 24 and x == y)
        x = "does \"shrink\" doesn't it"
        y = 'does "shrink" doesn\'t it'
        self.assertTrue(len(x) == 24 and x == y)
        x = """
The "quick"
brown fox
jumps over
the 'lazy' dog.
"""
        y = '\nThe "quick"\nbrown fox\njumps over\nthe \'lazy\' dog.\n'
        self.assertEqual(x, y)
        y = '''
The "quick"
brown fox
jumps over
the 'lazy' dog.
'''
        self.assertEqual(x, y)
        y = "\n\
The \"quick\"\n\
brown fox\n\
jumps over\n\
the 'lazy' dog.\n\
"
        self.assertEqual(x, y)
        y = '\n\
The \"quick\"\n\
brown fox\n\
jumps over\n\
the \'lazy\' dog.\n\
'
        self.assertEqual(x, y)

    def test_ellipsis(self):
        x = ...
        self.assertTrue(x is Ellipsis)
        self.assertRaises(SyntaxError, eval, ".. .")

    def test_eof_error(self):
        samples = ("def foo(", "\ndef foo(", "def foo(\n")
        for s in samples:
            with self.assertRaises(SyntaxError) as cm:
                compile(s, "<test>", "exec")
            self.assertIn("was never closed", str(cm.exception))

var_annot_global: int # a global annotated is necessary for test_var_annot


class GrammarTests(unittest.TestCase):

    from test.support import check_syntax_error
    from test.support.warnings_helper import check_syntax_warning
    from test.support.warnings_helper import check_no_warnings

    # single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
    # XXX can't test in a script -- this rule is only used when interactive

    # file_input: (NEWLINE | stmt)* ENDMARKER
    # Being tested as this very moment this very module

    # expr_input: testlist NEWLINE
    # XXX Hard to test -- used only in calls to input()

    def test_eval_input(self):
        # testlist ENDMARKER
        x = eval('1, 0 or 1')

    def test_var_annot_basics(self):
        # all these should be allowed
        var1: int = 5
        var2: [int, str]
        my_lst = [42]
        def one():
            return 1
        int.new_attr: int
        [list][0]: type
        my_lst[one()-1]: int = 5
        self.assertEqual(my_lst, [5])

    def test_var_annot_syntax_errors(self):
        # parser pass
        check_syntax_error(self, "def f: int")
        check_syntax_error(self, "x: int: str")
        check_syntax_error(self, "def f():\n"
                                 "    nonlocal x: int\n")
        check_syntax_error(self, "def f():\n"
                                 "    global x: int\n")
        check_syntax_error(self, "x: int = y = 1")
        check_syntax_error(self, "z = w: int = 1")
        check_syntax_error(self, "x: int = y: int = 1")
        # AST pass
        check_syntax_error(self, "[x, 0]: int\n")
        check_syntax_error(self, "f(): int\n")
        check_syntax_error(self, "(x,): int")
        check_syntax_error(self, "def f():\n"
                                 "    (x, y): int = (1, 2)\n")
        # symtable pass
        check_syntax_error(self, "def f():\n"
                                 "    x: int\n"
                                 "    global x\n")
        check_syntax_error(self, "def f():\n"
                                 "    global x\n"
                                 "    x: int\n")
        check_syntax_error(self, "def f():\n"
                                 "    x: int\n"
                                 "    nonlocal x\n")
        check_syntax_error(self, "def f():\n"
                                 "    nonlocal x\n"
                                 "    x: int\n")

    def test_var_annot_basic_semantics(self):
        # execution order
        with self.assertRaises(ZeroDivisionError):
            no_name[does_not_exist]: no_name_again = 1/0
        with self.assertRaises(NameError):
            no_name[does_not_exist]: 1/0 = 0
        global var_annot_global

        # function semantics
        def f():
            st: str = "Hello"
            a.b: int = (1, 2)
            return st
        self.assertEqual(f.__annotations__, {})
        def f_OK():
            x: 1/0
        f_OK()
        def fbad():
            x: int
            print(x)
        with self.assertRaises(UnboundLocalError):
            fbad()
        def f2bad():
            (no_such_global): int
            print(no_such_global)
        try:
            f2bad()
        except Exception as e:
            self.assertIs(type(e), NameError)

        # class semantics
        class C:
            __foo: int
            s: str = "attr"
            z = 2
            def __init__(self, x):
                self.x: int = x
        self.assertEqual(C.__annotations__, {'_C__foo': int, 's': str})
        with self.assertRaises(NameError):
            class CBad:
                no_such_name_defined.attr: int = 0
        with self.assertRaises(NameError):
            class Cbad2(C):
                x: int
                x.y: list = []

    def test_annotations_inheritance(self):
        # Check that annotations are not inherited by derived classes
        class A:
            attr: int
        class B(A):
            pass
        class C(A):
            attr: str
        class D:
            attr2: int
        class E(A, D):
            pass
        class F(C, A):
            pass
        self.assertEqual(A.__annotations__, {"attr": int})
        self.assertEqual(B.__annotations__, {})
        self.assertEqual(C.__annotations__, {"attr" : str})
        self.assertEqual(D.__annotations__, {"attr2" : int})
        self.assertEqual(E.__annotations__, {})
        self.assertEqual(F.__annotations__, {})

    def test_var_annot_module_semantics(self):
        self.assertEqual(test.__annotations__, {})
        self.assertEqual(ann_module.__annotations__,
                         {'x': int, 'y': str, 'f': typing.Tuple[int, int], 'u': int | float})
        self.assertEqual(ann_module.M.__annotations__,
                         {'o': type})
        self.assertEqual(ann_module2.__annotations__, {})

    def test_var_annot_in_module(self):
        # check that functions fail the same way when executed
        # outside of module where they were defined
        ann_module3 = import_helper.import_fresh_module("test.typinganndata.ann_module3")
        with self.assertRaises(NameError):
            ann_module3.f_bad_ann()
        with self.assertRaises(NameError):
            ann_module3.g_bad_ann()
        with self.assertRaises(NameError):
            ann_module3.D_bad_ann(5)

    def test_var_annot_simple_exec(self):
        gns = {}; lns = {}
        exec("'docstring'\n"
             "x: int = 5\n", gns, lns)
        self.assertEqual(lns["__annotate__"](1), {'x': int})
        with self.assertRaises(KeyError):
            gns['__annotate__']

    def test_var_annot_rhs(self):
        ns = {}
        exec('x: tuple = 1, 2', ns)
        self.assertEqual(ns['x'], (1, 2))
        stmt = ('def f():\n'
                '    x: int = yield')
        exec(stmt, ns)
        self.assertEqual(list(ns['f']()), [None])

        ns = {"a": 1, 'b': (2, 3, 4), "c":5, "Tuple": typing.Tuple}
        exec('x: Tuple[int, ...] = a,*b,c', ns)
        self.assertEqual(ns['x'], (1, 2, 3, 4, 5))

    def test_funcdef(self):
        ### [decorators] 'def' NAME parameters ['->' test] ':' suite
        ### decorator: '@' namedexpr_test NEWLINE
        ### decorators: decorator+
        ### parameters: '(' [typedargslist] ')'
        ### typedargslist: ((tfpdef ['=' test] ',')*
        ###                ('*' [tfpdef] (',' tfpdef ['=' test])* [',' '**' tfpdef] | '**' tfpdef)
        ###                | tfpdef ['=' test] (',' tfpdef ['=' test])* [','])
        ### tfpdef: NAME [':' test]
        ### varargslist: ((vfpdef ['=' test] ',')*
        ###              ('*' [vfpdef] (',' vfpdef ['=' test])*  [',' '**' vfpdef] | '**' vfpdef)
        ###              | vfpdef ['=' test] (',' vfpdef ['=' test])* [','])
        ### vfpdef: NAME
        def f1(): pass
        f1()
        f1(*())
        f1(*(), **{})
        def f2(one_argument): pass
        def f3(two, arguments): pass
        self.assertEqual(f2.__code__.co_varnames, ('one_argument',))
        self.assertEqual(f3.__code__.co_varnames, ('two', 'arguments'))
        def a1(one_arg,): pass
        def a2(two, args,): pass
        def v0(*rest): pass
        def v1(a, *rest): pass
        def v2(a, b, *rest): pass

        f1()
        f2(1)
        f2(1,)
        f3(1, 2)
        f3(1, 2,)
        v0()
        v0(1)
        v0(1,)
        v0(1,2)
        v0(1,2,3,4,5,6,7,8,9,0)
        v1(1)
        v1(1,)
        v1(1,2)
        v1(1,2,3)
        v1(1,2,3,4,5,6,7,8,9,0)
        v2(1,2)
        v2(1,2,3)
        v2(1,2,3,4)
        v2(1,2,3,4,5,6,7,8,9,0)

        def d01(a=1): pass
        d01()
        d01(1)
        d01(*(1,))
        d01(*[] or [2])
        d01(*() or (), *{} and (), **() or {})
        d01(**{'a':2})
        d01(**{'a':2} or {})
        def d11(a, b=1): pass
        d11(1)
        d11(1, 2)
        d11(1, **{'b':2})
        def d21(a, b, c=1): pass
        d21(1, 2)
        d21(1, 2, 3)
        d21(*(1, 2, 3))
        d21(1, *(2, 3))
        d21(1, 2, *(3,))
        d21(1, 2, **{'c':3})
        def d02(a=1, b=2): pass
        d02()
        d02(1)
        d02(1, 2)
        d02(*(1, 2))
        d02(1, *(2,))
        d02(1, **{'b':2})
        d02(**{'a': 1, 'b': 2})
        def d12(a, b=1, c=2): pass
        d12(1)
        d12(1, 2)
        d12(1, 2, 3)
        def d22(a, b, c=1, d=2): pass
        d22(1, 2)
        d22(1, 2, 3)
        d22(1, 2, 3, 4)
        def d01v(a=1, *rest): pass
        d01v()
        d01v(1)
        d01v(1, 2)
        d01v(*(1, 2, 3, 4))
        d01v(*(1,))
        d01v(**{'a':2})
        def d11v(a, b=1, *rest): pass
        d11v(1)
        d11v(1, 2)
        d11v(1, 2, 3)
        def d21v(a, b, c=1, *rest): pass
        d21v(1, 2)
        d21v(1, 2, 3)
        d21v(1, 2, 3, 4)
        d21v(*(1, 2, 3, 4))
        d21v(1, 2, **{'c': 3})
        def d02v(a=1, b=2, *rest): pass
        d02v()
        d02v(1)
        d02v(1, 2)
        d02v(1, 2, 3)
        d02v(1, *(2, 3, 4))
        d02v(**{'a': 1, 'b': 2})
        def d12v(a, b=1, c=2, *rest): pass
        d12v(1)
        d12v(1, 2)
        d12v(1, 2, 3)
        d12v(1, 2, 3, 4)
        d12v(*(1, 2, 3, 4))
        d12v(1, 2, *(3, 4, 5))
        d12v(1, *(2,), **{'c': 3})
        def d22v(a, b, c=1, d=2, *rest): pass
        d22v(1, 2)
        d22v(1, 2, 3)
        d22v(1, 2, 3, 4)
        d22v(1, 2, 3, 4, 5)
        d22v(*(1, 2, 3, 4))
        d22v(1, 2, *(3, 4, 5))
        d22v(1, *(2, 3), **{'d': 4})

        # keyword argument type tests
        with warnings.catch_warnings():
            warnings.simplefilter('ignore', BytesWarning)
            try:
                str('x', **{b'foo':1 })
            except TypeError:
                pass
            else:
                self.fail('Bytes should not work as keyword argument names')
        # keyword only argument tests
        def pos0key1(*, key): return key
        pos0key1(key=100)
        def pos2key2(p1, p2, *, k1, k2=100): return p1,p2,k1,k2
        pos2key2(1, 2, k1=100)
        pos2key2(1, 2, k1=100, k2=200)
        pos2key2(1, 2, k2=100, k1=200)
        def pos2key2dict(p1, p2, *, k1=100, k2, **kwarg): return p1,p2,k1,k2,kwarg
        pos2key2dict(1,2,k2=100,tokwarg1=100,tokwarg2=200)
        pos2key2dict(1,2,tokwarg1=100,tokwarg2=200, k2=100)

        self.assertRaises(SyntaxError, eval, "def f(*): pass")
        self.assertRaises(SyntaxError, eval, "def f(*,): pass")
        self.assertRaises(SyntaxError, eval, "def f(*, **kwds): pass")

        # keyword arguments after *arglist
        def f(*args, **kwargs):
            return args, kwargs
        self.assertEqual(f(1, x=2, *[3, 4], y=5), ((1, 3, 4),
                                                    {'x':2, 'y':5}))
        self.assertEqual(f(1, *(2,3), 4), ((1, 2, 3, 4), {}))
        self.assertRaises(SyntaxError, eval, "f(1, x=2, *(3,4), x=5)")
        self.assertEqual(f(**{'eggs':'scrambled', 'spam':'fried'}),
                         ((), {'eggs':'scrambled', 'spam':'fried'}))
        self.assertEqual(f(spam='fried', **{'eggs':'scrambled'}),
                         ((), {'eggs':'scrambled', 'spam':'fried'}))

        # Check ast errors in *args and *kwargs
        check_syntax_error(self, "f(*g(1=2))")
        check_syntax_error(self, "f(**g(1=2))")

        # argument annotation tests
        def f(x) -> list: pass
        self.assertEqual(f.__annotations__, {'return': list})
        def f(x: int): pass
        self.assertEqual(f.__annotations__, {'x': int})
        def f(x: int, /): pass
        self.assertEqual(f.__annotations__, {'x': int})
        def f(x: int = 34, /): pass
        self.assertEqual(f.__annotations__, {'x': int})
        def f(*x: str): pass
        self.assertEqual(f.__annotations__, {'x': str})
        def f(**x: float): pass
        self.assertEqual(f.__annotations__, {'x': float})
        def f(x, y: 1+2): pass
        self.assertEqual(f.__annotations__, {'y': 3})
        def f(x, y: 1+2, /): pass
        self.assertEqual(f.__annotations__, {'y': 3})
        def f(a, b: 1, c: 2, d): pass
        self.assertEqual(f.__annotations__, {'b': 1, 'c': 2})
        def f(a, b: 1, /, c: 2, d): pass
        self.assertEqual(f.__annotations__, {'b': 1, 'c': 2})
        def f(a, b: 1, c: 2, d, e: 3 = 4, f=5, *g: 6): pass
        self.assertEqual(f.__annotations__,
                         {'b': 1, 'c': 2, 'e': 3, 'g': 6})
        def f(a, b: 1, c: 2, d, e: 3 = 4, f=5, *g: 6, h: 7, i=8, j: 9 = 10,
              **k: 11) -> 12: pass
        self.assertEqual(f.__annotations__,
                         {'b': 1, 'c': 2, 'e': 3, 'g': 6, 'h': 7, 'j': 9,
                          'k': 11, 'return': 12})
        def f(a, b: 1, c: 2, d, e: 3 = 4, f: int = 5, /, *g: 6, h: 7, i=8, j: 9 = 10,
              **k: 11) -> 12: pass
        self.assertEqual(f.__annotations__,
                          {'b': 1, 'c': 2, 'e': 3, 'f': int, 'g': 6, 'h': 7, 'j': 9,
                           'k': 11, 'return': 12})
        # Check for issue #20625 -- annotations mangling
        class Spam:
            def f(self, *, __kw: 1):
                pass
        class Ham(Spam): pass
        self.assertEqual(Spam.f.__annotations__, {'_Spam__kw': 1})
        self.assertEqual(Ham.f.__annotations__, {'_Spam__kw': 1})
        # Check for SF Bug #1697248 - mixing decorators and a return annotation
        def null(x): return x
        @null
        def f(x) -> list: pass
        self.assertEqual(f.__annotations__, {'return': list})

        # Test expressions as decorators (PEP 614):
        @False or null
        def f(x): pass
        @d := null
        def f(x): pass
        @lambda f: null(f)
        def f(x): pass
        @[..., null, ...][1]
        def f(x): pass
        @null(null)(null)
        def f(x): pass
        @[null][0].__call__.__call__
        def f(x): pass

        # test closures with a variety of opargs
        closure = 1
        def f(): return closure
        def f(x=1): return closure
        def f(*, k=1): return closure
        def f() -> int: return closure

        # Check trailing commas are permitted in funcdef argument list
        def f(a,): pass
        def f(*args,): pass
        def f(**kwds,): pass
        def f(a, *args,): pass
        def f(a, **kwds,): pass
        def f(*args, b,): pass
        def f(*, b,): pass
        def f(*args, **kwds,): pass
        def f(a, *args, b,): pass
        def f(a, *, b,): pass
        def f(a, *args, **kwds,): pass
        def f(*args, b, **kwds,): pass
        def f(*, b, **kwds,): pass
        def f(a, *args, b, **kwds,): pass
        def f(a, *, b, **kwds,): pass

    def test_lambdef(self):
        ### lambdef: 'lambda' [varargslist] ':' test
        l1 = lambda : 0
        self.assertEqual(l1(), 0)
        l2 = lambda : a[d] # XXX just testing the expression
        l3 = lambda : [2 < x for x in [-1, 3, 0]]
        self.assertEqual(l3(), [0, 1, 0])
        l4 = lambda x = lambda y = lambda z=1 : z : y() : x()
        self.assertEqual(l4(), 1)
        l5 = lambda x, y, z=2: x + y + z
        self.assertEqual(l5(1, 2), 5)
        self.assertEqual(l5(1, 2, 3), 6)
        check_syntax_error(self, "lambda x: x = 2")
        check_syntax_error(self, "lambda (None,): None")
        l6 = lambda x, y, *, k=20: x+y+k
        self.assertEqual(l6(1,2), 1+2+20)
        self.assertEqual(l6(1,2,k=10), 1+2+10)

        # check that trailing commas are permitted
        l10 = lambda a,: 0
        l11 = lambda *args,: 0
        l12 = lambda **kwds,: 0
        l13 = lambda a, *args,: 0
        l14 = lambda a, **kwds,: 0
        l15 = lambda *args, b,: 0
        l16 = lambda *, b,: 0
        l17 = lambda *args, **kwds,: 0
        l18 = lambda a, *args, b,: 0
        l19 = lambda a, *, b,: 0
        l20 = lambda a, *args, **kwds,: 0
        l21 = lambda *args, b, **kwds,: 0
        l22 = lambda *, b, **kwds,: 0
        l23 = lambda a, *args, b, **kwds,: 0
        l24 = lambda a, *, b, **kwds,: 0


    ### stmt: simple_stmt | compound_stmt
    # Tested below

    def test_simple_stmt(self):
        ### simple_stmt: small_stmt (';' small_stmt)* [';']
        x = 1; pass; del x
        def foo():
            # verify statements that end with semi-colons
            x = 1; pass; del x;
        foo()

    ### small_stmt: expr_stmt | pass_stmt | del_stmt | flow_stmt | import_stmt | global_stmt | access_stmt
    # Tested below

    def test_expr_stmt(self):
        # (exprlist '=')* exprlist
        1
        1, 2, 3
        x = 1
        x = 1, 2, 3
        x = y = z = 1, 2, 3
        x, y, z = 1, 2, 3
        abc = a, b, c = x, y, z = xyz = 1, 2, (3, 4)

        check_syntax_error(self, "x + 1 = 1")
        check_syntax_error(self, "a + 1 = b + 2")

    # Check the heuristic for print & exec covers significant cases
    # As well as placing some limits on false positives
    def test_former_statements_refer_to_builtins(self):
        keywords = "print", "exec"
        # Cases where we want the custom error
        cases = [
            "{} foo",
            "{} {{1:foo}}",
            "if 1: {} foo",
            "if 1: {} {{1:foo}}",
            "if 1:\n    {} foo",
            "if 1:\n    {} {{1:foo}}",
        ]
        for keyword in keywords:
            custom_msg = "call to '{}'".format(keyword)
            for case in cases:
                source = case.format(keyword)
                with self.subTest(source=source):
                    with self.assertRaisesRegex(SyntaxError, custom_msg):
                        exec(source)
                source = source.replace("foo", "(foo.)")
                with self.subTest(source=source):
                    with self.assertRaisesRegex(SyntaxError, "invalid syntax"):
                        exec(source)

    def test_del_stmt(self):
        # 'del' exprlist
        abc = [1,2,3]
        x, y, z = abc
        xyz = x, y, z

        del abc
        del x, y, (z, xyz)

        x, y, z = "xyz"
        del x
        del y,
        del (z)
        del ()

        a, b, c, d, e, f, g = "abcdefg"
        del a, (b, c), (d, (e, f))

        a, b, c, d, e, f, g = "abcdefg"
        del a, [b, c], (d, [e, f])

        abcd = list("abcd")
        del abcd[1:2]

        compile("del a, (b[0].c, (d.e, f.g[1:2])), [h.i.j], ()", "<testcase>", "exec")

    def test_pass_stmt(self):
        # 'pass'
        pass

    # flow_stmt: break_stmt | continue_stmt | return_stmt | raise_stmt
    # Tested below

    def test_break_stmt(self):
        # 'break'
        while 1: break

    def test_continue_stmt(self):
        # 'continue'
        i = 1
        while i: i = 0; continue

        msg = ""
        while not msg:
            msg = "ok"
            try:
                continue
                msg = "continue failed to continue inside try"
            except:
                msg = "continue inside try called except block"
        if msg != "ok":
            self.fail(msg)

        msg = ""
        while not msg:
            msg = "finally block not called"
            try:
                continue
            finally:
                msg = "ok"
        if msg != "ok":
            self.fail(msg)

    def test_break_continue_loop(self):
        # This test warrants an explanation. It is a test specifically for SF bugs
        # #463359 and #462937. The bug is that a 'break' statement executed or
        # exception raised inside a try/except inside a loop, *after* a continue
        # statement has been executed in that loop, will cause the wrong number of
        # arguments to be popped off the stack and the instruction pointer reset to
        # a very small number (usually 0.) Because of this, the following test
        # *must* written as a function, and the tracking vars *must* be function
        # arguments with default values. Otherwise, the test will loop and loop.

        def test_inner(extra_burning_oil = 1, count=0):
            big_hippo = 2
            while big_hippo:
                count += 1
                try:
                    if extra_burning_oil and big_hippo == 1:
                        extra_burning_oil -= 1
                        break
                    big_hippo -= 1
                    continue
                except:
                    raise
            if count > 2 or big_hippo != 1:
                self.fail("continue then break in try/except in loop broken!")
        test_inner()

    def test_return(self):
        # 'return' [testlist_star_expr]
        def g1(): return
        def g2(): return 1
        def g3():
            z = [2, 3]
            return 1, *z

        g1()
        x = g2()
        y = g3()
        self.assertEqual(y, (1, 2, 3), "unparenthesized star expr return")
        check_syntax_error(self, "class foo:return 1")

    def test_break_in_finally(self):
        count = 0
        while count < 2:
            count += 1
            try:
                pass
            finally:
                break
        self.assertEqual(count, 1)

        count = 0
        while count < 2:
            count += 1
            try:
                continue
            finally:
                break
        self.assertEqual(count, 1)

        count = 0
        while count < 2:
            count += 1
            try:
                1/0
            finally:
                break
        self.assertEqual(count, 1)

        for count in [0, 1]:
            self.assertEqual(count, 0)
            try:
                pass
            finally:
                break
        self.assertEqual(count, 0)

        for count in [0, 1]:
            self.assertEqual(count, 0)
            try:
                continue
            finally:
                break
        self.assertEqual(count, 0)

        for count in [0, 1]:
            self.assertEqual(count, 0)
            try:
                1/0
            finally:
                break
        self.assertEqual(count, 0)

    def test_continue_in_finally(self):
        count = 0
        while count < 2:
            count += 1
            try:
                pass
            finally:
                continue
            break
        self.assertEqual(count, 2)

        count = 0
        while count < 2:
            count += 1
            try:
                break
            finally:
                continue
        self.assertEqual(count, 2)

        count = 0
        while count < 2:
            count += 1
            try:
                1/0
            finally:
                continue
            break
        self.assertEqual(count, 2)

        for count in [0, 1]:
            try:
                pass
            finally:
                continue
            break
        self.assertEqual(count, 1)

        for count in [0, 1]:
            try:
                break
            finally:
                continue
        self.assertEqual(count, 1)

        for count in [0, 1]:
            try:
                1/0
            finally:
                continue
            break
        self.assertEqual(count, 1)

    def test_return_in_finally(self):
        def g1():
            try:
                pass
            finally:
                return 1
        self.assertEqual(g1(), 1)

        def g2():
            try:
                return 2
            finally:
                return 3
        self.assertEqual(g2(), 3)

        def g3():
            try:
                1/0
            finally:
                return 4
        self.assertEqual(g3(), 4)

    def test_break_in_finally_after_return(self):
        # See issue #37830
        def g1(x):
            for count in [0, 1]:
                count2 = 0
                while count2 < 20:
                    count2 += 10
                    try:
                        return count + count2
                    finally:
                        if x:
                            break
            return 'end', count, count2
        self.assertEqual(g1(False), 10)
        self.assertEqual(g1(True), ('end', 1, 10))

        def g2(x):
            for count in [0, 1]:
                for count2 in [10, 20]:
                    try:
                        return count + count2
                    finally:
                        if x:
                            break
            return 'end', count, count2
        self.assertEqual(g2(False), 10)
        self.assertEqual(g2(True), ('end', 1, 10))

    def test_continue_in_finally_after_return(self):
        # See issue #37830
        def g1(x):
            count = 0
            while count < 100:
                count += 1
                try:
                    return count
                finally:
                    if x:
                        continue
            return 'end', count
        self.assertEqual(g1(False), 1)
        self.assertEqual(g1(True), ('end', 100))

        def g2(x):
            for count in [0, 1]:
                try:
                    return count
                finally:
                    if x:
                        continue
            return 'end', count
        self.assertEqual(g2(False), 0)
        self.assertEqual(g2(True), ('end', 1))

    def test_yield(self):
        # Allowed as standalone statement
        def g(): yield 1
        def g(): yield from ()
        # Allowed as RHS of assignment
        def g(): x = yield 1
        def g(): x = yield from ()
        # Ordinary yield accepts implicit tuples
        def g(): yield 1, 1
        def g(): x = yield 1, 1
        # 'yield from' does not
        check_syntax_error(self, "def g(): yield from (), 1")
        check_syntax_error(self, "def g(): x = yield from (), 1")
        # Requires parentheses as subexpression
        def g(): 1, (yield 1)
        def g(): 1, (yield from ())
        check_syntax_error(self, "def g(): 1, yield 1")
        check_syntax_error(self, "def g(): 1, yield from ()")
        # Requires parentheses as call argument
        def g(): f((yield 1))
        def g(): f((yield 1), 1)
        def g(): f((yield from ()))
        def g(): f((yield from ()), 1)
        # Do not require parenthesis for tuple unpacking
        def g(): rest = 4, 5, 6; yield 1, 2, 3, *rest
        self.assertEqual(list(g()), [(1, 2, 3, 4, 5, 6)])
        check_syntax_error(self, "def g(): f(yield 1)")
        check_syntax_error(self, "def g(): f(yield 1, 1)")
        check_syntax_error(self, "def g(): f(yield from ())")
        check_syntax_error(self, "def g(): f(yield from (), 1)")
        # Not allowed at top level
        check_syntax_error(self, "yield")
        check_syntax_error(self, "yield from")
        # Not allowed at class scope
        check_syntax_error(self, "class foo:yield 1")
        check_syntax_error(self, "class foo:yield from ()")
        # Check annotation refleak on SyntaxError
        check_syntax_error(self, "def g(a:(yield)): pass")

    def test_yield_in_comprehensions(self):
        # Check yield in comprehensions
        def g(): [x for x in [(yield 1)]]
        def g(): [x for x in [(yield from ())]]

        check = self.check_syntax_error
        check("def g(): [(yield x) for x in ()]",
              "'yield' inside list comprehension")
        check("def g(): [x for x in () if not (yield x)]",
              "'yield' inside list comprehension")
        check("def g(): [y for x in () for y in [(yield x)]]",
              "'yield' inside list comprehension")
        check("def g(): {(yield x) for x in ()}",
              "'yield' inside set comprehension")
        check("def g(): {(yield x): x for x in ()}",
              "'yield' inside dict comprehension")
        check("def g(): {x: (yield x) for x in ()}",
              "'yield' inside dict comprehension")
        check("def g(): ((yield x) for x in ())",
              "'yield' inside generator expression")
        check("def g(): [(yield from x) for x in ()]",
              "'yield' inside list comprehension")
        check("class C: [(yield x) for x in ()]",
              "'yield' inside list comprehension")
        check("[(yield x) for x in ()]",
              "'yield' inside list comprehension")

    def test_raise(self):
        # 'raise' test [',' test]
        try: raise RuntimeError('just testing')
        except RuntimeError: pass
        try: raise KeyboardInterrupt
        except KeyboardInterrupt: pass

    def test_import(self):
        # 'import' dotted_as_names
        import sys
        import time, sys
        # 'from' dotted_name 'import' ('*' | '(' import_as_names ')' | import_as_names)
        from time import time
        from time import (time)
        # not testable inside a function, but already done at top of the module
        # from sys import *
        from sys import path, argv
        from sys import (path, argv)
        from sys import (path, argv,)

    def test_global(self):
        # 'global' NAME (',' NAME)*
        global a
        global a, b
        global one, two, three, four, five, six, seven, eight, nine, ten

    def test_nonlocal(self):
        # 'nonlocal' NAME (',' NAME)*
        x = 0
        y = 0
        def f():
            nonlocal x
            nonlocal x, y

    def test_assert(self):
        # assertTruestmt: 'assert' test [',' test]
        assert 1
        assert 1, 1
        assert lambda x:x
        assert 1, lambda x:x+1

        try:
            assert True
        except AssertionError as e:
            self.fail("'assert True' should not have raised an AssertionError")

        try:
            assert True, 'this should always pass'
        except AssertionError as e:
            self.fail("'assert True, msg' should not have "
                      "raised an AssertionError")

    # these tests fail if python is run with -O, so check __debug__
    @unittest.skipUnless(__debug__, "Won't work if __debug__ is False")
    def test_assert_failures(self):
        try:
            assert 0, "msg"
        except AssertionError as e:
            self.assertEqual(e.args[0], "msg")
        else:
            self.fail("AssertionError not raised by assert 0")

        try:
            assert False
        except AssertionError as e:
            self.assertEqual(len(e.args), 0)
        else:
            self.fail("AssertionError not raised by 'assert False'")

    def test_assert_syntax_warnings(self):
        # Ensure that we warn users if they provide a non-zero length tuple as
        # the assertion test.
        self.check_syntax_warning('assert(x, "msg")',
                                  'assertion is always true')
        self.check_syntax_warning('assert(False, "msg")',
                                  'assertion is always true')
        self.check_syntax_warning('assert(False,)',
                                  'assertion is always true')

        with self.check_no_warnings(category=SyntaxWarning):
            compile('assert x, "msg"', '<testcase>', 'exec')
            compile('assert False, "msg"', '<testcase>', 'exec')

    def test_assert_warning_promotes_to_syntax_error(self):
        # If SyntaxWarning is configured to be an error, it actually raises a
        # SyntaxError.
        # https://bugs.python.org/issue35029
        with warnings.catch_warnings():
            warnings.simplefilter('error', SyntaxWarning)
            try:
                compile('assert x, "msg" ', '<testcase>', 'exec')
            except SyntaxError:
                self.fail('SyntaxError incorrectly raised for \'assert x, "msg"\'')
            with self.assertRaises(SyntaxError):
                compile('assert(x, "msg")', '<testcase>', 'exec')
            with self.assertRaises(SyntaxError):
                compile('assert(False, "msg")', '<testcase>', 'exec')
            with self.assertRaises(SyntaxError):
                compile('assert(False,)', '<testcase>', 'exec')


    ### compound_stmt: if_stmt | while_stmt | for_stmt | try_stmt | funcdef | classdef
    # Tested below

    def test_if(self):
        # 'if' test ':' suite ('elif' test ':' suite)* ['else' ':' suite]
        if 1: pass
        if 1: pass
        else: pass
        if 0: pass
        elif 0: pass
        if 0: pass
        elif 0: pass
        elif 0: pass
        elif 0: pass
        else: pass

    def test_while(self):
        # 'while' test ':' suite ['else' ':' suite]
        while 0: pass
        while 0: pass
        else: pass

        # Issue1920: "while 0" is optimized away,
        # ensure that the "else" clause is still present.
        x = 0
        while 0:
            x = 1
        else:
            x = 2
        self.assertEqual(x, 2)

    def test_for(self):
        # 'for' exprlist 'in' exprlist ':' suite ['else' ':' suite]
        for i in 1, 2, 3: pass
        for i, j, k in (): pass
        else: pass
        class Squares:
            def __init__(self, max):
                self.max = max
                self.sofar = []
            def __len__(self): return len(self.sofar)
            def __getitem__(self, i):
                if not 0 <= i < self.max: raise IndexError
                n = len(self.sofar)
                while n <= i:
                    self.sofar.append(n*n)
                    n = n+1
                return self.sofar[i]
        n = 0
        for x in Squares(10): n = n+x
        if n != 285:
            self.fail('for over growing sequence')

        result = []
        for x, in [(1,), (2,), (3,)]:
            result.append(x)
        self.assertEqual(result, [1, 2, 3])

        result = []
        a = b = c = [1, 2, 3]
        for x in *a, *b, *c:
            result.append(x)
        self.assertEqual(result, 3 * a)

    def test_try(self):
        ### try_stmt: 'try' ':' suite (except_clause ':' suite)+ ['else' ':' suite]
        ###         | 'try' ':' suite 'finally' ':' suite
        ### except_clause: 'except' [expr ['as' NAME]]
        try:
            1/0
        except ZeroDivisionError:
            pass
        else:
            pass
        try: 1/0
        except EOFError: pass
        except TypeError as msg: pass
        except: pass
        else: pass
        try: 1/0
        except (EOFError, TypeError, ZeroDivisionError): pass
        try: 1/0
        except (EOFError, TypeError, ZeroDivisionError) as msg: pass
        try: pass
        finally: pass
        with self.assertRaises(SyntaxError):
            compile("try:\n    pass\nexcept Exception as a.b:\n    pass", "?", "exec")
            compile("try:\n    pass\nexcept Exception as a[b]:\n    pass", "?", "exec")

    def test_try_star(self):
        ### try_stmt: 'try': suite (except_star_clause : suite) + ['else' ':' suite]
        ### except_star_clause: 'except*' expr ['as' NAME]
        try:
            1/0
        except* ZeroDivisionError:
            pass
        else:
            pass
        try: 1/0
        except* EOFError: pass
        except* ZeroDivisionError as msg: pass
        else: pass
        try: 1/0
        except* (EOFError, TypeError, ZeroDivisionError): pass
        try: 1/0
        except* (EOFError, TypeError, ZeroDivisionError) as msg: pass
        try: pass
        finally: pass
        with self.assertRaises(SyntaxError):
            compile("try:\n    pass\nexcept* Exception as a.b:\n    pass", "?", "exec")
            compile("try:\n    pass\nexcept* Exception as a[b]:\n    pass", "?", "exec")
            compile("try:\n    pass\nexcept*:\n    pass", "?", "exec")

    def test_suite(self):
        # simple_stmt | NEWLINE INDENT NEWLINE* (stmt NEWLINE*)+ DEDENT
        if 1: pass
        if 1:
            pass
        if 1:
            #
            #
            #
            pass
            pass
            #
            pass
            #

    def test_test(self):
        ### and_test ('or' and_test)*
        ### and_test: not_test ('and' not_test)*
        ### not_test: 'not' not_test | comparison
        if not 1: pass
        if 1 and 1: pass
        if 1 or 1: pass
        if not not not 1: pass
        if not 1 and 1 and 1: pass
        if 1 and 1 or 1 and 1 and 1 or not 1 and 1: pass

    def test_comparison(self):
        ### comparison: expr (comp_op expr)*
        ### comp_op: '<'|'>'|'=='|'>='|'<='|'!='|'in'|'not' 'in'|'is'|'is' 'not'
        if 1: pass
        x = (1 == 1)
        if 1 == 1: pass
        if 1 != 1: pass
        if 1 < 1: pass
        if 1 > 1: pass
        if 1 <= 1: pass
        if 1 >= 1: pass
        if x is x: pass
        if x is not x: pass
        if 1 in (): pass
        if 1 not in (): pass
        if 1 < 1 > 1 == 1 >= 1 <= 1 != 1 in 1 not in x is x is not x: pass

    def test_comparison_is_literal(self):
        def check(test, msg):
            self.check_syntax_warning(test, msg)

        check('x is 1', '"is" with \'int\' literal')
        check('x is "thing"', '"is" with \'str\' literal')
        check('1 is x', '"is" with \'int\' literal')
        check('x is y is 1', '"is" with \'int\' literal')
        check('x is not 1', '"is not" with \'int\' literal')
        check('x is not (1, 2)', '"is not" with \'tuple\' literal')
        check('(1, 2) is not x', '"is not" with \'tuple\' literal')

        check('None is 1', '"is" with \'int\' literal')
        check('1 is None', '"is" with \'int\' literal')

        check('x == 3 is y', '"is" with \'int\' literal')
        check('x == "thing" is y', '"is" with \'str\' literal')

        with warnings.catch_warnings():
            warnings.simplefilter('error', SyntaxWarning)
            compile('x is None', '<testcase>', 'exec')
            compile('x is False', '<testcase>', 'exec')
            compile('x is True', '<testcase>', 'exec')
            compile('x is ...', '<testcase>', 'exec')
            compile('None is x', '<testcase>', 'exec')
            compile('False is x', '<testcase>', 'exec')
            compile('True is x', '<testcase>', 'exec')
            compile('... is x', '<testcase>', 'exec')

    def test_warn_missed_comma(self):
        def check(test):
            self.check_syntax_warning(test, msg)

        msg=r'is not callable; perhaps you missed a comma\?'
        check('[(1, 2) (3, 4)]')
        check('[(x, y) (3, 4)]')
        check('[[1, 2] (3, 4)]')
        check('[{1, 2} (3, 4)]')
        check('[{1: 2} (3, 4)]')
        check('[[i for i in range(5)] (3, 4)]')
        check('[{i for i in range(5)} (3, 4)]')
        check('[(i for i in range(5)) (3, 4)]')
        check('[{i: i for i in range(5)} (3, 4)]')
        check('[f"{x}" (3, 4)]')
        check('[f"x={x}" (3, 4)]')
        check('["abc" (3, 4)]')
        check('[b"abc" (3, 4)]')
        check('[123 (3, 4)]')
        check('[12.3 (3, 4)]')
        check('[12.3j (3, 4)]')
        check('[None (3, 4)]')
        check('[True (3, 4)]')
        check('[... (3, 4)]')

        msg=r'is not subscriptable; perhaps you missed a comma\?'
        check('[{1, 2} [i, j]]')
        check('[{i for i in range(5)} [i, j]]')
        check('[(i for i in range(5)) [i, j]]')
        check('[(lambda x, y: x) [i, j]]')
        check('[123 [i, j]]')
        check('[12.3 [i, j]]')
        check('[12.3j [i, j]]')
        check('[None [i, j]]')
        check('[True [i, j]]')
        check('[... [i, j]]')

        msg=r'indices must be integers or slices, not tuple; perhaps you missed a comma\?'
        check('[(1, 2) [i, j]]')
        check('[(x, y) [i, j]]')
        check('[[1, 2] [i, j]]')
        check('[[i for i in range(5)] [i, j]]')
        check('[f"{x}" [i, j]]')
        check('[f"x={x}" [i, j]]')
        check('["abc" [i, j]]')
        check('[b"abc" [i, j]]')

        msg=r'indices must be integers or slices, not tuple;'
        check('[[1, 2] [3, 4]]')
        msg=r'indices must be integers or slices, not list;'
        check('[[1, 2] [[3, 4]]]')
        check('[[1, 2] [[i for i in range(5)]]]')
        msg=r'indices must be integers or slices, not set;'
        check('[[1, 2] [{3, 4}]]')
        check('[[1, 2] [{i for i in range(5)}]]')
        msg=r'indices must be integers or slices, not dict;'
        check('[[1, 2] [{3: 4}]]')
        check('[[1, 2] [{i: i for i in range(5)}]]')
        msg=r'indices must be integers or slices, not generator;'
        check('[[1, 2] [(i for i in range(5))]]')
        msg=r'indices must be integers or slices, not function;'
        check('[[1, 2] [(lambda x, y: x)]]')
        msg=r'indices must be integers or slices, not str;'
        check('[[1, 2] [f"{x}"]]')
        check('[[1, 2] [f"x={x}"]]')
        check('[[1, 2] ["abc"]]')
        msg=r'indices must be integers or slices, not'
        check('[[1, 2] [b"abc"]]')
        check('[[1, 2] [12.3]]')
        check('[[1, 2] [12.3j]]')
        check('[[1, 2] [None]]')
        check('[[1, 2] [...]]')

        with warnings.catch_warnings():
            warnings.simplefilter('error', SyntaxWarning)
            compile('[(lambda x, y: x) (3, 4)]', '<testcase>', 'exec')
            compile('[[1, 2] [i]]', '<testcase>', 'exec')
            compile('[[1, 2] [0]]', '<testcase>', 'exec')
            compile('[[1, 2] [True]]', '<testcase>', 'exec')
            compile('[[1, 2] [1:2]]', '<testcase>', 'exec')
            compile('[{(1, 2): 3} [i, j]]', '<testcase>', 'exec')

    def test_binary_mask_ops(self):
        x = 1 & 1
        x = 1 ^ 1
        x = 1 | 1

    def test_shift_ops(self):
        x = 1 << 1
        x = 1 >> 1
        x = 1 << 1 >> 1

    def test_additive_ops(self):
        x = 1
        x = 1 + 1
        x = 1 - 1 - 1
        x = 1 - 1 + 1 - 1 + 1

    def test_multiplicative_ops(self):
        x = 1 * 1
        x = 1 / 1
        x = 1 % 1
        x = 1 / 1 * 1 % 1

    def test_unary_ops(self):
        x = +1
        x = -1
        x = ~1
        x = ~1 ^ 1 & 1 | 1 & 1 ^ -1
        x = -1*1/1 + 1*1 - ---1*1

    def test_selectors(self):
        ### trailer: '(' [testlist] ')' | '[' subscript ']' | '.' NAME
        ### subscript: expr | [expr] ':' [expr]

        import sys, time
        c = sys.path[0]
        x = time.time()
        x = sys.modules['time'].time()
        a = '01234'
        c = a[0]
        c = a[-1]
        s = a[0:5]
        s = a[:5]
        s = a[0:]
        s = a[:]
        s = a[-5:]
        s = a[:-1]
        s = a[-4:-3]
        # A rough test of SF bug 1333982.  https://bugs.python.org/issue1333982
        # The testing here is fairly incomplete.
        # Test cases should include: commas with 1 and 2 colons
        d = {}
        d[1] = 1
        d[1,] = 2
        d[1,2] = 3
        d[1,2,3] = 4
        L = list(d)
        L.sort(key=lambda x: (type(x).__name__, x))
        self.assertEqual(str(L), '[1, (1,), (1, 2), (1, 2, 3)]')

    def test_atoms(self):
        ### atom: '(' [testlist] ')' | '[' [testlist] ']' | '{' [dictsetmaker] '}' | NAME | NUMBER | STRING
        ### dictsetmaker: (test ':' test (',' test ':' test)* [',']) | (test (',' test)* [','])

        x = (1)
        x = (1 or 2 or 3)
        x = (1 or 2 or 3, 2, 3)

        x = []
        x = [1]
        x = [1 or 2 or 3]
        x = [1 or 2 or 3, 2, 3]
        x = []

        x = {}
        x = {'one': 1}
        x = {'one': 1,}
        x = {'one' or 'two': 1 or 2}
        x = {'one': 1, 'two': 2}
        x = {'one': 1, 'two': 2,}
        x = {'one': 1, 'two': 2, 'three': 3, 'four': 4, 'five': 5, 'six': 6}

        x = {'one'}
        x = {'one', 1,}
        x = {'one', 'two', 'three'}
        x = {2, 3, 4,}

        x = x
        x = 'x'
        x = 123

    ### exprlist: expr (',' expr)* [',']
    ### testlist: test (',' test)* [',']
    # These have been exercised enough above

    def test_classdef(self):
        # 'class' NAME ['(' [testlist] ')'] ':' suite
        class B: pass
        class B2(): pass
        class C1(B): pass
        class C2(B): pass
        class D(C1, C2, B): pass
        class C:
            def meth1(self): pass
            def meth2(self, arg): pass
            def meth3(self, a1, a2): pass

        # decorator: '@' namedexpr_test NEWLINE
        # decorators: decorator+
        # decorated: decorators (classdef | funcdef)
        def class_decorator(x): return x
        @class_decorator
        class G: pass

        # Test expressions as decorators (PEP 614):
        @False or class_decorator
        class H: pass
        @d := class_decorator
        class I: pass
        @lambda c: class_decorator(c)
        class J: pass
        @[..., class_decorator, ...][1]
        class K: pass
        @class_decorator(class_decorator)(class_decorator)
        class L: pass
        @[class_decorator][0].__call__.__call__
        class M: pass

    def test_dictcomps(self):
        # dictorsetmaker: ( (test ':' test (comp_for |
        #                                   (',' test ':' test)* [','])) |
        #                   (test (comp_for | (',' test)* [','])) )
        nums = [1, 2, 3]
        self.assertEqual({i:i+1 for i in nums}, {1: 2, 2: 3, 3: 4})

    def test_listcomps(self):
        # list comprehension tests
        nums = [1, 2, 3, 4, 5]
        strs = ["Apple", "Banana", "Coconut"]
        spcs = ["  Apple", " Banana ", "Coco  nut  "]

        self.assertEqual([s.strip() for s in spcs], ['Apple', 'Banana', 'Coco  nut'])
        self.assertEqual([3 * x for x in nums], [3, 6, 9, 12, 15])
        self.assertEqual([x for x in nums if x > 2], [3, 4, 5])
        self.assertEqual([(i, s) for i in nums for s in strs],
                         [(1, 'Apple'), (1, 'Banana'), (1, 'Coconut'),
                          (2, 'Apple'), (2, 'Banana'), (2, 'Coconut'),
                          (3, 'Apple'), (3, 'Banana'), (3, 'Coconut'),
                          (4, 'Apple'), (4, 'Banana'), (4, 'Coconut'),
                          (5, 'Apple'), (5, 'Banana'), (5, 'Coconut')])
        self.assertEqual([(i, s) for i in nums for s in [f for f in strs if "n" in f]],
                         [(1, 'Banana'), (1, 'Coconut'), (2, 'Banana'), (2, 'Coconut'),
                          (3, 'Banana'), (3, 'Coconut'), (4, 'Banana'), (4, 'Coconut'),
                          (5, 'Banana'), (5, 'Coconut')])
        self.assertEqual([(lambda a:[a**i for i in range(a+1)])(j) for j in range(5)],
                         [[1], [1, 1], [1, 2, 4], [1, 3, 9, 27], [1, 4, 16, 64, 256]])

        def test_in_func(l):
            return [0 < x < 3 for x in l if x > 2]

        self.assertEqual(test_in_func(nums), [False, False, False])

        def test_nested_front():
            self.assertEqual([[y for y in [x, x + 1]] for x in [1,3,5]],
                             [[1, 2], [3, 4], [5, 6]])

        test_nested_front()

        check_syntax_error(self, "[i, s for i in nums for s in strs]")
        check_syntax_error(self, "[x if y]")

        suppliers = [
          (1, "Boeing"),
          (2, "Ford"),
          (3, "Macdonalds")
        ]

        parts = [
          (10, "Airliner"),
          (20, "Engine"),
          (30, "Cheeseburger")
        ]

        suppart = [
          (1, 10), (1, 20), (2, 20), (3, 30)
        ]

        x = [
          (sname, pname)
            for (sno, sname) in suppliers
              for (pno, pname) in parts
                for (sp_sno, sp_pno) in suppart
                  if sno == sp_sno and pno == sp_pno
        ]

        self.assertEqual(x, [('Boeing', 'Airliner'), ('Boeing', 'Engine'), ('Ford', 'Engine'),
                             ('Macdonalds', 'Cheeseburger')])

    def test_genexps(self):
        # generator expression tests
        g = ([x for x in range(10)] for x in range(1))
        self.assertEqual(next(g), [x for x in range(10)])
        try:
            next(g)
            self.fail('should produce StopIteration exception')
        except StopIteration:
            pass

        a = 1
        try:
            g = (a for d in a)
            next(g)
            self.fail('should produce TypeError')
        except TypeError:
            pass

        self.assertEqual(list((x, y) for x in 'abcd' for y in 'abcd'), [(x, y) for x in 'abcd' for y in 'abcd'])
        self.assertEqual(list((x, y) for x in 'ab' for y in 'xy'), [(x, y) for x in 'ab' for y in 'xy'])

        a = [x for x in range(10)]
        b = (x for x in (y for y in a))
        self.assertEqual(sum(b), sum([x for x in range(10)]))

        self.assertEqual(sum(x**2 for x in range(10)), sum([x**2 for x in range(10)]))
        self.assertEqual(sum(x*x for x in range(10) if x%2), sum([x*x for x in range(10) if x%2]))
        self.assertEqual(sum(x for x in (y for y in range(10))), sum([x for x in range(10)]))
        self.assertEqual(sum(x for x in (y for y in (z for z in range(10)))), sum([x for x in range(10)]))
        self.assertEqual(sum(x for x in [y for y in (z for z in range(10))]), sum([x for x in range(10)]))
        self.assertEqual(sum(x for x in (y for y in (z for z in range(10) if True)) if True), sum([x for x in range(10)]))
        self.assertEqual(sum(x for x in (y for y in (z for z in range(10) if True) if False) if True), 0)
        check_syntax_error(self, "foo(x for x in range(10), 100)")
        check_syntax_error(self, "foo(100, x for x in range(10))")

    def test_comprehension_specials(self):
        # test for outmost iterable precomputation
        x = 10; g = (i for i in range(x)); x = 5
        self.assertEqual(len(list(g)), 10)

        # This should hold, since we're only precomputing outmost iterable.
        x = 10; t = False; g = ((i,j) for i in range(x) if t for j in range(x))
        x = 5; t = True;
        self.assertEqual([(i,j) for i in range(10) for j in range(5)], list(g))

        # Grammar allows multiple adjacent 'if's in listcomps and genexps,
        # even though it's silly. Make sure it works (ifelse broke this.)
        self.assertEqual([ x for x in range(10) if x % 2 if x % 3 ], [1, 5, 7])
        self.assertEqual(list(x for x in range(10) if x % 2 if x % 3), [1, 5, 7])

        # verify unpacking single element tuples in listcomp/genexp.
        self.assertEqual([x for x, in [(4,), (5,), (6,)]], [4, 5, 6])
        self.assertEqual(list(x for x, in [(7,), (8,), (9,)]), [7, 8, 9])

    def test_with_statement(self):
        class manager(object):
            def __enter__(self):
                return (1, 2)
            def __exit__(self, *args):
                pass

        with manager():
            pass
        with manager() as x:
            pass
        with manager() as (x, y):
            pass
        with manager(), manager():
            pass
        with manager() as x, manager() as y:
            pass
        with manager() as x, manager():
            pass

        with (
            manager()
        ):
            pass

        with (
            manager() as x
        ):
            pass

        with (
            manager() as (x, y),
            manager() as z,
        ):
            pass

        with (
            manager(),
            manager()
        ):
            pass

        with (
            manager() as x,
            manager() as y
        ):
            pass

        with (
            manager() as x,
            manager()
        ):
            pass

        with (
            manager() as x,
            manager() as y,
            manager() as z,
        ):
            pass

        with (
            manager() as x,
            manager() as y,
            manager(),
        ):
            pass

    def test_if_else_expr(self):
        # Test ifelse expressions in various cases
        def _checkeval(msg, ret):
            "helper to check that evaluation of expressions is done correctly"
            print(msg)
            return ret

        # the next line is not allowed anymore
        #self.assertEqual([ x() for x in lambda: True, lambda: False if x() ], [True])
        self.assertEqual([ x() for x in (lambda: True, lambda: False) if x() ], [True])
        self.assertEqual([ x(False) for x in (lambda x: False if x else True, lambda x: True if x else False) if x(False) ], [True])
        self.assertEqual((5 if 1 else _checkeval("check 1", 0)), 5)
        self.assertEqual((_checkeval("check 2", 0) if 0 else 5), 5)
        self.assertEqual((5 and 6 if 0 else 1), 1)
        self.assertEqual(((5 and 6) if 0 else 1), 1)
        self.assertEqual((5 and (6 if 1 else 1)), 6)
        self.assertEqual((0 or _checkeval("check 3", 2) if 0 else 3), 3)
        self.assertEqual((1 or _checkeval("check 4", 2) if 1 else _checkeval("check 5", 3)), 1)
        self.assertEqual((0 or 5 if 1 else _checkeval("check 6", 3)), 5)
        self.assertEqual((not 5 if 1 else 1), False)
        self.assertEqual((not 5 if 0 else 1), 1)
        self.assertEqual((6 + 1 if 1 else 2), 7)
        self.assertEqual((6 - 1 if 1 else 2), 5)
        self.assertEqual((6 * 2 if 1 else 4), 12)
        self.assertEqual((6 / 2 if 1 else 3), 3)
        self.assertEqual((6 < 4 if 0 else 2), 2)

    def test_paren_evaluation(self):
        self.assertEqual(16 // (4 // 2), 8)
        self.assertEqual((16 // 4) // 2, 2)
        self.assertEqual(16 // 4 // 2, 2)
        x = 2
        y = 3
        self.assertTrue(False is (x is y))
        self.assertFalse((False is x) is y)
        self.assertFalse(False is x is y)

    def test_matrix_mul(self):
        # This is not intended to be a comprehensive test, rather just to be few
        # samples of the @ operator in test_grammar.py.
        class M:
            def __matmul__(self, o):
                return 4
            def __imatmul__(self, o):
                self.other = o
                return self
        m = M()
        self.assertEqual(m @ m, 4)
        m @= 42
        self.assertEqual(m.other, 42)

    def test_async_await(self):
        async def test():
            def sum():
                pass
            if 1:
                await someobj()

        self.assertEqual(test.__name__, 'test')
        self.assertTrue(bool(test.__code__.co_flags & inspect.CO_COROUTINE))

        def decorator(func):
            setattr(func, '_marked', True)
            return func

        @decorator
        async def test2():
            return 22
        self.assertTrue(test2._marked)
        self.assertEqual(test2.__name__, 'test2')
        self.assertTrue(bool(test2.__code__.co_flags & inspect.CO_COROUTINE))

    def test_async_for(self):
        class Done(Exception): pass

        class AIter:
            def __aiter__(self):
                return self
            async def __anext__(self):
                raise StopAsyncIteration

        async def foo():
            async for i in AIter():
                pass
            async for i, j in AIter():
                pass
            async for i in AIter():
                pass
            else:
                pass
            raise Done

        with self.assertRaises(Done):
            foo().send(None)

    def test_async_with(self):
        class Done(Exception): pass

        class manager:
            async def __aenter__(self):
                return (1, 2)
            async def __aexit__(self, *exc):
                return False

        async def foo():
            async with manager():
                pass
            async with manager() as x:
                pass
            async with manager() as (x, y):
                pass
            async with manager(), manager():
                pass
            async with manager() as x, manager() as y:
                pass
            async with manager() as x, manager():
                pass
            raise Done

        with self.assertRaises(Done):
            foo().send(None)


if __name__ == '__main__':
    unittest.main()