deftest_warning(self):

withwarnings_helper.check_warnings(

('"is" witha literal',SyntaxWarning),

('"is" with\'str\' literal',SyntaxWarning),

("invalid escape sequence",SyntaxWarning),

)asw:

compile_command(r"'\e' is 0")

check(f"[{num}for x in ()]")

check(f"{num}spam",error=True)

withself.assertWarnsRegex(SyntaxWarning,r'invalid \w+ literal'):

compile(f"{num}is x","<testcase>","eval")

withwarnings.catch_warnings():

warnings.filterwarnings('ignore','"is" with a literal',

SyntaxWarning)

withself.assertWarnsRegex(SyntaxWarning,

r'invalid \w+ literal'):

compile(f"{num}is x","<testcase>","eval")

warnings.simplefilter('error',SyntaxWarning)

withself.assertRaisesRegex(SyntaxError,

r'invalid \w+ literal'):

if1<1>1==1>=1<=1!=1in1notinxisxisnotx:pass

deftest_comparison_is_literal(self):

defcheck(test,msg='"is" with a literal'):

defcheck(test,msg):

self.check_syntax_warning(test,msg)

check('x is 1')

check('x is "thing"')

check('1 is x')

check('x is y is 1')

check('x is not 1','"is not" with a literal')

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')

withwarnings.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')

deftest_warn_missed_comma(self):

defcheck(test):

Clarify:exc:`SyntaxWarning` with literal ``is`` comparison by specifying which literal is problematic, since comparisons using ``is`` with e.g. None and bool literals are idiomatic.

||value==Py_Ellipsis);

}

staticPyTypeObject*infer_type(expr_tye);

{

Py_ssize_ti,n;

boolleft=check_is_arg(e->v.Compare.left);

expr_tyleft_expr=e->v.Compare.left;

n=asdl_seq_LEN(e->v.Compare.ops);

for (i=0;i<n;i++) {

cmpop_tyop= (cmpop_ty)asdl_seq_GET(e->v.Compare.ops,i);

boolright=check_is_arg((expr_ty)asdl_seq_GET(e->v.Compare.comparators,i));

expr_tyright_expr= (expr_ty)asdl_seq_GET(e->v.Compare.comparators,i);

boolright=check_is_arg(right_expr);

if (op==Is||op==IsNot) {

if (!right|| !left) {

constchar*msg= (op==Is)

?"\"is\" with a literal. Did you mean \"==\"?"

:"\"is not\" with a literal. Did you mean \"!=\"?";

returncompiler_warn(c,LOC(e),msg);

?"\"is\" with '%.200s' literal. Did you mean \"==\"?"

:"\"is not\" with '%.200s' literal. Did you mean \"!=\"?";

expr_tyliteral= !left ?left_expr :right_expr;

returncompiler_warn(

c,LOC(e),msg,infer_type(literal)->tp_name

);

}

}

left=right;

left_expr=right_expr;

}

returnSUCCESS;

}