

def test_diff_no_eval_derivative():

    class My(Expr):

        def __new__(cls, x):
            return Expr.__new__(cls, x)
    (x, y) = symbols('x y')
    assert (My(x).diff(x).func is Derivative)
    assert (My(x).diff(x) == 0)

dataset/ETHPy150Open sympy/sympy/sympy/core/tests/test_diff.py test_diff_no_eval_derivative/VarMisuse@78/97 `y`->`x`