`f(kw=a, *b)` with keyword argument before star arguments isn’t evaluated left-to-right

def f(a, kw):
    pass

f(kw=print(1), *[print(2)])

In Python 3.4.10 and earlier, this prints 1 then 2, but in Python 3.5.0 and later, this prints 2 then 1.

This seems like a bug of some kind. Given that ast.parse() doesn’t distinguish between f(kw=a, *b) and f(*b, kw=a), perhaps the bug is that a keyword argument is allowed before star arguments at all—we already disallow f(kw=a, b), f(**a, b), and f(**a, *b).

先在受影響的 Python 版本上重現提供的 f(kw=print(1), *[print(2)]) 範例，接著追蹤 CPython 如何剖析及評估包含關鍵字引數和星號引數的呼叫。當行為獲得一致修正，或在選定的解決方案是拒絕無效引數順序的情況下拒絕該順序時，即表示完成；該 issue 未指定原始碼檔案或測試。