Certain sys.monitoring "not taken" branches in a `for` loop not showing correctly

Bug report

Bug description:

With the code from PR 122564, the destinations of the "not taken" branches out of lines 2 and 3 show as going out of scope, rather than the correct line 6. Additionally, the ("taken") branch into if's block also shows as going out of scope:

def foo():
    for v in [1, 2]:
        if v > 0:
            x += v

    return x

Results:

  1          0       RESUME                   0

  2          2       LOAD_CONST               1 ((1, 2))
             4       GET_ITER
      L1:    6       FOR_ITER                18 (to L3)
            10       NOT_TAKEN
            12       STORE_FAST               0 (v)

  3         14       LOAD_FAST                0 (v)
            16       LOAD_CONST               2 (0)
            18       COMPARE_OP             148 (bool(>))
            22       POP_JUMP_IF_TRUE         2 (to L2)
            26       JUMP_BACKWARD           12 (to L1)
      L2:   30       NOT_TAKEN

  4         32       LOAD_FAST_CHECK          1 (x)
            34       LOAD_FAST                0 (v)
            36       BINARY_OP               13 (+=)
            40       STORE_FAST               1 (x)
            42       JUMP_BACKWARD           20 (to L1)

  2   L3:   46       END_FOR
            48       POP_TOP

  6         50       LOAD_FAST_CHECK          1 (x)
            52       RETURN_VALUE
'foo' branches:
    ex10.py 2:13-2:19 "[1, 2]" (foo@6) -> 2:8-2:9 "v" (foo@12) [for -> block]
    ex10.py 2:13-2:19 "[1, 2]" (foo@6) -> 2:13-2:19 "[1, 2]" (foo@46) [for -> out]
    ex10.py 3:11-3:16 "v > 0" (foo@22) -> 3:11-3:16 "v > 0" (foo@28) [if/while -> out]
    ex10.py 3:11-3:16 "v > 0" (foo@22) -> 3:11-3:16 "v > 0" (foo@30) [if/while -> out]

@markshannon @nedbat

CPython versions tested on:

CPython main branch

Operating systems tested on:

macOS

使用 for-loop 示例和 PR 122564 中的代码重现该报告，然后跟踪 sys.monitoring 如何记录未采取的分支以及进入 if 块的分支。完成的标准是这些目标指向第 6 行或正确的作用域内位置，而不是被报告为超出作用域。