z3 LastIndexOf returns 错误结果？

Question

z3py 的 LastIndexOf 应该 return “字符串中子字符串的最后一个索引”。但是，当子字符串位于字符串的末尾时，似乎 return 是错误的结果，例如：

>>> import z3
>>> def check_lastindexof(s, sub_list):
...     for c in sub_list:
...         z_index = z3.simplify(z3.LastIndexOf(s, c))
...         v_index = s.rindex(c)
...         try:
...             assert z_index == v_index
...         except Exception as e:
...             print(f'{c: <6} FAILED expected: {v_index: >2}, got: {z_index}')
...
>>>
>>> s = 'abcdefabcdef'
>>> tests = ['a', 'abc', 'f', 'ef', 'abcdef']
>>> check_lastindexof(s, tests)
f      FAILED expected: 11, got: 5
ef     FAILED expected: 10, got: 4
abcdef FAILED expected:  6, got: 0

值得注意的是，LastIndexOf returns -1 如果子字符串在字符串中只存在一次，据我所知这显然是错误的：

>>> s = 'abcdef'
>>> check_lastindexof(s, tests)
f      FAILED expected:  5, got: -1
ef     FAILED expected:  4, got: -1
abcdef FAILED expected:  0, got: -1

我是不是误解了 z3.LastIndexOf 应该如何工作，或者某处可能存在错误？

z3-solver 版本：4.8.14.0（通过 pip 安装）

Answer 1

这看起来确实是一个错误。请在 https://github.com/Z3Prover/z3/issues

z3 LastIndexOf returns 错误结果？

z3 LastIndexOf returns wrong result?

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lastindexof

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