fix(strconv): adjust the logic for validating base

[Yu-zh]

No description provided.

[peter-jerry-ye-code-review]

Prefix handling logic change may affect backward compatibility

Category
Correctness
Code Snippet
['0', 'x' | 'X', .. rest] if base == 16 => (16, rest, true)
Recommendation
Consider adding a comment explaining the behavior change where '0b01' with base=16 is now valid and parsed as 2817
Reasoning
The new behavior where prefix is treated as part of the number when base doesn't match might be surprising. This should be clearly documented as it appears to be an intentional change based on the new test cases.

Test cases could be better organized

Category
Maintainability
Code Snippet
test "more edge cases" { ... }
Recommendation
Split the test cases into logical groups with descriptive names like 'test_prefix_with_matching_base' and 'test_prefix_with_non_matching_base'
Reasoning
The current test organization makes it harder to understand what specific behaviors are being tested. Grouping related test cases would improve readability and maintenance.

Base range check should be moved earlier

Category
Correctness
Code Snippet
_ => if base is (1..=36) { (base, view, false) } else { base_err!() }
Recommendation
Move the base range check to the start of the function to fail fast:

fn check_and_consume_base(...) {
  if base != 0 && !(base is (1..=36)) { base_err!() }
  // rest of the function
}
**Reasoning**
Validating the base parameter early makes the function more robust and easier to reason about. Currently, the base range check only happens in one code path.

</details>

[coveralls]

Pull Request Test Coverage Report for Build 6461

Details

• 11 of 11 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.01%) to 92.682%

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Totals
Change from base Build 6455:	0.01%
Covered Lines:	6117
Relevant Lines:	6600

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💛 - Coveralls