Implement PROBLEMATIC_CONSTS generalization

[donno2048]

You forgot that A≈4, B≈8, and E≈3 and some more constants.

The new PROBLEMATIC_CONSTS was generated using this code:

from functools import reduce
def generate_problems(consts: list, letter_digit: dict):
    for const in consts:
        problem = reduce(lambda string, rep: string.replace(*reversed(rep)), ['%X' % const, *letter_digit.items()])
        indexes = [index for index, c in enumerate(problem) if c in letter_digit.keys()]
        for i in range(1 << len(indexes)):
            yield int(''.join(letter_digit[c] if index in indexes and (i >> indexes.index(index)) & 1 else c for index, c in enumerate(problem)), 0x10)


problems = generate_problems(
    [
        # Old PROBLEMATIC_CONSTS:
        184594741, 2880289470, 2881141438, 2965027518, 2976579765, 3203381950, 3405691582, 3405697037,
        3735927486, 3735932941, 4027431614, 4276992702,
        # More of my own:
        195934910, 252707358, 762133, 179681982, 173390526
    ],
    {
    'A': '4',
    'B': '8',
    'E': '3',
    }
)

# print(list(problems)) # won't use that to print formatted

from itertools import islice
while len(cur_problems := list(islice(problems, 8))):
    print('    ', end='')
    print(*cur_problems, sep=', ', end='')
    print(',')

[rustbot]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @Mark-Simulacrum (or someone else) soon.

Please see the contribution instructions for more information. Namely, in order to ensure the minimum review times lag, PR authors and assigned reviewers should ensure that the review label (S-waiting-on-review and S-waiting-on-author) stays updated, invoking these commands when appropriate:

• @rustbot author: the review is finished, PR author should check the comments and take action accordingly
• @rustbot review: the author is ready for a review, this PR will be queued again in the reviewer's queue

[dtolnay]

Thanks!

Would it be possible to keep just the short list of root problematic consts, and then put your generate_problems logic into tidy, instead of expanding it all out like this?

That would be much more easily auditable.

[donno2048]

@dtolnay I thought because the list is static it'd be better to make it hardcoded, wouldn't it?

[dtolnay]

I don't know a reason that it would need to be static.

[donno2048]

But also correct me if I'm wrong, but without using the generate_problems function the (PROBLEMATIC_CONSTS.iter().map(u32::to_string)) won't work as expected

[dtolnay]

Yes, good point. The regex approach (.replace("a", "[aA4]") etc.) results in not finding capitalization variations for values that are problematic in hex but written as decimal in the source code.

I don't know the importance of looking for the decimal converted values.

I have assigned back to @joshtriplett who created this lint originally.

[donno2048]

I think if we are ignoring some cases of (PROBLEMATIC_CONSTS.iter().map(u32::to_string)) we should remove it completely

[donno2048]

@rustbot review

[albertlarsan68]

LGTM, thanks for the PR!

[albertlarsan68]

@bors r+

[bors]

📌 Commit e2ab540 has been approved by albertlarsan68

It is now in the queue for this repository.

[bors]

⌛ Testing commit e2ab540 with merge 43a0686...

[bors]

☀️ Test successful - checks-actions
Approved by: albertlarsan68
Pushing 43a0686 to master...

[rust-timer]

Finished benchmarking commit (43a0686): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.2%, 0.2%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[0.2%, 0.2%]	2

Max RSS (memory usage)

This benchmark run did not return any relevant results for this metric.

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 671.432s -> 673.234s (0.27%)
Artifact size: 315.27 MiB -> 315.21 MiB (-0.02%)