Add loop invariants and harnesses for DecimalSeq functions #439
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tautschnig
reviewed
Aug 1, 2025
| let mut a: DecimalSeq = kani::any(); | ||
| let shift: usize = kani::any_where(|x| *x > 0 && *x <= 60); | ||
| let n = number_of_digits_decimal_left_shift(&a, shift); | ||
| assert!(n <= 19); |
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Can you explain the magic number "19" (and include a comment doing so)?
tautschnig
reviewed
Aug 4, 2025
| @@ -363,6 +381,7 @@ fn number_of_digits_decimal_left_shift(d: &DecimalSeq, mut shift: usize) -> usiz | |||
| let pow5_b = (0x7FF & x_b) as usize; | |||
| let pow5 = &TABLE_POW5[pow5_a..]; | |||
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| #[kani::loop_invariant(true)] | |||
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This currently fails with error: custom attribute panicked - presumably because we need a Kani version that has for loop support merged?
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Yes, I mentioned it in the PR description.
| impl kani::Arbitrary for DecimalSeq { | ||
| fn any() -> DecimalSeq { | ||
| let mut ret = DecimalSeq { | ||
| num_digits: kani::any(), |
Co-authored-by: Michael Tautschnig <[email protected]>
Co-authored-by: Michael Tautschnig <[email protected]>
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This PR adds loop invariants and harnesses for DecimalSeq functions
Require: for-loop support for Kani: model-checking/kani#4143
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.