missing panic on overflow !? about rust-decimal HOT 6 CLOSED

Agreed. Will look into this one. Thanks for the example!

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So there is definitely an underflow happening with addition whereby the last bit exceeds the allocated 96 bit storage space at that scale. While I could panic, I feel like this should rather work and instead round to 8314.622985886882835357072470.

If I did this and instead provided checked functions would this help your case?

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Looking at some other libraries output it appears that rounding (or losing precision) in this case is the de facto. For consistency I think this is what I'll implement however do want to consider functions and cases whereby this loss of precision is unacceptable.

from rust-decimal.

rounding the last decimal places and loosing a tiny bit of precision sounds like a good solution for cases like this.

i can imagine there are users that don't want to silently loose even a tiny bit of precision and would like to know when overflow/rounding occurs. the checked functions sound like a good solution.

how do we ensure that there are no further cases like this, where an overflow silently results in completely wrong results? you describe the crate as suitable for financial calculations. in financial applications errors like this could have pretty bad consequences.

i'd have more confidence in the crate if it tested common math invariants using something like https://github.com/BurntSushi/quickcheck. happy to add some quickcheck tests if you agree.

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QuickCheck looks interesting - I'd be happy to get this included. How would you intend on utilizing it?

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I'm going to pull implementing QuickCheck into a new issue so I can close this one once it's fixed.

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