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Bug 19637 – Add a pre-condition to "in" and contains()

Status: RESOLVED
Resolution: INVALID
Severity: enhancement
Priority: P1
Component: phobos
Product: D
Version: D2
Platform: All
OS: All
Creation time: 2019-01-31T22:57:52Z
Last change time: 2019-01-31T23:36:50Z
Assigned to: No Owner
Creator: Victor Porton

Comments

Comment #0 by porton — 2019-01-31T22:57:52Z

Accordingly https://dlang.org/phobos/std_range.html "in" and contains() require sorted range. Please add pre-condition to check if it is really sorted. This will help to locate subtle errors.

Comment #1 by sascha.orlov — 2019-01-31T23:29:26Z

Arent't "in" and contains already properties of a SortedRange object? How comes that your SortedRange is not sorted? According to https://dlang.org/phobos/std_algorithm_sorting.html#.isSorted the check for sortedness would require O(r.length) evaluations. I don't think, you really want to have this check run every evaluation of "in" or contains, do you?

Comment #2 by porton — 2019-01-31T23:36:50Z

I have not noticed that contains() is a member of SortedRange. So, you are right, I am closing the bug.