Bug 19525 – Duration is not usable with zero-arg std.algorithm.sum

Source: https://stackoverflow.com/questions/53967917/using-std-algorithm-iteration-sum-with-duration import std.algorithm : sum; import std.datetime : Duration, minutes; unittest { // Error: struct `core.time.Duration` member this is not accessible assert([1.minutes].sum() == 1.minutes); } The above code fails because sum() tries to construct Duration(0), which fails to compile. The error message (member this is not accessible) leaves something to be desired. Workaround for now: [1.minutes].sum(Duration.zero). Suggested fix: have sum() check if Seed.zero exists, and use that.

@Zevenberge created dlang/phobos pull request #7339 "Improved error message when calling sum without a default value" mentioning this issue: - Improved error message when calling sum without a default value If sum() is called, it tries to find a default value by constructing it with 0 (e.g. float(0)). This works for numbers, but produces obscure errors if the value cannot be constructed this way (e.g. issue #19525). The error message now states that the problem lies in the default value and suggests to supply one instead. https://github.com/dlang/phobos/pull/7339

dlang/phobos pull request #7339 "Improved error message when calling sum without a default value" was merged into master: - d93e7be91db04889bc5141ccb158c54f77fd2088 by Marco de Wild: Improved error message when calling sum without a default value If sum() is called, it tries to find a default value by constructing it with 0 (e.g. float(0)). This works for numbers, but produces obscure errors if the value cannot be constructed this way (e.g. issue #19525). The error message now states that the problem lies in the default value and suggests to supply one instead. https://github.com/dlang/phobos/pull/7339

Reopened as the issue hasn't been fixed yet. Duration should work out of the box with sum by e.g. checking whether .zero exists or specializing for the duration type.

@Biotronic created dlang/phobos pull request #7504 "Fix issue 19525 - Duration is not usable with zero-arg std.algorithm.sum" fixing this issue: - Fix issue 19525 https://github.com/dlang/phobos/pull/7504

dlang/phobos pull request #7504 "Fix issue 19525 - Duration is not usable with zero-arg std.algorithm.sum" was merged into master: - fd59b6a92e8c2a9e56db0c788f6b40f7d930aef0 by Biotronic: Fix issue 19525 https://github.com/dlang/phobos/pull/7504