[Core] LastIndexOf{T} method in EnumerableExtensions.cs has invalid implementation for IList{T} branch.

[discosultan]

Hello!

I'll just post the failing code snippet. Should be self explanatory ;)

        var range1 = new Stack<int>(); range1.Push(1); // This will hit the IEnumerable branch of LastIndexOf method.
        var range2 = new[] { 1 }; // This will hit the IList branch of LastIndexOf method.

        Console.WriteLine(range1.IndexOf(x => x == 1)); // 0
        Console.WriteLine(range2.IndexOf(x => x == 1)); // 0
        Console.WriteLine(range1.LastIndexOf(x => x == 1)); // 0
        Console.WriteLine(range2.LastIndexOf(x => x == 1)); // -1 Incorrect!

[gitfool]

You can link to the source now; EnumerableExtensions.cs:86 should use i >= 0.

[discosultan]

Thanks for the tip about source code linkage.

[gitfool]

You're welcome. That's a nice obvious fix, so the next step would've been to fork the repo and submit a pull request. ;)

[discosultan]

This seemed like a small enough fix that I couldn't bother with a pull request.

I didn't notice at first, but actually the implementation for the IEnumerable branch is also broken and will return the first index instead of the last one.

EnumerableExtensions.cs#L93-L100

[Benlitz]

Looks like you're right :) This method will be fixed in the next release, sorry for that

[discosultan]

Np! I'm glad if I can be of any help.