Unexpected result for string.IndexOf((char)0, StringComparison.InvariantCultureIgnoreCase)

[KlestovAlexej]

C# .NET 7

// 0
Console.WriteLine("qwerty".IndexOf((char)0, StringComparison.InvariantCultureIgnoreCase));

// -1
Console.WriteLine("qwerty".IndexOf((char)0));

// -1
Console.WriteLine("qwerty".IndexOf('z'));

// -1
Console.WriteLine("qwerty".IndexOf('z', StringComparison.InvariantCultureIgnoreCase));

[ghost]

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Issue Details

---

C# .NET 7

// 0
Console.WriteLine("qwerty".IndexOf((char)0, StringComparison.InvariantCultureIgnoreCase));

// -1
Console.WriteLine("qwerty".IndexOf((char)0));

// -1
Console.WriteLine("qwerty".IndexOf('z'));

// -1
Console.WriteLine("qwerty".IndexOf('z', StringComparison.InvariantCultureIgnoreCase));

Author:	KlestovAlexej
Assignees:	-
Labels:	area-System.Globalization
Milestone:	-

[huoyaoyuan]

See #46569, #47145, #54951 and so on.

[huoyaoyuan]

Should we link to some description of this behavior in the documentation of string.IndexOf? Currently I'm not seeing any.

[tarekgh]

@huoyaoyuan we have doc at https://learn.microsoft.com/en-us/dotnet/core/extensions/globalization-icu#stringindexof for this behavior but I think it will be a good idea add something to IndexOf. Are you interested in submitting PR for it?