Why doesn't use an invalid name in discards？

[CreateAndInject]

As we know, "_" is a valid name:

if (int.TryParse("123", out int a))
    Console.WriteLine(a);

if (int.TryParse("123", out int _))
    Console.WriteLine(_);

So, I think these 2 are both correct.

Why doesn't use an invalid name (such as * or #) instead of _?
like this:

if (int.TryParse("123", out int *))
{
//this time, nobody will try to use:
//Console.WriteLine(*);
}

[svick]

This is documented in Language Design Meeting notes for 15 November 2016 (emphasis mine):

We got great feedback on "wildcards" at the MVP Summit, including changing its name to the term "discards", which is spreading in industry.

We are also encouraged to use _ as the discard character instead of *. It works better visually, and is what many other languages already use.

[HaloFour]

@CreateAndInject

This was a subject of a lot of debate and I still don't agree with the outcome, but that's where we are now.

#14794
#14832
#14862
dotnet/csharplang#1064

[sharwell]

@CreateAndInject I believe the answers to your question(s) can be found in the links provided by @HaloFour. If you have additional questions, you can ask them in dotnot/csharplang. 😄