VSTHRD200 should be able to have method type configured

[jamiehankins]

Is your feature request related to a problem? Please describe.

This analyzer reports all instances of this condition. There are different schools of thought about requiring an Async suffix on awaitable methods.

• Always, all the time (or not at all) -- these are the only current options
• Only on public methods
• Only on methods that also have non-awaitable methods
• Only on non-private methods (my preference)
• Combinations of the above

Describe the solution you'd like

I'd like to see .editorconfig settings to modify the behavior of this analyzer.
dotnet_diagnostic.VSTHRD200.allowed_exceptions = private, internal, protected, no_non_async

Whether it takes this exact form doesn't matter. I just want to shut this warning up for private methods.

Describe alternatives you've considered

I can silence all instances of this analyzer, silence it by file, live with warnings, or follow rules that we don't agree with.

Additional context

I use source generators for binding methods to a view, and the "fix" functionality renames methods but not the generated reference to them in XAML. So this:

private async Task AddStation() { }

which is generated as

public global::CommunityToolkit.Mvvm.Input.IRelayCommand DeleteUserCommand => deleteUserCommand ??= new global::CommunityToolkit.Mvvm.Input.RelayCommand(new global::System.Action(DeleteUser), () => CanDeleteUser);

would be DeleteUserAsyncCommand, and I would have to go through all of my XAML views and fix it.

[AArnott]

Thanks for this thoughtful write-up. I'd add "local functions" to your list of possible variants. At the moment, I think VSTHRD200 ignores them, and I'm content with that policy.

As for the rest of the variations you propose, it adds complexity, and that would need to be accompanied by additional automated testing.
I don't see Visual Studio funding this in the forseeable future, but if you're interested in contributing this feature with tests, I could see us merging it. If you want to take this on, we can iterate on the .editorconfig syntax.

We should also consider #1315.