Review code fixer for CA1861 (Avoid constant arrays)

[mavasani]

The codefix here is quite concerning. Though if there is a problem, it's out of scope for the PR anyway.

If the input code was:

public static List<object> Cases { get; } = new() { new object[0] };

Is there a diagnostic? How the codefix behaves? If the codefix extracted the array to a field below the Cases static property, then it's semantically different.

Originally posted by @Youssef1313 in #6696 (comment)

[buyaa-n]

Thank you @mavasani for fixing NullReferenceException from CA1861

If the input code was:

public static List<object> Cases { get; } = new() { new object[0] };

Is there a diagnostic? How the codefix behaves? If the codefix extracted the array to a field below the Cases static property, then it's semantically different.

Good point, keep warning in this case looks wrong, especially when the array length is not a constant (literal). From the hits found in runtime repo I do not see a valid diagnostic (did not check all), looks most cases it will be false positives, so I am going to put up a PR that exclude these cases.

Let me know if you think there is a valid case, I could not think of any. CC @Youssef1313 @stephentoub

[stephentoub]

If the input code was:
public static List<object> Cases { get; } = new() { new object[0] };

That should trigger the Array.Empty analyzer.

[buyaa-n]

As mentioned in #6714 (comment) Array.Empty analyzer triggered in VS