[API Proposal]: Collection Expressions and String.Empty

[TonyValenti]

Background and motivation

It would be really convenient if [] could be used as a shorthand for String.Empty.

API Proposal

I am not sure what is necessary to make this possible.

API Usage

public record Person {
  public string Name { get; init; } = [];
}

Alternative Designs

We could leave it as-is.
Also, someone could just use "" but that isn't as nice as [].

Risks

No response

[alrz]

If anything, wouldn't it make sense to emit "" as string.empty?

That's assuming that this has any advantage over it (on that, there's #8300)

[julealgon]

It would be really convenient if [] could be used as a shorthand for String.Empty.

How so?

Also, someone could just use "" but that isn't as nice as [].

Why? How are you defining "niceness" here?

[KennethHoff]

I find "" undesirable because I can never truly know if it's empty or if it contains zero-width characters (unless you're using a reader that makes that clear, which I don't know if GitHub does)

[HaloFour]

That seems a bit extreme, and if you're really trying to guard against that then string.Empty should be sufficient.

I'm not opposed to [] being considered an empty string, but not on it's own. I don't think that's worth doing without allowing collection literals to be used to create strings in general, e.g. string foo = [ 'h', 'e', 'l', 'l', 'o' ];.

[KennethHoff]

That seems a bit extreme, and if you're really trying to guard against that then string.Empty should be sufficient.

I do exclusively use string.Empty already :)

[jnm2]

I'd suggest an analyzer that shows warning or info squiggles for strings that could be confused with the empty string. The problem wouldn't be limited just to the empty string literal, either.

[colejohnson66]

Honestly, an analyzer that flags any non-visible or formatting Unicode codepoints would be nice. If I need a non-breaking space or zero-width joiner, I define it as a constant and use it with interpolation:

private const char NBSP = '\xA0';
private const char ZWJ = '\x200D';
public const string SomeString = $"Start{NBSP}Middle{ZWJ}End";