Spread operator in collection read-only property initialization

[Arithmomaniac]

Suppose the type

public class Foo
{
    public IList<int> Bars { get; } = [];
}

Using collection read-only property initialization, we can do this:

var foo = new Foo() 
{ 
    Bars = { 1, 2, 3, 4 }
};

But suppose I don't know which values I want at compile time. Then I would be forced to do as follows:

// int[] bars = ...;
var foo = new Foo();
foreach (var bar in bars)
{
    foo.Bars.Add(bar);
}

I propose that the spread operator be allowed here to do as follows:

// int[] bars = ...;
var foo = new Foo()
{
    Bars = { .. bars, 4 }
};

[colejohnson66]

This could be very useful for ProcessStartInfo.Arguments

[jnm2]

ArgumentList rather? One thing you can do is pass IEnumerable<string> arguments to the ProcessStartInfo constructor.

[TahirAhmadov]

#5354 (comment)

[Arithmomaniac]

That would definitely scratch this itch.

I'm personally partial to reserving [] unambiguously for setting collection properties and {} for filling them. But YMMV.