C#C
C#•13mo ago
seky16

records, with expression, required property

I'm hitting a strange behaviour and not sure if it's intended.
I have the following record definition:
public record Options
{
    public required IDataSource DataSource { get; init; }

    public int? Take { get; init; } = null;
}

Then I use it in code like this:
var config = new Options() { DataSource = new DataSource(), }
assert(config.DataSource is null) // false
var config2 = config with { Take = null };
assert(config2.DataSource is null); // true
var config3 = config with { Take = null, DataSource = config.DataSource };
assert(config3.DataSource is null); // false

Why is config2.DataSource null? Is this intended behaviour of combining required and 
with
?
If so, shouldn't I get a warning/error that I have an uninitialised required property in config2?
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