Improve struct constructor to make it work like class constructor

[KorneiDontsov]

When I use struct and wrote parameterized constructor, I must initialize every field with a value, even if it is going to be default.

struct MyStruct {
    public readonly Object required;

    public Object? optional;

    public MyStruct(Object required) {
        this.requred = required;
        optional = null;
    }
}

But in class I doesn't have to do it. Field is default/null by default.

It's annoying that in struct I have to wrote even more code than in class in order to do exactly same thing. I propose to make the compiler do the work even if implementation of how struct constructor works is different from how class constructor works.

Examples

struct MyStruct {
    public readonly Object required;

    public Object? optional;

    public MyStruct(Object required) {
        this.requred = required;
        // Compiler understands that 'optional' is not initialized
        // and initializes it here with null.
    }
}

struct MyStruct {
    public readonly Object required;

    public Object? optional;

    public MyStruct(Object required) {
        this.requred = required;
        // Compiler understands that 'optional' is going to be used without being initialized 
        // and initializes it here with null.
        Console.WriteLine(optional);
        // or
        Console.WriteLine(this);
    }
}

[SingleAccretion]

Note that there is a workaround for this limitation:

public struct Struct
{
    public int Int;    
    public double Double;
    public string String;
    
    public Struct(int integer)
    {
        this = default;
        Int = integer;
    }        
}

It is a bit ugly, but it does save on typing.

[svick]

Another workaround, arguably one that is less ugly, is to explicitly delegate to this():

struct S
{
    public int Int;    
    public double Double;
    public string String;
    
    public S(int integer) : this()
    {
        Int = integer;
    }        
}