[Issue 19885] possibility to skip required initialization in constructor using ref parameter

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19885

RazvanN <razvan.nitu1305 at gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |razvan.nitu1305 at gmail.com

--- Comment #1 from RazvanN <razvan.nitu1305 at gmail.com> ---
I think that the behavior was designed to allow for:

initializeA(ref A a)
{
    a = A(2);
}

struct B
{
    A a;
    this(int)
    {
        initializeA(a);
    }
}

This is a common pattern and forbidding this might brake a lot of code.
However, there is no way the compiler can know if the function actually
initializes a or not.

The problem with `out` is slightly different. Since A does not have default
construction the parameter cannot be initialized before entering the function.

Also, there is this issue [1], which was fixed by considering that taking the
address of a variable in the constructor is the same as initializing it.
Passing a field by ref to a function could be seen the same as taking its
address, so by those standards this issue would be a WONTFIX. 

[1] https://issues.dlang.org/show_bug.cgi?id=15869

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