//blah1.d

class A
{
    private this(){}
}


//blah2.d

import blah1;

class B : A {}


$ dmd blah1.d blah2.d -lib
Error: constructor blah1.A.this is not accessible from module blah2

Can someone explain why this can't/doesn't work? Thanks.

On Tuesday, 29 April 2014 at 13:59:30 UTC, John Colvin wrote:
> //blah1.d
>
> class A
> {
>     private this(){}
> }
>
>
> //blah2.d
>
> import blah1;
>
> class B : A {}
>
>
> $ dmd blah1.d blah2.d -lib
> Error: constructor blah1.A.this is not accessible from module blah2
>
> Can someone explain why this can't/doesn't work? Thanks.

Also, I noticed that adding a blank constructor ( this(){} ) to B didn't help, but adding a blank template constructor ( this()(){} ) makes the error go away.

http://dlang.org/class.html#constructors

"If no call to constructors via this or super appear in a constructor, and the base class has a constructor, a call to super() is inserted at the beginning of the constructor."

The fact that call to base constructor is not inserted into templated this()() looks like a bug to me.

On 4/29/14, Dicebot via Digitalmars-d-learn <digitalmars-d-learn@puremagic.com> wrote:
> The fact that call to base constructor is not inserted into
> templated this()() looks like a bug to me.

Just found this, and it might be related: https://issues.dlang.org/show_bug.cgi?id=5770

On Tue, 29 Apr 2014 13:59:28 +0000
John Colvin via Digitalmars-d-learn <digitalmars-d-learn@puremagic.com>
wrote:
> Can someone explain why this can't/doesn't work? Thanks.
hm. why it should? there is no 'default' constructors in D, and you specifially made explicit one private (i.e. not visible outside the module). and adding constructor to B inherits 'private' (not sure if it is right though). but templated one generates constructor code 'on demand', w/o 'private'.

i think that public constructor in B should work, so this may be bug. will wait for somebody more expirienced in language to jump in before filling bug report though.

On Tuesday, 29 April 2014 at 18:51:15 UTC, ketmar via Digitalmars-d-learn wrote:
> On Tue, 29 Apr 2014 13:59:28 +0000
> John Colvin via Digitalmars-d-learn <digitalmars-d-learn@puremagic.com>
> wrote:
>> Can someone explain why this can't/doesn't work? Thanks.
> hm. why it should? there is no 'default' constructors in D, and you
> specifially made explicit one private (i.e. not visible outside the
> module). and adding constructor to B inherits 'private' (not sure if it
> is right though). but templated one generates constructor code 'on
> demand', w/o 'private'.
>
> i think that public constructor in B should work, so this may be bug.
> will wait for somebody more expirienced in language to jump in before
> filling bug report though.

No it shouldn't. Private != protected. If A constructor is private, no one outside of same module can access it, not even B which is direct descendant.