• via Digitalmars-d-bugs (27/27) Feb 10 2016 https://issues.dlang.org/show_bug.cgi?id=15670

via Digitalmars-d-bugs <digitalmars-d-bugs puremagic.com> writes:

https://issues.dlang.org/show_bug.cgi?id=15670

          Issue ID: 15670
           Summary: std.variant.Variant does not allow classes derived
                    from templated classes
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: phobos
          Assignee: nobody puremagic.com
          Reporter: petar.p.kirov gmail.com

The following code does not compile:

void main()
{
    import std.variant;

    class BaseTemplate(T) { this() {} }
    class Concrete : BaseTemplate!int { this() {} }

    Algebraic!(Concrete) holder;
    Concrete a = new Concrete();
    holder = Algebraic!Concrete(a);
}

Error: static assert  "Cannot store a Concrete in a VariantN!(8LU, Concrete)"
test.d(10):        instantiated from here: __ctor!(Concrete)

--