Inherit and overload default constructor

Question

I\'ve been searching for this and I\'m amazed I haven\'t found anything. Why can\'t I inherit a base class constructor using using declaration and add an overlo

Answer 1

The problem is that default-constructors are not inherited. From [class.inhctor]/p3:

For each non-template constructor in the candidate set of inherited constructors [..], a constructor is implicitly declared with the same constructor characteristics unless there is a user-declared constructor with the same signature in the complete class where the using-declaration appears or the constructor would be a default, copy, or move constructor for that class.

You also have a user-declared constructor that suppresses the creation of an implicit default-constructor. Just add a defaulted one to make it work:

B() = default;