[over.match.ctor] (original) (raw)
When objects of class type are direct-initialized, copy-initialized from an expression of the same or a derived class type ([dcl.init]), or default-initialized, overload resolution selects the constructor.
For direct-initialization or default-initialization (including default-initialization in the context of copy-list-initialization), the candidate functions are all the constructors of the class of the object being initialized.
Otherwise, the candidate functions are all the non-explicit constructors ([class.conv.ctor]) of that class.
For default-initialization in the context of copy-list-initialization, if an explicit constructor is chosen, the initialization is ill-formed.