Annex C (informative) Compatibility [diff]

C.4 C++ and ISO C++ 2014 [diff.cpp14]

C.4.5 [class]: classes [diff.cpp14.class]

Affected subclause: [class.inhctor.init]
Change: Inheriting a constructor no longer injects a constructor into the derived class.

Rationale: Better interaction with other language features.

Effect on original feature: Valid C++ 2014 code that uses inheriting constructors may not be valid or may have different semantics.
A using-declaration that names a constructor now makes the corresponding base class constructors visible to initializations of the derived class rather than declaring additional derived class constructors.
For example: struct A { template<typename T> A(T, typename T::type = 0); A(int); }; struct B : A { using A::A; B(int); }; B b(42L); // now calls B(int), used to call B<long>(long), // which called A(int) due to substitution failure // in A<long>(long).