Annex C (informative) Compatibility [diff]

C.3 C++ and ISO C++ 2011 [diff.cpp11]

C.3.4 Clause [dcl.dcl]: declarations [diff.cpp11.dcl.dcl]

Change: constexpr non-static member functions are not implicitly const member functions.
Rationale: Necessary to allow constexpr member functions to mutate the object.
Effect on original feature: Valid C++ 2011 code may fail to compile in this International Standard. For example, the following code is valid in C++ 2011 but invalid in this International Standard because it declares the same member function twice with different return types:

struct S {
  constexpr const int &f();
  int &f();