Building article_number.o on Mac
Making all in general
CXX article_number.o
In file included from article_number.cc:3:
../../pan/general/string-view.h:89:32: warning: 'constexpr' non-static member function will not be implicitly 'const' in C++14; add 'const' to avoid a change in
behavior [-Wconstexpr-not-const]
constexpr StringView& operator=(StringView const &) = default;
^
const
../../pan/general/string-view.h:89:32: error: an explicitly-defaulted copy assignment operator may not have 'const', 'constexpr' or 'volatile' qualifiers
1 warning and 1 error generated.
Removing 'constexpr' from line 89 of pan/general/string-view.h seems to fix the problem.