Bug#1132062: amoebax: ftbfs with GCC-16

[Simon McVittie]

On Fri, 27 Mar 2026 at 18:18:03 +0100, Emanuele Rocca wrote:
>The full build log can be found at:
>https://people.debian.org/~ema/gcc-16-rebuilds/output-1/amoebax_arm64.build.xz
>
>The last lines of the build log are at the end of this report.

Unfortunately they didn't contain the error, which appears to be:

/usr/include/c++/16/bits/stl_numeric.h: In instantiation of ‘constexpr _Tp std::accumulate(_InputIterator, _InputIterator, _Tp, _BinaryOperation) [with _InputIterator = __gnu_cxx::__normal_iterator<const char*, __cxx11::basic_string<char> >; _Tp = short unsigned int; _BinaryOperation = Amoebax::Font::TextWidth]’:
Font.cxx:71:28:   required from here
    71 |     return std::accumulate (text.begin (), text.end (),
       |            ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
    72 |                             static_cast<uint16_t>(0), TextWidth (this));
       |                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/16/bits/stl_numeric.h:169:29: error: no match for call to ‘(Amoebax::Font::TextWidth) (std::remove_reference<short unsigned int&>::type, const char&)’
   169 |         __init = __binary_op(_GLIBCXX_MOVE_IF_20(__init), *__first);
       |                  ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   • there is 1 candidate
     Font.h:67:20:
        67 |             struct TextWidth:
           |                    ^~~~~~~~~
     • candidate 1: ‘uint16_t Amoebax::Font::TextWidth::operator()(uint16_t&, const char&)’ (near match)
       Font.h:98:17:
          98 |                 operator() (uint16_t &widthSoFar, const char &currentCharacter)
             |                 ^~~~~~~~
       • conversion of argument 1 would be ill-formed:
       • error: cannot bind non-const lvalue reference of type ‘uint16_t&’ {aka ‘short unsigned int&’} to an rvalue of type ‘std::remove_reference<short unsigned int&>::type’ {aka ‘short unsigned int’}

(Someone who is better at C++ than me will have to solve this, sorry)

     smcv