https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94767
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to jh718.park from comment #0) > For these variables below, > > unsigned m_schemeEnd : 26; > unsigned m_userStart; > > m_userStart == m_schemeEnd + 1 > > this comparison emits a compiler warning as below. > > warning: comparison of integer expressions of different signedness: > ‘unsigned int’ and ‘int’ [-Wsign-compare] Why do you think that's wrong? In [conv.prom] p5 the standard says: "A prvalue for an integral bit-field (11.4.9) can be converted to a prvalue of type int if int can represent all the values of the bit-field;" Since int is wider than 26 bits it can represent all the values of m_schemeEnd, so the operands of 'm_schemeEnd + 1' are both promoted to int, and the result is an int.
