Warning: possible misuse of comma operator here

[dan-ryan]

While compiling my code on XCode, I get this warning.

sole.hpp:724:12: warning: possible misuse of comma operator here [-Wcomma]
                u.ab = ab, u.cd = cd;
                         ^
sole.hpp:724:3: note: cast expression to void to silence warning
                u.ab = ab, u.cd = cd;
                ^~~~~~~~~
                static_cast<void>( )
1 warning generated.

[r-lyeh]

ty!