C++
clang HEAD 12.0.0 (https://github.com/llvm/llvm-project.git 9087209314caafed4b232d4a66287f2d16054ad3)
$ clang++ prog.cc -Wall -Wextra -I/opt/wandbox/boost-1.73.0/clang-head/include -std=c++2a -Weverythingprog.cc:19:4: warning: expression result unused [-Wunused-value]
a;
^
prog.cc:17:3: warning: no previous prototype for function 'operator,' [-Wmissing-prototypes]
B operator , (A a, B b)
^
prog.cc:17:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
B operator , (A a, B b)
^
static
prog.cc:30:4: warning: expression result unused [-Wunused-value]
a, s; // C4913 uses builtin comma operator
^
prog.cc:30:5: warning: possible misuse of comma operator here [-Wcomma]
a, s; // C4913 uses builtin comma operator
^
prog.cc:30:4: note: cast expression to void to silence warning
a, s; // C4913 uses builtin comma operator
^
static_cast<void>( )
prog.cc:30:7: warning: expression result unused [-Wunused-value]
a, s; // C4913 uses builtin comma operator
^
prog.cc:32:2: warning: C++98 requires newline at end of file [-Wc++98-compat-pedantic]
}
^
6 warnings generated.