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 prog.cc:5:6: warning: expression result unused [-Wunused-value]
i + j; // C4552
~ ^ ~
prog.cc:5:4: warning: variable 'i' is uninitialized when used here [-Wuninitialized]
i + j; // C4552
^
prog.cc:4:9: note: initialize the variable 'i' to silence this warning
int i, j;
^
= 0
prog.cc:5:8: warning: variable 'j' is uninitialized when used here [-Wuninitialized]
i + j; // C4552
^
prog.cc:4:12: note: initialize the variable 'j' to silence this warning
int i, j;
^
= 0
3 warnings generated.