contract test {
    fn a() ->(u256 n) { return 0; }
    fn b() ->(u256 n) { return 1; }
    fn c() ->(u256 n) { return 2; }
    fn f() ->(u256 n) { return 3; }
}
// ====
// allowNonExistingFunctions: true
// compileToEwasm: also
// compileViaYul: also
// ----
// a()  -> 0
// b()  -> 1
// c()  -> 2
// f()  -> 3
// i_am_not_there()  -> FAILURE