@`+`: (int, int) -> int;
@`+`: (num, num) -> num;
@`-`: (int, int) -> int;
@`-`: (num, num) -> num;
@`/`: (int, int) -> int;
@`/`: (num, num) -> num;
@`*`: (int, int) -> int;
@`*`: (num, num) -> num;
@`&&`: (bool, bool) -> bool;
@`||`: (bool, bool) -> bool;
@`+`: (Vec[#M, T], Vec[#M, T]) -> Vec[#M, T];
@as__character: (Any) -> char;
@source: (char) -> Empty;
@reduce: ([#N, T], (T, U) -> T) -> T;
@sum: ([#N, T]) -> T;
@test_that: (char, Any) -> Empty;
@expect_true: (bool) -> Empty;
@expect_false: (T, T) -> Empty;
@expect_equal: (T, T) -> Empty;