Nim (the original one, not Nimony) compiles to C, so making basic types work differently from C would involve major performance costs.

Presumably unsigned want to return errors too?

Edit: I guess they could get rid of a few numbers... Anyhow it isn't a philosophy that is going to get me to consider nimony for anything.

> making basic types work differently from C would involve major performance costs.

Not if you compile with optimizations on. This C code:

  int wrapping_add_ints(int x, int y) {
      return (int)((unsigned)x + (unsigned)y);
  }

  wrapping_add_ints:
          lea     eax, [rdi + rsi]
          ret