Function patch_seq_socket_cast 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn patch_seq_socket_cast(stack: Stack) -> Stack

Cast between Socket and Int (both directions): identity at runtime.

Socket is a compile-time-only nominal wrapper over the same i64 file descriptor; the type checker enforces the distinction. This shim exists so codegen can emit a callable symbol for fd->socket / socket->fd without inventing a new value tag.

Safety

Stack must have an Int (or Socket-shaped Int) value on top.