Macro claim::assert_ready_ok

macro_rules! assert_ready_ok {
    ($cond:expr,) => { ... };
    ($cond:expr) => { ... };
    ($cond:expr, $($arg:tt)+) => { ... };
}

Asserts that expression returns Poll::Ready(Ok(T)) variant.

This macro is available for Rust 1.36+.

Uses

Assertions are always checked in both debug and release builds, and cannot be disabled. See debug_assert_ready_ok! for assertions that are not enabled in release builds by default.

Custom messages

This macro has a second form, where a custom panic message can be provided with or without arguments for formatting. See std::fmt for syntax for this form.

Examples

let res: Poll<Result<i32, ()>> = Poll::Ready(Ok(42));

assert_ready_ok!(res);

Value of T type from the Poll::Ready(Ok(T)) will also be returned from this macro call:

let res: Poll<Result<i32, ()>> = Poll::Ready(Ok(42));

let value = assert_ready_ok!(res);
assert_eq!(value, 42);

Both Poll::Ready(Err(..)) and Poll::Pending variants will cause panic:

let res: Poll<Result<i32, ()>> = Poll::Ready(Err(()));

assert_ready_ok!(res);  // Will panic

let res: Poll<Result<i32, ()>> = Poll::Pending;

assert_ready_ok!(res);  // Will panic