[−][src]Macro claim::assert_pending
Asserts that expression returns Poll::Pending
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_pending!
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<i32> = Poll::Pending; assert_pending!(res); // With custom messages assert_pending!(res, "Future is not ready yet");
Poll::Pending
variant will also be returned from this macro call:
let res: Poll<i32> = Poll::Pending; let value = assert_pending!(res); assert_eq!(value, Poll::Pending);
Poll::Ready(T)
variant will cause panic:
let res = Poll::Ready(42); assert_pending!(res); // Will panic