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/// 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 /// /// ```rust /// # #[macro_use] extern crate claim; /// # use std::task::Poll; /// # fn main() { /// 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: /// /// ```rust /// # #[macro_use] extern crate claim; /// # use std::task::Poll; /// # fn main() { /// let res: Poll<i32> = Poll::Pending; /// /// let value = assert_pending!(res); /// assert_eq!(value, Poll::Pending); /// # } /// ``` /// /// [`Poll::Ready(T)`] variant will cause panic: /// /// ```rust,should_panic /// # #[macro_use] extern crate claim; /// # use std::task::Poll; /// # fn main() { /// let res = Poll::Ready(42); /// /// assert_pending!(res); // Will panic /// # } /// ``` /// /// [`Poll::Ready(T)`]: https://doc.rust-lang.org/core/task/enum.Poll.html#variant.Ready /// [`Poll::Pending`]: https://doc.rust-lang.org/core/task/enum.Poll.html#variant.Pending /// [`std::fmt`]: https://doc.rust-lang.org/std/fmt/index.html /// [`debug_assert_pending!`]: ./macro.debug_assert_pending.html #[macro_export] macro_rules! assert_pending { ($cond:expr,) => { $crate::assert_pending!($cond); }; ($cond:expr) => { match $cond { p @ core::task::Poll::Pending => p, r @ core::task::Poll::Ready(..) => { panic!("assertion failed, expected Pending, got {:?}", r); } } }; ($cond:expr, $($arg:tt)+) => { match $cond { p @ core::task::Poll::Pending => p, r @ core::task::Poll::Ready(..) => { panic!("assertion failed, expected Pending, got {:?}", format_args!($($arg)+)); } } }; } /// Asserts that expression returns [`Poll::Pending`] variant in runtime. /// /// This macro is available for Rust 1.36+. /// /// Like [`assert_pending!`], this macro also has a second version, /// where a custom panic message can be provided. /// /// ## Uses /// /// See [`debug_assert!`] documentation for possible use cases. /// The same applies to this macro. /// /// [`Poll::Pending`]: https://doc.rust-lang.org/core/task/enum.Poll.html#variant.Pending /// [`debug_assert!`]: https://doc.rust-lang.org/std/macro.debug_assert.html /// [`assert_pending!`]: ./macro.assert_pending.html #[macro_export] macro_rules! debug_assert_pending { ($($arg:tt)*) => (if core::cfg!(debug_assertions) { $crate::assert_pending!($($arg)*); }) }