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/// Asserts that expression matches any of the given variants. /// /// This macro is available for Rust 1.32+. /// /// It works exactly as [`std::matches!`] macro, /// except it panics if there is no match. /// /// ## Uses /// /// Assertions are always checked in both debug and release builds, and cannot be disabled. /// See [`debug_assert_matches!`] 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; /// # fn main() { /// let foo = 'f'; /// assert_matches!(foo, 'A'..='Z' | 'a'..='z'); /// /// // With custom messages /// assert_matches!(foo, 'A'..='Z' | 'a'..='z', "expecting it to be letter: {}", foo); /// # } /// ``` /// /// ```rust,should_panic /// # #[macro_use] extern crate claim; /// # fn main() { /// let bar: Option<i32> = None; /// assert_matches!(bar, Some(x) if x > 2); // Will panic /// # } /// ``` /// /// [`std::matches!`]: https://doc.rust-lang.org/stable/std/macro.matches.html /// [`std::fmt`]: https://doc.rust-lang.org/std/fmt/index.html /// [`debug_assert_matches!`]: ./macro.debug_assert_matches.html #[macro_export] macro_rules! assert_matches { ($expression:expr, $( $pattern:pat )|+ $( if $guard: expr )?) => { match $expression { $( $pattern )|+ $( if $guard )? => {}, other => { panic!(r#"assertion failed, expression does not match any of the given variants. expression: {:?} variants: {}"#, other, stringify!($($pattern) |+ $(if $guard)?)); } } }; ($expression:expr, $( $pattern:pat )|+ $( if $guard: expr )?, $($arg:tt)+) => { match $expression { $( $pattern )|+ $( if $guard )? => {}, other => { panic!(r#"assertion failed, expression does not match any of the given variants. expression: {:?} variants: {}: {}"#, other, stringify!($($pattern) |+ $(if $guard)?), format_args!($($arg)+)); } } }; } /// Asserts that expression matches any of the given variants. /// /// Like [`assert_matches!`], this macro also has a second version, /// where a custom panic message can be provided. /// /// ## Uses /// /// See [`debug_assert_matches!`] documentation for possible use cases. /// The same applies to this macro. /// /// [`Err(E)`]: https://doc.rust-lang.org/core/result/enum.Result.html#variant.Err /// [`debug_assert!`]: https://doc.rust-lang.org/std/macro.debug_assert.html /// [`assert_matches!`]: ./macro.assert_matches.html #[macro_export] macro_rules! debug_assert_matches { ($($arg:tt)*) => (if cfg!(debug_assertions) { $crate::assert_matches!($($arg)*); }) }