diff options
Diffstat (limited to '')
| -rw-r--r-- | library/core/src/bool.rs | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/library/core/src/bool.rs b/library/core/src/bool.rs index 7667a6508..db1c505ba 100644 --- a/library/core/src/bool.rs +++ b/library/core/src/bool.rs @@ -18,6 +18,18 @@ impl bool { /// assert_eq!(false.then_some(0), None); /// assert_eq!(true.then_some(0), Some(0)); /// ``` + /// + /// ``` + /// let mut a = 0; + /// let mut function_with_side_effects = || { a += 1; }; + /// + /// true.then_some(function_with_side_effects()); + /// false.then_some(function_with_side_effects()); + /// + /// // `a` is incremented twice because the value passed to `then_some` is + /// // evaluated eagerly. + /// assert_eq!(a, 2); + /// ``` #[stable(feature = "bool_to_option", since = "1.62.0")] #[rustc_const_unstable(feature = "const_bool_to_option", issue = "91917")] #[inline] @@ -37,6 +49,17 @@ impl bool { /// assert_eq!(false.then(|| 0), None); /// assert_eq!(true.then(|| 0), Some(0)); /// ``` + /// + /// ``` + /// let mut a = 0; + /// + /// true.then(|| { a += 1; }); + /// false.then(|| { a += 1; }); + /// + /// // `a` is incremented once because the closure is evaluated lazily by + /// // `then`. + /// assert_eq!(a, 1); + /// ``` #[stable(feature = "lazy_bool_to_option", since = "1.50.0")] #[rustc_const_unstable(feature = "const_bool_to_option", issue = "91917")] #[inline] |