/// 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]
/// 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]