Fix nit and add link for Cow
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837a761b39
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1 changed files with 8 additions and 32 deletions
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@ -1684,14 +1684,6 @@ mod use_keyword {}
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/// of `shorter`, thus the constraint is respected:
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/// of `shorter`, thus the constraint is respected:
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///
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///
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/// ```rust
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/// ```rust
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/// fn select<'a, 'b: 'a>(s1: &'a str, s2: &'b str, second: bool) -> &'a str {
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/// if second {
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/// s2
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/// } else {
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/// s1
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/// }
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/// }
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///
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/// fn select_where<'a, 'b>(s1: &'a str, s2: &'b str, second: bool) -> &'a str
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/// fn select_where<'a, 'b>(s1: &'a str, s2: &'b str, second: bool) -> &'a str
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/// where
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/// where
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/// 'b: 'a,
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/// 'b: 'a,
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@ -1706,30 +1698,18 @@ mod use_keyword {}
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/// let outer = String::from("Long living ref");
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/// let outer = String::from("Long living ref");
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/// let longer = &outer;
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/// let longer = &outer;
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/// {
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/// {
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/// let inner = String::from("Long living ref");
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/// let inner = String::from("Short living ref");
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/// let shorter = &inner;
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/// let shorter = &inner;
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///
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///
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/// assert_eq!(select(shorter, longer, false), shorter);
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/// assert_eq!(select(shorter, longer, true), longer);
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///
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/// assert_eq!(select_where(shorter, longer, false), shorter);
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/// assert_eq!(select_where(shorter, longer, false), shorter);
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/// assert_eq!(select_where(shorter, longer, true), longer);
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/// assert_eq!(select_where(shorter, longer, true), longer);
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/// }
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/// }
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/// ```
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/// ```
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///
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///
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/// On the other hand, this will not compile: `shorter` does not have a lifetime
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/// On the other hand, this will not compile: `shorter` does not have a lifetime
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/// that respects the constraint imposed by the `select` and `select_where`
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/// that respects the constraint imposed by the `select_where` functions.
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/// functions.
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///
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///
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/// ```rust,compile_fail,E0597
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/// ```rust,compile_fail,E0597
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/// # fn select<'a, 'b: 'a>(s1: &'a str, s2: &'b str, second: bool) -> &'a str {
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/// # if second {
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/// # s2
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/// # } else {
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/// # s1
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/// # }
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/// # }
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/// #
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/// # fn select_where<'a, 'b>(s1: &'a str, s2: &'b str, second: bool) -> &'a str
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/// # fn select_where<'a, 'b>(s1: &'a str, s2: &'b str, second: bool) -> &'a str
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/// # where
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/// # where
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/// # 'b: 'a,
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/// # 'b: 'a,
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@ -1742,17 +1722,14 @@ mod use_keyword {}
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/// # }
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/// # }
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/// let outer = String::from("Long living ref");
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/// let outer = String::from("Long living ref");
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/// let longer = &outer;
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/// let longer = &outer;
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/// let res1;
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/// let res;
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/// let res2;
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/// {
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/// {
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/// let inner = String::from("Long living ref");
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/// let inner = String::from("Short living ref");
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/// let shorter = &inner;
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/// let shorter = &inner;
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///
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///
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/// res1 = select(longer, shorter, false);
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/// res = select_where(longer, shorter, false);
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/// res2 = select_where(longer, shorter, false);
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/// }
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/// }
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/// assert_eq!(res1, &outer);
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/// assert_eq!(res, &outer);
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/// assert_eq!(res2, &outer);
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/// ```
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/// ```
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///
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///
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/// `where` can also be used to express more complicated constraints that cannot
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/// `where` can also be used to express more complicated constraints that cannot
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@ -1771,12 +1748,11 @@ mod use_keyword {}
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/// assert_eq!(first_or_default(Vec::<i32>::new().into_iter()), 0);
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/// assert_eq!(first_or_default(Vec::<i32>::new().into_iter()), 0);
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/// ```
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/// ```
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///
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///
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/// `where` is available anywhere generic and lifetime parameters are available:
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/// `where` is available anywhere generic and lifetime parameters are available,
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/// as can be seen in the [`Cow`](crate::borrow::Cow) from the standard library:
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///
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///
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/// ```rust
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/// ```rust
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/// # #![allow(dead_code)]
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/// # #![allow(dead_code)]
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/// // The Cow type from the standard library uses where to impose constraints
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/// // on its parameters.
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/// pub enum Cow<'a, B>
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/// pub enum Cow<'a, B>
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/// where
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/// where
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/// B: 'a + ToOwned + ?Sized,
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/// B: 'a + ToOwned + ?Sized,
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