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Update bool and ! docs #80590

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Merged
merged 2 commits into from
Jan 3, 2021
Merged

Update bool and ! docs #80590

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4af1112
Update `bool` and `!` docs
camelid Jan 1, 2021
4e76759
always demands -> requires
camelid Jan 2, 2021
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13 changes: 7 additions & 6 deletions library/std/src/primitive_docs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,8 +11,9 @@
/// `bool` implements various traits, such as [`BitAnd`], [`BitOr`], [`Not`], etc.,
/// which allow us to perform boolean operations using `&`, `|` and `!`.
///
/// `if` always demands a `bool` value. [`assert!`], which is an important macro in testing,
/// checks whether an expression returns `true` and panics if it isn't.
/// `if` requires a `bool` value as its conditional. [`assert!`], which is an
/// important macro in testing, checks whether an expression is `true` and panics
/// if it isn't.
Comment on lines +15 to +16
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Could reword

checks whether an expression is true and panics if it isn't.

as

panics if the expression is false.

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Are you suggesting

checks whether an expression is true and panics if it's false

or something else? I feel like maybe it's good enough as it is now, but open to changing it.

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Thankfully Rust isn’t Haskell and doesn’t have to worry about pervasive bottoms in data, so it really is the case for us that “isn’t true” necessarily implies “is false”. 😄

///
/// ```
/// let bool_val = true & false | false;
Expand All @@ -25,7 +26,7 @@
///
/// # Examples
///
/// A trivial example of the usage of `bool`,
/// A trivial example of the usage of `bool`:
///
/// ```
/// let praise_the_borrow_checker = true;
Expand Down Expand Up @@ -122,9 +123,9 @@ mod prim_bool {}
/// `!`, if we have to call [`String::from_str`] for some reason the result will be a
/// [`Result<String, !>`] which we can unpack like this:
///
/// ```ignore (string-from-str-error-type-is-not-never-yet)
/// #[feature(exhaustive_patterns)]
/// // NOTE: this does not work today!
/// ```
/// #![feature(exhaustive_patterns)]
/// use std::str::FromStr;
/// let Ok(s) = String::from_str("hello");
/// ```
///
Expand Down