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Guide: Pointers: cruft removal + minor clarifications #18338

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Nov 5, 2014
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Guide: Pointers: cruft removal + minor clarifications #18338

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Guide: minor clarifications for the Pointers part
chastell Oct 26, 2014
9be04d5
Guide: drop line-number cruft from elided error examples
chastell Oct 26, 2014
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16 changes: 8 additions & 8 deletions src/doc/guide.md
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Original file line number Diff line number Diff line change
Expand Up @@ -3419,7 +3419,7 @@ let y = &mut x;
Rust will complain:

```{ignore,notrust}
6:19 error: cannot borrow immutable local variable `x` as mutable
error: cannot borrow immutable local variable `x` as mutable
let y = &mut x;
^
```
Expand Down Expand Up @@ -3463,7 +3463,7 @@ note: previous borrow ends here

This is a big error message. Let's dig into it for a moment. There are three
parts: the error and two notes. The error says what we expected, we cannot have
two pointers that point to the same memory.
two mutable pointers that point to the same memory.

The two notes give some extra context. Rust's error messages often contain this
kind of extra information when the error is complex. Rust is telling us two
Expand Down Expand Up @@ -3734,10 +3734,10 @@ let y = &mut x;
This gives us this error:

```{notrust,ignore}
8:7 error: cannot use `*x` because it was mutably borrowed
error: cannot use `*x` because it was mutably borrowed
*x;
^~
6:19 note: borrow of `x` occurs here
note: borrow of `x` occurs here
let y = &mut x;
^
```
Expand All @@ -3762,7 +3762,7 @@ value that must persist as long as any of several referrers, read on.

## Rc and Arc

Sometimes, you need a variable that is referenced from multiple places
Sometimes you need a variable that is referenced from multiple places
(immutably!), lasting as long as any of those places, and disappearing when it
is no longer referenced. For instance, in a graph-like data structure, a node
might be referenced from all of its neighbors. In this case, it is not possible
Expand Down Expand Up @@ -3858,7 +3858,7 @@ match x {
```

If you're matching on an enum which has variants, you can use `..` to
ignore the value in the variant:
ignore the value and type in the variant:

```{rust}
enum OptionalInt {
Expand Down Expand Up @@ -4530,8 +4530,8 @@ So this would give us the numbers from `2-100`. Well, almost! If you
compile the example, you'll get a warning:

```{notrust,ignore}
2:37 warning: unused result which must be used: iterator adaptors are lazy and
do nothing unless consumed, #[warn(unused_must_use)] on by default
warning: unused result which must be used: iterator adaptors are lazy and
do nothing unless consumed, #[warn(unused_must_use)] on by default
range(1i, 100i).map(|x| x + 1i);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```
Expand Down