Was browsing somebody else's code and came across a snippet using labels. Looking around, it seems like there was an example for this in [rustbyexample](http://rustbyexample.com/flow_control/loop/nested.html) but none in trpl.
Updated "Installing Rust" and "After installation" to provide additional guidance to Windows users on including Rust in the Path system variable.
r? @steveklabnik
This PR fixes a snippet of code on the error handling chapter of \"The Rust Programming Language\".
//cc @steveklabnik
The docs state that trying to compile the snippet will yield the following error:
```bash
anon>:13:5: 20:6 error: non-exhaustive patterns: `_` not covered [E0004]
```
But instead the error received is:
```bash
<anon>:22:46: 22:56 error: unresolved name `NewRelease`
<anon>:22 std::io::println(descriptive_probability(NewRelease));
^~~~~~~~~~
<anon>:22:5: 22:21 error: unresolved name `std::io::println`
<anon>:22 std::io::println(descriptive_probability(NewRelease));
^~~~~~~~~~~~~~~~
error: aborting due to 2 previous errors
playpen: application terminated with error code 101
```
After applying this PR the expected error is returned:
```bash
anon>:13:5: 20:6 error: non-exhaustive patterns: `_` not covered [E0004]
<anon>:13 match probability(&event) {
<anon>:14 1.00 => \"certain\",
<anon>:15 0.00 => \"impossible\",
<anon>:16 0.00 ... 0.25 => \"very unlikely\",
<anon>:17 0.25 ... 0.50 => \"unlikely\",
<anon>:18 0.50 ... 0.75 => \"likely\",
...
<anon>:13:5: 20:6 help: see the detailed explanation for E0004
error: aborting due to previous error
```
Grammatical update (and passive -> active, but I'm not sure if "Rust" is often used as a subject in the book; feel free to revert that part for style, but keep the subject-verb agreement)
I am not mentioning #[unsafe_drop_flag] because it should go away
eventually, and also because it's just an attribute, it's not
really a use of the `unsafe` keyword.
Fixes#26345
I am not mentioning #[unsafe_drop_flag] because it should go away
eventually, and also because it's just an attribute, it's not
really a use of the `unsafe` keyword.
Fixes#26345
In Chapter 5.9 (References and Borrowing), there is an example [at the very end](https://doc.rust-lang.org/stable/book/references-and-borrowing.html#use-after-free) which shows that declaring a reference before declaring the variable that it points to results in a compilation error. The book does not really mention why this happens though -- in the sections before, it has described how different scopes affects the lifetime of resources, but there is no mention of how resources within the same scope work.
This confused me a little, so I asked on #rust and got the answer that the resources are destroyed in the reverse order that they are declared, but the book makes no mention of it (as far as I can find) -- except in Chapter 5.21 (Drop), where it says:
> When `x` goes out of scope at the end of `main()`, the code for `Drop` will run. `Drop` has one method, which is also called `drop()`. It takes a mutable reference to `self`.
>
> That’s it! The mechanics of `Drop` are very simple, but there are some subtleties. For example, values are dropped in the opposite order they are declared. [...]
---
I feel like Chapter 5.9 (References and Borrowing) is probably the best place to put this information (as I have done in my additions), since it deals with other types of referencing and borrowing. However, since English is not my native language, the wording of my additions perhaps are a little "off" -- any feedback on them is appreciated.
