change the `box_free` lang item to accept pointers to unsized types
in miri we use the `box_free` lang item as the destructor for `Box` objects, since the function's api matches that of an `fn drop(&mut self)` in a hypothetical `impl<T: ?Sized> Drop for Box<T>` exactly.
This works fine except if we insert a check in the `size_of` intrinsic to ensure that it is only called with sized types, since the `box_free` lang item calls that intrinsic.
cc @eddyb
no clue who to r? here, probably lang team?
Update testing.md to reflect changes to cargo new
`cargo new` now creates a `src/lib.rs` with a `tests` module by default. I've updated the earlier examples in this doc to reflect this. However, I don't know how we want to approach the "introduction" to idiomatic testing that follows in "the tests module" section. I _think_ it should be broken apart, with the module concept being introduced early on, and the `super` concept being addressed when we hit the `add_two` example. I'd like to get agreement on that being the right approach before I do it though.
I _also_ removed the `#fn main() {}` hidden at the beginning of each example, as these cause Rust Playground to not treat the file as a set of tests that it can run. Removing it _should_ cause Rust Playground to display a "Test >" button in the top left when a user runs the code, which will allow them to see the test runner output.
While the commit message on this one sounds terrible, it's really not so
bad. The issue is that our test runner _expects_ a `fn main() {}` in
code blocks that it'll test, but this code really shouldn't have them.
If it did, then clicking the "play" link in the docs would result in
play.rust-lang.org not treating this code as a test example to be run.
Without these changes, play.rust-lang.org (as of today) would wrap
our examples in `fn main() {}`. This prevents the user from being able
to easily run the tests.
Document the question mark operator in reference and the book's syntax index
The question mark operator will be stabilized for the Rust 1.13 release (unfortunately). Even though I don't like the operator, it still should be documented in the syntax index in the book and in the reference.
Maybe there are people who also want to change the book's chapters on error handling, depending on their views of what idiomatic error handling is, now that the operator is stable, but I don't want to and I'd prefer to keep this PR focused on the reference and syntax index only.
Please also apply this PR to the beta branch of rust.
book: Removed platform compatibility table, link to the forge
The content is duplicated, and it doesn't need to be in this location.
It's mostly trivia that doesn't apply to most of the audience.
The forge is up to date.
r? @steveklabnik cc @alexcrichton
Add error note to illegal code snippet
Mark intentionally invalid code snippet in documentation as such with a comment. Similar comments used elsewhere in this file.
r? @steveklabnik
Make it clear that the reference isn't normative
Any time someone edits the reference, it has to be taken very seriously,
since it's the closest thing we have to a specification. This commit
adds language which indicates that this is not a normative document,
which makes it easier to make tweaks without worrying about forever
harming the future of Rust by painting ourselves in a corner.
r? @aturon
`cargo new` now creates a `src/lib.rs` with a `tests` module by default. I've updated the earlier examples in this doc to reflect this. However, I don't know how we want to approach the "introduction" to idiomatic testing that follows in "the tests module" section. I _think_ it should be broken apart, with the module concept being introduced early on, and the `super` concept being addressed when we hit the `add_two` example. I'd like to get agreement on that being the right approach before I do it though.
I _also_ removed the `#fn main() {}` hidden at the beginning of each example, as these cause Rust Playground to not treat the file as a set of tests that it can run. Removing it _should_ cause Rust Playground to display a "Test >" button in the top left when a user runs the code, which will allow them to see the test runner output.
Stabilize `..` in tuple (struct) patterns
I'd like to nominate `..` in tuple and tuple struct patterns for stabilization.
This feature is a relatively small extension to existing stable functionality and doesn't have known blockers.
The feature first appeared in Rust 1.10 6 months ago.
An example of use: https://github.com/rust-lang/rust/pull/36203
Closes https://github.com/rust-lang/rust/issues/33627
r? @nikomatsakis
Add example using Self to reference
When I first came across `Self` I had a hard time finding references to it in the docs (and it's also been asked about on [StackOverflow](http://stackoverflow.com/questions/32304595/whats-the-difference-between-self-and-self).
I hope this example provides someone who comes across it for the first time a little more help. If there is a better way to show an example actually using `Self`, I'm happy to modify this. It was just the simplest place to start I could see.
The content is duplicated, and it doesn't need to be in this location.
It's mostly trivia that doesn't apply to most of the audience.
The forge is up to date.
Fix some mistakes in HRTB docs
The example code for higher-ranked trait bounds on closures had an unnecessary `mut` which was confusing, and the text referred to an mutable reference which does not exist in the code (and isn't needed). Removed the `mut`s and fixed the text to better describe the actual error for the failing example.
Thanks to csd_ on IRC for pointing out these problems!
r? @steveklabnik
I followed the "Testing" chapter using Rust 1.12.1 but there are some differences. By default the `tests` module is now also generated by `cargo new`, and the console output is updated.
Fix a error of 'book/deref-coercions.html'
The original sentence is:
> This example has two conversions: `Rc<String>` to `String` and then `String` to `&str`.
But it should be
> This example has two conversions: `Rc<String>` to `String` and then `String` to `str`.
or
> This example has two conversions: `&Rc<String>` to `&String` and then `&String` to `&str`.
I think the latter is more clearly.
r? @steveklabnik
The example code for higher-ranked trait bounds on closures had an
unnecessary `mut` which was confusing, and the text referred to an
mutable reference which does not exist in the code (and isn't needed).
Removed the `mut`s and fixed the text to better describe the actual
error for the failing example.
The original sentence is:
> This example has two conversions: `Rc<String>` to `String` and then `String` to `&str`.
But it should be
> This example has two conversions: `Rc<String>` to `String` and then `String` to `str`.
or
> This example has two conversions: `&Rc<String>` to `&String` and then `&String` to `&str`.
I think the latter is more clearly.
Explain motivation behind lifetimes
Start the lifetime section with an explanation of the issues that lack of explicit lifetimes cause and how the explicit lifetimes solve these.
----------------
I had really hard time figuring out why I would need to care about the explicit reference lifetimes when going through the book at first. With strong background in C++, I'm familiar with the dangling reference problem - but given the section seems to focus more on the lifetime syntax and various ways to define lifetimes on functions and structs, I was unable to understand how they are used to solve the reference problem.
This PR is an attempt at getting the reader to understand what the explicit lifetimes are used for and why they are an awesome thing instead of a bit of syntax that just has to be written.
It's been less than a week that I've been diving into Rust so I'm far from certain about the terminology and technical correctness. I tried mimicking the existing terminology from the lifetimes section, but still no promises on getting it right.
