Use "an" before "i32"
(Minor typo fix.)
Since the word `i32` starts with a vowel, the indefinite article should use "an", not "a" \[[1](http://www.dictionary.com/browse/an)\]. (Previously there was one instance of "an i32" and two instances of "a i32", so at least something is wrong!) Since I believe that "an" is the correct form, I aligned everything with that.
Add missing apostrophe.
(Minor typo fix.)
The "support" in this case is possessed by the "programmer", and that ownership should be indicated by an apostrophe.
(Minor typo fix.)
Since the word `i32` starts with a vowel, the indefinite article should use "an", not "a" \[[1](http://www.dictionary.com/browse/an)\]. (Previously there was one instance of "an i32" and two instances of "a i32", so at least something is wrong!) Since I believe that "an" is the correct form, I aligned everything with that.
Fix Markdown list formatting.
The Markdown engine used by the book can cope with a single leading space on the list marker:
Like this:
* List item
Rather than like this:
* List item
… but it’s not the typical convention employed in the book, and moreover the Markdown engine used for producing the error index *can’t* cope with it (its behaviour looks like a bug, as it appears to lose one of the two line breaks as well, but that’s immaterial here).
So, we shift to a single convention which doesn’t trigger bugs in the Markdown renderer.
----
See https://doc.rust-lang.org/error-index.html#E0458 and https://doc.rust-lang.org/error-index.html#E0101 for the bad current rendering in the error index.
Simplify notes on testing and concurrency
The start of the notes on tests running concurrently, added in https://github.com/rust-lang/rust/pull/37766 read a little awkwardly. This PR fixes that and simplifies the wording a bit.
r? @steveklabnik
The Markdown engine used by the book can cope with a single leading space
on the list marker:
Like this:
* List item
Rather than like this:
* List item
… but it’s not the typical convention employed in the book, and moreover
the Markdown engine used for producing the error index *can’t* cope with
it (its behaviour looks like a bug, as it appears to lose one of the two
line breaks as well, but that’s immaterial here).
So, we shift to a single convention which doesn’t trigger bugs in the
Markdown renderer.
Calling if-let a combination of if and let is confusing, as some may be led to believe that it's a literal combination, instead of syntactic sugar added to the language as a convenience. What's there to stop someone from thinking if-let is just if and let together?
I do think this article does a good job of implying what's really going on; however, I was only able to notice this after I had begun to understand if/while-let statements, courtesy of the Rust IRC chat.
Basically, this article lacks the clarity and explicitness an inexperienced programmer like me needs in order to understand the contents fully. This is shown by my inability to understand the if-let concept from this page of the Book alone.
I think convenience, sugar, and (if-let != if + let) should all be made mention of in a clear, explicit manner. I lack confidence in my understanding of this issue, so I wrote just enough to hopefully get my thoughts across.
Avoid using locally installed Source Code Pro font (fixes#24355).
In some versions of this font the ampersands are drawn badly.
A doc tree built with this change is at https://storage.googleapis.com/mbp-rust-builds/fonts/doc/std/index.html
I'm not seeing this problem locally so I'm not sure this fixes it, but based on the diagnosis in the bug it should.
I've made this a minimal change by only removing the one problematic font but maybe for consistency every font should be read from the Rust docs tree?
Update book/ffi to use catch_unwind
r? @GuillaumeGomez
The doc mentioned to spawn a new thread instead of using catch_unwind, which has been the recommended way to catch panics for foreign function interfaces for a few releases now.
This commit fixes that.
reference: fix definition of :tt
The reference says that $x:tt matches "either side of the `=>` in macro_rules` which is technically true but completely uninformative. This changes that bullet point to what the book says (a single token or sequence of token trees inside brackets).
r? @GuillaumeGomez
The doc mentioned to spawn a new thread instead of using catch_unwind, which has been the recommended way to catch panics for foreign function interfaces for a few releases now.
The reference says that $x:tt matches "either side of the `=>` in macro_rules` which is technically true but completely uninformative. This changes that bullet point to what the book says (a single token or sequence of token trees inside brackets).
Separate out of bounds errors from character boundary errors, and print
more details for character boundary errors.
Example:
&"abcαβγ"[..4]
thread 'str::test_slice_fail_boundary_1' panicked at 'byte index 4 is not
a char boundary; it is inside `α` (bytes 3..5) of `abcαβγ`'
Use literal 5 instead of five in book section 4.1
The other two code snippets in this sentence are valid code, so it makes more sense to use the literal `5` rather than the invalid symbol `five`.
Clarify the reference's status.
The former wording only gave part of the picture, we want to be crystal
clear about this.
/cc @petrochenkov, who had concerns about https://github.com/rust-lang/rust/pull/37820
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?
