Use result of the computation to prevent the compiler from optimising
too much. Change `_x` to `x` and therefore remove the paragraph about
the underscore.
Fixes#25855.
In the discussion of returning closures, it seems like the example code got simplified, but only the later copies got fixed. The final working code has `factory` returning `|x| x + num`, but the earlier code has `|x| vec.push(x)`.
The first form seemed to have more distracting characteristics, and the code wasn't right anyway, so I changed them to all use the second form, and updated the error messages.
r? @steveklabnik
Doc patch for #26120. Extra words here, because "value" is repeated.
I haven't read about whether/how it should go to stable (sorry), but I think it would help newcomers.
Thanks,
The text claimed 'any borrow must last for a _smaller_ scope than the
owner', however the accurate way of describing the comparison is
inclusive (i.e., 'less than or equal to' vs. 'less than').
The text claimed 'any borrow must last for a _smaller_ scope than the
owner', however the accurate way of describing the comparison is
inclusive (i.e., 'less than or equal to' vs. 'less than').
For a user following the path of reading Chapter 5: Syntax & Symantics
prior to Chapter 4: Learn Rust, this will be the first time they have
encountered executable tests inside documentation comments.
The test will fail because the `add_one` function is not defined in
the context of the doctest. This might not be the optimal place to
introduce and explain the `/// #` notation but I think it is important
that this snippet pass as a test when `rustdoc --test` is run against
it.
The doc indicates that you can replace 'before' with 'after' showing the use of try!. The two examples should be equivalent, but they are not.
In the File::create we were inducing a panic before in case of error, not propagating. It is important for newbies (like myself) to understand that try! propagates failures, while unwrap can induce a panic.
The other alternative is to make the 'before' File::create also manually handle Err like the other calls. Either way it would be consistent.
As mentioned in #25893 the copy trait is not very well explained for beginners. There is no clear mention that all primitive types implement the copy trait and there are not a lot of examples.
With this change I try to make it more visible and understandable for new users.
I myself have struggled with this, see [my question on stackoverflow](http://stackoverflow.com/questions/30540419/why-are-booleans-copyable-even-though-the-documentation-doesnt-indicate-that). And I want to make it more transparent for others.
I filed issue #25893 but I thought that I could give it a shot myself to relieve some of the work from the devs :)
If it is not well written or there are some changes to be made before it can be merged, let me know.
Cheers,
Mathieu
