Hello and welcome to the seventh issue of This Week in Rust, a weekly overview of Rust and its community. Things are calming down quite a bit, in that nothing extraordinarily exciting is happening. Lots of great work is being done everywhere, and good progress is being made in both bugfixes and cleanup. It has been a good week!

What's cooking on master?

Issue churn this week was -15. A total of 59 PRs were merged.

Breaking changes

The semantics of range_rev have changed. This will break your code without warning. It is now, to use interval notation, (hi, lo] rather than [hi, lo).
pub extern and priv extern have been removed from the language. This matches the previous similar change to impl. Place the visibility qualifier (pub/priv) on each item in the extern block instead.
&T (besides &'static T) is no longer allowed in @T.
The ThreadPerCore spawn mode has been removed, as it doesn't make sense with the new scheduler.
The consume methods of the hash containers has been replaced with an external iterator. The method name is the same, though.
Moved values can no longer be captured twice. This was a blatant soundness issue.
The swap_unwrap method of Option has been renamed to take_unwrap.
debug! statements generate no code unless you pass --cfg debug to rustc. This should help keep code size down and make your programs a (tiny bit) faster. Now you don't have to feel bad about having debug! in hot code.
The mutate_values method of HashMap has been removed.

Notable library additions, bugfixes, and cleanup

An iterator adaptor was added that endlessly repeats the iterator it is called on.
Generated test runners now have a -h/--help option.
Metric capturing + racheting has been added for benchmarks.
local_data now has a get_mut function.
extra::semver has been updated to SemVer 2.0.0.
Consuming iterators have been added for the hash structures.
extra::ringbuf now implements DoubleEndedIterator.
Eq now has a default implementation of ne.
extra::term now knows how to handle more attributes.
More containers implement FromIter. This means you can use .collect() to gather the elements from an iterator into those containers.
Task killing, failure, and exit code propagation in the new runtime has been implemented.

Notable compiler additions, bugfixes, and cleanup

syntax::attr has been modernized.
Tons of debuginfo work from mw this week!
Trait data structures have been cleaned up, as well as a default method fix.
Intrinsics now have much better codegen.
A no_implicit_prelude attribute has been added, which prevents prelude injection in the module hierarchy starting at the item which that attribute is added to.
C-style enum variants are now allowed in [T, ..n] expressions.
All language items are now optional. The compiler emits an error if a language item is used but not provided.
The removal of spanned<T> has begun.
Headers have been removed for ~str and ~[T] where T is unmanaged.

Documentation, tools, and other stuff

rustpkg now works when you don't give it a package ID. It builds/installs/cleans the package in the current directory, iff the current directory is in a rustpkg workspace.
--quiet is no longer passed to git during submodule operations, so you can see the progress of the huge LLVM download.
Documentation of the lint-controlling attributes was added.
rustpkg now handles cloning from local git repos.
The GtkSourceView highlighting file was improved.

Meetings

The Tuesday meeting discussed nothing at all of importance.