Hello and welcome to the sixth issue of This Week in Rust, a weekly overview of Rust and its community.

What's cooking on master?

Issue churn this week was -17! A total of 63 PRs were merged this week, twice as many as last week. Not bad!

Breaking changes

The task local storage (TLS) API was cleaned up (there's still one PR in the queue that finishes it up).
DList was modernized.
extra::json now uses Iterator<char> rather than a @Reader
Various free-standing functions in f32 etc were removed
ref bindings in irrefutable patterns has been tightened up. This potentially fixes and breaks code. It's breaking because the compiler now rejects incorrect programs that it did not before.
str no longer encodes invalid utf-8.
extra::rope was removed
extra::net_ip and so on were removed. They were redundant names for extra::net::ip and such
Iterator::size_hint's lower bound is no longer an Option

Notable compiler additions, bugfixes, and cleanup

Unnecessary basic blocks were removed. This makes for much easier to read unoptimized IR.
Use of *int/*uint is now properly warned in FFI functions.
More default method fixes.
A needless copy was removed from immediate values (I'm pretty sure LLVM optimized it away when optimizations were on, not positive).
A lint for overqualified names was added.
SIMD arithmetic was implemented.
A graph abstraction and CFG was introduced, to unify how the various pieces of the compiler use graphs.
The maximum lifetime of stack closures is now constrained. Not quite sure what that means, but it fixes a segfault.
repr doesn't infinite loop on zero-sized structs (ie, unit structs).
Type parameter pretty printing was fixed, it now prints the type name rather than 'a and 'b and soforth.
mut in default method arguments is now allowed.
IR for calls with immediate return values was improved.
Exchange allocation headers (ie, the headers on ~T) were removed. This was a heroic effort by strcat and Luqman.
-Z trans-stats now reports perf-function statistics
Scopes were decoupled from LLVM basic blocks, improving unoptimized builds, and allowing more things in optimized builds to be inlined.
An infinite loop when recursively including modules was fixed.
An ICE involving struct-like enum variants was fixed.
The buildsystem cleans up old libraries when it needs to.
A bunch of managed boxes were removed from the AST.

Notable library additions, bugfixes, and cleanup

print! and println! macros were added (though #7779 renames them).
Ord now uses default methods, allowing you to get default implementations for everything but lt.
extra::Bitv now takes &[bool] rather than ~[uint].
x64 now uses large stacks (4 MiB) by default.
is_utf8 is now 22% faster
Metrics reporting and ratcheting was added to the test harness.
A DoubleEndedIterator was added.
A mut_split method was added to partition a &mut [T] into two pieces.
We now have pointer arithmetic.
A month's work of runtime work landed.
A safe, cross-platform mmap wrapper was added.
SmallIntMap and SmallIntSet have external iterators.
JSON parsing got 93% faster
Deque got a good cleanup and speedup.
vec now implements pop_opt and shift_opt methods.
A peek_ adaptor was added, which calls a closure on ever item before returning it. Mostly useful for debugging your iterators.

Documentation etc

vim improvements landed.
po4a support for translation was added.
libc::c_void is better documented.
Man pages for all the tools are now included.
The iterator tutorial was extended.

Meetings

The Tuesday meeting was all about split stacks and FFI. It's complex and above my ability to summarize, but from what I can tell no real consensus was made. But, it's the best enumeration of all the various issues surrounding split stacks that I've seen.

Discussion + Blog posts

From now on I'm going to just link to the reddit thread if there is one, as it often has additional comments or insights.