Rust release · Nov 10, 2016

Rust 1.13: what's new, what was stabilized

Short answerRust 1.13 was released on Nov 10, 2016: 3 language stabilizations ([Stabilize the ? operator][36995]. ? is a simple way to propagate); 5 newly stable APIs (checked_abs, wrapping_abs, overflowing_abs, RefCell::try_borrow, ...); 7 compatibility notes that can affect existing code.

Nov 10, 2016release date

3language stabilizations

5APIs stabilized

-new edition

← Rust 1.12 All versions Rust 1.14 →

Language features stabilized

[Stabilize the ? operator][36995]. ? is a simple way to propagate
[Stabilize macros in type position][36014]. Described in [RFC 873].
[Stabilize attributes on statements][36995]. Described in [RFC 0016].

5 APIs stabilized

checked_abs, wrapping_abs, overflowing_abs, RefCell::try_borrow, RefCell::try_borrow_mut

Can it break my build?

The release lists these compatibility notes. Most only affect rare code, but read them before you raise your toolchain in CI:

[SipHasher] is deprecated. Use [DefaultHasher].
[Deny (by default) transmuting from fn item types to pointer-sized
[Fix #[derive] for empty tuple structs/variants][35728].
[Issue deprecation warnings for safe accesses to extern statics][36173]
[Fix lifetime rules for 'if' conditions][36029].
[Inherit overflow checks for sum and product][36372].
[Forbid user-defined macros named "macro_rules"][36730].

Use it

rustup update stable        # get the newest release
rustup install 1.13          # or exactly this one
rustup override set 1.13     # pin a project to it

To require at least this version from users of your crate, set rust-version = "1.13" under [package] in Cargo.toml. Cargo then refuses to build it on older compilers with a clear message, and with resolver 3 (the default on the 2024 edition, Rust 1.85+) it also prefers dependency versions that support it.

Full release notes

Language

[Stabilize the ? operator][36995]. ? is a simple way to propagate errors, like the try! macro, described in [RFC 0243].
[Stabilize macros in type position][36014]. Described in [RFC 873].
[Stabilize attributes on statements][36995]. Described in [RFC 0016].
[Fix #[derive] for empty tuple structs/variants][35728]
[Fix lifetime rules for 'if' conditions][36029]
[Avoid loading and parsing unconfigured non-inline modules][36482]

Compiler

[Add the -C link-arg argument][36574]
[Remove the old AST-based backend from rustc_trans][35764]
[Don't enable NEON by default on armv7 Linux][35814]
[Fix debug line number info for macro expansions][35238]
[Do not emit "class method" debuginfo for types that are not DICompositeType][36008]
[Warn about multiple conflicting #[repr] hints][34623]
[When sizing DST, don't double-count nested struct prefixes][36351]
[Default RUST_MIN_STACK to 16MiB for now][36505]
[Improve rlib metadata format][36551]. Reduces rlib size significantly.
[Reject macros with empty repetitions to avoid infinite loop][36721]
[Expand macros without recursing to avoid stack overflows][36214]

Diagnostics

[Replace macro backtraces with labeled local uses][35702]
[Improve error message for misplaced doc comments][33922]
[Buffer unix and lock windows to prevent message interleaving][35975]
[Update lifetime errors to specifically note temporaries][36171]
[Special case a few colors for Windows][36178]
[Suggest use self when such an import resolves][36289]
[Be more specific when type parameter shadows primitive type][36338]
Many minor improvements

Compile-time Optimizations

[Compute and cache HIR hashes at beginning][35854]
[Don't hash types in loan paths][36004]
[Cache projections in trans][35761]
[Optimize the parser's last token handling][36527]
[Only instantiate #[inline] functions in codegen units referencing them][36524]. This leads to big improvements in cases where crates export define many inline functions without using them directly.
[Lazily allocate TypedArena's first chunk][36592]
[Don't allocate during default HashSet creation][36734]

Stabilized APIs

[checked_abs]
[wrapping_abs]
[overflowing_abs]
[RefCell::try_borrow]
[RefCell::try_borrow_mut]

Libraries

[Add assert_ne! and debug_assert_ne!][35074]
[Make vec_deque::Drain, hash_map::Drain, and hash_set::Drain covariant][35354]
[Implement AsRef<[T]> for std::slice::Iter][35559]
[Implement Debug for std::vec::IntoIter][35707]
[CString: avoid excessive growth just to 0-terminate][35871]
[Implement CoerceUnsized for {Cell, RefCell, UnsafeCell}][35627]
[Use arc4rand on FreeBSD][35884]
[memrchr: Correct aligned offset computation][35969]
[Improve Demangling of Rust Symbols][36059]
[Use monotonic time in condition variables][35048]
[Implement Debug for std::path::{Components,Iter}][36101]
[Implement conversion traits for char][35755]
[Fix illegal instruction caused by overflow in channel cloning][36104]
[Zero first byte of CString on drop][36264]
[Inherit overflow checks for sum and product][36372]
[Add missing Eq implementations][36423]
[Implement Debug for DirEntry][36631]
[When getaddrinfo returns EAI_SYSTEM retrieve actual error from errno][36754]
[SipHasher] is deprecated. Use [DefaultHasher].
[Implement more traits for std::io::ErrorKind][35911]
[Optimize BinaryHeap bounds checking][36072]
[Work around pointer aliasing issue in Vec::extend_from_slice, extend_with_element][36355]
[Fix overflow checking in unsigned pow()][34942]

Cargo

This release includes security fixes to both curl and OpenSSL.
[Fix transitive doctests when panic=abort][cargo/3021]
[Add --all-features flag to cargo][cargo/3038]
[Reject path-based dependencies in cargo package][cargo/3060]
[Don't parse the home directory more than once][cargo/3078]
[Don't try to generate Cargo.lock on empty workspaces][cargo/3092]
[Update OpenSSL to 1.0.2j][cargo/3121]
[Add license and license_file to cargo metadata output][cargo/3110]
[Make crates-io registry URL optional in config; ignore all changes to source.crates-io][cargo/3089]
[Don't download dependencies from other platforms][cargo/3123]
[Build transitive dev-dependencies when needed][cargo/3125]
[Add support for per-target rustflags in .cargo/config][cargo/3157]
[Avoid updating registry when adding existing deps][cargo/3144]
[Warn about path overrides that won't work][cargo/3136]
[Use workspaces during cargo install][cargo/3146]
[Leak mspdbsrv.exe processes on Windows][cargo/3162]
[Add --message-format flag][cargo/3000]
[Pass target environment for rustdoc][cargo/3205]
[Use CommandExt::exec for cargo run on Unix][cargo/2818]
[Update curl and curl-sys][cargo/3241]
[Call rustdoc test with the correct cfg flags of a package][cargo/3242]

Tooling

[rustdoc: Add the --sysroot argument][36586]
[rustdoc: Fix a couple of issues with the search results][35655]
[rustdoc: remove the ! from macro URLs and titles][35234]
[gdb: Fix pretty-printing special-cased Rust types][35585]
[rustdoc: Filter more incorrect methods inherited through Deref][36266]

Misc

[Remove unmaintained style guide][35124]
[Add s390x support][36369]
[Initial work at Haiku OS support][36727]
[Add mips-uclibc targets][35734]
[Crate-ify compiler-rt into compiler-builtins][35021]
[Add rustc version info (git hash + date) to dist tarball][36213]
Many documentation improvements

Compatibility Notes

SipHasher is deprecated. Use DefaultHasher.
Deny (by default) transmuting from fn item types to pointer-sized types. Continuing the long transition to zero-sized fn items, per RFC 401.
[Fix #[derive] for empty tuple structs/variants]35728. Part of RFC 1506.
Issue deprecation warnings for safe accesses to extern statics
Fix lifetime rules for 'if' conditions.
Inherit overflow checks for sum and product.
Forbid user-defined macros named "macro_rules".

Release notes from the Rust project's RELEASES.md (MIT or Apache-2.0); summaries above are ours.