Rust 1.22.0

Language

• non_snake_case lint now allows extern no-mangle functions
• Now accepts underscores in unicode escapes
• T op= &T now works for numeric types. eg. let mut x = 2; x += &8;
• types that impl Drop are now allowed in const and static types

Compiler

• rustc now defaults to having 16 codegen units at debug on supported platforms.
• rustc will no longer inline in codegen units when compiling for debug This should decrease compile times for debug builds.
• strict memory alignment now enabled on ARMv6
• Remove support for the PNaCl target le32-unknown-nacl

Libraries

• Allow atomic operations up to 32 bits on armv5te_unknown_linux_gnueabi
• Box<Error> now impls From<Cow<str>>
• std::mem::Discriminant is now guaranteed to be Send + Sync
• fs::copy now returns the length of the main stream on NTFS.
• Properly detect overflow in Instant += Duration.
• impl Hasher for {&mut Hasher, Box<Hasher>}
• impl fmt::Debug for SplitWhitespace.
• Option<T> now impls Try This allows for using ? with Option types.

Stabilized APIs

Cargo

• Cargo will now build multi file examples in subdirectories of the examples folder that have a main.rs file.
• Changed [root] to [package] in Cargo.lock Packages with the old format will continue to work and can be updated with cargo update.
• Now supports vendoring git repositories

Misc

• libbacktrace is now available on Apple platforms.
• Stabilised the compile_fail attribute for code fences in doc-comments. This now lets you specify that a given code example will fail to compile.

Compatibility Notes

• The minimum Android version that rustc can build for has been bumped to 4.0 from 2.3
• Allowing T op= &T for numeric types has broken some type inference cases