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Version 1.41.0 (2020-01-30)
===========================
Language
--------
- [You can now pass type parameters to foreign items when implementing
traits.][65879] E.g. You can now write `impl<T> From<Foo> for Vec<T> {}`.
- [You can now arbitrarily nest receiver types in the `self` position.][64325] E.g. you can
now write `fn foo(self: Box<Box<Self>>) {}`. Previously only `Self`, `&Self`,
`&mut Self`, `Arc<Self>`, `Rc<Self>`, and `Box<Self>` were allowed.
- [You can now use any valid identifier in a `format_args` macro.][66847]
Previously identifiers starting with an underscore were not allowed.
- [Visibility modifiers (e.g. `pub`) are now syntactically allowed on trait items and
enum variants.][66183] These are still rejected semantically, but
can be seen and parsed by procedural macros and conditional compilation.
Compiler
--------
- [Rustc will now warn if you have unused loop `'label`s.][66325]
- [Removed support for the `i686-unknown-dragonfly` target.][67255]
- [Added tier 3 support\* for the `riscv64gc-unknown-linux-gnu` target.][66661]
- [You can now pass an arguments file passing the `@path` syntax
to rustc.][66172] Note that the format differs somewhat from what is
found in other tooling; please see [the documentation][argfile-docs] for
more information.
- [You can now provide `--extern` flag without a path, indicating that it is
available from the search path or specified with an `-L` flag.][64882]
\* Refer to Rust's [platform support page][forge-platform-support] for more
information on Rust's tiered platform support.
[argfile-docs]: https://doc.rust-lang.org/nightly/rustc/command-line-arguments.html#path-load-command-line-flags-from-a-path
Libraries
---------
- [The `core::panic` module is now stable.][66771] It was already stable
through `std`.
- [`NonZero*` numerics now implement `From<NonZero*>` if it's a smaller integer
width.][66277] E.g. `NonZeroU16` now implements `From<NonZeroU8>`.
- [`MaybeUninit<T>` now implements `fmt::Debug`.][65013]
Stabilized APIs
---------------
- [`Result::map_or`]
- [`Result::map_or_else`]
- [`std::rc::Weak::weak_count`]
- [`std::rc::Weak::strong_count`]
- [`std::sync::Weak::weak_count`]
- [`std::sync::Weak::strong_count`]
Cargo
-----
- [Cargo will now document all the private items for binary crates
by default.][cargo/7593]
- [`cargo-install` will now reinstall the package if it detects that it is out
of date.][cargo/7560]
- [Cargo.lock now uses a more git friendly format that should help to reduce
merge conflicts.][cargo/7579]
- [You can now override specific dependencies's build settings][cargo/7591] E.g.
`[profile.dev.overrides.image] opt-level = 2` sets the `image` crate's
optimisation level to `2` for debug builds. You can also use
`[profile.<profile>.build_overrides]` to override build scripts and
their dependencies.
Misc
----
- [You can now specify `edition` in documentation code blocks to compile the block
for that edition.][66238] E.g. `edition2018` tells rustdoc that the code sample
should be compiled the 2018 edition of Rust.
- [You can now provide custom themes to rustdoc with `--theme`, and check the
current theme with `--check-theme`.][54733]
- [You can use `#[cfg(doc)]` to compile an item when building documentation.][61351]
Compatibility Notes
-------------------
- [As previously announced 1.41.0 will be the last tier 1 release for 32-bit
Apple targets.][apple-32bit-drop] This means that the source code is still
available to build, but the targets are no longer being tested and release
binaries for those platforms will no longer be distributed by the Rust project.
Please refer to the linked blog post for more information.
[54733]: rust-lang/rust#54733
[61351]: rust-lang/rust#61351
[67255]: rust-lang/rust#67255
[66661]: rust-lang/rust#66661
[66771]: rust-lang/rust#66771
[66847]: rust-lang/rust#66847
[66238]: rust-lang/rust#66238
[66277]: rust-lang/rust#66277
[66325]: rust-lang/rust#66325
[66172]: rust-lang/rust#66172
[66183]: rust-lang/rust#66183
[65879]: rust-lang/rust#65879
[65013]: rust-lang/rust#65013
[64882]: rust-lang/rust#64882
[64325]: rust-lang/rust#64325
[cargo/7560]: rust-lang/cargo#7560
[cargo/7579]: rust-lang/cargo#7579
[cargo/7591]: rust-lang/cargo#7591
[cargo/7593]: rust-lang/cargo#7593
[`Result::map_or_else`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.map_or_else
[`Result::map_or`]: https://doc.rust-lang.org/std/result/enum.Result.html#method.map_or
[`std::rc::Weak::weak_count`]: https://doc.rust-lang.org/std/rc/struct.Weak.html#method.weak_count
[`std::rc::Weak::strong_count`]: https://doc.rust-lang.org/std/rc/struct.Weak.html#method.strong_count
[`std::sync::Weak::weak_count`]: https://doc.rust-lang.org/std/sync/struct.Weak.html#method.weak_count
[`std::sync::Weak::strong_count`]: https://doc.rust-lang.org/std/sync/struct.Weak.html#method.strong_count
[apple-32bit-drop]: https://blog.rust-lang.org/2020/01/03/reducing-support-for-32-bit-apple-targets.html- Loading branch information
