2b399b5275
never_patterns: Parse match arms with no body
Never patterns are meant to signal unreachable cases, and thus don't take bodies:
```rust
let ptr: *const Option<!> = ...;
match *ptr {
None => { foo(); }
Some(!),
}
```
This PR makes rustc accept the above, and enforces that an arm has a body xor is a never pattern. This affects parsing of match arms even with the feature off, so this is delicate. (Plus this is my first non-trivial change to the parser).
~~The last commit is optional; it introduces a bit of churn to allow the new suggestions to be machine-applicable. There may be a better solution? I'm not sure.~~ EDIT: I removed that commit
r? `@compiler-errors`
|
||
|---|---|---|
| .github | ||
| .reuse | ||
| compiler | ||
| library | ||
| LICENSES | ||
| src | ||
| tests | ||
| .editorconfig | ||
| .git-blame-ignore-revs | ||
| .gitattributes | ||
| .gitignore | ||
| .gitmodules | ||
| .mailmap | ||
| Cargo.lock | ||
| Cargo.toml | ||
| CODE_OF_CONDUCT.md | ||
| config.example.toml | ||
| configure | ||
| CONTRIBUTING.md | ||
| COPYRIGHT | ||
| LICENSE-APACHE | ||
| LICENSE-MIT | ||
| README.md | ||
| RELEASES.md | ||
| rust-bors.toml | ||
| rustfmt.toml | ||
| triagebot.toml | ||
| x | ||
| x.ps1 | ||
| x.py | ||
The Rust Programming Language
This is the main source code repository for Rust. It contains the compiler, standard library, and documentation.
Note: this README is for users rather than contributors. If you wish to contribute to the compiler, you should read CONTRIBUTING.md instead.
Table of Contents
Quick Start
Read "Installation" from The Book.
Installing from Source
The Rust build system uses a Python script called x.py to build the compiler,
which manages the bootstrapping process. It lives at the root of the project.
It also uses a file named config.toml to determine various configuration
settings for the build. You can see a full list of options in
config.example.toml.
The x.py command can be run directly on most Unix systems in the following
format:
./x.py <subcommand> [flags]
This is how the documentation and examples assume you are running x.py.
See the rustc dev guide if this does not work on your
platform.
More information about x.py can be found by running it with the --help flag
or reading the rustc dev guide.
Dependencies
Make sure you have installed the dependencies:
python3 or 2.7git- A C compiler (when building for the host,
ccis enough; cross-compiling may need additional compilers) curl(not needed on Windows)pkg-configif you are compiling on Linux and targeting Linuxlibiconv(already included with glibc on Debian-based distros)
To build Cargo, you'll also need OpenSSL (libssl-dev or openssl-devel on
most Unix distros).
If building LLVM from source, you'll need additional tools:
g++,clang++, or MSVC with versions listed on LLVM's documentationninja, or GNUmake3.81 or later (Ninja is recommended, especially on Windows)cmake3.13.4 or laterlibstdc++-staticmay be required on some Linux distributions such as Fedora and Ubuntu
On tier 1 or tier 2 with host tools platforms, you can also choose to download
LLVM by setting llvm.download-ci-llvm = true.
Otherwise, you'll need LLVM installed and llvm-config in your path.
See the rustc-dev-guide for more info.
Building on a Unix-like system
Build steps
-
Clone the source with
git:git clone https://github.com/rust-lang/rust.git cd rust
-
Configure the build settings:
./configureIf you plan to use
x.py installto create an installation, it is recommended that you set theprefixvalue in the[install]section to a directory:./configure --set install.prefix=<path> -
Build and install:
./x.py build && ./x.py installWhen complete,
./x.py installwill place several programs into$PREFIX/bin:rustc, the Rust compiler, andrustdoc, the API-documentation tool. By default, it will also include Cargo, Rust's package manager. You can disable this behavior by passing--set build.extended=falseto./configure.
Configure and Make
This project provides a configure script and makefile (the latter of which just
invokes x.py). ./configure is the recommended way to programmatically
generate a config.toml. make is not recommended (we suggest using x.py
directly), but it is supported and we try not to break it unnecessarily.
./configure
make && sudo make install
configure generates a config.toml which can also be used with normal x.py
invocations.
Building on Windows
On Windows, we suggest using winget to install dependencies by running the following in a terminal:
winget install -e Python.Python.3
winget install -e Kitware.CMake
winget install -e Git.Git
Then edit your system's PATH variable and add: C:\Program Files\CMake\bin.
See
this guide on editing the system PATH
from the Java documentation.
There are two prominent ABIs in use on Windows: the native (MSVC) ABI used by Visual Studio and the GNU ABI used by the GCC toolchain. Which version of Rust you need depends largely on what C/C++ libraries you want to interoperate with. Use the MSVC build of Rust to interop with software produced by Visual Studio and the GNU build to interop with GNU software built using the MinGW/MSYS2 toolchain.
MinGW
MSYS2 can be used to easily build Rust on Windows:
-
Download the latest MSYS2 installer and go through the installer.
-
Run
mingw32_shell.batormingw64_shell.batfrom the MSYS2 installation directory (e.g.C:\msys64), depending on whether you want 32-bit or 64-bit Rust. (As of the latest version of MSYS2 you have to runmsys2_shell.cmd -mingw32ormsys2_shell.cmd -mingw64from the command line instead.) -
From this terminal, install the required tools:
# Update package mirrors (may be needed if you have a fresh install of MSYS2) pacman -Sy pacman-mirrors # Install build tools needed for Rust. If you're building a 32-bit compiler, # then replace "x86_64" below with "i686". If you've already got Git, Python, # or CMake installed and in PATH you can remove them from this list. # Note that it is important that you do **not** use the 'python2', 'cmake', # and 'ninja' packages from the 'msys2' subsystem. # The build has historically been known to fail with these packages. pacman -S git \ make \ diffutils \ tar \ mingw-w64-x86_64-python \ mingw-w64-x86_64-cmake \ mingw-w64-x86_64-gcc \ mingw-w64-x86_64-ninja -
Navigate to Rust's source code (or clone it), then build it:
python x.py setup user && python x.py build && python x.py install
MSVC
MSVC builds of Rust additionally require an installation of Visual Studio 2017
(or later) so rustc can use its linker. The simplest way is to get
Visual Studio, check the "C++ build tools" and "Windows 10 SDK" workload.
(If you're installing CMake yourself, be careful that "C++ CMake tools for Windows" doesn't get included under "Individual components".)
With these dependencies installed, you can build the compiler in a cmd.exe
shell with:
python x.py setup user
python x.py build
Right now, building Rust only works with some known versions of Visual Studio. If you have a more recent version installed and the build system doesn't understand, you may need to force rustbuild to use an older version. This can be done by manually calling the appropriate vcvars file before running the bootstrap.
CALL "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"
python x.py build
Specifying an ABI
Each specific ABI can also be used from either environment (for example, using the GNU ABI in PowerShell) by using an explicit build triple. The available Windows build triples are:
- GNU ABI (using GCC)
i686-pc-windows-gnux86_64-pc-windows-gnu
- The MSVC ABI
i686-pc-windows-msvcx86_64-pc-windows-msvc
The build triple can be specified by either specifying --build=<triple> when
invoking x.py commands, or by creating a config.toml file (as described in
Building on a Unix-like system), and passing
--set build.build=<triple> to ./configure.
Building Documentation
If you'd like to build the documentation, it's almost the same:
./x.py doc
The generated documentation will appear under doc in the build directory for
the ABI used. That is, if the ABI was x86_64-pc-windows-msvc, the directory
will be build\x86_64-pc-windows-msvc\doc.
Notes
Since the Rust compiler is written in Rust, it must be built by a precompiled "snapshot" version of itself (made in an earlier stage of development). As such, source builds require an Internet connection to fetch snapshots, and an OS that can execute the available snapshot binaries.
See https://doc.rust-lang.org/nightly/rustc/platform-support.html for a list of supported platforms. Only "host tools" platforms have a pre-compiled snapshot binary available; to compile for a platform without host tools you must cross-compile.
You may find that other platforms work, but these are our officially supported build environments that are most likely to work.
Getting Help
See https://www.rust-lang.org/community for a list of chat platforms and forums.
Contributing
See CONTRIBUTING.md.
License
Rust is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.
See LICENSE-APACHE, LICENSE-MIT, and COPYRIGHT for details.
Trademark
The Rust Foundation owns and protects the Rust and Cargo trademarks and logos (the "Rust Trademarks").
If you want to use these names or brands, please read the media guide.
Third-party logos may be subject to third-party copyrights and trademarks. See Licenses for details.