Initial import of 1.0.4
Bug: 178357400
Test: None
Change-Id: Ib3200dfe1be54505bfcc189e3bedb10f6249a83a
diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json
new file mode 100644
index 0000000..1f45e32
--- /dev/null
+++ b/.cargo_vcs_info.json
@@ -0,0 +1,5 @@
+{
+ "git": {
+ "sha1": "2449cbc9d927411e8c88802b120a002e2e3507aa"
+ }
+}
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..9105f94
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,30 @@
+name: CI
+
+on:
+ push:
+ pull_request:
+ schedule: [cron: "40 1 * * *"]
+
+jobs:
+ test:
+ name: Rust ${{matrix.rust}}
+ runs-on: ubuntu-latest
+ strategy:
+ fail-fast: false
+ matrix:
+ rust: [nightly, beta, stable, 1.31.0]
+ steps:
+ - uses: actions/checkout@v2
+ - uses: dtolnay/rust-toolchain@master
+ with:
+ toolchain: ${{matrix.rust}}
+ - run: cargo test
+
+ minimal:
+ name: Minimal versions
+ runs-on: ubuntu-latest
+ steps:
+ - uses: actions/checkout@v2
+ - uses: dtolnay/rust-toolchain@nightly
+ - run: cargo update -Z minimal-versions
+ - run: cargo test
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..6936990
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+/target
+**/*.rs.bk
+Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..56995ff
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,30 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+edition = "2018"
+name = "rustversion"
+version = "1.0.4"
+authors = ["David Tolnay <dtolnay@gmail.com>"]
+build = "build/build.rs"
+description = "Conditional compilation according to rustc compiler version"
+documentation = "https://docs.rs/rustversion"
+readme = "README.md"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/dtolnay/rustversion"
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+
+[lib]
+proc-macro = true
+[dev-dependencies.trybuild]
+version = "1.0.35"
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
new file mode 100644
index 0000000..268b002
--- /dev/null
+++ b/Cargo.toml.orig
@@ -0,0 +1,20 @@
+[package]
+name = "rustversion"
+version = "1.0.4"
+authors = ["David Tolnay <dtolnay@gmail.com>"]
+edition = "2018"
+license = "MIT OR Apache-2.0"
+description = "Conditional compilation according to rustc compiler version"
+repository = "https://github.com/dtolnay/rustversion"
+documentation = "https://docs.rs/rustversion"
+readme = "README.md"
+build = "build/build.rs"
+
+[lib]
+proc-macro = true
+
+[dev-dependencies]
+trybuild = "1.0.35"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
diff --git a/LICENSE b/LICENSE
new file mode 120000
index 0000000..6b579aa
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1 @@
+LICENSE-APACHE
\ No newline at end of file
diff --git a/LICENSE-APACHE b/LICENSE-APACHE
new file mode 100644
index 0000000..16fe87b
--- /dev/null
+++ b/LICENSE-APACHE
@@ -0,0 +1,201 @@
+ Apache License
+ Version 2.0, January 2004
+ http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+1. Definitions.
+
+ "License" shall mean the terms and conditions for use, reproduction,
+ and distribution as defined by Sections 1 through 9 of this document.
+
+ "Licensor" shall mean the copyright owner or entity authorized by
+ the copyright owner that is granting the License.
+
+ "Legal Entity" shall mean the union of the acting entity and all
+ other entities that control, are controlled by, or are under common
+ control with that entity. For the purposes of this definition,
+ "control" means (i) the power, direct or indirect, to cause the
+ direction or management of such entity, whether by contract or
+ otherwise, or (ii) ownership of fifty percent (50%) or more of the
+ outstanding shares, or (iii) beneficial ownership of such entity.
+
+ "You" (or "Your") shall mean an individual or Legal Entity
+ exercising permissions granted by this License.
+
+ "Source" form shall mean the preferred form for making modifications,
+ including but not limited to software source code, documentation
+ source, and configuration files.
+
+ "Object" form shall mean any form resulting from mechanical
+ transformation or translation of a Source form, including but
+ not limited to compiled object code, generated documentation,
+ and conversions to other media types.
+
+ "Work" shall mean the work of authorship, whether in Source or
+ Object form, made available under the License, as indicated by a
+ copyright notice that is included in or attached to the work
+ (an example is provided in the Appendix below).
+
+ "Derivative Works" shall mean any work, whether in Source or Object
+ form, that is based on (or derived from) the Work and for which the
+ editorial revisions, annotations, elaborations, or other modifications
+ represent, as a whole, an original work of authorship. For the purposes
+ of this License, Derivative Works shall not include works that remain
+ separable from, or merely link (or bind by name) to the interfaces of,
+ the Work and Derivative Works thereof.
+
+ "Contribution" shall mean any work of authorship, including
+ the original version of the Work and any modifications or additions
+ to that Work or Derivative Works thereof, that is intentionally
+ submitted to Licensor for inclusion in the Work by the copyright owner
+ or by an individual or Legal Entity authorized to submit on behalf of
+ the copyright owner. For the purposes of this definition, "submitted"
+ means any form of electronic, verbal, or written communication sent
+ to the Licensor or its representatives, including but not limited to
+ communication on electronic mailing lists, source code control systems,
+ and issue tracking systems that are managed by, or on behalf of, the
+ Licensor for the purpose of discussing and improving the Work, but
+ excluding communication that is conspicuously marked or otherwise
+ designated in writing by the copyright owner as "Not a Contribution."
+
+ "Contributor" shall mean Licensor and any individual or Legal Entity
+ on behalf of whom a Contribution has been received by Licensor and
+ subsequently incorporated within the Work.
+
+2. Grant of Copyright License. Subject to the terms and conditions of
+ this License, each Contributor hereby grants to You a perpetual,
+ worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+ copyright license to reproduce, prepare Derivative Works of,
+ publicly display, publicly perform, sublicense, and distribute the
+ Work and such Derivative Works in Source or Object form.
+
+3. Grant of Patent License. Subject to the terms and conditions of
+ this License, each Contributor hereby grants to You a perpetual,
+ worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+ (except as stated in this section) patent license to make, have made,
+ use, offer to sell, sell, import, and otherwise transfer the Work,
+ where such license applies only to those patent claims licensable
+ by such Contributor that are necessarily infringed by their
+ Contribution(s) alone or by combination of their Contribution(s)
+ with the Work to which such Contribution(s) was submitted. If You
+ institute patent litigation against any entity (including a
+ cross-claim or counterclaim in a lawsuit) alleging that the Work
+ or a Contribution incorporated within the Work constitutes direct
+ or contributory patent infringement, then any patent licenses
+ granted to You under this License for that Work shall terminate
+ as of the date such litigation is filed.
+
+4. Redistribution. You may reproduce and distribute copies of the
+ Work or Derivative Works thereof in any medium, with or without
+ modifications, and in Source or Object form, provided that You
+ meet the following conditions:
+
+ (a) You must give any other recipients of the Work or
+ Derivative Works a copy of this License; and
+
+ (b) You must cause any modified files to carry prominent notices
+ stating that You changed the files; and
+
+ (c) You must retain, in the Source form of any Derivative Works
+ that You distribute, all copyright, patent, trademark, and
+ attribution notices from the Source form of the Work,
+ excluding those notices that do not pertain to any part of
+ the Derivative Works; and
+
+ (d) If the Work includes a "NOTICE" text file as part of its
+ distribution, then any Derivative Works that You distribute must
+ include a readable copy of the attribution notices contained
+ within such NOTICE file, excluding those notices that do not
+ pertain to any part of the Derivative Works, in at least one
+ of the following places: within a NOTICE text file distributed
+ as part of the Derivative Works; within the Source form or
+ documentation, if provided along with the Derivative Works; or,
+ within a display generated by the Derivative Works, if and
+ wherever such third-party notices normally appear. The contents
+ of the NOTICE file are for informational purposes only and
+ do not modify the License. You may add Your own attribution
+ notices within Derivative Works that You distribute, alongside
+ or as an addendum to the NOTICE text from the Work, provided
+ that such additional attribution notices cannot be construed
+ as modifying the License.
+
+ You may add Your own copyright statement to Your modifications and
+ may provide additional or different license terms and conditions
+ for use, reproduction, or distribution of Your modifications, or
+ for any such Derivative Works as a whole, provided Your use,
+ reproduction, and distribution of the Work otherwise complies with
+ the conditions stated in this License.
+
+5. Submission of Contributions. Unless You explicitly state otherwise,
+ any Contribution intentionally submitted for inclusion in the Work
+ by You to the Licensor shall be under the terms and conditions of
+ this License, without any additional terms or conditions.
+ Notwithstanding the above, nothing herein shall supersede or modify
+ the terms of any separate license agreement you may have executed
+ with Licensor regarding such Contributions.
+
+6. Trademarks. This License does not grant permission to use the trade
+ names, trademarks, service marks, or product names of the Licensor,
+ except as required for reasonable and customary use in describing the
+ origin of the Work and reproducing the content of the NOTICE file.
+
+7. Disclaimer of Warranty. Unless required by applicable law or
+ agreed to in writing, Licensor provides the Work (and each
+ Contributor provides its Contributions) on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ implied, including, without limitation, any warranties or conditions
+ of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+ PARTICULAR PURPOSE. You are solely responsible for determining the
+ appropriateness of using or redistributing the Work and assume any
+ risks associated with Your exercise of permissions under this License.
+
+8. Limitation of Liability. In no event and under no legal theory,
+ whether in tort (including negligence), contract, or otherwise,
+ unless required by applicable law (such as deliberate and grossly
+ negligent acts) or agreed to in writing, shall any Contributor be
+ liable to You for damages, including any direct, indirect, special,
+ incidental, or consequential damages of any character arising as a
+ result of this License or out of the use or inability to use the
+ Work (including but not limited to damages for loss of goodwill,
+ work stoppage, computer failure or malfunction, or any and all
+ other commercial damages or losses), even if such Contributor
+ has been advised of the possibility of such damages.
+
+9. Accepting Warranty or Additional Liability. While redistributing
+ the Work or Derivative Works thereof, You may choose to offer,
+ and charge a fee for, acceptance of support, warranty, indemnity,
+ or other liability obligations and/or rights consistent with this
+ License. However, in accepting such obligations, You may act only
+ on Your own behalf and on Your sole responsibility, not on behalf
+ of any other Contributor, and only if You agree to indemnify,
+ defend, and hold each Contributor harmless for any liability
+ incurred by, or claims asserted against, such Contributor by reason
+ of your accepting any such warranty or additional liability.
+
+END OF TERMS AND CONDITIONS
+
+APPENDIX: How to apply the Apache License to your work.
+
+ To apply the Apache License to your work, attach the following
+ boilerplate notice, with the fields enclosed by brackets "[]"
+ replaced with your own identifying information. (Don't include
+ the brackets!) The text should be enclosed in the appropriate
+ comment syntax for the file format. We also recommend that a
+ file or class name and description of purpose be included on the
+ same "printed page" as the copyright notice for easier
+ identification within third-party archives.
+
+Copyright [yyyy] [name of copyright owner]
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
diff --git a/LICENSE-MIT b/LICENSE-MIT
new file mode 100644
index 0000000..31aa793
--- /dev/null
+++ b/LICENSE-MIT
@@ -0,0 +1,23 @@
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/METADATA b/METADATA
new file mode 100644
index 0000000..eb41a97
--- /dev/null
+++ b/METADATA
@@ -0,0 +1,20 @@
+name: "rustversion"
+description: "Conditional compilation according to rustc compiler version"
+third_party {
+ url {
+ type: HOMEPAGE
+ value: "https://crates.io/crates/rustversion"
+ }
+ url {
+ type: ARCHIVE
+ value: "https://static.crates.io/crates/rustversion/rustversion-1.0.4.crate"
+ }
+ version: "1.0.4"
+ # Dual-licensed, using the least restrictive per go/thirdpartylicenses#same.
+ license_type: NOTICE
+ last_upgrade_date {
+ year: 2021
+ month: 2
+ day: 19
+ }
+}
diff --git a/MODULE_LICENSE_APACHE2 b/MODULE_LICENSE_APACHE2
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/MODULE_LICENSE_APACHE2
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..46fc303
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1 @@
+include platform/prebuilts/rust:/OWNERS
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..5b97272
--- /dev/null
+++ b/README.md
@@ -0,0 +1,139 @@
+Compiler version cfg
+====================
+
+[<img alt="github" src="https://img.shields.io/badge/github-dtolnay/rustversion-8da0cb?style=for-the-badge&labelColor=555555&logo=github" height="20">](https://github.com/dtolnay/rustversion)
+[<img alt="crates.io" src="https://img.shields.io/crates/v/rustversion.svg?style=for-the-badge&color=fc8d62&logo=rust" height="20">](https://crates.io/crates/rustversion)
+[<img alt="docs.rs" src="https://img.shields.io/badge/docs.rs-rustversion-66c2a5?style=for-the-badge&labelColor=555555&logoColor=white&logo=data:image/svg+xml;base64,PHN2ZyByb2xlPSJpbWciIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgdmlld0JveD0iMCAwIDUxMiA1MTIiPjxwYXRoIGZpbGw9IiNmNWY1ZjUiIGQ9Ik00ODguNiAyNTAuMkwzOTIgMjE0VjEwNS41YzAtMTUtOS4zLTI4LjQtMjMuNC0zMy43bC0xMDAtMzcuNWMtOC4xLTMuMS0xNy4xLTMuMS0yNS4zIDBsLTEwMCAzNy41Yy0xNC4xIDUuMy0yMy40IDE4LjctMjMuNCAzMy43VjIxNGwtOTYuNiAzNi4yQzkuMyAyNTUuNSAwIDI2OC45IDAgMjgzLjlWMzk0YzAgMTMuNiA3LjcgMjYuMSAxOS45IDMyLjJsMTAwIDUwYzEwLjEgNS4xIDIyLjEgNS4xIDMyLjIgMGwxMDMuOS01MiAxMDMuOSA1MmMxMC4xIDUuMSAyMi4xIDUuMSAzMi4yIDBsMTAwLTUwYzEyLjItNi4xIDE5LjktMTguNiAxOS45LTMyLjJWMjgzLjljMC0xNS05LjMtMjguNC0yMy40LTMzLjd6TTM1OCAyMTQuOGwtODUgMzEuOXYtNjguMmw4NS0zN3Y3My4zek0xNTQgMTA0LjFsMTAyLTM4LjIgMTAyIDM4LjJ2LjZsLTEwMiA0MS40LTEwMi00MS40di0uNnptODQgMjkxLjFsLTg1IDQyLjV2LTc5LjFsODUtMzguOHY3NS40em0wLTExMmwtMTAyIDQxLjQtMTAyLTQxLjR2LS42bDEwMi0zOC4yIDEwMiAzOC4ydi42em0yNDAgMTEybC04NSA0Mi41di03OS4xbDg1LTM4Ljh2NzUuNHptMC0xMTJsLTEwMiA0MS40LTEwMi00MS40di0uNmwxMDItMzguMiAxMDIgMzguMnYuNnoiPjwvcGF0aD48L3N2Zz4K" height="20">](https://docs.rs/rustversion)
+[<img alt="build status" src="https://img.shields.io/github/workflow/status/dtolnay/rustversion/CI/master?style=for-the-badge" height="20">](https://github.com/dtolnay/rustversion/actions?query=branch%3Amaster)
+
+This crate provides macros for conditional compilation according to rustc
+compiler version, analogous to [`#[cfg(...)]`][cfg] and
+[`#[cfg_attr(...)]`][cfg_attr].
+
+[cfg]: https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute
+[cfg_attr]: https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute
+
+```toml
+[dependencies]
+rustversion = "1.0"
+```
+
+<br>
+
+## Selectors
+
+- <b>`#[rustversion::stable]`</b>
+ —<br>
+ True on any stable compiler.
+
+- <b>`#[rustversion::stable(1.34)]`</b>
+ —<br>
+ True on exactly the specified stable compiler.
+
+- <b>`#[rustversion::beta]`</b>
+ —<br>
+ True on any beta compiler.
+
+- <b>`#[rustversion::nightly]`</b>
+ —<br>
+ True on any nightly compiler or dev build.
+
+- <b>`#[rustversion::nightly(2019-01-01)]`</b>
+ —<br>
+ True on exactly one nightly.
+
+- <b>`#[rustversion::since(1.34)]`</b>
+ —<br>
+ True on that stable release and any later compiler, including beta and
+ nightly.
+
+- <b>`#[rustversion::since(2019-01-01)]`</b>
+ —<br>
+ True on that nightly and all newer ones.
+
+- <b>`#[rustversion::before(`</b><i>version or date</i><b>`)]`</b>
+ —<br>
+ Negative of *#[rustversion::since(...)]*.
+
+- <b>`#[rustversion::not(`</b><i>selector</i><b>`)]`</b>
+ —<br>
+ Negative of any selector; for example *#[rustversion::not(nightly)]*.
+
+- <b>`#[rustversion::any(`</b><i>selectors...</i><b>`)]`</b>
+ —<br>
+ True if any of the comma-separated selectors is true; for example
+ *#[rustversion::any(stable, beta)]*.
+
+- <b>`#[rustversion::all(`</b><i>selectors...</i><b>`)]`</b>
+ —<br>
+ True if all of the comma-separated selectors are true; for example
+ *#[rustversion::all(since(1.31), before(1.34))]*.
+
+- <b>`#[rustversion::attr(`</b><i>selector</i><b>`, `</b><i>attribute</i><b>`)]`</b>
+ —<br>
+ For conditional inclusion of attributes; analogous to `cfg_attr`.
+
+<br>
+
+## Use cases
+
+Providing additional trait impls as types are stabilized in the standard library
+without breaking compatibility with older compilers; in this case Pin\<P\>
+stabilized in [Rust 1.33][pin]:
+
+[pin]: https://blog.rust-lang.org/2019/02/28/Rust-1.33.0.html#pinning
+
+```rust
+#[rustversion::since(1.33)]
+use std::pin::Pin;
+
+#[rustversion::since(1.33)]
+impl<P: MyTrait> MyTrait for Pin<P> {
+ /* ... */
+}
+```
+
+Similar but for language features; the ability to control alignment greater than
+1 of packed structs was stabilized in [Rust 1.33][packed].
+
+[packed]: https://github.com/rust-lang/rust/blob/master/RELEASES.md#version-1330-2019-02-28
+
+```rust
+#[rustversion::attr(before(1.33), repr(packed))]
+#[rustversion::attr(since(1.33), repr(packed(2)))]
+struct Six(i16, i32);
+
+fn main() {
+ println!("{}", std::mem::align_of::<Six>());
+}
+```
+
+Augmenting code with `const` as const impls are stabilized in the standard
+library. This use of `const` as an attribute is recognized as a special case by
+the rustversion::attr macro.
+
+```rust
+use std::time::Duration;
+
+#[rustversion::attr(since(1.32), const)]
+fn duration_as_days(dur: Duration) -> u64 {
+ dur.as_secs() / 60 / 60 / 24
+}
+```
+
+<br>
+
+#### License
+
+<sup>
+Licensed under either of <a href="LICENSE-APACHE">Apache License, Version
+2.0</a> or <a href="LICENSE-MIT">MIT license</a> at your option.
+</sup>
+
+<br>
+
+<sub>
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in this crate by you, as defined in the Apache-2.0 license, shall
+be dual licensed as above, without any additional terms or conditions.
+</sub>
diff --git a/build/build.rs b/build/build.rs
new file mode 100644
index 0000000..2a8bc4a
--- /dev/null
+++ b/build/build.rs
@@ -0,0 +1,47 @@
+mod rustc;
+
+use std::env;
+use std::ffi::OsString;
+use std::fs;
+use std::path::Path;
+use std::process::{self, Command};
+
+fn main() {
+ let rustc = env::var_os("RUSTC").unwrap_or_else(|| OsString::from("rustc"));
+ let output = match Command::new(&rustc).arg("--version").output() {
+ Ok(output) => output,
+ Err(e) => {
+ let rustc = rustc.to_string_lossy();
+ eprintln!("Error: failed to run `{} --version`: {}", rustc, e);
+ process::exit(1);
+ }
+ };
+
+ let string = match String::from_utf8(output.stdout) {
+ Ok(string) => string,
+ Err(e) => {
+ let rustc = rustc.to_string_lossy();
+ eprintln!(
+ "Error: failed to parse output of `{} --version`: {}",
+ rustc, e,
+ );
+ process::exit(1);
+ }
+ };
+
+ let version = match rustc::parse(&string) {
+ Some(version) => format!("{:#?}\n", version),
+ None => {
+ eprintln!(
+ "Error: unexpected output from `rustc --version`: {:?}\n\n\
+ Please file an issue in https://github.com/dtolnay/rustversion",
+ string
+ );
+ process::exit(1);
+ }
+ };
+
+ let out_dir = env::var_os("OUT_DIR").expect("OUT_DIR not set");
+ let out_file = Path::new(&out_dir).join("version.rs");
+ fs::write(out_file, version).expect("failed to write version.rs");
+}
diff --git a/build/rustc.rs b/build/rustc.rs
new file mode 100644
index 0000000..723e6bd
--- /dev/null
+++ b/build/rustc.rs
@@ -0,0 +1,114 @@
+use self::Channel::*;
+use std::fmt::{self, Debug};
+
+#[cfg_attr(test, derive(PartialEq))]
+pub struct Version {
+ pub minor: u16,
+ pub patch: u16,
+ pub channel: Channel,
+}
+
+#[cfg_attr(test, derive(PartialEq))]
+pub enum Channel {
+ Stable,
+ Beta,
+ Nightly(Date),
+ Dev,
+}
+
+#[cfg_attr(test, derive(PartialEq))]
+pub struct Date {
+ pub year: u16,
+ pub month: u8,
+ pub day: u8,
+}
+
+pub fn parse(string: &str) -> Option<Version> {
+ let last_line = string.lines().last().unwrap_or(&string);
+ let mut words = last_line.trim().split(' ');
+
+ if words.next()? != "rustc" {
+ return None;
+ }
+
+ let mut version_channel = words.next()?.split('-');
+ let version = version_channel.next()?;
+ let channel = version_channel.next();
+
+ let mut digits = version.split('.');
+ let major = digits.next()?;
+ if major != "1" {
+ return None;
+ }
+ let minor = digits.next()?.parse().ok()?;
+ let patch = digits.next().unwrap_or("0").parse().ok()?;
+
+ let channel = match channel {
+ None => Stable,
+ Some(channel) if channel == "dev" => Dev,
+ Some(channel) if channel.starts_with("beta") => Beta,
+ Some(channel) if channel == "nightly" => match words.next() {
+ Some(hash) => {
+ if !hash.starts_with('(') {
+ return None;
+ }
+ let date = words.next()?;
+ if !date.ends_with(')') {
+ return None;
+ }
+ let mut date = date[..date.len() - 1].split('-');
+ let year = date.next()?.parse().ok()?;
+ let month = date.next()?.parse().ok()?;
+ let day = date.next()?.parse().ok()?;
+ match date.next() {
+ None => Nightly(Date { year, month, day }),
+ Some(_) => return None,
+ }
+ }
+ None => Dev,
+ },
+ Some(_) => return None,
+ };
+
+ Some(Version {
+ minor,
+ patch,
+ channel,
+ })
+}
+
+impl Debug for Version {
+ fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+ formatter
+ .debug_struct("crate::version::Version")
+ .field("minor", &self.minor)
+ .field("patch", &self.patch)
+ .field("channel", &self.channel)
+ .finish()
+ }
+}
+
+impl Debug for Channel {
+ fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+ match self {
+ Channel::Stable => formatter.write_str("crate::version::Channel::Stable"),
+ Channel::Beta => formatter.write_str("crate::version::Channel::Beta"),
+ Channel::Nightly(date) => formatter
+ .debug_tuple("crate::version::Channel::Nightly")
+ .field(date)
+ .finish(),
+ Channel::Dev => formatter.write_str("crate::version::Channel::Dev"),
+ }
+ }
+}
+
+impl Debug for Date {
+ fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+ formatter
+ .debug_struct("crate::date::Date")
+ .field("year", &self.year)
+ .field("month", &self.month)
+ .field("day", &self.day)
+ .finish()
+ }
+}
diff --git a/src/attr.rs b/src/attr.rs
new file mode 100644
index 0000000..6023d1e
--- /dev/null
+++ b/src/attr.rs
@@ -0,0 +1,35 @@
+use crate::error::{Error, Result};
+use crate::expr::{self, Expr};
+use crate::{iter, token};
+use proc_macro::{Span, TokenStream};
+
+pub struct Args {
+ pub condition: Expr,
+ pub then: Then,
+}
+
+pub enum Then {
+ Const(Span),
+ Attribute(TokenStream),
+}
+
+pub fn parse(input: TokenStream) -> Result<Args> {
+ let ref mut input = iter::new(input);
+ let condition = expr::parse(input)?;
+
+ token::parse_punct(input, ',')?;
+ if input.peek().is_none() {
+ return Err(Error::new(Span::call_site(), "expected one or more attrs"));
+ }
+
+ let const_span = token::parse_optional_keyword(input, "const");
+ let then = if let Some(const_span) = const_span {
+ token::parse_optional_punct(input, ',');
+ token::parse_end(input)?;
+ Then::Const(const_span)
+ } else {
+ Then::Attribute(input.collect())
+ };
+
+ Ok(Args { condition, then })
+}
diff --git a/src/bound.rs b/src/bound.rs
new file mode 100644
index 0000000..a667a5b
--- /dev/null
+++ b/src/bound.rs
@@ -0,0 +1,63 @@
+use crate::date::{self, Date};
+use crate::error::{Error, Result};
+use crate::iter::Iter;
+use crate::release::{self, Release};
+use crate::time;
+use crate::version::{Channel::*, Version};
+use proc_macro::{Group, TokenTree};
+use std::cmp::Ordering;
+
+pub enum Bound {
+ Nightly(Date),
+ Stable(Release),
+}
+
+pub fn parse(paren: Group, iter: Iter) -> Result<Bound> {
+ if let Some(TokenTree::Literal(literal)) = iter.peek() {
+ let repr = literal.to_string();
+ if repr.starts_with(|ch: char| ch.is_ascii_digit()) {
+ if repr.contains('.') {
+ return release::parse(paren, iter).map(Bound::Stable);
+ } else {
+ return date::parse(paren, iter).map(Bound::Nightly);
+ }
+ }
+ }
+ let msg = format!(
+ "expected rustc release number like 1.31, or nightly date like {}",
+ time::today(),
+ );
+ Err(Error::group(paren, msg))
+}
+
+impl PartialEq<Bound> for Version {
+ fn eq(&self, rhs: &Bound) -> bool {
+ match rhs {
+ Bound::Nightly(date) => match self.channel {
+ Stable | Beta | Dev => false,
+ Nightly(nightly) => nightly == *date,
+ },
+ Bound::Stable(release) => {
+ self.minor == release.minor
+ && release.patch.map_or(true, |patch| self.patch == patch)
+ }
+ }
+ }
+}
+
+impl PartialOrd<Bound> for Version {
+ fn partial_cmp(&self, rhs: &Bound) -> Option<Ordering> {
+ match rhs {
+ Bound::Nightly(date) => match self.channel {
+ Stable | Beta => Some(Ordering::Less),
+ Nightly(nightly) => Some(nightly.cmp(date)),
+ Dev => Some(Ordering::Greater),
+ },
+ Bound::Stable(release) => {
+ let version = (self.minor, self.patch);
+ let bound = (release.minor, release.patch.unwrap_or(0));
+ Some(version.cmp(&bound))
+ }
+ }
+ }
+}
diff --git a/src/constfn.rs b/src/constfn.rs
new file mode 100644
index 0000000..0e50c03
--- /dev/null
+++ b/src/constfn.rs
@@ -0,0 +1,58 @@
+use crate::error::{Error, Result};
+use proc_macro::{Ident, Span, TokenStream, TokenTree};
+use std::iter;
+
+#[derive(PartialOrd, PartialEq)]
+enum Qualifiers {
+ None,
+ Async,
+ Unsafe,
+ Extern,
+ Abi,
+}
+
+impl Qualifiers {
+ fn from_ident(ident: &Ident) -> Self {
+ match ident.to_string().as_str() {
+ "async" => Qualifiers::Async,
+ "unsafe" => Qualifiers::Unsafe,
+ "extern" => Qualifiers::Extern,
+ _ => Qualifiers::None,
+ }
+ }
+}
+
+pub(crate) fn insert_const(input: TokenStream, const_span: Span) -> Result<TokenStream> {
+ let ref mut input = crate::iter::new(input);
+ let mut out = TokenStream::new();
+ let mut qualifiers = Qualifiers::None;
+ let mut pending = Vec::new();
+
+ while let Some(token) = input.next() {
+ match token {
+ TokenTree::Ident(ref ident) if ident.to_string() == "fn" => {
+ let const_ident = Ident::new("const", const_span);
+ out.extend(iter::once(TokenTree::Ident(const_ident)));
+ out.extend(pending);
+ out.extend(iter::once(token));
+ out.extend(input);
+ return Ok(out);
+ }
+ TokenTree::Ident(ref ident) if Qualifiers::from_ident(ident) > qualifiers => {
+ qualifiers = Qualifiers::from_ident(ident);
+ pending.push(token);
+ }
+ TokenTree::Literal(_) if qualifiers == Qualifiers::Extern => {
+ qualifiers = Qualifiers::Abi;
+ pending.push(token);
+ }
+ _ => {
+ qualifiers = Qualifiers::None;
+ out.extend(pending.drain(..));
+ out.extend(iter::once(token));
+ }
+ }
+ }
+
+ Err(Error::new(const_span, "only allowed on a fn item"))
+}
diff --git a/src/date.rs b/src/date.rs
new file mode 100644
index 0000000..5cdb691
--- /dev/null
+++ b/src/date.rs
@@ -0,0 +1,50 @@
+use crate::error::{Error, Result};
+use crate::iter::Iter;
+use crate::{time, token};
+use proc_macro::Group;
+use std::fmt::{self, Display};
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Date {
+ pub year: u16,
+ pub month: u8,
+ pub day: u8,
+}
+
+impl Display for Date {
+ fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+ write!(
+ formatter,
+ "{:04}-{:02}-{:02}",
+ self.year, self.month, self.day,
+ )
+ }
+}
+
+pub fn parse(paren: Group, iter: Iter) -> Result<Date> {
+ try_parse(iter).map_err(|_| {
+ let msg = format!("expected nightly date, like {}", time::today());
+ Error::group(paren, msg)
+ })
+}
+
+fn try_parse(iter: Iter) -> Result<Date, ()> {
+ let year = token::parse_literal(iter).map_err(drop)?;
+ token::parse_punct(iter, '-').map_err(drop)?;
+ let month = token::parse_literal(iter).map_err(drop)?;
+ token::parse_punct(iter, '-').map_err(drop)?;
+ let day = token::parse_literal(iter).map_err(drop)?;
+
+ let year = year.to_string().parse::<u64>().map_err(drop)?;
+ let month = month.to_string().parse::<u64>().map_err(drop)?;
+ let day = day.to_string().parse::<u64>().map_err(drop)?;
+ if year >= 3000 || month > 12 || day > 31 {
+ return Err(());
+ }
+
+ Ok(Date {
+ year: year as u16,
+ month: month as u8,
+ day: day as u8,
+ })
+}
diff --git a/src/error.rs b/src/error.rs
new file mode 100644
index 0000000..a99625b
--- /dev/null
+++ b/src/error.rs
@@ -0,0 +1,56 @@
+use proc_macro::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
+use std::fmt::Display;
+use std::iter::FromIterator;
+
+pub type Result<T, E = Error> = std::result::Result<T, E>;
+
+pub struct Error {
+ begin: Span,
+ end: Span,
+ msg: String,
+}
+
+impl Error {
+ pub fn new(span: Span, msg: impl Display) -> Self {
+ Self::new2(span, span, msg)
+ }
+
+ pub fn new2(begin: Span, end: Span, msg: impl Display) -> Self {
+ Error {
+ begin,
+ end,
+ msg: msg.to_string(),
+ }
+ }
+
+ pub fn group(group: Group, msg: impl Display) -> Self {
+ let mut iter = group.stream().into_iter();
+ let delimiter = group.span();
+ let begin = iter.next().map_or(delimiter, |t| t.span());
+ let end = iter.last().map_or(begin, |t| t.span());
+ Self::new2(begin, end, msg)
+ }
+
+ pub fn into_compile_error(self) -> TokenStream {
+ // compile_error! { $msg }
+ TokenStream::from_iter(vec![
+ TokenTree::Ident(Ident::new("compile_error", self.begin)),
+ TokenTree::Punct({
+ let mut punct = Punct::new('!', Spacing::Alone);
+ punct.set_span(self.begin);
+ punct
+ }),
+ TokenTree::Group({
+ let mut group = Group::new(Delimiter::Brace, {
+ TokenStream::from_iter(vec![TokenTree::Literal({
+ let mut string = Literal::string(&self.msg);
+ string.set_span(self.end);
+ string
+ })])
+ });
+ group.set_span(self.end);
+ group
+ }),
+ ])
+ }
+}
diff --git a/src/expr.rs b/src/expr.rs
new file mode 100644
index 0000000..45ed7d2
--- /dev/null
+++ b/src/expr.rs
@@ -0,0 +1,163 @@
+use crate::bound::{self, Bound};
+use crate::date::{self, Date};
+use crate::error::{Error, Result};
+use crate::iter::{self, Iter};
+use crate::release::{self, Release};
+use crate::token;
+use crate::version::{Channel, Version};
+use proc_macro::{Ident, Span, TokenTree};
+
+pub enum Expr {
+ Stable,
+ Beta,
+ Nightly,
+ Date(Date),
+ Since(Bound),
+ Before(Bound),
+ Release(Release),
+ Not(Box<Expr>),
+ Any(Vec<Expr>),
+ All(Vec<Expr>),
+}
+
+impl Expr {
+ pub fn eval(&self, rustc: Version) -> bool {
+ use self::Expr::*;
+
+ match self {
+ Stable => rustc.channel == Channel::Stable,
+ Beta => rustc.channel == Channel::Beta,
+ Nightly => match rustc.channel {
+ Channel::Nightly(_) | Channel::Dev => true,
+ Channel::Stable | Channel::Beta => false,
+ },
+ Date(date) => match rustc.channel {
+ Channel::Nightly(rustc) => rustc == *date,
+ Channel::Stable | Channel::Beta | Channel::Dev => false,
+ },
+ Since(bound) => rustc >= *bound,
+ Before(bound) => rustc < *bound,
+ Release(release) => {
+ rustc.channel == Channel::Stable
+ && rustc.minor == release.minor
+ && release.patch.map_or(true, |patch| rustc.patch == patch)
+ }
+ Not(expr) => !expr.eval(rustc),
+ Any(exprs) => exprs.iter().any(|e| e.eval(rustc)),
+ All(exprs) => exprs.iter().all(|e| e.eval(rustc)),
+ }
+ }
+}
+
+pub fn parse(iter: Iter) -> Result<Expr> {
+ match &iter.next() {
+ Some(TokenTree::Ident(i)) if i.to_string() == "stable" => parse_stable(iter),
+ Some(TokenTree::Ident(i)) if i.to_string() == "beta" => Ok(Expr::Beta),
+ Some(TokenTree::Ident(i)) if i.to_string() == "nightly" => parse_nightly(iter),
+ Some(TokenTree::Ident(i)) if i.to_string() == "since" => parse_since(i, iter),
+ Some(TokenTree::Ident(i)) if i.to_string() == "before" => parse_before(i, iter),
+ Some(TokenTree::Ident(i)) if i.to_string() == "not" => parse_not(i, iter),
+ Some(TokenTree::Ident(i)) if i.to_string() == "any" => parse_any(i, iter),
+ Some(TokenTree::Ident(i)) if i.to_string() == "all" => parse_all(i, iter),
+ unexpected => {
+ let span = unexpected
+ .as_ref()
+ .map_or_else(Span::call_site, TokenTree::span);
+ Err(Error::new(span, "expected one of `stable`, `beta`, `nightly`, `since`, `before`, `not`, `any`, `all`"))
+ }
+ }
+}
+
+fn parse_nightly(iter: Iter) -> Result<Expr> {
+ let paren = match token::parse_optional_paren(iter) {
+ Some(group) => group,
+ None => return Ok(Expr::Nightly),
+ };
+
+ let ref mut inner = iter::new(paren.stream());
+ let date = date::parse(paren, inner)?;
+ token::parse_optional_punct(inner, ',');
+ token::parse_end(inner)?;
+
+ Ok(Expr::Date(date))
+}
+
+fn parse_stable(iter: Iter) -> Result<Expr> {
+ let paren = match token::parse_optional_paren(iter) {
+ Some(group) => group,
+ None => return Ok(Expr::Stable),
+ };
+
+ let ref mut inner = iter::new(paren.stream());
+ let release = release::parse(paren, inner)?;
+ token::parse_optional_punct(inner, ',');
+ token::parse_end(inner)?;
+
+ Ok(Expr::Release(release))
+}
+
+fn parse_since(introducer: &Ident, iter: Iter) -> Result<Expr> {
+ let paren = token::parse_paren(introducer, iter)?;
+
+ let ref mut inner = iter::new(paren.stream());
+ let bound = bound::parse(paren, inner)?;
+ token::parse_optional_punct(inner, ',');
+ token::parse_end(inner)?;
+
+ Ok(Expr::Since(bound))
+}
+
+fn parse_before(introducer: &Ident, iter: Iter) -> Result<Expr> {
+ let paren = token::parse_paren(introducer, iter)?;
+
+ let ref mut inner = iter::new(paren.stream());
+ let bound = bound::parse(paren, inner)?;
+ token::parse_optional_punct(inner, ',');
+ token::parse_end(inner)?;
+
+ Ok(Expr::Before(bound))
+}
+
+fn parse_not(introducer: &Ident, iter: Iter) -> Result<Expr> {
+ let paren = token::parse_paren(introducer, iter)?;
+
+ let ref mut inner = iter::new(paren.stream());
+ let expr = self::parse(inner)?;
+ token::parse_optional_punct(inner, ',');
+ token::parse_end(inner)?;
+
+ Ok(Expr::Not(Box::new(expr)))
+}
+
+fn parse_any(introducer: &Ident, iter: Iter) -> Result<Expr> {
+ let paren = token::parse_paren(introducer, iter)?;
+
+ let ref mut inner = iter::new(paren.stream());
+ let exprs = parse_comma_separated(inner)?;
+
+ Ok(Expr::Any(exprs.into_iter().collect()))
+}
+
+fn parse_all(introducer: &Ident, iter: Iter) -> Result<Expr> {
+ let paren = token::parse_paren(introducer, iter)?;
+
+ let ref mut inner = iter::new(paren.stream());
+ let exprs = parse_comma_separated(inner)?;
+
+ Ok(Expr::All(exprs.into_iter().collect()))
+}
+
+fn parse_comma_separated(iter: Iter) -> Result<Vec<Expr>> {
+ let mut exprs = Vec::new();
+
+ while iter.peek().is_some() {
+ let expr = self::parse(iter)?;
+ exprs.push(expr);
+ if iter.peek().is_none() {
+ break;
+ }
+ token::parse_punct(iter, ',')?;
+ }
+
+ Ok(exprs)
+}
diff --git a/src/iter.rs b/src/iter.rs
new file mode 100644
index 0000000..722013c
--- /dev/null
+++ b/src/iter.rs
@@ -0,0 +1,42 @@
+use proc_macro::{token_stream, Delimiter, TokenStream, TokenTree};
+
+pub type Iter<'a> = &'a mut IterImpl;
+
+pub struct IterImpl {
+ stack: Vec<token_stream::IntoIter>,
+ peeked: Option<TokenTree>,
+}
+
+pub fn new(tokens: TokenStream) -> IterImpl {
+ IterImpl {
+ stack: vec![tokens.into_iter()],
+ peeked: None,
+ }
+}
+
+impl IterImpl {
+ pub fn peek(&mut self) -> Option<&TokenTree> {
+ self.peeked = self.next();
+ self.peeked.as_ref()
+ }
+}
+
+impl Iterator for IterImpl {
+ type Item = TokenTree;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ if let Some(tt) = self.peeked.take() {
+ return Some(tt);
+ }
+ loop {
+ let top = self.stack.last_mut()?;
+ match top.next() {
+ None => drop(self.stack.pop()),
+ Some(TokenTree::Group(ref group)) if group.delimiter() == Delimiter::None => {
+ self.stack.push(group.stream().into_iter());
+ }
+ Some(tt) => return Some(tt),
+ }
+ }
+ }
+}
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..2614105
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,282 @@
+//! [![github]](https://github.com/dtolnay/rustversion) [![crates-io]](https://crates.io/crates/rustversion) [![docs-rs]](https://docs.rs/rustversion)
+//!
+//! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github
+//! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust
+//! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logoColor=white&logo=data:image/svg+xml;base64,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
+//!
+//! <br>
+//!
+//! This crate provides macros for conditional compilation according to rustc
+//! compiler version, analogous to [`#[cfg(...)]`][cfg] and
+//! [`#[cfg_attr(...)]`][cfg_attr].
+//!
+//! [cfg]: https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg-attribute
+//! [cfg_attr]: https://doc.rust-lang.org/reference/conditional-compilation.html#the-cfg_attr-attribute
+//!
+//! <br>
+//!
+//! # Selectors
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::stable]</code></b>
+//! —<br>
+//! True on any stable compiler.
+//! </p>
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::stable(1.34)]</code></b>
+//! —<br>
+//! True on exactly the specified stable compiler.
+//! </p>
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::beta]</code></b>
+//! —<br>
+//! True on any beta compiler.
+//! </p>
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::nightly]</code></b>
+//! —<br>
+//! True on any nightly compiler or dev build.
+//! </p>
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::nightly(2019-01-01)]</code></b>
+//! —<br>
+//! True on exactly one nightly.
+//! </p>
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::since(1.34)]</code></b>
+//! —<br>
+//! True on that stable release and any later compiler, including beta and
+//! nightly.
+//! </p>
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::since(2019-01-01)]</code></b>
+//! —<br>
+//! True on that nightly and all newer ones.
+//! </p>
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::before(</code></b><i>version or date</i><b><code>)]</code></b>
+//! —<br>
+//! Negative of <i>#[rustversion::since(...)]</i>.
+//! </p>
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::not(</code></b><i>selector</i><b><code>)]</code></b>
+//! —<br>
+//! Negative of any selector; for example <i>#[rustversion::not(nightly)]</i>.
+//! </p>
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::any(</code></b><i>selectors...</i><b><code>)]</code></b>
+//! —<br>
+//! True if any of the comma-separated selectors is true; for example
+//! <i>#[rustversion::any(stable, beta)]</i>.
+//! </p>
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::all(</code></b><i>selectors...</i><b><code>)]</code></b>
+//! —<br>
+//! True if all of the comma-separated selectors are true; for example
+//! <i>#[rustversion::all(since(1.31), before(1.34))]</i>.
+//! </p>
+//!
+//! - <p style="margin-left:50px;text-indent:-50px">
+//! <b><code>#[rustversion::attr(</code></b><i>selector</i><b><code>, </code></b><i>attribute</i><b><code>)]</code></b>
+//! —<br>
+//! For conditional inclusion of attributes; analogous to
+//! <code>cfg_attr</code>.
+//! </p>
+//!
+//! <br>
+//!
+//! # Use cases
+//!
+//! Providing additional trait impls as types are stabilized in the standard library
+//! without breaking compatibility with older compilers; in this case Pin\<P\>
+//! stabilized in [Rust 1.33][pin]:
+//!
+//! [pin]: https://blog.rust-lang.org/2019/02/28/Rust-1.33.0.html#pinning
+//!
+//! ```
+//! # trait MyTrait {}
+//! #
+//! #[rustversion::since(1.33)]
+//! use std::pin::Pin;
+//!
+//! #[rustversion::since(1.33)]
+//! impl<P: MyTrait> MyTrait for Pin<P> {
+//! /* ... */
+//! }
+//! ```
+//!
+//! Similar but for language features; the ability to control alignment greater than
+//! 1 of packed structs was stabilized in [Rust 1.33][packed].
+//!
+//! [packed]: https://github.com/rust-lang/rust/blob/master/RELEASES.md#version-1330-2019-02-28
+//!
+//! ```
+//! #[rustversion::attr(before(1.33), repr(packed))]
+//! #[rustversion::attr(since(1.33), repr(packed(2)))]
+//! struct Six(i16, i32);
+//!
+//! fn main() {
+//! println!("{}", std::mem::align_of::<Six>());
+//! }
+//! ```
+//!
+//! Augmenting code with `const` as const impls are stabilized in the standard
+//! library. This use of `const` as an attribute is recognized as a special case
+//! by the rustversion::attr macro.
+//!
+//! ```
+//! use std::time::Duration;
+//!
+//! #[rustversion::attr(since(1.32), const)]
+//! fn duration_as_days(dur: Duration) -> u64 {
+//! dur.as_secs() / 60 / 60 / 24
+//! }
+//! ```
+//!
+//! <br>
+
+extern crate proc_macro;
+
+mod attr;
+mod bound;
+mod constfn;
+mod date;
+mod error;
+mod expr;
+mod iter;
+mod release;
+mod time;
+mod token;
+mod version;
+
+use crate::attr::Then;
+use crate::error::{Error, Result};
+use crate::version::Version;
+use proc_macro::{Delimiter, Group, Ident, Punct, Spacing, Span, TokenStream, TokenTree};
+use std::iter::FromIterator;
+
+const RUSTVERSION: Version = include!(concat!(env!("OUT_DIR"), "/version.rs"));
+
+#[proc_macro_attribute]
+pub fn stable(args: TokenStream, input: TokenStream) -> TokenStream {
+ cfg("stable", args, input)
+}
+
+#[proc_macro_attribute]
+pub fn beta(args: TokenStream, input: TokenStream) -> TokenStream {
+ cfg("beta", args, input)
+}
+
+#[proc_macro_attribute]
+pub fn nightly(args: TokenStream, input: TokenStream) -> TokenStream {
+ cfg("nightly", args, input)
+}
+
+#[proc_macro_attribute]
+pub fn since(args: TokenStream, input: TokenStream) -> TokenStream {
+ cfg("since", args, input)
+}
+
+#[proc_macro_attribute]
+pub fn before(args: TokenStream, input: TokenStream) -> TokenStream {
+ cfg("before", args, input)
+}
+
+#[proc_macro_attribute]
+pub fn not(args: TokenStream, input: TokenStream) -> TokenStream {
+ cfg("not", args, input)
+}
+
+#[proc_macro_attribute]
+pub fn any(args: TokenStream, input: TokenStream) -> TokenStream {
+ cfg("any", args, input)
+}
+
+#[proc_macro_attribute]
+pub fn all(args: TokenStream, input: TokenStream) -> TokenStream {
+ cfg("all", args, input)
+}
+
+fn cfg(introducer: &str, args: TokenStream, input: TokenStream) -> TokenStream {
+ try_cfg(introducer, args, input).unwrap_or_else(Error::into_compile_error)
+}
+
+fn try_cfg(introducer: &str, args: TokenStream, input: TokenStream) -> Result<TokenStream> {
+ let introducer = Ident::new(introducer, Span::call_site());
+
+ let mut full_args = TokenStream::from(TokenTree::Ident(introducer));
+ if !args.is_empty() {
+ full_args.extend(std::iter::once(TokenTree::Group(Group::new(
+ Delimiter::Parenthesis,
+ args,
+ ))));
+ }
+
+ let ref mut full_args = iter::new(full_args);
+ let expr = expr::parse(full_args)?;
+ token::parse_end(full_args)?;
+
+ if expr.eval(RUSTVERSION) {
+ Ok(input)
+ } else {
+ Ok(TokenStream::new())
+ }
+}
+
+#[proc_macro_attribute]
+pub fn attr(args: TokenStream, input: TokenStream) -> TokenStream {
+ attr::parse(args)
+ .and_then(|args| try_attr(args, input))
+ .unwrap_or_else(Error::into_compile_error)
+}
+
+fn try_attr(args: attr::Args, input: TokenStream) -> Result<TokenStream> {
+ if !args.condition.eval(RUSTVERSION) {
+ return Ok(input);
+ }
+
+ match args.then {
+ Then::Const(const_token) => constfn::insert_const(input, const_token),
+ Then::Attribute(then) => {
+ // #[cfg_attr(all(), #then)]
+ Ok(TokenStream::from_iter(
+ vec![
+ TokenTree::Punct(Punct::new('#', Spacing::Alone)),
+ TokenTree::Group(Group::new(
+ Delimiter::Bracket,
+ TokenStream::from_iter(vec![
+ TokenTree::Ident(Ident::new("cfg_attr", Span::call_site())),
+ TokenTree::Group(Group::new(
+ Delimiter::Parenthesis,
+ TokenStream::from_iter(
+ vec![
+ TokenTree::Ident(Ident::new("all", Span::call_site())),
+ TokenTree::Group(Group::new(
+ Delimiter::Parenthesis,
+ TokenStream::new(),
+ )),
+ TokenTree::Punct(Punct::new(',', Spacing::Alone)),
+ ]
+ .into_iter()
+ .chain(then),
+ ),
+ )),
+ ]),
+ )),
+ ]
+ .into_iter()
+ .chain(input),
+ ))
+ }
+ }
+}
diff --git a/src/release.rs b/src/release.rs
new file mode 100644
index 0000000..3f421c6
--- /dev/null
+++ b/src/release.rs
@@ -0,0 +1,34 @@
+use crate::error::{Error, Result};
+use crate::iter::Iter;
+use crate::token;
+use proc_macro::Group;
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Release {
+ pub minor: u16,
+ pub patch: Option<u16>,
+}
+
+pub fn parse(paren: Group, iter: Iter) -> Result<Release> {
+ try_parse(iter).map_err(|_| Error::group(paren, "expected rustc release number, like 1.31"))
+}
+
+fn try_parse(iter: Iter) -> Result<Release, ()> {
+ let major_minor = token::parse_literal(iter).map_err(drop)?;
+ let string = major_minor.to_string();
+
+ if !string.starts_with("1.") {
+ return Err(());
+ }
+
+ let minor: u16 = string[2..].parse().map_err(drop)?;
+
+ let patch = if token::parse_optional_punct(iter, '.').is_some() {
+ let int = token::parse_literal(iter).map_err(drop)?;
+ Some(int.to_string().parse().map_err(drop)?)
+ } else {
+ None
+ };
+
+ Ok(Release { minor, patch })
+}
diff --git a/src/time.rs b/src/time.rs
new file mode 100644
index 0000000..1e6dd90
--- /dev/null
+++ b/src/time.rs
@@ -0,0 +1,44 @@
+use crate::date::Date;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+// Timestamp of 2016-03-01 00:00:00 in UTC.
+const BASE: u64 = 1456790400;
+const BASE_YEAR: u16 = 2016;
+const BASE_MONTH: u8 = 3;
+
+// Days between leap days.
+const CYCLE: u64 = 365 * 4 + 1;
+
+const DAYS_BY_MONTH: [u8; 12] = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
+
+pub fn today() -> Date {
+ let default = Date {
+ year: 2019,
+ month: 1,
+ day: 1,
+ };
+ try_today().unwrap_or(default)
+}
+
+fn try_today() -> Option<Date> {
+ let now = SystemTime::now();
+ let since_epoch = now.duration_since(UNIX_EPOCH).ok()?;
+ let secs = since_epoch.as_secs();
+
+ let approx_days = secs.checked_sub(BASE)? / 60 / 60 / 24;
+ let cycle = approx_days / CYCLE;
+ let mut rem = approx_days % CYCLE;
+
+ let mut year = BASE_YEAR + cycle as u16 * 4;
+ let mut month = BASE_MONTH;
+ loop {
+ let days_in_month = DAYS_BY_MONTH[month as usize - 1];
+ if rem < days_in_month as u64 {
+ let day = rem as u8 + 1;
+ return Some(Date { year, month, day });
+ }
+ rem -= days_in_month as u64;
+ year += (month == 12) as u16;
+ month = month % 12 + 1;
+ }
+}
diff --git a/src/token.rs b/src/token.rs
new file mode 100644
index 0000000..ebb6f1c
--- /dev/null
+++ b/src/token.rs
@@ -0,0 +1,78 @@
+use crate::error::{Error, Result};
+use crate::iter::Iter;
+use proc_macro::{Delimiter, Group, Ident, Literal, Span, TokenTree};
+
+pub fn parse_punct(iter: Iter, ch: char) -> Result<()> {
+ match iter.next() {
+ Some(TokenTree::Punct(ref punct)) if punct.as_char() == ch => Ok(()),
+ unexpected => {
+ let span = unexpected
+ .as_ref()
+ .map_or_else(Span::call_site, TokenTree::span);
+ Err(Error::new(span, format!("expected `{}`", ch)))
+ }
+ }
+}
+
+pub fn parse_optional_punct(iter: Iter, ch: char) -> Option<()> {
+ match iter.peek() {
+ Some(TokenTree::Punct(punct)) if punct.as_char() == ch => iter.next().map(drop),
+ _ => None,
+ }
+}
+
+pub fn parse_optional_keyword(iter: Iter, keyword: &str) -> Option<Span> {
+ match iter.peek() {
+ Some(TokenTree::Ident(ident)) if ident.to_string() == keyword => {
+ Some(iter.next().unwrap().span())
+ }
+ _ => None,
+ }
+}
+
+pub fn parse_literal(iter: Iter) -> Result<Literal> {
+ match iter.next() {
+ Some(TokenTree::Literal(literal)) => Ok(literal),
+ unexpected => {
+ let span = unexpected
+ .as_ref()
+ .map_or_else(Span::call_site, TokenTree::span);
+ Err(Error::new(span, "expected literal"))
+ }
+ }
+}
+
+pub fn parse_paren(introducer: &Ident, iter: Iter) -> Result<Group> {
+ match iter.peek() {
+ Some(TokenTree::Group(group)) if group.delimiter() == Delimiter::Parenthesis => {
+ match iter.next() {
+ Some(TokenTree::Group(group)) => Ok(group),
+ _ => unreachable!(),
+ }
+ }
+ Some(unexpected) => Err(Error::new(unexpected.span(), "expected `(`")),
+ None => Err(Error::new(
+ introducer.span(),
+ format!("expected `(` after `{}`", introducer),
+ )),
+ }
+}
+
+pub fn parse_optional_paren(iter: Iter) -> Option<Group> {
+ match iter.peek() {
+ Some(TokenTree::Group(group)) if group.delimiter() == Delimiter::Parenthesis => {
+ match iter.next() {
+ Some(TokenTree::Group(group)) => Some(group),
+ _ => unreachable!(),
+ }
+ }
+ _ => None,
+ }
+}
+
+pub fn parse_end(iter: Iter) -> Result<()> {
+ match iter.next() {
+ None => Ok(()),
+ Some(unexpected) => Err(Error::new(unexpected.span(), "unexpected token")),
+ }
+}
diff --git a/src/version.rs b/src/version.rs
new file mode 100644
index 0000000..f4a69f5
--- /dev/null
+++ b/src/version.rs
@@ -0,0 +1,18 @@
+#![allow(dead_code)]
+
+use crate::date::Date;
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub struct Version {
+ pub minor: u16,
+ pub patch: u16,
+ pub channel: Channel,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum Channel {
+ Stable,
+ Beta,
+ Nightly(Date),
+ Dev,
+}
diff --git a/tests/compiletest.rs b/tests/compiletest.rs
new file mode 100644
index 0000000..f9aea23
--- /dev/null
+++ b/tests/compiletest.rs
@@ -0,0 +1,6 @@
+#[rustversion::attr(not(nightly), ignore)]
+#[test]
+fn ui() {
+ let t = trybuild::TestCases::new();
+ t.compile_fail("tests/ui/*.rs");
+}
diff --git a/tests/test_const.rs b/tests/test_const.rs
new file mode 100644
index 0000000..1765c95
--- /dev/null
+++ b/tests/test_const.rs
@@ -0,0 +1,37 @@
+#[rustversion::attr(all(), const)]
+fn _basic() {}
+const _BASIC: () = _basic();
+
+#[rustversion::attr(all(), const)]
+unsafe fn _unsafe() {}
+const _UNSAFE: () = unsafe { _unsafe() };
+
+macro_rules! item {
+ ($i:item) => {
+ #[rustversion::attr(all(), const)]
+ $i
+ };
+}
+
+item! {fn _item() {}}
+const _ITEM: () = _item();
+
+macro_rules! ident {
+ ($fn:ident) => {
+ #[rustversion::attr(all(), const)]
+ $fn _ident() {}
+ };
+}
+
+ident! {fn}
+const _IDENT: () = _ident();
+
+#[rustversion::attr(all(), const)]
+/// doc
+fn _doc_below() {}
+const _DOC_BELOW: () = _doc_below();
+
+/// doc
+#[rustversion::attr(all(), const)]
+fn _doc_above() {}
+const _DOC_ABOVE: () = _doc_above();
diff --git a/tests/test_eval.rs b/tests/test_eval.rs
new file mode 100644
index 0000000..c044e85
--- /dev/null
+++ b/tests/test_eval.rs
@@ -0,0 +1,20 @@
+#[rustversion::any(
+ stable,
+ stable(1.34),
+ stable(1.34.0),
+ beta,
+ nightly,
+ nightly(2020-02-25),
+ since(1.34),
+ since(2020-02-25),
+ before(1.34),
+ before(2020-02-25),
+ not(nightly),
+ all(stable, beta, nightly),
+)]
+fn success() {}
+
+#[test]
+fn test() {
+ success();
+}
diff --git a/tests/test_parse.rs b/tests/test_parse.rs
new file mode 100644
index 0000000..843bd73
--- /dev/null
+++ b/tests/test_parse.rs
@@ -0,0 +1,84 @@
+include!("../build/rustc.rs");
+
+#[test]
+fn test_parse() {
+ let cases = &[
+ (
+ "rustc 1.0.0 (a59de37e9 2015-05-13) (built 2015-05-14)",
+ Version {
+ minor: 0,
+ patch: 0,
+ channel: Stable,
+ },
+ ),
+ (
+ "rustc 1.18.0",
+ Version {
+ minor: 18,
+ patch: 0,
+ channel: Stable,
+ },
+ ),
+ (
+ "rustc 1.24.1 (d3ae9a9e0 2018-02-27)",
+ Version {
+ minor: 24,
+ patch: 1,
+ channel: Stable,
+ },
+ ),
+ (
+ "rustc 1.35.0-beta.3 (c13114dc8 2019-04-27)",
+ Version {
+ minor: 35,
+ patch: 0,
+ channel: Beta,
+ },
+ ),
+ (
+ "rustc 1.36.0-nightly (938d4ffe1 2019-04-27)",
+ Version {
+ minor: 36,
+ patch: 0,
+ channel: Nightly(Date {
+ year: 2019,
+ month: 4,
+ day: 27,
+ }),
+ },
+ ),
+ (
+ "rustc 1.36.0-dev",
+ Version {
+ minor: 36,
+ patch: 0,
+ channel: Dev,
+ },
+ ),
+ (
+ "rustc 1.36.0-nightly",
+ Version {
+ minor: 36,
+ patch: 0,
+ channel: Dev,
+ },
+ ),
+ (
+ "warning: invalid logging spec 'warning', ignoring it
+ rustc 1.30.0-nightly (3bc2ca7e4 2018-09-20)",
+ Version {
+ minor: 30,
+ patch: 0,
+ channel: Nightly(Date {
+ year: 2018,
+ month: 9,
+ day: 20,
+ }),
+ },
+ ),
+ ];
+
+ for (string, expected) in cases {
+ assert_eq!(parse(string).unwrap(), *expected);
+ }
+}
diff --git a/tests/ui/bad-bound.rs b/tests/ui/bad-bound.rs
new file mode 100644
index 0000000..add8792
--- /dev/null
+++ b/tests/ui/bad-bound.rs
@@ -0,0 +1,7 @@
+#[rustversion::since(stable)]
+struct S;
+
+#[rustversion::any(since(stable))]
+struct S;
+
+fn main() {}
diff --git a/tests/ui/bad-bound.stderr b/tests/ui/bad-bound.stderr
new file mode 100644
index 0000000..f8c498c
--- /dev/null
+++ b/tests/ui/bad-bound.stderr
@@ -0,0 +1,11 @@
+error: expected rustc release number like 1.31, or nightly date like 2020-10-26
+ --> $DIR/bad-bound.rs:1:22
+ |
+1 | #[rustversion::since(stable)]
+ | ^^^^^^
+
+error: expected rustc release number like 1.31, or nightly date like 2020-10-26
+ --> $DIR/bad-bound.rs:4:26
+ |
+4 | #[rustversion::any(since(stable))]
+ | ^^^^^^
diff --git a/tests/ui/bad-date.rs b/tests/ui/bad-date.rs
new file mode 100644
index 0000000..0984625
--- /dev/null
+++ b/tests/ui/bad-date.rs
@@ -0,0 +1,7 @@
+#[rustversion::nightly(stable)]
+struct S;
+
+#[rustversion::any(nightly(stable))]
+struct S;
+
+fn main() {}
diff --git a/tests/ui/bad-date.stderr b/tests/ui/bad-date.stderr
new file mode 100644
index 0000000..734d788
--- /dev/null
+++ b/tests/ui/bad-date.stderr
@@ -0,0 +1,11 @@
+error: expected nightly date, like 2020-10-26
+ --> $DIR/bad-date.rs:1:24
+ |
+1 | #[rustversion::nightly(stable)]
+ | ^^^^^^
+
+error: expected nightly date, like 2020-10-26
+ --> $DIR/bad-date.rs:4:28
+ |
+4 | #[rustversion::any(nightly(stable))]
+ | ^^^^^^
diff --git a/tests/ui/bad-not.rs b/tests/ui/bad-not.rs
new file mode 100644
index 0000000..058f340
--- /dev/null
+++ b/tests/ui/bad-not.rs
@@ -0,0 +1,7 @@
+#[rustversion::any(not)]
+struct S;
+
+#[rustversion::any(not, not)]
+struct S;
+
+fn main() {}
diff --git a/tests/ui/bad-not.stderr b/tests/ui/bad-not.stderr
new file mode 100644
index 0000000..bfe239b
--- /dev/null
+++ b/tests/ui/bad-not.stderr
@@ -0,0 +1,11 @@
+error: expected `(` after `not`
+ --> $DIR/bad-not.rs:1:20
+ |
+1 | #[rustversion::any(not)]
+ | ^^^
+
+error: expected `(`
+ --> $DIR/bad-not.rs:4:23
+ |
+4 | #[rustversion::any(not, not)]
+ | ^
diff --git a/tests/ui/bad-version.rs b/tests/ui/bad-version.rs
new file mode 100644
index 0000000..1fe8dba
--- /dev/null
+++ b/tests/ui/bad-version.rs
@@ -0,0 +1,7 @@
+#[rustversion::stable(nightly)]
+struct S;
+
+#[rustversion::any(stable(nightly))]
+struct S;
+
+fn main() {}
diff --git a/tests/ui/bad-version.stderr b/tests/ui/bad-version.stderr
new file mode 100644
index 0000000..5f7a01f
--- /dev/null
+++ b/tests/ui/bad-version.stderr
@@ -0,0 +1,11 @@
+error: expected rustc release number, like 1.31
+ --> $DIR/bad-version.rs:1:23
+ |
+1 | #[rustversion::stable(nightly)]
+ | ^^^^^^^
+
+error: expected rustc release number, like 1.31
+ --> $DIR/bad-version.rs:4:27
+ |
+4 | #[rustversion::any(stable(nightly))]
+ | ^^^^^^^
diff --git a/tests/ui/const-not-fn.rs b/tests/ui/const-not-fn.rs
new file mode 100644
index 0000000..215df7d
--- /dev/null
+++ b/tests/ui/const-not-fn.rs
@@ -0,0 +1,4 @@
+#[rustversion::attr(all(), const)]
+pub struct S;
+
+fn main() {}
diff --git a/tests/ui/const-not-fn.stderr b/tests/ui/const-not-fn.stderr
new file mode 100644
index 0000000..7371ff2
--- /dev/null
+++ b/tests/ui/const-not-fn.stderr
@@ -0,0 +1,5 @@
+error: only allowed on a fn item
+ --> $DIR/const-not-fn.rs:1:28
+ |
+1 | #[rustversion::attr(all(), const)]
+ | ^^^^^
