mirror of
https://gitee.com/openharmony/third_party_rust_syn
synced 2024-12-04 06:01:18 +00:00
c6ce512015
This follows through on the comments on the __TestExhaustive variants
promising that their purpose will be substituted with a deny(reachable)
rustc lint once one is available.
That lint is now landing as non_exhaustive_omitted_patterns in Rust 1.57.
The correct way to use it for checking exhaustivity of a match is:
match expr {
Expr::Array(e) => {...}
Expr::Assign(e) => {...}
...
Expr::Yield(e) => {...}
#[cfg_attr(test, deny(non_exhaustive_omitted_patterns))]
_ => { /* some sane fallback */ }
}
52 lines
1.4 KiB
Rust
52 lines
1.4 KiB
Rust
use std::env;
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use std::process::Command;
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use std::str;
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// The rustc-cfg strings below are *not* public API. Please let us know by
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// opening a GitHub issue if your build environment requires some way to enable
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// these cfgs other than by executing our build script.
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fn main() {
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let compiler = match rustc_version() {
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Some(compiler) => compiler,
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None => return,
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};
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if compiler.minor < 36 {
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println!("cargo:rustc-cfg=syn_omit_await_from_token_macro");
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}
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if compiler.minor < 39 {
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println!("cargo:rustc-cfg=syn_no_const_vec_new");
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}
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if compiler.minor < 40 {
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println!("cargo:rustc-cfg=syn_no_non_exhaustive");
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}
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if compiler.minor < 56 {
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println!("cargo:rustc-cfg=syn_no_negative_literal_parse");
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}
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if !compiler.nightly {
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println!("cargo:rustc-cfg=syn_disable_nightly_tests");
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}
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}
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struct Compiler {
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minor: u32,
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nightly: bool,
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}
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fn rustc_version() -> Option<Compiler> {
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let rustc = env::var_os("RUSTC")?;
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let output = Command::new(rustc).arg("--version").output().ok()?;
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let version = str::from_utf8(&output.stdout).ok()?;
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let mut pieces = version.split('.');
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if pieces.next() != Some("rustc 1") {
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return None;
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}
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let minor = pieces.next()?.parse().ok()?;
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let nightly = version.contains("nightly") || version.ends_with("-dev");
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Some(Compiler { minor, nightly })
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}
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