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			296 lines
		
	
	
	
		
			9 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			296 lines
		
	
	
	
		
			9 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! Contains code for selecting features
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#![deny(unused_extern_crates)]
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#![deny(clippy::missing_docs_in_private_items)]
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#![allow(deprecated)]
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use std::cmp::Ordering;
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use std::io;
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use std::str::FromStr;
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/// This macro defines the [`RustTarget`] and [`RustFeatures`] types.
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macro_rules! define_rust_targets {
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    (
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        Nightly => {$($nightly_feature:ident $(: #$issue:literal)?),* $(,)?} $(,)?
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        $(
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            $(#[$attrs:meta])*
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            $variant:ident($minor:literal) => {$($feature:ident $(: #$pull:literal)?),* $(,)?},
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        )*
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        $(,)?
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    ) => {
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        /// Represents the version of the Rust language to target.
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        ///
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        /// To support a beta release, use the corresponding stable release.
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        ///
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        /// This enum will have more variants added as necessary.
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        #[allow(non_camel_case_types)]
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        #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
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        pub enum RustTarget {
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            /// Rust Nightly
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            $(#[doc = concat!(
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                "- [`", stringify!($nightly_feature), "`]",
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                "(", $("https://github.com/rust-lang/rust/pull/", stringify!($issue),)* ")",
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            )])*
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            Nightly,
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            $(
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                #[doc = concat!("Rust 1.", stringify!($minor))]
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                $(#[doc = concat!(
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                    "- [`", stringify!($feature), "`]",
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                    "(", $("https://github.com/rust-lang/rust/pull/", stringify!($pull),)* ")",
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                )])*
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                $(#[$attrs])*
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                $variant,
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            )*
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        }
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        impl RustTarget {
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            fn minor(self) -> Option<u64> {
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                match self {
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                    $( Self::$variant => Some($minor),)*
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                    Self::Nightly => None
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                }
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            }
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            const fn stable_releases() -> [(Self, u64); [$($minor,)*].len()] {
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                [$((Self::$variant, $minor),)*]
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            }
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        }
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        #[cfg(feature = "__cli")]
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        /// Strings of allowed `RustTarget` values
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        pub const RUST_TARGET_STRINGS: &[&str] = &[$(concat!("1.", stringify!($minor)),)*];
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        #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
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        pub(crate) struct RustFeatures {
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            $($(pub(crate) $feature: bool,)*)*
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            $(pub(crate) $nightly_feature: bool,)*
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        }
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        impl From<RustTarget> for RustFeatures {
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            fn from(target: RustTarget) -> Self {
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                if target == RustTarget::Nightly {
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                    return Self {
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                        $($($feature: true,)*)*
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                        $($nightly_feature: true,)*
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                    };
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                }
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                let mut features = Self {
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                    $($($feature: false,)*)*
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                    $($nightly_feature: false,)*
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                };
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                $(if target >= RustTarget::$variant {
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                    $(features.$feature = true;)*
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                })*
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                features
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            }
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        }
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    };
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}
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// NOTE: When adding or removing features here, make sure to add the stabilization PR
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// number for the feature if it has been stabilized or the tracking issue number if the feature is
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// not stable.
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define_rust_targets! {
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    Nightly => {
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        vectorcall_abi,
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    },
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    Stable_1_73(73) => { thiscall_abi: #42202 },
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    Stable_1_71(71) => { c_unwind_abi: #106075 },
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    Stable_1_68(68) => { abi_efiapi: #105795 },
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    Stable_1_64(64) => { core_ffi_c: #94503 },
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    Stable_1_59(59) => { const_cstr: #54745 },
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    Stable_1_47(47) => { larger_arrays: #74060 },
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    Stable_1_40(40) => { non_exhaustive: #44109 },
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    Stable_1_36(36) => { maybe_uninit: #60445 },
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    Stable_1_33(33) => { repr_packed_n: #57049 },
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    #[deprecated]
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    Stable_1_30(30) => {
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        core_ffi_c_void: #53910,
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        min_const_fn: #54835,
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    },
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    #[deprecated]
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    Stable_1_28(28) => { repr_transparent: #51562 },
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    #[deprecated]
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    Stable_1_27(27) => { must_use_function: #48925 },
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    #[deprecated]
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    Stable_1_26(26) => { i128_and_u128: #49101 },
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    #[deprecated]
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    Stable_1_25(25) => { repr_align: #47006 },
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    #[deprecated]
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    Stable_1_21(21) => { builtin_clone_impls: #43690 },
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    #[deprecated]
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    Stable_1_20(20) => { associated_const: #42809 },
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    #[deprecated]
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    Stable_1_19(19) => { untagged_union: #42068 },
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    #[deprecated]
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    Stable_1_17(17) => { static_lifetime_elision: #39265 },
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    #[deprecated]
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    Stable_1_0(0) => {},
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}
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/// Latest stable release of Rust
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pub const LATEST_STABLE_RUST: RustTarget = {
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    // FIXME: replace all this code by
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    // ```
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    // RustTarget::stable_releases()
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    //     .into_iter()
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    //     .max_by_key(|(_, m)| m)
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    //     .map(|(t, _)| t)
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    //     .unwrap_or(RustTarget::Nightly)
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    // ```
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    // once those operations can be used in constants.
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    let targets = RustTarget::stable_releases();
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    let mut i = 0;
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    let mut latest_target = None;
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    let mut latest_minor = 0;
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    while i < targets.len() {
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        let (target, minor) = targets[i];
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        if latest_minor < minor {
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            latest_minor = minor;
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            latest_target = Some(target);
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        }
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        i += 1;
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    }
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    match latest_target {
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        Some(target) => target,
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        None => unreachable!(),
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    }
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};
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impl Default for RustTarget {
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    fn default() -> Self {
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        LATEST_STABLE_RUST
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    }
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}
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impl PartialOrd for RustTarget {
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    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
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        Some(self.cmp(other))
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    }
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}
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impl Ord for RustTarget {
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    fn cmp(&self, other: &Self) -> Ordering {
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        match (self.minor(), other.minor()) {
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            (Some(a), Some(b)) => a.cmp(&b),
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            (Some(_), None) => Ordering::Less,
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            (None, Some(_)) => Ordering::Greater,
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            (None, None) => Ordering::Equal,
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        }
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    }
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}
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impl FromStr for RustTarget {
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    type Err = io::Error;
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    fn from_str(s: &str) -> Result<Self, Self::Err> {
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        if s == "nightly" {
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            return Ok(Self::Nightly);
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        }
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        if let Some(("1", str_minor)) = s.split_once('.') {
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            if let Ok(minor) = str_minor.parse::<u64>() {
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                for (target, target_minor) in Self::stable_releases() {
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                    if minor == target_minor {
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                        return Ok(target);
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                    }
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                }
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            }
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        }
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        Err(io::Error::new(
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            io::ErrorKind::InvalidInput,
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            "Got an invalid Rust target. Accepted values are of the form \"1.71\" or \"nightly\"."
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        ))
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    }
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}
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impl std::fmt::Display for RustTarget {
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    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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        match self.minor() {
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            Some(minor) => write!(f, "1.{}", minor),
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            None => "nightly".fmt(f),
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        }
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    }
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}
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impl Default for RustFeatures {
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    fn default() -> Self {
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        RustTarget::default().into()
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    }
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}
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#[cfg(test)]
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mod test {
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    #![allow(unused_imports)]
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    use super::*;
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    #[test]
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    fn target_features() {
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        let f_1_0 = RustFeatures::from(RustTarget::Stable_1_0);
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        assert!(
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            !f_1_0.static_lifetime_elision &&
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                !f_1_0.core_ffi_c_void &&
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                !f_1_0.untagged_union &&
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                !f_1_0.associated_const &&
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                !f_1_0.builtin_clone_impls &&
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                !f_1_0.repr_align &&
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                !f_1_0.thiscall_abi &&
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                !f_1_0.vectorcall_abi
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        );
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        let f_1_21 = RustFeatures::from(RustTarget::Stable_1_21);
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        assert!(
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            f_1_21.static_lifetime_elision &&
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                !f_1_21.core_ffi_c_void &&
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                f_1_21.untagged_union &&
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                f_1_21.associated_const &&
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                f_1_21.builtin_clone_impls &&
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                !f_1_21.repr_align &&
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                !f_1_21.thiscall_abi &&
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                !f_1_21.vectorcall_abi
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        );
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        let features = RustFeatures::from(RustTarget::Stable_1_71);
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        assert!(
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            features.c_unwind_abi &&
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                features.abi_efiapi &&
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                !features.thiscall_abi
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        );
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        let f_nightly = RustFeatures::from(RustTarget::Nightly);
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        assert!(
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            f_nightly.static_lifetime_elision &&
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                f_nightly.core_ffi_c_void &&
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                f_nightly.untagged_union &&
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                f_nightly.associated_const &&
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                f_nightly.builtin_clone_impls &&
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                f_nightly.maybe_uninit &&
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                f_nightly.repr_align &&
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                f_nightly.thiscall_abi &&
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                f_nightly.vectorcall_abi
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        );
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    }
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    fn test_target(target_str: &str, target: RustTarget) {
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        let target_string = target.to_string();
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        assert_eq!(target_str, target_string);
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        assert_eq!(target, RustTarget::from_str(target_str).unwrap());
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    }
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    #[test]
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    fn str_to_target() {
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        test_target("1.0", RustTarget::Stable_1_0);
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        test_target("1.17", RustTarget::Stable_1_17);
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        test_target("1.19", RustTarget::Stable_1_19);
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        test_target("1.21", RustTarget::Stable_1_21);
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        test_target("1.25", RustTarget::Stable_1_25);
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        test_target("1.71", RustTarget::Stable_1_71);
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        test_target("nightly", RustTarget::Nightly);
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    }
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}
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