rename rustc_attr to rustc_attr_parsing and create rustc_attr_data_structures

compiler/rustc_attr_data_structures/src/stability.rs

@@ -0,0 +1,200 @@
+use std::num::NonZero;
+
+use rustc_macros::{Decodable, Encodable, HashStable_Generic};
+use rustc_span::{Symbol, sym};
+
+use crate::RustcVersion;
+
+/// The version placeholder that recently stabilized features contain inside the
+/// `since` field of the `#[stable]` attribute.
+///
+/// For more, see [this pull request](https://github.com/rust-lang/rust/pull/100591).
+pub const VERSION_PLACEHOLDER: &str = "CURRENT_RUSTC_VERSION";
+
+/// Represents the following attributes:
+///
+/// - `#[stable]`
+/// - `#[unstable]`
+#[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(HashStable_Generic)]
+pub struct Stability {
+    pub level: StabilityLevel,
+    pub feature: Symbol,
+}
+
+impl Stability {
+    pub fn is_unstable(&self) -> bool {
+        self.level.is_unstable()
+    }
+
+    pub fn is_stable(&self) -> bool {
+        self.level.is_stable()
+    }
+
+    pub fn stable_since(&self) -> Option<StableSince> {
+        self.level.stable_since()
+    }
+}
+
+/// Represents the `#[rustc_const_unstable]` and `#[rustc_const_stable]` attributes.
+#[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(HashStable_Generic)]
+pub struct ConstStability {
+    pub level: StabilityLevel,
+    pub feature: Symbol,
+    /// whether the function has a `#[rustc_promotable]` attribute
+    pub promotable: bool,
+    /// This is true iff the `const_stable_indirect` attribute is present.
+    pub const_stable_indirect: bool,
+}
+
+impl ConstStability {
+    pub fn from_partial(
+        PartialConstStability { level, feature, promotable }: PartialConstStability,
+        const_stable_indirect: bool,
+    ) -> Self {
+        Self { const_stable_indirect, level, feature, promotable }
+    }
+
+    /// The stability assigned to unmarked items when -Zforce-unstable-if-unmarked is set.
+    pub fn unmarked(const_stable_indirect: bool, regular_stab: Stability) -> Self {
+        Self {
+            feature: regular_stab.feature,
+            promotable: false,
+            level: regular_stab.level,
+            const_stable_indirect,
+        }
+    }
+
+    pub fn is_const_unstable(&self) -> bool {
+        self.level.is_unstable()
+    }
+
+    pub fn is_const_stable(&self) -> bool {
+        self.level.is_stable()
+    }
+}
+
+/// Excludes `const_stable_indirect`. This is necessary because when `-Zforce-unstable-if-unmarked`
+/// is set, we need to encode standalone `#[rustc_const_stable_indirect]` attributes
+#[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(HashStable_Generic)]
+pub struct PartialConstStability {
+    pub level: StabilityLevel,
+    pub feature: Symbol,
+    /// whether the function has a `#[rustc_promotable]` attribute
+    pub promotable: bool,
+}
+
+impl PartialConstStability {
+    pub fn is_const_unstable(&self) -> bool {
+        self.level.is_unstable()
+    }
+
+    pub fn is_const_stable(&self) -> bool {
+        self.level.is_stable()
+    }
+}
+
+/// The available stability levels.
+#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)]
+#[derive(HashStable_Generic)]
+pub enum StabilityLevel {
+    /// `#[unstable]`
+    Unstable {
+        /// Reason for the current stability level.
+        reason: UnstableReason,
+        /// Relevant `rust-lang/rust` issue.
+        issue: Option<NonZero<u32>>,
+        is_soft: bool,
+        /// If part of a feature is stabilized and a new feature is added for the remaining parts,
+        /// then the `implied_by` attribute is used to indicate which now-stable feature previously
+        /// contained an item.
+        ///
+        /// ```pseudo-Rust
+        /// #[unstable(feature = "foo", issue = "...")]
+        /// fn foo() {}
+        /// #[unstable(feature = "foo", issue = "...")]
+        /// fn foobar() {}
+        /// ```
+        ///
+        /// ...becomes...
+        ///
+        /// ```pseudo-Rust
+        /// #[stable(feature = "foo", since = "1.XX.X")]
+        /// fn foo() {}
+        /// #[unstable(feature = "foobar", issue = "...", implied_by = "foo")]
+        /// fn foobar() {}
+        /// ```
+        implied_by: Option<Symbol>,
+    },
+    /// `#[stable]`
+    Stable {
+        /// Rust release which stabilized this feature.
+        since: StableSince,
+        /// Is this item allowed to be referred to on stable, despite being contained in unstable
+        /// modules?
+        allowed_through_unstable_modules: bool,
+    },
+}
+
+/// Rust release in which a feature is stabilized.
+#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, PartialOrd, Ord, Hash)]
+#[derive(HashStable_Generic)]
+pub enum StableSince {
+    /// also stores the original symbol for printing
+    Version(RustcVersion),
+    /// Stabilized in the upcoming version, whatever number that is.
+    Current,
+    /// Failed to parse a stabilization version.
+    Err,
+}
+
+impl StabilityLevel {
+    pub fn is_unstable(&self) -> bool {
+        matches!(self, StabilityLevel::Unstable { .. })
+    }
+    pub fn is_stable(&self) -> bool {
+        matches!(self, StabilityLevel::Stable { .. })
+    }
+    pub fn stable_since(&self) -> Option<StableSince> {
+        match *self {
+            StabilityLevel::Stable { since, .. } => Some(since),
+            StabilityLevel::Unstable { .. } => None,
+        }
+    }
+}
+
+#[derive(Encodable, Decodable, PartialEq, Copy, Clone, Debug, Eq, Hash)]
+#[derive(HashStable_Generic)]
+pub enum UnstableReason {
+    None,
+    Default,
+    Some(Symbol),
+}
+
+/// Represents the `#[rustc_default_body_unstable]` attribute.
+#[derive(Encodable, Decodable, Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(HashStable_Generic)]
+pub struct DefaultBodyStability {
+    pub level: StabilityLevel,
+    pub feature: Symbol,
+}
+
+impl UnstableReason {
+    pub fn from_opt_reason(reason: Option<Symbol>) -> Self {
+        // UnstableReason::Default constructed manually
+        match reason {
+            Some(r) => Self::Some(r),
+            None => Self::None,
+        }
+    }
+
+    pub fn to_opt_reason(&self) -> Option<Symbol> {
+        match self {
+            Self::None => None,
+            Self::Default => Some(sym::unstable_location_reason_default),
+            Self::Some(r) => Some(*r),
+        }
+    }
+}