mirror of
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dd31713c53
This commit seeks to stabilize the `#[diagnostic::do_not_recommend]`
attribute.
This attribute was first proposed as `#[do_not_recommend`] attribute in
RFC 2397 (https://github.com/rust-lang/rfcs/pull/2397). It gives the
crate authors the ability to not suggest to the compiler to not show
certain traits in it's error messages. With the presence of the
`#[diagnostic]` tool attribute namespace it was decided to move the
attribute there, as that lowers the amount of guarantees the compiler
needs to give about the exact way this influences error messages. It
turns the attribute into a hint which can be ignored. In addition to the
original proposed functionality this attribute now also hides the marked
trait in help messages ("This trait is implemented by: ").
The attribute does not accept any argument and can only be placed on
trait implementations. If it is placed somewhere else a lint warning is
emitted and the attribute is otherwise ignored. If an argument is
detected a lint warning is emitted and the argument is ignored. This
follows the rules outlined by the diagnostic namespace.
This attribute allows crates like diesel to improve their error messages
drastically. The most common example here is the following error
message:
```
error[E0277]: the trait bound `&str: Expression` is not satisfied
--> /home/weiznich/Documents/rust/rust/tests/ui/diagnostic_namespace/do_not_recommend.rs:53:15
|
LL | SelectInt.check("bar");
| ^^^^^ the trait `Expression` is not implemented for `&str`, which is required by `&str: AsExpression<Integer>`
|
= help: the following other types implement trait `Expression`:
Bound<T>
SelectInt
note: required for `&str` to implement `AsExpression<Integer>`
--> /home/weiznich/Documents/rust/rust/tests/ui/diagnostic_namespace/do_not_recommend.rs:26:13
|
LL | impl<T, ST> AsExpression<ST> for T
| ^^^^^^^^^^^^^^^^ ^
LL | where
LL | T: Expression<SqlType = ST>,
| ------------------------ unsatisfied trait bound introduced here
```
By applying the new attribute to the wild card trait implementation of
`AsExpression` for `T: Expression` the error message becomes:
```
error[E0277]: the trait bound `&str: AsExpression<Integer>` is not satisfied
--> $DIR/as_expression.rs:55:15
|
LL | SelectInt.check("bar");
| ^^^^^ the trait `AsExpression<Integer>` is not implemented for `&str`
|
= help: the trait `AsExpression<Text>` is implemented for `&str`
= help: for that trait implementation, expected `Text`, found `Integer`
```
which makes it much easier for users to understand that they are facing
a type mismatch.
Other explored example usages included
* This standard library error message: https://github.com/rust-lang/rust/pull/128008
* That bevy derived example:
e1f3068995/tests/ui/diagnostic_namespace/do_not_recommend/supress_suggestions_in_help.rs (No
more tuple pyramids)
Fixes #51992
720 lines
37 KiB
Rust
720 lines
37 KiB
Rust
//! List of the unstable feature gates.
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use std::path::PathBuf;
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use rustc_data_structures::fx::FxHashSet;
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use rustc_span::{Span, Symbol, sym};
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use super::{Feature, to_nonzero};
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#[derive(PartialEq)]
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enum FeatureStatus {
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Default,
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Incomplete,
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Internal,
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}
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macro_rules! status_to_enum {
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(unstable) => {
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FeatureStatus::Default
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};
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(incomplete) => {
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FeatureStatus::Incomplete
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};
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(internal) => {
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FeatureStatus::Internal
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};
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}
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/// A set of features to be used by later passes.
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///
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/// There are two ways to check if a language feature `foo` is enabled:
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/// - Directly with the `foo` method, e.g. `if tcx.features().foo() { ... }`.
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/// - With the `enabled` method, e.g. `if tcx.features.enabled(sym::foo) { ... }`.
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///
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/// The former is preferred. `enabled` should only be used when the feature symbol is not a
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/// constant, e.g. a parameter, or when the feature is a library feature.
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#[derive(Clone, Default, Debug)]
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pub struct Features {
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/// `#![feature]` attrs for language features, for error reporting.
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enabled_lang_features: Vec<EnabledLangFeature>,
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/// `#![feature]` attrs for non-language (library) features.
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enabled_lib_features: Vec<EnabledLibFeature>,
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/// `enabled_lang_features` + `enabled_lib_features`.
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enabled_features: FxHashSet<Symbol>,
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}
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/// Information about an enabled language feature.
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#[derive(Debug, Copy, Clone)]
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pub struct EnabledLangFeature {
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/// Name of the feature gate guarding the language feature.
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pub gate_name: Symbol,
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/// Span of the `#[feature(...)]` attribute.
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pub attr_sp: Span,
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/// If the lang feature is stable, the version number when it was stabilized.
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pub stable_since: Option<Symbol>,
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}
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/// Information about an enabled library feature.
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#[derive(Debug, Copy, Clone)]
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pub struct EnabledLibFeature {
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pub gate_name: Symbol,
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pub attr_sp: Span,
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}
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impl Features {
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/// `since` should be set for stable features that are nevertheless enabled with a `#[feature]`
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/// attribute, indicating since when they are stable.
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pub fn set_enabled_lang_feature(&mut self, lang_feat: EnabledLangFeature) {
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self.enabled_lang_features.push(lang_feat);
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self.enabled_features.insert(lang_feat.gate_name);
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}
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pub fn set_enabled_lib_feature(&mut self, lib_feat: EnabledLibFeature) {
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self.enabled_lib_features.push(lib_feat);
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self.enabled_features.insert(lib_feat.gate_name);
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}
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/// Returns a list of [`EnabledLangFeature`] with info about:
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///
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/// - Feature gate name.
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/// - The span of the `#[feature]` attribute.
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/// - For stable language features, version info for when it was stabilized.
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pub fn enabled_lang_features(&self) -> &Vec<EnabledLangFeature> {
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&self.enabled_lang_features
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}
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pub fn enabled_lib_features(&self) -> &Vec<EnabledLibFeature> {
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&self.enabled_lib_features
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}
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pub fn enabled_features(&self) -> &FxHashSet<Symbol> {
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&self.enabled_features
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}
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/// Is the given feature enabled (via `#[feature(...)]`)?
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pub fn enabled(&self, feature: Symbol) -> bool {
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self.enabled_features.contains(&feature)
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}
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}
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macro_rules! declare_features {
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($(
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$(#[doc = $doc:tt])* ($status:ident, $feature:ident, $ver:expr, $issue:expr),
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)+) => {
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/// Unstable language features that are being implemented or being
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/// considered for acceptance (stabilization) or removal.
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pub const UNSTABLE_LANG_FEATURES: &[Feature] = &[
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$(Feature {
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name: sym::$feature,
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since: $ver,
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issue: to_nonzero($issue),
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}),+
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];
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impl Features {
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$(
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pub fn $feature(&self) -> bool {
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self.enabled_features.contains(&sym::$feature)
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}
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)*
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/// Some features are known to be incomplete and using them is likely to have
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/// unanticipated results, such as compiler crashes. We warn the user about these
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/// to alert them.
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pub fn incomplete(&self, feature: Symbol) -> bool {
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match feature {
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$(
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sym::$feature => status_to_enum!($status) == FeatureStatus::Incomplete,
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)*
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_ if self.enabled_features.contains(&feature) => {
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// Accepted/removed features and library features aren't in this file but
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// are never incomplete.
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false
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}
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_ => panic!("`{}` was not listed in `declare_features`", feature),
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}
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}
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/// Some features are internal to the compiler and standard library and should not
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/// be used in normal projects. We warn the user about these to alert them.
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pub fn internal(&self, feature: Symbol) -> bool {
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match feature {
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$(
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sym::$feature => status_to_enum!($status) == FeatureStatus::Internal,
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)*
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_ if self.enabled_features.contains(&feature) => {
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// This could be accepted/removed, or a libs feature.
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// Accepted/removed features aren't in this file but are never internal
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// (a removed feature might have been internal, but that's now irrelevant).
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// Libs features are internal if they end in `_internal` or `_internals`.
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// As a special exception we also consider `core_intrinsics` internal;
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// renaming that age-old feature is just not worth the hassle.
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// We just always test the name; it's not a big deal if we accidentally hit
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// an accepted/removed lang feature that way.
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let name = feature.as_str();
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name == "core_intrinsics" || name.ends_with("_internal") || name.ends_with("_internals")
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}
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_ => panic!("`{}` was not listed in `declare_features`", feature),
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}
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}
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}
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};
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}
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// See https://rustc-dev-guide.rust-lang.org/feature-gates.html#feature-gates for more
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// documentation about handling feature gates.
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//
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// If you change this, please modify `src/doc/unstable-book` as well.
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//
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// Don't ever remove anything from this list; move them to `accepted.rs` if
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// accepted or `removed.rs` if removed.
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//
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// The version numbers here correspond to the version in which the current status
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// was set.
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//
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// Note that the features are grouped into internal/user-facing and then
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// sorted alphabetically inside those groups. This is enforced with tidy.
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//
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// N.B., `tools/tidy/src/features.rs` parses this information directly out of the
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// source, so take care when modifying it.
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#[rustfmt::skip]
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declare_features! (
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// -------------------------------------------------------------------------
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// feature-group-start: internal feature gates (no tracking issue)
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// -------------------------------------------------------------------------
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// no-tracking-issue-start
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/// Allows using the `unadjusted` ABI; perma-unstable.
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(internal, abi_unadjusted, "1.16.0", None),
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/// Allows using `#![needs_allocator]`, an implementation detail of `#[global_allocator]`.
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(internal, allocator_internals, "1.20.0", None),
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/// Allows using `#[allow_internal_unsafe]`. This is an
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/// attribute on `macro_rules!` and can't use the attribute handling
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/// below (it has to be checked before expansion possibly makes
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/// macros disappear).
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(internal, allow_internal_unsafe, "1.0.0", None),
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/// Allows using `#[allow_internal_unstable]`. This is an
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/// attribute on `macro_rules!` and can't use the attribute handling
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/// below (it has to be checked before expansion possibly makes
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/// macros disappear).
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(internal, allow_internal_unstable, "1.0.0", None),
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/// Allows using anonymous lifetimes in argument-position impl-trait.
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(unstable, anonymous_lifetime_in_impl_trait, "1.63.0", None),
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/// Allows identifying the `compiler_builtins` crate.
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(internal, compiler_builtins, "1.13.0", None),
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/// Allows writing custom MIR
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(internal, custom_mir, "1.65.0", None),
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/// Outputs useful `assert!` messages
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(unstable, generic_assert, "1.63.0", None),
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/// Allows using the `rust-intrinsic`'s "ABI".
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(internal, intrinsics, "1.0.0", None),
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/// Allows using `#[lang = ".."]` attribute for linking items to special compiler logic.
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(internal, lang_items, "1.0.0", None),
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/// Changes `impl Trait` to capture all lifetimes in scope.
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(unstable, lifetime_capture_rules_2024, "1.76.0", None),
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/// Allows `#[link(..., cfg(..))]`; perma-unstable per #37406
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(internal, link_cfg, "1.14.0", None),
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/// Allows using `?Trait` trait bounds in more contexts.
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(internal, more_maybe_bounds, "1.82.0", None),
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/// Allows the `multiple_supertrait_upcastable` lint.
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(unstable, multiple_supertrait_upcastable, "1.69.0", None),
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/// Allow negative trait bounds. This is an internal-only feature for testing the trait solver!
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(internal, negative_bounds, "1.71.0", None),
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/// Allows using `#[omit_gdb_pretty_printer_section]`.
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(internal, omit_gdb_pretty_printer_section, "1.5.0", None),
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/// Set the maximum pattern complexity allowed (not limited by default).
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(internal, pattern_complexity, "1.78.0", None),
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/// Allows using pattern types.
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(internal, pattern_types, "1.79.0", Some(123646)),
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/// Allows using `#[prelude_import]` on glob `use` items.
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(internal, prelude_import, "1.2.0", None),
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/// Used to identify crates that contain the profiler runtime.
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(internal, profiler_runtime, "1.18.0", None),
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/// Allows using `rustc_*` attributes (RFC 572).
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(internal, rustc_attrs, "1.0.0", None),
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/// Allows using the `#[stable]` and `#[unstable]` attributes.
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(internal, staged_api, "1.0.0", None),
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/// Added for testing unstable lints; perma-unstable.
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(internal, test_unstable_lint, "1.60.0", None),
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/// Helps with formatting for `group_imports = "StdExternalCrate"`.
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(unstable, unqualified_local_imports, "1.83.0", None),
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/// Use for stable + negative coherence and strict coherence depending on trait's
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/// rustc_strict_coherence value.
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(unstable, with_negative_coherence, "1.60.0", None),
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// !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
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// Features are listed in alphabetical order. Tidy will fail if you don't keep it this way.
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// !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
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// no-tracking-issue-end
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// -------------------------------------------------------------------------
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// feature-group-end: internal feature gates (no tracking issue)
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// -------------------------------------------------------------------------
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// -------------------------------------------------------------------------
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// feature-group-start: internal feature gates
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// -------------------------------------------------------------------------
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/// Allows using the `vectorcall` ABI.
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(unstable, abi_vectorcall, "1.7.0", Some(124485)),
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/// Allows features specific to auto traits.
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/// Renamed from `optin_builtin_traits`.
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(unstable, auto_traits, "1.50.0", Some(13231)),
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/// Allows using `box` in patterns (RFC 469).
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(unstable, box_patterns, "1.0.0", Some(29641)),
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/// Allows builtin # foo() syntax
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(internal, builtin_syntax, "1.71.0", Some(110680)),
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/// Allows `#[doc(notable_trait)]`.
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/// Renamed from `doc_spotlight`.
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(unstable, doc_notable_trait, "1.52.0", Some(45040)),
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/// Allows using the `may_dangle` attribute (RFC 1327).
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(unstable, dropck_eyepatch, "1.10.0", Some(34761)),
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/// Allows making `dyn Trait` well-formed even if `Trait` is not dyn-compatible[^1].
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/// In that case, `dyn Trait: Trait` does not hold. Moreover, coercions and
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/// casts in safe Rust to `dyn Trait` for such a `Trait` is also forbidden.
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///
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/// Renamed from `object_safe_for_dispatch`.
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///
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/// [^1]: Formerly known as "object safe".
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(unstable, dyn_compatible_for_dispatch, "1.83.0", Some(43561)),
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/// Allows using the `#[fundamental]` attribute.
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(unstable, fundamental, "1.0.0", Some(29635)),
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/// Allows using `#[link_name="llvm.*"]`.
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(internal, link_llvm_intrinsics, "1.0.0", Some(29602)),
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/// Allows using the `#[linkage = ".."]` attribute.
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(unstable, linkage, "1.0.0", Some(29603)),
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/// Allows declaring with `#![needs_panic_runtime]` that a panic runtime is needed.
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(internal, needs_panic_runtime, "1.10.0", Some(32837)),
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/// Allows using the `#![panic_runtime]` attribute.
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(internal, panic_runtime, "1.10.0", Some(32837)),
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/// Allows using `#[rustc_allow_const_fn_unstable]`.
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/// This is an attribute on `const fn` for the same
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/// purpose as `#[allow_internal_unstable]`.
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(internal, rustc_allow_const_fn_unstable, "1.49.0", Some(69399)),
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/// Allows using compiler's own crates.
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(unstable, rustc_private, "1.0.0", Some(27812)),
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/// Allows using internal rustdoc features like `doc(keyword)`.
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(internal, rustdoc_internals, "1.58.0", Some(90418)),
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/// Allows using the `rustdoc::missing_doc_code_examples` lint
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(unstable, rustdoc_missing_doc_code_examples, "1.31.0", Some(101730)),
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/// Allows using `#[start]` on a function indicating that it is the program entrypoint.
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(unstable, start, "1.0.0", Some(29633)),
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/// Allows using `#[structural_match]` which indicates that a type is structurally matchable.
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/// FIXME: Subsumed by trait `StructuralPartialEq`, cannot move to removed until a library
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/// feature with the same name exists.
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(unstable, structural_match, "1.8.0", Some(31434)),
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/// Allows using the `rust-call` ABI.
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(unstable, unboxed_closures, "1.0.0", Some(29625)),
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// !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
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// Features are listed in alphabetical order. Tidy will fail if you don't keep it this way.
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// !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
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// -------------------------------------------------------------------------
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// feature-group-end: internal feature gates
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// -------------------------------------------------------------------------
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// -------------------------------------------------------------------------
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// feature-group-start: actual feature gates (target features)
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// -------------------------------------------------------------------------
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// FIXME: Document these and merge with the list below.
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// Unstable `#[target_feature]` directives.
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(unstable, aarch64_unstable_target_feature, "1.82.0", Some(44839)),
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(unstable, aarch64_ver_target_feature, "1.27.0", Some(44839)),
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(unstable, arm_target_feature, "1.27.0", Some(44839)),
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(unstable, avx512_target_feature, "1.27.0", Some(44839)),
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(unstable, bpf_target_feature, "1.54.0", Some(44839)),
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(unstable, csky_target_feature, "1.73.0", Some(44839)),
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(unstable, ermsb_target_feature, "1.49.0", Some(44839)),
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(unstable, hexagon_target_feature, "1.27.0", Some(44839)),
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(unstable, lahfsahf_target_feature, "1.78.0", Some(44839)),
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(unstable, loongarch_target_feature, "1.73.0", Some(44839)),
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(unstable, m68k_target_feature, "CURRENT_RUSTC_VERSION", Some(134328)),
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(unstable, mips_target_feature, "1.27.0", Some(44839)),
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(unstable, powerpc_target_feature, "1.27.0", Some(44839)),
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(unstable, prfchw_target_feature, "1.78.0", Some(44839)),
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(unstable, riscv_target_feature, "1.45.0", Some(44839)),
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(unstable, rtm_target_feature, "1.35.0", Some(44839)),
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(unstable, s390x_target_feature, "1.82.0", Some(44839)),
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(unstable, sparc_target_feature, "1.84.0", Some(132783)),
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(unstable, sse4a_target_feature, "1.27.0", Some(44839)),
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(unstable, tbm_target_feature, "1.27.0", Some(44839)),
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(unstable, wasm_target_feature, "1.30.0", Some(44839)),
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(unstable, x87_target_feature, "CURRENT_RUSTC_VERSION", Some(44839)),
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// !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
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// Features are listed in alphabetical order. Tidy will fail if you don't keep it this way.
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// !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
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// -------------------------------------------------------------------------
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// feature-group-end: actual feature gates (target features)
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// -------------------------------------------------------------------------
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// -------------------------------------------------------------------------
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// feature-group-start: actual feature gates
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// -------------------------------------------------------------------------
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/// Allows `extern "avr-interrupt" fn()` and `extern "avr-non-blocking-interrupt" fn()`.
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(unstable, abi_avr_interrupt, "1.45.0", Some(69664)),
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/// Allows `extern "C-cmse-nonsecure-call" fn()`.
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(unstable, abi_c_cmse_nonsecure_call, "1.51.0", Some(81391)),
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/// Allows `extern "msp430-interrupt" fn()`.
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(unstable, abi_msp430_interrupt, "1.16.0", Some(38487)),
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/// Allows `extern "ptx-*" fn()`.
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(unstable, abi_ptx, "1.15.0", Some(38788)),
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/// Allows `extern "riscv-interrupt-m" fn()` and `extern "riscv-interrupt-s" fn()`.
|
|
(unstable, abi_riscv_interrupt, "1.73.0", Some(111889)),
|
|
/// Allows `extern "x86-interrupt" fn()`.
|
|
(unstable, abi_x86_interrupt, "1.17.0", Some(40180)),
|
|
/// Allows additional const parameter types, such as `[u8; 10]` or user defined types
|
|
(unstable, adt_const_params, "1.56.0", Some(95174)),
|
|
/// Allows defining an `#[alloc_error_handler]`.
|
|
(unstable, alloc_error_handler, "1.29.0", Some(51540)),
|
|
/// Allows inherent and trait methods with arbitrary self types.
|
|
(unstable, arbitrary_self_types, "1.23.0", Some(44874)),
|
|
/// Allows inherent and trait methods with arbitrary self types that are raw pointers.
|
|
(unstable, arbitrary_self_types_pointers, "1.83.0", Some(44874)),
|
|
/// Enables experimental inline assembly support for additional architectures.
|
|
(unstable, asm_experimental_arch, "1.58.0", Some(93335)),
|
|
/// Enables experimental register support in inline assembly.
|
|
(unstable, asm_experimental_reg, "CURRENT_RUSTC_VERSION", Some(133416)),
|
|
/// Allows using `label` operands in inline assembly.
|
|
(unstable, asm_goto, "1.78.0", Some(119364)),
|
|
/// Allows using `label` operands in inline assembly together with output operands.
|
|
(unstable, asm_goto_with_outputs, "CURRENT_RUSTC_VERSION", Some(119364)),
|
|
/// Allows the `may_unwind` option in inline assembly.
|
|
(unstable, asm_unwind, "1.58.0", Some(93334)),
|
|
/// Allows users to enforce equality of associated constants `TraitImpl<AssocConst=3>`.
|
|
(unstable, associated_const_equality, "1.58.0", Some(92827)),
|
|
/// Allows associated type defaults.
|
|
(unstable, associated_type_defaults, "1.2.0", Some(29661)),
|
|
/// Allows async functions to be called from `dyn Trait`.
|
|
(incomplete, async_fn_in_dyn_trait, "CURRENT_RUSTC_VERSION", Some(133119)),
|
|
/// Allows `#[track_caller]` on async functions.
|
|
(unstable, async_fn_track_caller, "1.73.0", Some(110011)),
|
|
/// Allows `for await` loops.
|
|
(unstable, async_for_loop, "1.77.0", Some(118898)),
|
|
/// Allows `async` trait bound modifier.
|
|
(unstable, async_trait_bounds, "CURRENT_RUSTC_VERSION", Some(62290)),
|
|
/// Allows using C-variadics.
|
|
(unstable, c_variadic, "1.34.0", Some(44930)),
|
|
/// Allows the use of `#[cfg(<true/false>)]`.
|
|
(unstable, cfg_boolean_literals, "1.83.0", Some(131204)),
|
|
/// Allows the use of `#[cfg(overflow_checks)` to check if integer overflow behaviour.
|
|
(unstable, cfg_overflow_checks, "1.71.0", Some(111466)),
|
|
/// Provides the relocation model information as cfg entry
|
|
(unstable, cfg_relocation_model, "1.73.0", Some(114929)),
|
|
/// Allows the use of `#[cfg(sanitize = "option")]`; set when -Zsanitizer is used.
|
|
(unstable, cfg_sanitize, "1.41.0", Some(39699)),
|
|
/// Allows `cfg(sanitizer_cfi_generalize_pointers)` and `cfg(sanitizer_cfi_normalize_integers)`.
|
|
(unstable, cfg_sanitizer_cfi, "1.77.0", Some(89653)),
|
|
/// Allows `cfg(target(abi = "..."))`.
|
|
(unstable, cfg_target_compact, "1.63.0", Some(96901)),
|
|
/// Allows `cfg(target_has_atomic_load_store = "...")`.
|
|
(unstable, cfg_target_has_atomic, "1.60.0", Some(94039)),
|
|
/// Allows `cfg(target_has_atomic_equal_alignment = "...")`.
|
|
(unstable, cfg_target_has_atomic_equal_alignment, "1.60.0", Some(93822)),
|
|
/// Allows `cfg(target_thread_local)`.
|
|
(unstable, cfg_target_thread_local, "1.7.0", Some(29594)),
|
|
/// Allows the use of `#[cfg(ub_checks)` to check if UB checks are enabled.
|
|
(unstable, cfg_ub_checks, "1.79.0", Some(123499)),
|
|
/// Allow conditional compilation depending on rust version
|
|
(unstable, cfg_version, "1.45.0", Some(64796)),
|
|
/// Allows to use the `#[cfi_encoding = ""]` attribute.
|
|
(unstable, cfi_encoding, "1.71.0", Some(89653)),
|
|
/// Allows `for<...>` on closures and coroutines.
|
|
(unstable, closure_lifetime_binder, "1.64.0", Some(97362)),
|
|
/// Allows `#[track_caller]` on closures and coroutines.
|
|
(unstable, closure_track_caller, "1.57.0", Some(87417)),
|
|
/// Allows `extern "C-cmse-nonsecure-entry" fn()`.
|
|
(unstable, cmse_nonsecure_entry, "1.48.0", Some(75835)),
|
|
/// Allows `async {}` expressions in const contexts.
|
|
(unstable, const_async_blocks, "1.53.0", Some(85368)),
|
|
/// Allows `const || {}` closures in const contexts.
|
|
(incomplete, const_closures, "1.68.0", Some(106003)),
|
|
/// Allows using `~const Destruct` bounds and calling drop impls in const contexts.
|
|
(unstable, const_destruct, "CURRENT_RUSTC_VERSION", Some(133214)),
|
|
/// Allows `for _ in _` loops in const contexts.
|
|
(unstable, const_for, "1.56.0", Some(87575)),
|
|
/// Be more precise when looking for live drops in a const context.
|
|
(unstable, const_precise_live_drops, "1.46.0", Some(73255)),
|
|
/// Allows `impl const Trait for T` syntax.
|
|
(unstable, const_trait_impl, "1.42.0", Some(67792)),
|
|
/// Allows the `?` operator in const contexts.
|
|
(unstable, const_try, "1.56.0", Some(74935)),
|
|
/// Allows coroutines to be cloned.
|
|
(unstable, coroutine_clone, "1.65.0", Some(95360)),
|
|
/// Allows defining coroutines.
|
|
(unstable, coroutines, "1.21.0", Some(43122)),
|
|
/// Allows non-builtin attributes in inner attribute position.
|
|
(unstable, custom_inner_attributes, "1.30.0", Some(54726)),
|
|
/// Allows custom test frameworks with `#![test_runner]` and `#[test_case]`.
|
|
(unstable, custom_test_frameworks, "1.30.0", Some(50297)),
|
|
/// Allows declarative macros 2.0 (`macro`).
|
|
(unstable, decl_macro, "1.17.0", Some(39412)),
|
|
/// Allows the use of default values on struct definitions and the construction of struct
|
|
/// literals with the functional update syntax without a base.
|
|
(unstable, default_field_values, "CURRENT_RUSTC_VERSION", Some(132162)),
|
|
/// Allows using `#[deprecated_safe]` to deprecate the safeness of a function or trait
|
|
(unstable, deprecated_safe, "1.61.0", Some(94978)),
|
|
/// Allows having using `suggestion` in the `#[deprecated]` attribute.
|
|
(unstable, deprecated_suggestion, "1.61.0", Some(94785)),
|
|
/// Allows deref patterns.
|
|
(incomplete, deref_patterns, "1.79.0", Some(87121)),
|
|
/// Tells rustdoc to automatically generate `#[doc(cfg(...))]`.
|
|
(unstable, doc_auto_cfg, "1.58.0", Some(43781)),
|
|
/// Allows `#[doc(cfg(...))]`.
|
|
(unstable, doc_cfg, "1.21.0", Some(43781)),
|
|
/// Allows `#[doc(cfg_hide(...))]`.
|
|
(unstable, doc_cfg_hide, "1.57.0", Some(43781)),
|
|
/// Allows `#[doc(masked)]`.
|
|
(unstable, doc_masked, "1.21.0", Some(44027)),
|
|
/// Allows `dyn* Trait` objects.
|
|
(incomplete, dyn_star, "1.65.0", Some(102425)),
|
|
/// Allows exhaustive pattern matching on types that contain uninhabited types.
|
|
(unstable, exhaustive_patterns, "1.13.0", Some(51085)),
|
|
/// Allows explicit tail calls via `become` expression.
|
|
(incomplete, explicit_tail_calls, "1.72.0", Some(112788)),
|
|
/// Allows defining `extern type`s.
|
|
(unstable, extern_types, "1.23.0", Some(43467)),
|
|
/// Allow using 128-bit (quad precision) floating point numbers.
|
|
(unstable, f128, "1.78.0", Some(116909)),
|
|
/// Allow using 16-bit (half precision) floating point numbers.
|
|
(unstable, f16, "1.78.0", Some(116909)),
|
|
/// Allows the use of `#[ffi_const]` on foreign functions.
|
|
(unstable, ffi_const, "1.45.0", Some(58328)),
|
|
/// Allows the use of `#[ffi_pure]` on foreign functions.
|
|
(unstable, ffi_pure, "1.45.0", Some(58329)),
|
|
/// Controlling the behavior of fmt::Debug
|
|
(unstable, fmt_debug, "1.82.0", Some(129709)),
|
|
/// Allows using `#[repr(align(...))]` on function items
|
|
(unstable, fn_align, "1.53.0", Some(82232)),
|
|
/// Support delegating implementation of functions to other already implemented functions.
|
|
(incomplete, fn_delegation, "1.76.0", Some(118212)),
|
|
/// Allows impls for the Freeze trait.
|
|
(internal, freeze_impls, "1.78.0", Some(121675)),
|
|
/// Allows defining gen blocks and `gen fn`.
|
|
(unstable, gen_blocks, "1.75.0", Some(117078)),
|
|
/// Infer generic args for both consts and types.
|
|
(unstable, generic_arg_infer, "1.55.0", Some(85077)),
|
|
/// Allows non-trivial generic constants which have to have wfness manually propagated to callers
|
|
(incomplete, generic_const_exprs, "1.56.0", Some(76560)),
|
|
/// Allows generic parameters and where-clauses on free & associated const items.
|
|
(incomplete, generic_const_items, "1.73.0", Some(113521)),
|
|
/// Allows registering static items globally, possibly across crates, to iterate over at runtime.
|
|
(unstable, global_registration, "1.80.0", Some(125119)),
|
|
/// Allows using guards in patterns.
|
|
(incomplete, guard_patterns, "CURRENT_RUSTC_VERSION", Some(129967)),
|
|
/// Allows using `..=X` as a patterns in slices.
|
|
(unstable, half_open_range_patterns_in_slices, "1.66.0", Some(67264)),
|
|
/// Allows `if let` guard in match arms.
|
|
(unstable, if_let_guard, "1.47.0", Some(51114)),
|
|
/// Allows `impl Trait` to be used inside associated types (RFC 2515).
|
|
(unstable, impl_trait_in_assoc_type, "1.70.0", Some(63063)),
|
|
/// Allows `impl Trait` in bindings (`let`).
|
|
(unstable, impl_trait_in_bindings, "1.64.0", Some(63065)),
|
|
/// Allows `impl Trait` as output type in `Fn` traits in return position of functions.
|
|
(unstable, impl_trait_in_fn_trait_return, "1.64.0", Some(99697)),
|
|
/// Allows associated types in inherent impls.
|
|
(incomplete, inherent_associated_types, "1.52.0", Some(8995)),
|
|
/// Allow anonymous constants from an inline `const` block in pattern position
|
|
(unstable, inline_const_pat, "1.58.0", Some(76001)),
|
|
/// Allows using `pointer` and `reference` in intra-doc links
|
|
(unstable, intra_doc_pointers, "1.51.0", Some(80896)),
|
|
// Allows setting the threshold for the `large_assignments` lint.
|
|
(unstable, large_assignments, "1.52.0", Some(83518)),
|
|
/// Allow to have type alias types for inter-crate use.
|
|
(incomplete, lazy_type_alias, "1.72.0", Some(112792)),
|
|
/// Allows `if/while p && let q = r && ...` chains.
|
|
(unstable, let_chains, "1.37.0", Some(53667)),
|
|
/// Allows using `#[link(kind = "link-arg", name = "...")]`
|
|
/// to pass custom arguments to the linker.
|
|
(unstable, link_arg_attribute, "1.76.0", Some(99427)),
|
|
/// Give access to additional metadata about declarative macro meta-variables.
|
|
(unstable, macro_metavar_expr, "1.61.0", Some(83527)),
|
|
/// Provides a way to concatenate identifiers using metavariable expressions.
|
|
(unstable, macro_metavar_expr_concat, "1.81.0", Some(124225)),
|
|
/// Allows `#[marker]` on certain traits allowing overlapping implementations.
|
|
(unstable, marker_trait_attr, "1.30.0", Some(29864)),
|
|
/// Enables the generic const args MVP (only bare paths, not arbitrary computation).
|
|
(incomplete, min_generic_const_args, "1.84.0", Some(132980)),
|
|
/// A minimal, sound subset of specialization intended to be used by the
|
|
/// standard library until the soundness issues with specialization
|
|
/// are fixed.
|
|
(unstable, min_specialization, "1.7.0", Some(31844)),
|
|
/// Allows qualified paths in struct expressions, struct patterns and tuple struct patterns.
|
|
(unstable, more_qualified_paths, "1.54.0", Some(86935)),
|
|
/// Allows the `#[must_not_suspend]` attribute.
|
|
(unstable, must_not_suspend, "1.57.0", Some(83310)),
|
|
/// Allows `mut ref` and `mut ref mut` identifier patterns.
|
|
(incomplete, mut_ref, "1.79.0", Some(123076)),
|
|
/// Allows using `#[naked]` on functions.
|
|
(unstable, naked_functions, "1.9.0", Some(90957)),
|
|
/// Allows specifying the as-needed link modifier
|
|
(unstable, native_link_modifiers_as_needed, "1.53.0", Some(81490)),
|
|
/// Allow negative trait implementations.
|
|
(unstable, negative_impls, "1.44.0", Some(68318)),
|
|
/// Allows the `!` pattern.
|
|
(incomplete, never_patterns, "1.76.0", Some(118155)),
|
|
/// Allows the `!` type. Does not imply 'exhaustive_patterns' (below) any more.
|
|
(unstable, never_type, "1.13.0", Some(35121)),
|
|
/// Allows diverging expressions to fall back to `!` rather than `()`.
|
|
(unstable, never_type_fallback, "1.41.0", Some(65992)),
|
|
/// Allows `#![no_core]`.
|
|
(unstable, no_core, "1.3.0", Some(29639)),
|
|
/// Allows the use of `no_sanitize` attribute.
|
|
(unstable, no_sanitize, "1.42.0", Some(39699)),
|
|
/// Allows using the `non_exhaustive_omitted_patterns` lint.
|
|
(unstable, non_exhaustive_omitted_patterns_lint, "1.57.0", Some(89554)),
|
|
/// Allows `for<T>` binders in where-clauses
|
|
(incomplete, non_lifetime_binders, "1.69.0", Some(108185)),
|
|
/// Allows using enums in offset_of!
|
|
(unstable, offset_of_enum, "1.75.0", Some(120141)),
|
|
/// Allows using fields with slice type in offset_of!
|
|
(unstable, offset_of_slice, "1.81.0", Some(126151)),
|
|
/// Allows using `#[optimize(X)]`.
|
|
(unstable, optimize_attribute, "1.34.0", Some(54882)),
|
|
/// Allows specifying nop padding on functions for dynamic patching.
|
|
(unstable, patchable_function_entry, "1.81.0", Some(123115)),
|
|
/// Experimental features that make `Pin` more ergonomic.
|
|
(incomplete, pin_ergonomics, "1.83.0", Some(130494)),
|
|
/// Allows postfix match `expr.match { ... }`
|
|
(unstable, postfix_match, "1.79.0", Some(121618)),
|
|
/// Allows `use<..>` precise capturign on impl Trait in traits.
|
|
(unstable, precise_capturing_in_traits, "1.83.0", Some(130044)),
|
|
/// Allows macro attributes on expressions, statements and non-inline modules.
|
|
(unstable, proc_macro_hygiene, "1.30.0", Some(54727)),
|
|
/// Makes `&` and `&mut` patterns eat only one layer of references in Rust 2024.
|
|
(incomplete, ref_pat_eat_one_layer_2024, "1.79.0", Some(123076)),
|
|
/// Makes `&` and `&mut` patterns eat only one layer of references in Rust 2024—structural variant
|
|
(incomplete, ref_pat_eat_one_layer_2024_structural, "1.81.0", Some(123076)),
|
|
/// Allows using the `#[register_tool]` attribute.
|
|
(unstable, register_tool, "1.41.0", Some(66079)),
|
|
/// Allows the `#[repr(i128)]` attribute for enums.
|
|
(incomplete, repr128, "1.16.0", Some(56071)),
|
|
/// Allows `repr(simd)` and importing the various simd intrinsics.
|
|
(unstable, repr_simd, "1.4.0", Some(27731)),
|
|
/// Allows bounding the return type of AFIT/RPITIT.
|
|
(unstable, return_type_notation, "1.70.0", Some(109417)),
|
|
/// Allows `extern "rust-cold"`.
|
|
(unstable, rust_cold_cc, "1.63.0", Some(97544)),
|
|
/// Allows use of x86 SHA512, SM3 and SM4 target-features and intrinsics
|
|
(unstable, sha512_sm_x86, "1.82.0", Some(126624)),
|
|
/// Allows the use of SIMD types in functions declared in `extern` blocks.
|
|
(unstable, simd_ffi, "1.0.0", Some(27731)),
|
|
/// Allows specialization of implementations (RFC 1210).
|
|
(incomplete, specialization, "1.7.0", Some(31844)),
|
|
/// Allows attributes on expressions and non-item statements.
|
|
(unstable, stmt_expr_attributes, "1.6.0", Some(15701)),
|
|
/// Allows lints part of the strict provenance effort.
|
|
(unstable, strict_provenance_lints, "1.61.0", Some(130351)),
|
|
/// Allows string patterns to dereference values to match them.
|
|
(unstable, string_deref_patterns, "1.67.0", Some(87121)),
|
|
/// Allows the use of `#[target_feature]` on safe functions.
|
|
(unstable, target_feature_11, "1.45.0", Some(69098)),
|
|
/// Allows using `#[thread_local]` on `static` items.
|
|
(unstable, thread_local, "1.0.0", Some(29594)),
|
|
/// Allows defining `trait X = A + B;` alias items.
|
|
(unstable, trait_alias, "1.24.0", Some(41517)),
|
|
/// Allows dyn upcasting trait objects via supertraits.
|
|
/// Dyn upcasting is casting, e.g., `dyn Foo -> dyn Bar` where `Foo: Bar`.
|
|
(unstable, trait_upcasting, "1.56.0", Some(65991)),
|
|
/// Allows for transmuting between arrays with sizes that contain generic consts.
|
|
(unstable, transmute_generic_consts, "1.70.0", Some(109929)),
|
|
/// Allows #[repr(transparent)] on unions (RFC 2645).
|
|
(unstable, transparent_unions, "1.37.0", Some(60405)),
|
|
/// Allows inconsistent bounds in where clauses.
|
|
(unstable, trivial_bounds, "1.28.0", Some(48214)),
|
|
/// Allows using `try {...}` expressions.
|
|
(unstable, try_blocks, "1.29.0", Some(31436)),
|
|
/// Allows `impl Trait` to be used inside type aliases (RFC 2515).
|
|
(unstable, type_alias_impl_trait, "1.38.0", Some(63063)),
|
|
/// Allows creation of instances of a struct by moving fields that have
|
|
/// not changed from prior instances of the same struct (RFC #2528)
|
|
(unstable, type_changing_struct_update, "1.58.0", Some(86555)),
|
|
/// Allows using `unsafe<'a> &'a T` unsafe binder types.
|
|
(incomplete, unsafe_binders, "CURRENT_RUSTC_VERSION", Some(130516)),
|
|
/// Allows declaring fields `unsafe`.
|
|
(incomplete, unsafe_fields, "CURRENT_RUSTC_VERSION", Some(132922)),
|
|
/// Allows const generic parameters to be defined with types that
|
|
/// are not `Sized`, e.g. `fn foo<const N: [u8]>() {`.
|
|
(incomplete, unsized_const_params, "1.82.0", Some(95174)),
|
|
/// Allows unsized fn parameters.
|
|
(internal, unsized_fn_params, "1.49.0", Some(48055)),
|
|
/// Allows unsized rvalues at arguments and parameters.
|
|
(incomplete, unsized_locals, "1.30.0", Some(48055)),
|
|
/// Allows unsized tuple coercion.
|
|
(unstable, unsized_tuple_coercion, "1.20.0", Some(42877)),
|
|
/// Allows using the `#[used(linker)]` (or `#[used(compiler)]`) attribute.
|
|
(unstable, used_with_arg, "1.60.0", Some(93798)),
|
|
/// Allows use of x86 `AMX` target-feature attributes and intrinsics
|
|
(unstable, x86_amx_intrinsics, "1.81.0", Some(126622)),
|
|
/// Allows use of the `xop` target-feature
|
|
(unstable, xop_target_feature, "1.81.0", Some(127208)),
|
|
/// Allows `do yeet` expressions
|
|
(unstable, yeet_expr, "1.62.0", Some(96373)),
|
|
// !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
|
|
// Features are listed in alphabetical order. Tidy will fail if you don't keep it this way.
|
|
// !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
|
|
|
|
// -------------------------------------------------------------------------
|
|
// feature-group-end: actual feature gates
|
|
// -------------------------------------------------------------------------
|
|
);
|
|
|
|
impl Features {
|
|
pub fn dump_feature_usage_metrics(
|
|
&self,
|
|
metrics_path: PathBuf,
|
|
) -> Result<(), Box<dyn std::error::Error>> {
|
|
#[derive(serde::Serialize)]
|
|
struct LibFeature {
|
|
symbol: String,
|
|
}
|
|
|
|
#[derive(serde::Serialize)]
|
|
struct LangFeature {
|
|
symbol: String,
|
|
since: Option<String>,
|
|
}
|
|
|
|
#[derive(serde::Serialize)]
|
|
struct FeatureUsage {
|
|
lib_features: Vec<LibFeature>,
|
|
lang_features: Vec<LangFeature>,
|
|
}
|
|
|
|
let metrics_file = std::fs::File::create(metrics_path)?;
|
|
let metrics_file = std::io::BufWriter::new(metrics_file);
|
|
|
|
let lib_features = self
|
|
.enabled_lib_features
|
|
.iter()
|
|
.map(|EnabledLibFeature { gate_name, .. }| LibFeature { symbol: gate_name.to_string() })
|
|
.collect();
|
|
|
|
let lang_features = self
|
|
.enabled_lang_features
|
|
.iter()
|
|
.map(|EnabledLangFeature { gate_name, stable_since, .. }| LangFeature {
|
|
symbol: gate_name.to_string(),
|
|
since: stable_since.map(|since| since.to_string()),
|
|
})
|
|
.collect();
|
|
|
|
let feature_usage = FeatureUsage { lib_features, lang_features };
|
|
|
|
serde_json::to_writer(metrics_file, &feature_usage)?;
|
|
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
/// Some features are not allowed to be used together at the same time, if
|
|
/// the two are present, produce an error.
|
|
///
|
|
/// Currently empty, but we will probably need this again in the future,
|
|
/// so let's keep it in for now.
|
|
pub const INCOMPATIBLE_FEATURES: &[(Symbol, Symbol)] = &[];
|