e48b6b4599
# Stabilization report ## Summary This stabilizes using macro expansion in key-value attributes, like so: ```rust #[doc = include_str!("my_doc.md")] struct S; #[path = concat!(env!("OUT_DIR"), "/generated.rs")] mod m; ``` See the changes to the reference for details on what macros are allowed; see Petrochenkov's excellent blog post [on internals](https://internals.rust-lang.org/t/macro-expansion-points-in-attributes/11455) for alternatives that were considered and rejected ("why accept no more and no less?") This has been available on nightly since 1.50 with no major issues. ## Notes ### Accepted syntax The parser accepts arbitrary Rust expressions in this position, but any expression other than a macro invocation will ultimately lead to an error because it is not expected by the built-in expression forms (e.g., `#[doc]`). Note that decorators and the like may be able to observe other expression forms. ### Expansion ordering Expansion of macro expressions in "inert" attributes occurs after decorators have executed, analogously to macro expressions appearing in the function body or other parts of decorator input. There is currently no way for decorators to accept macros in key-value position if macro expansion must be performed before the decorator executes (if the macro can simply be copied into the output for later expansion, that can work). ## Test cases - https://github.com/rust-lang/rust/blob/master/src/test/ui/attributes/key-value-expansion-on-mac.rs - https://github.com/rust-lang/rust/blob/master/src/test/rustdoc/external-doc.rs The feature has also been dogfooded extensively in the compiler and standard library: - https://github.com/rust-lang/rust/pull/83329 - https://github.com/rust-lang/rust/pull/83230 - https://github.com/rust-lang/rust/pull/82641 - https://github.com/rust-lang/rust/pull/80534 ## Implementation history - Initial proposal: https://github.com/rust-lang/rust/issues/55414#issuecomment-554005412 - Experiment to see how much code it would break: https://github.com/rust-lang/rust/pull/67121 - Preliminary work to restrict expansion that would conflict with this feature: https://github.com/rust-lang/rust/pull/77271 - Initial implementation: https://github.com/rust-lang/rust/pull/78837 - Fix for an ICE: https://github.com/rust-lang/rust/pull/80563 ## Unresolved Questions ~~https://github.com/rust-lang/rust/pull/83366#issuecomment-805180738 listed some concerns, but they have been resolved as of this final report.~~ ## Additional Information There are two workarounds that have a similar effect for `#[doc]` attributes on nightly. One is to emulate this behavior by using a limited version of this feature that was stabilized for historical reasons: ```rust macro_rules! forward_inner_docs { ($e:expr => $i:item) => { #[doc = $e] $i }; } forward_inner_docs!(include_str!("lib.rs") => struct S {}); ``` This also works for other attributes (like `#[path = concat!(...)]`). The other is to use `doc(include)`: ```rust #![feature(external_doc)] #[doc(include = "lib.rs")] struct S {} ``` The first works, but is non-trivial for people to discover, and difficult to read and maintain. The second is a strange special-case for a particular use of the macro. This generalizes it to work for any use case, not just including files. I plan to remove `doc(include)` when this is stabilized. The `forward_inner_docs` workaround will still compile without warnings, but I expect it to be used less once it's no longer necessary.
716 lines
28 KiB
Rust
716 lines
28 KiB
Rust
//! List of the active feature gates.
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use super::{to_nonzero, Feature, State};
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use rustc_span::edition::Edition;
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use rustc_span::symbol::{sym, Symbol};
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use rustc_span::Span;
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macro_rules! set {
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($field: ident) => {{
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fn f(features: &mut Features, _: Span) {
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features.$field = true;
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}
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f as fn(&mut Features, Span)
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}};
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}
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macro_rules! declare_features {
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($(
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$(#[doc = $doc:tt])* (active, $feature:ident, $ver:expr, $issue:expr, $edition:expr),
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)+) => {
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/// Represents active features that are currently being implemented or
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/// currently being considered for addition/removal.
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pub const ACTIVE_FEATURES:
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&[Feature] =
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&[$(
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// (sym::$feature, $ver, $issue, $edition, set!($feature))
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Feature {
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state: State::Active { set: set!($feature) },
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name: sym::$feature,
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since: $ver,
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issue: to_nonzero($issue),
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edition: $edition,
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description: concat!($($doc,)*),
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}
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),+];
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/// A set of features to be used by later passes.
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#[derive(Clone, Default, Debug)]
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pub struct Features {
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/// `#![feature]` attrs for language features, for error reporting.
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pub declared_lang_features: Vec<(Symbol, Span, Option<Symbol>)>,
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/// `#![feature]` attrs for non-language (library) features.
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pub declared_lib_features: Vec<(Symbol, Span)>,
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$(
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$(#[doc = $doc])*
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pub $feature: bool
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),+
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}
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impl Features {
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pub fn walk_feature_fields(&self, mut f: impl FnMut(&str, bool)) {
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$(f(stringify!($feature), self.$feature);)+
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}
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/// Is the given feature enabled?
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///
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/// Panics if the symbol doesn't correspond to a declared feature.
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pub fn enabled(&self, feature: Symbol) -> bool {
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match feature {
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$( sym::$feature => self.$feature, )*
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_ => panic!("`{}` was not listed in `declare_features`", feature),
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}
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}
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pub fn unordered_const_ty_params(&self) -> bool {
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self.const_generics || self.const_generics_defaults
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}
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}
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};
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}
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impl Feature {
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/// Sets this feature in `Features`. Panics if called on a non-active feature.
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pub fn set(&self, features: &mut Features, span: Span) {
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match self.state {
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State::Active { set } => set(features, span),
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_ => panic!("called `set` on feature `{}` which is not `active`", self.name),
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}
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}
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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 `removed.rs`.
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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. This is most important for knowing when a particular feature became
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// stable (active).
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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 by version 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
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// -------------------------------------------------------------------------
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// no-tracking-issue-start
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/// Allows using `rustc_*` attributes (RFC 572).
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(active, rustc_attrs, "1.0.0", None, None),
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/// Allows using compiler's own crates.
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(active, rustc_private, "1.0.0", Some(27812), None),
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/// Allows using the `rust-intrinsic`'s "ABI".
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(active, intrinsics, "1.0.0", None, None),
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/// Allows using `#[lang = ".."]` attribute for linking items to special compiler logic.
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(active, lang_items, "1.0.0", None, None),
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/// Allows using the `#[stable]` and `#[unstable]` attributes.
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(active, staged_api, "1.0.0", None, 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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(active, allow_internal_unstable, "1.0.0", None, 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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(active, allow_internal_unsafe, "1.0.0", None, None),
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/// no-tracking-issue-end
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/// Allows using `#[link_name="llvm.*"]`.
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(active, link_llvm_intrinsics, "1.0.0", Some(29602), None),
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/// Allows using the `box $expr` syntax.
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(active, box_syntax, "1.0.0", Some(49733), None),
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/// Allows using `#[start]` on a function indicating that it is the program entrypoint.
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(active, start, "1.0.0", Some(29633), None),
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/// Allows using the `#[fundamental]` attribute.
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(active, fundamental, "1.0.0", Some(29635), None),
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/// Allows using the `rust-call` ABI.
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(active, unboxed_closures, "1.0.0", Some(29625), None),
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/// Allows using the `#[linkage = ".."]` attribute.
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(active, linkage, "1.0.0", Some(29603), None),
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/// Allows using `box` in patterns (RFC 469).
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(active, box_patterns, "1.0.0", Some(29641), None),
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// no-tracking-issue-start
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/// Allows using `#[prelude_import]` on glob `use` items.
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(active, prelude_import, "1.2.0", None, None),
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// no-tracking-issue-end
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// no-tracking-issue-start
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/// Allows using `#[omit_gdb_pretty_printer_section]`.
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(active, omit_gdb_pretty_printer_section, "1.5.0", None, None),
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/// Allows using the `vectorcall` ABI.
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(active, abi_vectorcall, "1.7.0", None, None),
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// no-tracking-issue-end
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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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(active, structural_match, "1.8.0", Some(31434), None),
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/// Allows using the `may_dangle` attribute (RFC 1327).
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(active, dropck_eyepatch, "1.10.0", Some(34761), None),
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/// Allows using the `#![panic_runtime]` attribute.
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(active, panic_runtime, "1.10.0", Some(32837), None),
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/// Allows declaring with `#![needs_panic_runtime]` that a panic runtime is needed.
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(active, needs_panic_runtime, "1.10.0", Some(32837), None),
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// no-tracking-issue-start
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/// Allows identifying the `compiler_builtins` crate.
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(active, compiler_builtins, "1.13.0", None, None),
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/// Allows using the `unadjusted` ABI; perma-unstable.
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(active, abi_unadjusted, "1.16.0", None, None),
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/// Used to identify crates that contain the profiler runtime.
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(active, profiler_runtime, "1.18.0", None, None),
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/// Allows using the `thiscall` ABI.
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(active, abi_thiscall, "1.19.0", None, None),
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/// Allows using `#![needs_allocator]`, an implementation detail of `#[global_allocator]`.
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(active, allocator_internals, "1.20.0", None, None),
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/// Added for testing E0705; perma-unstable.
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(active, test_2018_feature, "1.31.0", None, Some(Edition::Edition2018)),
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/// Allows `#[repr(no_niche)]` (an implementation detail of `rustc`,
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/// it is not on path for eventual stabilization).
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(active, no_niche, "1.42.0", None, None),
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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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(active, rustc_allow_const_fn_unstable, "1.49.0", Some(69399), None),
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/// Allows features specific to auto traits.
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/// Renamed from `optin_builtin_traits`.
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(active, auto_traits, "1.50.0", Some(13231), None),
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/// Allows `#[doc(notable_trait)]`.
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/// Renamed from `doc_spotlight`.
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(active, doc_notable_trait, "1.52.0", Some(45040), None),
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// no-tracking-issue-end
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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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(active, arm_target_feature, "1.27.0", Some(44839), None),
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(active, aarch64_target_feature, "1.27.0", Some(44839), None),
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(active, hexagon_target_feature, "1.27.0", Some(44839), None),
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(active, powerpc_target_feature, "1.27.0", Some(44839), None),
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(active, mips_target_feature, "1.27.0", Some(44839), None),
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(active, avx512_target_feature, "1.27.0", Some(44839), None),
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(active, sse4a_target_feature, "1.27.0", Some(44839), None),
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(active, tbm_target_feature, "1.27.0", Some(44839), None),
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(active, wasm_target_feature, "1.30.0", Some(44839), None),
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(active, adx_target_feature, "1.32.0", Some(44839), None),
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(active, cmpxchg16b_target_feature, "1.32.0", Some(44839), None),
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(active, movbe_target_feature, "1.34.0", Some(44839), None),
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(active, rtm_target_feature, "1.35.0", Some(44839), None),
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(active, f16c_target_feature, "1.36.0", Some(44839), None),
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(active, riscv_target_feature, "1.45.0", Some(44839), None),
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(active, ermsb_target_feature, "1.49.0", Some(44839), None),
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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 using `#[plugin_registrar]` on functions.
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(active, plugin_registrar, "1.0.0", Some(29597), None),
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/// Allows using `#![plugin(myplugin)]`.
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(active, plugin, "1.0.0", Some(29597), None),
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/// Allows using `#[thread_local]` on `static` items.
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(active, thread_local, "1.0.0", Some(29594), None),
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/// Allows the use of SIMD types in functions declared in `extern` blocks.
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(active, simd_ffi, "1.0.0", Some(27731), None),
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/// Allows using non lexical lifetimes (RFC 2094).
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(active, nll, "1.0.0", Some(43234), None),
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/// Allows associated type defaults.
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(active, associated_type_defaults, "1.2.0", Some(29661), None),
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/// Allows `#![no_core]`.
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(active, no_core, "1.3.0", Some(29639), None),
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/// Allows default type parameters to influence type inference.
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(active, default_type_parameter_fallback, "1.3.0", Some(27336), None),
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/// Allows `repr(simd)` and importing the various simd intrinsics.
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(active, repr_simd, "1.4.0", Some(27731), None),
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/// Allows `extern "platform-intrinsic" { ... }`.
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(active, platform_intrinsics, "1.4.0", Some(27731), None),
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/// Allows `#[unwind(..)]`.
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///
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/// Permits specifying whether a function should permit unwinding or abort on unwind.
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(active, unwind_attributes, "1.4.0", Some(58760), None),
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/// Allows attributes on expressions and non-item statements.
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(active, stmt_expr_attributes, "1.6.0", Some(15701), None),
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/// Allows the use of type ascription in expressions.
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(active, type_ascription, "1.6.0", Some(23416), None),
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/// Allows `cfg(target_thread_local)`.
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(active, cfg_target_thread_local, "1.7.0", Some(29594), None),
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/// Allows specialization of implementations (RFC 1210).
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(active, specialization, "1.7.0", Some(31844), None),
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/// A minimal, sound subset of specialization intended to be used by the
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/// standard library until the soundness issues with specialization
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/// are fixed.
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(active, min_specialization, "1.7.0", Some(31844), None),
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/// Allows using `#[naked]` on functions.
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(active, naked_functions, "1.9.0", Some(32408), None),
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/// Allows `cfg(target_has_atomic = "...")`.
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(active, cfg_target_has_atomic, "1.9.0", Some(32976), None),
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/// Allows `X..Y` patterns.
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(active, exclusive_range_pattern, "1.11.0", Some(37854), None),
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/// Allows the `!` type. Does not imply 'exhaustive_patterns' (below) any more.
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(active, never_type, "1.13.0", Some(35121), None),
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/// Allows exhaustive pattern matching on types that contain uninhabited types.
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(active, exhaustive_patterns, "1.13.0", Some(51085), None),
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/// Allows `union`s to implement `Drop`. Moreover, `union`s may now include fields
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/// that don't implement `Copy` as long as they don't have any drop glue.
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/// This is checked recursively. On encountering type variable where no progress can be made,
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/// `T: Copy` is used as a substitute for "no drop glue".
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///
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/// NOTE: A limited form of `union U { ... }` was accepted in 1.19.0.
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(active, untagged_unions, "1.13.0", Some(55149), None),
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/// Allows `#[link(..., cfg(..))]`.
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(active, link_cfg, "1.14.0", Some(37406), None),
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/// Allows `extern "ptx-*" fn()`.
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(active, abi_ptx, "1.15.0", Some(38788), None),
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/// Allows the `#[repr(i128)]` attribute for enums.
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(active, repr128, "1.16.0", Some(56071), None),
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/// Allows `#[link(kind="static-nobundle"...)]`.
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(active, static_nobundle, "1.16.0", Some(37403), None),
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/// Allows `extern "msp430-interrupt" fn()`.
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(active, abi_msp430_interrupt, "1.16.0", Some(38487), None),
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/// Allows declarative macros 2.0 (`macro`).
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(active, decl_macro, "1.17.0", Some(39412), None),
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/// Allows `extern "x86-interrupt" fn()`.
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(active, abi_x86_interrupt, "1.17.0", Some(40180), None),
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/// Allows a test to fail without failing the whole suite.
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(active, allow_fail, "1.19.0", Some(46488), None),
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/// Allows unsized tuple coercion.
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(active, unsized_tuple_coercion, "1.20.0", Some(42877), None),
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/// Allows defining generators.
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(active, generators, "1.21.0", Some(43122), None),
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/// Allows `#[doc(cfg(...))]`.
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(active, doc_cfg, "1.21.0", Some(43781), None),
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/// Allows `#[doc(masked)]`.
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(active, doc_masked, "1.21.0", Some(44027), None),
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/// Allows `#[doc(include = "some-file")]`.
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(active, external_doc, "1.22.0", Some(44732), None),
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/// Allows using `crate` as visibility modifier, synonymous with `pub(crate)`.
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(active, crate_visibility_modifier, "1.23.0", Some(53120), None),
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/// Allows defining `extern type`s.
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(active, extern_types, "1.23.0", Some(43467), None),
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/// Allows trait methods with arbitrary self types.
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(active, arbitrary_self_types, "1.23.0", Some(44874), None),
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/// Allows in-band quantification of lifetime bindings (e.g., `fn foo(x: &'a u8) -> &'a u8`).
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(active, in_band_lifetimes, "1.23.0", Some(44524), None),
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/// Allows associated types to be generic, e.g., `type Foo<T>;` (RFC 1598).
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(active, generic_associated_types, "1.23.0", Some(44265), None),
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/// Allows defining `trait X = A + B;` alias items.
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(active, trait_alias, "1.24.0", Some(41517), None),
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|
|
|
/// Allows inferring `'static` outlives requirements (RFC 2093).
|
|
(active, infer_static_outlives_requirements, "1.26.0", Some(54185), None),
|
|
|
|
/// Allows accessing fields of unions inside `const` functions.
|
|
(active, const_fn_union, "1.27.0", Some(51909), None),
|
|
|
|
/// Allows casting raw pointers to `usize` during const eval.
|
|
(active, const_raw_ptr_to_usize_cast, "1.27.0", Some(51910), None),
|
|
|
|
/// Allows dereferencing raw pointers during const eval.
|
|
(active, const_raw_ptr_deref, "1.27.0", Some(51911), None),
|
|
|
|
/// Allows inconsistent bounds in where clauses.
|
|
(active, trivial_bounds, "1.28.0", Some(48214), None),
|
|
|
|
/// Allows `'a: { break 'a; }`.
|
|
(active, label_break_value, "1.28.0", Some(48594), None),
|
|
|
|
/// Allows using `#[doc(keyword = "...")]`.
|
|
(active, doc_keyword, "1.28.0", Some(51315), None),
|
|
|
|
/// Allows using `try {...}` expressions.
|
|
(active, try_blocks, "1.29.0", Some(31436), None),
|
|
|
|
/// Allows defining an `#[alloc_error_handler]`.
|
|
(active, alloc_error_handler, "1.29.0", Some(51540), None),
|
|
|
|
/// Allows using the `amdgpu-kernel` ABI.
|
|
(active, abi_amdgpu_kernel, "1.29.0", Some(51575), None),
|
|
|
|
/// Allows panicking during const eval (producing compile-time errors).
|
|
(active, const_panic, "1.30.0", Some(51999), None),
|
|
|
|
/// Allows `#[marker]` on certain traits allowing overlapping implementations.
|
|
(active, marker_trait_attr, "1.30.0", Some(29864), None),
|
|
|
|
/// Allows macro attributes on expressions, statements and non-inline modules.
|
|
(active, proc_macro_hygiene, "1.30.0", Some(54727), None),
|
|
|
|
/// Allows unsized rvalues at arguments and parameters.
|
|
(active, unsized_locals, "1.30.0", Some(48055), None),
|
|
|
|
/// Allows custom test frameworks with `#![test_runner]` and `#[test_case]`.
|
|
(active, custom_test_frameworks, "1.30.0", Some(50297), None),
|
|
|
|
/// Allows non-builtin attributes in inner attribute position.
|
|
(active, custom_inner_attributes, "1.30.0", Some(54726), None),
|
|
|
|
/// Allows `impl Trait` in bindings (`let`, `const`, `static`).
|
|
(active, impl_trait_in_bindings, "1.30.0", Some(63065), None),
|
|
|
|
/// Allows using `reason` in lint attributes and the `#[expect(lint)]` lint check.
|
|
(active, lint_reasons, "1.31.0", Some(54503), None),
|
|
|
|
/// Allows exhaustive integer pattern matching on `usize` and `isize`.
|
|
(active, precise_pointer_size_matching, "1.32.0", Some(56354), None),
|
|
|
|
/// Allows using `#[ffi_returns_twice]` on foreign functions.
|
|
(active, ffi_returns_twice, "1.34.0", Some(58314), None),
|
|
|
|
/// Allows const generic types (e.g. `struct Foo<const N: usize>(...);`).
|
|
(active, const_generics, "1.34.0", Some(44580), None),
|
|
|
|
/// Allows using `#[optimize(X)]`.
|
|
(active, optimize_attribute, "1.34.0", Some(54882), None),
|
|
|
|
/// Allows using C-variadics.
|
|
(active, c_variadic, "1.34.0", Some(44930), None),
|
|
|
|
/// Allows the user of associated type bounds.
|
|
(active, associated_type_bounds, "1.34.0", Some(52662), None),
|
|
|
|
/// Allows `if/while p && let q = r && ...` chains.
|
|
(active, let_chains, "1.37.0", Some(53667), None),
|
|
|
|
/// Allows #[repr(transparent)] on unions (RFC 2645).
|
|
(active, transparent_unions, "1.37.0", Some(60405), None),
|
|
|
|
/// Allows explicit discriminants on non-unit enum variants.
|
|
(active, arbitrary_enum_discriminant, "1.37.0", Some(60553), None),
|
|
|
|
/// Allows `impl Trait` with multiple unrelated lifetimes.
|
|
(active, member_constraints, "1.37.0", Some(61997), None),
|
|
|
|
/// Allows `async || body` closures.
|
|
(active, async_closure, "1.37.0", Some(62290), None),
|
|
|
|
/// Allows `impl Trait` to be used inside type aliases (RFC 2515).
|
|
(active, type_alias_impl_trait, "1.38.0", Some(63063), None),
|
|
|
|
/// Allows the definition of `const extern fn` and `const unsafe extern fn`.
|
|
(active, const_extern_fn, "1.40.0", Some(64926), None),
|
|
|
|
/// Allows the use of raw-dylibs (RFC 2627).
|
|
(active, raw_dylib, "1.40.0", Some(58713), None),
|
|
|
|
/// Allows making `dyn Trait` well-formed even if `Trait` is not object safe.
|
|
/// In that case, `dyn Trait: Trait` does not hold. Moreover, coercions and
|
|
/// casts in safe Rust to `dyn Trait` for such a `Trait` is also forbidden.
|
|
(active, object_safe_for_dispatch, "1.40.0", Some(43561), None),
|
|
|
|
/// Allows using the `efiapi` ABI.
|
|
(active, abi_efiapi, "1.40.0", Some(65815), None),
|
|
|
|
/// Allows `&raw const $place_expr` and `&raw mut $place_expr` expressions.
|
|
(active, raw_ref_op, "1.41.0", Some(64490), None),
|
|
|
|
/// Allows diverging expressions to fall back to `!` rather than `()`.
|
|
(active, never_type_fallback, "1.41.0", Some(65992), None),
|
|
|
|
/// Allows using the `#[register_attr]` attribute.
|
|
(active, register_attr, "1.41.0", Some(66080), None),
|
|
|
|
/// Allows using the `#[register_tool]` attribute.
|
|
(active, register_tool, "1.41.0", Some(66079), None),
|
|
|
|
/// Allows the use of `#[cfg(sanitize = "option")]`; set when -Zsanitizer is used.
|
|
(active, cfg_sanitize, "1.41.0", Some(39699), None),
|
|
|
|
/// Allows using `..X`, `..=X`, `...X`, and `X..` as a pattern.
|
|
(active, half_open_range_patterns, "1.41.0", Some(67264), None),
|
|
|
|
/// Allows using `&mut` in constant functions.
|
|
(active, const_mut_refs, "1.41.0", Some(57349), None),
|
|
|
|
/// Allows bindings in the subpattern of a binding pattern.
|
|
/// For example, you can write `x @ Some(y)`.
|
|
(active, bindings_after_at, "1.41.0", Some(65490), None),
|
|
|
|
/// Allows `impl const Trait for T` syntax.
|
|
(active, const_trait_impl, "1.42.0", Some(67792), None),
|
|
|
|
/// Allows `T: ?const Trait` syntax in bounds.
|
|
(active, const_trait_bound_opt_out, "1.42.0", Some(67794), None),
|
|
|
|
/// Allows the use of `no_sanitize` attribute.
|
|
(active, no_sanitize, "1.42.0", Some(39699), None),
|
|
|
|
// Allows limiting the evaluation steps of const expressions
|
|
(active, const_eval_limit, "1.43.0", Some(67217), None),
|
|
|
|
/// Allow negative trait implementations.
|
|
(active, negative_impls, "1.44.0", Some(68318), None),
|
|
|
|
/// Allows the use of `#[target_feature]` on safe functions.
|
|
(active, target_feature_11, "1.45.0", Some(69098), None),
|
|
|
|
/// Allow conditional compilation depending on rust version
|
|
(active, cfg_version, "1.45.0", Some(64796), None),
|
|
|
|
/// Allows the use of `#[ffi_pure]` on foreign functions.
|
|
(active, ffi_pure, "1.45.0", Some(58329), None),
|
|
|
|
/// Allows the use of `#[ffi_const]` on foreign functions.
|
|
(active, ffi_const, "1.45.0", Some(58328), None),
|
|
|
|
/// Allows `extern "avr-interrupt" fn()` and `extern "avr-non-blocking-interrupt" fn()`.
|
|
(active, abi_avr_interrupt, "1.45.0", Some(69664), None),
|
|
|
|
/// Be more precise when looking for live drops in a const context.
|
|
(active, const_precise_live_drops, "1.46.0", Some(73255), None),
|
|
|
|
/// Allows capturing variables in scope using format_args!
|
|
(active, format_args_capture, "1.46.0", Some(67984), None),
|
|
|
|
/// Lazily evaluate constants. This allows constants to depend on type parameters.
|
|
(active, lazy_normalization_consts, "1.46.0", Some(72219), None),
|
|
|
|
/// Allows calling `transmute` in const fn
|
|
(active, const_fn_transmute, "1.46.0", Some(53605), None),
|
|
|
|
/// Allows `if let` guard in match arms.
|
|
(active, if_let_guard, "1.47.0", Some(51114), None),
|
|
|
|
/// Allows non-trivial generic constants which have to be manually propagated upwards.
|
|
(active, const_evaluatable_checked, "1.48.0", Some(76560), None),
|
|
|
|
/// Allows basic arithmetic on floating point types in a `const fn`.
|
|
(active, const_fn_floating_point_arithmetic, "1.48.0", Some(57241), None),
|
|
|
|
/// Allows using and casting function pointers in a `const fn`.
|
|
(active, const_fn_fn_ptr_basics, "1.48.0", Some(57563), None),
|
|
|
|
/// Allows to use the `#[cmse_nonsecure_entry]` attribute.
|
|
(active, cmse_nonsecure_entry, "1.48.0", Some(75835), None),
|
|
|
|
/// Allows rustc to inject a default alloc_error_handler
|
|
(active, default_alloc_error_handler, "1.48.0", Some(66741), None),
|
|
|
|
/// Allows argument and return position `impl Trait` in a `const fn`.
|
|
(active, const_impl_trait, "1.48.0", Some(77463), None),
|
|
|
|
/// Allows `#[instruction_set(_)]` attribute
|
|
(active, isa_attribute, "1.48.0", Some(74727), None),
|
|
|
|
/// Allow anonymous constants from an inline `const` block
|
|
(active, inline_const, "1.49.0", Some(76001), None),
|
|
|
|
/// Allows unsized fn parameters.
|
|
(active, unsized_fn_params, "1.49.0", Some(48055), None),
|
|
|
|
/// Allows the use of destructuring assignments.
|
|
(active, destructuring_assignment, "1.49.0", Some(71126), None),
|
|
|
|
/// Enables `#[cfg(panic = "...")]` config key.
|
|
(active, cfg_panic, "1.49.0", Some(77443), None),
|
|
|
|
/// Allows capturing disjoint fields in a closure/generator (RFC 2229).
|
|
(active, capture_disjoint_fields, "1.49.0", Some(53488), None),
|
|
|
|
/// Allows const generics to have default values (e.g. `struct Foo<const N: usize = 3>(...);`).
|
|
(active, const_generics_defaults, "1.51.0", Some(44580), None),
|
|
|
|
/// Allows references to types with interior mutability within constants
|
|
(active, const_refs_to_cell, "1.51.0", Some(80384), None),
|
|
|
|
/// Allows using `pointer` and `reference` in intra-doc links
|
|
(active, intra_doc_pointers, "1.51.0", Some(80896), None),
|
|
|
|
/// Allows `extern "C-cmse-nonsecure-call" fn()`.
|
|
(active, abi_c_cmse_nonsecure_call, "1.51.0", Some(81391), None),
|
|
|
|
/// Lessens the requirements for structs to implement `Unsize`.
|
|
(active, relaxed_struct_unsize, "1.51.0", Some(81793), None),
|
|
|
|
/// Allows macro attributes to observe output of `#[derive]`.
|
|
(active, macro_attributes_in_derive_output, "1.51.0", Some(81119), None),
|
|
|
|
/// Allows the use of type alias impl trait in function return positions
|
|
(active, min_type_alias_impl_trait, "1.52.0", Some(63063), None),
|
|
|
|
/// Allows associated types in inherent impls.
|
|
(active, inherent_associated_types, "1.52.0", Some(8995), None),
|
|
|
|
// Allows setting the threshold for the `large_assignments` lint.
|
|
(active, large_assignments, "1.52.0", Some(83518), None),
|
|
|
|
/// Allows `extern "C-unwind" fn` to enable unwinding across ABI boundaries.
|
|
(active, c_unwind, "1.52.0", Some(74990), None),
|
|
|
|
/// Allows using `#[repr(align(...))]` on function items
|
|
(active, fn_align, "1.53.0", Some(82232), None),
|
|
|
|
/// Allows `extern "wasm" fn`
|
|
(active, wasm_abi, "1.53.0", Some(83788), None),
|
|
|
|
/// Allows function attribute `#[no_coverage]`, to bypass coverage
|
|
/// instrumentation of that function.
|
|
(active, no_coverage, "1.53.0", Some(84605), None),
|
|
|
|
/// Allows trait bounds in `const fn`.
|
|
(active, const_fn_trait_bound, "1.53.0", Some(57563), None),
|
|
|
|
/// Allows unsizing coercions in `const fn`.
|
|
(active, const_fn_unsize, "1.53.0", Some(64992), None),
|
|
|
|
/// Allows `async {}` expressions in const contexts.
|
|
(active, const_async_blocks, "1.53.0", Some(85368), None),
|
|
|
|
/// Allows using imported `main` function
|
|
(active, imported_main, "1.53.0", Some(28937), None),
|
|
|
|
/// Allows specifying modifiers in the link attribute: `#[link(modifiers = "...")]`
|
|
(active, native_link_modifiers, "1.53.0", Some(81490), None),
|
|
|
|
/// Allows specifying the bundle link modifier
|
|
(active, native_link_modifiers_bundle, "1.53.0", Some(81490), None),
|
|
|
|
/// Allows specifying the verbatim link modifier
|
|
(active, native_link_modifiers_verbatim, "1.53.0", Some(81490), None),
|
|
|
|
/// Allows specifying the whole-archive link modifier
|
|
(active, native_link_modifiers_whole_archive, "1.53.0", Some(81490), None),
|
|
|
|
/// Allows specifying the as-needed link modifier
|
|
(active, native_link_modifiers_as_needed, "1.53.0", Some(81490), None),
|
|
|
|
/// Allows unnamed fields of struct and union type
|
|
(active, unnamed_fields, "1.53.0", Some(49804), None),
|
|
|
|
// -------------------------------------------------------------------------
|
|
// feature-group-end: actual feature gates
|
|
// -------------------------------------------------------------------------
|
|
);
|
|
|
|
/// Some features are known to be incomplete and using them is likely to have
|
|
/// unanticipated results, such as compiler crashes. We warn the user about these
|
|
/// to alert them.
|
|
pub const INCOMPLETE_FEATURES: &[Symbol] = &[
|
|
sym::if_let_guard,
|
|
sym::impl_trait_in_bindings,
|
|
sym::generic_associated_types,
|
|
sym::const_generics,
|
|
sym::let_chains,
|
|
sym::raw_dylib,
|
|
sym::const_evaluatable_checked,
|
|
sym::const_trait_impl,
|
|
sym::const_trait_bound_opt_out,
|
|
sym::lazy_normalization_consts,
|
|
sym::specialization,
|
|
sym::inline_const,
|
|
sym::repr128,
|
|
sym::unsized_locals,
|
|
sym::capture_disjoint_fields,
|
|
sym::const_generics_defaults,
|
|
sym::inherent_associated_types,
|
|
sym::type_alias_impl_trait,
|
|
sym::native_link_modifiers,
|
|
sym::native_link_modifiers_bundle,
|
|
sym::native_link_modifiers_verbatim,
|
|
sym::native_link_modifiers_whole_archive,
|
|
sym::native_link_modifiers_as_needed,
|
|
sym::rustc_insignificant_dtor,
|
|
sym::unnamed_fields,
|
|
];
|
|
|
|
/// 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)] = &[];
|