//! List of the active feature gates. use super::{Feature, State}; use rustc_span::edition::Edition; use rustc_span::symbol::{sym, Symbol}; use rustc_span::Span; macro_rules! set { ($field: ident) => {{ fn f(features: &mut Features, _: Span) { features.$field = true; } f as fn(&mut Features, Span) }}; } macro_rules! declare_features { ($( $(#[doc = $doc:tt])* (active, $feature:ident, $ver:expr, $issue:expr, $edition:expr), )+) => { /// Represents active features that are currently being implemented or /// currently being considered for addition/removal. pub const ACTIVE_FEATURES: &[Feature] = &[$( // (sym::$feature, $ver, $issue, $edition, set!($feature)) Feature { state: State::Active { set: set!($feature) }, name: sym::$feature, since: $ver, issue: $issue, edition: $edition, description: concat!($($doc,)*), } ),+]; /// A set of features to be used by later passes. #[derive(Clone, Default)] pub struct Features { /// `#![feature]` attrs for language features, for error reporting. pub declared_lang_features: Vec<(Symbol, Span, Option)>, /// `#![feature]` attrs for non-language (library) features. pub declared_lib_features: Vec<(Symbol, Span)>, $( $(#[doc = $doc])* pub $feature: bool ),+ } impl Features { pub fn walk_feature_fields(&self, mut f: impl FnMut(&str, bool)) { $(f(stringify!($feature), self.$feature);)+ } /// Is the given feature enabled? /// /// Panics if the symbol doesn't correspond to a declared feature. pub fn enabled(&self, feature: Symbol) -> bool { match feature { $( sym::$feature => self.$feature, )* _ => panic!("`{}` was not listed in `declare_features`", feature), } } } }; } impl Feature { /// Sets this feature in `Features`. Panics if called on a non-active feature. pub fn set(&self, features: &mut Features, span: Span) { match self.state { State::Active { set } => set(features, span), _ => panic!("called `set` on feature `{}` which is not `active`", self.name), } } } // If you change this, please modify `src/doc/unstable-book` as well. // // Don't ever remove anything from this list; move them to `removed.rs`. // // The version numbers here correspond to the version in which the current status // was set. This is most important for knowing when a particular feature became // stable (active). // // Note that the features are grouped into internal/user-facing and then // sorted by version inside those groups. This is enforced with tidy. // // N.B., `tools/tidy/src/features.rs` parses this information directly out of the // source, so take care when modifying it. #[rustfmt::skip] declare_features! ( // ------------------------------------------------------------------------- // feature-group-start: internal feature gates // ------------------------------------------------------------------------- // no-tracking-issue-start /// Allows using `rustc_*` attributes (RFC 572). (active, rustc_attrs, "1.0.0", None, None), /// Allows using compiler's own crates. (active, rustc_private, "1.0.0", Some(27812), None), /// Allows using the `rust-intrinsic`'s "ABI". (active, intrinsics, "1.0.0", None, None), /// Allows using `#[lang = ".."]` attribute for linking items to special compiler logic. (active, lang_items, "1.0.0", None, None), /// Allows using the `#[stable]` and `#[unstable]` attributes. (active, staged_api, "1.0.0", None, None), /// Allows using `#[allow_internal_unstable]`. This is an /// attribute on `macro_rules!` and can't use the attribute handling /// below (it has to be checked before expansion possibly makes /// macros disappear). (active, allow_internal_unstable, "1.0.0", None, None), /// Allows using `#[allow_internal_unsafe]`. This is an /// attribute on `macro_rules!` and can't use the attribute handling /// below (it has to be checked before expansion possibly makes /// macros disappear). (active, allow_internal_unsafe, "1.0.0", None, None), /// no-tracking-issue-end /// Allows using `#[link_name="llvm.*"]`. (active, link_llvm_intrinsics, "1.0.0", Some(29602), None), /// Allows using the `box $expr` syntax. (active, box_syntax, "1.0.0", Some(49733), None), /// Allows using `#[main]` to replace the entrypoint `#[lang = "start"]` calls. (active, main, "1.0.0", Some(29634), None), /// Allows using `#[start]` on a function indicating that it is the program entrypoint. (active, start, "1.0.0", Some(29633), None), /// Allows using the `#[fundamental]` attribute. (active, fundamental, "1.0.0", Some(29635), None), /// Allows using the `rust-call` ABI. (active, unboxed_closures, "1.0.0", Some(29625), None), /// Allows using the `#[linkage = ".."]` attribute. (active, linkage, "1.0.0", Some(29603), None), /// Allows features specific to OIBIT (auto traits). (active, optin_builtin_traits, "1.0.0", Some(13231), None), /// Allows using `box` in patterns (RFC 469). (active, box_patterns, "1.0.0", Some(29641), None), // no-tracking-issue-start /// Allows using `#[prelude_import]` on glob `use` items. (active, prelude_import, "1.2.0", None, None), // no-tracking-issue-end // no-tracking-issue-start /// Allows using `#[omit_gdb_pretty_printer_section]`. (active, omit_gdb_pretty_printer_section, "1.5.0", None, None), /// Allows using the `vectorcall` ABI. (active, abi_vectorcall, "1.7.0", None, None), // no-tracking-issue-end /// Allows using `#[structural_match]` which indicates that a type is structurally matchable. (active, structural_match, "1.8.0", Some(31434), None), /// Allows using the `may_dangle` attribute (RFC 1327). (active, dropck_eyepatch, "1.10.0", Some(34761), None), /// Allows using the `#![panic_runtime]` attribute. (active, panic_runtime, "1.10.0", Some(32837), None), /// Allows declaring with `#![needs_panic_runtime]` that a panic runtime is needed. (active, needs_panic_runtime, "1.10.0", Some(32837), None), // no-tracking-issue-start /// Allows identifying the `compiler_builtins` crate. (active, compiler_builtins, "1.13.0", None, None), /// Allows using the `unadjusted` ABI; perma-unstable. (active, abi_unadjusted, "1.16.0", None, None), /// Used to identify crates that contain the profiler runtime. (active, profiler_runtime, "1.18.0", None, None), /// Allows using the `thiscall` ABI. (active, abi_thiscall, "1.19.0", None, None), /// Allows using `#![needs_allocator]`, an implementation detail of `#[global_allocator]`. (active, allocator_internals, "1.20.0", None, None), /// Added for testing E0705; perma-unstable. (active, test_2018_feature, "1.31.0", None, Some(Edition::Edition2018)), /// Allows `#[repr(no_niche)]` (an implementation detail of `rustc`, /// it is not on path for eventual stabilization). (active, no_niche, "1.42.0", None, None), // no-tracking-issue-end // ------------------------------------------------------------------------- // feature-group-end: internal feature gates // ------------------------------------------------------------------------- // ------------------------------------------------------------------------- // feature-group-start: actual feature gates (target features) // ------------------------------------------------------------------------- // FIXME: Document these and merge with the list below. // Unstable `#[target_feature]` directives. (active, arm_target_feature, "1.27.0", Some(44839), None), (active, aarch64_target_feature, "1.27.0", Some(44839), None), (active, hexagon_target_feature, "1.27.0", Some(44839), None), (active, powerpc_target_feature, "1.27.0", Some(44839), None), (active, mips_target_feature, "1.27.0", Some(44839), None), (active, avx512_target_feature, "1.27.0", Some(44839), None), (active, mmx_target_feature, "1.27.0", Some(44839), None), (active, sse4a_target_feature, "1.27.0", Some(44839), None), (active, tbm_target_feature, "1.27.0", Some(44839), None), (active, wasm_target_feature, "1.30.0", Some(44839), None), (active, adx_target_feature, "1.32.0", Some(44839), None), (active, cmpxchg16b_target_feature, "1.32.0", Some(44839), None), (active, movbe_target_feature, "1.34.0", Some(44839), None), (active, rtm_target_feature, "1.35.0", Some(44839), None), (active, f16c_target_feature, "1.36.0", Some(44839), None), // ------------------------------------------------------------------------- // feature-group-end: actual feature gates (target features) // ------------------------------------------------------------------------- // ------------------------------------------------------------------------- // feature-group-start: actual feature gates // ------------------------------------------------------------------------- /// Allows using the `#[link_args]` attribute. (active, link_args, "1.0.0", Some(29596), None), /// Allows defining identifiers beyond ASCII. (active, non_ascii_idents, "1.0.0", Some(55467), None), /// Allows using `#[plugin_registrar]` on functions. (active, plugin_registrar, "1.0.0", Some(29597), None), /// Allows using `#![plugin(myplugin)]`. (active, plugin, "1.0.0", Some(29597), None), /// Allows using `#[thread_local]` on `static` items. (active, thread_local, "1.0.0", Some(29594), None), /// Allows the use of SIMD types in functions declared in `extern` blocks. (active, simd_ffi, "1.0.0", Some(27731), None), /// Allows using non lexical lifetimes (RFC 2094). (active, nll, "1.0.0", Some(43234), None), /// Allows the definition of `const` functions with some advanced features. (active, const_fn, "1.2.0", Some(57563), None), /// Allows associated type defaults. (active, associated_type_defaults, "1.2.0", Some(29661), None), /// Allows `#![no_core]`. (active, no_core, "1.3.0", Some(29639), None), /// Allows default type parameters to influence type inference. (active, default_type_parameter_fallback, "1.3.0", Some(27336), None), /// Allows `repr(simd)` and importing the various simd intrinsics. (active, repr_simd, "1.4.0", Some(27731), None), /// Allows `extern "platform-intrinsic" { ... }`. (active, platform_intrinsics, "1.4.0", Some(27731), None), /// Allows `#[unwind(..)]`. /// /// Permits specifying whether a function should permit unwinding or abort on unwind. (active, unwind_attributes, "1.4.0", Some(58760), None), /// Allows attributes on expressions and non-item statements. (active, stmt_expr_attributes, "1.6.0", Some(15701), None), /// Allows the use of type ascription in expressions. (active, type_ascription, "1.6.0", Some(23416), None), /// Allows `cfg(target_thread_local)`. (active, cfg_target_thread_local, "1.7.0", Some(29594), None), /// Allows specialization of implementations (RFC 1210). (active, specialization, "1.7.0", Some(31844), None), /// Allows using `#[naked]` on functions. (active, naked_functions, "1.9.0", Some(32408), None), /// Allows `cfg(target_has_atomic = "...")`. (active, cfg_target_has_atomic, "1.9.0", Some(32976), None), /// Allows `X..Y` patterns. (active, exclusive_range_pattern, "1.11.0", Some(37854), None), /// Allows the `!` type. Does not imply 'exhaustive_patterns' (below) any more. (active, never_type, "1.13.0", Some(35121), None), /// Allows exhaustive pattern matching on types that contain uninhabited types. (active, exhaustive_patterns, "1.13.0", Some(51085), None), /// Allows `union`s to implement `Drop`. Moreover, `union`s may now include fields /// that don't implement `Copy` as long as they don't have any drop glue. /// This is checked recursively. On encountering type variable where no progress can be made, /// `T: Copy` is used as a substitute for "no drop glue". /// /// NOTE: A limited form of `union U { ... }` was accepted in 1.19.0. (active, untagged_unions, "1.13.0", Some(55149), None), /// Allows `#[link(..., cfg(..))]`. (active, link_cfg, "1.14.0", Some(37406), None), /// Allows `extern "ptx-*" fn()`. (active, abi_ptx, "1.15.0", Some(38788), None), /// Allows the `#[repr(i128)]` attribute for enums. (active, repr128, "1.16.0", Some(56071), None), /// Allows `#[link(kind="static-nobundle"...)]`. (active, static_nobundle, "1.16.0", Some(37403), None), /// Allows `extern "msp430-interrupt" fn()`. (active, abi_msp430_interrupt, "1.16.0", Some(38487), None), /// Allows declarative macros 2.0 (`macro`). (active, decl_macro, "1.17.0", Some(39412), None), /// Allows `extern "x86-interrupt" fn()`. (active, abi_x86_interrupt, "1.17.0", Some(40180), None), /// Allows a test to fail without failing the whole suite. (active, allow_fail, "1.19.0", Some(46488), None), /// Allows unsized tuple coercion. (active, unsized_tuple_coercion, "1.20.0", Some(42877), None), /// Allows defining generators. (active, generators, "1.21.0", Some(43122), None), /// Allows `#[doc(cfg(...))]`. (active, doc_cfg, "1.21.0", Some(43781), None), /// Allows `#[doc(masked)]`. (active, doc_masked, "1.21.0", Some(44027), None), /// Allows `#[doc(include = "some-file")]`. (active, external_doc, "1.22.0", Some(44732), None), /// Allows using `crate` as visibility modifier, synonymous with `pub(crate)`. (active, crate_visibility_modifier, "1.23.0", Some(53120), None), /// Allows defining `extern type`s. (active, extern_types, "1.23.0", Some(43467), None), /// Allows trait methods with arbitrary self types. (active, arbitrary_self_types, "1.23.0", Some(44874), None), /// Allows in-band quantification of lifetime bindings (e.g., `fn foo(x: &'a u8) -> &'a u8`). (active, in_band_lifetimes, "1.23.0", Some(44524), None), /// Allows associated types to be generic, e.g., `type Foo;` (RFC 1598). (active, generic_associated_types, "1.23.0", Some(44265), None), /// Allows defining `trait X = A + B;` alias items. (active, trait_alias, "1.24.0", Some(41517), None), /// 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 comparing raw pointers during const eval. (active, const_compare_raw_pointers, "1.27.0", Some(53020), None), /// Allows `#[doc(alias = "...")]`. (active, doc_alias, "1.27.0", Some(50146), 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 invocations on modules expressions and statements and /// procedural macros to expand to non-items. (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(...);`). (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 `[x; N]` where `x` is a constant (RFC 2203). (active, const_in_array_repeat_expressions, "1.37.0", Some(49147), 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 use of or-patterns (e.g., `0 | 1`). (active, or_patterns, "1.38.0", Some(54883), 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 `#[track_caller]` to be used which provides /// accurate caller location reporting during panic (RFC 2091). (active, track_caller, "1.40.0", Some(47809), 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 `if` and `match` in constants. (active, const_if_match, "1.41.0", Some(49146), 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 the use of `loop` and `while` in constants. (active, const_loop, "1.41.0", Some(52000), 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 patterns with concurrent by-move and by-ref bindings. /// For example, you can write `Foo(a, ref b)` where `a` is by-move and `b` is by-ref. (active, move_ref_pattern, "1.42.0", Some(68354), 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), // ------------------------------------------------------------------------- // 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::impl_trait_in_bindings, sym::generic_associated_types, sym::const_generics, sym::let_chains, sym::raw_dylib, sym::const_trait_impl, sym::const_trait_bound_opt_out, ];