1 //! List of the active feature gates.
3 use super::{to_nonzero, Feature, State};
5 use rustc_span::edition::Edition;
6 use rustc_span::symbol::{sym, Symbol};
11 fn f(features: &mut Features, _: Span) {
12 features.$field = true;
14 f as fn(&mut Features, Span)
18 macro_rules! declare_features {
19 (__status_to_bool active) => {
22 (__status_to_bool incomplete) => {
26 $(#[doc = $doc:tt])* ($status:ident, $feature:ident, $ver:expr, $issue:expr, $edition:expr),
28 /// Represents active features that are currently being implemented or
29 /// currently being considered for addition/removal.
30 pub const ACTIVE_FEATURES:
33 // (sym::$feature, $ver, $issue, $edition, set!($feature))
35 state: State::Active { set: set!($feature) },
38 issue: to_nonzero($issue),
43 /// A set of features to be used by later passes.
44 #[derive(Clone, Default, Debug)]
46 /// `#![feature]` attrs for language features, for error reporting.
47 pub declared_lang_features: Vec<(Symbol, Span, Option<Symbol>)>,
48 /// `#![feature]` attrs for non-language (library) features.
49 pub declared_lib_features: Vec<(Symbol, Span)>,
57 pub fn walk_feature_fields(&self, mut f: impl FnMut(&str, bool)) {
58 $(f(stringify!($feature), self.$feature);)+
61 /// Is the given feature enabled?
63 /// Panics if the symbol doesn't correspond to a declared feature.
64 pub fn enabled(&self, feature: Symbol) -> bool {
66 $( sym::$feature => self.$feature, )*
68 _ => panic!("`{}` was not listed in `declare_features`", feature),
72 /// Some features are known to be incomplete and using them is likely to have
73 /// unanticipated results, such as compiler crashes. We warn the user about these
75 pub fn incomplete(&self, feature: Symbol) -> bool {
78 sym::$feature => declare_features!(__status_to_bool $status),
80 // accepted and removed features aren't in this file but are never incomplete
81 _ if self.declared_lang_features.iter().any(|f| f.0 == feature) => false,
82 _ if self.declared_lib_features.iter().any(|f| f.0 == feature) => false,
83 _ => panic!("`{}` was not listed in `declare_features`", feature),
91 /// Sets this feature in `Features`. Panics if called on a non-active feature.
92 pub fn set(&self, features: &mut Features, span: Span) {
94 State::Active { set } => set(features, span),
95 _ => panic!("called `set` on feature `{}` which is not `active`", self.name),
100 // See https://rustc-dev-guide.rust-lang.org/feature-gates.html#feature-gates for more
101 // documentation about handling feature gates.
103 // If you change this, please modify `src/doc/unstable-book` as well.
105 // Don't ever remove anything from this list; move them to `accepted.rs` if
106 // accepted or `removed.rs` if removed.
108 // The version numbers here correspond to the version in which the current status
109 // was set. This is most important for knowing when a particular feature became
112 // Note that the features are grouped into internal/user-facing and then
113 // sorted by version inside those groups. This is enforced with tidy.
115 // N.B., `tools/tidy/src/features.rs` parses this information directly out of the
116 // source, so take care when modifying it.
120 // -------------------------------------------------------------------------
121 // feature-group-start: internal feature gates (no tracking issue)
122 // -------------------------------------------------------------------------
123 // no-tracking-issue-start
125 /// Allows using the `thiscall` ABI.
126 (active, abi_thiscall, "1.19.0", None, None),
127 /// Allows using the `unadjusted` ABI; perma-unstable.
128 (active, abi_unadjusted, "1.16.0", None, None),
129 /// Allows using the `vectorcall` ABI.
130 (active, abi_vectorcall, "1.7.0", None, None),
131 /// Allows using `#![needs_allocator]`, an implementation detail of `#[global_allocator]`.
132 (active, allocator_internals, "1.20.0", None, None),
133 /// Allows using `#[allow_internal_unsafe]`. This is an
134 /// attribute on `macro_rules!` and can't use the attribute handling
135 /// below (it has to be checked before expansion possibly makes
136 /// macros disappear).
137 (active, allow_internal_unsafe, "1.0.0", None, None),
138 /// Allows using `#[allow_internal_unstable]`. This is an
139 /// attribute on `macro_rules!` and can't use the attribute handling
140 /// below (it has to be checked before expansion possibly makes
141 /// macros disappear).
142 (active, allow_internal_unstable, "1.0.0", None, None),
143 /// Allows identifying the `compiler_builtins` crate.
144 (active, compiler_builtins, "1.13.0", None, None),
145 /// Allows using the `rust-intrinsic`'s "ABI".
146 (active, intrinsics, "1.0.0", None, None),
147 /// Allows using `#[lang = ".."]` attribute for linking items to special compiler logic.
148 (active, lang_items, "1.0.0", None, None),
149 /// Allows `#[repr(no_niche)]` (an implementation detail of `rustc`,
150 /// it is not on path for eventual stabilization).
151 (active, no_niche, "1.42.0", None, None),
152 /// Allows using `#[omit_gdb_pretty_printer_section]`.
153 (active, omit_gdb_pretty_printer_section, "1.5.0", None, None),
154 /// Allows using `#[prelude_import]` on glob `use` items.
155 (active, prelude_import, "1.2.0", None, None),
156 /// Used to identify crates that contain the profiler runtime.
157 (active, profiler_runtime, "1.18.0", None, None),
158 /// Allows using `rustc_*` attributes (RFC 572).
159 (active, rustc_attrs, "1.0.0", None, None),
160 /// Allows using the `#[stable]` and `#[unstable]` attributes.
161 (active, staged_api, "1.0.0", None, None),
162 /// Added for testing E0705; perma-unstable.
163 (active, test_2018_feature, "1.31.0", None, Some(Edition::Edition2018)),
164 // !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
165 // Features are listed in alphabetical order. Tidy will fail if you don't keep it this way.
166 // !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
168 // no-tracking-issue-end
169 // -------------------------------------------------------------------------
170 // feature-group-end: internal feature gates (no tracking issue)
171 // -------------------------------------------------------------------------
173 // -------------------------------------------------------------------------
174 // feature-group-start: internal feature gates
175 // -------------------------------------------------------------------------
177 /// Allows features specific to auto traits.
178 /// Renamed from `optin_builtin_traits`.
179 (active, auto_traits, "1.50.0", Some(13231), None),
180 /// Allows using `box` in patterns (RFC 469).
181 (active, box_patterns, "1.0.0", Some(29641), None),
182 /// Allows using the `box $expr` syntax.
183 (active, box_syntax, "1.0.0", Some(49733), None),
184 /// Allows `#[doc(notable_trait)]`.
185 /// Renamed from `doc_spotlight`.
186 (active, doc_notable_trait, "1.52.0", Some(45040), None),
187 /// Allows using the `may_dangle` attribute (RFC 1327).
188 (active, dropck_eyepatch, "1.10.0", Some(34761), None),
189 /// Allows using the `#[fundamental]` attribute.
190 (active, fundamental, "1.0.0", Some(29635), None),
191 /// Allows using `#[link_name="llvm.*"]`.
192 (active, link_llvm_intrinsics, "1.0.0", Some(29602), None),
193 /// Allows using the `#[linkage = ".."]` attribute.
194 (active, linkage, "1.0.0", Some(29603), None),
195 /// Allows declaring with `#![needs_panic_runtime]` that a panic runtime is needed.
196 (active, needs_panic_runtime, "1.10.0", Some(32837), None),
197 /// Allows using the `#![panic_runtime]` attribute.
198 (active, panic_runtime, "1.10.0", Some(32837), None),
199 /// Allows using `#[rustc_allow_const_fn_unstable]`.
200 /// This is an attribute on `const fn` for the same
201 /// purpose as `#[allow_internal_unstable]`.
202 (active, rustc_allow_const_fn_unstable, "1.49.0", Some(69399), None),
203 /// Allows using compiler's own crates.
204 (active, rustc_private, "1.0.0", Some(27812), None),
205 /// Allows using internal rustdoc features like `doc(primitive)` or `doc(keyword)`.
206 (active, rustdoc_internals, "1.58.0", Some(90418), None),
207 /// Allows using `#[start]` on a function indicating that it is the program entrypoint.
208 (active, start, "1.0.0", Some(29633), None),
209 /// Allows using `#[structural_match]` which indicates that a type is structurally matchable.
210 /// FIXME: Subsumed by trait `StructuralPartialEq`, cannot move to removed until a library
211 /// feature with the same name exists.
212 (active, structural_match, "1.8.0", Some(31434), None),
213 /// Allows using the `rust-call` ABI.
214 (active, unboxed_closures, "1.0.0", Some(29625), None),
215 // !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
216 // Features are listed in alphabetical order. Tidy will fail if you don't keep it this way.
217 // !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
219 // -------------------------------------------------------------------------
220 // feature-group-end: internal feature gates
221 // -------------------------------------------------------------------------
223 // -------------------------------------------------------------------------
224 // feature-group-start: actual feature gates (target features)
225 // -------------------------------------------------------------------------
227 // FIXME: Document these and merge with the list below.
229 // Unstable `#[target_feature]` directives.
230 (active, aarch64_target_feature, "1.27.0", Some(44839), None),
231 (active, adx_target_feature, "1.32.0", Some(44839), None),
232 (active, arm_target_feature, "1.27.0", Some(44839), None),
233 (active, avx512_target_feature, "1.27.0", Some(44839), None),
234 (active, bpf_target_feature, "1.54.0", Some(44839), None),
235 (active, cmpxchg16b_target_feature, "1.32.0", Some(44839), None),
236 (active, ermsb_target_feature, "1.49.0", Some(44839), None),
237 (active, f16c_target_feature, "1.36.0", Some(44839), None),
238 (active, hexagon_target_feature, "1.27.0", Some(44839), None),
239 (active, mips_target_feature, "1.27.0", Some(44839), None),
240 (active, movbe_target_feature, "1.34.0", Some(44839), None),
241 (active, powerpc_target_feature, "1.27.0", Some(44839), None),
242 (active, riscv_target_feature, "1.45.0", Some(44839), None),
243 (active, rtm_target_feature, "1.35.0", Some(44839), None),
244 (active, sse4a_target_feature, "1.27.0", Some(44839), None),
245 (active, tbm_target_feature, "1.27.0", Some(44839), None),
246 (active, wasm_target_feature, "1.30.0", Some(44839), None),
247 // !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
248 // Features are listed in alphabetical order. Tidy will fail if you don't keep it this way.
249 // !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
251 // -------------------------------------------------------------------------
252 // feature-group-end: actual feature gates (target features)
253 // -------------------------------------------------------------------------
255 // -------------------------------------------------------------------------
256 // feature-group-start: actual feature gates
257 // -------------------------------------------------------------------------
259 /// Allows using the `amdgpu-kernel` ABI.
260 (active, abi_amdgpu_kernel, "1.29.0", Some(51575), None),
261 /// Allows `extern "avr-interrupt" fn()` and `extern "avr-non-blocking-interrupt" fn()`.
262 (active, abi_avr_interrupt, "1.45.0", Some(69664), None),
263 /// Allows `extern "C-cmse-nonsecure-call" fn()`.
264 (active, abi_c_cmse_nonsecure_call, "1.51.0", Some(81391), None),
265 /// Allows using the `efiapi` ABI.
266 (active, abi_efiapi, "1.40.0", Some(65815), None),
267 /// Allows `extern "msp430-interrupt" fn()`.
268 (active, abi_msp430_interrupt, "1.16.0", Some(38487), None),
269 /// Allows `extern "ptx-*" fn()`.
270 (active, abi_ptx, "1.15.0", Some(38788), None),
271 /// Allows `extern "x86-interrupt" fn()`.
272 (active, abi_x86_interrupt, "1.17.0", Some(40180), None),
273 /// Allows additional const parameter types, such as `&'static str` or user defined types
274 (incomplete, adt_const_params, "1.56.0", Some(44580), None),
275 /// Allows defining an `#[alloc_error_handler]`.
276 (active, alloc_error_handler, "1.29.0", Some(51540), None),
277 /// Allows a test to fail without failing the whole suite.
278 (active, allow_fail, "1.19.0", Some(46488), None),
279 /// Allows explicit discriminants on non-unit enum variants.
280 (active, arbitrary_enum_discriminant, "1.37.0", Some(60553), None),
281 /// Allows trait methods with arbitrary self types.
282 (active, arbitrary_self_types, "1.23.0", Some(44874), None),
283 /// Allows using `const` operands in inline assembly.
284 (active, asm_const, "1.58.0", Some(72016), None),
285 /// Enables experimental inline assembly support for additional architectures.
286 (active, asm_experimental_arch, "1.58.0", Some(72016), None),
287 /// Allows using `sym` operands in inline assembly.
288 (active, asm_sym, "1.58.0", Some(72016), None),
289 /// Allows the `may_unwind` option in inline assembly.
290 (active, asm_unwind, "1.58.0", Some(72016), None),
291 /// Allows the user of associated type bounds.
292 (active, associated_type_bounds, "1.34.0", Some(52662), None),
293 /// Allows associated type defaults.
294 (active, associated_type_defaults, "1.2.0", Some(29661), None),
295 /// Allows `async || body` closures.
296 (active, async_closure, "1.37.0", Some(62290), None),
297 /// Allows `extern "C-unwind" fn` to enable unwinding across ABI boundaries.
298 (active, c_unwind, "1.52.0", Some(74990), None),
299 /// Allows using C-variadics.
300 (active, c_variadic, "1.34.0", Some(44930), None),
301 /// Allows capturing disjoint fields in a closure/generator (RFC 2229).
302 (incomplete, capture_disjoint_fields, "1.49.0", Some(53488), None),
303 /// Enables `#[cfg(panic = "...")]` config key.
304 (active, cfg_panic, "1.49.0", Some(77443), None),
305 /// Allows the use of `#[cfg(sanitize = "option")]`; set when -Zsanitizer is used.
306 (active, cfg_sanitize, "1.41.0", Some(39699), None),
307 /// Allows `cfg(target_abi = "...")`.
308 (active, cfg_target_abi, "1.55.0", Some(80970), None),
309 /// Allows `cfg(target_has_atomic = "...")`.
310 (active, cfg_target_has_atomic, "1.9.0", Some(32976), None),
311 /// Allows `cfg(target_thread_local)`.
312 (active, cfg_target_thread_local, "1.7.0", Some(29594), None),
313 /// Allow conditional compilation depending on rust version
314 (active, cfg_version, "1.45.0", Some(64796), None),
315 /// Allows `#[track_caller]` on closures and generators.
316 (active, closure_track_caller, "1.57.0", Some(87417), None),
317 /// Allows to use the `#[cmse_nonsecure_entry]` attribute.
318 (active, cmse_nonsecure_entry, "1.48.0", Some(75835), None),
319 /// Allows `async {}` expressions in const contexts.
320 (active, const_async_blocks, "1.53.0", Some(85368), None),
321 // Allows limiting the evaluation steps of const expressions
322 (active, const_eval_limit, "1.43.0", Some(67217), None),
323 /// Allows the definition of `const extern fn` and `const unsafe extern fn`.
324 (active, const_extern_fn, "1.40.0", Some(64926), None),
325 /// Allows basic arithmetic on floating point types in a `const fn`.
326 (active, const_fn_floating_point_arithmetic, "1.48.0", Some(57241), None),
327 /// Allows using and casting function pointers in a `const fn`.
328 (active, const_fn_fn_ptr_basics, "1.48.0", Some(57563), None),
329 /// Allows trait bounds in `const fn`.
330 (active, const_fn_trait_bound, "1.53.0", Some(57563), None),
331 /// Allows `for _ in _` loops in const contexts.
332 (active, const_for, "1.56.0", Some(87575), None),
333 /// Allows argument and return position `impl Trait` in a `const fn`.
334 (active, const_impl_trait, "1.48.0", Some(77463), None),
335 /// Allows using `&mut` in constant functions.
336 (active, const_mut_refs, "1.41.0", Some(57349), None),
337 /// Be more precise when looking for live drops in a const context.
338 (active, const_precise_live_drops, "1.46.0", Some(73255), None),
339 /// Allows references to types with interior mutability within constants
340 (active, const_refs_to_cell, "1.51.0", Some(80384), None),
341 /// Allows `impl const Trait for T` syntax.
342 (active, const_trait_impl, "1.42.0", Some(67792), None),
343 /// Allows the `?` operator in const contexts.
344 (active, const_try, "1.56.0", Some(74935), None),
345 /// Allows using `crate` as visibility modifier, synonymous with `pub(crate)`.
346 (active, crate_visibility_modifier, "1.23.0", Some(53120), None),
347 /// Allows non-builtin attributes in inner attribute position.
348 (active, custom_inner_attributes, "1.30.0", Some(54726), None),
349 /// Allows custom test frameworks with `#![test_runner]` and `#[test_case]`.
350 (active, custom_test_frameworks, "1.30.0", Some(50297), None),
351 /// Allows declarative macros 2.0 (`macro`).
352 (active, decl_macro, "1.17.0", Some(39412), None),
353 /// Allows rustc to inject a default alloc_error_handler
354 (active, default_alloc_error_handler, "1.48.0", Some(66741), None),
355 /// Allows default type parameters to influence type inference.
356 (active, default_type_parameter_fallback, "1.3.0", Some(27336), None),
357 /// Allows `#[derive(Default)]` and `#[default]` on enums.
358 (active, derive_default_enum, "1.56.0", Some(86985), None),
359 /// Allows the use of destructuring assignments.
360 (active, destructuring_assignment, "1.49.0", Some(71126), None),
361 /// Tells rustdoc to automatically generate `#[doc(cfg(...))]`.
362 (active, doc_auto_cfg, "1.58.0", Some(43781), None),
363 /// Allows `#[doc(cfg(...))]`.
364 (active, doc_cfg, "1.21.0", Some(43781), None),
365 /// Allows `#[doc(cfg_hide(...))]`.
366 (active, doc_cfg_hide, "1.57.0", Some(43781), None),
367 /// Allows `#[doc(masked)]`.
368 (active, doc_masked, "1.21.0", Some(44027), None),
369 /// Allows `X..Y` patterns.
370 (active, exclusive_range_pattern, "1.11.0", Some(37854), None),
371 /// Allows exhaustive pattern matching on types that contain uninhabited types.
372 (active, exhaustive_patterns, "1.13.0", Some(51085), None),
373 /// Allows explicit generic arguments specification with `impl Trait` present.
374 (active, explicit_generic_args_with_impl_trait, "1.56.0", Some(83701), None),
375 /// Allows defining `extern type`s.
376 (active, extern_types, "1.23.0", Some(43467), None),
377 /// Allows the use of `#[ffi_const]` on foreign functions.
378 (active, ffi_const, "1.45.0", Some(58328), None),
379 /// Allows the use of `#[ffi_pure]` on foreign functions.
380 (active, ffi_pure, "1.45.0", Some(58329), None),
381 /// Allows using `#[ffi_returns_twice]` on foreign functions.
382 (active, ffi_returns_twice, "1.34.0", Some(58314), None),
383 /// Allows using `#[repr(align(...))]` on function items
384 (active, fn_align, "1.53.0", Some(82232), None),
385 /// Allows defining generators.
386 (active, generators, "1.21.0", Some(43122), None),
387 /// Infer generic args for both consts and types.
388 (active, generic_arg_infer, "1.55.0", Some(85077), None),
389 /// Allows associated types to be generic, e.g., `type Foo<T>;` (RFC 1598).
390 (active, generic_associated_types, "1.23.0", Some(44265), None),
391 /// Allows non-trivial generic constants which have to have wfness manually propagated to callers
392 (incomplete, generic_const_exprs, "1.56.0", Some(76560), None),
393 /// Allows using `..X`, `..=X`, `...X`, and `X..` as a pattern.
394 (active, half_open_range_patterns, "1.41.0", Some(67264), None),
395 /// Allows `if let` guard in match arms.
396 (active, if_let_guard, "1.47.0", Some(51114), None),
397 /// Allows using imported `main` function
398 (active, imported_main, "1.53.0", Some(28937), None),
399 /// Allows in-band quantification of lifetime bindings (e.g., `fn foo(x: &'a u8) -> &'a u8`).
400 (active, in_band_lifetimes, "1.23.0", Some(44524), None),
401 /// Allows inferring `'static` outlives requirements (RFC 2093).
402 (active, infer_static_outlives_requirements, "1.26.0", Some(54185), None),
403 /// Allows associated types in inherent impls.
404 (incomplete, inherent_associated_types, "1.52.0", Some(8995), None),
405 /// Allow anonymous constants from an inline `const` block
406 (active, inline_const, "1.49.0", Some(76001), None),
407 /// Allow anonymous constants from an inline `const` block in pattern position
408 (incomplete, inline_const_pat, "1.58.0", Some(76001), None),
409 /// Allows using `pointer` and `reference` in intra-doc links
410 (active, intra_doc_pointers, "1.51.0", Some(80896), None),
411 /// Allows `#[instruction_set(_)]` attribute
412 (active, isa_attribute, "1.48.0", Some(74727), None),
413 /// Allows `'a: { break 'a; }`.
414 (active, label_break_value, "1.28.0", Some(48594), None),
415 // Allows setting the threshold for the `large_assignments` lint.
416 (active, large_assignments, "1.52.0", Some(83518), None),
417 /// Allows `if/while p && let q = r && ...` chains.
418 (incomplete, let_chains, "1.37.0", Some(53667), None),
419 /// Allows `let...else` statements.
420 (active, let_else, "1.56.0", Some(87335), None),
421 /// Allows `#[link(..., cfg(..))]`.
422 (active, link_cfg, "1.14.0", Some(37406), None),
423 /// Allows using `reason` in lint attributes and the `#[expect(lint)]` lint check.
424 (active, lint_reasons, "1.31.0", Some(54503), None),
425 /// Allows `#[marker]` on certain traits allowing overlapping implementations.
426 (active, marker_trait_attr, "1.30.0", Some(29864), None),
427 /// A minimal, sound subset of specialization intended to be used by the
428 /// standard library until the soundness issues with specialization
430 (active, min_specialization, "1.7.0", Some(31844), None),
431 /// Allows qualified paths in struct expressions, struct patterns and tuple struct patterns.
432 (active, more_qualified_paths, "1.54.0", Some(86935), None),
433 /// Allows the `#[must_not_suspend]` attribute.
434 (active, must_not_suspend, "1.57.0", Some(83310), None),
435 /// Allows using `#[naked]` on functions.
436 (active, naked_functions, "1.9.0", Some(32408), None),
437 /// Allows specifying modifiers in the link attribute: `#[link(modifiers = "...")]`
438 (active, native_link_modifiers, "1.53.0", Some(81490), None),
439 /// Allows specifying the as-needed link modifier
440 (active, native_link_modifiers_as_needed, "1.53.0", Some(81490), None),
441 /// Allows specifying the bundle link modifier
442 (active, native_link_modifiers_bundle, "1.53.0", Some(81490), None),
443 /// Allows specifying the verbatim link modifier
444 (active, native_link_modifiers_verbatim, "1.53.0", Some(81490), None),
445 /// Allows specifying the whole-archive link modifier
446 (active, native_link_modifiers_whole_archive, "1.53.0", Some(81490), None),
447 /// Allow negative trait implementations.
448 (active, negative_impls, "1.44.0", Some(68318), None),
449 /// Allows the `!` type. Does not imply 'exhaustive_patterns' (below) any more.
450 (active, never_type, "1.13.0", Some(35121), None),
451 /// Allows diverging expressions to fall back to `!` rather than `()`.
452 (active, never_type_fallback, "1.41.0", Some(65992), None),
453 /// Allows using non lexical lifetimes (RFC 2094).
454 (active, nll, "1.0.0", Some(43234), None),
455 /// Allows `#![no_core]`.
456 (active, no_core, "1.3.0", Some(29639), None),
457 /// Allows function attribute `#[no_coverage]`, to bypass coverage
458 /// instrumentation of that function.
459 (active, no_coverage, "1.53.0", Some(84605), None),
460 /// Allows the use of `no_sanitize` attribute.
461 (active, no_sanitize, "1.42.0", Some(39699), None),
462 /// Allows using the `non_exhaustive_omitted_patterns` lint.
463 (active, non_exhaustive_omitted_patterns_lint, "1.57.0", Some(89554), None),
464 /// Allows making `dyn Trait` well-formed even if `Trait` is not object safe.
465 /// In that case, `dyn Trait: Trait` does not hold. Moreover, coercions and
466 /// casts in safe Rust to `dyn Trait` for such a `Trait` is also forbidden.
467 (active, object_safe_for_dispatch, "1.40.0", Some(43561), None),
468 /// Allows using `#[optimize(X)]`.
469 (active, optimize_attribute, "1.34.0", Some(54882), None),
470 /// Allows `extern "platform-intrinsic" { ... }`.
471 (active, platform_intrinsics, "1.4.0", Some(27731), None),
472 /// Allows using `#![plugin(myplugin)]`.
473 (active, plugin, "1.0.0", Some(29597), None),
474 /// Allows exhaustive integer pattern matching on `usize` and `isize`.
475 (active, precise_pointer_size_matching, "1.32.0", Some(56354), None),
476 /// Allows macro attributes on expressions, statements and non-inline modules.
477 (active, proc_macro_hygiene, "1.30.0", Some(54727), None),
478 /// Allows the use of raw-dylibs (RFC 2627).
479 (incomplete, raw_dylib, "1.40.0", Some(58713), None),
480 /// Allows `&raw const $place_expr` and `&raw mut $place_expr` expressions.
481 (active, raw_ref_op, "1.41.0", Some(64490), None),
482 /// Allows using the `#[register_attr]` attribute.
483 (active, register_attr, "1.41.0", Some(66080), None),
484 /// Allows using the `#[register_tool]` attribute.
485 (active, register_tool, "1.41.0", Some(66079), None),
486 /// Allows the `#[repr(i128)]` attribute for enums.
487 (incomplete, repr128, "1.16.0", Some(56071), None),
488 /// Allows `repr(simd)` and importing the various simd intrinsics.
489 (active, repr_simd, "1.4.0", Some(27731), None),
490 /// Allows the use of SIMD types in functions declared in `extern` blocks.
491 (active, simd_ffi, "1.0.0", Some(27731), None),
492 /// Allows specialization of implementations (RFC 1210).
493 (incomplete, specialization, "1.7.0", Some(31844), None),
494 /// Allows `#[link(kind="static-nobundle"...)]`.
495 (active, static_nobundle, "1.16.0", Some(37403), None),
496 /// Allows attributes on expressions and non-item statements.
497 (active, stmt_expr_attributes, "1.6.0", Some(15701), None),
498 /// Allows the use of `#[target_feature]` on safe functions.
499 (active, target_feature_11, "1.45.0", Some(69098), None),
500 /// Allows using `#[thread_local]` on `static` items.
501 (active, thread_local, "1.0.0", Some(29594), None),
502 /// Allows defining `trait X = A + B;` alias items.
503 (active, trait_alias, "1.24.0", Some(41517), None),
504 /// Allows upcasting trait objects via supertraits.
505 /// Trait upcasting is casting, e.g., `dyn Foo -> dyn Bar` where `Foo: Bar`.
506 (incomplete, trait_upcasting, "1.56.0", Some(65991), None),
507 /// Allows #[repr(transparent)] on unions (RFC 2645).
508 (active, transparent_unions, "1.37.0", Some(60405), None),
509 /// Allows inconsistent bounds in where clauses.
510 (active, trivial_bounds, "1.28.0", Some(48214), None),
511 /// Allows using `try {...}` expressions.
512 (active, try_blocks, "1.29.0", Some(31436), None),
513 /// Allows `impl Trait` to be used inside type aliases (RFC 2515).
514 (active, type_alias_impl_trait, "1.38.0", Some(63063), None),
515 /// Allows the use of type ascription in expressions.
516 (active, type_ascription, "1.6.0", Some(23416), None),
517 /// Allows creation of instances of a struct by moving fields that have
518 /// not changed from prior instances of the same struct (RFC #2528)
519 (incomplete, type_changing_struct_update, "1.58.0", Some(86555), None),
520 /// Allows unsized fn parameters.
521 (active, unsized_fn_params, "1.49.0", Some(48055), None),
522 /// Allows unsized rvalues at arguments and parameters.
523 (incomplete, unsized_locals, "1.30.0", Some(48055), None),
524 /// Allows unsized tuple coercion.
525 (active, unsized_tuple_coercion, "1.20.0", Some(42877), None),
526 /// Allows `union`s to implement `Drop`. Moreover, `union`s may now include fields
527 /// that don't implement `Copy` as long as they don't have any drop glue.
528 /// This is checked recursively. On encountering type variable where no progress can be made,
529 /// `T: Copy` is used as a substitute for "no drop glue".
531 /// NOTE: A limited form of `union U { ... }` was accepted in 1.19.0.
532 (active, untagged_unions, "1.13.0", Some(55149), None),
533 /// Allows `extern "wasm" fn`
534 (active, wasm_abi, "1.53.0", Some(83788), None),
535 // !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
536 // Features are listed in alphabetical order. Tidy will fail if you don't keep it this way.
537 // !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!! !!!!
539 // -------------------------------------------------------------------------
540 // feature-group-end: actual feature gates
541 // -------------------------------------------------------------------------
544 /// Some features are not allowed to be used together at the same time, if
545 /// the two are present, produce an error.
547 /// Currently empty, but we will probably need this again in the future,
548 /// so let's keep it in for now.
549 pub const INCOMPATIBLE_FEATURES: &[(Symbol, Symbol)] = &[];