Cleanup 'active' declare_features! with uniform style + sorting.

2 files changed, 268 insertions, 193 deletions

diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index dcec646fa22..65624f0b317 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -108,124 +108,227 @@ macro_rules! declare_features {
 // was set. This is most important for knowing when a particular feature became
 // stable (active).
 //
+// Note that the features should be grouped into internal/user-facing
+// and then sorted by version inside those groups.
+// FIXME(60361): Enforce ^-- with tidy.
+//
 // N.B., `tools/tidy/src/features.rs` parses this information directly out of the
 // source, so take care when modifying it.
 
 declare_features! (
-    (active, asm, "1.0.0", Some(29722), None),
-    (active, concat_idents, "1.0.0", Some(29599), None),
-    (active, link_args, "1.0.0", Some(29596), None),
-    (active, log_syntax, "1.0.0", Some(29598), None),
-    (active, non_ascii_idents, "1.0.0", Some(55467), None),
-    (active, plugin_registrar, "1.0.0", Some(29597), None),
-    (active, thread_local, "1.0.0", Some(29594), None),
-    (active, trace_macros, "1.0.0", Some(29598), None),
+    // -------------------------------------------------------------------------
+    // Internal feature gates.
+    // -------------------------------------------------------------------------
 
-    // rustc internal, for now
+    // no tracking issue START
+
+    // 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),
-    (active, format_args_nl, "1.29.0", None, None),
 
-    (active, link_llvm_intrinsics, "1.0.0", Some(29602), None),
-    (active, linkage, "1.0.0", Some(29603), None),
+    // Allows using the `#[stable]` and `#[unstable]` attributes.
+    (active, staged_api, "1.0.0", None, None),
 
-    // rustc internal
+    // 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),
+
+    // Allows using the macros:
+    // + `__diagnostic_used`
+    // + `__register_diagnostic`
+    // +`__build_diagnostic_array`
     (active, rustc_diagnostic_macros, "1.0.0", None, None),
+
+    // Allows using `#[rustc_const_unstable(feature = "foo", ..)]` which
+    // lets a function to be `const` when opted into with `#![feature(foo)]`.
     (active, rustc_const_unstable, "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 `rustc_*` attributes (RFC 572).
+    (active, rustc_attrs, "1.0.0", Some(29642), None),
+
+    // Allows using `#[on_unimplemented(..)]` on traits.
+    (active, on_unimplemented, "1.0.0", Some(29628), None),
+
+    // Allows using the `box $expr` syntax.
     (active, box_syntax, "1.0.0", Some(49733), None),
-    (active, unboxed_closures, "1.0.0", Some(29625), None),
 
-    (active, fundamental, "1.0.0", Some(29635), None),
+    // Allows using `#[main]` to replace the entrypoint `#[lang = "start"]` calls.
     (active, main, "1.0.0", Some(29634), None),
-    (active, needs_allocator, "1.4.0", Some(27389), None),
-    (active, on_unimplemented, "1.0.0", Some(29628), None),
-    (active, plugin, "1.0.0", Some(29597), None),
-    (active, simd_ffi, "1.0.0", Some(27731), None),
+
+    // Allows using `#[start]` on a function indicating that it is the program entrypoint.
     (active, start, "1.0.0", Some(29633), None),
-    (active, structural_match, "1.8.0", Some(31434), None),
-    (active, panic_runtime, "1.10.0", Some(32837), None),
-    (active, needs_panic_runtime, "1.10.0", Some(32837), None),
 
-    // Features specific to OIBIT (auto traits)
-    (active, optin_builtin_traits, "1.0.0", Some(13231), None),
+    // Allows using the `#[fundamental]` attribute.
+    (active, fundamental, "1.0.0", Some(29635), None),
 
-    // Allows `#[staged_api]`.
-    //
-    // rustc internal
-    (active, staged_api, "1.0.0", None, None),
+    // Allows using the `rust-call` ABI.
+    (active, unboxed_closures, "1.0.0", Some(29625), None),
 
-    // Allows `#![no_core]`.
-    (active, no_core, "1.3.0", Some(29639), 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 the use of `box` in patterns (RFC 469).
+    // Allows using `box` in patterns (RFC 469).
     (active, box_patterns, "1.0.0", Some(29641), None),
 
-    // Allows the use of the `unsafe_destructor_blind_to_params` attribute (RFC 1238).
+    // no tracking issue START
+
+    // Allows using `#[prelude_import]` on glob `use` items.
+    (active, prelude_import, "1.2.0", None, None),
+
+    // no tracking issue END
+
+    // Allows using `#[unsafe_destructor_blind_to_params]` (RFC 1238).
     (active, dropck_parametricity, "1.3.0", Some(28498), None),
 
+    // FIXME(Centril): Investigate whether this gate actually has any effect.
+    (active, needs_allocator, "1.4.0", Some(27389), None),
+
+    // 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 the `may_dangle` attribute (RFC 1327).
     (active, dropck_eyepatch, "1.10.0", Some(34761), None),
 
-    // Allows the use of custom attributes (RFC 572).
-    (active, custom_attribute, "1.0.0", Some(29642), None),
+    // Allows using `#[structural_match]` which indicates that a type is structurally matchable.
+    (active, structural_match, "1.8.0", Some(31434), None),
 
-    // Allows the use of `rustc_*` attributes (RFC 572).
-    (active, rustc_attrs, "1.0.0", Some(29642), None),
+    // Allows using the `#![panic_runtime]` attribute.
+    (active, panic_runtime, "1.10.0", Some(32837), None),
 
-    // Allows the use of non lexical lifetimes (RFC 2094).
-    (active, nll, "1.0.0", Some(43234), None),
+    // Allows declaring with `#![needs_panic_runtime]` that a panic runtime is needed.
+    (active, needs_panic_runtime, "1.10.0", Some(32837), None),
 
-    // Allows the use of `#[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).
-    //
-    // rustc internal
-    (active, allow_internal_unstable, "1.0.0", None, None),
+    // no tracking issue START
 
-    // Allows the use of `#[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).
-    //
-    // rustc internal
-    (active, allow_internal_unsafe, "1.0.0", None, None),
+    // Allows identifying the `compiler_builtins` crate.
+    (active, compiler_builtins, "1.13.0", None, None),
 
-    // Allows the use of slice patterns (issue #23121).
-    (active, slice_patterns, "1.0.0", Some(23121), None),
+    // Allows using the `unadjusted` ABI; perma-unstable.
+    (active, abi_unadjusted, "1.16.0", None, None),
 
-    // Allows the definition of `const` functions with some advanced features.
-    (active, const_fn, "1.2.0", Some(57563), None),
+    // Allows identifying crates that contain sanitizer runtimes.
+    (active, sanitizer_runtime, "1.17.0", None, None),
 
-    // Allows accessing fields of unions inside `const` functions.
-    (active, const_fn_union, "1.27.0", Some(51909), None),
+    // Used to identify crates that contain the profiler runtime.
+    (active, profiler_runtime, "1.18.0", None, None),
 
-    // Allows casting raw pointers to `usize` during const eval.
-    (active, const_raw_ptr_to_usize_cast, "1.27.0", Some(51910), None),
+    // Allows using the `thiscall` ABI.
+    (active, abi_thiscall, "1.19.0", None, None),
 
-    // Allows dereferencing raw pointers during const eval.
-    (active, const_raw_ptr_deref, "1.27.0", Some(51911), None),
+    // Allows using `#![needs_allocator]`, an implementation detail of `#[global_allocator]`.
+    (active, allocator_internals, "1.20.0", None, None),
 
-    // Allows reinterpretation of the bits of a value of one type as another type during const eval.
-    (active, const_transmute, "1.29.0", Some(53605), None),
+    // Allows using the `format_args_nl` macro.
+    (active, format_args_nl, "1.29.0", None, None),
 
-    // Allows comparing raw pointers during const eval.
-    (active, const_compare_raw_pointers, "1.27.0", Some(53020), None),
+    // no tracking issue END
 
-    // Allows panicking during const eval (producing compile-time errors).
-    (active, const_panic, "1.30.0", Some(51999), None),
+    // Added for testing E0705; perma-unstable.
+    (active, test_2018_feature, "1.31.0", Some(0), Some(Edition::Edition2018)),
 
-    // Allows using `#[prelude_import]` on glob `use` items.
-    //
-    // rustc internal
-    (active, prelude_import, "1.2.0", None, None),
+    // -------------------------------------------------------------------------
+    // Actual feature gates (target features).
+    // -------------------------------------------------------------------------
 
-    // Allows default type parameters to influence type inference.
-    (active, default_type_parameter_fallback, "1.3.0", Some(27336), None),
+    // 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),
+
+    // -------------------------------------------------------------------------
+    // Actual feature gates.
+    // -------------------------------------------------------------------------
+
+    // Allows using `asm!` macro with which inline assembly can be embedded.
+    (active, asm, "1.0.0", Some(29722), None),
+
+    // Allows using the `concat_idents!` macro with which identifiers can be concatenated.
+    (active, concat_idents, "1.0.0", Some(29599), None),
+
+    // 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 using the `log_syntax!` macro.
+    (active, log_syntax, "1.0.0", Some(29598), None),
+
+    // Allows using the `trace_macros!` macro.
+    (active, trace_macros, "1.0.0", Some(29598), None),
+
+    // Allows the use of SIMD types in functions declared in `extern` blocks.
+    (active, simd_ffi, "1.0.0", Some(27731), None),
+
+    // Allows using custom attributes (RFC 572).
+    (active, custom_attribute, "1.0.0", Some(29642), None),
+
+    // Allows using non lexical lifetimes (RFC 2094).
+    (active, nll, "1.0.0", Some(43234), None),
+
+    // Allows using slice patterns.
+    (active, slice_patterns, "1.0.0", Some(23121), 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),
 
@@ -237,17 +340,12 @@ declare_features! (
     // Permits specifying whether a function should permit unwinding or abort on unwind.
     (active, unwind_attributes, "1.4.0", Some(58760), None),
 
-    // Allows the use of `#[naked]` on functions.
+    // Allows using `#[naked]` on functions.
     (active, naked_functions, "1.9.0", Some(32408), None),
 
     // Allows `#[no_debug]`.
     (active, no_debug, "1.5.0", Some(29721), None),
 
-    // Allows `#[omit_gdb_pretty_printer_section]`.
-    //
-    // rustc internal
-    (active, omit_gdb_pretty_printer_section, "1.5.0", None, None),
-
     // Allows attributes on expressions and non-item statements.
     (active, stmt_expr_attributes, "1.6.0", Some(15701), None),
 
@@ -257,19 +355,16 @@ declare_features! (
     // Allows `cfg(target_thread_local)`.
     (active, cfg_target_thread_local, "1.7.0", Some(29594), None),
 
-    // rustc internal
-    (active, abi_vectorcall, "1.7.0", None, None),
-
-    // Allows `X..Y` patterns.
-    (active, exclusive_range_pattern, "1.11.0", Some(37854), None),
-
-    // impl specialization (RFC 1210)
+    // Allows specialization of implementations (RFC 1210).
     (active, specialization, "1.7.0", Some(31844), None),
 
     // Allows `cfg(target_has_atomic = "...")`.
     (active, cfg_target_has_atomic, "1.9.0", Some(32976), None),
 
-    // The `!` type. Does not imply 'exhaustive_patterns' (below) any more.
+    // 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.
@@ -278,175 +373,143 @@ declare_features! (
     // Allows untagged unions `union U { ... }`.
     (active, untagged_unions, "1.13.0", Some(32836), None),
 
-    // Used to identify the `compiler_builtins` crate.
-    //
-    // rustc internal.
-    (active, compiler_builtins, "1.13.0", None, 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),
 
-    // The `repr(i128)` annotation for enums.
+    // Allows the `#[repr(i128)]` attribute for enums.
     (active, repr128, "1.16.0", Some(35118), None),
 
-    // Allows the use of `#[ffi_returns_twice]` on foreign functions.
-    (active, ffi_returns_twice, "1.34.0", Some(58314), None),
-
-    // The `unadjusted` ABI; perma-unstable.
-    //
-    // rustc internal
-    (active, abi_unadjusted, "1.16.0", None, None),
-
-    // Declarative macros 2.0 (`macro`).
-    (active, decl_macro, "1.17.0", Some(39412), 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),
 
-    // Used to identify crates that contain sanitizer runtimes.
-    //
-    // rustc internal
-    (active, sanitizer_runtime, "1.17.0", None, None),
-
-    // Used to identify crates that contain the profiler runtime.
-    //
-    // rustc internal
-    (active, profiler_runtime, "1.18.0", None, 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 the `try {...}` expression.
-    (active, try_blocks, "1.29.0", Some(31436), None),
-
     // Allows module-level inline assembly by way of `global_asm!()`.
     (active, global_asm, "1.18.0", Some(35119), None),
 
     // Allows overlapping impls of marker traits.
     (active, overlapping_marker_traits, "1.18.0", Some(29864), None),
 
-    // Trait attribute to allow overlapping impls.
-    (active, marker_trait_attr, "1.30.0", Some(29864), None),
-
-    // rustc internal
-    (active, abi_thiscall, "1.19.0", None, 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),
 
-    // Generators
+    // Allows defining generators.
     (active, generators, "1.21.0", Some(43122), None),
 
-    // Trait aliases
-    (active, trait_alias, "1.24.0", Some(41517), None),
-
-    // rustc internal
-    (active, allocator_internals, "1.20.0", None, None),
-
-    // `#[doc(cfg(...))]`
+    // Allows `#[doc(cfg(...))]`.
     (active, doc_cfg, "1.21.0", Some(43781), None),
-    // `#[doc(masked)]`
+
+    // Allows `#[doc(masked)]`.
     (active, doc_masked, "1.21.0", Some(44027), None),
-    // `#[doc(spotlight)]`
+
+    // Allows `#[doc(spotlight)]`.
     (active, doc_spotlight, "1.22.0", Some(45040), None),
-    // `#[doc(include = "some-file")]`
+
+    // Allows `#[doc(include = "some-file")]`.
     (active, external_doc, "1.22.0", Some(44732), None),
 
-    // Future-proofing enums/structs with `#[non_exhaustive]` attribute (RFC 2008).
+    // Allows future-proofing enums/structs with the `#[non_exhaustive]` attribute (RFC 2008).
     (active, non_exhaustive, "1.22.0", Some(44109), None),
 
-    // Adds `crate` as visibility modifier, synonymous with `pub(crate)`.
+    // Allows using `crate` as visibility modifier, synonymous with `pub(crate)`.
     (active, crate_visibility_modifier, "1.23.0", Some(53120), None),
 
-    // extern types
+    // 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),
 
-    // In-band lifetime bindings (e.g., `fn foo(x: &'a u8) -> &'a u8`).
+    // 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),
 
-    // Generic associated types (RFC 1598)
+    // Allows associated types to be generic, e.g., `type Foo<T>;` (RFC 1598).
     (active, generic_associated_types, "1.23.0", Some(44265), None),
 
-    // Infer static outlives requirements (RFC 2093).
+    // Allows defining `trait X = A + B;` alias items.
+    (active, trait_alias, "1.24.0", Some(41517), None),
+
+    // Allows infering `'static` outlives requirements (RFC 2093).
     (active, infer_static_outlives_requirements, "1.26.0", Some(54185), None),
 
     // Allows macro invocations in `extern {}` blocks.
     (active, macros_in_extern, "1.27.0", Some(49476), None),
 
-    // `existential type`
-    (active, existential_type, "1.28.0", Some(34511), None),
+    // Allows accessing fields of unions inside `const` functions.
+    (active, const_fn_union, "1.27.0", Some(51909), None),
 
-    // 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),
+    // Allows casting raw pointers to `usize` during const eval.
+    (active, const_raw_ptr_to_usize_cast, "1.27.0", Some(51910), 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 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),
 
-    // `#[doc(alias = "...")]`
+    // Allows `#[doc(alias = "...")]`.
     (active, doc_alias, "1.27.0", Some(50146), None),
 
-    // inconsistent bounds in where clauses
+    // Allows defining `existential type`s.
+    (active, existential_type, "1.28.0", Some(34511), None),
+
+    // Allows inconsistent bounds in where clauses.
     (active, trivial_bounds, "1.28.0", Some(48214), None),
 
-    // `'a: { break 'a; }`
+    // Allows `'a: { break 'a; }`.
     (active, label_break_value, "1.28.0", Some(48594), None),
 
-    // Exhaustive pattern matching on `usize` and `isize`.
-    (active, precise_pointer_size_matching, "1.32.0", Some(56354), None),
-
-    // `#[doc(keyword = "...")]`
+    // Allows using `#[doc(keyword = "...")]`.
     (active, doc_keyword, "1.28.0", Some(51315), None),
 
     // Allows async and await syntax.
     (active, async_await, "1.28.0", Some(50547), None),
 
-    // `#[alloc_error_handler]`
+    // Allows reinterpretation of the bits of a value of one type as another type during const eval.
+    (active, const_transmute, "1.29.0", Some(53605), 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),
 
-    // Added for testing E0705; perma-unstable.
-    (active, test_2018_feature, "1.31.0", Some(0), Some(Edition::Edition2018)),
+    // 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),
 
-    // `#![test_runner]`
-    // `#[test_case]`
+    // Allows custom test frameworks with `#![test_runner]` and `#[test_case]`.
     (active, custom_test_frameworks, "1.30.0", Some(50297), None),
 
-    // non-builtin attributes in inner attribute position
+    // Allows non-builtin attributes in inner attribute position.
     (active, custom_inner_attributes, "1.30.0", Some(54726), None),
 
-    // Allow mixing of bind-by-move in patterns and references to
-    // those identifiers in guards.
+    // Allows mixing bind-by-move in patterns and references to those identifiers in guards.
     (active, bind_by_move_pattern_guards, "1.30.0", Some(15287), None),
 
     // Allows `impl Trait` in bindings (`let`, `const`, `static`).
@@ -455,25 +518,32 @@ declare_features! (
     // Allows `const _: TYPE = VALUE`.
     (active, underscore_const_names, "1.31.0", Some(54912), None),
 
-    // Adds `reason` and `expect` lint attributes.
+    // Allows using `reason` in lint attributes and the `#[expect(lint)]` lint check.
     (active, lint_reasons, "1.31.0", Some(54503), None),
 
     // Allows paths to enum variants on type aliases.
     (active, type_alias_enum_variants, "1.31.0", Some(49683), None),
 
-    // Re-Rebalance coherence
+    // Allows exhaustive integer pattern matching on `usize` and `isize`.
+    (active, precise_pointer_size_matching, "1.32.0", Some(56354), None),
+
+    // Allows relaxing the coherence rules such that
+    // `impl<T> ForeignTrait<LocalType> for ForeignType<T> is permitted.
     (active, re_rebalance_coherence, "1.32.0", Some(55437), None),
 
-    // Const generic types.
+    // 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),
 
-    // #[optimize(X)]
+    // Allows using `#[optimize(X)]`.
     (active, optimize_attribute, "1.34.0", Some(54882), None),
 
-    // #[repr(align(X))] on enums
+    // Allows using `#[repr(align(X))]` on enums.
     (active, repr_align_enum, "1.34.0", Some(57996), None),
 
-    // Allows the use of C-variadics
+    // Allows using C-variadics.
     (active, c_variadic, "1.34.0", Some(44930), None),
 );
 
@@ -499,7 +569,6 @@ declare_features! (
     (removed, visible_private_types, "1.0.0", None, None, None),
     (removed, unsafe_no_drop_flag, "1.0.0", None, None, None),
     // Allows using items which are missing stability attributes
-    // rustc internal
     (removed, unmarked_api, "1.0.0", None, None, None),
     (removed, pushpop_unsafe, "1.2.0", None, None, None),
     (removed, allocator, "1.0.0", None, None, None),
diff --git a/src/tools/tidy/src/features.rs b/src/tools/tidy/src/features.rs
index 1eab217027c..8239fd9dce0 100644
--- a/src/tools/tidy/src/features.rs
+++ b/src/tools/tidy/src/features.rs
@@ -173,18 +173,25 @@ pub fn collect_lang_features(base_src_path: &Path, bad: &mut bool) -> Features {
     let contents = t!(fs::read_to_string(base_src_path.join("libsyntax/feature_gate.rs")));
 
     // We allow rustc-internal features to omit a tracking issue.
-    // These features must be marked with a `// rustc internal` in its own group.
-    let mut next_feature_is_rustc_internal = false;
+    // To make tidy accept omitting a tracking issue, group the list of features
+    // without one inside `// no tracking issue START` and `// no tracking issue END`.
+    let mut next_feature_omits_tracking_issue = false;
 
     contents.lines().zip(1..)
         .filter_map(|(line, line_number)| {
             let line = line.trim();
-            if line.starts_with("// rustc internal") {
-                next_feature_is_rustc_internal = true;
-                return None;
-            } else if line.is_empty() {
-                next_feature_is_rustc_internal = false;
-                return None;
+
+            // Within START and END, the tracking issue can be omitted.
+            match line {
+                "// no tracking issue START" => {
+                    next_feature_omits_tracking_issue = true;
+                    return None;
+                }
+                "// no tracking issue END" => {
+                    next_feature_omits_tracking_issue = false;
+                    return None;
+                }
+                _ => {}
             }
 
             let mut parts = line.split(',');
@@ -198,7 +205,7 @@ pub fn collect_lang_features(base_src_path: &Path, bad: &mut bool) -> Features {
             let since = parts.next().unwrap().trim().trim_matches('"');
             let issue_str = parts.next().unwrap().trim();
             let tracking_issue = if issue_str.starts_with("None") {
-                if level == Status::Unstable && !next_feature_is_rustc_internal {
+                if level == Status::Unstable && !next_feature_omits_tracking_issue {
                     *bad = true;
                     tidy_error!(
                         bad,
@@ -209,7 +216,6 @@ pub fn collect_lang_features(base_src_path: &Path, bad: &mut bool) -> Features {
                 }
                 None
             } else {
-                next_feature_is_rustc_internal = false;
                 let s = issue_str.split('(').nth(1).unwrap().split(')').nth(0).unwrap();
                 Some(s.parse().unwrap())
             };