Struct Features

pub struct Features {
    enabled_lang_features: Vec<EnabledLangFeature>,
    enabled_lib_features: Vec<EnabledLibFeature>,
    enabled_features: FxHashSet<Symbol>,
}

A set of features to be used by later passes.

There are two ways to check if a language feature foo is enabled:

• Directly with the foo method, e.g. if tcx.features().foo() { ... }.
• With the enabled method, e.g. if tcx.features.enabled(sym::foo) { ... }.

The former is preferred. enabled should only be used when the feature symbol is not a constant, e.g. a parameter, or when the feature is a library feature.

Fields

enabled_lang_features: Vec<EnabledLangFeature>

#![feature] attrs for language features, for error reporting.

enabled_lib_features: Vec<EnabledLibFeature>

#![feature] attrs for non-language (library) features.

enabled_features: FxHashSet<Symbol>

enabled_lang_features + enabled_lib_features.

Implementations

impl Features

pub fn set_enabled_lang_feature(&mut self, lang_feat: EnabledLangFeature)

since should be set for stable features that are nevertheless enabled with a #[feature] attribute, indicating since when they are stable.

pub fn set_enabled_lib_feature(&mut self, lib_feat: EnabledLibFeature)

pub fn enabled_lang_features(&self) -> &Vec<EnabledLangFeature>

Returns a list of EnabledLangFeature with info about:

• Feature gate name.
• The span of the #[feature] attribute.
• For stable language features, version info for when it was stabilized.

pub fn enabled_lib_features(&self) -> &Vec<EnabledLibFeature>

pub fn enabled_features(&self) -> &FxHashSet<Symbol>

pub fn enabled(&self, feature: Symbol) -> bool

Is the given feature enabled (via #[feature(...)])?

impl Features

pub fn abi_unadjusted(&self) -> bool

pub fn allocator_internals(&self) -> bool

pub fn allow_internal_unsafe(&self) -> bool

pub fn allow_internal_unstable(&self) -> bool

pub fn anonymous_lifetime_in_impl_trait(&self) -> bool

pub fn compiler_builtins(&self) -> bool

pub fn custom_mir(&self) -> bool

pub fn generic_assert(&self) -> bool

pub fn intrinsics(&self) -> bool

pub fn lang_items(&self) -> bool

pub fn lifetime_capture_rules_2024(&self) -> bool

pub fn link_cfg(&self) -> bool

pub fn more_maybe_bounds(&self) -> bool

pub fn multiple_supertrait_upcastable(&self) -> bool

pub fn negative_bounds(&self) -> bool

pub fn omit_gdb_pretty_printer_section(&self) -> bool

pub fn pattern_complexity(&self) -> bool

pub fn pattern_types(&self) -> bool

pub fn prelude_import(&self) -> bool

pub fn profiler_runtime(&self) -> bool

pub fn rustc_attrs(&self) -> bool

pub fn staged_api(&self) -> bool

pub fn test_unstable_lint(&self) -> bool

pub fn unqualified_local_imports(&self) -> bool

pub fn with_negative_coherence(&self) -> bool

pub fn abi_vectorcall(&self) -> bool

pub fn auto_traits(&self) -> bool

pub fn box_patterns(&self) -> bool

pub fn builtin_syntax(&self) -> bool

pub fn doc_notable_trait(&self) -> bool

pub fn dropck_eyepatch(&self) -> bool

pub fn dyn_compatible_for_dispatch(&self) -> bool

pub fn fundamental(&self) -> bool

pub fn link_llvm_intrinsics(&self) -> bool

pub fn linkage(&self) -> bool

pub fn needs_panic_runtime(&self) -> bool

pub fn panic_runtime(&self) -> bool

pub fn rustc_allow_const_fn_unstable(&self) -> bool

pub fn rustc_private(&self) -> bool

pub fn rustdoc_internals(&self) -> bool

pub fn rustdoc_missing_doc_code_examples(&self) -> bool

pub fn start(&self) -> bool

pub fn structural_match(&self) -> bool

pub fn unboxed_closures(&self) -> bool

pub fn aarch64_unstable_target_feature(&self) -> bool

pub fn aarch64_ver_target_feature(&self) -> bool

pub fn arm_target_feature(&self) -> bool

pub fn avx512_target_feature(&self) -> bool

pub fn bpf_target_feature(&self) -> bool

pub fn csky_target_feature(&self) -> bool

pub fn ermsb_target_feature(&self) -> bool

pub fn hexagon_target_feature(&self) -> bool

pub fn lahfsahf_target_feature(&self) -> bool

pub fn loongarch_target_feature(&self) -> bool

pub fn m68k_target_feature(&self) -> bool

pub fn mips_target_feature(&self) -> bool

pub fn powerpc_target_feature(&self) -> bool

pub fn prfchw_target_feature(&self) -> bool

pub fn riscv_target_feature(&self) -> bool

pub fn rtm_target_feature(&self) -> bool

pub fn s390x_target_feature(&self) -> bool

pub fn sparc_target_feature(&self) -> bool

pub fn sse4a_target_feature(&self) -> bool

pub fn tbm_target_feature(&self) -> bool

pub fn wasm_target_feature(&self) -> bool

pub fn x87_target_feature(&self) -> bool

pub fn abi_avr_interrupt(&self) -> bool

pub fn abi_c_cmse_nonsecure_call(&self) -> bool

pub fn abi_msp430_interrupt(&self) -> bool

pub fn abi_ptx(&self) -> bool

pub fn abi_riscv_interrupt(&self) -> bool

pub fn abi_x86_interrupt(&self) -> bool

pub fn adt_const_params(&self) -> bool

pub fn alloc_error_handler(&self) -> bool

pub fn arbitrary_self_types(&self) -> bool

pub fn arbitrary_self_types_pointers(&self) -> bool

pub fn asm_experimental_arch(&self) -> bool

pub fn asm_experimental_reg(&self) -> bool

pub fn asm_goto(&self) -> bool

pub fn asm_goto_with_outputs(&self) -> bool

pub fn asm_unwind(&self) -> bool

pub fn associated_const_equality(&self) -> bool

pub fn associated_type_defaults(&self) -> bool

pub fn async_fn_in_dyn_trait(&self) -> bool

pub fn async_fn_track_caller(&self) -> bool

pub fn async_for_loop(&self) -> bool

pub fn async_trait_bounds(&self) -> bool

pub fn c_variadic(&self) -> bool

pub fn cfg_boolean_literals(&self) -> bool

pub fn cfg_overflow_checks(&self) -> bool

pub fn cfg_relocation_model(&self) -> bool

pub fn cfg_sanitize(&self) -> bool

pub fn cfg_sanitizer_cfi(&self) -> bool

pub fn cfg_target_compact(&self) -> bool

pub fn cfg_target_has_atomic(&self) -> bool

pub fn cfg_target_has_atomic_equal_alignment(&self) -> bool

pub fn cfg_target_thread_local(&self) -> bool

pub fn cfg_ub_checks(&self) -> bool

pub fn cfg_version(&self) -> bool

pub fn cfi_encoding(&self) -> bool

pub fn closure_lifetime_binder(&self) -> bool

pub fn closure_track_caller(&self) -> bool

pub fn cmse_nonsecure_entry(&self) -> bool

pub fn const_async_blocks(&self) -> bool

pub fn const_closures(&self) -> bool

pub fn const_destruct(&self) -> bool

pub fn const_for(&self) -> bool

pub fn const_precise_live_drops(&self) -> bool

pub fn const_trait_impl(&self) -> bool

pub fn const_try(&self) -> bool

pub fn coroutine_clone(&self) -> bool

pub fn coroutines(&self) -> bool

pub fn custom_inner_attributes(&self) -> bool

pub fn custom_test_frameworks(&self) -> bool

pub fn decl_macro(&self) -> bool

pub fn default_field_values(&self) -> bool

pub fn deprecated_safe(&self) -> bool

pub fn deprecated_suggestion(&self) -> bool

pub fn deref_patterns(&self) -> bool

pub fn doc_auto_cfg(&self) -> bool

pub fn doc_cfg(&self) -> bool

pub fn doc_cfg_hide(&self) -> bool

pub fn doc_masked(&self) -> bool

pub fn dyn_star(&self) -> bool

pub fn exhaustive_patterns(&self) -> bool

pub fn explicit_tail_calls(&self) -> bool

pub fn extern_types(&self) -> bool

pub fn f128(&self) -> bool

pub fn f16(&self) -> bool

pub fn ffi_const(&self) -> bool

pub fn ffi_pure(&self) -> bool

pub fn fmt_debug(&self) -> bool

pub fn fn_align(&self) -> bool

pub fn fn_delegation(&self) -> bool

pub fn freeze_impls(&self) -> bool

pub fn gen_blocks(&self) -> bool

pub fn generic_arg_infer(&self) -> bool

pub fn generic_const_exprs(&self) -> bool

pub fn generic_const_items(&self) -> bool

pub fn global_registration(&self) -> bool

pub fn guard_patterns(&self) -> bool

pub fn half_open_range_patterns_in_slices(&self) -> bool

pub fn if_let_guard(&self) -> bool

pub fn impl_trait_in_assoc_type(&self) -> bool

pub fn impl_trait_in_bindings(&self) -> bool

pub fn impl_trait_in_fn_trait_return(&self) -> bool

pub fn inherent_associated_types(&self) -> bool

pub fn inline_const_pat(&self) -> bool

pub fn intra_doc_pointers(&self) -> bool

pub fn large_assignments(&self) -> bool

pub fn lazy_type_alias(&self) -> bool

pub fn let_chains(&self) -> bool

pub fn link_arg_attribute(&self) -> bool

pub fn macro_metavar_expr(&self) -> bool

pub fn macro_metavar_expr_concat(&self) -> bool

pub fn marker_trait_attr(&self) -> bool

pub fn min_generic_const_args(&self) -> bool

pub fn min_specialization(&self) -> bool

pub fn more_qualified_paths(&self) -> bool

pub fn must_not_suspend(&self) -> bool

pub fn mut_ref(&self) -> bool

pub fn naked_functions(&self) -> bool

pub fn native_link_modifiers_as_needed(&self) -> bool

pub fn negative_impls(&self) -> bool

pub fn never_patterns(&self) -> bool

pub fn never_type(&self) -> bool

pub fn never_type_fallback(&self) -> bool

pub fn no_core(&self) -> bool

pub fn no_sanitize(&self) -> bool

pub fn non_exhaustive_omitted_patterns_lint(&self) -> bool

pub fn non_lifetime_binders(&self) -> bool

pub fn offset_of_enum(&self) -> bool

pub fn offset_of_slice(&self) -> bool

pub fn optimize_attribute(&self) -> bool

pub fn patchable_function_entry(&self) -> bool

pub fn pin_ergonomics(&self) -> bool

pub fn postfix_match(&self) -> bool

pub fn precise_capturing_in_traits(&self) -> bool

pub fn proc_macro_hygiene(&self) -> bool

pub fn ref_pat_eat_one_layer_2024(&self) -> bool

pub fn ref_pat_eat_one_layer_2024_structural(&self) -> bool

pub fn register_tool(&self) -> bool

pub fn repr128(&self) -> bool

pub fn repr_simd(&self) -> bool

pub fn return_type_notation(&self) -> bool

pub fn rust_cold_cc(&self) -> bool

pub fn sha512_sm_x86(&self) -> bool

pub fn simd_ffi(&self) -> bool

pub fn specialization(&self) -> bool

pub fn stmt_expr_attributes(&self) -> bool

pub fn strict_provenance_lints(&self) -> bool

pub fn string_deref_patterns(&self) -> bool

pub fn target_feature_11(&self) -> bool

pub fn thread_local(&self) -> bool

pub fn trait_alias(&self) -> bool

pub fn trait_upcasting(&self) -> bool

pub fn transmute_generic_consts(&self) -> bool

pub fn transparent_unions(&self) -> bool

pub fn trivial_bounds(&self) -> bool

pub fn try_blocks(&self) -> bool

pub fn type_alias_impl_trait(&self) -> bool

pub fn type_changing_struct_update(&self) -> bool

pub fn unsafe_binders(&self) -> bool

pub fn unsafe_fields(&self) -> bool

pub fn unsized_const_params(&self) -> bool

pub fn unsized_fn_params(&self) -> bool

pub fn unsized_locals(&self) -> bool

pub fn unsized_tuple_coercion(&self) -> bool

pub fn used_with_arg(&self) -> bool

pub fn x86_amx_intrinsics(&self) -> bool

pub fn xop_target_feature(&self) -> bool

pub fn yeet_expr(&self) -> bool

pub fn incomplete(&self, feature: Symbol) -> bool

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 fn internal(&self, feature: Symbol) -> bool

Some features are internal to the compiler and standard library and should not be used in normal projects. We warn the user about these to alert them.

impl Features

pub fn dump_feature_usage_metrics( &self, metrics_path: PathBuf, ) -> Result<(), Box<dyn Error>>

Trait Implementations

impl Clone for Features

fn clone(&self) -> Features

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Features

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Features

fn default() -> Features

Returns the “default value” for a type.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 80 bytes