1 //! An "interner" is a data structure that associates values with usize tags and
2 //! allows bidirectional lookup; i.e., given a value, one can easily find the
3 //! type, and vice versa.
5 use rustc_arena::DroplessArena;
6 use rustc_data_structures::fx::FxHashMap;
7 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
8 use rustc_data_structures::sync::Lock;
9 use rustc_macros::HashStable_Generic;
10 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
12 use std::cmp::{Ord, PartialEq, PartialOrd};
14 use std::hash::{Hash, Hasher};
17 use crate::{with_session_globals, Edition, Span, DUMMY_SP};
22 // The proc macro code for this is in `compiler/rustc_macros/src/symbols.rs`.
24 // After modifying this list adjust `is_special`, `is_used_keyword`/`is_unused_keyword`,
25 // this should be rarely necessary though if the keywords are kept in alphabetic order.
27 // Special reserved identifiers used internally for elided lifetimes,
28 // unnamed method parameters, crate root module, error recovery etc.
31 DollarCrate: "$crate",
34 // Keywords that are used in stable Rust.
71 // Keywords that are used in unstable Rust or reserved for future use.
85 // Edition-specific keywords that are used in stable Rust.
86 Async: "async", // >= 2018 Edition only
87 Await: "await", // >= 2018 Edition only
88 Dyn: "dyn", // >= 2018 Edition only
90 // Edition-specific keywords that are used in unstable Rust or reserved for future use.
91 Try: "try", // >= 2018 Edition only
93 // Special lifetime names
94 UnderscoreLifetime: "'_",
95 StaticLifetime: "'static",
97 // Weak keywords, have special meaning only in specific contexts.
101 MacroRules: "macro_rules",
107 // Pre-interned symbols that can be referred to with `rustc_span::sym::*`.
109 // The symbol is the stringified identifier unless otherwise specified, in
110 // which case the name should mention the non-identifier punctuation.
111 // E.g. `sym::proc_dash_macro` represents "proc-macro", and it shouldn't be
112 // called `sym::proc_macro` because then it's easy to mistakenly think it
113 // represents "proc_macro".
115 // As well as the symbols listed, there are symbols for the strings
116 // "0", "1", ..., "9", which are accessible via `sym::integer`.
118 // The proc macro will abort if symbols are not in alphabetical order (as
119 // defined by `impl Ord for str`) or if any symbols are duplicated. Vim
120 // users can sort the list by selecting it and executing the command
121 // `:'<,'>!LC_ALL=C sort`.
123 // There is currently no checking that all symbols are used; that would be
245 ProceduralMasqueradeDummyType,
270 SubdiagnosticMessage,
300 aarch64_target_feature,
301 aarch64_ver_target_feature,
305 abi_c_cmse_nonsecure_call,
307 abi_msp430_interrupt,
321 advanced_slice_patterns,
337 allow_internal_unsafe,
338 allow_internal_unstable,
344 anonymous_lifetime_in_impl_trait,
347 arbitrary_enum_discriminant,
348 arbitrary_self_types,
360 asm_experimental_arch,
368 assert_receiver_is_total_eq,
372 associated_const_equality,
374 associated_type_bounds,
375 associated_type_defaults,
388 augmented_assignments,
390 automatically_derived,
392 avx512_target_feature,
400 bind_by_move_pattern_guards,
412 borrowck_graphviz_format,
413 borrowck_graphviz_postflow,
414 borrowck_graphviz_preflow,
419 braced_empty_structs,
431 capture_disjoint_fields,
448 cfg_target_has_atomic,
449 cfg_target_has_atomic_equal_alignment,
450 cfg_target_has_atomic_load_store,
451 cfg_target_thread_local,
463 closure_lifetime_binder,
464 closure_to_fn_coercion,
465 closure_track_caller,
469 cmpxchg16b_target_feature,
470 cmse_nonsecure_entry,
477 compare_exchange_weak,
487 conservative_impl_trait,
491 const_compare_raw_pointers,
496 const_eval_select_ct,
497 const_evaluatable_checked,
500 const_fn_floating_point_arithmetic,
501 const_fn_fn_ptr_basics,
502 const_fn_trait_bound,
508 const_generic_defaults,
510 const_generics_defaults,
513 const_in_array_repeat_expressions,
520 const_precise_live_drops,
522 const_raw_ptr_to_usize_cast,
525 const_trait_bound_opt_out,
542 core_panic_2015_macro,
553 crate_visibility_modifier,
554 crt_dash_static: "crt-static",
563 custom_inner_attributes,
564 custom_test_frameworks,
571 debug_assert_eq_macro,
573 debug_assert_ne_macro,
576 debug_struct_fields_finish,
579 debug_tuple_fields_finish,
584 default_alloc_error_handler,
585 default_lib_allocator,
586 default_method_body_is_const,
587 default_type_parameter_fallback,
589 delay_span_bug_from_inside_query,
593 deprecated_suggestion,
601 destructuring_assignment,
622 document_private_items,
624 dotdot_in_tuple_patterns,
625 dotdoteq_in_patterns,
633 dropck_parametricity,
644 emit_enum_variant_arg,
656 ermsb_target_feature,
660 exclusive_range_pattern,
661 exhaustive_integer_patterns,
670 explicit_generic_args_with_impl_trait,
673 extended_key_value_attributes,
674 extern_absolute_paths,
675 extern_crate_item_prelude,
698 field_init_shorthand,
705 float_to_int_unchecked,
738 from_size_align_unchecked,
755 generic_associated_types,
756 generic_associated_types_extended,
764 half_open_range_patterns,
766 hexagon_target_feature,
768 homogeneous_aggregate,
785 if_while_or_patterns,
787 impl_header_lifetime_elision,
790 impl_trait_in_bindings,
801 inclusive_range_syntax,
804 infer_outlives_requirements,
805 infer_static_outlives_requirements,
806 inherent_associated_types,
820 irrefutable_let_patterns,
824 issue_5723_bootstrap,
825 issue_tracker_base_url,
840 lazy_normalization_consts,
855 link_llvm_intrinsics,
876 macro_at_most_once_rep,
877 macro_attributes_in_derive_output,
880 macro_lifetime_matcher,
881 macro_literal_matcher,
894 match_beginning_vert,
895 match_default_bindings,
925 min_type_alias_impl_trait,
936 more_qualified_paths,
938 movbe_target_feature,
950 native_link_modifiers,
951 native_link_modifiers_as_needed,
952 native_link_modifiers_bundle,
953 native_link_modifiers_verbatim,
954 native_link_modifiers_whole_archive,
992 non_exhaustive_omitted_patterns_lint,
1004 object_safe_for_dispatch,
1007 omit_gdb_pretty_printer_section,
1016 optin_builtin_traits,
1025 overlapping_marker_traits,
1037 panic_implementation,
1052 pattern_parentheses,
1055 platform_intrinsics,
1064 post_dash_lto: "post-lto",
1065 powerpc_target_feature,
1070 pre_dash_lto: "pre-lto",
1071 precise_pointer_size_matching,
1075 prefetch_read_instruction,
1076 prefetch_write_data,
1077 prefetch_write_instruction,
1085 proc_dash_macro: "proc-macro",
1087 proc_macro_attribute,
1088 proc_macro_def_site,
1093 proc_macro_internals,
1095 proc_macro_non_items,
1096 proc_macro_path_invoc,
1105 ptr_offset_from_unsigned,
1113 quad_precision_float,
1116 range_inclusive_new,
1121 re_rebalance_coherence,
1124 read_enum_variant_arg,
1132 reexport_test_harness_main,
1133 ref_unwind_safe_trait,
1150 relaxed_struct_unsize,
1165 riscv_target_feature,
1184 rust_eh_catch_typeinfo,
1185 rust_eh_personality,
1186 rust_eh_register_frames,
1187 rust_eh_unregister_frames,
1191 rustc_allocator_nounwind,
1192 rustc_allow_const_fn_unstable,
1193 rustc_allow_incoherent_impl,
1194 rustc_allowed_through_unstable_modules,
1197 rustc_builtin_macro,
1198 rustc_capture_analysis,
1200 rustc_coherence_is_core,
1202 rustc_const_unstable,
1203 rustc_conversion_suggestion,
1205 rustc_diagnostic_item,
1206 rustc_diagnostic_macros,
1208 rustc_do_not_const_check,
1210 rustc_dump_env_program_clauses,
1211 rustc_dump_program_clauses,
1212 rustc_dump_user_substs,
1215 rustc_evaluate_where_clauses,
1216 rustc_expected_cgu_reuse,
1217 rustc_has_incoherent_inherent_impls,
1218 rustc_if_this_changed,
1219 rustc_inherit_overflow_checks,
1220 rustc_insignificant_dtor,
1222 rustc_layout_scalar_valid_range_end,
1223 rustc_layout_scalar_valid_range_start,
1224 rustc_legacy_const_generics,
1225 rustc_lint_diagnostics,
1226 rustc_lint_query_instability,
1227 rustc_macro_transparency,
1230 rustc_must_implement_one_of,
1231 rustc_nonnull_optimization_guaranteed,
1232 rustc_object_lifetime_default,
1233 rustc_on_unimplemented,
1236 rustc_partition_codegened,
1237 rustc_partition_reused,
1238 rustc_pass_by_value,
1240 rustc_peek_definite_init,
1241 rustc_peek_liveness,
1242 rustc_peek_maybe_init,
1243 rustc_peek_maybe_uninit,
1244 rustc_polymorphize_error,
1246 rustc_proc_macro_decls,
1249 rustc_reservation_impl,
1251 rustc_skip_array_during_method_dispatch,
1252 rustc_specialization_trait,
1254 rustc_std_internal_symbol,
1255 rustc_strict_coherence,
1258 rustc_then_this_would_need,
1259 rustc_trivial_field_reads,
1260 rustc_unsafe_specialization_marker,
1265 rvalue_static_promotion,
1316 simd_reduce_add_ordered,
1317 simd_reduce_add_unordered,
1322 simd_reduce_max_nanless,
1324 simd_reduce_min_nanless,
1325 simd_reduce_mul_ordered,
1326 simd_reduce_mul_unordered,
1331 simd_saturating_add,
1332 simd_saturating_sub,
1335 simd_select_bitmask,
1363 sse4a_target_feature,
1375 std_panic_2015_macro,
1378 stmt_expr_attributes,
1379 stop_after_dataflow,
1382 str_split_whitespace,
1389 struct_field_attributes,
1412 target_has_atomic_equal_alignment,
1413 target_has_atomic_load_store,
1415 target_pointer_width,
1416 target_target_vendor,
1417 target_thread_local,
1423 termination_trait_test,
1426 test_accepted_feature,
1428 test_removed_feature,
1436 thumb_mode: "thumb-mode",
1464 type_alias_enum_variants,
1465 type_alias_impl_trait,
1467 type_changing_struct_update,
1477 unaligned_volatile_load,
1478 unaligned_volatile_store,
1487 underscore_const_names,
1489 underscore_lifetimes,
1491 unimplemented_macro,
1493 universal_impl_trait,
1500 unreachable_2015_macro,
1502 unreachable_2021_macro,
1504 unreachable_display,
1506 unrestricted_attribute_tokens,
1507 unsafe_block_in_unsafe_fn,
1509 unsafe_no_drop_flag,
1510 unsafe_pin_internals,
1514 unsized_tuple_coercion,
1518 unused_qualifications,
1545 visible_private_types,
1547 volatile_copy_memory,
1548 volatile_copy_nonoverlapping_memory,
1550 volatile_set_memory,
1557 wasm_target_feature,
1562 with_negative_coherence,
1574 yeet_desugar_details,
1581 #[derive(Copy, Clone, Eq, HashStable_Generic, Encodable, Decodable)]
1589 /// Constructs a new identifier from a symbol and a span.
1590 pub const fn new(name: Symbol, span: Span) -> Ident {
1591 Ident { name, span }
1594 /// Constructs a new identifier with a dummy span.
1596 pub const fn with_dummy_span(name: Symbol) -> Ident {
1597 Ident::new(name, DUMMY_SP)
1601 pub fn empty() -> Ident {
1602 Ident::with_dummy_span(kw::Empty)
1605 /// Maps a string to an identifier with a dummy span.
1606 pub fn from_str(string: &str) -> Ident {
1607 Ident::with_dummy_span(Symbol::intern(string))
1610 /// Maps a string and a span to an identifier.
1611 pub fn from_str_and_span(string: &str, span: Span) -> Ident {
1612 Ident::new(Symbol::intern(string), span)
1615 /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
1616 pub fn with_span_pos(self, span: Span) -> Ident {
1617 Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
1620 pub fn without_first_quote(self) -> Ident {
1621 Ident::new(Symbol::intern(self.as_str().trim_start_matches('\'')), self.span)
1624 /// "Normalize" ident for use in comparisons using "item hygiene".
1625 /// Identifiers with same string value become same if they came from the same macro 2.0 macro
1626 /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
1627 /// different macro 2.0 macros.
1628 /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
1629 pub fn normalize_to_macros_2_0(self) -> Ident {
1630 Ident::new(self.name, self.span.normalize_to_macros_2_0())
1633 /// "Normalize" ident for use in comparisons using "local variable hygiene".
1634 /// Identifiers with same string value become same if they came from the same non-transparent
1635 /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
1636 /// non-transparent macros.
1637 /// Technically, this operation strips all transparent marks from ident's syntactic context.
1638 pub fn normalize_to_macro_rules(self) -> Ident {
1639 Ident::new(self.name, self.span.normalize_to_macro_rules())
1642 /// Access the underlying string. This is a slowish operation because it
1643 /// requires locking the symbol interner.
1645 /// Note that the lifetime of the return value is a lie. See
1646 /// `Symbol::as_str()` for details.
1647 pub fn as_str(&self) -> &str {
1652 impl PartialEq for Ident {
1653 fn eq(&self, rhs: &Self) -> bool {
1654 self.name == rhs.name && self.span.eq_ctxt(rhs.span)
1658 impl Hash for Ident {
1659 fn hash<H: Hasher>(&self, state: &mut H) {
1660 self.name.hash(state);
1661 self.span.ctxt().hash(state);
1665 impl fmt::Debug for Ident {
1666 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1667 fmt::Display::fmt(self, f)?;
1668 fmt::Debug::fmt(&self.span.ctxt(), f)
1672 /// This implementation is supposed to be used in error messages, so it's expected to be identical
1673 /// to printing the original identifier token written in source code (`token_to_string`),
1674 /// except that AST identifiers don't keep the rawness flag, so we have to guess it.
1675 impl fmt::Display for Ident {
1676 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1677 fmt::Display::fmt(&IdentPrinter::new(self.name, self.is_raw_guess(), None), f)
1681 /// This is the most general way to print identifiers.
1682 /// AST pretty-printer is used as a fallback for turning AST structures into token streams for
1683 /// proc macros. Additionally, proc macros may stringify their input and expect it survive the
1684 /// stringification (especially true for proc macro derives written between Rust 1.15 and 1.30).
1685 /// So we need to somehow pretty-print `$crate` in a way preserving at least some of its
1686 /// hygiene data, most importantly name of the crate it refers to.
1687 /// As a result we print `$crate` as `crate` if it refers to the local crate
1688 /// and as `::other_crate_name` if it refers to some other crate.
1689 /// Note, that this is only done if the ident token is printed from inside of AST pretty-printing,
1690 /// but not otherwise. Pretty-printing is the only way for proc macros to discover token contents,
1691 /// so we should not perform this lossy conversion if the top level call to the pretty-printer was
1692 /// done for a token stream or a single token.
1693 pub struct IdentPrinter {
1696 /// Span used for retrieving the crate name to which `$crate` refers to,
1697 /// if this field is `None` then the `$crate` conversion doesn't happen.
1698 convert_dollar_crate: Option<Span>,
1702 /// The most general `IdentPrinter` constructor. Do not use this.
1703 pub fn new(symbol: Symbol, is_raw: bool, convert_dollar_crate: Option<Span>) -> IdentPrinter {
1704 IdentPrinter { symbol, is_raw, convert_dollar_crate }
1707 /// This implementation is supposed to be used when printing identifiers
1708 /// as a part of pretty-printing for larger AST pieces.
1709 /// Do not use this either.
1710 pub fn for_ast_ident(ident: Ident, is_raw: bool) -> IdentPrinter {
1711 IdentPrinter::new(ident.name, is_raw, Some(ident.span))
1715 impl fmt::Display for IdentPrinter {
1716 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1719 } else if self.symbol == kw::DollarCrate {
1720 if let Some(span) = self.convert_dollar_crate {
1721 let converted = span.ctxt().dollar_crate_name();
1722 if !converted.is_path_segment_keyword() {
1725 return fmt::Display::fmt(&converted, f);
1728 fmt::Display::fmt(&self.symbol, f)
1732 /// An newtype around `Ident` that calls [Ident::normalize_to_macro_rules] on
1734 // FIXME(matthewj, petrochenkov) Use this more often, add a similar
1735 // `ModernIdent` struct and use that as well.
1736 #[derive(Copy, Clone, Eq, PartialEq, Hash)]
1737 pub struct MacroRulesNormalizedIdent(Ident);
1739 impl MacroRulesNormalizedIdent {
1740 pub fn new(ident: Ident) -> Self {
1741 Self(ident.normalize_to_macro_rules())
1745 impl fmt::Debug for MacroRulesNormalizedIdent {
1746 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1747 fmt::Debug::fmt(&self.0, f)
1751 impl fmt::Display for MacroRulesNormalizedIdent {
1752 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1753 fmt::Display::fmt(&self.0, f)
1757 /// An interned string.
1759 /// Internally, a `Symbol` is implemented as an index, and all operations
1760 /// (including hashing, equality, and ordering) operate on that index. The use
1761 /// of `rustc_index::newtype_index!` means that `Option<Symbol>` only takes up 4 bytes,
1762 /// because `rustc_index::newtype_index!` reserves the last 256 values for tagging purposes.
1764 /// Note that `Symbol` cannot directly be a `rustc_index::newtype_index!` because it
1765 /// implements `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
1766 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
1767 pub struct Symbol(SymbolIndex);
1769 rustc_index::newtype_index! {
1770 struct SymbolIndex { .. }
1774 const fn new(n: u32) -> Self {
1775 Symbol(SymbolIndex::from_u32(n))
1778 /// Maps a string to its interned representation.
1779 pub fn intern(string: &str) -> Self {
1780 with_session_globals(|session_globals| session_globals.symbol_interner.intern(string))
1783 /// Access the underlying string. This is a slowish operation because it
1784 /// requires locking the symbol interner.
1786 /// Note that the lifetime of the return value is a lie. It's not the same
1787 /// as `&self`, but actually tied to the lifetime of the underlying
1788 /// interner. Interners are long-lived, and there are very few of them, and
1789 /// this function is typically used for short-lived things, so in practice
1790 /// it works out ok.
1791 pub fn as_str(&self) -> &str {
1792 with_session_globals(|session_globals| unsafe {
1793 std::mem::transmute::<&str, &str>(session_globals.symbol_interner.get(*self))
1797 pub fn as_u32(self) -> u32 {
1801 pub fn is_empty(self) -> bool {
1805 /// This method is supposed to be used in error messages, so it's expected to be
1806 /// identical to printing the original identifier token written in source code
1807 /// (`token_to_string`, `Ident::to_string`), except that symbols don't keep the rawness flag
1808 /// or edition, so we have to guess the rawness using the global edition.
1809 pub fn to_ident_string(self) -> String {
1810 Ident::with_dummy_span(self).to_string()
1814 impl fmt::Debug for Symbol {
1815 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1816 fmt::Debug::fmt(self.as_str(), f)
1820 impl fmt::Display for Symbol {
1821 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1822 fmt::Display::fmt(self.as_str(), f)
1826 impl<S: Encoder> Encodable<S> for Symbol {
1827 fn encode(&self, s: &mut S) {
1828 s.emit_str(self.as_str());
1832 impl<D: Decoder> Decodable<D> for Symbol {
1834 fn decode(d: &mut D) -> Symbol {
1835 Symbol::intern(&d.read_str())
1839 impl<CTX> HashStable<CTX> for Symbol {
1841 fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
1842 self.as_str().hash_stable(hcx, hasher);
1846 impl<CTX> ToStableHashKey<CTX> for Symbol {
1847 type KeyType = String;
1849 fn to_stable_hash_key(&self, _: &CTX) -> String {
1850 self.as_str().to_string()
1855 pub(crate) struct Interner(Lock<InternerInner>);
1857 // The `&'static str`s in this type actually point into the arena.
1859 // The `FxHashMap`+`Vec` pair could be replaced by `FxIndexSet`, but #75278
1860 // found that to regress performance up to 2% in some cases. This might be
1861 // revisited after further improvements to `indexmap`.
1863 // This type is private to prevent accidentally constructing more than one
1864 // `Interner` on the same thread, which makes it easy to mix up `Symbol`s
1865 // between `Interner`s.
1867 struct InternerInner {
1868 arena: DroplessArena,
1869 names: FxHashMap<&'static str, Symbol>,
1870 strings: Vec<&'static str>,
1874 fn prefill(init: &[&'static str]) -> Self {
1875 Interner(Lock::new(InternerInner {
1876 strings: init.into(),
1877 names: init.iter().copied().zip((0..).map(Symbol::new)).collect(),
1878 ..Default::default()
1883 fn intern(&self, string: &str) -> Symbol {
1884 let mut inner = self.0.lock();
1885 if let Some(&name) = inner.names.get(string) {
1889 let name = Symbol::new(inner.strings.len() as u32);
1891 // SAFETY: we convert from `&str` to `&[u8]`, clone it into the arena,
1892 // and immediately convert the clone back to `&[u8], all because there
1893 // is no `inner.arena.alloc_str()` method. This is clearly safe.
1895 unsafe { str::from_utf8_unchecked(inner.arena.alloc_slice(string.as_bytes())) };
1897 // SAFETY: we can extend the arena allocation to `'static` because we
1898 // only access these while the arena is still alive.
1899 let string: &'static str = unsafe { &*(string as *const str) };
1900 inner.strings.push(string);
1902 // This second hash table lookup can be avoided by using `RawEntryMut`,
1903 // but this code path isn't hot enough for it to be worth it. See
1904 // #91445 for details.
1905 inner.names.insert(string, name);
1909 // Get the symbol as a string. `Symbol::as_str()` should be used in
1910 // preference to this function.
1911 fn get(&self, symbol: Symbol) -> &str {
1912 self.0.lock().strings[symbol.0.as_usize()]
1916 // This module has a very short name because it's used a lot.
1917 /// This module contains all the defined keyword `Symbol`s.
1919 /// Given that `kw` is imported, use them like `kw::keyword_name`.
1920 /// For example `kw::Loop` or `kw::Break`.
1922 pub use super::kw_generated::*;
1925 // This module has a very short name because it's used a lot.
1926 /// This module contains all the defined non-keyword `Symbol`s.
1928 /// Given that `sym` is imported, use them like `sym::symbol_name`.
1929 /// For example `sym::rustfmt` or `sym::u8`.
1932 use std::convert::TryInto;
1935 pub use super::sym_generated::*;
1937 // Used from a macro in `librustc_feature/accepted.rs`
1938 pub use super::kw::MacroRules as macro_rules;
1940 /// Get the symbol for an integer.
1942 /// The first few non-negative integers each have a static symbol and therefore
1944 pub fn integer<N: TryInto<usize> + Copy + ToString>(n: N) -> Symbol {
1945 if let Result::Ok(idx) = n.try_into() {
1947 return Symbol::new(super::SYMBOL_DIGITS_BASE + idx as u32);
1950 Symbol::intern(&n.to_string())
1955 fn is_special(self) -> bool {
1956 self <= kw::Underscore
1959 fn is_used_keyword_always(self) -> bool {
1960 self >= kw::As && self <= kw::While
1963 fn is_used_keyword_conditional(self, edition: impl FnOnce() -> Edition) -> bool {
1964 (self >= kw::Async && self <= kw::Dyn) && edition() >= Edition::Edition2018
1967 fn is_unused_keyword_always(self) -> bool {
1968 self >= kw::Abstract && self <= kw::Yield
1971 fn is_unused_keyword_conditional(self, edition: impl FnOnce() -> Edition) -> bool {
1972 self == kw::Try && edition() >= Edition::Edition2018
1975 pub fn is_reserved(self, edition: impl Copy + FnOnce() -> Edition) -> bool {
1977 || self.is_used_keyword_always()
1978 || self.is_unused_keyword_always()
1979 || self.is_used_keyword_conditional(edition)
1980 || self.is_unused_keyword_conditional(edition)
1983 /// A keyword or reserved identifier that can be used as a path segment.
1984 pub fn is_path_segment_keyword(self) -> bool {
1986 || self == kw::SelfLower
1987 || self == kw::SelfUpper
1988 || self == kw::Crate
1989 || self == kw::PathRoot
1990 || self == kw::DollarCrate
1993 /// Returns `true` if the symbol is `true` or `false`.
1994 pub fn is_bool_lit(self) -> bool {
1995 self == kw::True || self == kw::False
1998 /// Returns `true` if this symbol can be a raw identifier.
1999 pub fn can_be_raw(self) -> bool {
2000 self != kw::Empty && self != kw::Underscore && !self.is_path_segment_keyword()
2005 // Returns `true` for reserved identifiers used internally for elided lifetimes,
2006 // unnamed method parameters, crate root module, error recovery etc.
2007 pub fn is_special(self) -> bool {
2008 self.name.is_special()
2011 /// Returns `true` if the token is a keyword used in the language.
2012 pub fn is_used_keyword(self) -> bool {
2013 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
2014 self.name.is_used_keyword_always()
2015 || self.name.is_used_keyword_conditional(|| self.span.edition())
2018 /// Returns `true` if the token is a keyword reserved for possible future use.
2019 pub fn is_unused_keyword(self) -> bool {
2020 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
2021 self.name.is_unused_keyword_always()
2022 || self.name.is_unused_keyword_conditional(|| self.span.edition())
2025 /// Returns `true` if the token is either a special identifier or a keyword.
2026 pub fn is_reserved(self) -> bool {
2027 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
2028 self.name.is_reserved(|| self.span.edition())
2031 /// A keyword or reserved identifier that can be used as a path segment.
2032 pub fn is_path_segment_keyword(self) -> bool {
2033 self.name.is_path_segment_keyword()
2036 /// We see this identifier in a normal identifier position, like variable name or a type.
2037 /// How was it written originally? Did it use the raw form? Let's try to guess.
2038 pub fn is_raw_guess(self) -> bool {
2039 self.name.can_be_raw() && self.is_reserved()