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
255 ProceduralMasqueradeDummyType,
281 SubdiagnosticMessage,
311 aarch64_target_feature,
312 aarch64_ver_target_feature,
316 abi_c_cmse_nonsecure_call,
318 abi_msp430_interrupt,
332 advanced_slice_patterns,
348 allow_internal_unsafe,
349 allow_internal_unstable,
355 anonymous_lifetime_in_impl_trait,
358 arbitrary_enum_discriminant,
359 arbitrary_self_types,
371 asm_experimental_arch,
379 assert_receiver_is_total_eq,
383 associated_const_equality,
385 associated_type_bounds,
386 associated_type_defaults,
399 augmented_assignments,
401 automatically_derived,
403 avx512_target_feature,
411 bind_by_move_pattern_guards,
423 borrowck_graphviz_format,
424 borrowck_graphviz_postflow,
425 borrowck_graphviz_preflow,
430 braced_empty_structs,
442 capture_disjoint_fields,
459 cfg_target_has_atomic,
460 cfg_target_has_atomic_equal_alignment,
461 cfg_target_has_atomic_load_store,
462 cfg_target_thread_local,
474 closure_lifetime_binder,
475 closure_to_fn_coercion,
476 closure_track_caller,
480 cmpxchg16b_target_feature,
481 cmse_nonsecure_entry,
488 compare_exchange_weak,
498 conservative_impl_trait,
502 const_compare_raw_pointers,
507 const_eval_select_ct,
508 const_evaluatable_checked,
511 const_fn_floating_point_arithmetic,
512 const_fn_fn_ptr_basics,
513 const_fn_trait_bound,
519 const_generic_defaults,
521 const_generics_defaults,
524 const_in_array_repeat_expressions,
531 const_precise_live_drops,
533 const_raw_ptr_to_usize_cast,
536 const_trait_bound_opt_out,
553 core_panic_2015_macro,
564 crate_visibility_modifier,
565 crt_dash_static: "crt-static",
574 custom_inner_attributes,
575 custom_test_frameworks,
582 debug_assert_eq_macro,
584 debug_assert_ne_macro,
587 debug_struct_fields_finish,
590 debug_tuple_fields_finish,
595 default_alloc_error_handler,
596 default_lib_allocator,
597 default_method_body_is_const,
598 default_type_parameter_fallback,
600 delay_span_bug_from_inside_query,
604 deprecated_suggestion,
612 destructuring_assignment,
633 document_private_items,
635 dotdot_in_tuple_patterns,
636 dotdoteq_in_patterns,
644 dropck_parametricity,
655 emit_enum_variant_arg,
667 ermsb_target_feature,
671 exclusive_range_pattern,
672 exhaustive_integer_patterns,
681 explicit_generic_args_with_impl_trait,
684 extended_key_value_attributes,
685 extern_absolute_paths,
686 extern_crate_item_prelude,
710 field_init_shorthand,
717 float_to_int_unchecked,
750 from_size_align_unchecked,
767 generic_associated_types,
768 generic_associated_types_extended,
776 half_open_range_patterns,
778 hexagon_target_feature,
780 homogeneous_aggregate,
797 if_while_or_patterns,
799 impl_header_lifetime_elision,
802 impl_trait_in_bindings,
814 inclusive_range_syntax,
817 infer_outlives_requirements,
818 infer_static_outlives_requirements,
819 inherent_associated_types,
833 irrefutable_let_patterns,
837 issue_5723_bootstrap,
838 issue_tracker_base_url,
853 lazy_normalization_consts,
868 link_llvm_intrinsics,
889 macro_at_most_once_rep,
890 macro_attributes_in_derive_output,
893 macro_lifetime_matcher,
894 macro_literal_matcher,
907 match_beginning_vert,
908 match_default_bindings,
938 min_type_alias_impl_trait,
949 more_qualified_paths,
951 movbe_target_feature,
963 native_link_modifiers,
964 native_link_modifiers_as_needed,
965 native_link_modifiers_bundle,
966 native_link_modifiers_verbatim,
967 native_link_modifiers_whole_archive,
1005 non_exhaustive_omitted_patterns_lint,
1017 object_safe_for_dispatch,
1020 omit_gdb_pretty_printer_section,
1029 optin_builtin_traits,
1038 overlapping_marker_traits,
1050 panic_implementation,
1065 pattern_parentheses,
1068 platform_intrinsics,
1077 post_dash_lto: "post-lto",
1078 powerpc_target_feature,
1083 pre_dash_lto: "pre-lto",
1084 precise_pointer_size_matching,
1088 prefetch_read_instruction,
1089 prefetch_write_data,
1090 prefetch_write_instruction,
1098 proc_dash_macro: "proc-macro",
1100 proc_macro_attribute,
1101 proc_macro_def_site,
1106 proc_macro_internals,
1108 proc_macro_non_items,
1109 proc_macro_path_invoc,
1118 ptr_offset_from_unsigned,
1126 quad_precision_float,
1129 range_inclusive_new,
1134 re_rebalance_coherence,
1137 read_enum_variant_arg,
1145 reexport_test_harness_main,
1146 ref_unwind_safe_trait,
1163 relaxed_struct_unsize,
1178 riscv_target_feature,
1197 rust_eh_catch_typeinfo,
1198 rust_eh_personality,
1199 rust_eh_register_frames,
1200 rust_eh_unregister_frames,
1204 rustc_allocator_nounwind,
1205 rustc_allow_const_fn_unstable,
1206 rustc_allow_incoherent_impl,
1207 rustc_allowed_through_unstable_modules,
1210 rustc_builtin_macro,
1211 rustc_capture_analysis,
1213 rustc_coherence_is_core,
1215 rustc_const_unstable,
1216 rustc_conversion_suggestion,
1218 rustc_diagnostic_item,
1219 rustc_diagnostic_macros,
1221 rustc_do_not_const_check,
1223 rustc_dump_env_program_clauses,
1224 rustc_dump_program_clauses,
1225 rustc_dump_user_substs,
1228 rustc_evaluate_where_clauses,
1229 rustc_expected_cgu_reuse,
1230 rustc_has_incoherent_inherent_impls,
1231 rustc_if_this_changed,
1232 rustc_inherit_overflow_checks,
1233 rustc_insignificant_dtor,
1235 rustc_layout_scalar_valid_range_end,
1236 rustc_layout_scalar_valid_range_start,
1237 rustc_legacy_const_generics,
1238 rustc_lint_diagnostics,
1239 rustc_lint_query_instability,
1240 rustc_macro_transparency,
1243 rustc_must_implement_one_of,
1244 rustc_nonnull_optimization_guaranteed,
1245 rustc_object_lifetime_default,
1246 rustc_on_unimplemented,
1249 rustc_partition_codegened,
1250 rustc_partition_reused,
1251 rustc_pass_by_value,
1253 rustc_peek_definite_init,
1254 rustc_peek_liveness,
1255 rustc_peek_maybe_init,
1256 rustc_peek_maybe_uninit,
1257 rustc_polymorphize_error,
1259 rustc_proc_macro_decls,
1262 rustc_reservation_impl,
1264 rustc_skip_array_during_method_dispatch,
1265 rustc_specialization_trait,
1267 rustc_std_internal_symbol,
1268 rustc_strict_coherence,
1271 rustc_then_this_would_need,
1272 rustc_trivial_field_reads,
1273 rustc_unsafe_specialization_marker,
1278 rvalue_static_promotion,
1329 simd_reduce_add_ordered,
1330 simd_reduce_add_unordered,
1335 simd_reduce_max_nanless,
1337 simd_reduce_min_nanless,
1338 simd_reduce_mul_ordered,
1339 simd_reduce_mul_unordered,
1344 simd_saturating_add,
1345 simd_saturating_sub,
1348 simd_select_bitmask,
1376 sse4a_target_feature,
1388 std_panic_2015_macro,
1391 stmt_expr_attributes,
1392 stop_after_dataflow,
1395 str_split_whitespace,
1402 struct_field_attributes,
1425 target_has_atomic_equal_alignment,
1426 target_has_atomic_load_store,
1428 target_pointer_width,
1429 target_target_vendor,
1430 target_thread_local,
1436 termination_trait_test,
1439 test_accepted_feature,
1441 test_removed_feature,
1449 thumb_mode: "thumb-mode",
1478 type_alias_enum_variants,
1479 type_alias_impl_trait,
1481 type_changing_struct_update,
1491 unaligned_volatile_load,
1492 unaligned_volatile_store,
1501 underscore_const_names,
1503 underscore_lifetimes,
1505 unimplemented_macro,
1507 universal_impl_trait,
1514 unreachable_2015_macro,
1516 unreachable_2021_macro,
1518 unreachable_display,
1520 unrestricted_attribute_tokens,
1521 unsafe_block_in_unsafe_fn,
1523 unsafe_no_drop_flag,
1524 unsafe_pin_internals,
1528 unsized_tuple_coercion,
1532 unused_qualifications,
1559 visible_private_types,
1561 volatile_copy_memory,
1562 volatile_copy_nonoverlapping_memory,
1564 volatile_set_memory,
1571 wasm_target_feature,
1576 with_negative_coherence,
1588 yeet_desugar_details,
1595 #[derive(Copy, Clone, Eq, HashStable_Generic, Encodable, Decodable)]
1603 /// Constructs a new identifier from a symbol and a span.
1604 pub const fn new(name: Symbol, span: Span) -> Ident {
1605 Ident { name, span }
1608 /// Constructs a new identifier with a dummy span.
1610 pub const fn with_dummy_span(name: Symbol) -> Ident {
1611 Ident::new(name, DUMMY_SP)
1615 pub fn empty() -> Ident {
1616 Ident::with_dummy_span(kw::Empty)
1619 /// Maps a string to an identifier with a dummy span.
1620 pub fn from_str(string: &str) -> Ident {
1621 Ident::with_dummy_span(Symbol::intern(string))
1624 /// Maps a string and a span to an identifier.
1625 pub fn from_str_and_span(string: &str, span: Span) -> Ident {
1626 Ident::new(Symbol::intern(string), span)
1629 /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
1630 pub fn with_span_pos(self, span: Span) -> Ident {
1631 Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
1634 pub fn without_first_quote(self) -> Ident {
1635 Ident::new(Symbol::intern(self.as_str().trim_start_matches('\'')), self.span)
1638 /// "Normalize" ident for use in comparisons using "item hygiene".
1639 /// Identifiers with same string value become same if they came from the same macro 2.0 macro
1640 /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
1641 /// different macro 2.0 macros.
1642 /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
1643 pub fn normalize_to_macros_2_0(self) -> Ident {
1644 Ident::new(self.name, self.span.normalize_to_macros_2_0())
1647 /// "Normalize" ident for use in comparisons using "local variable hygiene".
1648 /// Identifiers with same string value become same if they came from the same non-transparent
1649 /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
1650 /// non-transparent macros.
1651 /// Technically, this operation strips all transparent marks from ident's syntactic context.
1652 pub fn normalize_to_macro_rules(self) -> Ident {
1653 Ident::new(self.name, self.span.normalize_to_macro_rules())
1656 /// Access the underlying string. This is a slowish operation because it
1657 /// requires locking the symbol interner.
1659 /// Note that the lifetime of the return value is a lie. See
1660 /// `Symbol::as_str()` for details.
1661 pub fn as_str(&self) -> &str {
1666 impl PartialEq for Ident {
1667 fn eq(&self, rhs: &Self) -> bool {
1668 self.name == rhs.name && self.span.eq_ctxt(rhs.span)
1672 impl Hash for Ident {
1673 fn hash<H: Hasher>(&self, state: &mut H) {
1674 self.name.hash(state);
1675 self.span.ctxt().hash(state);
1679 impl fmt::Debug for Ident {
1680 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1681 fmt::Display::fmt(self, f)?;
1682 fmt::Debug::fmt(&self.span.ctxt(), f)
1686 /// This implementation is supposed to be used in error messages, so it's expected to be identical
1687 /// to printing the original identifier token written in source code (`token_to_string`),
1688 /// except that AST identifiers don't keep the rawness flag, so we have to guess it.
1689 impl fmt::Display for Ident {
1690 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1691 fmt::Display::fmt(&IdentPrinter::new(self.name, self.is_raw_guess(), None), f)
1695 /// This is the most general way to print identifiers.
1696 /// AST pretty-printer is used as a fallback for turning AST structures into token streams for
1697 /// proc macros. Additionally, proc macros may stringify their input and expect it survive the
1698 /// stringification (especially true for proc macro derives written between Rust 1.15 and 1.30).
1699 /// So we need to somehow pretty-print `$crate` in a way preserving at least some of its
1700 /// hygiene data, most importantly name of the crate it refers to.
1701 /// As a result we print `$crate` as `crate` if it refers to the local crate
1702 /// and as `::other_crate_name` if it refers to some other crate.
1703 /// Note, that this is only done if the ident token is printed from inside of AST pretty-printing,
1704 /// but not otherwise. Pretty-printing is the only way for proc macros to discover token contents,
1705 /// so we should not perform this lossy conversion if the top level call to the pretty-printer was
1706 /// done for a token stream or a single token.
1707 pub struct IdentPrinter {
1710 /// Span used for retrieving the crate name to which `$crate` refers to,
1711 /// if this field is `None` then the `$crate` conversion doesn't happen.
1712 convert_dollar_crate: Option<Span>,
1716 /// The most general `IdentPrinter` constructor. Do not use this.
1717 pub fn new(symbol: Symbol, is_raw: bool, convert_dollar_crate: Option<Span>) -> IdentPrinter {
1718 IdentPrinter { symbol, is_raw, convert_dollar_crate }
1721 /// This implementation is supposed to be used when printing identifiers
1722 /// as a part of pretty-printing for larger AST pieces.
1723 /// Do not use this either.
1724 pub fn for_ast_ident(ident: Ident, is_raw: bool) -> IdentPrinter {
1725 IdentPrinter::new(ident.name, is_raw, Some(ident.span))
1729 impl fmt::Display for IdentPrinter {
1730 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1733 } else if self.symbol == kw::DollarCrate {
1734 if let Some(span) = self.convert_dollar_crate {
1735 let converted = span.ctxt().dollar_crate_name();
1736 if !converted.is_path_segment_keyword() {
1739 return fmt::Display::fmt(&converted, f);
1742 fmt::Display::fmt(&self.symbol, f)
1746 /// An newtype around `Ident` that calls [Ident::normalize_to_macro_rules] on
1748 // FIXME(matthewj, petrochenkov) Use this more often, add a similar
1749 // `ModernIdent` struct and use that as well.
1750 #[derive(Copy, Clone, Eq, PartialEq, Hash)]
1751 pub struct MacroRulesNormalizedIdent(Ident);
1753 impl MacroRulesNormalizedIdent {
1754 pub fn new(ident: Ident) -> Self {
1755 Self(ident.normalize_to_macro_rules())
1759 impl fmt::Debug for MacroRulesNormalizedIdent {
1760 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1761 fmt::Debug::fmt(&self.0, f)
1765 impl fmt::Display for MacroRulesNormalizedIdent {
1766 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1767 fmt::Display::fmt(&self.0, f)
1771 /// An interned string.
1773 /// Internally, a `Symbol` is implemented as an index, and all operations
1774 /// (including hashing, equality, and ordering) operate on that index. The use
1775 /// of `rustc_index::newtype_index!` means that `Option<Symbol>` only takes up 4 bytes,
1776 /// because `rustc_index::newtype_index!` reserves the last 256 values for tagging purposes.
1778 /// Note that `Symbol` cannot directly be a `rustc_index::newtype_index!` because it
1779 /// implements `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
1780 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
1781 pub struct Symbol(SymbolIndex);
1783 rustc_index::newtype_index! {
1784 struct SymbolIndex { .. }
1788 const fn new(n: u32) -> Self {
1789 Symbol(SymbolIndex::from_u32(n))
1792 /// Maps a string to its interned representation.
1793 pub fn intern(string: &str) -> Self {
1794 with_session_globals(|session_globals| session_globals.symbol_interner.intern(string))
1797 /// Access the underlying string. This is a slowish operation because it
1798 /// requires locking the symbol interner.
1800 /// Note that the lifetime of the return value is a lie. It's not the same
1801 /// as `&self`, but actually tied to the lifetime of the underlying
1802 /// interner. Interners are long-lived, and there are very few of them, and
1803 /// this function is typically used for short-lived things, so in practice
1804 /// it works out ok.
1805 pub fn as_str(&self) -> &str {
1806 with_session_globals(|session_globals| unsafe {
1807 std::mem::transmute::<&str, &str>(session_globals.symbol_interner.get(*self))
1811 pub fn as_u32(self) -> u32 {
1815 pub fn is_empty(self) -> bool {
1819 /// This method is supposed to be used in error messages, so it's expected to be
1820 /// identical to printing the original identifier token written in source code
1821 /// (`token_to_string`, `Ident::to_string`), except that symbols don't keep the rawness flag
1822 /// or edition, so we have to guess the rawness using the global edition.
1823 pub fn to_ident_string(self) -> String {
1824 Ident::with_dummy_span(self).to_string()
1828 impl fmt::Debug for Symbol {
1829 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1830 fmt::Debug::fmt(self.as_str(), f)
1834 impl fmt::Display for Symbol {
1835 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1836 fmt::Display::fmt(self.as_str(), f)
1840 impl<S: Encoder> Encodable<S> for Symbol {
1841 fn encode(&self, s: &mut S) {
1842 s.emit_str(self.as_str());
1846 impl<D: Decoder> Decodable<D> for Symbol {
1848 fn decode(d: &mut D) -> Symbol {
1849 Symbol::intern(&d.read_str())
1853 impl<CTX> HashStable<CTX> for Symbol {
1855 fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
1856 self.as_str().hash_stable(hcx, hasher);
1860 impl<CTX> ToStableHashKey<CTX> for Symbol {
1861 type KeyType = String;
1863 fn to_stable_hash_key(&self, _: &CTX) -> String {
1864 self.as_str().to_string()
1869 pub(crate) struct Interner(Lock<InternerInner>);
1871 // The `&'static str`s in this type actually point into the arena.
1873 // The `FxHashMap`+`Vec` pair could be replaced by `FxIndexSet`, but #75278
1874 // found that to regress performance up to 2% in some cases. This might be
1875 // revisited after further improvements to `indexmap`.
1877 // This type is private to prevent accidentally constructing more than one
1878 // `Interner` on the same thread, which makes it easy to mix up `Symbol`s
1879 // between `Interner`s.
1881 struct InternerInner {
1882 arena: DroplessArena,
1883 names: FxHashMap<&'static str, Symbol>,
1884 strings: Vec<&'static str>,
1888 fn prefill(init: &[&'static str]) -> Self {
1889 Interner(Lock::new(InternerInner {
1890 strings: init.into(),
1891 names: init.iter().copied().zip((0..).map(Symbol::new)).collect(),
1892 ..Default::default()
1897 fn intern(&self, string: &str) -> Symbol {
1898 let mut inner = self.0.lock();
1899 if let Some(&name) = inner.names.get(string) {
1903 let name = Symbol::new(inner.strings.len() as u32);
1905 // SAFETY: we convert from `&str` to `&[u8]`, clone it into the arena,
1906 // and immediately convert the clone back to `&[u8], all because there
1907 // is no `inner.arena.alloc_str()` method. This is clearly safe.
1909 unsafe { str::from_utf8_unchecked(inner.arena.alloc_slice(string.as_bytes())) };
1911 // SAFETY: we can extend the arena allocation to `'static` because we
1912 // only access these while the arena is still alive.
1913 let string: &'static str = unsafe { &*(string as *const str) };
1914 inner.strings.push(string);
1916 // This second hash table lookup can be avoided by using `RawEntryMut`,
1917 // but this code path isn't hot enough for it to be worth it. See
1918 // #91445 for details.
1919 inner.names.insert(string, name);
1923 // Get the symbol as a string. `Symbol::as_str()` should be used in
1924 // preference to this function.
1925 fn get(&self, symbol: Symbol) -> &str {
1926 self.0.lock().strings[symbol.0.as_usize()]
1930 // This module has a very short name because it's used a lot.
1931 /// This module contains all the defined keyword `Symbol`s.
1933 /// Given that `kw` is imported, use them like `kw::keyword_name`.
1934 /// For example `kw::Loop` or `kw::Break`.
1936 pub use super::kw_generated::*;
1939 // This module has a very short name because it's used a lot.
1940 /// This module contains all the defined non-keyword `Symbol`s.
1942 /// Given that `sym` is imported, use them like `sym::symbol_name`.
1943 /// For example `sym::rustfmt` or `sym::u8`.
1946 use std::convert::TryInto;
1949 pub use super::sym_generated::*;
1951 // Used from a macro in `librustc_feature/accepted.rs`
1952 pub use super::kw::MacroRules as macro_rules;
1954 /// Get the symbol for an integer.
1956 /// The first few non-negative integers each have a static symbol and therefore
1958 pub fn integer<N: TryInto<usize> + Copy + ToString>(n: N) -> Symbol {
1959 if let Result::Ok(idx) = n.try_into() {
1961 return Symbol::new(super::SYMBOL_DIGITS_BASE + idx as u32);
1964 Symbol::intern(&n.to_string())
1969 fn is_special(self) -> bool {
1970 self <= kw::Underscore
1973 fn is_used_keyword_always(self) -> bool {
1974 self >= kw::As && self <= kw::While
1977 fn is_used_keyword_conditional(self, edition: impl FnOnce() -> Edition) -> bool {
1978 (self >= kw::Async && self <= kw::Dyn) && edition() >= Edition::Edition2018
1981 fn is_unused_keyword_always(self) -> bool {
1982 self >= kw::Abstract && self <= kw::Yield
1985 fn is_unused_keyword_conditional(self, edition: impl FnOnce() -> Edition) -> bool {
1986 self == kw::Try && edition() >= Edition::Edition2018
1989 pub fn is_reserved(self, edition: impl Copy + FnOnce() -> Edition) -> bool {
1991 || self.is_used_keyword_always()
1992 || self.is_unused_keyword_always()
1993 || self.is_used_keyword_conditional(edition)
1994 || self.is_unused_keyword_conditional(edition)
1997 /// A keyword or reserved identifier that can be used as a path segment.
1998 pub fn is_path_segment_keyword(self) -> bool {
2000 || self == kw::SelfLower
2001 || self == kw::SelfUpper
2002 || self == kw::Crate
2003 || self == kw::PathRoot
2004 || self == kw::DollarCrate
2007 /// Returns `true` if the symbol is `true` or `false`.
2008 pub fn is_bool_lit(self) -> bool {
2009 self == kw::True || self == kw::False
2012 /// Returns `true` if this symbol can be a raw identifier.
2013 pub fn can_be_raw(self) -> bool {
2014 self != kw::Empty && self != kw::Underscore && !self.is_path_segment_keyword()
2019 // Returns `true` for reserved identifiers used internally for elided lifetimes,
2020 // unnamed method parameters, crate root module, error recovery etc.
2021 pub fn is_special(self) -> bool {
2022 self.name.is_special()
2025 /// Returns `true` if the token is a keyword used in the language.
2026 pub fn is_used_keyword(self) -> bool {
2027 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
2028 self.name.is_used_keyword_always()
2029 || self.name.is_used_keyword_conditional(|| self.span.edition())
2032 /// Returns `true` if the token is a keyword reserved for possible future use.
2033 pub fn is_unused_keyword(self) -> bool {
2034 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
2035 self.name.is_unused_keyword_always()
2036 || self.name.is_unused_keyword_conditional(|| self.span.edition())
2039 /// Returns `true` if the token is either a special identifier or a keyword.
2040 pub fn is_reserved(self) -> bool {
2041 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
2042 self.name.is_reserved(|| self.span.edition())
2045 /// A keyword or reserved identifier that can be used as a path segment.
2046 pub fn is_path_segment_keyword(self) -> bool {
2047 self.name.is_path_segment_keyword()
2050 /// We see this identifier in a normal identifier position, like variable name or a type.
2051 /// How was it written originally? Did it use the raw form? Let's try to guess.
2052 pub fn is_raw_guess(self) -> bool {
2053 self.name.can_be_raw() && self.is_reserved()