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",
106 // Pre-interned symbols that can be referred to with `rustc_span::sym::*`.
108 // The symbol is the stringified identifier unless otherwise specified, in
109 // which case the name should mention the non-identifier punctuation.
110 // E.g. `sym::proc_dash_macro` represents "proc-macro", and it shouldn't be
111 // called `sym::proc_macro` because then it's easy to mistakenly think it
112 // represents "proc_macro".
114 // As well as the symbols listed, there are symbols for the strings
115 // "0", "1", ..., "9", which are accessible via `sym::integer`.
117 // The proc macro will abort if symbols are not in alphabetical order (as
118 // defined by `impl Ord for str`) or if any symbols are duplicated. Vim
119 // users can sort the list by selecting it and executing the command
120 // `:'<,'>!LC_ALL=C sort`.
122 // There is currently no checking that all symbols are used; that would be
231 ProceduralMasqueradeDummyType,
279 aarch64_target_feature,
283 abi_c_cmse_nonsecure_call,
285 abi_msp430_interrupt,
299 advanced_slice_patterns,
315 allow_internal_unsafe,
316 allow_internal_unstable,
324 arbitrary_enum_discriminant,
325 arbitrary_self_types,
337 asm_experimental_arch,
345 assert_receiver_is_total_eq,
348 associated_const_equality,
350 associated_type_bounds,
351 associated_type_defaults,
364 augmented_assignments,
366 automatically_derived,
368 avx512_target_feature,
376 bind_by_move_pattern_guards,
388 borrowck_graphviz_format,
389 borrowck_graphviz_postflow,
390 borrowck_graphviz_preflow,
395 braced_empty_structs,
407 capture_disjoint_fields,
423 cfg_target_has_atomic,
424 cfg_target_thread_local,
436 closure_to_fn_coercion,
437 closure_track_caller,
441 cmpxchg16b_target_feature,
442 cmse_nonsecure_entry,
449 compare_exchange_weak,
458 conservative_impl_trait,
462 const_compare_raw_pointers,
467 const_eval_select_ct,
468 const_evaluatable_checked,
471 const_fn_floating_point_arithmetic,
472 const_fn_fn_ptr_basics,
473 const_fn_trait_bound,
479 const_generic_defaults,
481 const_generics_defaults,
484 const_in_array_repeat_expressions,
491 const_precise_live_drops,
494 const_raw_ptr_to_usize_cast,
497 const_trait_bound_opt_out,
514 core_panic_2015_macro,
525 crate_visibility_modifier,
526 crt_dash_static: "crt-static",
535 custom_inner_attributes,
536 custom_test_frameworks,
542 debug_assert_eq_macro,
544 debug_assert_ne_macro,
552 default_alloc_error_handler,
553 default_lib_allocator,
554 default_method_body_is_const,
555 default_type_parameter_fallback,
557 delay_span_bug_from_inside_query,
566 destructuring_assignment,
587 document_private_items,
589 dotdot_in_tuple_patterns,
590 dotdoteq_in_patterns,
598 dropck_parametricity,
609 emit_enum_variant_arg,
621 ermsb_target_feature,
625 exclusive_range_pattern,
626 exhaustive_integer_patterns,
635 explicit_generic_args_with_impl_trait,
638 extended_key_value_attributes,
639 extern_absolute_paths,
640 extern_crate_item_prelude,
665 field_init_shorthand,
671 float_to_int_unchecked,
704 from_size_align_unchecked,
718 generic_associated_types,
726 half_open_range_patterns,
728 hexagon_target_feature,
730 homogeneous_aggregate,
747 if_while_or_patterns,
749 impl_header_lifetime_elision,
752 impl_trait_in_bindings,
762 inclusive_range_syntax,
765 infer_outlives_requirements,
766 infer_static_outlives_requirements,
767 inherent_associated_types,
779 irrefutable_let_patterns,
783 issue_5723_bootstrap,
784 issue_tracker_base_url,
798 lazy_normalization_consts,
813 link_llvm_intrinsics,
833 macro_at_most_once_rep,
834 macro_attributes_in_derive_output,
837 macro_lifetime_matcher,
838 macro_literal_matcher,
850 match_beginning_vert,
851 match_default_bindings,
880 min_type_alias_impl_trait,
890 more_qualified_paths,
892 movbe_target_feature,
905 native_link_modifiers,
906 native_link_modifiers_as_needed,
907 native_link_modifiers_bundle,
908 native_link_modifiers_verbatim,
909 native_link_modifiers_whole_archive,
947 non_exhaustive_omitted_patterns_lint,
959 object_safe_for_dispatch,
962 omit_gdb_pretty_printer_section,
971 optin_builtin_traits,
980 overlapping_marker_traits,
992 panic_implementation,
1007 pattern_parentheses,
1011 platform_intrinsics,
1020 post_dash_lto: "post-lto",
1021 powerpc_target_feature,
1026 pre_dash_lto: "pre-lto",
1027 precise_pointer_size_matching,
1031 prefetch_read_instruction,
1032 prefetch_write_data,
1033 prefetch_write_instruction,
1041 proc_dash_macro: "proc-macro",
1043 proc_macro_attribute,
1044 proc_macro_def_site,
1049 proc_macro_internals,
1051 proc_macro_non_items,
1052 proc_macro_path_invoc,
1067 quad_precision_float,
1070 range_inclusive_new,
1075 re_rebalance_coherence,
1078 read_enum_variant_arg,
1086 reexport_test_harness_main,
1087 ref_unwind_safe_trait,
1104 relaxed_struct_unsize,
1115 reserved_r9: "reserved-r9",
1121 riscv_target_feature,
1137 rust_eh_catch_typeinfo,
1138 rust_eh_personality,
1139 rust_eh_register_frames,
1140 rust_eh_unregister_frames,
1144 rustc_allocator_nounwind,
1145 rustc_allow_const_fn_unstable,
1147 rustc_builtin_macro,
1148 rustc_capture_analysis,
1151 rustc_const_unstable,
1152 rustc_conversion_suggestion,
1155 rustc_diagnostic_item,
1156 rustc_diagnostic_macros,
1158 rustc_do_not_const_check,
1160 rustc_dump_env_program_clauses,
1161 rustc_dump_program_clauses,
1162 rustc_dump_user_substs,
1165 rustc_evaluate_where_clauses,
1166 rustc_expected_cgu_reuse,
1167 rustc_if_this_changed,
1168 rustc_inherit_overflow_checks,
1169 rustc_insignificant_dtor,
1171 rustc_layout_scalar_valid_range_end,
1172 rustc_layout_scalar_valid_range_start,
1173 rustc_legacy_const_generics,
1174 rustc_macro_transparency,
1177 rustc_must_implement_one_of,
1178 rustc_nonnull_optimization_guaranteed,
1179 rustc_object_lifetime_default,
1180 rustc_on_unimplemented,
1183 rustc_partition_codegened,
1184 rustc_partition_reused,
1185 rustc_pass_by_value,
1187 rustc_peek_definite_init,
1188 rustc_peek_liveness,
1189 rustc_peek_maybe_init,
1190 rustc_peek_maybe_uninit,
1191 rustc_polymorphize_error,
1193 rustc_proc_macro_decls,
1196 rustc_reservation_impl,
1198 rustc_skip_array_during_method_dispatch,
1199 rustc_specialization_trait,
1201 rustc_std_internal_symbol,
1202 rustc_strict_coherence,
1205 rustc_then_this_would_need,
1206 rustc_trivial_field_reads,
1207 rustc_unsafe_specialization_marker,
1209 rustc_with_negative_coherence,
1213 rvalue_static_promotion,
1263 simd_reduce_add_ordered,
1264 simd_reduce_add_unordered,
1269 simd_reduce_max_nanless,
1271 simd_reduce_min_nanless,
1272 simd_reduce_mul_ordered,
1273 simd_reduce_mul_unordered,
1278 simd_saturating_add,
1279 simd_saturating_sub,
1282 simd_select_bitmask,
1313 sse4a_target_feature,
1325 std_panic_2015_macro,
1328 stmt_expr_attributes,
1329 stop_after_dataflow,
1335 struct_field_attributes,
1357 target_has_atomic_equal_alignment,
1358 target_has_atomic_load_store,
1360 target_pointer_width,
1361 target_target_vendor,
1362 target_thread_local,
1368 termination_trait_test,
1371 test_accepted_feature,
1373 test_removed_feature,
1380 thumb_mode: "thumb-mode",
1405 type_alias_enum_variants,
1406 type_alias_impl_trait,
1408 type_changing_struct_update,
1418 unaligned_volatile_load,
1419 unaligned_volatile_store,
1428 underscore_const_names,
1430 underscore_lifetimes,
1432 unimplemented_macro,
1434 universal_impl_trait,
1442 unrestricted_attribute_tokens,
1443 unsafe_block_in_unsafe_fn,
1445 unsafe_no_drop_flag,
1449 unsized_tuple_coercion,
1452 unused_qualifications,
1476 visible_private_types,
1478 volatile_copy_memory,
1479 volatile_copy_nonoverlapping_memory,
1481 volatile_set_memory,
1488 wasm_target_feature,
1509 #[derive(Copy, Clone, Eq, HashStable_Generic, Encodable, Decodable)]
1517 /// Constructs a new identifier from a symbol and a span.
1518 pub const fn new(name: Symbol, span: Span) -> Ident {
1519 Ident { name, span }
1522 /// Constructs a new identifier with a dummy span.
1524 pub const fn with_dummy_span(name: Symbol) -> Ident {
1525 Ident::new(name, DUMMY_SP)
1529 pub fn empty() -> Ident {
1530 Ident::with_dummy_span(kw::Empty)
1533 /// Maps a string to an identifier with a dummy span.
1534 pub fn from_str(string: &str) -> Ident {
1535 Ident::with_dummy_span(Symbol::intern(string))
1538 /// Maps a string and a span to an identifier.
1539 pub fn from_str_and_span(string: &str, span: Span) -> Ident {
1540 Ident::new(Symbol::intern(string), span)
1543 /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
1544 pub fn with_span_pos(self, span: Span) -> Ident {
1545 Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
1548 pub fn without_first_quote(self) -> Ident {
1549 Ident::new(Symbol::intern(self.as_str().trim_start_matches('\'')), self.span)
1552 /// "Normalize" ident for use in comparisons using "item hygiene".
1553 /// Identifiers with same string value become same if they came from the same macro 2.0 macro
1554 /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
1555 /// different macro 2.0 macros.
1556 /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
1557 pub fn normalize_to_macros_2_0(self) -> Ident {
1558 Ident::new(self.name, self.span.normalize_to_macros_2_0())
1561 /// "Normalize" ident for use in comparisons using "local variable hygiene".
1562 /// Identifiers with same string value become same if they came from the same non-transparent
1563 /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
1564 /// non-transparent macros.
1565 /// Technically, this operation strips all transparent marks from ident's syntactic context.
1566 pub fn normalize_to_macro_rules(self) -> Ident {
1567 Ident::new(self.name, self.span.normalize_to_macro_rules())
1570 /// Access the underlying string. This is a slowish operation because it
1571 /// requires locking the symbol interner.
1573 /// Note that the lifetime of the return value is a lie. See
1574 /// `Symbol::as_str()` for details.
1575 pub fn as_str(&self) -> &str {
1580 impl PartialEq for Ident {
1581 fn eq(&self, rhs: &Self) -> bool {
1582 self.name == rhs.name && self.span.ctxt() == rhs.span.ctxt()
1586 impl Hash for Ident {
1587 fn hash<H: Hasher>(&self, state: &mut H) {
1588 self.name.hash(state);
1589 self.span.ctxt().hash(state);
1593 impl fmt::Debug for Ident {
1594 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1595 fmt::Display::fmt(self, f)?;
1596 fmt::Debug::fmt(&self.span.ctxt(), f)
1600 /// This implementation is supposed to be used in error messages, so it's expected to be identical
1601 /// to printing the original identifier token written in source code (`token_to_string`),
1602 /// except that AST identifiers don't keep the rawness flag, so we have to guess it.
1603 impl fmt::Display for Ident {
1604 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1605 fmt::Display::fmt(&IdentPrinter::new(self.name, self.is_raw_guess(), None), f)
1609 /// This is the most general way to print identifiers.
1610 /// AST pretty-printer is used as a fallback for turning AST structures into token streams for
1611 /// proc macros. Additionally, proc macros may stringify their input and expect it survive the
1612 /// stringification (especially true for proc macro derives written between Rust 1.15 and 1.30).
1613 /// So we need to somehow pretty-print `$crate` in a way preserving at least some of its
1614 /// hygiene data, most importantly name of the crate it refers to.
1615 /// As a result we print `$crate` as `crate` if it refers to the local crate
1616 /// and as `::other_crate_name` if it refers to some other crate.
1617 /// Note, that this is only done if the ident token is printed from inside of AST pretty-pringing,
1618 /// but not otherwise. Pretty-printing is the only way for proc macros to discover token contents,
1619 /// so we should not perform this lossy conversion if the top level call to the pretty-printer was
1620 /// done for a token stream or a single token.
1621 pub struct IdentPrinter {
1624 /// Span used for retrieving the crate name to which `$crate` refers to,
1625 /// if this field is `None` then the `$crate` conversion doesn't happen.
1626 convert_dollar_crate: Option<Span>,
1630 /// The most general `IdentPrinter` constructor. Do not use this.
1631 pub fn new(symbol: Symbol, is_raw: bool, convert_dollar_crate: Option<Span>) -> IdentPrinter {
1632 IdentPrinter { symbol, is_raw, convert_dollar_crate }
1635 /// This implementation is supposed to be used when printing identifiers
1636 /// as a part of pretty-printing for larger AST pieces.
1637 /// Do not use this either.
1638 pub fn for_ast_ident(ident: Ident, is_raw: bool) -> IdentPrinter {
1639 IdentPrinter::new(ident.name, is_raw, Some(ident.span))
1643 impl fmt::Display for IdentPrinter {
1644 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1647 } else if self.symbol == kw::DollarCrate {
1648 if let Some(span) = self.convert_dollar_crate {
1649 let converted = span.ctxt().dollar_crate_name();
1650 if !converted.is_path_segment_keyword() {
1653 return fmt::Display::fmt(&converted, f);
1656 fmt::Display::fmt(&self.symbol, f)
1660 /// An newtype around `Ident` that calls [Ident::normalize_to_macro_rules] on
1662 // FIXME(matthewj, petrochenkov) Use this more often, add a similar
1663 // `ModernIdent` struct and use that as well.
1664 #[derive(Copy, Clone, Eq, PartialEq, Hash)]
1665 pub struct MacroRulesNormalizedIdent(Ident);
1667 impl MacroRulesNormalizedIdent {
1668 pub fn new(ident: Ident) -> Self {
1669 Self(ident.normalize_to_macro_rules())
1673 impl fmt::Debug for MacroRulesNormalizedIdent {
1674 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1675 fmt::Debug::fmt(&self.0, f)
1679 impl fmt::Display for MacroRulesNormalizedIdent {
1680 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1681 fmt::Display::fmt(&self.0, f)
1685 /// An interned string.
1687 /// Internally, a `Symbol` is implemented as an index, and all operations
1688 /// (including hashing, equality, and ordering) operate on that index. The use
1689 /// of `rustc_index::newtype_index!` means that `Option<Symbol>` only takes up 4 bytes,
1690 /// because `rustc_index::newtype_index!` reserves the last 256 values for tagging purposes.
1692 /// Note that `Symbol` cannot directly be a `rustc_index::newtype_index!` because it
1693 /// implements `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
1694 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
1695 pub struct Symbol(SymbolIndex);
1697 rustc_index::newtype_index! {
1698 struct SymbolIndex { .. }
1702 const fn new(n: u32) -> Self {
1703 Symbol(SymbolIndex::from_u32(n))
1706 /// Maps a string to its interned representation.
1707 pub fn intern(string: &str) -> Self {
1708 with_session_globals(|session_globals| session_globals.symbol_interner.intern(string))
1711 /// Access the underlying string. This is a slowish operation because it
1712 /// requires locking the symbol interner.
1714 /// Note that the lifetime of the return value is a lie. It's not the same
1715 /// as `&self`, but actually tied to the lifetime of the underlying
1716 /// interner. Interners are long-lived, and there are very few of them, and
1717 /// this function is typically used for short-lived things, so in practice
1718 /// it works out ok.
1719 pub fn as_str(&self) -> &str {
1720 with_session_globals(|session_globals| unsafe {
1721 std::mem::transmute::<&str, &str>(session_globals.symbol_interner.get(*self))
1725 pub fn as_u32(self) -> u32 {
1729 pub fn is_empty(self) -> bool {
1733 /// This method is supposed to be used in error messages, so it's expected to be
1734 /// identical to printing the original identifier token written in source code
1735 /// (`token_to_string`, `Ident::to_string`), except that symbols don't keep the rawness flag
1736 /// or edition, so we have to guess the rawness using the global edition.
1737 pub fn to_ident_string(self) -> String {
1738 Ident::with_dummy_span(self).to_string()
1742 impl fmt::Debug for Symbol {
1743 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1744 fmt::Debug::fmt(self.as_str(), f)
1748 impl fmt::Display for Symbol {
1749 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1750 fmt::Display::fmt(self.as_str(), f)
1754 impl<S: Encoder> Encodable<S> for Symbol {
1755 fn encode(&self, s: &mut S) -> Result<(), S::Error> {
1756 s.emit_str(self.as_str())
1760 impl<D: Decoder> Decodable<D> for Symbol {
1762 fn decode(d: &mut D) -> Symbol {
1763 Symbol::intern(&d.read_str())
1767 impl<CTX> HashStable<CTX> for Symbol {
1769 fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
1770 self.as_str().hash_stable(hcx, hasher);
1774 impl<CTX> ToStableHashKey<CTX> for Symbol {
1775 type KeyType = String;
1777 fn to_stable_hash_key(&self, _: &CTX) -> String {
1778 self.as_str().to_string()
1783 pub(crate) struct Interner(Lock<InternerInner>);
1785 // The `&'static str`s in this type actually point into the arena.
1787 // The `FxHashMap`+`Vec` pair could be replaced by `FxIndexSet`, but #75278
1788 // found that to regress performance up to 2% in some cases. This might be
1789 // revisited after further improvements to `indexmap`.
1791 // This type is private to prevent accidentally constructing more than one
1792 // `Interner` on the same thread, which makes it easy to mixup `Symbol`s
1793 // between `Interner`s.
1795 struct InternerInner {
1796 arena: DroplessArena,
1797 names: FxHashMap<&'static str, Symbol>,
1798 strings: Vec<&'static str>,
1802 fn prefill(init: &[&'static str]) -> Self {
1803 Interner(Lock::new(InternerInner {
1804 strings: init.into(),
1805 names: init.iter().copied().zip((0..).map(Symbol::new)).collect(),
1806 ..Default::default()
1811 fn intern(&self, string: &str) -> Symbol {
1812 let mut inner = self.0.lock();
1813 if let Some(&name) = inner.names.get(string) {
1817 let name = Symbol::new(inner.strings.len() as u32);
1819 // SAFETY: we convert from `&str` to `&[u8]`, clone it into the arena,
1820 // and immediately convert the clone back to `&[u8], all because there
1821 // is no `inner.arena.alloc_str()` method. This is clearly safe.
1823 unsafe { str::from_utf8_unchecked(inner.arena.alloc_slice(string.as_bytes())) };
1825 // SAFETY: we can extend the arena allocation to `'static` because we
1826 // only access these while the arena is still alive.
1827 let string: &'static str = unsafe { &*(string as *const str) };
1828 inner.strings.push(string);
1830 // This second hash table lookup can be avoided by using `RawEntryMut`,
1831 // but this code path isn't hot enough for it to be worth it. See
1832 // #91445 for details.
1833 inner.names.insert(string, name);
1837 // Get the symbol as a string. `Symbol::as_str()` should be used in
1838 // preference to this function.
1839 fn get(&self, symbol: Symbol) -> &str {
1840 self.0.lock().strings[symbol.0.as_usize()]
1844 // This module has a very short name because it's used a lot.
1845 /// This module contains all the defined keyword `Symbol`s.
1847 /// Given that `kw` is imported, use them like `kw::keyword_name`.
1848 /// For example `kw::Loop` or `kw::Break`.
1850 pub use super::kw_generated::*;
1853 // This module has a very short name because it's used a lot.
1854 /// This module contains all the defined non-keyword `Symbol`s.
1856 /// Given that `sym` is imported, use them like `sym::symbol_name`.
1857 /// For example `sym::rustfmt` or `sym::u8`.
1860 use std::convert::TryInto;
1863 pub use super::sym_generated::*;
1865 // Used from a macro in `librustc_feature/accepted.rs`
1866 pub use super::kw::MacroRules as macro_rules;
1868 /// Get the symbol for an integer.
1870 /// The first few non-negative integers each have a static symbol and therefore
1872 pub fn integer<N: TryInto<usize> + Copy + ToString>(n: N) -> Symbol {
1873 if let Result::Ok(idx) = n.try_into() {
1875 return Symbol::new(super::SYMBOL_DIGITS_BASE + idx as u32);
1878 Symbol::intern(&n.to_string())
1883 fn is_special(self) -> bool {
1884 self <= kw::Underscore
1887 fn is_used_keyword_always(self) -> bool {
1888 self >= kw::As && self <= kw::While
1891 fn is_used_keyword_conditional(self, edition: impl FnOnce() -> Edition) -> bool {
1892 (self >= kw::Async && self <= kw::Dyn) && edition() >= Edition::Edition2018
1895 fn is_unused_keyword_always(self) -> bool {
1896 self >= kw::Abstract && self <= kw::Yield
1899 fn is_unused_keyword_conditional(self, edition: impl FnOnce() -> Edition) -> bool {
1900 self == kw::Try && edition() >= Edition::Edition2018
1903 pub fn is_reserved(self, edition: impl Copy + FnOnce() -> Edition) -> bool {
1905 || self.is_used_keyword_always()
1906 || self.is_unused_keyword_always()
1907 || self.is_used_keyword_conditional(edition)
1908 || self.is_unused_keyword_conditional(edition)
1911 /// A keyword or reserved identifier that can be used as a path segment.
1912 pub fn is_path_segment_keyword(self) -> bool {
1914 || self == kw::SelfLower
1915 || self == kw::SelfUpper
1916 || self == kw::Crate
1917 || self == kw::PathRoot
1918 || self == kw::DollarCrate
1921 /// Returns `true` if the symbol is `true` or `false`.
1922 pub fn is_bool_lit(self) -> bool {
1923 self == kw::True || self == kw::False
1926 /// Returns `true` if this symbol can be a raw identifier.
1927 pub fn can_be_raw(self) -> bool {
1928 self != kw::Empty && self != kw::Underscore && !self.is_path_segment_keyword()
1933 // Returns `true` for reserved identifiers used internally for elided lifetimes,
1934 // unnamed method parameters, crate root module, error recovery etc.
1935 pub fn is_special(self) -> bool {
1936 self.name.is_special()
1939 /// Returns `true` if the token is a keyword used in the language.
1940 pub fn is_used_keyword(self) -> bool {
1941 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1942 self.name.is_used_keyword_always()
1943 || self.name.is_used_keyword_conditional(|| self.span.edition())
1946 /// Returns `true` if the token is a keyword reserved for possible future use.
1947 pub fn is_unused_keyword(self) -> bool {
1948 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1949 self.name.is_unused_keyword_always()
1950 || self.name.is_unused_keyword_conditional(|| self.span.edition())
1953 /// Returns `true` if the token is either a special identifier or a keyword.
1954 pub fn is_reserved(self) -> bool {
1955 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1956 self.name.is_reserved(|| self.span.edition())
1959 /// A keyword or reserved identifier that can be used as a path segment.
1960 pub fn is_path_segment_keyword(self) -> bool {
1961 self.name.is_path_segment_keyword()
1964 /// We see this identifier in a normal identifier position, like variable name or a type.
1965 /// How was it written originally? Did it use the raw form? Let's try to guess.
1966 pub fn is_raw_guess(self) -> bool {
1967 self.name.can_be_raw() && self.is_reserved()