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
241 ProceduralMasqueradeDummyType,
266 SubdiagnosticMessage,
296 aarch64_target_feature,
297 aarch64_ver_target_feature,
301 abi_c_cmse_nonsecure_call,
303 abi_msp430_interrupt,
317 advanced_slice_patterns,
333 allow_internal_unsafe,
334 allow_internal_unstable,
342 arbitrary_enum_discriminant,
343 arbitrary_self_types,
355 asm_experimental_arch,
363 assert_receiver_is_total_eq,
367 associated_const_equality,
369 associated_type_bounds,
370 associated_type_defaults,
383 augmented_assignments,
385 automatically_derived,
387 avx512_target_feature,
395 bind_by_move_pattern_guards,
407 borrowck_graphviz_format,
408 borrowck_graphviz_postflow,
409 borrowck_graphviz_preflow,
414 braced_empty_structs,
426 capture_disjoint_fields,
443 cfg_target_has_atomic,
444 cfg_target_has_atomic_equal_alignment,
445 cfg_target_has_atomic_load_store,
446 cfg_target_thread_local,
458 closure_to_fn_coercion,
459 closure_track_caller,
463 cmpxchg16b_target_feature,
464 cmse_nonsecure_entry,
471 compare_exchange_weak,
481 conservative_impl_trait,
485 const_compare_raw_pointers,
490 const_eval_select_ct,
491 const_evaluatable_checked,
494 const_fn_floating_point_arithmetic,
495 const_fn_fn_ptr_basics,
496 const_fn_trait_bound,
502 const_generic_defaults,
504 const_generics_defaults,
507 const_in_array_repeat_expressions,
514 const_precise_live_drops,
516 const_raw_ptr_to_usize_cast,
519 const_trait_bound_opt_out,
536 core_panic_2015_macro,
547 crate_visibility_modifier,
548 crt_dash_static: "crt-static",
557 custom_inner_attributes,
558 custom_test_frameworks,
565 debug_assert_eq_macro,
567 debug_assert_ne_macro,
576 default_alloc_error_handler,
577 default_lib_allocator,
578 default_method_body_is_const,
579 default_type_parameter_fallback,
581 delay_span_bug_from_inside_query,
585 deprecated_suggestion,
593 destructuring_assignment,
614 document_private_items,
616 dotdot_in_tuple_patterns,
617 dotdoteq_in_patterns,
625 dropck_parametricity,
636 emit_enum_variant_arg,
648 ermsb_target_feature,
652 exclusive_range_pattern,
653 exhaustive_integer_patterns,
662 explicit_generic_args_with_impl_trait,
665 extended_key_value_attributes,
666 extern_absolute_paths,
667 extern_crate_item_prelude,
690 field_init_shorthand,
697 float_to_int_unchecked,
730 from_size_align_unchecked,
747 generic_associated_types,
748 generic_associated_types_extended,
756 half_open_range_patterns,
758 hexagon_target_feature,
760 homogeneous_aggregate,
777 if_while_or_patterns,
779 impl_header_lifetime_elision,
782 impl_trait_in_bindings,
792 inclusive_range_syntax,
795 infer_outlives_requirements,
796 infer_static_outlives_requirements,
797 inherent_associated_types,
811 irrefutable_let_patterns,
815 issue_5723_bootstrap,
816 issue_tracker_base_url,
831 lazy_normalization_consts,
846 link_llvm_intrinsics,
867 macro_at_most_once_rep,
868 macro_attributes_in_derive_output,
871 macro_lifetime_matcher,
872 macro_literal_matcher,
885 match_beginning_vert,
886 match_default_bindings,
916 min_type_alias_impl_trait,
927 more_qualified_paths,
929 movbe_target_feature,
941 native_link_modifiers,
942 native_link_modifiers_as_needed,
943 native_link_modifiers_bundle,
944 native_link_modifiers_verbatim,
945 native_link_modifiers_whole_archive,
984 non_exhaustive_omitted_patterns_lint,
996 object_safe_for_dispatch,
999 omit_gdb_pretty_printer_section,
1008 optin_builtin_traits,
1017 overlapping_marker_traits,
1029 panic_implementation,
1044 pattern_parentheses,
1047 platform_intrinsics,
1056 post_dash_lto: "post-lto",
1057 powerpc_target_feature,
1062 pre_dash_lto: "pre-lto",
1063 precise_pointer_size_matching,
1067 prefetch_read_instruction,
1068 prefetch_write_data,
1069 prefetch_write_instruction,
1077 proc_dash_macro: "proc-macro",
1079 proc_macro_attribute,
1080 proc_macro_def_site,
1085 proc_macro_internals,
1087 proc_macro_non_items,
1088 proc_macro_path_invoc,
1097 ptr_offset_from_unsigned,
1105 quad_precision_float,
1108 range_inclusive_new,
1113 re_rebalance_coherence,
1116 read_enum_variant_arg,
1124 reexport_test_harness_main,
1125 ref_unwind_safe_trait,
1142 relaxed_struct_unsize,
1158 riscv_target_feature,
1177 rust_eh_catch_typeinfo,
1178 rust_eh_personality,
1179 rust_eh_register_frames,
1180 rust_eh_unregister_frames,
1184 rustc_allocator_nounwind,
1185 rustc_allow_const_fn_unstable,
1186 rustc_allow_incoherent_impl,
1189 rustc_builtin_macro,
1190 rustc_capture_analysis,
1192 rustc_coherence_is_core,
1194 rustc_const_unstable,
1195 rustc_conversion_suggestion,
1197 rustc_diagnostic_item,
1198 rustc_diagnostic_macros,
1200 rustc_do_not_const_check,
1202 rustc_dump_env_program_clauses,
1203 rustc_dump_program_clauses,
1204 rustc_dump_user_substs,
1207 rustc_evaluate_where_clauses,
1208 rustc_expected_cgu_reuse,
1209 rustc_has_incoherent_inherent_impls,
1210 rustc_if_this_changed,
1211 rustc_inherit_overflow_checks,
1212 rustc_insignificant_dtor,
1214 rustc_layout_scalar_valid_range_end,
1215 rustc_layout_scalar_valid_range_start,
1216 rustc_legacy_const_generics,
1217 rustc_lint_diagnostics,
1218 rustc_lint_query_instability,
1219 rustc_macro_transparency,
1222 rustc_must_implement_one_of,
1223 rustc_nonnull_optimization_guaranteed,
1224 rustc_object_lifetime_default,
1225 rustc_on_unimplemented,
1228 rustc_partition_codegened,
1229 rustc_partition_reused,
1230 rustc_pass_by_value,
1232 rustc_peek_definite_init,
1233 rustc_peek_liveness,
1234 rustc_peek_maybe_init,
1235 rustc_peek_maybe_uninit,
1236 rustc_polymorphize_error,
1238 rustc_proc_macro_decls,
1241 rustc_reservation_impl,
1243 rustc_skip_array_during_method_dispatch,
1244 rustc_specialization_trait,
1246 rustc_std_internal_symbol,
1247 rustc_strict_coherence,
1250 rustc_then_this_would_need,
1251 rustc_trivial_field_reads,
1252 rustc_unsafe_specialization_marker,
1257 rvalue_static_promotion,
1308 simd_reduce_add_ordered,
1309 simd_reduce_add_unordered,
1314 simd_reduce_max_nanless,
1316 simd_reduce_min_nanless,
1317 simd_reduce_mul_ordered,
1318 simd_reduce_mul_unordered,
1323 simd_saturating_add,
1324 simd_saturating_sub,
1327 simd_select_bitmask,
1355 sse4a_target_feature,
1367 std_panic_2015_macro,
1370 stmt_expr_attributes,
1371 stop_after_dataflow,
1374 str_split_whitespace,
1381 struct_field_attributes,
1404 target_has_atomic_equal_alignment,
1405 target_has_atomic_load_store,
1407 target_pointer_width,
1408 target_target_vendor,
1409 target_thread_local,
1415 termination_trait_test,
1418 test_accepted_feature,
1420 test_removed_feature,
1428 thumb_mode: "thumb-mode",
1456 type_alias_enum_variants,
1457 type_alias_impl_trait,
1459 type_changing_struct_update,
1469 unaligned_volatile_load,
1470 unaligned_volatile_store,
1479 underscore_const_names,
1481 underscore_lifetimes,
1483 unimplemented_macro,
1485 universal_impl_trait,
1492 unreachable_2015_macro,
1494 unreachable_2021_macro,
1496 unreachable_display,
1498 unrestricted_attribute_tokens,
1499 unsafe_block_in_unsafe_fn,
1501 unsafe_no_drop_flag,
1502 unsafe_pin_internals,
1506 unsized_tuple_coercion,
1510 unused_qualifications,
1536 visible_private_types,
1538 volatile_copy_memory,
1539 volatile_copy_nonoverlapping_memory,
1541 volatile_set_memory,
1548 wasm_target_feature,
1553 with_negative_coherence,
1565 yeet_desugar_details,
1572 #[derive(Copy, Clone, Eq, HashStable_Generic, Encodable, Decodable)]
1580 /// Constructs a new identifier from a symbol and a span.
1581 pub const fn new(name: Symbol, span: Span) -> Ident {
1582 Ident { name, span }
1585 /// Constructs a new identifier with a dummy span.
1587 pub const fn with_dummy_span(name: Symbol) -> Ident {
1588 Ident::new(name, DUMMY_SP)
1592 pub fn empty() -> Ident {
1593 Ident::with_dummy_span(kw::Empty)
1596 /// Maps a string to an identifier with a dummy span.
1597 pub fn from_str(string: &str) -> Ident {
1598 Ident::with_dummy_span(Symbol::intern(string))
1601 /// Maps a string and a span to an identifier.
1602 pub fn from_str_and_span(string: &str, span: Span) -> Ident {
1603 Ident::new(Symbol::intern(string), span)
1606 /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
1607 pub fn with_span_pos(self, span: Span) -> Ident {
1608 Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
1611 pub fn without_first_quote(self) -> Ident {
1612 Ident::new(Symbol::intern(self.as_str().trim_start_matches('\'')), self.span)
1615 /// "Normalize" ident for use in comparisons using "item hygiene".
1616 /// Identifiers with same string value become same if they came from the same macro 2.0 macro
1617 /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
1618 /// different macro 2.0 macros.
1619 /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
1620 pub fn normalize_to_macros_2_0(self) -> Ident {
1621 Ident::new(self.name, self.span.normalize_to_macros_2_0())
1624 /// "Normalize" ident for use in comparisons using "local variable hygiene".
1625 /// Identifiers with same string value become same if they came from the same non-transparent
1626 /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
1627 /// non-transparent macros.
1628 /// Technically, this operation strips all transparent marks from ident's syntactic context.
1629 pub fn normalize_to_macro_rules(self) -> Ident {
1630 Ident::new(self.name, self.span.normalize_to_macro_rules())
1633 /// Access the underlying string. This is a slowish operation because it
1634 /// requires locking the symbol interner.
1636 /// Note that the lifetime of the return value is a lie. See
1637 /// `Symbol::as_str()` for details.
1638 pub fn as_str(&self) -> &str {
1643 impl PartialEq for Ident {
1644 fn eq(&self, rhs: &Self) -> bool {
1645 self.name == rhs.name && self.span.eq_ctxt(rhs.span)
1649 impl Hash for Ident {
1650 fn hash<H: Hasher>(&self, state: &mut H) {
1651 self.name.hash(state);
1652 self.span.ctxt().hash(state);
1656 impl fmt::Debug for Ident {
1657 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1658 fmt::Display::fmt(self, f)?;
1659 fmt::Debug::fmt(&self.span.ctxt(), f)
1663 /// This implementation is supposed to be used in error messages, so it's expected to be identical
1664 /// to printing the original identifier token written in source code (`token_to_string`),
1665 /// except that AST identifiers don't keep the rawness flag, so we have to guess it.
1666 impl fmt::Display for Ident {
1667 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1668 fmt::Display::fmt(&IdentPrinter::new(self.name, self.is_raw_guess(), None), f)
1672 /// This is the most general way to print identifiers.
1673 /// AST pretty-printer is used as a fallback for turning AST structures into token streams for
1674 /// proc macros. Additionally, proc macros may stringify their input and expect it survive the
1675 /// stringification (especially true for proc macro derives written between Rust 1.15 and 1.30).
1676 /// So we need to somehow pretty-print `$crate` in a way preserving at least some of its
1677 /// hygiene data, most importantly name of the crate it refers to.
1678 /// As a result we print `$crate` as `crate` if it refers to the local crate
1679 /// and as `::other_crate_name` if it refers to some other crate.
1680 /// Note, that this is only done if the ident token is printed from inside of AST pretty-printing,
1681 /// but not otherwise. Pretty-printing is the only way for proc macros to discover token contents,
1682 /// so we should not perform this lossy conversion if the top level call to the pretty-printer was
1683 /// done for a token stream or a single token.
1684 pub struct IdentPrinter {
1687 /// Span used for retrieving the crate name to which `$crate` refers to,
1688 /// if this field is `None` then the `$crate` conversion doesn't happen.
1689 convert_dollar_crate: Option<Span>,
1693 /// The most general `IdentPrinter` constructor. Do not use this.
1694 pub fn new(symbol: Symbol, is_raw: bool, convert_dollar_crate: Option<Span>) -> IdentPrinter {
1695 IdentPrinter { symbol, is_raw, convert_dollar_crate }
1698 /// This implementation is supposed to be used when printing identifiers
1699 /// as a part of pretty-printing for larger AST pieces.
1700 /// Do not use this either.
1701 pub fn for_ast_ident(ident: Ident, is_raw: bool) -> IdentPrinter {
1702 IdentPrinter::new(ident.name, is_raw, Some(ident.span))
1706 impl fmt::Display for IdentPrinter {
1707 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1710 } else if self.symbol == kw::DollarCrate {
1711 if let Some(span) = self.convert_dollar_crate {
1712 let converted = span.ctxt().dollar_crate_name();
1713 if !converted.is_path_segment_keyword() {
1716 return fmt::Display::fmt(&converted, f);
1719 fmt::Display::fmt(&self.symbol, f)
1723 /// An newtype around `Ident` that calls [Ident::normalize_to_macro_rules] on
1725 // FIXME(matthewj, petrochenkov) Use this more often, add a similar
1726 // `ModernIdent` struct and use that as well.
1727 #[derive(Copy, Clone, Eq, PartialEq, Hash)]
1728 pub struct MacroRulesNormalizedIdent(Ident);
1730 impl MacroRulesNormalizedIdent {
1731 pub fn new(ident: Ident) -> Self {
1732 Self(ident.normalize_to_macro_rules())
1736 impl fmt::Debug for MacroRulesNormalizedIdent {
1737 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1738 fmt::Debug::fmt(&self.0, f)
1742 impl fmt::Display for MacroRulesNormalizedIdent {
1743 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1744 fmt::Display::fmt(&self.0, f)
1748 /// An interned string.
1750 /// Internally, a `Symbol` is implemented as an index, and all operations
1751 /// (including hashing, equality, and ordering) operate on that index. The use
1752 /// of `rustc_index::newtype_index!` means that `Option<Symbol>` only takes up 4 bytes,
1753 /// because `rustc_index::newtype_index!` reserves the last 256 values for tagging purposes.
1755 /// Note that `Symbol` cannot directly be a `rustc_index::newtype_index!` because it
1756 /// implements `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
1757 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
1758 pub struct Symbol(SymbolIndex);
1760 rustc_index::newtype_index! {
1761 struct SymbolIndex { .. }
1765 const fn new(n: u32) -> Self {
1766 Symbol(SymbolIndex::from_u32(n))
1769 /// Maps a string to its interned representation.
1770 pub fn intern(string: &str) -> Self {
1771 with_session_globals(|session_globals| session_globals.symbol_interner.intern(string))
1774 /// Access the underlying string. This is a slowish operation because it
1775 /// requires locking the symbol interner.
1777 /// Note that the lifetime of the return value is a lie. It's not the same
1778 /// as `&self`, but actually tied to the lifetime of the underlying
1779 /// interner. Interners are long-lived, and there are very few of them, and
1780 /// this function is typically used for short-lived things, so in practice
1781 /// it works out ok.
1782 pub fn as_str(&self) -> &str {
1783 with_session_globals(|session_globals| unsafe {
1784 std::mem::transmute::<&str, &str>(session_globals.symbol_interner.get(*self))
1788 pub fn as_u32(self) -> u32 {
1792 pub fn is_empty(self) -> bool {
1796 /// This method is supposed to be used in error messages, so it's expected to be
1797 /// identical to printing the original identifier token written in source code
1798 /// (`token_to_string`, `Ident::to_string`), except that symbols don't keep the rawness flag
1799 /// or edition, so we have to guess the rawness using the global edition.
1800 pub fn to_ident_string(self) -> String {
1801 Ident::with_dummy_span(self).to_string()
1805 impl fmt::Debug for Symbol {
1806 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1807 fmt::Debug::fmt(self.as_str(), f)
1811 impl fmt::Display for Symbol {
1812 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1813 fmt::Display::fmt(self.as_str(), f)
1817 impl<S: Encoder> Encodable<S> for Symbol {
1818 fn encode(&self, s: &mut S) {
1819 s.emit_str(self.as_str());
1823 impl<D: Decoder> Decodable<D> for Symbol {
1825 fn decode(d: &mut D) -> Symbol {
1826 Symbol::intern(&d.read_str())
1830 impl<CTX> HashStable<CTX> for Symbol {
1832 fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
1833 self.as_str().hash_stable(hcx, hasher);
1837 impl<CTX> ToStableHashKey<CTX> for Symbol {
1838 type KeyType = String;
1840 fn to_stable_hash_key(&self, _: &CTX) -> String {
1841 self.as_str().to_string()
1846 pub(crate) struct Interner(Lock<InternerInner>);
1848 // The `&'static str`s in this type actually point into the arena.
1850 // The `FxHashMap`+`Vec` pair could be replaced by `FxIndexSet`, but #75278
1851 // found that to regress performance up to 2% in some cases. This might be
1852 // revisited after further improvements to `indexmap`.
1854 // This type is private to prevent accidentally constructing more than one
1855 // `Interner` on the same thread, which makes it easy to mix up `Symbol`s
1856 // between `Interner`s.
1858 struct InternerInner {
1859 arena: DroplessArena,
1860 names: FxHashMap<&'static str, Symbol>,
1861 strings: Vec<&'static str>,
1865 fn prefill(init: &[&'static str]) -> Self {
1866 Interner(Lock::new(InternerInner {
1867 strings: init.into(),
1868 names: init.iter().copied().zip((0..).map(Symbol::new)).collect(),
1869 ..Default::default()
1874 fn intern(&self, string: &str) -> Symbol {
1875 let mut inner = self.0.lock();
1876 if let Some(&name) = inner.names.get(string) {
1880 let name = Symbol::new(inner.strings.len() as u32);
1882 // SAFETY: we convert from `&str` to `&[u8]`, clone it into the arena,
1883 // and immediately convert the clone back to `&[u8], all because there
1884 // is no `inner.arena.alloc_str()` method. This is clearly safe.
1886 unsafe { str::from_utf8_unchecked(inner.arena.alloc_slice(string.as_bytes())) };
1888 // SAFETY: we can extend the arena allocation to `'static` because we
1889 // only access these while the arena is still alive.
1890 let string: &'static str = unsafe { &*(string as *const str) };
1891 inner.strings.push(string);
1893 // This second hash table lookup can be avoided by using `RawEntryMut`,
1894 // but this code path isn't hot enough for it to be worth it. See
1895 // #91445 for details.
1896 inner.names.insert(string, name);
1900 // Get the symbol as a string. `Symbol::as_str()` should be used in
1901 // preference to this function.
1902 fn get(&self, symbol: Symbol) -> &str {
1903 self.0.lock().strings[symbol.0.as_usize()]
1907 // This module has a very short name because it's used a lot.
1908 /// This module contains all the defined keyword `Symbol`s.
1910 /// Given that `kw` is imported, use them like `kw::keyword_name`.
1911 /// For example `kw::Loop` or `kw::Break`.
1913 pub use super::kw_generated::*;
1916 // This module has a very short name because it's used a lot.
1917 /// This module contains all the defined non-keyword `Symbol`s.
1919 /// Given that `sym` is imported, use them like `sym::symbol_name`.
1920 /// For example `sym::rustfmt` or `sym::u8`.
1923 use std::convert::TryInto;
1926 pub use super::sym_generated::*;
1928 // Used from a macro in `librustc_feature/accepted.rs`
1929 pub use super::kw::MacroRules as macro_rules;
1931 /// Get the symbol for an integer.
1933 /// The first few non-negative integers each have a static symbol and therefore
1935 pub fn integer<N: TryInto<usize> + Copy + ToString>(n: N) -> Symbol {
1936 if let Result::Ok(idx) = n.try_into() {
1938 return Symbol::new(super::SYMBOL_DIGITS_BASE + idx as u32);
1941 Symbol::intern(&n.to_string())
1946 fn is_special(self) -> bool {
1947 self <= kw::Underscore
1950 fn is_used_keyword_always(self) -> bool {
1951 self >= kw::As && self <= kw::While
1954 fn is_used_keyword_conditional(self, edition: impl FnOnce() -> Edition) -> bool {
1955 (self >= kw::Async && self <= kw::Dyn) && edition() >= Edition::Edition2018
1958 fn is_unused_keyword_always(self) -> bool {
1959 self >= kw::Abstract && self <= kw::Yield
1962 fn is_unused_keyword_conditional(self, edition: impl FnOnce() -> Edition) -> bool {
1963 self == kw::Try && edition() >= Edition::Edition2018
1966 pub fn is_reserved(self, edition: impl Copy + FnOnce() -> Edition) -> bool {
1968 || self.is_used_keyword_always()
1969 || self.is_unused_keyword_always()
1970 || self.is_used_keyword_conditional(edition)
1971 || self.is_unused_keyword_conditional(edition)
1974 /// A keyword or reserved identifier that can be used as a path segment.
1975 pub fn is_path_segment_keyword(self) -> bool {
1977 || self == kw::SelfLower
1978 || self == kw::SelfUpper
1979 || self == kw::Crate
1980 || self == kw::PathRoot
1981 || self == kw::DollarCrate
1984 /// Returns `true` if the symbol is `true` or `false`.
1985 pub fn is_bool_lit(self) -> bool {
1986 self == kw::True || self == kw::False
1989 /// Returns `true` if this symbol can be a raw identifier.
1990 pub fn can_be_raw(self) -> bool {
1991 self != kw::Empty && self != kw::Underscore && !self.is_path_segment_keyword()
1996 // Returns `true` for reserved identifiers used internally for elided lifetimes,
1997 // unnamed method parameters, crate root module, error recovery etc.
1998 pub fn is_special(self) -> bool {
1999 self.name.is_special()
2002 /// Returns `true` if the token is a keyword used in the language.
2003 pub fn is_used_keyword(self) -> bool {
2004 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
2005 self.name.is_used_keyword_always()
2006 || self.name.is_used_keyword_conditional(|| self.span.edition())
2009 /// Returns `true` if the token is a keyword reserved for possible future use.
2010 pub fn is_unused_keyword(self) -> bool {
2011 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
2012 self.name.is_unused_keyword_always()
2013 || self.name.is_unused_keyword_conditional(|| self.span.edition())
2016 /// Returns `true` if the token is either a special identifier or a keyword.
2017 pub fn is_reserved(self) -> bool {
2018 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
2019 self.name.is_reserved(|| self.span.edition())
2022 /// A keyword or reserved identifier that can be used as a path segment.
2023 pub fn is_path_segment_keyword(self) -> bool {
2024 self.name.is_path_segment_keyword()
2027 /// We see this identifier in a normal identifier position, like variable name or a type.
2028 /// How was it written originally? Did it use the raw form? Let's try to guess.
2029 pub fn is_raw_guess(self) -> bool {
2030 self.name.can_be_raw() && self.is_reserved()