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_macros::HashStable_Generic;
9 use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
11 use std::cmp::{Ord, PartialEq, PartialOrd};
13 use std::hash::{Hash, Hasher};
16 use crate::{Span, DUMMY_SP, SESSION_GLOBALS};
21 // The proc macro code for this is in `src/librustc_macros/src/symbols.rs`.
23 // After modifying this list adjust `is_special`, `is_used_keyword`/`is_unused_keyword`,
24 // this should be rarely necessary though if the keywords are kept in alphabetic order.
26 // Special reserved identifiers used internally for elided lifetimes,
27 // unnamed method parameters, crate root module, error recovery etc.
30 DollarCrate: "$crate",
33 // Keywords that are used in stable Rust.
70 // Keywords that are used in unstable Rust or reserved for future use.
84 // Edition-specific keywords that are used in stable Rust.
85 Async: "async", // >= 2018 Edition only
86 Await: "await", // >= 2018 Edition only
87 Dyn: "dyn", // >= 2018 Edition only
89 // Edition-specific keywords that are used in unstable Rust or reserved for future use.
90 Try: "try", // >= 2018 Edition only
92 // Special lifetime names
93 UnderscoreLifetime: "'_",
94 StaticLifetime: "'static",
96 // Weak keywords, have special meaning only in specific contexts.
100 MacroRules: "macro_rules",
105 // Pre-interned symbols that can be referred to with `rustc_span::sym::*`.
107 // The symbol is the stringified identifier unless otherwise specified, in
108 // which case the name should mention the non-identifier punctuation.
109 // E.g. `sym::proc_dash_macro` represents "proc-macro", and it shouldn't be
110 // called `sym::proc_macro` because then it's easy to mistakenly think it
111 // represents "proc_macro".
113 // As well as the symbols listed, there are symbols for the strings
114 // "0", "1", ..., "9", which are accessible via `sym::integer`.
116 // The proc macro will abort if symbols are not in alphabetical order (as
117 // defined by `impl Ord for str`) or if any symbols are duplicated. Vim
118 // users can sort the list by selecting it and executing the command
119 // `:'<,'>!LC_ALL=C sort`.
121 // There is currently no checking that all symbols are used; that would be
179 ProceduralMasqueradeDummyType,
217 aarch64_target_feature,
222 abi_msp430_interrupt,
235 advanced_slice_patterns,
250 allow_internal_unsafe,
251 allow_internal_unstable,
252 allow_internal_unstable_backcompat_hack,
258 arbitrary_enum_discriminant,
259 arbitrary_self_types,
271 assert_receiver_is_total_eq,
275 associated_type_bounds,
276 associated_type_defaults,
287 augmented_assignments,
289 automatically_derived,
290 avx512_target_feature,
296 bind_by_move_pattern_guards,
307 borrowck_graphviz_format,
308 borrowck_graphviz_postflow,
309 borrowck_graphviz_preflow,
313 braced_empty_structs,
323 capture_disjoint_fields,
335 cfg_target_has_atomic,
336 cfg_target_thread_local,
346 closure_to_fn_coercion,
348 cmpxchg16b_target_feature,
349 cmse_nonsecure_entry,
357 conservative_impl_trait,
360 const_compare_raw_pointers,
363 const_evaluatable_checked,
366 const_fn_floating_point_arithmetic,
367 const_fn_fn_ptr_basics,
373 const_in_array_repeat_expressions,
379 const_precise_live_drops,
382 const_raw_ptr_to_usize_cast,
384 const_trait_bound_opt_out,
407 crate_visibility_modifier,
408 crt_dash_static: "crt-static",
417 custom_inner_attributes,
418 custom_test_frameworks,
432 default_alloc_error_handler,
433 default_lib_allocator,
434 default_type_parameter_fallback,
436 delay_span_bug_from_inside_query,
444 destructuring_assignment,
460 document_private_items,
461 dotdot_in_tuple_patterns,
462 dotdoteq_in_patterns,
470 dropck_parametricity,
477 emit_enum_variant_arg,
485 ermsb_target_feature,
490 exclusive_range_pattern,
491 exhaustive_integer_patterns,
502 extended_key_value_attributes,
503 extern_absolute_paths,
504 extern_crate_item_prelude,
526 field_init_shorthand,
531 float_to_int_unchecked,
558 from_size_align_unchecked,
571 generic_associated_types,
578 half_open_range_patterns,
580 hexagon_target_feature,
582 homogeneous_aggregate,
598 if_while_or_patterns,
600 impl_header_lifetime_elision,
603 impl_trait_in_bindings,
609 inclusive_range_syntax,
612 infer_outlives_requirements,
613 infer_static_outlives_requirements,
623 irrefutable_let_patterns,
627 issue_5723_bootstrap,
628 issue_tracker_base_url,
640 lazy_normalization_consts,
652 link_llvm_intrinsics,
671 macro_at_most_once_rep,
674 macro_lifetime_matcher,
675 macro_literal_matcher,
687 match_beginning_vert,
688 match_default_bindings,
714 movbe_target_feature,
764 nontrapping_dash_fptoint: "nontrapping-fptoint",
769 object_safe_for_dispatch,
772 omit_gdb_pretty_printer_section,
781 optin_builtin_traits,
790 overlapping_marker_traits,
798 panic_implementation,
825 post_dash_lto: "post-lto",
826 powerpc_target_feature,
831 pre_dash_lto: "pre-lto",
832 precise_pointer_size_matching,
836 prefetch_read_instruction,
838 prefetch_write_instruction,
843 proc_dash_macro: "proc-macro",
845 proc_macro_attribute,
851 proc_macro_internals,
853 proc_macro_non_items,
854 proc_macro_path_invoc,
866 quad_precision_float,
873 re_rebalance_coherence,
876 read_enum_variant_arg,
884 reexport_test_harness_main,
912 riscv_target_feature,
924 rust_eh_catch_typeinfo,
926 rust_eh_register_frames,
927 rust_eh_unregister_frames,
931 rustc_allocator_nounwind,
932 rustc_allow_const_fn_unstable,
933 rustc_args_required_const,
936 rustc_capture_analysis,
939 rustc_const_unstable,
940 rustc_conversion_suggestion,
943 rustc_diagnostic_item,
944 rustc_diagnostic_macros,
947 rustc_dump_env_program_clauses,
948 rustc_dump_program_clauses,
949 rustc_dump_user_substs,
951 rustc_expected_cgu_reuse,
952 rustc_if_this_changed,
953 rustc_inherit_overflow_checks,
955 rustc_layout_scalar_valid_range_end,
956 rustc_layout_scalar_valid_range_start,
957 rustc_macro_transparency,
959 rustc_nonnull_optimization_guaranteed,
960 rustc_object_lifetime_default,
961 rustc_on_unimplemented,
964 rustc_partition_codegened,
965 rustc_partition_reused,
967 rustc_peek_definite_init,
968 rustc_peek_indirectly_mutable,
970 rustc_peek_maybe_init,
971 rustc_peek_maybe_uninit,
972 rustc_polymorphize_error,
974 rustc_proc_macro_decls,
977 rustc_reservation_impl,
979 rustc_specialization_trait,
981 rustc_std_internal_symbol,
985 rustc_then_this_would_need,
986 rustc_unsafe_specialization_marker,
989 rvalue_static_promotion,
1037 simd_reduce_add_ordered,
1038 simd_reduce_add_unordered,
1043 simd_reduce_max_nanless,
1045 simd_reduce_min_nanless,
1046 simd_reduce_mul_ordered,
1047 simd_reduce_mul_unordered,
1051 simd_saturating_add,
1052 simd_saturating_sub,
1055 simd_select_bitmask,
1081 sse4a_target_feature,
1094 stmt_expr_attributes,
1095 stop_after_dataflow,
1100 struct_field_attributes,
1122 target_has_atomic_equal_alignment,
1123 target_has_atomic_load_store,
1125 target_pointer_width,
1126 target_target_vendor,
1127 target_thread_local,
1133 termination_trait_test,
1136 test_accepted_feature,
1138 test_removed_feature,
1163 type_alias_enum_variants,
1164 type_alias_impl_trait,
1175 unaligned_volatile_load,
1176 unaligned_volatile_store,
1185 underscore_const_names,
1187 underscore_lifetimes,
1190 universal_impl_trait,
1197 unrestricted_attribute_tokens,
1198 unsafe_block_in_unsafe_fn,
1200 unsafe_no_drop_flag,
1204 unsized_tuple_coercion,
1207 unused_qualifications,
1229 visible_private_types,
1231 volatile_copy_memory,
1232 volatile_copy_nonoverlapping_memory,
1234 volatile_set_memory,
1240 wasm_target_feature,
1255 #[derive(Copy, Clone, Eq, HashStable_Generic, Encodable, Decodable)]
1263 /// Constructs a new identifier from a symbol and a span.
1264 pub const fn new(name: Symbol, span: Span) -> Ident {
1265 Ident { name, span }
1268 /// Constructs a new identifier with a dummy span.
1270 pub const fn with_dummy_span(name: Symbol) -> Ident {
1271 Ident::new(name, DUMMY_SP)
1275 pub fn invalid() -> Ident {
1276 Ident::with_dummy_span(kw::Invalid)
1279 /// Maps a string to an identifier with a dummy span.
1280 pub fn from_str(string: &str) -> Ident {
1281 Ident::with_dummy_span(Symbol::intern(string))
1284 /// Maps a string and a span to an identifier.
1285 pub fn from_str_and_span(string: &str, span: Span) -> Ident {
1286 Ident::new(Symbol::intern(string), span)
1289 /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
1290 pub fn with_span_pos(self, span: Span) -> Ident {
1291 Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
1294 pub fn without_first_quote(self) -> Ident {
1295 Ident::new(Symbol::intern(self.as_str().trim_start_matches('\'')), self.span)
1298 /// "Normalize" ident for use in comparisons using "item hygiene".
1299 /// Identifiers with same string value become same if they came from the same macro 2.0 macro
1300 /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
1301 /// different macro 2.0 macros.
1302 /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
1303 pub fn normalize_to_macros_2_0(self) -> Ident {
1304 Ident::new(self.name, self.span.normalize_to_macros_2_0())
1307 /// "Normalize" ident for use in comparisons using "local variable hygiene".
1308 /// Identifiers with same string value become same if they came from the same non-transparent
1309 /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
1310 /// non-transparent macros.
1311 /// Technically, this operation strips all transparent marks from ident's syntactic context.
1312 pub fn normalize_to_macro_rules(self) -> Ident {
1313 Ident::new(self.name, self.span.normalize_to_macro_rules())
1316 /// Convert the name to a `SymbolStr`. This is a slowish operation because
1317 /// it requires locking the symbol interner.
1318 pub fn as_str(self) -> SymbolStr {
1323 impl PartialEq for Ident {
1324 fn eq(&self, rhs: &Self) -> bool {
1325 self.name == rhs.name && self.span.ctxt() == rhs.span.ctxt()
1329 impl Hash for Ident {
1330 fn hash<H: Hasher>(&self, state: &mut H) {
1331 self.name.hash(state);
1332 self.span.ctxt().hash(state);
1336 impl fmt::Debug for Ident {
1337 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1338 fmt::Display::fmt(self, f)?;
1339 fmt::Debug::fmt(&self.span.ctxt(), f)
1343 /// This implementation is supposed to be used in error messages, so it's expected to be identical
1344 /// to printing the original identifier token written in source code (`token_to_string`),
1345 /// except that AST identifiers don't keep the rawness flag, so we have to guess it.
1346 impl fmt::Display for Ident {
1347 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1348 fmt::Display::fmt(&IdentPrinter::new(self.name, self.is_raw_guess(), None), f)
1352 /// This is the most general way to print identifiers.
1353 /// AST pretty-printer is used as a fallback for turning AST structures into token streams for
1354 /// proc macros. Additionally, proc macros may stringify their input and expect it survive the
1355 /// stringification (especially true for proc macro derives written between Rust 1.15 and 1.30).
1356 /// So we need to somehow pretty-print `$crate` in a way preserving at least some of its
1357 /// hygiene data, most importantly name of the crate it refers to.
1358 /// As a result we print `$crate` as `crate` if it refers to the local crate
1359 /// and as `::other_crate_name` if it refers to some other crate.
1360 /// Note, that this is only done if the ident token is printed from inside of AST pretty-pringing,
1361 /// but not otherwise. Pretty-printing is the only way for proc macros to discover token contents,
1362 /// so we should not perform this lossy conversion if the top level call to the pretty-printer was
1363 /// done for a token stream or a single token.
1364 pub struct IdentPrinter {
1367 /// Span used for retrieving the crate name to which `$crate` refers to,
1368 /// if this field is `None` then the `$crate` conversion doesn't happen.
1369 convert_dollar_crate: Option<Span>,
1373 /// The most general `IdentPrinter` constructor. Do not use this.
1374 pub fn new(symbol: Symbol, is_raw: bool, convert_dollar_crate: Option<Span>) -> IdentPrinter {
1375 IdentPrinter { symbol, is_raw, convert_dollar_crate }
1378 /// This implementation is supposed to be used when printing identifiers
1379 /// as a part of pretty-printing for larger AST pieces.
1380 /// Do not use this either.
1381 pub fn for_ast_ident(ident: Ident, is_raw: bool) -> IdentPrinter {
1382 IdentPrinter::new(ident.name, is_raw, Some(ident.span))
1386 impl fmt::Display for IdentPrinter {
1387 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1390 } else if self.symbol == kw::DollarCrate {
1391 if let Some(span) = self.convert_dollar_crate {
1392 let converted = span.ctxt().dollar_crate_name();
1393 if !converted.is_path_segment_keyword() {
1396 return fmt::Display::fmt(&converted, f);
1399 fmt::Display::fmt(&self.symbol, f)
1403 /// An newtype around `Ident` that calls [Ident::normalize_to_macro_rules] on
1405 // FIXME(matthewj, petrochenkov) Use this more often, add a similar
1406 // `ModernIdent` struct and use that as well.
1407 #[derive(Copy, Clone, Eq, PartialEq, Hash)]
1408 pub struct MacroRulesNormalizedIdent(Ident);
1410 impl MacroRulesNormalizedIdent {
1411 pub fn new(ident: Ident) -> Self {
1412 Self(ident.normalize_to_macro_rules())
1416 impl fmt::Debug for MacroRulesNormalizedIdent {
1417 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1418 fmt::Debug::fmt(&self.0, f)
1422 impl fmt::Display for MacroRulesNormalizedIdent {
1423 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1424 fmt::Display::fmt(&self.0, f)
1428 /// An interned string.
1430 /// Internally, a `Symbol` is implemented as an index, and all operations
1431 /// (including hashing, equality, and ordering) operate on that index. The use
1432 /// of `rustc_index::newtype_index!` means that `Option<Symbol>` only takes up 4 bytes,
1433 /// because `rustc_index::newtype_index!` reserves the last 256 values for tagging purposes.
1435 /// Note that `Symbol` cannot directly be a `rustc_index::newtype_index!` because it
1436 /// implements `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
1437 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
1438 pub struct Symbol(SymbolIndex);
1440 rustc_index::newtype_index! {
1441 pub struct SymbolIndex { .. }
1445 const fn new(n: u32) -> Self {
1446 Symbol(SymbolIndex::from_u32(n))
1449 /// Maps a string to its interned representation.
1450 pub fn intern(string: &str) -> Self {
1451 with_interner(|interner| interner.intern(string))
1454 /// Access the symbol's chars. This is a slowish operation because it
1455 /// requires locking the symbol interner.
1456 pub fn with<F: FnOnce(&str) -> R, R>(self, f: F) -> R {
1457 with_interner(|interner| f(interner.get(self)))
1460 /// Convert to a `SymbolStr`. This is a slowish operation because it
1461 /// requires locking the symbol interner.
1462 pub fn as_str(self) -> SymbolStr {
1463 with_interner(|interner| unsafe {
1464 SymbolStr { string: std::mem::transmute::<&str, &str>(interner.get(self)) }
1468 pub fn as_u32(self) -> u32 {
1472 pub fn is_empty(self) -> bool {
1476 /// This method is supposed to be used in error messages, so it's expected to be
1477 /// identical to printing the original identifier token written in source code
1478 /// (`token_to_string`, `Ident::to_string`), except that symbols don't keep the rawness flag
1479 /// or edition, so we have to guess the rawness using the global edition.
1480 pub fn to_ident_string(self) -> String {
1481 Ident::with_dummy_span(self).to_string()
1485 impl fmt::Debug for Symbol {
1486 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1487 self.with(|str| fmt::Debug::fmt(&str, f))
1491 impl fmt::Display for Symbol {
1492 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1493 self.with(|str| fmt::Display::fmt(&str, f))
1497 impl<S: Encoder> Encodable<S> for Symbol {
1498 fn encode(&self, s: &mut S) -> Result<(), S::Error> {
1499 self.with(|string| s.emit_str(string))
1503 impl<D: Decoder> Decodable<D> for Symbol {
1505 fn decode(d: &mut D) -> Result<Symbol, D::Error> {
1506 Ok(Symbol::intern(&d.read_str()?))
1510 impl<CTX> HashStable<CTX> for Symbol {
1512 fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
1513 self.as_str().hash_stable(hcx, hasher);
1517 impl<CTX> ToStableHashKey<CTX> for Symbol {
1518 type KeyType = SymbolStr;
1521 fn to_stable_hash_key(&self, _: &CTX) -> SymbolStr {
1526 // The `&'static str`s in this type actually point into the arena.
1528 // The `FxHashMap`+`Vec` pair could be replaced by `FxIndexSet`, but #75278
1529 // found that to regress performance up to 2% in some cases. This might be
1530 // revisited after further improvements to `indexmap`.
1532 pub struct Interner {
1533 arena: DroplessArena,
1534 names: FxHashMap<&'static str, Symbol>,
1535 strings: Vec<&'static str>,
1539 fn prefill(init: &[&'static str]) -> Self {
1541 strings: init.into(),
1542 names: init.iter().copied().zip((0..).map(Symbol::new)).collect(),
1543 ..Default::default()
1548 pub fn intern(&mut self, string: &str) -> Symbol {
1549 if let Some(&name) = self.names.get(string) {
1553 let name = Symbol::new(self.strings.len() as u32);
1555 // `from_utf8_unchecked` is safe since we just allocated a `&str` which is known to be
1558 unsafe { str::from_utf8_unchecked(self.arena.alloc_slice(string.as_bytes())) };
1559 // It is safe to extend the arena allocation to `'static` because we only access
1560 // these while the arena is still alive.
1561 let string: &'static str = unsafe { &*(string as *const str) };
1562 self.strings.push(string);
1563 self.names.insert(string, name);
1567 // Get the symbol as a string. `Symbol::as_str()` should be used in
1568 // preference to this function.
1569 pub fn get(&self, symbol: Symbol) -> &str {
1570 self.strings[symbol.0.as_usize()]
1574 // This module has a very short name because it's used a lot.
1575 /// This module contains all the defined keyword `Symbol`s.
1577 /// Given that `kw` is imported, use them like `kw::keyword_name`.
1578 /// For example `kw::Loop` or `kw::Break`.
1580 pub use super::kw_generated::*;
1583 // This module has a very short name because it's used a lot.
1584 /// This module contains all the defined non-keyword `Symbol`s.
1586 /// Given that `sym` is imported, use them like `sym::symbol_name`.
1587 /// For example `sym::rustfmt` or `sym::u8`.
1590 use std::convert::TryInto;
1592 pub use super::sym_generated::*;
1594 // Used from a macro in `librustc_feature/accepted.rs`
1595 pub use super::kw::MacroRules as macro_rules;
1597 /// Get the symbol for an integer.
1599 /// The first few non-negative integers each have a static symbol and therefore
1601 pub fn integer<N: TryInto<usize> + Copy + ToString>(n: N) -> Symbol {
1602 if let Result::Ok(idx) = n.try_into() {
1604 return Symbol::new(super::SYMBOL_DIGITS_BASE + idx as u32);
1607 Symbol::intern(&n.to_string())
1612 fn is_used_keyword_2018(self) -> bool {
1613 self >= kw::Async && self <= kw::Dyn
1616 fn is_unused_keyword_2018(self) -> bool {
1620 /// A keyword or reserved identifier that can be used as a path segment.
1621 pub fn is_path_segment_keyword(self) -> bool {
1623 || self == kw::SelfLower
1624 || self == kw::SelfUpper
1625 || self == kw::Crate
1626 || self == kw::PathRoot
1627 || self == kw::DollarCrate
1630 /// Returns `true` if the symbol is `true` or `false`.
1631 pub fn is_bool_lit(self) -> bool {
1632 self == kw::True || self == kw::False
1635 /// Returns `true` if this symbol can be a raw identifier.
1636 pub fn can_be_raw(self) -> bool {
1637 self != kw::Invalid && self != kw::Underscore && !self.is_path_segment_keyword()
1642 // Returns `true` for reserved identifiers used internally for elided lifetimes,
1643 // unnamed method parameters, crate root module, error recovery etc.
1644 pub fn is_special(self) -> bool {
1645 self.name <= kw::Underscore
1648 /// Returns `true` if the token is a keyword used in the language.
1649 pub fn is_used_keyword(self) -> bool {
1650 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1651 self.name >= kw::As && self.name <= kw::While
1652 || self.name.is_used_keyword_2018() && self.span.rust_2018()
1655 /// Returns `true` if the token is a keyword reserved for possible future use.
1656 pub fn is_unused_keyword(self) -> bool {
1657 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1658 self.name >= kw::Abstract && self.name <= kw::Yield
1659 || self.name.is_unused_keyword_2018() && self.span.rust_2018()
1662 /// Returns `true` if the token is either a special identifier or a keyword.
1663 pub fn is_reserved(self) -> bool {
1664 self.is_special() || self.is_used_keyword() || self.is_unused_keyword()
1667 /// A keyword or reserved identifier that can be used as a path segment.
1668 pub fn is_path_segment_keyword(self) -> bool {
1669 self.name.is_path_segment_keyword()
1672 /// We see this identifier in a normal identifier position, like variable name or a type.
1673 /// How was it written originally? Did it use the raw form? Let's try to guess.
1674 pub fn is_raw_guess(self) -> bool {
1675 self.name.can_be_raw() && self.is_reserved()
1680 fn with_interner<T, F: FnOnce(&mut Interner) -> T>(f: F) -> T {
1681 SESSION_GLOBALS.with(|session_globals| f(&mut *session_globals.symbol_interner.lock()))
1684 /// An alternative to `Symbol`, useful when the chars within the symbol need to
1685 /// be accessed. It deliberately has limited functionality and should only be
1686 /// used for temporary values.
1688 /// Because the interner outlives any thread which uses this type, we can
1689 /// safely treat `string` which points to interner data, as an immortal string,
1690 /// as long as this type never crosses between threads.
1692 // FIXME: ensure that the interner outlives any thread which uses `SymbolStr`,
1693 // by creating a new thread right after constructing the interner.
1694 #[derive(Clone, Eq, PartialOrd, Ord)]
1695 pub struct SymbolStr {
1696 string: &'static str,
1699 // This impl allows a `SymbolStr` to be directly equated with a `String` or
1701 impl<T: std::ops::Deref<Target = str>> std::cmp::PartialEq<T> for SymbolStr {
1702 fn eq(&self, other: &T) -> bool {
1703 self.string == other.deref()
1707 impl !Send for SymbolStr {}
1708 impl !Sync for SymbolStr {}
1710 /// This impl means that if `ss` is a `SymbolStr`:
1711 /// - `*ss` is a `str`;
1712 /// - `&*ss` is a `&str` (and `match &*ss { ... }` is a common pattern).
1713 /// - `&ss as &str` is a `&str`, which means that `&ss` can be passed to a
1714 /// function expecting a `&str`.
1715 impl std::ops::Deref for SymbolStr {
1718 fn deref(&self) -> &str {
1723 impl fmt::Debug for SymbolStr {
1724 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1725 fmt::Debug::fmt(self.string, f)
1729 impl fmt::Display for SymbolStr {
1730 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1731 fmt::Display::fmt(self.string, f)
1735 impl<CTX> HashStable<CTX> for SymbolStr {
1737 fn hash_stable(&self, hcx: &mut CTX, hasher: &mut StableHasher) {
1738 self.string.hash_stable(hcx, hasher)
1742 impl<CTX> ToStableHashKey<CTX> for SymbolStr {
1743 type KeyType = SymbolStr;
1746 fn to_stable_hash_key(&self, _: &CTX) -> SymbolStr {