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 arena::DroplessArena;
6 use rustc_data_structures::fx::FxHashMap;
7 use rustc_data_structures::indexed_vec::Idx;
8 use rustc_data_structures::newtype_index;
9 use rustc_macros::symbols;
10 use serialize::{Decodable, Decoder, Encodable, Encoder};
12 use std::cmp::{PartialEq, Ordering, PartialOrd, Ord};
14 use std::hash::{Hash, Hasher};
17 use crate::hygiene::SyntaxContext;
18 use crate::{Span, DUMMY_SP, GLOBALS};
21 // After modifying this list adjust `is_special`, `is_used_keyword`/`is_unused_keyword`,
22 // this should be rarely necessary though if the keywords are kept in alphabetic order.
24 // Special reserved identifiers used internally for elided lifetimes,
25 // unnamed method parameters, crate root module, error recovery etc.
28 DollarCrate: "$crate",
31 // Keywords that are used in stable Rust.
68 // Keywords that are used in unstable Rust or reserved for future use.
82 // Edition-specific keywords that are used in stable Rust.
83 Dyn: "dyn", // >= 2018 Edition only
85 // Edition-specific keywords that are used in unstable Rust or reserved for future use.
86 Async: "async", // >= 2018 Edition only
87 Await: "await", // >= 2018 Edition only
88 Try: "try", // >= 2018 Edition only
90 // Special lifetime names
91 UnderscoreLifetime: "'_",
92 StaticLifetime: "'static",
94 // Weak keywords, have special meaning only in specific contexts.
98 Existential: "existential",
102 // Symbols that can be referred to with syntax_pos::sym::*. The symbol is
103 // the stringified identifier unless otherwise specified (e.g.
104 // `proc_dash_macro` represents "proc-macro").
106 // As well as the symbols listed, there are symbols for the the strings
107 // "0", "1", ..., "9", which are accessible via `sym::integer`.
109 aarch64_target_feature,
112 abi_msp430_interrupt,
120 advanced_slice_patterns,
132 allow_internal_unsafe,
133 allow_internal_unstable,
134 allow_internal_unstable_backcompat_hack,
138 arbitrary_self_types,
144 associated_type_bounds,
145 associated_type_defaults,
151 augmented_assignments,
152 automatically_derived,
153 avx512_target_feature,
158 bind_by_move_pattern_guards,
161 borrowck_graphviz_postflow,
162 borrowck_graphviz_preflow,
165 braced_empty_structs,
172 cfg_target_has_atomic,
173 cfg_target_thread_local,
180 closure_to_fn_coercion,
182 cmpxchg16b_target_feature,
187 conservative_impl_trait,
189 const_compare_raw_pointers,
198 const_raw_ptr_to_usize_cast,
211 crate_visibility_modifier,
214 custom_inner_attributes,
215 custom_test_frameworks,
220 default_lib_allocator,
221 default_type_parameter_fallback,
235 document_private_items,
236 dotdoteq_in_patterns,
237 dotdot_in_tuple_patterns,
238 double_braced_crate: "{{crate}}",
239 double_braced_impl: "{{impl}}",
240 double_braced_misc: "{{misc}}",
241 double_braced_closure: "{{closure}}",
242 double_braced_constructor: "{{constructor}}",
243 double_braced_constant: "{{constant}}",
244 double_braced_opaque: "{{opaque}}",
246 dropck_parametricity,
258 exclusive_range_pattern,
259 exhaustive_integer_patterns,
265 extern_absolute_paths,
267 extern_crate_item_prelude,
278 field_init_shorthand,
300 generic_associated_types,
309 hexagon_target_feature,
311 homogeneous_aggregate,
325 if_while_or_patterns,
327 impl_header_lifetime_elision,
329 impl_trait_in_bindings,
335 inclusive_range_syntax,
336 infer_outlives_requirements,
337 infer_static_outlives_requirements,
344 irrefutable_let_patterns,
347 issue_5723_bootstrap,
348 issue_tracker_base_url,
367 link_llvm_intrinsics,
376 macro_at_most_once_rep,
379 macro_lifetime_matcher,
380 macro_literal_matcher,
391 match_beginning_vert,
392 match_default_bindings,
402 movbe_target_feature,
436 omit_gdb_pretty_printer_section,
443 optin_builtin_traits,
451 overlapping_marker_traits,
456 panic_implementation,
475 poll_with_tls_context,
476 powerpc_target_feature,
477 precise_pointer_size_matching,
481 proc_dash_macro: "proc-macro",
483 proc_macro_attribute,
490 proc_macro_non_items,
491 proc_macro_path_invoc,
495 quad_precision_float,
508 reexport_test_harness_main,
518 re_rebalance_coherence,
532 rustc_allocator_nounwind,
533 rustc_allow_const_fn_ptr,
534 rustc_args_required_const,
537 rustc_const_unstable,
538 rustc_conversion_suggestion,
539 rustc_copy_clone_marker,
542 rustc_diagnostic_macros,
544 rustc_doc_only_macro,
546 rustc_dump_env_program_clauses,
547 rustc_dump_program_clauses,
548 rustc_dump_user_substs,
550 rustc_expected_cgu_reuse,
551 rustc_if_this_changed,
552 rustc_inherit_overflow_checks,
554 rustc_layout_scalar_valid_range_end,
555 rustc_layout_scalar_valid_range_start,
557 rustc_nonnull_optimization_guaranteed,
558 rustc_object_lifetime_default,
559 rustc_on_unimplemented,
562 rustc_partition_codegened,
563 rustc_partition_reused,
565 rustc_peek_definite_init,
566 rustc_peek_maybe_init,
567 rustc_peek_maybe_uninit,
569 rustc_proc_macro_decls,
573 rustc_std_internal_symbol,
577 rustc_then_this_would_need,
578 rustc_transparent_macro,
582 rust_eh_unwind_resume,
584 __rust_unstable_column,
585 rvalue_static_promotion,
602 sse4a_target_feature,
613 stmt_expr_attributes,
615 struct_field_attributes,
627 termination_trait_test,
630 test_accepted_feature,
632 test_removed_feature,
654 type_alias_enum_variants,
664 underscore_const_names,
666 underscore_lifetimes,
668 universal_impl_trait,
671 unrestricted_attribute_tokens,
672 unsafe_destructor_blind_to_params,
675 unsized_tuple_coercion,
690 visible_private_types,
693 warn_directory_ownership,
703 #[derive(Copy, Clone, Eq)]
711 /// Constructs a new identifier from a symbol and a span.
712 pub const fn new(name: Symbol, span: Span) -> Ident {
716 /// Constructs a new identifier with an empty syntax context.
718 pub const fn with_empty_ctxt(name: Symbol) -> Ident {
719 Ident::new(name, DUMMY_SP)
723 pub fn invalid() -> Ident {
724 Ident::with_empty_ctxt(kw::Invalid)
727 /// Maps an interned string to an identifier with an empty syntax context.
728 pub fn from_interned_str(string: InternedString) -> Ident {
729 Ident::with_empty_ctxt(string.as_symbol())
732 /// Maps a string to an identifier with an empty span.
733 pub fn from_str(string: &str) -> Ident {
734 Ident::with_empty_ctxt(Symbol::intern(string))
737 /// Maps a string and a span to an identifier.
738 pub fn from_str_and_span(string: &str, span: Span) -> Ident {
739 Ident::new(Symbol::intern(string), span)
742 /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
743 pub fn with_span_pos(self, span: Span) -> Ident {
744 Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
747 pub fn without_first_quote(self) -> Ident {
748 Ident::new(Symbol::intern(self.as_str().trim_start_matches('\'')), self.span)
751 /// "Normalize" ident for use in comparisons using "item hygiene".
752 /// Identifiers with same string value become same if they came from the same "modern" macro
753 /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
754 /// different "modern" macros.
755 /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
756 pub fn modern(self) -> Ident {
757 Ident::new(self.name, self.span.modern())
760 /// "Normalize" ident for use in comparisons using "local variable hygiene".
761 /// Identifiers with same string value become same if they came from the same non-transparent
762 /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
763 /// non-transparent macros.
764 /// Technically, this operation strips all transparent marks from ident's syntactic context.
765 pub fn modern_and_legacy(self) -> Ident {
766 Ident::new(self.name, self.span.modern_and_legacy())
769 /// Transforms an identifier into one with the same name, but gensymed.
770 pub fn gensym(self) -> Ident {
771 let name = with_interner(|interner| interner.gensymed(self.name));
772 Ident::new(name, self.span)
775 /// Transforms an underscore identifier into one with the same name, but
776 /// gensymed. Leaves non-underscore identifiers unchanged.
777 pub fn gensym_if_underscore(self) -> Ident {
778 if self.name == kw::Underscore { self.gensym() } else { self }
781 // WARNING: this function is deprecated and will be removed in the future.
782 pub fn is_gensymed(self) -> bool {
783 with_interner(|interner| interner.is_gensymed(self.name))
786 pub fn as_str(self) -> LocalInternedString {
790 pub fn as_interned_str(self) -> InternedString {
791 self.name.as_interned_str()
795 impl PartialEq for Ident {
796 fn eq(&self, rhs: &Self) -> bool {
797 self.name == rhs.name && self.span.ctxt() == rhs.span.ctxt()
801 impl Hash for Ident {
802 fn hash<H: Hasher>(&self, state: &mut H) {
803 self.name.hash(state);
804 self.span.ctxt().hash(state);
808 impl fmt::Debug for Ident {
809 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
810 write!(f, "{}{:?}", self.name, self.span.ctxt())
814 impl fmt::Display for Ident {
815 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
816 fmt::Display::fmt(&self.name, f)
820 impl Encodable for Ident {
821 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
822 if self.span.ctxt().modern() == SyntaxContext::empty() {
823 s.emit_str(&self.as_str())
824 } else { // FIXME(jseyfried): intercrate hygiene
825 let mut string = "#".to_owned();
826 string.push_str(&self.as_str());
832 impl Decodable for Ident {
833 fn decode<D: Decoder>(d: &mut D) -> Result<Ident, D::Error> {
834 let string = d.read_str()?;
835 Ok(if !string.starts_with('#') {
836 Ident::from_str(&string)
837 } else { // FIXME(jseyfried): intercrate hygiene
838 Ident::from_str(&string[1..]).gensym()
843 /// A symbol is an interned or gensymed string. A gensym is a symbol that is
844 /// never equal to any other symbol.
846 /// Conceptually, a gensym can be thought of as a normal symbol with an
847 /// invisible unique suffix. Gensyms are useful when creating new identifiers
848 /// that must not match any existing identifiers, e.g. during macro expansion
849 /// and syntax desugaring. Because gensyms should always be identifiers, all
850 /// gensym operations are on `Ident` rather than `Symbol`. (Indeed, in the
851 /// future the gensym-ness may be moved from `Symbol` to hygiene data.)
855 /// assert_eq!(Ident::from_str("x"), Ident::from_str("x"))
856 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x"))
857 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x").gensym())
859 /// Internally, a symbol is implemented as an index, and all operations
860 /// (including hashing, equality, and ordering) operate on that index. The use
861 /// of `newtype_index!` means that `Option<Symbol>` only takes up 4 bytes,
862 /// because `newtype_index!` reserves the last 256 values for tagging purposes.
864 /// Note that `Symbol` cannot directly be a `newtype_index!` because it
865 /// implements `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
866 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
867 pub struct Symbol(SymbolIndex);
870 pub struct SymbolIndex { .. }
874 const fn new(n: u32) -> Self {
875 Symbol(SymbolIndex::from_u32_const(n))
878 /// Maps a string to its interned representation.
879 pub fn intern(string: &str) -> Self {
880 with_interner(|interner| interner.intern(string))
883 pub fn as_str(self) -> LocalInternedString {
884 with_interner(|interner| unsafe {
885 LocalInternedString {
886 string: std::mem::transmute::<&str, &str>(interner.get(self))
891 pub fn as_interned_str(self) -> InternedString {
892 with_interner(|interner| InternedString {
893 symbol: interner.interned(self)
897 pub fn as_u32(self) -> u32 {
902 impl fmt::Debug for Symbol {
903 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
904 let is_gensymed = with_interner(|interner| interner.is_gensymed(*self));
906 write!(f, "{}({:?})", self, self.0)
908 write!(f, "{}", self)
913 impl fmt::Display for Symbol {
914 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
915 fmt::Display::fmt(&self.as_str(), f)
919 impl Encodable for Symbol {
920 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
921 s.emit_str(&self.as_str())
925 impl Decodable for Symbol {
926 fn decode<D: Decoder>(d: &mut D) -> Result<Symbol, D::Error> {
927 Ok(Symbol::intern(&d.read_str()?))
931 // The `&'static str`s in this type actually point into the arena.
933 // Note that normal symbols are indexed upward from 0, and gensyms are indexed
934 // downward from SymbolIndex::MAX_AS_U32.
936 pub struct Interner {
937 arena: DroplessArena,
938 names: FxHashMap<&'static str, Symbol>,
939 strings: Vec<&'static str>,
940 gensyms: Vec<Symbol>,
944 fn prefill(init: &[&'static str]) -> Self {
946 strings: init.into(),
947 names: init.iter().copied().zip((0..).map(Symbol::new)).collect(),
952 pub fn intern(&mut self, string: &str) -> Symbol {
953 if let Some(&name) = self.names.get(string) {
957 let name = Symbol::new(self.strings.len() as u32);
959 // `from_utf8_unchecked` is safe since we just allocated a `&str` which is known to be
961 let string: &str = unsafe {
962 str::from_utf8_unchecked(self.arena.alloc_slice(string.as_bytes()))
964 // It is safe to extend the arena allocation to `'static` because we only access
965 // these while the arena is still alive.
966 let string: &'static str = unsafe {
967 &*(string as *const str)
969 self.strings.push(string);
970 self.names.insert(string, name);
974 fn interned(&self, symbol: Symbol) -> Symbol {
975 if (symbol.0.as_usize()) < self.strings.len() {
978 self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize]
982 fn gensymed(&mut self, symbol: Symbol) -> Symbol {
983 self.gensyms.push(symbol);
984 Symbol::new(SymbolIndex::MAX_AS_U32 - self.gensyms.len() as u32 + 1)
987 fn is_gensymed(&mut self, symbol: Symbol) -> bool {
988 symbol.0.as_usize() >= self.strings.len()
991 // Get the symbol as a string. `Symbol::as_str()` should be used in
992 // preference to this function.
993 pub fn get(&self, symbol: Symbol) -> &str {
994 match self.strings.get(symbol.0.as_usize()) {
995 Some(string) => string,
997 let symbol = self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize];
998 self.strings[symbol.0.as_usize()]
1004 // This module has a very short name because it's used a lot.
1010 // This module has a very short name because it's used a lot.
1012 use std::convert::TryInto;
1017 // Get the symbol for an integer. The first few non-negative integers each
1018 // have a static symbol and therefore are fast.
1019 pub fn integer<N: TryInto<usize> + Copy + ToString>(n: N) -> Symbol {
1020 if let Result::Ok(idx) = n.try_into() {
1021 if let Option::Some(&sym) = digits_array.get(idx) {
1025 Symbol::intern(&n.to_string())
1030 fn is_used_keyword_2018(self) -> bool {
1034 fn is_unused_keyword_2018(self) -> bool {
1035 self >= kw::Async && self <= kw::Try
1038 /// Used for sanity checking rustdoc keyword sections.
1039 pub fn is_doc_keyword(self) -> bool {
1043 /// A keyword or reserved identifier that can be used as a path segment.
1044 pub fn is_path_segment_keyword(self) -> bool {
1045 self == kw::Super ||
1046 self == kw::SelfLower ||
1047 self == kw::SelfUpper ||
1048 self == kw::Crate ||
1049 self == kw::PathRoot ||
1050 self == kw::DollarCrate
1053 /// This symbol can be a raw identifier.
1054 pub fn can_be_raw(self) -> bool {
1055 self != kw::Invalid && self != kw::Underscore && !self.is_path_segment_keyword()
1060 // Returns `true` for reserved identifiers used internally for elided lifetimes,
1061 // unnamed method parameters, crate root module, error recovery etc.
1062 pub fn is_special(self) -> bool {
1063 self.name <= kw::Underscore
1066 /// Returns `true` if the token is a keyword used in the language.
1067 pub fn is_used_keyword(self) -> bool {
1068 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1069 self.name >= kw::As && self.name <= kw::While ||
1070 self.name.is_used_keyword_2018() && self.span.rust_2018()
1073 /// Returns `true` if the token is a keyword reserved for possible future use.
1074 pub fn is_unused_keyword(self) -> bool {
1075 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1076 self.name >= kw::Abstract && self.name <= kw::Yield ||
1077 self.name.is_unused_keyword_2018() && self.span.rust_2018()
1080 /// Returns `true` if the token is either a special identifier or a keyword.
1081 pub fn is_reserved(self) -> bool {
1082 self.is_special() || self.is_used_keyword() || self.is_unused_keyword()
1085 /// A keyword or reserved identifier that can be used as a path segment.
1086 pub fn is_path_segment_keyword(self) -> bool {
1087 self.name.is_path_segment_keyword()
1090 /// We see this identifier in a normal identifier position, like variable name or a type.
1091 /// How was it written originally? Did it use the raw form? Let's try to guess.
1092 pub fn is_raw_guess(self) -> bool {
1093 self.name.can_be_raw() && self.is_reserved()
1097 // If an interner exists, return it. Otherwise, prepare a fresh one.
1099 fn with_interner<T, F: FnOnce(&mut Interner) -> T>(f: F) -> T {
1100 GLOBALS.with(|globals| f(&mut *globals.symbol_interner.lock()))
1103 /// An alternative to `Symbol` and `InternedString`, useful when the chars
1104 /// within the symbol need to be accessed. It is best used for temporary
1107 /// Because the interner outlives any thread which uses this type, we can
1108 /// safely treat `string` which points to interner data, as an immortal string,
1109 /// as long as this type never crosses between threads.
1111 // FIXME: ensure that the interner outlives any thread which uses
1112 // `LocalInternedString`, by creating a new thread right after constructing the
1114 #[derive(Clone, Copy, Hash, PartialOrd, Eq, Ord)]
1115 pub struct LocalInternedString {
1116 string: &'static str,
1119 impl LocalInternedString {
1120 /// Maps a string to its interned representation.
1121 pub fn intern(string: &str) -> Self {
1122 let string = with_interner(|interner| {
1123 let symbol = interner.intern(string);
1124 interner.strings[symbol.0.as_usize()]
1126 LocalInternedString {
1127 string: unsafe { std::mem::transmute::<&str, &str>(string) }
1131 pub fn as_interned_str(self) -> InternedString {
1133 symbol: Symbol::intern(self.string)
1137 pub fn get(&self) -> &str {
1138 // This returns a valid string since we ensure that `self` outlives the interner
1139 // by creating the interner on a thread which outlives threads which can access it.
1140 // This type cannot move to a thread which outlives the interner since it does
1141 // not implement Send.
1146 impl<U: ?Sized> std::convert::AsRef<U> for LocalInternedString
1148 str: std::convert::AsRef<U>
1150 fn as_ref(&self) -> &U {
1151 self.string.as_ref()
1155 impl<T: std::ops::Deref<Target = str>> std::cmp::PartialEq<T> for LocalInternedString {
1156 fn eq(&self, other: &T) -> bool {
1157 self.string == other.deref()
1161 impl std::cmp::PartialEq<LocalInternedString> for str {
1162 fn eq(&self, other: &LocalInternedString) -> bool {
1163 self == other.string
1167 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a str {
1168 fn eq(&self, other: &LocalInternedString) -> bool {
1169 *self == other.string
1173 impl std::cmp::PartialEq<LocalInternedString> for String {
1174 fn eq(&self, other: &LocalInternedString) -> bool {
1175 self == other.string
1179 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a String {
1180 fn eq(&self, other: &LocalInternedString) -> bool {
1181 *self == other.string
1185 impl !Send for LocalInternedString {}
1186 impl !Sync for LocalInternedString {}
1188 impl std::ops::Deref for LocalInternedString {
1190 fn deref(&self) -> &str { self.string }
1193 impl fmt::Debug for LocalInternedString {
1194 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1195 fmt::Debug::fmt(self.string, f)
1199 impl fmt::Display for LocalInternedString {
1200 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1201 fmt::Display::fmt(self.string, f)
1205 impl Decodable for LocalInternedString {
1206 fn decode<D: Decoder>(d: &mut D) -> Result<LocalInternedString, D::Error> {
1207 Ok(LocalInternedString::intern(&d.read_str()?))
1211 impl Encodable for LocalInternedString {
1212 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1213 s.emit_str(self.string)
1217 /// An alternative to `Symbol` that is focused on string contents. It has two
1218 /// main differences to `Symbol`.
1220 /// First, its implementations of `Hash`, `PartialOrd` and `Ord` work with the
1221 /// string chars rather than the symbol integer. This is useful when hash
1222 /// stability is required across compile sessions, or a guaranteed sort
1223 /// ordering is required.
1225 /// Second, gensym-ness is irrelevant. E.g.:
1227 /// assert_ne!(Symbol::gensym("x"), Symbol::gensym("x"))
1228 /// assert_eq!(Symbol::gensym("x").as_interned_str(), Symbol::gensym("x").as_interned_str())
1230 #[derive(Clone, Copy, PartialEq, Eq)]
1231 pub struct InternedString {
1235 impl InternedString {
1236 /// Maps a string to its interned representation.
1237 pub fn intern(string: &str) -> Self {
1239 symbol: Symbol::intern(string)
1243 pub fn with<F: FnOnce(&str) -> R, R>(self, f: F) -> R {
1244 let str = with_interner(|interner| {
1245 interner.get(self.symbol) as *const str
1247 // This is safe because the interner keeps string alive until it is dropped.
1248 // We can access it because we know the interner is still alive since we use a
1249 // scoped thread local to access it, and it was alive at the beginning of this scope
1253 fn with2<F: FnOnce(&str, &str) -> R, R>(self, other: &InternedString, f: F) -> R {
1254 let (self_str, other_str) = with_interner(|interner| {
1255 (interner.get(self.symbol) as *const str,
1256 interner.get(other.symbol) as *const str)
1258 // This is safe for the same reason that `with` is safe.
1259 unsafe { f(&*self_str, &*other_str) }
1262 pub fn as_symbol(self) -> Symbol {
1266 pub fn as_str(self) -> LocalInternedString {
1267 self.symbol.as_str()
1271 impl Hash for InternedString {
1272 fn hash<H: Hasher>(&self, state: &mut H) {
1273 self.with(|str| str.hash(state))
1277 impl PartialOrd<InternedString> for InternedString {
1278 fn partial_cmp(&self, other: &InternedString) -> Option<Ordering> {
1279 if self.symbol == other.symbol {
1280 return Some(Ordering::Equal);
1282 self.with2(other, |self_str, other_str| self_str.partial_cmp(other_str))
1286 impl Ord for InternedString {
1287 fn cmp(&self, other: &InternedString) -> Ordering {
1288 if self.symbol == other.symbol {
1289 return Ordering::Equal;
1291 self.with2(other, |self_str, other_str| self_str.cmp(other_str))
1295 impl fmt::Debug for InternedString {
1296 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1297 self.with(|str| fmt::Debug::fmt(&str, f))
1301 impl fmt::Display for InternedString {
1302 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1303 self.with(|str| fmt::Display::fmt(&str, f))
1307 impl Decodable for InternedString {
1308 fn decode<D: Decoder>(d: &mut D) -> Result<InternedString, D::Error> {
1309 Ok(InternedString::intern(&d.read_str()?))
1313 impl Encodable for InternedString {
1314 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1315 self.with(|string| s.emit_str(string))
1326 fn interner_tests() {
1327 let mut i: Interner = Interner::default();
1328 // first one is zero:
1329 assert_eq!(i.intern("dog"), Symbol::new(0));
1330 // re-use gets the same entry:
1331 assert_eq!(i.intern("dog"), Symbol::new(0));
1332 // different string gets a different #:
1333 assert_eq!(i.intern("cat"), Symbol::new(1));
1334 assert_eq!(i.intern("cat"), Symbol::new(1));
1335 // dog is still at zero
1336 assert_eq!(i.intern("dog"), Symbol::new(0));
1337 let z = i.intern("zebra");
1338 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32));
1339 // gensym of same string gets new number:
1340 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32 - 1));
1341 // gensym of *existing* string gets new number:
1342 let d = i.intern("dog");
1343 assert_eq!(i.gensymed(d), Symbol::new(SymbolIndex::MAX_AS_U32 - 2));
1347 fn without_first_quote_test() {
1348 GLOBALS.set(&Globals::new(edition::DEFAULT_EDITION), || {
1349 let i = Ident::from_str("'break");
1350 assert_eq!(i.without_first_quote().name, kw::Break);