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_enum_discriminant,
139 arbitrary_self_types,
145 associated_type_bounds,
146 associated_type_defaults,
153 augmented_assignments,
154 automatically_derived,
155 avx512_target_feature,
160 bind_by_move_pattern_guards,
163 borrowck_graphviz_postflow,
164 borrowck_graphviz_preflow,
167 braced_empty_structs,
174 cfg_target_has_atomic,
175 cfg_target_thread_local,
183 closure_to_fn_coercion,
185 cmpxchg16b_target_feature,
190 conservative_impl_trait,
192 const_compare_raw_pointers,
201 const_raw_ptr_to_usize_cast,
214 crate_visibility_modifier,
217 custom_inner_attributes,
218 custom_test_frameworks,
223 default_lib_allocator,
224 default_type_parameter_fallback,
238 document_private_items,
239 dotdoteq_in_patterns,
240 dotdot_in_tuple_patterns,
241 double_braced_crate: "{{crate}}",
242 double_braced_impl: "{{impl}}",
243 double_braced_misc: "{{misc}}",
244 double_braced_closure: "{{closure}}",
245 double_braced_constructor: "{{constructor}}",
246 double_braced_constant: "{{constant}}",
247 double_braced_opaque: "{{opaque}}",
249 dropck_parametricity,
261 exclusive_range_pattern,
262 exhaustive_integer_patterns,
268 extern_absolute_paths,
270 extern_crate_item_prelude,
281 field_init_shorthand,
303 generic_associated_types,
312 hexagon_target_feature,
314 homogeneous_aggregate,
328 if_while_or_patterns,
330 impl_header_lifetime_elision,
332 impl_trait_in_bindings,
338 inclusive_range_syntax,
339 infer_outlives_requirements,
340 infer_static_outlives_requirements,
347 irrefutable_let_patterns,
350 issue_5723_bootstrap,
351 issue_tracker_base_url,
370 link_llvm_intrinsics,
379 macro_at_most_once_rep,
382 macro_lifetime_matcher,
383 macro_literal_matcher,
394 match_beginning_vert,
395 match_default_bindings,
406 movbe_target_feature,
440 omit_gdb_pretty_printer_section,
447 optin_builtin_traits,
455 overlapping_marker_traits,
460 panic_implementation,
479 poll_with_tls_context,
480 powerpc_target_feature,
481 precise_pointer_size_matching,
485 proc_dash_macro: "proc-macro",
487 proc_macro_attribute,
494 proc_macro_non_items,
495 proc_macro_path_invoc,
499 quad_precision_float,
512 reexport_test_harness_main,
522 re_rebalance_coherence,
536 rustc_allocator_nounwind,
537 rustc_allow_const_fn_ptr,
538 rustc_args_required_const,
542 rustc_const_unstable,
543 rustc_conversion_suggestion,
544 rustc_copy_clone_marker,
547 rustc_diagnostic_macros,
550 rustc_dump_env_program_clauses,
551 rustc_dump_program_clauses,
552 rustc_dump_user_substs,
554 rustc_expected_cgu_reuse,
555 rustc_if_this_changed,
556 rustc_inherit_overflow_checks,
558 rustc_layout_scalar_valid_range_end,
559 rustc_layout_scalar_valid_range_start,
561 rustc_nonnull_optimization_guaranteed,
562 rustc_object_lifetime_default,
563 rustc_on_unimplemented,
566 rustc_partition_codegened,
567 rustc_partition_reused,
569 rustc_peek_definite_init,
570 rustc_peek_maybe_init,
571 rustc_peek_maybe_uninit,
573 rustc_proc_macro_decls,
577 rustc_std_internal_symbol,
581 rustc_then_this_would_need,
582 rustc_transparent_macro,
586 rust_eh_unwind_resume,
588 __rust_unstable_column,
589 rvalue_static_promotion,
606 sse4a_target_feature,
617 stmt_expr_attributes,
619 struct_field_attributes,
631 termination_trait_test,
634 test_accepted_feature,
636 test_removed_feature,
658 type_alias_enum_variants,
668 underscore_const_names,
670 underscore_lifetimes,
672 universal_impl_trait,
675 unrestricted_attribute_tokens,
676 unsafe_destructor_blind_to_params,
679 unsized_tuple_coercion,
694 visible_private_types,
697 warn_directory_ownership,
707 #[derive(Copy, Clone, Eq)]
715 /// Constructs a new identifier from a symbol and a span.
716 pub const fn new(name: Symbol, span: Span) -> Ident {
720 /// Constructs a new identifier with an empty syntax context.
722 pub const fn with_empty_ctxt(name: Symbol) -> Ident {
723 Ident::new(name, DUMMY_SP)
727 pub fn invalid() -> Ident {
728 Ident::with_empty_ctxt(kw::Invalid)
731 /// Maps an interned string to an identifier with an empty syntax context.
732 pub fn from_interned_str(string: InternedString) -> Ident {
733 Ident::with_empty_ctxt(string.as_symbol())
736 /// Maps a string to an identifier with an empty span.
737 pub fn from_str(string: &str) -> Ident {
738 Ident::with_empty_ctxt(Symbol::intern(string))
741 /// Maps a string and a span to an identifier.
742 pub fn from_str_and_span(string: &str, span: Span) -> Ident {
743 Ident::new(Symbol::intern(string), span)
746 /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
747 pub fn with_span_pos(self, span: Span) -> Ident {
748 Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
751 pub fn without_first_quote(self) -> Ident {
752 Ident::new(Symbol::intern(self.as_str().trim_start_matches('\'')), self.span)
755 /// "Normalize" ident for use in comparisons using "item hygiene".
756 /// Identifiers with same string value become same if they came from the same "modern" macro
757 /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
758 /// different "modern" macros.
759 /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
760 pub fn modern(self) -> Ident {
761 Ident::new(self.name, self.span.modern())
764 /// "Normalize" ident for use in comparisons using "local variable hygiene".
765 /// Identifiers with same string value become same if they came from the same non-transparent
766 /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
767 /// non-transparent macros.
768 /// Technically, this operation strips all transparent marks from ident's syntactic context.
769 pub fn modern_and_legacy(self) -> Ident {
770 Ident::new(self.name, self.span.modern_and_legacy())
773 /// Transforms an identifier into one with the same name, but gensymed.
774 pub fn gensym(self) -> Ident {
775 let name = with_interner(|interner| interner.gensymed(self.name));
776 Ident::new(name, self.span)
779 /// Transforms an underscore identifier into one with the same name, but
780 /// gensymed. Leaves non-underscore identifiers unchanged.
781 pub fn gensym_if_underscore(self) -> Ident {
782 if self.name == kw::Underscore { self.gensym() } else { self }
785 // WARNING: this function is deprecated and will be removed in the future.
786 pub fn is_gensymed(self) -> bool {
787 with_interner(|interner| interner.is_gensymed(self.name))
790 pub fn as_str(self) -> LocalInternedString {
794 pub fn as_interned_str(self) -> InternedString {
795 self.name.as_interned_str()
799 impl PartialEq for Ident {
800 fn eq(&self, rhs: &Self) -> bool {
801 self.name == rhs.name && self.span.ctxt() == rhs.span.ctxt()
805 impl Hash for Ident {
806 fn hash<H: Hasher>(&self, state: &mut H) {
807 self.name.hash(state);
808 self.span.ctxt().hash(state);
812 impl fmt::Debug for Ident {
813 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
814 write!(f, "{}{:?}", self.name, self.span.ctxt())
818 impl fmt::Display for Ident {
819 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
820 fmt::Display::fmt(&self.name, f)
824 impl Encodable for Ident {
825 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
826 if self.span.ctxt().modern() == SyntaxContext::empty() {
827 s.emit_str(&self.as_str())
828 } else { // FIXME(jseyfried): intercrate hygiene
829 let mut string = "#".to_owned();
830 string.push_str(&self.as_str());
836 impl Decodable for Ident {
837 fn decode<D: Decoder>(d: &mut D) -> Result<Ident, D::Error> {
838 let string = d.read_str()?;
839 Ok(if !string.starts_with('#') {
840 Ident::from_str(&string)
841 } else { // FIXME(jseyfried): intercrate hygiene
842 Ident::from_str(&string[1..]).gensym()
847 /// A symbol is an interned or gensymed string. A gensym is a symbol that is
848 /// never equal to any other symbol.
850 /// Conceptually, a gensym can be thought of as a normal symbol with an
851 /// invisible unique suffix. Gensyms are useful when creating new identifiers
852 /// that must not match any existing identifiers, e.g. during macro expansion
853 /// and syntax desugaring. Because gensyms should always be identifiers, all
854 /// gensym operations are on `Ident` rather than `Symbol`. (Indeed, in the
855 /// future the gensym-ness may be moved from `Symbol` to hygiene data.)
859 /// assert_eq!(Ident::from_str("x"), Ident::from_str("x"))
860 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x"))
861 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x").gensym())
863 /// Internally, a symbol is implemented as an index, and all operations
864 /// (including hashing, equality, and ordering) operate on that index. The use
865 /// of `newtype_index!` means that `Option<Symbol>` only takes up 4 bytes,
866 /// because `newtype_index!` reserves the last 256 values for tagging purposes.
868 /// Note that `Symbol` cannot directly be a `newtype_index!` because it
869 /// implements `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
870 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
871 pub struct Symbol(SymbolIndex);
874 pub struct SymbolIndex { .. }
878 const fn new(n: u32) -> Self {
879 Symbol(SymbolIndex::from_u32_const(n))
882 /// Maps a string to its interned representation.
883 pub fn intern(string: &str) -> Self {
884 with_interner(|interner| interner.intern(string))
887 pub fn as_str(self) -> LocalInternedString {
888 with_interner(|interner| unsafe {
889 LocalInternedString {
890 string: std::mem::transmute::<&str, &str>(interner.get(self))
895 pub fn as_interned_str(self) -> InternedString {
896 with_interner(|interner| InternedString {
897 symbol: interner.interned(self)
901 pub fn as_u32(self) -> u32 {
906 impl fmt::Debug for Symbol {
907 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
908 let is_gensymed = with_interner(|interner| interner.is_gensymed(*self));
910 write!(f, "{}({:?})", self, self.0)
912 write!(f, "{}", self)
917 impl fmt::Display for Symbol {
918 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
919 fmt::Display::fmt(&self.as_str(), f)
923 impl Encodable for Symbol {
924 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
925 s.emit_str(&self.as_str())
929 impl Decodable for Symbol {
930 fn decode<D: Decoder>(d: &mut D) -> Result<Symbol, D::Error> {
931 Ok(Symbol::intern(&d.read_str()?))
935 // The `&'static str`s in this type actually point into the arena.
937 // Note that normal symbols are indexed upward from 0, and gensyms are indexed
938 // downward from SymbolIndex::MAX_AS_U32.
940 pub struct Interner {
941 arena: DroplessArena,
942 names: FxHashMap<&'static str, Symbol>,
943 strings: Vec<&'static str>,
944 gensyms: Vec<Symbol>,
948 fn prefill(init: &[&'static str]) -> Self {
950 strings: init.into(),
951 names: init.iter().copied().zip((0..).map(Symbol::new)).collect(),
956 pub fn intern(&mut self, string: &str) -> Symbol {
957 if let Some(&name) = self.names.get(string) {
961 let name = Symbol::new(self.strings.len() as u32);
963 // `from_utf8_unchecked` is safe since we just allocated a `&str` which is known to be
965 let string: &str = unsafe {
966 str::from_utf8_unchecked(self.arena.alloc_slice(string.as_bytes()))
968 // It is safe to extend the arena allocation to `'static` because we only access
969 // these while the arena is still alive.
970 let string: &'static str = unsafe {
971 &*(string as *const str)
973 self.strings.push(string);
974 self.names.insert(string, name);
978 fn interned(&self, symbol: Symbol) -> Symbol {
979 if (symbol.0.as_usize()) < self.strings.len() {
982 self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize]
986 fn gensymed(&mut self, symbol: Symbol) -> Symbol {
987 self.gensyms.push(symbol);
988 Symbol::new(SymbolIndex::MAX_AS_U32 - self.gensyms.len() as u32 + 1)
991 fn is_gensymed(&mut self, symbol: Symbol) -> bool {
992 symbol.0.as_usize() >= self.strings.len()
995 // Get the symbol as a string. `Symbol::as_str()` should be used in
996 // preference to this function.
997 pub fn get(&self, symbol: Symbol) -> &str {
998 match self.strings.get(symbol.0.as_usize()) {
999 Some(string) => string,
1001 let symbol = self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize];
1002 self.strings[symbol.0.as_usize()]
1008 // This module has a very short name because it's used a lot.
1014 // This module has a very short name because it's used a lot.
1016 use std::convert::TryInto;
1021 // Get the symbol for an integer. The first few non-negative integers each
1022 // have a static symbol and therefore are fast.
1023 pub fn integer<N: TryInto<usize> + Copy + ToString>(n: N) -> Symbol {
1024 if let Result::Ok(idx) = n.try_into() {
1025 if let Option::Some(&sym) = digits_array.get(idx) {
1029 Symbol::intern(&n.to_string())
1034 fn is_used_keyword_2018(self) -> bool {
1038 fn is_unused_keyword_2018(self) -> bool {
1039 self >= kw::Async && self <= kw::Try
1042 /// Used for sanity checking rustdoc keyword sections.
1043 pub fn is_doc_keyword(self) -> bool {
1047 /// A keyword or reserved identifier that can be used as a path segment.
1048 pub fn is_path_segment_keyword(self) -> bool {
1049 self == kw::Super ||
1050 self == kw::SelfLower ||
1051 self == kw::SelfUpper ||
1052 self == kw::Crate ||
1053 self == kw::PathRoot ||
1054 self == kw::DollarCrate
1057 /// This symbol can be a raw identifier.
1058 pub fn can_be_raw(self) -> bool {
1059 self != kw::Invalid && self != kw::Underscore && !self.is_path_segment_keyword()
1064 // Returns `true` for reserved identifiers used internally for elided lifetimes,
1065 // unnamed method parameters, crate root module, error recovery etc.
1066 pub fn is_special(self) -> bool {
1067 self.name <= kw::Underscore
1070 /// Returns `true` if the token is a keyword used in the language.
1071 pub fn is_used_keyword(self) -> bool {
1072 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1073 self.name >= kw::As && self.name <= kw::While ||
1074 self.name.is_used_keyword_2018() && self.span.rust_2018()
1077 /// Returns `true` if the token is a keyword reserved for possible future use.
1078 pub fn is_unused_keyword(self) -> bool {
1079 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1080 self.name >= kw::Abstract && self.name <= kw::Yield ||
1081 self.name.is_unused_keyword_2018() && self.span.rust_2018()
1084 /// Returns `true` if the token is either a special identifier or a keyword.
1085 pub fn is_reserved(self) -> bool {
1086 self.is_special() || self.is_used_keyword() || self.is_unused_keyword()
1089 /// A keyword or reserved identifier that can be used as a path segment.
1090 pub fn is_path_segment_keyword(self) -> bool {
1091 self.name.is_path_segment_keyword()
1094 /// We see this identifier in a normal identifier position, like variable name or a type.
1095 /// How was it written originally? Did it use the raw form? Let's try to guess.
1096 pub fn is_raw_guess(self) -> bool {
1097 self.name.can_be_raw() && self.is_reserved()
1101 // If an interner exists, return it. Otherwise, prepare a fresh one.
1103 fn with_interner<T, F: FnOnce(&mut Interner) -> T>(f: F) -> T {
1104 GLOBALS.with(|globals| f(&mut *globals.symbol_interner.lock()))
1107 /// An alternative to `Symbol` and `InternedString`, useful when the chars
1108 /// within the symbol need to be accessed. It is best used for temporary
1111 /// Because the interner outlives any thread which uses this type, we can
1112 /// safely treat `string` which points to interner data, as an immortal string,
1113 /// as long as this type never crosses between threads.
1115 // FIXME: ensure that the interner outlives any thread which uses
1116 // `LocalInternedString`, by creating a new thread right after constructing the
1118 #[derive(Clone, Copy, Hash, PartialOrd, Eq, Ord)]
1119 pub struct LocalInternedString {
1120 string: &'static str,
1123 impl LocalInternedString {
1124 /// Maps a string to its interned representation.
1125 pub fn intern(string: &str) -> Self {
1126 let string = with_interner(|interner| {
1127 let symbol = interner.intern(string);
1128 interner.strings[symbol.0.as_usize()]
1130 LocalInternedString {
1131 string: unsafe { std::mem::transmute::<&str, &str>(string) }
1135 pub fn as_interned_str(self) -> InternedString {
1137 symbol: Symbol::intern(self.string)
1142 pub fn get(&self) -> &str {
1143 // This returns a valid string since we ensure that `self` outlives the interner
1144 // by creating the interner on a thread which outlives threads which can access it.
1145 // This type cannot move to a thread which outlives the interner since it does
1146 // not implement Send.
1151 impl<U: ?Sized> std::convert::AsRef<U> for LocalInternedString
1153 str: std::convert::AsRef<U>
1156 fn as_ref(&self) -> &U {
1157 self.string.as_ref()
1161 impl<T: std::ops::Deref<Target = str>> std::cmp::PartialEq<T> for LocalInternedString {
1162 fn eq(&self, other: &T) -> bool {
1163 self.string == other.deref()
1167 impl std::cmp::PartialEq<LocalInternedString> for str {
1168 fn eq(&self, other: &LocalInternedString) -> bool {
1169 self == other.string
1173 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a str {
1174 fn eq(&self, other: &LocalInternedString) -> bool {
1175 *self == other.string
1179 impl std::cmp::PartialEq<LocalInternedString> for String {
1180 fn eq(&self, other: &LocalInternedString) -> bool {
1181 self == other.string
1185 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a String {
1186 fn eq(&self, other: &LocalInternedString) -> bool {
1187 *self == other.string
1191 impl !Send for LocalInternedString {}
1192 impl !Sync for LocalInternedString {}
1194 impl std::ops::Deref for LocalInternedString {
1197 fn deref(&self) -> &str { self.string }
1200 impl fmt::Debug for LocalInternedString {
1201 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1202 fmt::Debug::fmt(self.string, f)
1206 impl fmt::Display for LocalInternedString {
1207 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1208 fmt::Display::fmt(self.string, f)
1212 impl Decodable for LocalInternedString {
1213 fn decode<D: Decoder>(d: &mut D) -> Result<LocalInternedString, D::Error> {
1214 Ok(LocalInternedString::intern(&d.read_str()?))
1218 impl Encodable for LocalInternedString {
1219 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1220 s.emit_str(self.string)
1224 /// An alternative to `Symbol` that is focused on string contents. It has two
1225 /// main differences to `Symbol`.
1227 /// First, its implementations of `Hash`, `PartialOrd` and `Ord` work with the
1228 /// string chars rather than the symbol integer. This is useful when hash
1229 /// stability is required across compile sessions, or a guaranteed sort
1230 /// ordering is required.
1232 /// Second, gensym-ness is irrelevant. E.g.:
1234 /// assert_ne!(Symbol::gensym("x"), Symbol::gensym("x"))
1235 /// assert_eq!(Symbol::gensym("x").as_interned_str(), Symbol::gensym("x").as_interned_str())
1237 #[derive(Clone, Copy, PartialEq, Eq)]
1238 pub struct InternedString {
1242 impl InternedString {
1243 /// Maps a string to its interned representation.
1244 pub fn intern(string: &str) -> Self {
1246 symbol: Symbol::intern(string)
1250 pub fn with<F: FnOnce(&str) -> R, R>(self, f: F) -> R {
1251 let str = with_interner(|interner| {
1252 interner.get(self.symbol) as *const str
1254 // This is safe because the interner keeps string alive until it is dropped.
1255 // We can access it because we know the interner is still alive since we use a
1256 // scoped thread local to access it, and it was alive at the beginning of this scope
1260 fn with2<F: FnOnce(&str, &str) -> R, R>(self, other: &InternedString, f: F) -> R {
1261 let (self_str, other_str) = with_interner(|interner| {
1262 (interner.get(self.symbol) as *const str,
1263 interner.get(other.symbol) as *const str)
1265 // This is safe for the same reason that `with` is safe.
1266 unsafe { f(&*self_str, &*other_str) }
1269 pub fn as_symbol(self) -> Symbol {
1273 pub fn as_str(self) -> LocalInternedString {
1274 self.symbol.as_str()
1278 impl Hash for InternedString {
1279 fn hash<H: Hasher>(&self, state: &mut H) {
1280 self.with(|str| str.hash(state))
1284 impl PartialOrd<InternedString> for InternedString {
1285 fn partial_cmp(&self, other: &InternedString) -> Option<Ordering> {
1286 if self.symbol == other.symbol {
1287 return Some(Ordering::Equal);
1289 self.with2(other, |self_str, other_str| self_str.partial_cmp(other_str))
1293 impl Ord for InternedString {
1294 fn cmp(&self, other: &InternedString) -> Ordering {
1295 if self.symbol == other.symbol {
1296 return Ordering::Equal;
1298 self.with2(other, |self_str, other_str| self_str.cmp(other_str))
1302 impl fmt::Debug for InternedString {
1303 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1304 self.with(|str| fmt::Debug::fmt(&str, f))
1308 impl fmt::Display for InternedString {
1309 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1310 self.with(|str| fmt::Display::fmt(&str, f))
1314 impl Decodable for InternedString {
1315 fn decode<D: Decoder>(d: &mut D) -> Result<InternedString, D::Error> {
1316 Ok(InternedString::intern(&d.read_str()?))
1320 impl Encodable for InternedString {
1321 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1322 self.with(|string| s.emit_str(string))
1333 fn interner_tests() {
1334 let mut i: Interner = Interner::default();
1335 // first one is zero:
1336 assert_eq!(i.intern("dog"), Symbol::new(0));
1337 // re-use gets the same entry:
1338 assert_eq!(i.intern("dog"), Symbol::new(0));
1339 // different string gets a different #:
1340 assert_eq!(i.intern("cat"), Symbol::new(1));
1341 assert_eq!(i.intern("cat"), Symbol::new(1));
1342 // dog is still at zero
1343 assert_eq!(i.intern("dog"), Symbol::new(0));
1344 let z = i.intern("zebra");
1345 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32));
1346 // gensym of same string gets new number:
1347 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32 - 1));
1348 // gensym of *existing* string gets new number:
1349 let d = i.intern("dog");
1350 assert_eq!(i.gensymed(d), Symbol::new(SymbolIndex::MAX_AS_U32 - 2));
1354 fn without_first_quote_test() {
1355 GLOBALS.set(&Globals::new(edition::DEFAULT_EDITION), || {
1356 let i = Ident::from_str("'break");
1357 assert_eq!(i.without_first_quote().name, kw::Break);