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,
146 associated_type_bounds,
147 associated_type_defaults,
154 augmented_assignments,
155 automatically_derived,
156 avx512_target_feature,
161 bind_by_move_pattern_guards,
164 borrowck_graphviz_postflow,
165 borrowck_graphviz_preflow,
168 braced_empty_structs,
175 cfg_target_has_atomic,
176 cfg_target_thread_local,
184 closure_to_fn_coercion,
186 cmpxchg16b_target_feature,
193 conservative_impl_trait,
195 const_compare_raw_pointers,
204 const_raw_ptr_to_usize_cast,
218 crate_visibility_modifier,
221 custom_inner_attributes,
222 custom_test_frameworks,
229 default_lib_allocator,
230 default_type_parameter_fallback,
244 document_private_items,
245 dotdoteq_in_patterns,
246 dotdot_in_tuple_patterns,
247 double_braced_crate: "{{crate}}",
248 double_braced_impl: "{{impl}}",
249 double_braced_misc: "{{misc}}",
250 double_braced_closure: "{{closure}}",
251 double_braced_constructor: "{{constructor}}",
252 double_braced_constant: "{{constant}}",
253 double_braced_opaque: "{{opaque}}",
255 dropck_parametricity,
270 exclusive_range_pattern,
271 exhaustive_integer_patterns,
277 extern_absolute_paths,
279 extern_crate_item_prelude,
290 field_init_shorthand,
313 generic_associated_types,
322 hexagon_target_feature,
324 homogeneous_aggregate,
338 if_while_or_patterns,
340 impl_header_lifetime_elision,
342 impl_trait_in_bindings,
350 inclusive_range_syntax,
351 infer_outlives_requirements,
352 infer_static_outlives_requirements,
359 irrefutable_let_patterns,
362 issue_5723_bootstrap,
363 issue_tracker_base_url,
383 link_llvm_intrinsics,
392 macro_at_most_once_rep,
395 macro_lifetime_matcher,
396 macro_literal_matcher,
407 match_beginning_vert,
408 match_default_bindings,
420 movbe_target_feature,
454 omit_gdb_pretty_printer_section,
461 optin_builtin_traits,
470 overlapping_marker_traits,
475 panic_implementation,
495 poll_with_tls_context,
496 powerpc_target_feature,
497 precise_pointer_size_matching,
501 proc_dash_macro: "proc-macro",
503 proc_macro_attribute,
510 proc_macro_non_items,
511 proc_macro_path_invoc,
515 quad_precision_float,
528 reexport_test_harness_main,
538 re_rebalance_coherence,
554 rustc_allocator_nounwind,
555 rustc_allow_const_fn_ptr,
556 rustc_args_required_const,
560 rustc_const_unstable,
561 rustc_conversion_suggestion,
562 rustc_copy_clone_marker,
565 rustc_diagnostic_macros,
568 rustc_dump_env_program_clauses,
569 rustc_dump_program_clauses,
570 rustc_dump_user_substs,
572 rustc_expected_cgu_reuse,
573 rustc_if_this_changed,
574 rustc_inherit_overflow_checks,
576 rustc_layout_scalar_valid_range_end,
577 rustc_layout_scalar_valid_range_start,
578 rustc_macro_transparency,
580 rustc_nonnull_optimization_guaranteed,
581 rustc_object_lifetime_default,
582 rustc_on_unimplemented,
585 rustc_partition_codegened,
586 rustc_partition_reused,
588 rustc_peek_definite_init,
589 rustc_peek_maybe_init,
590 rustc_peek_maybe_uninit,
592 rustc_proc_macro_decls,
596 rustc_std_internal_symbol,
600 rustc_then_this_would_need,
604 rust_eh_unwind_resume,
606 __rust_unstable_column,
607 rvalue_static_promotion,
623 sse4a_target_feature,
635 stmt_expr_attributes,
637 struct_field_attributes,
649 termination_trait_test,
652 test_accepted_feature,
654 test_removed_feature,
676 type_alias_enum_variants,
686 underscore_const_names,
688 underscore_lifetimes,
690 universal_impl_trait,
693 unrestricted_attribute_tokens,
694 unsafe_destructor_blind_to_params,
697 unsized_tuple_coercion,
712 visible_private_types,
715 warn_directory_ownership,
725 #[derive(Copy, Clone, Eq)]
733 /// Constructs a new identifier from a symbol and a span.
734 pub const fn new(name: Symbol, span: Span) -> Ident {
738 /// Constructs a new identifier with an empty syntax context.
740 pub const fn with_empty_ctxt(name: Symbol) -> Ident {
741 Ident::new(name, DUMMY_SP)
745 pub fn invalid() -> Ident {
746 Ident::with_empty_ctxt(kw::Invalid)
749 /// Maps an interned string to an identifier with an empty syntax context.
750 pub fn from_interned_str(string: InternedString) -> Ident {
751 Ident::with_empty_ctxt(string.as_symbol())
754 /// Maps a string to an identifier with an empty span.
755 pub fn from_str(string: &str) -> Ident {
756 Ident::with_empty_ctxt(Symbol::intern(string))
759 /// Maps a string and a span to an identifier.
760 pub fn from_str_and_span(string: &str, span: Span) -> Ident {
761 Ident::new(Symbol::intern(string), span)
764 /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
765 pub fn with_span_pos(self, span: Span) -> Ident {
766 Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
769 pub fn without_first_quote(self) -> Ident {
770 Ident::new(Symbol::intern(self.as_str().trim_start_matches('\'')), self.span)
773 /// "Normalize" ident for use in comparisons using "item hygiene".
774 /// Identifiers with same string value become same if they came from the same "modern" macro
775 /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
776 /// different "modern" macros.
777 /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
778 pub fn modern(self) -> Ident {
779 Ident::new(self.name, self.span.modern())
782 /// "Normalize" ident for use in comparisons using "local variable hygiene".
783 /// Identifiers with same string value become same if they came from the same non-transparent
784 /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
785 /// non-transparent macros.
786 /// Technically, this operation strips all transparent marks from ident's syntactic context.
787 pub fn modern_and_legacy(self) -> Ident {
788 Ident::new(self.name, self.span.modern_and_legacy())
791 /// Transforms an identifier into one with the same name, but gensymed.
792 pub fn gensym(self) -> Ident {
793 let name = with_interner(|interner| interner.gensymed(self.name));
794 Ident::new(name, self.span)
797 /// Transforms an underscore identifier into one with the same name, but
798 /// gensymed. Leaves non-underscore identifiers unchanged.
799 pub fn gensym_if_underscore(self) -> Ident {
800 if self.name == kw::Underscore { self.gensym() } else { self }
803 // WARNING: this function is deprecated and will be removed in the future.
804 pub fn is_gensymed(self) -> bool {
805 with_interner(|interner| interner.is_gensymed(self.name))
808 pub fn as_str(self) -> LocalInternedString {
812 pub fn as_interned_str(self) -> InternedString {
813 self.name.as_interned_str()
817 impl PartialEq for Ident {
818 fn eq(&self, rhs: &Self) -> bool {
819 self.name == rhs.name && self.span.ctxt() == rhs.span.ctxt()
823 impl Hash for Ident {
824 fn hash<H: Hasher>(&self, state: &mut H) {
825 self.name.hash(state);
826 self.span.ctxt().hash(state);
830 impl fmt::Debug for Ident {
831 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
832 write!(f, "{}{:?}", self.name, self.span.ctxt())
836 impl fmt::Display for Ident {
837 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
838 fmt::Display::fmt(&self.name, f)
842 impl Encodable for Ident {
843 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
844 if self.span.ctxt().modern() == SyntaxContext::empty() {
845 s.emit_str(&self.as_str())
846 } else { // FIXME(jseyfried): intercrate hygiene
847 let mut string = "#".to_owned();
848 string.push_str(&self.as_str());
854 impl Decodable for Ident {
855 fn decode<D: Decoder>(d: &mut D) -> Result<Ident, D::Error> {
856 let string = d.read_str()?;
857 Ok(if !string.starts_with('#') {
858 Ident::from_str(&string)
859 } else { // FIXME(jseyfried): intercrate hygiene
860 Ident::from_str(&string[1..]).gensym()
865 /// A symbol is an interned or gensymed string. A gensym is a symbol that is
866 /// never equal to any other symbol.
868 /// Conceptually, a gensym can be thought of as a normal symbol with an
869 /// invisible unique suffix. Gensyms are useful when creating new identifiers
870 /// that must not match any existing identifiers, e.g. during macro expansion
871 /// and syntax desugaring. Because gensyms should always be identifiers, all
872 /// gensym operations are on `Ident` rather than `Symbol`. (Indeed, in the
873 /// future the gensym-ness may be moved from `Symbol` to hygiene data.)
877 /// assert_eq!(Ident::from_str("x"), Ident::from_str("x"))
878 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x"))
879 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x").gensym())
881 /// Internally, a symbol is implemented as an index, and all operations
882 /// (including hashing, equality, and ordering) operate on that index. The use
883 /// of `newtype_index!` means that `Option<Symbol>` only takes up 4 bytes,
884 /// because `newtype_index!` reserves the last 256 values for tagging purposes.
886 /// Note that `Symbol` cannot directly be a `newtype_index!` because it
887 /// implements `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
888 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
889 pub struct Symbol(SymbolIndex);
892 pub struct SymbolIndex { .. }
896 const fn new(n: u32) -> Self {
897 Symbol(SymbolIndex::from_u32_const(n))
900 /// Maps a string to its interned representation.
901 pub fn intern(string: &str) -> Self {
902 with_interner(|interner| interner.intern(string))
905 pub fn as_str(self) -> LocalInternedString {
906 with_interner(|interner| unsafe {
907 LocalInternedString {
908 string: std::mem::transmute::<&str, &str>(interner.get(self))
913 pub fn as_interned_str(self) -> InternedString {
914 with_interner(|interner| InternedString {
915 symbol: interner.interned(self)
919 pub fn as_u32(self) -> u32 {
924 impl fmt::Debug for Symbol {
925 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
926 let is_gensymed = with_interner(|interner| interner.is_gensymed(*self));
928 write!(f, "{}({:?})", self, self.0)
930 write!(f, "{}", self)
935 impl fmt::Display for Symbol {
936 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
937 fmt::Display::fmt(&self.as_str(), f)
941 impl Encodable for Symbol {
942 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
943 s.emit_str(&self.as_str())
947 impl Decodable for Symbol {
948 fn decode<D: Decoder>(d: &mut D) -> Result<Symbol, D::Error> {
949 Ok(Symbol::intern(&d.read_str()?))
953 // The `&'static str`s in this type actually point into the arena.
955 // Note that normal symbols are indexed upward from 0, and gensyms are indexed
956 // downward from SymbolIndex::MAX_AS_U32.
958 pub struct Interner {
959 arena: DroplessArena,
960 names: FxHashMap<&'static str, Symbol>,
961 strings: Vec<&'static str>,
962 gensyms: Vec<Symbol>,
966 fn prefill(init: &[&'static str]) -> Self {
968 strings: init.into(),
969 names: init.iter().copied().zip((0..).map(Symbol::new)).collect(),
974 pub fn intern(&mut self, string: &str) -> Symbol {
975 if let Some(&name) = self.names.get(string) {
979 let name = Symbol::new(self.strings.len() as u32);
981 // `from_utf8_unchecked` is safe since we just allocated a `&str` which is known to be
983 let string: &str = unsafe {
984 str::from_utf8_unchecked(self.arena.alloc_slice(string.as_bytes()))
986 // It is safe to extend the arena allocation to `'static` because we only access
987 // these while the arena is still alive.
988 let string: &'static str = unsafe {
989 &*(string as *const str)
991 self.strings.push(string);
992 self.names.insert(string, name);
996 fn interned(&self, symbol: Symbol) -> Symbol {
997 if (symbol.0.as_usize()) < self.strings.len() {
1000 self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize]
1004 fn gensymed(&mut self, symbol: Symbol) -> Symbol {
1005 self.gensyms.push(symbol);
1006 Symbol::new(SymbolIndex::MAX_AS_U32 - self.gensyms.len() as u32 + 1)
1009 fn is_gensymed(&mut self, symbol: Symbol) -> bool {
1010 symbol.0.as_usize() >= self.strings.len()
1013 // Get the symbol as a string. `Symbol::as_str()` should be used in
1014 // preference to this function.
1015 pub fn get(&self, symbol: Symbol) -> &str {
1016 match self.strings.get(symbol.0.as_usize()) {
1017 Some(string) => string,
1019 let symbol = self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize];
1020 self.strings[symbol.0.as_usize()]
1026 // This module has a very short name because it's used a lot.
1032 // This module has a very short name because it's used a lot.
1034 use std::convert::TryInto;
1039 // Get the symbol for an integer. The first few non-negative integers each
1040 // have a static symbol and therefore are fast.
1041 pub fn integer<N: TryInto<usize> + Copy + ToString>(n: N) -> Symbol {
1042 if let Result::Ok(idx) = n.try_into() {
1043 if let Option::Some(&sym) = digits_array.get(idx) {
1047 Symbol::intern(&n.to_string())
1052 fn is_used_keyword_2018(self) -> bool {
1056 fn is_unused_keyword_2018(self) -> bool {
1057 self >= kw::Async && self <= kw::Try
1060 /// Used for sanity checking rustdoc keyword sections.
1061 pub fn is_doc_keyword(self) -> bool {
1065 /// A keyword or reserved identifier that can be used as a path segment.
1066 pub fn is_path_segment_keyword(self) -> bool {
1067 self == kw::Super ||
1068 self == kw::SelfLower ||
1069 self == kw::SelfUpper ||
1070 self == kw::Crate ||
1071 self == kw::PathRoot ||
1072 self == kw::DollarCrate
1075 /// This symbol can be a raw identifier.
1076 pub fn can_be_raw(self) -> bool {
1077 self != kw::Invalid && self != kw::Underscore && !self.is_path_segment_keyword()
1082 // Returns `true` for reserved identifiers used internally for elided lifetimes,
1083 // unnamed method parameters, crate root module, error recovery etc.
1084 pub fn is_special(self) -> bool {
1085 self.name <= kw::Underscore
1088 /// Returns `true` if the token is a keyword used in the language.
1089 pub fn is_used_keyword(self) -> bool {
1090 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1091 self.name >= kw::As && self.name <= kw::While ||
1092 self.name.is_used_keyword_2018() && self.span.rust_2018()
1095 /// Returns `true` if the token is a keyword reserved for possible future use.
1096 pub fn is_unused_keyword(self) -> bool {
1097 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1098 self.name >= kw::Abstract && self.name <= kw::Yield ||
1099 self.name.is_unused_keyword_2018() && self.span.rust_2018()
1102 /// Returns `true` if the token is either a special identifier or a keyword.
1103 pub fn is_reserved(self) -> bool {
1104 self.is_special() || self.is_used_keyword() || self.is_unused_keyword()
1107 /// A keyword or reserved identifier that can be used as a path segment.
1108 pub fn is_path_segment_keyword(self) -> bool {
1109 self.name.is_path_segment_keyword()
1112 /// We see this identifier in a normal identifier position, like variable name or a type.
1113 /// How was it written originally? Did it use the raw form? Let's try to guess.
1114 pub fn is_raw_guess(self) -> bool {
1115 self.name.can_be_raw() && self.is_reserved()
1119 // If an interner exists, return it. Otherwise, prepare a fresh one.
1121 fn with_interner<T, F: FnOnce(&mut Interner) -> T>(f: F) -> T {
1122 GLOBALS.with(|globals| f(&mut *globals.symbol_interner.lock()))
1125 /// An alternative to `Symbol` and `InternedString`, useful when the chars
1126 /// within the symbol need to be accessed. It is best used for temporary
1129 /// Because the interner outlives any thread which uses this type, we can
1130 /// safely treat `string` which points to interner data, as an immortal string,
1131 /// as long as this type never crosses between threads.
1133 // FIXME: ensure that the interner outlives any thread which uses
1134 // `LocalInternedString`, by creating a new thread right after constructing the
1136 #[derive(Clone, Copy, Hash, PartialOrd, Eq, Ord)]
1137 pub struct LocalInternedString {
1138 string: &'static str,
1141 impl LocalInternedString {
1142 /// Maps a string to its interned representation.
1143 pub fn intern(string: &str) -> Self {
1144 let string = with_interner(|interner| {
1145 let symbol = interner.intern(string);
1146 interner.strings[symbol.0.as_usize()]
1148 LocalInternedString {
1149 string: unsafe { std::mem::transmute::<&str, &str>(string) }
1153 pub fn as_interned_str(self) -> InternedString {
1155 symbol: Symbol::intern(self.string)
1160 pub fn get(&self) -> &str {
1161 // This returns a valid string since we ensure that `self` outlives the interner
1162 // by creating the interner on a thread which outlives threads which can access it.
1163 // This type cannot move to a thread which outlives the interner since it does
1164 // not implement Send.
1169 impl<U: ?Sized> std::convert::AsRef<U> for LocalInternedString
1171 str: std::convert::AsRef<U>
1174 fn as_ref(&self) -> &U {
1175 self.string.as_ref()
1179 impl<T: std::ops::Deref<Target = str>> std::cmp::PartialEq<T> for LocalInternedString {
1180 fn eq(&self, other: &T) -> bool {
1181 self.string == other.deref()
1185 impl std::cmp::PartialEq<LocalInternedString> for str {
1186 fn eq(&self, other: &LocalInternedString) -> bool {
1187 self == other.string
1191 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a str {
1192 fn eq(&self, other: &LocalInternedString) -> bool {
1193 *self == other.string
1197 impl std::cmp::PartialEq<LocalInternedString> for String {
1198 fn eq(&self, other: &LocalInternedString) -> bool {
1199 self == other.string
1203 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a String {
1204 fn eq(&self, other: &LocalInternedString) -> bool {
1205 *self == other.string
1209 impl !Send for LocalInternedString {}
1210 impl !Sync for LocalInternedString {}
1212 impl std::ops::Deref for LocalInternedString {
1215 fn deref(&self) -> &str { self.string }
1218 impl fmt::Debug for LocalInternedString {
1219 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1220 fmt::Debug::fmt(self.string, f)
1224 impl fmt::Display for LocalInternedString {
1225 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1226 fmt::Display::fmt(self.string, f)
1230 impl Decodable for LocalInternedString {
1231 fn decode<D: Decoder>(d: &mut D) -> Result<LocalInternedString, D::Error> {
1232 Ok(LocalInternedString::intern(&d.read_str()?))
1236 impl Encodable for LocalInternedString {
1237 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1238 s.emit_str(self.string)
1242 /// An alternative to `Symbol` that is focused on string contents. It has two
1243 /// main differences to `Symbol`.
1245 /// First, its implementations of `Hash`, `PartialOrd` and `Ord` work with the
1246 /// string chars rather than the symbol integer. This is useful when hash
1247 /// stability is required across compile sessions, or a guaranteed sort
1248 /// ordering is required.
1250 /// Second, gensym-ness is irrelevant. E.g.:
1252 /// assert_ne!(Symbol::gensym("x"), Symbol::gensym("x"))
1253 /// assert_eq!(Symbol::gensym("x").as_interned_str(), Symbol::gensym("x").as_interned_str())
1255 #[derive(Clone, Copy, PartialEq, Eq)]
1256 pub struct InternedString {
1260 impl InternedString {
1261 /// Maps a string to its interned representation.
1262 pub fn intern(string: &str) -> Self {
1264 symbol: Symbol::intern(string)
1268 pub fn with<F: FnOnce(&str) -> R, R>(self, f: F) -> R {
1269 let str = with_interner(|interner| {
1270 interner.get(self.symbol) as *const str
1272 // This is safe because the interner keeps string alive until it is dropped.
1273 // We can access it because we know the interner is still alive since we use a
1274 // scoped thread local to access it, and it was alive at the beginning of this scope
1278 fn with2<F: FnOnce(&str, &str) -> R, R>(self, other: &InternedString, f: F) -> R {
1279 let (self_str, other_str) = with_interner(|interner| {
1280 (interner.get(self.symbol) as *const str,
1281 interner.get(other.symbol) as *const str)
1283 // This is safe for the same reason that `with` is safe.
1284 unsafe { f(&*self_str, &*other_str) }
1287 pub fn as_symbol(self) -> Symbol {
1291 pub fn as_str(self) -> LocalInternedString {
1292 self.symbol.as_str()
1296 impl Hash for InternedString {
1297 fn hash<H: Hasher>(&self, state: &mut H) {
1298 self.with(|str| str.hash(state))
1302 impl PartialOrd<InternedString> for InternedString {
1303 fn partial_cmp(&self, other: &InternedString) -> Option<Ordering> {
1304 if self.symbol == other.symbol {
1305 return Some(Ordering::Equal);
1307 self.with2(other, |self_str, other_str| self_str.partial_cmp(other_str))
1311 impl Ord for InternedString {
1312 fn cmp(&self, other: &InternedString) -> Ordering {
1313 if self.symbol == other.symbol {
1314 return Ordering::Equal;
1316 self.with2(other, |self_str, other_str| self_str.cmp(other_str))
1320 impl fmt::Debug for InternedString {
1321 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1322 self.with(|str| fmt::Debug::fmt(&str, f))
1326 impl fmt::Display for InternedString {
1327 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1328 self.with(|str| fmt::Display::fmt(&str, f))
1332 impl Decodable for InternedString {
1333 fn decode<D: Decoder>(d: &mut D) -> Result<InternedString, D::Error> {
1334 Ok(InternedString::intern(&d.read_str()?))
1338 impl Encodable for InternedString {
1339 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1340 self.with(|string| s.emit_str(string))
1351 fn interner_tests() {
1352 let mut i: Interner = Interner::default();
1353 // first one is zero:
1354 assert_eq!(i.intern("dog"), Symbol::new(0));
1355 // re-use gets the same entry:
1356 assert_eq!(i.intern("dog"), Symbol::new(0));
1357 // different string gets a different #:
1358 assert_eq!(i.intern("cat"), Symbol::new(1));
1359 assert_eq!(i.intern("cat"), Symbol::new(1));
1360 // dog is still at zero
1361 assert_eq!(i.intern("dog"), Symbol::new(0));
1362 let z = i.intern("zebra");
1363 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32));
1364 // gensym of same string gets new number:
1365 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32 - 1));
1366 // gensym of *existing* string gets new number:
1367 let d = i.intern("dog");
1368 assert_eq!(i.gensymed(d), Symbol::new(SymbolIndex::MAX_AS_U32 - 2));
1372 fn without_first_quote_test() {
1373 GLOBALS.set(&Globals::new(edition::DEFAULT_EDITION), || {
1374 let i = Ident::from_str("'break");
1375 assert_eq!(i.without_first_quote().name, kw::Break);