1//! Defines lang items.
2//!
3//! Language items are items that represent concepts intrinsic to the language
4//! itself. Examples are:
5//!
6//! * Traits that specify "kinds"; e.g., `Sync`, `Send`.
7//! * Traits that represent operators; e.g., `Add`, `Sub`, `Index`.
8//! * Functions called by the compiler itself.
9
10use rustc_ast::attr::AttributeExt;
11use rustc_data_structures::fx::FxIndexMap;
12use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
13use rustc_macros::{Decodable, Encodable, HashStable_Generic};
14use rustc_span::{Span, Symbol, kw, sym};
15
16use crate::def_id::DefId;
17use crate::{MethodKind, Target};
18
19/// All of the lang items, defined or not.
20/// Defined lang items can come from the current crate or its dependencies.
21#[derive(HashStable_Generic, Debug)]
22pub struct LanguageItems {
23 /// Mappings from lang items to their possibly found [`DefId`]s.
24 /// The index corresponds to the order in [`LangItem`].
25 items: [Option<DefId>; std::mem::variant_count::<LangItem>()],
26 reverse_items: FxIndexMap<DefId, LangItem>,
27 /// Lang items that were not found during collection.
28 pub missing: Vec<LangItem>,
29}
30
31impl LanguageItems {
32 /// Construct an empty collection of lang items and no missing ones.
33 pub fn new() -> Self {
34 Self {
35 items: [None; std::mem::variant_count::<LangItem>()],
36 reverse_items: FxIndexMap::default(),
37 missing: Vec::new(),
38 }
39 }
40
41 pub fn get(&self, item: LangItem) -> Option<DefId> {
42 self.items[item as usize]
43 }
44
45 pub fn set(&mut self, item: LangItem, def_id: DefId) {
46 self.items[item as usize] = Some(def_id);
47 let preexisting = self.reverse_items.insert(def_id, item);
48
49 // This needs to be a bijection.
50 if let Some(preexisting) = preexisting {
51 panic!(
52 "For the bijection of LangItem <=> DefId to work,\
53 one item DefId may only be assigned one LangItem. \
54 Separate the LangItem definitions for {item:?} and {preexisting:?}."
55 );
56 }
57 }
58
59 pub fn from_def_id(&self, def_id: DefId) -> Option<LangItem> {
60 self.reverse_items.get(&def_id).copied()
61 }
62
63 pub fn iter(&self) -> impl Iterator<Item = (LangItem, DefId)> {
64 self.items
65 .iter()
66 .enumerate()
67 .filter_map(|(i, id)| id.map(|id| (LangItem::from_u32(i as u32).unwrap(), id)))
68 }
69}
70
71// The actual lang items defined come at the end of this file in one handy table.
72// So you probably just want to nip down to the end.
73macro_rules! language_item_table {
74 (
75 $( $(#[$attr:meta])* $variant:ident, $module:ident :: $name:ident, $method:ident, $target:expr, $generics:expr; )*
76 ) => {
77 /// A representation of all the valid lang items in Rust.
78 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable)]
79 pub enum LangItem {
80 $(
81 #[doc = concat!("The `", stringify!($name), "` lang item.")]
82 $(#[$attr])*
83 $variant,
84 )*
85 }
86
87 impl LangItem {
88 fn from_u32(u: u32) -> Option<LangItem> {
89 // This implementation is clumsy, but makes no assumptions
90 // about how discriminant tags are allocated within the
91 // range `0 .. std::mem::variant_count::<LangItem>()`.
92 $(if u == LangItem::$variant as u32 {
93 return Some(LangItem::$variant)
94 })*
95 None
96 }
97
98 /// Returns the `name` symbol in `#[lang = "$name"]`.
99 /// For example, [`LangItem::PartialEq`]`.name()`
100 /// would result in [`sym::eq`] since it is `#[lang = "eq"]`.
101 pub fn name(self) -> Symbol {
102 match self {
103 $( LangItem::$variant => $module::$name, )*
104 }
105 }
106
107 /// Opposite of [`LangItem::name`]
108 pub fn from_name(name: Symbol) -> Option<Self> {
109 match name {
110 $( $module::$name => Some(LangItem::$variant), )*
111 _ => None,
112 }
113 }
114
115 /// Returns the name of the `LangItem` enum variant.
116 // This method is used by Clippy for internal lints.
117 pub fn variant_name(self) -> &'static str {
118 match self {
119 $( LangItem::$variant => stringify!($variant), )*
120 }
121 }
122
123 pub fn target(self) -> Target {
124 match self {
125 $( LangItem::$variant => $target, )*
126 }
127 }
128
129 pub fn required_generics(&self) -> GenericRequirement {
130 match self {
131 $( LangItem::$variant => $generics, )*
132 }
133 }
134 }
135
136 impl LanguageItems {
137 $(
138 #[doc = concat!("Returns the [`DefId`] of the `", stringify!($name), "` lang item if it is defined.")]
139 pub fn $method(&self) -> Option<DefId> {
140 self.items[LangItem::$variant as usize]
141 }
142 )*
143 }
144 }
145}
146
147impl<CTX> HashStable<CTX> for LangItem {
148 fn hash_stable(&self, _: &mut CTX, hasher: &mut StableHasher) {
149 ::std::hash::Hash::hash(self, state:hasher);
150 }
151}
152
153/// Extracts the first `lang = "$name"` out of a list of attributes.
154/// The `#[panic_handler]` attribute is also extracted out when found.
155pub fn extract(attrs: &[impl AttributeExt]) -> Option<(Symbol, Span)> {
156 attrs.iter().find_map(|attr: &impl AttributeExt| {
157 Some(match attr {
158 _ if attr.has_name(sym::lang) => (attr.value_str()?, attr.span()),
159 _ if attr.has_name(sym::panic_handler) => (sym::panic_impl, attr.span()),
160 _ => return None,
161 })
162 })
163}
164
165language_item_table! {
166// Variant name, Name, Getter method name, Target Generic requirements;
167 Sized, sym::sized, sized_trait, Target::Trait, GenericRequirement::Exact(0);
168 Unsize, sym::unsize, unsize_trait, Target::Trait, GenericRequirement::Minimum(1);
169 /// Trait injected by `#[derive(PartialEq)]`, (i.e. "Partial EQ").
170 StructuralPeq, sym::structural_peq, structural_peq_trait, Target::Trait, GenericRequirement::None;
171 Copy, sym::copy, copy_trait, Target::Trait, GenericRequirement::Exact(0);
172 Clone, sym::clone, clone_trait, Target::Trait, GenericRequirement::None;
173 CloneFn, sym::clone_fn, clone_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
174 UseCloned, sym::use_cloned, use_cloned_trait, Target::Trait, GenericRequirement::None;
175 Sync, sym::sync, sync_trait, Target::Trait, GenericRequirement::Exact(0);
176 DiscriminantKind, sym::discriminant_kind, discriminant_kind_trait, Target::Trait, GenericRequirement::None;
177 /// The associated item of the `DiscriminantKind` trait.
178 Discriminant, sym::discriminant_type, discriminant_type, Target::AssocTy, GenericRequirement::None;
179
180 PointeeTrait, sym::pointee_trait, pointee_trait, Target::Trait, GenericRequirement::None;
181 Metadata, sym::metadata_type, metadata_type, Target::AssocTy, GenericRequirement::None;
182 DynMetadata, sym::dyn_metadata, dyn_metadata, Target::Struct, GenericRequirement::None;
183
184 Freeze, sym::freeze, freeze_trait, Target::Trait, GenericRequirement::Exact(0);
185
186 FnPtrTrait, sym::fn_ptr_trait, fn_ptr_trait, Target::Trait, GenericRequirement::Exact(0);
187 FnPtrAddr, sym::fn_ptr_addr, fn_ptr_addr, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
188
189 Drop, sym::drop, drop_trait, Target::Trait, GenericRequirement::None;
190 Destruct, sym::destruct, destruct_trait, Target::Trait, GenericRequirement::None;
191
192 AsyncDrop, sym::async_drop, async_drop_trait, Target::Trait, GenericRequirement::Exact(0);
193 AsyncDestruct, sym::async_destruct, async_destruct_trait, Target::Trait, GenericRequirement::Exact(0);
194 AsyncDropInPlace, sym::async_drop_in_place, async_drop_in_place_fn, Target::Fn, GenericRequirement::Exact(1);
195 SurfaceAsyncDropInPlace, sym::surface_async_drop_in_place, surface_async_drop_in_place_fn, Target::Fn, GenericRequirement::Exact(1);
196 AsyncDropSurfaceDropInPlace, sym::async_drop_surface_drop_in_place, async_drop_surface_drop_in_place_fn, Target::Fn, GenericRequirement::Exact(1);
197 AsyncDropSlice, sym::async_drop_slice, async_drop_slice_fn, Target::Fn, GenericRequirement::Exact(1);
198 AsyncDropChain, sym::async_drop_chain, async_drop_chain_fn, Target::Fn, GenericRequirement::Exact(2);
199 AsyncDropNoop, sym::async_drop_noop, async_drop_noop_fn, Target::Fn, GenericRequirement::Exact(0);
200 AsyncDropDeferredDropInPlace, sym::async_drop_deferred_drop_in_place, async_drop_deferred_drop_in_place_fn, Target::Fn, GenericRequirement::Exact(1);
201 AsyncDropFuse, sym::async_drop_fuse, async_drop_fuse_fn, Target::Fn, GenericRequirement::Exact(1);
202 AsyncDropDefer, sym::async_drop_defer, async_drop_defer_fn, Target::Fn, GenericRequirement::Exact(1);
203 AsyncDropEither, sym::async_drop_either, async_drop_either_fn, Target::Fn, GenericRequirement::Exact(3);
204
205 CoerceUnsized, sym::coerce_unsized, coerce_unsized_trait, Target::Trait, GenericRequirement::Minimum(1);
206 DispatchFromDyn, sym::dispatch_from_dyn, dispatch_from_dyn_trait, Target::Trait, GenericRequirement::Minimum(1);
207
208 // lang items relating to transmutability
209 TransmuteOpts, sym::transmute_opts, transmute_opts, Target::Struct, GenericRequirement::Exact(0);
210 TransmuteTrait, sym::transmute_trait, transmute_trait, Target::Trait, GenericRequirement::Exact(2);
211
212 Add, sym::add, add_trait, Target::Trait, GenericRequirement::Exact(1);
213 Sub, sym::sub, sub_trait, Target::Trait, GenericRequirement::Exact(1);
214 Mul, sym::mul, mul_trait, Target::Trait, GenericRequirement::Exact(1);
215 Div, sym::div, div_trait, Target::Trait, GenericRequirement::Exact(1);
216 Rem, sym::rem, rem_trait, Target::Trait, GenericRequirement::Exact(1);
217 Neg, sym::neg, neg_trait, Target::Trait, GenericRequirement::Exact(0);
218 Not, sym::not, not_trait, Target::Trait, GenericRequirement::Exact(0);
219 BitXor, sym::bitxor, bitxor_trait, Target::Trait, GenericRequirement::Exact(1);
220 BitAnd, sym::bitand, bitand_trait, Target::Trait, GenericRequirement::Exact(1);
221 BitOr, sym::bitor, bitor_trait, Target::Trait, GenericRequirement::Exact(1);
222 Shl, sym::shl, shl_trait, Target::Trait, GenericRequirement::Exact(1);
223 Shr, sym::shr, shr_trait, Target::Trait, GenericRequirement::Exact(1);
224 AddAssign, sym::add_assign, add_assign_trait, Target::Trait, GenericRequirement::Exact(1);
225 SubAssign, sym::sub_assign, sub_assign_trait, Target::Trait, GenericRequirement::Exact(1);
226 MulAssign, sym::mul_assign, mul_assign_trait, Target::Trait, GenericRequirement::Exact(1);
227 DivAssign, sym::div_assign, div_assign_trait, Target::Trait, GenericRequirement::Exact(1);
228 RemAssign, sym::rem_assign, rem_assign_trait, Target::Trait, GenericRequirement::Exact(1);
229 BitXorAssign, sym::bitxor_assign, bitxor_assign_trait, Target::Trait, GenericRequirement::Exact(1);
230 BitAndAssign, sym::bitand_assign, bitand_assign_trait, Target::Trait, GenericRequirement::Exact(1);
231 BitOrAssign, sym::bitor_assign, bitor_assign_trait, Target::Trait, GenericRequirement::Exact(1);
232 ShlAssign, sym::shl_assign, shl_assign_trait, Target::Trait, GenericRequirement::Exact(1);
233 ShrAssign, sym::shr_assign, shr_assign_trait, Target::Trait, GenericRequirement::Exact(1);
234 Index, sym::index, index_trait, Target::Trait, GenericRequirement::Exact(1);
235 IndexMut, sym::index_mut, index_mut_trait, Target::Trait, GenericRequirement::Exact(1);
236
237 UnsafeCell, sym::unsafe_cell, unsafe_cell_type, Target::Struct, GenericRequirement::None;
238 VaList, sym::va_list, va_list, Target::Struct, GenericRequirement::None;
239
240 Deref, sym::deref, deref_trait, Target::Trait, GenericRequirement::Exact(0);
241 DerefMut, sym::deref_mut, deref_mut_trait, Target::Trait, GenericRequirement::Exact(0);
242 DerefPure, sym::deref_pure, deref_pure_trait, Target::Trait, GenericRequirement::Exact(0);
243 DerefTarget, sym::deref_target, deref_target, Target::AssocTy, GenericRequirement::None;
244 Receiver, sym::receiver, receiver_trait, Target::Trait, GenericRequirement::None;
245 ReceiverTarget, sym::receiver_target, receiver_target, Target::AssocTy, GenericRequirement::None;
246 LegacyReceiver, sym::legacy_receiver, legacy_receiver_trait, Target::Trait, GenericRequirement::None;
247
248 Fn, kw::Fn, fn_trait, Target::Trait, GenericRequirement::Exact(1);
249 FnMut, sym::fn_mut, fn_mut_trait, Target::Trait, GenericRequirement::Exact(1);
250 FnOnce, sym::fn_once, fn_once_trait, Target::Trait, GenericRequirement::Exact(1);
251
252 AsyncFn, sym::async_fn, async_fn_trait, Target::Trait, GenericRequirement::Exact(1);
253 AsyncFnMut, sym::async_fn_mut, async_fn_mut_trait, Target::Trait, GenericRequirement::Exact(1);
254 AsyncFnOnce, sym::async_fn_once, async_fn_once_trait, Target::Trait, GenericRequirement::Exact(1);
255 AsyncFnOnceOutput, sym::async_fn_once_output, async_fn_once_output, Target::AssocTy, GenericRequirement::Exact(1);
256 CallOnceFuture, sym::call_once_future, call_once_future, Target::AssocTy, GenericRequirement::Exact(1);
257 CallRefFuture, sym::call_ref_future, call_ref_future, Target::AssocTy, GenericRequirement::Exact(2);
258 AsyncFnKindHelper, sym::async_fn_kind_helper, async_fn_kind_helper, Target::Trait, GenericRequirement::Exact(1);
259 AsyncFnKindUpvars, sym::async_fn_kind_upvars, async_fn_kind_upvars, Target::AssocTy, GenericRequirement::Exact(5);
260
261 FnOnceOutput, sym::fn_once_output, fn_once_output, Target::AssocTy, GenericRequirement::None;
262
263 Iterator, sym::iterator, iterator_trait, Target::Trait, GenericRequirement::Exact(0);
264 FusedIterator, sym::fused_iterator, fused_iterator_trait, Target::Trait, GenericRequirement::Exact(0);
265 Future, sym::future_trait, future_trait, Target::Trait, GenericRequirement::Exact(0);
266 FutureOutput, sym::future_output, future_output, Target::AssocTy, GenericRequirement::Exact(0);
267 AsyncIterator, sym::async_iterator, async_iterator_trait, Target::Trait, GenericRequirement::Exact(0);
268
269 CoroutineState, sym::coroutine_state, coroutine_state, Target::Enum, GenericRequirement::None;
270 Coroutine, sym::coroutine, coroutine_trait, Target::Trait, GenericRequirement::Exact(1);
271 CoroutineReturn, sym::coroutine_return, coroutine_return, Target::AssocTy, GenericRequirement::Exact(1);
272 CoroutineYield, sym::coroutine_yield, coroutine_yield, Target::AssocTy, GenericRequirement::Exact(1);
273 CoroutineResume, sym::coroutine_resume, coroutine_resume, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
274
275 Unpin, sym::unpin, unpin_trait, Target::Trait, GenericRequirement::None;
276 Pin, sym::pin, pin_type, Target::Struct, GenericRequirement::None;
277
278 OrderingEnum, sym::Ordering, ordering_enum, Target::Enum, GenericRequirement::Exact(0);
279 PartialEq, sym::eq, eq_trait, Target::Trait, GenericRequirement::Exact(1);
280 PartialOrd, sym::partial_ord, partial_ord_trait, Target::Trait, GenericRequirement::Exact(1);
281 CVoid, sym::c_void, c_void, Target::Enum, GenericRequirement::None;
282
283 // A number of panic-related lang items. The `panic` item corresponds to divide-by-zero and
284 // various panic cases with `match`. The `panic_bounds_check` item is for indexing arrays.
285 //
286 // The `begin_unwind` lang item has a predefined symbol name and is sort of a "weak lang item"
287 // in the sense that a crate is not required to have it defined to use it, but a final product
288 // is required to define it somewhere. Additionally, there are restrictions on crates that use
289 // a weak lang item, but do not have it defined.
290 Panic, sym::panic, panic_fn, Target::Fn, GenericRequirement::Exact(0);
291 PanicNounwind, sym::panic_nounwind, panic_nounwind, Target::Fn, GenericRequirement::Exact(0);
292 PanicFmt, sym::panic_fmt, panic_fmt, Target::Fn, GenericRequirement::None;
293 ConstPanicFmt, sym::const_panic_fmt, const_panic_fmt, Target::Fn, GenericRequirement::None;
294 PanicBoundsCheck, sym::panic_bounds_check, panic_bounds_check_fn, Target::Fn, GenericRequirement::Exact(0);
295 PanicMisalignedPointerDereference, sym::panic_misaligned_pointer_dereference, panic_misaligned_pointer_dereference_fn, Target::Fn, GenericRequirement::Exact(0);
296 PanicInfo, sym::panic_info, panic_info, Target::Struct, GenericRequirement::None;
297 PanicLocation, sym::panic_location, panic_location, Target::Struct, GenericRequirement::None;
298 PanicImpl, sym::panic_impl, panic_impl, Target::Fn, GenericRequirement::None;
299 PanicCannotUnwind, sym::panic_cannot_unwind, panic_cannot_unwind, Target::Fn, GenericRequirement::Exact(0);
300 PanicInCleanup, sym::panic_in_cleanup, panic_in_cleanup, Target::Fn, GenericRequirement::Exact(0);
301 /// Constant panic messages, used for codegen of MIR asserts.
302 PanicAddOverflow, sym::panic_const_add_overflow, panic_const_add_overflow, Target::Fn, GenericRequirement::None;
303 PanicSubOverflow, sym::panic_const_sub_overflow, panic_const_sub_overflow, Target::Fn, GenericRequirement::None;
304 PanicMulOverflow, sym::panic_const_mul_overflow, panic_const_mul_overflow, Target::Fn, GenericRequirement::None;
305 PanicDivOverflow, sym::panic_const_div_overflow, panic_const_div_overflow, Target::Fn, GenericRequirement::None;
306 PanicRemOverflow, sym::panic_const_rem_overflow, panic_const_rem_overflow, Target::Fn, GenericRequirement::None;
307 PanicNegOverflow, sym::panic_const_neg_overflow, panic_const_neg_overflow, Target::Fn, GenericRequirement::None;
308 PanicShrOverflow, sym::panic_const_shr_overflow, panic_const_shr_overflow, Target::Fn, GenericRequirement::None;
309 PanicShlOverflow, sym::panic_const_shl_overflow, panic_const_shl_overflow, Target::Fn, GenericRequirement::None;
310 PanicDivZero, sym::panic_const_div_by_zero, panic_const_div_by_zero, Target::Fn, GenericRequirement::None;
311 PanicRemZero, sym::panic_const_rem_by_zero, panic_const_rem_by_zero, Target::Fn, GenericRequirement::None;
312 PanicCoroutineResumed, sym::panic_const_coroutine_resumed, panic_const_coroutine_resumed, Target::Fn, GenericRequirement::None;
313 PanicAsyncFnResumed, sym::panic_const_async_fn_resumed, panic_const_async_fn_resumed, Target::Fn, GenericRequirement::None;
314 PanicAsyncGenFnResumed, sym::panic_const_async_gen_fn_resumed, panic_const_async_gen_fn_resumed, Target::Fn, GenericRequirement::None;
315 PanicGenFnNone, sym::panic_const_gen_fn_none, panic_const_gen_fn_none, Target::Fn, GenericRequirement::None;
316 PanicCoroutineResumedPanic, sym::panic_const_coroutine_resumed_panic, panic_const_coroutine_resumed_panic, Target::Fn, GenericRequirement::None;
317 PanicAsyncFnResumedPanic, sym::panic_const_async_fn_resumed_panic, panic_const_async_fn_resumed_panic, Target::Fn, GenericRequirement::None;
318 PanicAsyncGenFnResumedPanic, sym::panic_const_async_gen_fn_resumed_panic, panic_const_async_gen_fn_resumed_panic, Target::Fn, GenericRequirement::None;
319 PanicGenFnNonePanic, sym::panic_const_gen_fn_none_panic, panic_const_gen_fn_none_panic, Target::Fn, GenericRequirement::None;
320 PanicNullPointerDereference, sym::panic_null_pointer_dereference, panic_null_pointer_dereference, Target::Fn, GenericRequirement::None;
321 /// libstd panic entry point. Necessary for const eval to be able to catch it
322 BeginPanic, sym::begin_panic, begin_panic_fn, Target::Fn, GenericRequirement::None;
323
324 // Lang items needed for `format_args!()`.
325 FormatArgument, sym::format_argument, format_argument, Target::Struct, GenericRequirement::None;
326 FormatArguments, sym::format_arguments, format_arguments, Target::Struct, GenericRequirement::None;
327 FormatCount, sym::format_count, format_count, Target::Enum, GenericRequirement::None;
328 FormatPlaceholder, sym::format_placeholder, format_placeholder, Target::Struct, GenericRequirement::None;
329 FormatUnsafeArg, sym::format_unsafe_arg, format_unsafe_arg, Target::Struct, GenericRequirement::None;
330
331 ExchangeMalloc, sym::exchange_malloc, exchange_malloc_fn, Target::Fn, GenericRequirement::None;
332 DropInPlace, sym::drop_in_place, drop_in_place_fn, Target::Fn, GenericRequirement::Minimum(1);
333 FallbackSurfaceDrop, sym::fallback_surface_drop, fallback_surface_drop_fn, Target::Fn, GenericRequirement::None;
334 AllocLayout, sym::alloc_layout, alloc_layout, Target::Struct, GenericRequirement::None;
335
336 /// For all binary crates without `#![no_main]`, Rust will generate a "main" function.
337 /// The exact name and signature are target-dependent. The "main" function will invoke
338 /// this lang item, passing it the `argc` and `argv` (or null, if those don't exist
339 /// on the current target) as well as the user-defined `fn main` from the binary crate.
340 Start, sym::start, start_fn, Target::Fn, GenericRequirement::Exact(1);
341
342 EhPersonality, sym::eh_personality, eh_personality, Target::Fn, GenericRequirement::None;
343 EhCatchTypeinfo, sym::eh_catch_typeinfo, eh_catch_typeinfo, Target::Static, GenericRequirement::None;
344
345 OwnedBox, sym::owned_box, owned_box, Target::Struct, GenericRequirement::Minimum(1);
346 GlobalAlloc, sym::global_alloc_ty, global_alloc_ty, Target::Struct, GenericRequirement::None;
347
348 // Experimental lang item for Miri
349 PtrUnique, sym::ptr_unique, ptr_unique, Target::Struct, GenericRequirement::Exact(1);
350
351 PhantomData, sym::phantom_data, phantom_data, Target::Struct, GenericRequirement::Exact(1);
352
353 ManuallyDrop, sym::manually_drop, manually_drop, Target::Struct, GenericRequirement::None;
354 BikeshedGuaranteedNoDrop, sym::bikeshed_guaranteed_no_drop, bikeshed_guaranteed_no_drop, Target::Trait, GenericRequirement::Exact(0);
355
356 MaybeUninit, sym::maybe_uninit, maybe_uninit, Target::Union, GenericRequirement::None;
357
358 Termination, sym::termination, termination, Target::Trait, GenericRequirement::None;
359
360 Try, sym::Try, try_trait, Target::Trait, GenericRequirement::None;
361
362 Tuple, sym::tuple_trait, tuple_trait, Target::Trait, GenericRequirement::Exact(0);
363
364 SliceLen, sym::slice_len_fn, slice_len_fn, Target::Method(MethodKind::Inherent), GenericRequirement::None;
365
366 // Language items from AST lowering
367 TryTraitFromResidual, sym::from_residual, from_residual_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
368 TryTraitFromOutput, sym::from_output, from_output_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
369 TryTraitBranch, sym::branch, branch_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
370 TryTraitFromYeet, sym::from_yeet, from_yeet_fn, Target::Fn, GenericRequirement::None;
371
372 PointerLike, sym::pointer_like, pointer_like, Target::Trait, GenericRequirement::Exact(0);
373
374 CoercePointeeValidated, sym::coerce_pointee_validated, coerce_pointee_validated_trait, Target::Trait, GenericRequirement::Exact(0);
375
376 ConstParamTy, sym::const_param_ty, const_param_ty_trait, Target::Trait, GenericRequirement::Exact(0);
377 UnsizedConstParamTy, sym::unsized_const_param_ty, unsized_const_param_ty_trait, Target::Trait, GenericRequirement::Exact(0);
378
379 Poll, sym::Poll, poll, Target::Enum, GenericRequirement::None;
380 PollReady, sym::Ready, poll_ready_variant, Target::Variant, GenericRequirement::None;
381 PollPending, sym::Pending, poll_pending_variant, Target::Variant, GenericRequirement::None;
382
383 AsyncGenReady, sym::AsyncGenReady, async_gen_ready, Target::Method(MethodKind::Inherent), GenericRequirement::Exact(1);
384 AsyncGenPending, sym::AsyncGenPending, async_gen_pending, Target::AssocConst, GenericRequirement::Exact(1);
385 AsyncGenFinished, sym::AsyncGenFinished, async_gen_finished, Target::AssocConst, GenericRequirement::Exact(1);
386
387 // FIXME(swatinem): the following lang items are used for async lowering and
388 // should become obsolete eventually.
389 ResumeTy, sym::ResumeTy, resume_ty, Target::Struct, GenericRequirement::None;
390 GetContext, sym::get_context, get_context_fn, Target::Fn, GenericRequirement::None;
391
392 Context, sym::Context, context, Target::Struct, GenericRequirement::None;
393 FuturePoll, sym::poll, future_poll_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
394
395 AsyncIteratorPollNext, sym::async_iterator_poll_next, async_iterator_poll_next, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::Exact(0);
396 IntoAsyncIterIntoIter, sym::into_async_iter_into_iter, into_async_iter_into_iter, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::Exact(0);
397
398 Option, sym::Option, option_type, Target::Enum, GenericRequirement::None;
399 OptionSome, sym::Some, option_some_variant, Target::Variant, GenericRequirement::None;
400 OptionNone, sym::None, option_none_variant, Target::Variant, GenericRequirement::None;
401
402 ResultOk, sym::Ok, result_ok_variant, Target::Variant, GenericRequirement::None;
403 ResultErr, sym::Err, result_err_variant, Target::Variant, GenericRequirement::None;
404
405 ControlFlowContinue, sym::Continue, cf_continue_variant, Target::Variant, GenericRequirement::None;
406 ControlFlowBreak, sym::Break, cf_break_variant, Target::Variant, GenericRequirement::None;
407
408 IntoFutureIntoFuture, sym::into_future, into_future_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
409 IntoIterIntoIter, sym::into_iter, into_iter_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
410 IteratorNext, sym::next, next_fn, Target::Method(MethodKind::Trait { body: false}), GenericRequirement::None;
411
412 PinNewUnchecked, sym::new_unchecked, new_unchecked_fn, Target::Method(MethodKind::Inherent), GenericRequirement::None;
413
414 RangeFrom, sym::RangeFrom, range_from_struct, Target::Struct, GenericRequirement::None;
415 RangeFull, sym::RangeFull, range_full_struct, Target::Struct, GenericRequirement::None;
416 RangeInclusiveStruct, sym::RangeInclusive, range_inclusive_struct, Target::Struct, GenericRequirement::None;
417 RangeInclusiveNew, sym::range_inclusive_new, range_inclusive_new_method, Target::Method(MethodKind::Inherent), GenericRequirement::None;
418 Range, sym::Range, range_struct, Target::Struct, GenericRequirement::None;
419 RangeToInclusive, sym::RangeToInclusive, range_to_inclusive_struct, Target::Struct, GenericRequirement::None;
420 RangeTo, sym::RangeTo, range_to_struct, Target::Struct, GenericRequirement::None;
421 RangeMax, sym::RangeMax, range_max, Target::AssocConst, GenericRequirement::Exact(0);
422 RangeMin, sym::RangeMin, range_min, Target::AssocConst, GenericRequirement::Exact(0);
423 RangeSub, sym::RangeSub, range_sub, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::Exact(0);
424
425 // `new_range` types that are `Copy + IntoIterator`
426 RangeFromCopy, sym::RangeFromCopy, range_from_copy_struct, Target::Struct, GenericRequirement::None;
427 RangeCopy, sym::RangeCopy, range_copy_struct, Target::Struct, GenericRequirement::None;
428 RangeInclusiveCopy, sym::RangeInclusiveCopy, range_inclusive_copy_struct, Target::Struct, GenericRequirement::None;
429
430 String, sym::String, string, Target::Struct, GenericRequirement::None;
431 CStr, sym::CStr, c_str, Target::Struct, GenericRequirement::None;
432
433 // Experimental lang items for implementing contract pre- and post-condition checking.
434 ContractBuildCheckEnsures, sym::contract_build_check_ensures, contract_build_check_ensures_fn, Target::Fn, GenericRequirement::None;
435 ContractCheckRequires, sym::contract_check_requires, contract_check_requires_fn, Target::Fn, GenericRequirement::None;
436}
437
438/// The requirement imposed on the generics of a lang item
439pub enum GenericRequirement {
440 /// No restriction on the generics
441 None,
442 /// A minimum number of generics that is demanded on a lang item
443 Minimum(usize),
444 /// The number of generics must match precisely as stipulated
445 Exact(usize),
446}
447
448pub static FN_TRAITS: &'static [LangItem] = &[LangItem::Fn, LangItem::FnMut, LangItem::FnOnce];
449
450pub static OPERATORS: &'static [LangItem] = &[
451 LangItem::Add,
452 LangItem::Sub,
453 LangItem::Mul,
454 LangItem::Div,
455 LangItem::Rem,
456 LangItem::Neg,
457 LangItem::Not,
458 LangItem::BitXor,
459 LangItem::BitAnd,
460 LangItem::BitOr,
461 LangItem::Shl,
462 LangItem::Shr,
463 LangItem::AddAssign,
464 LangItem::SubAssign,
465 LangItem::MulAssign,
466 LangItem::DivAssign,
467 LangItem::RemAssign,
468 LangItem::BitXorAssign,
469 LangItem::BitAndAssign,
470 LangItem::BitOrAssign,
471 LangItem::ShlAssign,
472 LangItem::ShrAssign,
473 LangItem::Index,
474 LangItem::IndexMut,
475 LangItem::PartialEq,
476 LangItem::PartialOrd,
477];
478
479pub static BINARY_OPERATORS: &'static [LangItem] = &[
480 LangItem::Add,
481 LangItem::Sub,
482 LangItem::Mul,
483 LangItem::Div,
484 LangItem::Rem,
485 LangItem::BitXor,
486 LangItem::BitAnd,
487 LangItem::BitOr,
488 LangItem::Shl,
489 LangItem::Shr,
490 LangItem::AddAssign,
491 LangItem::SubAssign,
492 LangItem::MulAssign,
493 LangItem::DivAssign,
494 LangItem::RemAssign,
495 LangItem::BitXorAssign,
496 LangItem::BitAndAssign,
497 LangItem::BitOrAssign,
498 LangItem::ShlAssign,
499 LangItem::ShrAssign,
500 LangItem::Index,
501 LangItem::IndexMut,
502 LangItem::PartialEq,
503 LangItem::PartialOrd,
504];
505