rustc_hir/def.rs
1use std::array::IntoIter;
2use std::fmt::Debug;
3
4use rustc_ast as ast;
5use rustc_ast::NodeId;
6use rustc_data_structures::stable_hasher::ToStableHashKey;
7use rustc_data_structures::unord::UnordMap;
8use rustc_macros::{Decodable, Encodable, HashStable_Generic};
9use rustc_span::Symbol;
10use rustc_span::def_id::{DefId, LocalDefId};
11use rustc_span::hygiene::MacroKind;
12
13use crate::definitions::DefPathData;
14use crate::hir;
15
16/// Encodes if a `DefKind::Ctor` is the constructor of an enum variant or a struct.
17#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug, HashStable_Generic)]
18pub enum CtorOf {
19 /// This `DefKind::Ctor` is a synthesized constructor of a tuple or unit struct.
20 Struct,
21 /// This `DefKind::Ctor` is a synthesized constructor of a tuple or unit variant.
22 Variant,
23}
24
25/// What kind of constructor something is.
26#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug, HashStable_Generic)]
27pub enum CtorKind {
28 /// Constructor function automatically created by a tuple struct/variant.
29 Fn,
30 /// Constructor constant automatically created by a unit struct/variant.
31 Const,
32}
33
34/// An attribute that is not a macro; e.g., `#[inline]` or `#[rustfmt::skip]`.
35#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug, HashStable_Generic)]
36pub enum NonMacroAttrKind {
37 /// Single-segment attribute defined by the language (`#[inline]`)
38 Builtin(Symbol),
39 /// Multi-segment custom attribute living in a "tool module" (`#[rustfmt::skip]`).
40 Tool,
41 /// Single-segment custom attribute registered by a derive macro (`#[serde(default)]`).
42 DeriveHelper,
43 /// Single-segment custom attribute registered by a derive macro
44 /// but used before that derive macro was expanded (deprecated).
45 DeriveHelperCompat,
46}
47
48/// What kind of definition something is; e.g., `mod` vs `struct`.
49/// `enum DefPathData` may need to be updated if a new variant is added here.
50#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug, HashStable_Generic)]
51pub enum DefKind {
52 // Type namespace
53 Mod,
54 /// Refers to the struct itself, [`DefKind::Ctor`] refers to its constructor if it exists.
55 Struct,
56 Union,
57 Enum,
58 /// Refers to the variant itself, [`DefKind::Ctor`] refers to its constructor if it exists.
59 Variant,
60 Trait,
61 /// Type alias: `type Foo = Bar;`
62 TyAlias,
63 /// Type from an `extern` block.
64 ForeignTy,
65 /// Trait alias: `trait IntIterator = Iterator<Item = i32>;`
66 TraitAlias,
67 /// Associated type: `trait MyTrait { type Assoc; }`
68 AssocTy,
69 /// Type parameter: the `T` in `struct Vec<T> { ... }`
70 TyParam,
71
72 // Value namespace
73 Fn,
74 Const,
75 /// Constant generic parameter: `struct Foo<const N: usize> { ... }`
76 ConstParam,
77 Static {
78 /// Whether it's a `unsafe static`, `safe static` (inside extern only) or just a `static`.
79 safety: hir::Safety,
80 /// Whether it's a `static mut` or just a `static`.
81 mutability: ast::Mutability,
82 /// Whether it's an anonymous static generated for nested allocations.
83 nested: bool,
84 },
85 /// Refers to the struct or enum variant's constructor.
86 ///
87 /// The reason `Ctor` exists in addition to [`DefKind::Struct`] and
88 /// [`DefKind::Variant`] is because structs and enum variants exist
89 /// in the *type* namespace, whereas struct and enum variant *constructors*
90 /// exist in the *value* namespace.
91 ///
92 /// You may wonder why enum variants exist in the type namespace as opposed
93 /// to the value namespace. Check out [RFC 2593] for intuition on why that is.
94 ///
95 /// [RFC 2593]: https://github.com/rust-lang/rfcs/pull/2593
96 Ctor(CtorOf, CtorKind),
97 /// Associated function: `impl MyStruct { fn associated() {} }`
98 /// or `trait Foo { fn associated() {} }`
99 AssocFn,
100 /// Associated constant: `trait MyTrait { const ASSOC: usize; }`
101 AssocConst,
102
103 // Macro namespace
104 Macro(MacroKind),
105
106 // Not namespaced (or they are, but we don't treat them so)
107 ExternCrate,
108 Use,
109 /// An `extern` block.
110 ForeignMod,
111 /// Anonymous constant, e.g. the `1 + 2` in `[u8; 1 + 2]`.
112 ///
113 /// Not all anon-consts are actually still relevant in the HIR. We lower
114 /// trivial const-arguments directly to `hir::ConstArgKind::Path`, at which
115 /// point the definition for the anon-const ends up unused and incomplete.
116 ///
117 /// We do not provide any a `Span` for the definition and pretty much all other
118 /// queries also ICE when using this `DefId`. Given that the `DefId` of such
119 /// constants should only be reachable by iterating all definitions of a
120 /// given crate, you should not have to worry about this.
121 AnonConst,
122 /// An inline constant, e.g. `const { 1 + 2 }`
123 InlineConst,
124 /// Opaque type, aka `impl Trait`.
125 OpaqueTy,
126 /// A field in a struct, enum or union. e.g.
127 /// - `bar` in `struct Foo { bar: u8 }`
128 /// - `Foo::Bar::0` in `enum Foo { Bar(u8) }`
129 Field,
130 /// Lifetime parameter: the `'a` in `struct Foo<'a> { ... }`
131 LifetimeParam,
132 /// A use of `global_asm!`.
133 GlobalAsm,
134 Impl {
135 of_trait: bool,
136 },
137 /// A closure, coroutine, or coroutine-closure.
138 ///
139 /// These are all represented with the same `ExprKind::Closure` in the AST and HIR,
140 /// which makes it difficult to distinguish these during def collection. Therefore,
141 /// we treat them all the same, and code which needs to distinguish them can match
142 /// or `hir::ClosureKind` or `type_of`.
143 Closure,
144 /// The definition of a synthetic coroutine body created by the lowering of a
145 /// coroutine-closure, such as an async closure.
146 SyntheticCoroutineBody,
147}
148
149impl DefKind {
150 /// Get an English description for the item's kind.
151 ///
152 /// If you have access to `TyCtxt`, use `TyCtxt::def_descr` or
153 /// `TyCtxt::def_kind_descr` instead, because they give better
154 /// information for coroutines and associated functions.
155 pub fn descr(self, def_id: DefId) -> &'static str {
156 match self {
157 DefKind::Fn => "function",
158 DefKind::Mod if def_id.is_crate_root() && !def_id.is_local() => "crate",
159 DefKind::Mod => "module",
160 DefKind::Static { .. } => "static",
161 DefKind::Enum => "enum",
162 DefKind::Variant => "variant",
163 DefKind::Ctor(CtorOf::Variant, CtorKind::Fn) => "tuple variant",
164 DefKind::Ctor(CtorOf::Variant, CtorKind::Const) => "unit variant",
165 DefKind::Struct => "struct",
166 DefKind::Ctor(CtorOf::Struct, CtorKind::Fn) => "tuple struct",
167 DefKind::Ctor(CtorOf::Struct, CtorKind::Const) => "unit struct",
168 DefKind::OpaqueTy => "opaque type",
169 DefKind::TyAlias => "type alias",
170 DefKind::TraitAlias => "trait alias",
171 DefKind::AssocTy => "associated type",
172 DefKind::Union => "union",
173 DefKind::Trait => "trait",
174 DefKind::ForeignTy => "foreign type",
175 DefKind::AssocFn => "associated function",
176 DefKind::Const => "constant",
177 DefKind::AssocConst => "associated constant",
178 DefKind::TyParam => "type parameter",
179 DefKind::ConstParam => "const parameter",
180 DefKind::Macro(macro_kind) => macro_kind.descr(),
181 DefKind::LifetimeParam => "lifetime parameter",
182 DefKind::Use => "import",
183 DefKind::ForeignMod => "foreign module",
184 DefKind::AnonConst => "constant expression",
185 DefKind::InlineConst => "inline constant",
186 DefKind::Field => "field",
187 DefKind::Impl { .. } => "implementation",
188 DefKind::Closure => "closure",
189 DefKind::ExternCrate => "extern crate",
190 DefKind::GlobalAsm => "global assembly block",
191 DefKind::SyntheticCoroutineBody => "synthetic mir body",
192 }
193 }
194
195 /// Gets an English article for the definition.
196 ///
197 /// If you have access to `TyCtxt`, use `TyCtxt::def_descr_article` or
198 /// `TyCtxt::def_kind_descr_article` instead, because they give better
199 /// information for coroutines and associated functions.
200 pub fn article(&self) -> &'static str {
201 match *self {
202 DefKind::AssocTy
203 | DefKind::AssocConst
204 | DefKind::AssocFn
205 | DefKind::Enum
206 | DefKind::OpaqueTy
207 | DefKind::Impl { .. }
208 | DefKind::Use
209 | DefKind::InlineConst
210 | DefKind::ExternCrate => "an",
211 DefKind::Macro(macro_kind) => macro_kind.article(),
212 _ => "a",
213 }
214 }
215
216 pub fn ns(&self) -> Option<Namespace> {
217 match self {
218 DefKind::Mod
219 | DefKind::Struct
220 | DefKind::Union
221 | DefKind::Enum
222 | DefKind::Variant
223 | DefKind::Trait
224 | DefKind::TyAlias
225 | DefKind::ForeignTy
226 | DefKind::TraitAlias
227 | DefKind::AssocTy
228 | DefKind::TyParam => Some(Namespace::TypeNS),
229
230 DefKind::Fn
231 | DefKind::Const
232 | DefKind::ConstParam
233 | DefKind::Static { .. }
234 | DefKind::Ctor(..)
235 | DefKind::AssocFn
236 | DefKind::AssocConst => Some(Namespace::ValueNS),
237
238 DefKind::Macro(..) => Some(Namespace::MacroNS),
239
240 // Not namespaced.
241 DefKind::AnonConst
242 | DefKind::InlineConst
243 | DefKind::Field
244 | DefKind::LifetimeParam
245 | DefKind::ExternCrate
246 | DefKind::Closure
247 | DefKind::Use
248 | DefKind::ForeignMod
249 | DefKind::GlobalAsm
250 | DefKind::Impl { .. }
251 | DefKind::OpaqueTy
252 | DefKind::SyntheticCoroutineBody => None,
253 }
254 }
255
256 // Some `DefKind`s require a name, some don't. Panics if one is needed but
257 // not provided. (`AssocTy` is an exception, see below.)
258 pub fn def_path_data(self, name: Option<Symbol>) -> DefPathData {
259 match self {
260 DefKind::Mod
261 | DefKind::Struct
262 | DefKind::Union
263 | DefKind::Enum
264 | DefKind::Variant
265 | DefKind::Trait
266 | DefKind::TyAlias
267 | DefKind::ForeignTy
268 | DefKind::TraitAlias
269 | DefKind::TyParam
270 | DefKind::ExternCrate => DefPathData::TypeNs(name.unwrap()),
271
272 // An associated type name will be missing for an RPITIT.
273 DefKind::AssocTy => {
274 if let Some(name) = name {
275 DefPathData::TypeNs(name)
276 } else {
277 DefPathData::AnonAssocTy
278 }
279 }
280
281 // It's not exactly an anon const, but wrt DefPathData, there
282 // is no difference.
283 DefKind::Static { nested: true, .. } => DefPathData::AnonConst,
284 DefKind::Fn
285 | DefKind::Const
286 | DefKind::ConstParam
287 | DefKind::Static { .. }
288 | DefKind::AssocFn
289 | DefKind::AssocConst
290 | DefKind::Field => DefPathData::ValueNs(name.unwrap()),
291 DefKind::Macro(..) => DefPathData::MacroNs(name.unwrap()),
292 DefKind::LifetimeParam => DefPathData::LifetimeNs(name.unwrap()),
293 DefKind::Ctor(..) => DefPathData::Ctor,
294 DefKind::Use => DefPathData::Use,
295 DefKind::ForeignMod => DefPathData::ForeignMod,
296 DefKind::AnonConst => DefPathData::AnonConst,
297 DefKind::InlineConst => DefPathData::AnonConst,
298 DefKind::OpaqueTy => DefPathData::OpaqueTy,
299 DefKind::GlobalAsm => DefPathData::GlobalAsm,
300 DefKind::Impl { .. } => DefPathData::Impl,
301 DefKind::Closure => DefPathData::Closure,
302 DefKind::SyntheticCoroutineBody => DefPathData::SyntheticCoroutineBody,
303 }
304 }
305
306 #[inline]
307 pub fn is_fn_like(self) -> bool {
308 matches!(
309 self,
310 DefKind::Fn | DefKind::AssocFn | DefKind::Closure | DefKind::SyntheticCoroutineBody
311 )
312 }
313
314 /// Whether `query get_codegen_attrs` should be used with this definition.
315 pub fn has_codegen_attrs(self) -> bool {
316 match self {
317 DefKind::Fn
318 | DefKind::AssocFn
319 | DefKind::Ctor(..)
320 | DefKind::Closure
321 | DefKind::Static { .. }
322 | DefKind::SyntheticCoroutineBody => true,
323 DefKind::Mod
324 | DefKind::Struct
325 | DefKind::Union
326 | DefKind::Enum
327 | DefKind::Variant
328 | DefKind::Trait
329 | DefKind::TyAlias
330 | DefKind::ForeignTy
331 | DefKind::TraitAlias
332 | DefKind::AssocTy
333 | DefKind::Const
334 | DefKind::AssocConst
335 | DefKind::Macro(..)
336 | DefKind::Use
337 | DefKind::ForeignMod
338 | DefKind::OpaqueTy
339 | DefKind::Impl { .. }
340 | DefKind::Field
341 | DefKind::TyParam
342 | DefKind::ConstParam
343 | DefKind::LifetimeParam
344 | DefKind::AnonConst
345 | DefKind::InlineConst
346 | DefKind::GlobalAsm
347 | DefKind::ExternCrate => false,
348 }
349 }
350}
351
352/// The resolution of a path or export.
353///
354/// For every path or identifier in Rust, the compiler must determine
355/// what the path refers to. This process is called name resolution,
356/// and `Res` is the primary result of name resolution.
357///
358/// For example, everything prefixed with `/* Res */` in this example has
359/// an associated `Res`:
360///
361/// ```
362/// fn str_to_string(s: & /* Res */ str) -> /* Res */ String {
363/// /* Res */ String::from(/* Res */ s)
364/// }
365///
366/// /* Res */ str_to_string("hello");
367/// ```
368///
369/// The associated `Res`s will be:
370///
371/// - `str` will resolve to [`Res::PrimTy`];
372/// - `String` will resolve to [`Res::Def`], and the `Res` will include the [`DefId`]
373/// for `String` as defined in the standard library;
374/// - `String::from` will also resolve to [`Res::Def`], with the [`DefId`]
375/// pointing to `String::from`;
376/// - `s` will resolve to [`Res::Local`];
377/// - the call to `str_to_string` will resolve to [`Res::Def`], with the [`DefId`]
378/// pointing to the definition of `str_to_string` in the current crate.
379//
380#[derive(Clone, Copy, PartialEq, Eq, Encodable, Decodable, Hash, Debug, HashStable_Generic)]
381pub enum Res<Id = hir::HirId> {
382 /// Definition having a unique ID (`DefId`), corresponds to something defined in user code.
383 ///
384 /// **Not bound to a specific namespace.**
385 Def(DefKind, DefId),
386
387 // Type namespace
388 /// A primitive type such as `i32` or `str`.
389 ///
390 /// **Belongs to the type namespace.**
391 PrimTy(hir::PrimTy),
392
393 /// The `Self` type, as used within a trait.
394 ///
395 /// **Belongs to the type namespace.**
396 ///
397 /// See the examples on [`Res::SelfTyAlias`] for details.
398 SelfTyParam {
399 /// The trait this `Self` is a generic parameter for.
400 trait_: DefId,
401 },
402
403 /// The `Self` type, as used somewhere other than within a trait.
404 ///
405 /// **Belongs to the type namespace.**
406 ///
407 /// Examples:
408 /// ```
409 /// struct Bar(Box<Self>); // SelfTyAlias
410 ///
411 /// trait Foo {
412 /// fn foo() -> Box<Self>; // SelfTyParam
413 /// }
414 ///
415 /// impl Bar {
416 /// fn blah() {
417 /// let _: Self; // SelfTyAlias
418 /// }
419 /// }
420 ///
421 /// impl Foo for Bar {
422 /// fn foo() -> Box<Self> { // SelfTyAlias
423 /// let _: Self; // SelfTyAlias
424 ///
425 /// todo!()
426 /// }
427 /// }
428 /// ```
429 /// *See also [`Res::SelfCtor`].*
430 ///
431 SelfTyAlias {
432 /// The item introducing the `Self` type alias. Can be used in the `type_of` query
433 /// to get the underlying type.
434 alias_to: DefId,
435
436 /// Whether the `Self` type is disallowed from mentioning generics (i.e. when used in an
437 /// anonymous constant).
438 ///
439 /// HACK(min_const_generics): self types also have an optional requirement to **not**
440 /// mention any generic parameters to allow the following with `min_const_generics`:
441 /// ```
442 /// # struct Foo;
443 /// impl Foo { fn test() -> [u8; size_of::<Self>()] { todo!() } }
444 ///
445 /// struct Bar([u8; baz::<Self>()]);
446 /// const fn baz<T>() -> usize { 10 }
447 /// ```
448 /// We do however allow `Self` in repeat expression even if it is generic to not break code
449 /// which already works on stable while causing the `const_evaluatable_unchecked` future
450 /// compat lint:
451 /// ```
452 /// fn foo<T>() {
453 /// let _bar = [1_u8; size_of::<*mut T>()];
454 /// }
455 /// ```
456 // FIXME(generic_const_exprs): Remove this bodge once that feature is stable.
457 forbid_generic: bool,
458
459 /// Is this within an `impl Foo for bar`?
460 is_trait_impl: bool,
461 },
462
463 // Value namespace
464 /// The `Self` constructor, along with the [`DefId`]
465 /// of the impl it is associated with.
466 ///
467 /// **Belongs to the value namespace.**
468 ///
469 /// *See also [`Res::SelfTyParam`] and [`Res::SelfTyAlias`].*
470 SelfCtor(DefId),
471
472 /// A local variable or function parameter.
473 ///
474 /// **Belongs to the value namespace.**
475 Local(Id),
476
477 /// A tool attribute module; e.g., the `rustfmt` in `#[rustfmt::skip]`.
478 ///
479 /// **Belongs to the type namespace.**
480 ToolMod,
481
482 // Macro namespace
483 /// An attribute that is *not* implemented via macro.
484 /// E.g., `#[inline]` and `#[rustfmt::skip]`, which are essentially directives,
485 /// as opposed to `#[test]`, which is a builtin macro.
486 ///
487 /// **Belongs to the macro namespace.**
488 NonMacroAttr(NonMacroAttrKind), // e.g., `#[inline]` or `#[rustfmt::skip]`
489
490 // All namespaces
491 /// Name resolution failed. We use a dummy `Res` variant so later phases
492 /// of the compiler won't crash and can instead report more errors.
493 ///
494 /// **Not bound to a specific namespace.**
495 Err,
496}
497
498/// The result of resolving a path before lowering to HIR,
499/// with "module" segments resolved and associated item
500/// segments deferred to type checking.
501/// `base_res` is the resolution of the resolved part of the
502/// path, `unresolved_segments` is the number of unresolved
503/// segments.
504///
505/// ```text
506/// module::Type::AssocX::AssocY::MethodOrAssocType
507/// ^~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
508/// base_res unresolved_segments = 3
509///
510/// <T as Trait>::AssocX::AssocY::MethodOrAssocType
511/// ^~~~~~~~~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~
512/// base_res unresolved_segments = 2
513/// ```
514#[derive(Copy, Clone, Debug)]
515pub struct PartialRes {
516 base_res: Res<NodeId>,
517 unresolved_segments: usize,
518}
519
520impl PartialRes {
521 #[inline]
522 pub fn new(base_res: Res<NodeId>) -> Self {
523 PartialRes { base_res, unresolved_segments: 0 }
524 }
525
526 #[inline]
527 pub fn with_unresolved_segments(base_res: Res<NodeId>, mut unresolved_segments: usize) -> Self {
528 if base_res == Res::Err {
529 unresolved_segments = 0
530 }
531 PartialRes { base_res, unresolved_segments }
532 }
533
534 #[inline]
535 pub fn base_res(&self) -> Res<NodeId> {
536 self.base_res
537 }
538
539 #[inline]
540 pub fn unresolved_segments(&self) -> usize {
541 self.unresolved_segments
542 }
543
544 #[inline]
545 pub fn full_res(&self) -> Option<Res<NodeId>> {
546 (self.unresolved_segments == 0).then_some(self.base_res)
547 }
548
549 #[inline]
550 pub fn expect_full_res(&self) -> Res<NodeId> {
551 self.full_res().expect("unexpected unresolved segments")
552 }
553}
554
555/// Different kinds of symbols can coexist even if they share the same textual name.
556/// Therefore, they each have a separate universe (known as a "namespace").
557#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Encodable, Decodable)]
558#[derive(HashStable_Generic)]
559pub enum Namespace {
560 /// The type namespace includes `struct`s, `enum`s, `union`s, `trait`s, and `mod`s
561 /// (and, by extension, crates).
562 ///
563 /// Note that the type namespace includes other items; this is not an
564 /// exhaustive list.
565 TypeNS,
566 /// The value namespace includes `fn`s, `const`s, `static`s, and local variables (including function arguments).
567 ValueNS,
568 /// The macro namespace includes `macro_rules!` macros, declarative `macro`s,
569 /// procedural macros, attribute macros, `derive` macros, and non-macro attributes
570 /// like `#[inline]` and `#[rustfmt::skip]`.
571 MacroNS,
572}
573
574impl Namespace {
575 /// The English description of the namespace.
576 pub fn descr(self) -> &'static str {
577 match self {
578 Self::TypeNS => "type",
579 Self::ValueNS => "value",
580 Self::MacroNS => "macro",
581 }
582 }
583}
584
585impl<CTX: crate::HashStableContext> ToStableHashKey<CTX> for Namespace {
586 type KeyType = Namespace;
587
588 #[inline]
589 fn to_stable_hash_key(&self, _: &CTX) -> Namespace {
590 *self
591 }
592}
593
594/// Just a helper ‒ separate structure for each namespace.
595#[derive(Copy, Clone, Default, Debug)]
596pub struct PerNS<T> {
597 pub value_ns: T,
598 pub type_ns: T,
599 pub macro_ns: T,
600}
601
602impl<T> PerNS<T> {
603 pub fn map<U, F: FnMut(T) -> U>(self, mut f: F) -> PerNS<U> {
604 PerNS { value_ns: f(self.value_ns), type_ns: f(self.type_ns), macro_ns: f(self.macro_ns) }
605 }
606
607 pub fn into_iter(self) -> IntoIter<T, 3> {
608 [self.value_ns, self.type_ns, self.macro_ns].into_iter()
609 }
610
611 pub fn iter(&self) -> IntoIter<&T, 3> {
612 [&self.value_ns, &self.type_ns, &self.macro_ns].into_iter()
613 }
614}
615
616impl<T> ::std::ops::Index<Namespace> for PerNS<T> {
617 type Output = T;
618
619 fn index(&self, ns: Namespace) -> &T {
620 match ns {
621 Namespace::ValueNS => &self.value_ns,
622 Namespace::TypeNS => &self.type_ns,
623 Namespace::MacroNS => &self.macro_ns,
624 }
625 }
626}
627
628impl<T> ::std::ops::IndexMut<Namespace> for PerNS<T> {
629 fn index_mut(&mut self, ns: Namespace) -> &mut T {
630 match ns {
631 Namespace::ValueNS => &mut self.value_ns,
632 Namespace::TypeNS => &mut self.type_ns,
633 Namespace::MacroNS => &mut self.macro_ns,
634 }
635 }
636}
637
638impl<T> PerNS<Option<T>> {
639 /// Returns `true` if all the items in this collection are `None`.
640 pub fn is_empty(&self) -> bool {
641 self.type_ns.is_none() && self.value_ns.is_none() && self.macro_ns.is_none()
642 }
643
644 /// Returns an iterator over the items which are `Some`.
645 pub fn present_items(self) -> impl Iterator<Item = T> {
646 [self.type_ns, self.value_ns, self.macro_ns].into_iter().flatten()
647 }
648}
649
650impl CtorKind {
651 pub fn from_ast(vdata: &ast::VariantData) -> Option<(CtorKind, NodeId)> {
652 match *vdata {
653 ast::VariantData::Tuple(_, node_id) => Some((CtorKind::Fn, node_id)),
654 ast::VariantData::Unit(node_id) => Some((CtorKind::Const, node_id)),
655 ast::VariantData::Struct { .. } => None,
656 }
657 }
658}
659
660impl NonMacroAttrKind {
661 pub fn descr(self) -> &'static str {
662 match self {
663 NonMacroAttrKind::Builtin(..) => "built-in attribute",
664 NonMacroAttrKind::Tool => "tool attribute",
665 NonMacroAttrKind::DeriveHelper | NonMacroAttrKind::DeriveHelperCompat => {
666 "derive helper attribute"
667 }
668 }
669 }
670
671 // Currently trivial, but exists in case a new kind is added in the future whose name starts
672 // with a vowel.
673 pub fn article(self) -> &'static str {
674 "a"
675 }
676
677 /// Users of some attributes cannot mark them as used, so they are considered always used.
678 pub fn is_used(self) -> bool {
679 match self {
680 NonMacroAttrKind::Tool
681 | NonMacroAttrKind::DeriveHelper
682 | NonMacroAttrKind::DeriveHelperCompat => true,
683 NonMacroAttrKind::Builtin(..) => false,
684 }
685 }
686}
687
688impl<Id> Res<Id> {
689 /// Return the `DefId` of this `Def` if it has an ID, else panic.
690 pub fn def_id(&self) -> DefId
691 where
692 Id: Debug,
693 {
694 self.opt_def_id().unwrap_or_else(|| panic!("attempted .def_id() on invalid res: {self:?}"))
695 }
696
697 /// Return `Some(..)` with the `DefId` of this `Res` if it has a ID, else `None`.
698 pub fn opt_def_id(&self) -> Option<DefId> {
699 match *self {
700 Res::Def(_, id) => Some(id),
701
702 Res::Local(..)
703 | Res::PrimTy(..)
704 | Res::SelfTyParam { .. }
705 | Res::SelfTyAlias { .. }
706 | Res::SelfCtor(..)
707 | Res::ToolMod
708 | Res::NonMacroAttr(..)
709 | Res::Err => None,
710 }
711 }
712
713 /// Return the `DefId` of this `Res` if it represents a module.
714 pub fn mod_def_id(&self) -> Option<DefId> {
715 match *self {
716 Res::Def(DefKind::Mod, id) => Some(id),
717 _ => None,
718 }
719 }
720
721 /// A human readable name for the res kind ("function", "module", etc.).
722 pub fn descr(&self) -> &'static str {
723 match *self {
724 Res::Def(kind, def_id) => kind.descr(def_id),
725 Res::SelfCtor(..) => "self constructor",
726 Res::PrimTy(..) => "builtin type",
727 Res::Local(..) => "local variable",
728 Res::SelfTyParam { .. } | Res::SelfTyAlias { .. } => "self type",
729 Res::ToolMod => "tool module",
730 Res::NonMacroAttr(attr_kind) => attr_kind.descr(),
731 Res::Err => "unresolved item",
732 }
733 }
734
735 /// Gets an English article for the `Res`.
736 pub fn article(&self) -> &'static str {
737 match *self {
738 Res::Def(kind, _) => kind.article(),
739 Res::NonMacroAttr(kind) => kind.article(),
740 Res::Err => "an",
741 _ => "a",
742 }
743 }
744
745 pub fn map_id<R>(self, mut map: impl FnMut(Id) -> R) -> Res<R> {
746 match self {
747 Res::Def(kind, id) => Res::Def(kind, id),
748 Res::SelfCtor(id) => Res::SelfCtor(id),
749 Res::PrimTy(id) => Res::PrimTy(id),
750 Res::Local(id) => Res::Local(map(id)),
751 Res::SelfTyParam { trait_ } => Res::SelfTyParam { trait_ },
752 Res::SelfTyAlias { alias_to, forbid_generic, is_trait_impl } => {
753 Res::SelfTyAlias { alias_to, forbid_generic, is_trait_impl }
754 }
755 Res::ToolMod => Res::ToolMod,
756 Res::NonMacroAttr(attr_kind) => Res::NonMacroAttr(attr_kind),
757 Res::Err => Res::Err,
758 }
759 }
760
761 pub fn apply_id<R, E>(self, mut map: impl FnMut(Id) -> Result<R, E>) -> Result<Res<R>, E> {
762 Ok(match self {
763 Res::Def(kind, id) => Res::Def(kind, id),
764 Res::SelfCtor(id) => Res::SelfCtor(id),
765 Res::PrimTy(id) => Res::PrimTy(id),
766 Res::Local(id) => Res::Local(map(id)?),
767 Res::SelfTyParam { trait_ } => Res::SelfTyParam { trait_ },
768 Res::SelfTyAlias { alias_to, forbid_generic, is_trait_impl } => {
769 Res::SelfTyAlias { alias_to, forbid_generic, is_trait_impl }
770 }
771 Res::ToolMod => Res::ToolMod,
772 Res::NonMacroAttr(attr_kind) => Res::NonMacroAttr(attr_kind),
773 Res::Err => Res::Err,
774 })
775 }
776
777 #[track_caller]
778 pub fn expect_non_local<OtherId>(self) -> Res<OtherId> {
779 self.map_id(
780 #[track_caller]
781 |_| panic!("unexpected `Res::Local`"),
782 )
783 }
784
785 pub fn macro_kind(self) -> Option<MacroKind> {
786 match self {
787 Res::Def(DefKind::Macro(kind), _) => Some(kind),
788 Res::NonMacroAttr(..) => Some(MacroKind::Attr),
789 _ => None,
790 }
791 }
792
793 /// Returns `None` if this is `Res::Err`
794 pub fn ns(&self) -> Option<Namespace> {
795 match self {
796 Res::Def(kind, ..) => kind.ns(),
797 Res::PrimTy(..) | Res::SelfTyParam { .. } | Res::SelfTyAlias { .. } | Res::ToolMod => {
798 Some(Namespace::TypeNS)
799 }
800 Res::SelfCtor(..) | Res::Local(..) => Some(Namespace::ValueNS),
801 Res::NonMacroAttr(..) => Some(Namespace::MacroNS),
802 Res::Err => None,
803 }
804 }
805
806 /// Always returns `true` if `self` is `Res::Err`
807 pub fn matches_ns(&self, ns: Namespace) -> bool {
808 self.ns().is_none_or(|actual_ns| actual_ns == ns)
809 }
810
811 /// Returns whether such a resolved path can occur in a tuple struct/variant pattern
812 pub fn expected_in_tuple_struct_pat(&self) -> bool {
813 matches!(self, Res::Def(DefKind::Ctor(_, CtorKind::Fn), _) | Res::SelfCtor(..))
814 }
815
816 /// Returns whether such a resolved path can occur in a unit struct/variant pattern
817 pub fn expected_in_unit_struct_pat(&self) -> bool {
818 matches!(self, Res::Def(DefKind::Ctor(_, CtorKind::Const), _) | Res::SelfCtor(..))
819 }
820}
821
822/// Resolution for a lifetime appearing in a type.
823#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
824pub enum LifetimeRes {
825 /// Successfully linked the lifetime to a generic parameter.
826 Param {
827 /// Id of the generic parameter that introduced it.
828 param: LocalDefId,
829 /// Id of the introducing place. That can be:
830 /// - an item's id, for the item's generic parameters;
831 /// - a TraitRef's ref_id, identifying the `for<...>` binder;
832 /// - a BareFn type's id.
833 ///
834 /// This information is used for impl-trait lifetime captures, to know when to or not to
835 /// capture any given lifetime.
836 binder: NodeId,
837 },
838 /// Created a generic parameter for an anonymous lifetime.
839 Fresh {
840 /// Id of the generic parameter that introduced it.
841 ///
842 /// Creating the associated `LocalDefId` is the responsibility of lowering.
843 param: NodeId,
844 /// Id of the introducing place. See `Param`.
845 binder: NodeId,
846 /// Kind of elided lifetime
847 kind: hir::MissingLifetimeKind,
848 },
849 /// This variant is used for anonymous lifetimes that we did not resolve during
850 /// late resolution. Those lifetimes will be inferred by typechecking.
851 Infer,
852 /// `'static` lifetime.
853 Static {
854 /// We do not want to emit `elided_named_lifetimes`
855 /// when we are inside of a const item or a static,
856 /// because it would get too annoying.
857 suppress_elision_warning: bool,
858 },
859 /// Resolution failure.
860 Error,
861 /// HACK: This is used to recover the NodeId of an elided lifetime.
862 ElidedAnchor { start: NodeId, end: NodeId },
863}
864
865pub type DocLinkResMap = UnordMap<(Symbol, Namespace), Option<Res<NodeId>>>;