rustdoc_json_types/
lib.rs

1//! Rustdoc's JSON output interface
2//!
3//! These types are the public API exposed through the `--output-format json` flag. The [`Crate`]
4//! struct is the root of the JSON blob and all other items are contained within.
5//!
6//! We expose a `rustc-hash` feature that is disabled by default. This feature switches the
7//! [`std::collections::HashMap`] for [`rustc_hash::FxHashMap`] to improve the performance of said
8//! `HashMap` in specific situations.
9//!
10//! `cargo-semver-checks` for example, saw a [-3% improvement][1] when benchmarking using the
11//! `aws_sdk_ec2` JSON output (~500MB of JSON). As always, we recommend measuring the impact before
12//! turning this feature on, as [`FxHashMap`][2] only concerns itself with hash speed, and may
13//! increase the number of collisions.
14//!
15//! [1]: https://rust-lang.zulipchat.com/#narrow/channel/266220-t-rustdoc/topic/rustc-hash.20and.20performance.20of.20rustdoc-types/near/474855731
16//! [2]: https://crates.io/crates/rustc-hash
17
18#[cfg(not(feature = "rustc-hash"))]
19use std::collections::HashMap;
20use std::path::PathBuf;
21
22#[cfg(feature = "rustc-hash")]
23use rustc_hash::FxHashMap as HashMap;
24use serde::{Deserialize, Serialize};
25
26pub type FxHashMap<K, V> = HashMap<K, V>; // re-export for use in src/librustdoc
27
28/// The version of JSON output that this crate represents.
29///
30/// This integer is incremented with every breaking change to the API,
31/// and is returned along with the JSON blob as [`Crate::format_version`].
32/// Consuming code should assert that this value matches the format version(s) that it supports.
33pub const FORMAT_VERSION: u32 = 45;
34
35/// The root of the emitted JSON blob.
36///
37/// It contains all type/documentation information
38/// about the language items in the local crate, as well as info about external items to allow
39/// tools to find or link to them.
40#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
41pub struct Crate {
42    /// The id of the root [`Module`] item of the local crate.
43    pub root: Id,
44    /// The version string given to `--crate-version`, if any.
45    pub crate_version: Option<String>,
46    /// Whether or not the output includes private items.
47    pub includes_private: bool,
48    /// A collection of all items in the local crate as well as some external traits and their
49    /// items that are referenced locally.
50    pub index: HashMap<Id, Item>,
51    /// Maps IDs to fully qualified paths and other info helpful for generating links.
52    pub paths: HashMap<Id, ItemSummary>,
53    /// Maps `crate_id` of items to a crate name and html_root_url if it exists.
54    pub external_crates: HashMap<u32, ExternalCrate>,
55    /// Information about the target for which this documentation was generated
56    pub target: Target,
57    /// A single version number to be used in the future when making backwards incompatible changes
58    /// to the JSON output.
59    pub format_version: u32,
60}
61
62/// Information about a target
63#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
64pub struct Target {
65    /// The target triple for which this documentation was generated
66    pub triple: String,
67    /// A list of features valid for use in `#[target_feature]` attributes
68    /// for the target where this rustdoc JSON was generated.
69    pub target_features: Vec<TargetFeature>,
70}
71
72/// Information about a target feature.
73///
74/// Rust target features are used to influence code generation, especially around selecting
75/// instructions which are not universally supported by the target architecture.
76///
77/// Target features are commonly enabled by the [`#[target_feature]` attribute][1] to influence code
78/// generation for a particular function, and less commonly enabled by compiler options like
79/// `-Ctarget-feature` or `-Ctarget-cpu`. Targets themselves automatically enable certain target
80/// features by default, for example because the target's ABI specification requires saving specific
81/// registers which only exist in an architectural extension.
82///
83/// Target features can imply other target features: for example, x86-64 `avx2` implies `avx`, and
84/// aarch64 `sve2` implies `sve`, since both of these architectural extensions depend on their
85/// predecessors.
86///
87/// Target features can be probed at compile time by [`#[cfg(target_feature)]`][2] or `cfg!(…)`
88/// conditional compilation to determine whether a target feature is enabled in a particular
89/// context.
90///
91/// [1]: https://doc.rust-lang.org/stable/reference/attributes/codegen.html#the-target_feature-attribute
92/// [2]: https://doc.rust-lang.org/reference/conditional-compilation.html#target_feature
93#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
94pub struct TargetFeature {
95    /// The name of this target feature.
96    pub name: String,
97    /// Other target features which are implied by this target feature, if any.
98    pub implies_features: Vec<String>,
99    /// If this target feature is unstable, the name of the associated language feature gate.
100    pub unstable_feature_gate: Option<String>,
101    /// Whether this feature is globally enabled for this compilation session.
102    ///
103    /// Target features can be globally enabled implicitly as a result of the target's definition.
104    /// For example, x86-64 hardware floating point ABIs require saving x87 and SSE2 registers,
105    /// which in turn requires globally enabling the `x87` and `sse2` target features so that the
106    /// generated machine code conforms to the target's ABI.
107    ///
108    /// Target features can also be globally enabled explicitly as a result of compiler flags like
109    /// [`-Ctarget-feature`][1] or [`-Ctarget-cpu`][2].
110    ///
111    /// [1]: https://doc.rust-lang.org/beta/rustc/codegen-options/index.html#target-feature
112    /// [2]: https://doc.rust-lang.org/beta/rustc/codegen-options/index.html#target-cpu
113    pub globally_enabled: bool,
114}
115
116/// Metadata of a crate, either the same crate on which `rustdoc` was invoked, or its dependency.
117#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
118pub struct ExternalCrate {
119    /// The name of the crate.
120    ///
121    /// Note: This is the [*crate* name][crate-name], which may not be the same as the
122    /// [*package* name][package-name]. For example, for <https://crates.io/crates/regex-syntax>,
123    /// this field will be `regex_syntax` (which uses an `_`, not a `-`).
124    ///
125    /// [crate-name]: https://doc.rust-lang.org/stable/cargo/reference/cargo-targets.html#the-name-field
126    /// [package-name]: https://doc.rust-lang.org/stable/cargo/reference/manifest.html#the-name-field
127    pub name: String,
128    /// The root URL at which the crate's documentation lives.
129    pub html_root_url: Option<String>,
130}
131
132/// Information about an external (not defined in the local crate) [`Item`].
133///
134/// For external items, you don't get the same level of
135/// information. This struct should contain enough to generate a link/reference to the item in
136/// question, or can be used by a tool that takes the json output of multiple crates to find
137/// the actual item definition with all the relevant info.
138#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
139pub struct ItemSummary {
140    /// Can be used to look up the name and html_root_url of the crate this item came from in the
141    /// `external_crates` map.
142    pub crate_id: u32,
143    /// The list of path components for the fully qualified path of this item (e.g.
144    /// `["std", "io", "lazy", "Lazy"]` for `std::io::lazy::Lazy`).
145    ///
146    /// Note that items can appear in multiple paths, and the one chosen is implementation
147    /// defined. Currently, this is the full path to where the item was defined. Eg
148    /// [`String`] is currently `["alloc", "string", "String"]` and [`HashMap`][`std::collections::HashMap`]
149    /// is `["std", "collections", "hash", "map", "HashMap"]`, but this is subject to change.
150    pub path: Vec<String>,
151    /// Whether this item is a struct, trait, macro, etc.
152    pub kind: ItemKind,
153}
154
155/// Anything that can hold documentation - modules, structs, enums, functions, traits, etc.
156///
157/// The `Item` data type holds fields that can apply to any of these,
158/// and leaves kind-specific details (like function args or enum variants) to the `inner` field.
159#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
160pub struct Item {
161    /// The unique identifier of this item. Can be used to find this item in various mappings.
162    pub id: Id,
163    /// This can be used as a key to the `external_crates` map of [`Crate`] to see which crate
164    /// this item came from.
165    pub crate_id: u32,
166    /// Some items such as impls don't have names.
167    pub name: Option<String>,
168    /// The source location of this item (absent if it came from a macro expansion or inline
169    /// assembly).
170    pub span: Option<Span>,
171    /// By default all documented items are public, but you can tell rustdoc to output private items
172    /// so this field is needed to differentiate.
173    pub visibility: Visibility,
174    /// The full markdown docstring of this item. Absent if there is no documentation at all,
175    /// Some("") if there is some documentation but it is empty (EG `#[doc = ""]`).
176    pub docs: Option<String>,
177    /// This mapping resolves [intra-doc links](https://github.com/rust-lang/rfcs/blob/master/text/1946-intra-rustdoc-links.md) from the docstring to their IDs
178    pub links: HashMap<String, Id>,
179    /// Attributes on this item.
180    ///
181    /// Does not include `#[deprecated]` attributes: see the [`Self::deprecation`] field instead.
182    ///
183    /// Some attributes appear in pretty-printed Rust form, regardless of their formatting
184    /// in the original source code. For example:
185    /// - `#[non_exhaustive]` and `#[must_use]` are represented as themselves.
186    /// - `#[no_mangle]` and `#[export_name]` are also represented as themselves.
187    /// - `#[repr(C)]` and other reprs also appear as themselves,
188    ///   though potentially with a different order: e.g. `repr(i8, C)` may become `repr(C, i8)`.
189    ///   Multiple repr attributes on the same item may be combined into an equivalent single attr.
190    ///
191    /// Other attributes may appear debug-printed. For example:
192    /// - `#[inline]` becomes something similar to `#[attr="Inline(Hint)"]`.
193    ///
194    /// As an internal implementation detail subject to change, this debug-printing format
195    /// is currently equivalent to the HIR pretty-printing of parsed attributes.
196    pub attrs: Vec<String>,
197    /// Information about the item’s deprecation, if present.
198    pub deprecation: Option<Deprecation>,
199    /// The type-specific fields describing this item.
200    pub inner: ItemEnum,
201}
202
203/// A range of source code.
204#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
205pub struct Span {
206    /// The path to the source file for this span relative to the path `rustdoc` was invoked with.
207    pub filename: PathBuf,
208    /// One indexed Line and Column of the first character of the `Span`.
209    pub begin: (usize, usize),
210    /// One indexed Line and Column of the last character of the `Span`.
211    pub end: (usize, usize),
212}
213
214/// Information about the deprecation of an [`Item`].
215#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
216pub struct Deprecation {
217    /// Usually a version number when this [`Item`] first became deprecated.
218    pub since: Option<String>,
219    /// The reason for deprecation and/or what alternatives to use.
220    pub note: Option<String>,
221}
222
223/// Visibility of an [`Item`].
224#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
225#[serde(rename_all = "snake_case")]
226pub enum Visibility {
227    /// Explicitly public visibility set with `pub`.
228    Public,
229    /// For the most part items are private by default. The exceptions are associated items of
230    /// public traits and variants of public enums.
231    Default,
232    /// Explicitly crate-wide visibility set with `pub(crate)`
233    Crate,
234    /// For `pub(in path)` visibility.
235    Restricted {
236        /// ID of the module to which this visibility restricts items.
237        parent: Id,
238        /// The path with which [`parent`] was referenced
239        /// (like `super::super` or `crate::foo::bar`).
240        ///
241        /// [`parent`]: Visibility::Restricted::parent
242        path: String,
243    },
244}
245
246/// Dynamic trait object type (`dyn Trait`).
247#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
248pub struct DynTrait {
249    /// All the traits implemented. One of them is the vtable, and the rest must be auto traits.
250    pub traits: Vec<PolyTrait>,
251    /// The lifetime of the whole dyn object
252    /// ```text
253    /// dyn Debug + 'static
254    ///             ^^^^^^^
255    ///             |
256    ///             this part
257    /// ```
258    pub lifetime: Option<String>,
259}
260
261/// A trait and potential HRTBs
262#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
263pub struct PolyTrait {
264    /// The path to the trait.
265    #[serde(rename = "trait")]
266    pub trait_: Path,
267    /// Used for Higher-Rank Trait Bounds (HRTBs)
268    /// ```text
269    /// dyn for<'a> Fn() -> &'a i32"
270    ///     ^^^^^^^
271    /// ```
272    pub generic_params: Vec<GenericParamDef>,
273}
274
275/// A set of generic arguments provided to a path segment, e.g.
276///
277/// ```text
278/// std::option::Option::<u32>::None
279///                      ^^^^^
280/// ```
281#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
282#[serde(rename_all = "snake_case")]
283pub enum GenericArgs {
284    /// `<'a, 32, B: Copy, C = u32>`
285    AngleBracketed {
286        /// The list of each argument on this type.
287        /// ```text
288        /// <'a, 32, B: Copy, C = u32>
289        ///  ^^^^^^
290        /// ```
291        args: Vec<GenericArg>,
292        /// Associated type or constant bindings (e.g. `Item=i32` or `Item: Clone`) for this type.
293        constraints: Vec<AssocItemConstraint>,
294    },
295    /// `Fn(A, B) -> C`
296    Parenthesized {
297        /// The input types, enclosed in parentheses.
298        inputs: Vec<Type>,
299        /// The output type provided after the `->`, if present.
300        output: Option<Type>,
301    },
302    /// `T::method(..)`
303    ReturnTypeNotation,
304}
305
306/// One argument in a list of generic arguments to a path segment.
307///
308/// Part of [`GenericArgs`].
309#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
310#[serde(rename_all = "snake_case")]
311pub enum GenericArg {
312    /// A lifetime argument.
313    /// ```text
314    /// std::borrow::Cow<'static, str>
315    ///                  ^^^^^^^
316    /// ```
317    Lifetime(String),
318    /// A type argument.
319    /// ```text
320    /// std::borrow::Cow<'static, str>
321    ///                           ^^^
322    /// ```
323    Type(Type),
324    /// A constant as a generic argument.
325    /// ```text
326    /// core::array::IntoIter<u32, { 640 * 1024 }>
327    ///                            ^^^^^^^^^^^^^^
328    /// ```
329    Const(Constant),
330    /// A generic argument that's explicitly set to be inferred.
331    /// ```text
332    /// std::vec::Vec::<_>::new()
333    ///                 ^
334    /// ```
335    Infer,
336}
337
338/// A constant.
339#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
340pub struct Constant {
341    /// The stringified expression of this constant. Note that its mapping to the original
342    /// source code is unstable and it's not guaranteed that it'll match the source code.
343    pub expr: String,
344    /// The value of the evaluated expression for this constant, which is only computed for numeric
345    /// types.
346    pub value: Option<String>,
347    /// Whether this constant is a bool, numeric, string, or char literal.
348    pub is_literal: bool,
349}
350
351/// Describes a bound applied to an associated type/constant.
352///
353/// Example:
354/// ```text
355/// IntoIterator<Item = u32, IntoIter: Clone>
356///              ^^^^^^^^^^  ^^^^^^^^^^^^^^^
357/// ```
358#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
359pub struct AssocItemConstraint {
360    /// The name of the associated type/constant.
361    pub name: String,
362    /// Arguments provided to the associated type/constant.
363    pub args: GenericArgs,
364    /// The kind of bound applied to the associated type/constant.
365    pub binding: AssocItemConstraintKind,
366}
367
368/// The way in which an associate type/constant is bound.
369#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
370#[serde(rename_all = "snake_case")]
371pub enum AssocItemConstraintKind {
372    /// The required value/type is specified exactly. e.g.
373    /// ```text
374    /// Iterator<Item = u32, IntoIter: DoubleEndedIterator>
375    ///          ^^^^^^^^^^
376    /// ```
377    Equality(Term),
378    /// The type is required to satisfy a set of bounds.
379    /// ```text
380    /// Iterator<Item = u32, IntoIter: DoubleEndedIterator>
381    ///                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
382    /// ```
383    Constraint(Vec<GenericBound>),
384}
385
386/// An opaque identifier for an item.
387///
388/// It can be used to lookup in [`Crate::index`] or [`Crate::paths`] to resolve it
389/// to an [`Item`].
390///
391/// Id's are only valid within a single JSON blob. They cannot be used to
392/// resolve references between the JSON output's for different crates.
393///
394/// Rustdoc makes no guarantees about the inner value of Id's. Applications
395/// should treat them as opaque keys to lookup items, and avoid attempting
396/// to parse them, or otherwise depend on any implementation details.
397#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
398// FIXME(aDotInTheVoid): Consider making this non-public in rustdoc-types.
399pub struct Id(pub u32);
400
401/// The fundamental kind of an item. Unlike [`ItemEnum`], this does not carry any additional info.
402///
403/// Part of [`ItemSummary`].
404#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
405#[serde(rename_all = "snake_case")]
406pub enum ItemKind {
407    /// A module declaration, e.g. `mod foo;` or `mod foo {}`
408    Module,
409    /// A crate imported via the `extern crate` syntax.
410    ExternCrate,
411    /// An import of 1 or more items into scope, using the `use` keyword.
412    Use,
413    /// A `struct` declaration.
414    Struct,
415    /// A field of a struct.
416    StructField,
417    /// A `union` declaration.
418    Union,
419    /// An `enum` declaration.
420    Enum,
421    /// A variant of a enum.
422    Variant,
423    /// A function declaration, e.g. `fn f() {}`
424    Function,
425    /// A type alias declaration, e.g. `type Pig = std::borrow::Cow<'static, str>;`
426    TypeAlias,
427    /// The declaration of a constant, e.g. `const GREETING: &str = "Hi :3";`
428    Constant,
429    /// A `trait` declaration.
430    Trait,
431    /// A trait alias declaration, e.g. `trait Int = Add + Sub + Mul + Div;`
432    ///
433    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/41517)
434    TraitAlias,
435    /// An `impl` block.
436    Impl,
437    /// A `static` declaration.
438    Static,
439    /// `type`s from an `extern` block.
440    ///
441    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/43467)
442    ExternType,
443    /// A macro declaration.
444    ///
445    /// Corresponds to either `ItemEnum::Macro(_)`
446    /// or `ItemEnum::ProcMacro(ProcMacro { kind: MacroKind::Bang })`
447    Macro,
448    /// A procedural macro attribute.
449    ///
450    /// Corresponds to `ItemEnum::ProcMacro(ProcMacro { kind: MacroKind::Attr })`
451    ProcAttribute,
452    /// A procedural macro usable in the `#[derive()]` attribute.
453    ///
454    /// Corresponds to `ItemEnum::ProcMacro(ProcMacro { kind: MacroKind::Derive })`
455    ProcDerive,
456    /// An associated constant of a trait or a type.
457    AssocConst,
458    /// An associated type of a trait or a type.
459    AssocType,
460    /// A primitive type, e.g. `u32`.
461    ///
462    /// [`Item`]s of this kind only come from the core library.
463    Primitive,
464    /// A keyword declaration.
465    ///
466    /// [`Item`]s of this kind only come from the come library and exist solely
467    /// to carry documentation for the respective keywords.
468    Keyword,
469}
470
471/// Specific fields of an item.
472///
473/// Part of [`Item`].
474#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
475#[serde(rename_all = "snake_case")]
476pub enum ItemEnum {
477    /// A module declaration, e.g. `mod foo;` or `mod foo {}`
478    Module(Module),
479    /// A crate imported via the `extern crate` syntax.
480    ExternCrate {
481        /// The name of the imported crate.
482        name: String,
483        /// If the crate is renamed, this is its name in the crate.
484        rename: Option<String>,
485    },
486    /// An import of 1 or more items into scope, using the `use` keyword.
487    Use(Use),
488
489    /// A `union` declaration.
490    Union(Union),
491    /// A `struct` declaration.
492    Struct(Struct),
493    /// A field of a struct.
494    StructField(Type),
495    /// An `enum` declaration.
496    Enum(Enum),
497    /// A variant of a enum.
498    Variant(Variant),
499
500    /// A function declaration (including methods and other associated functions)
501    Function(Function),
502
503    /// A `trait` declaration.
504    Trait(Trait),
505    /// A trait alias declaration, e.g. `trait Int = Add + Sub + Mul + Div;`
506    ///
507    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/41517)
508    TraitAlias(TraitAlias),
509    /// An `impl` block.
510    Impl(Impl),
511
512    /// A type alias declaration, e.g. `type Pig = std::borrow::Cow<'static, str>;`
513    TypeAlias(TypeAlias),
514    /// The declaration of a constant, e.g. `const GREETING: &str = "Hi :3";`
515    Constant {
516        /// The type of the constant.
517        #[serde(rename = "type")]
518        type_: Type,
519        /// The declared constant itself.
520        #[serde(rename = "const")]
521        const_: Constant,
522    },
523
524    /// A declaration of a `static`.
525    Static(Static),
526
527    /// `type`s from an `extern` block.
528    ///
529    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/43467)
530    ExternType,
531
532    /// A macro_rules! declarative macro. Contains a single string with the source
533    /// representation of the macro with the patterns stripped.
534    Macro(String),
535    /// A procedural macro.
536    ProcMacro(ProcMacro),
537
538    /// A primitive type, e.g. `u32`.
539    ///
540    /// [`Item`]s of this kind only come from the core library.
541    Primitive(Primitive),
542
543    /// An associated constant of a trait or a type.
544    AssocConst {
545        /// The type of the constant.
546        #[serde(rename = "type")]
547        type_: Type,
548        /// Inside a trait declaration, this is the default value for the associated constant,
549        /// if provided.
550        /// Inside an `impl` block, this is the value assigned to the associated constant,
551        /// and will always be present.
552        ///
553        /// The representation is implementation-defined and not guaranteed to be representative of
554        /// either the resulting value or of the source code.
555        ///
556        /// ```rust
557        /// const X: usize = 640 * 1024;
558        /// //               ^^^^^^^^^^
559        /// ```
560        value: Option<String>,
561    },
562    /// An associated type of a trait or a type.
563    AssocType {
564        /// The generic parameters and where clauses on ahis associated type.
565        generics: Generics,
566        /// The bounds for this associated type. e.g.
567        /// ```rust
568        /// trait IntoIterator {
569        ///     type Item;
570        ///     type IntoIter: Iterator<Item = Self::Item>;
571        /// //                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
572        /// }
573        /// ```
574        bounds: Vec<GenericBound>,
575        /// Inside a trait declaration, this is the default for the associated type, if provided.
576        /// Inside an impl block, this is the type assigned to the associated type, and will always
577        /// be present.
578        ///
579        /// ```rust
580        /// type X = usize;
581        /// //       ^^^^^
582        /// ```
583        #[serde(rename = "type")]
584        type_: Option<Type>,
585    },
586}
587
588/// A module declaration, e.g. `mod foo;` or `mod foo {}`.
589#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
590pub struct Module {
591    /// Whether this is the root item of a crate.
592    ///
593    /// This item doesn't correspond to any construction in the source code and is generated by the
594    /// compiler.
595    pub is_crate: bool,
596    /// [`Item`]s declared inside this module.
597    pub items: Vec<Id>,
598    /// If `true`, this module is not part of the public API, but it contains
599    /// items that are re-exported as public API.
600    pub is_stripped: bool,
601}
602
603/// A `union`.
604#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
605pub struct Union {
606    /// The generic parameters and where clauses on this union.
607    pub generics: Generics,
608    /// Whether any fields have been removed from the result, due to being private or hidden.
609    pub has_stripped_fields: bool,
610    /// The list of fields in the union.
611    ///
612    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::StructField`].
613    pub fields: Vec<Id>,
614    /// All impls (both of traits and inherent) for this union.
615    ///
616    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Impl`].
617    pub impls: Vec<Id>,
618}
619
620/// A `struct`.
621#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
622pub struct Struct {
623    /// The kind of the struct (e.g. unit, tuple-like or struct-like) and the data specific to it,
624    /// i.e. fields.
625    pub kind: StructKind,
626    /// The generic parameters and where clauses on this struct.
627    pub generics: Generics,
628    /// All impls (both of traits and inherent) for this struct.
629    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Impl`].
630    pub impls: Vec<Id>,
631}
632
633/// The kind of a [`Struct`] and the data specific to it, i.e. fields.
634#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
635#[serde(rename_all = "snake_case")]
636pub enum StructKind {
637    /// A struct with no fields and no parentheses.
638    ///
639    /// ```rust
640    /// pub struct Unit;
641    /// ```
642    Unit,
643    /// A struct with unnamed fields.
644    ///
645    /// All [`Id`]'s will point to [`ItemEnum::StructField`].
646    /// Unlike most of JSON, private and `#[doc(hidden)]` fields will be given as `None`
647    /// instead of being omitted, because order matters.
648    ///
649    /// ```rust
650    /// pub struct TupleStruct(i32);
651    /// pub struct EmptyTupleStruct();
652    /// ```
653    Tuple(Vec<Option<Id>>),
654    /// A struct with named fields.
655    ///
656    /// ```rust
657    /// pub struct PlainStruct { x: i32 }
658    /// pub struct EmptyPlainStruct {}
659    /// ```
660    Plain {
661        /// The list of fields in the struct.
662        ///
663        /// All of the corresponding [`Item`]s are of kind [`ItemEnum::StructField`].
664        fields: Vec<Id>,
665        /// Whether any fields have been removed from the result, due to being private or hidden.
666        has_stripped_fields: bool,
667    },
668}
669
670/// An `enum`.
671#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
672pub struct Enum {
673    /// Information about the type parameters and `where` clauses of the enum.
674    pub generics: Generics,
675    /// Whether any variants have been removed from the result, due to being private or hidden.
676    pub has_stripped_variants: bool,
677    /// The list of variants in the enum.
678    ///
679    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Variant`]
680    pub variants: Vec<Id>,
681    /// `impl`s for the enum.
682    pub impls: Vec<Id>,
683}
684
685/// A variant of an enum.
686#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
687pub struct Variant {
688    /// Whether the variant is plain, a tuple-like, or struct-like. Contains the fields.
689    pub kind: VariantKind,
690    /// The discriminant, if explicitly specified.
691    pub discriminant: Option<Discriminant>,
692}
693
694/// The kind of an [`Enum`] [`Variant`] and the data specific to it, i.e. fields.
695#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
696#[serde(rename_all = "snake_case")]
697pub enum VariantKind {
698    /// A variant with no parentheses
699    ///
700    /// ```rust
701    /// enum Demo {
702    ///     PlainVariant,
703    ///     PlainWithDiscriminant = 1,
704    /// }
705    /// ```
706    Plain,
707    /// A variant with unnamed fields.
708    ///
709    /// All [`Id`]'s will point to [`ItemEnum::StructField`].
710    /// Unlike most of JSON, `#[doc(hidden)]` fields will be given as `None`
711    /// instead of being omitted, because order matters.
712    ///
713    /// ```rust
714    /// enum Demo {
715    ///     TupleVariant(i32),
716    ///     EmptyTupleVariant(),
717    /// }
718    /// ```
719    Tuple(Vec<Option<Id>>),
720    /// A variant with named fields.
721    ///
722    /// ```rust
723    /// enum Demo {
724    ///     StructVariant { x: i32 },
725    ///     EmptyStructVariant {},
726    /// }
727    /// ```
728    Struct {
729        /// The list of variants in the enum.
730        /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Variant`].
731        fields: Vec<Id>,
732        /// Whether any variants have been removed from the result, due to being private or hidden.
733        has_stripped_fields: bool,
734    },
735}
736
737/// The value that distinguishes a variant in an [`Enum`] from other variants.
738#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
739pub struct Discriminant {
740    /// The expression that produced the discriminant.
741    ///
742    /// Unlike `value`, this preserves the original formatting (eg suffixes,
743    /// hexadecimal, and underscores), making it unsuitable to be machine
744    /// interpreted.
745    ///
746    /// In some cases, when the value is too complex, this may be `"{ _ }"`.
747    /// When this occurs is unstable, and may change without notice.
748    pub expr: String,
749    /// The numerical value of the discriminant. Stored as a string due to
750    /// JSON's poor support for large integers, and the fact that it would need
751    /// to store from [`i128::MIN`] to [`u128::MAX`].
752    pub value: String,
753}
754
755/// A set of fundamental properties of a function.
756#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
757pub struct FunctionHeader {
758    /// Is this function marked as `const`?
759    pub is_const: bool,
760    /// Is this function unsafe?
761    pub is_unsafe: bool,
762    /// Is this function async?
763    pub is_async: bool,
764    /// The ABI used by the function.
765    pub abi: Abi,
766}
767
768/// The ABI (Application Binary Interface) used by a function.
769///
770/// If a variant has an `unwind` field, this means the ABI that it represents can be specified in 2
771/// ways: `extern "_"` and `extern "_-unwind"`, and a value of `true` for that field signifies the
772/// latter variant.
773///
774/// See the [Rustonomicon section](https://doc.rust-lang.org/nightly/nomicon/ffi.html#ffi-and-unwinding)
775/// on unwinding for more info.
776#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
777pub enum Abi {
778    // We only have a concrete listing here for stable ABI's because there are so many
779    // See rustc_ast_passes::feature_gate::PostExpansionVisitor::check_abi for the list
780    /// The default ABI, but that can also be written explicitly with `extern "Rust"`.
781    Rust,
782    /// Can be specified as `extern "C"` or, as a shorthand, just `extern`.
783    C { unwind: bool },
784    /// Can be specified as `extern "cdecl"`.
785    Cdecl { unwind: bool },
786    /// Can be specified as `extern "stdcall"`.
787    Stdcall { unwind: bool },
788    /// Can be specified as `extern "fastcall"`.
789    Fastcall { unwind: bool },
790    /// Can be specified as `extern "aapcs"`.
791    Aapcs { unwind: bool },
792    /// Can be specified as `extern "win64"`.
793    Win64 { unwind: bool },
794    /// Can be specified as `extern "sysv64"`.
795    SysV64 { unwind: bool },
796    /// Can be specified as `extern "system"`.
797    System { unwind: bool },
798    /// Any other ABI, including unstable ones.
799    Other(String),
800}
801
802/// A function declaration (including methods and other associated functions).
803#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
804pub struct Function {
805    /// Information about the function signature, or declaration.
806    pub sig: FunctionSignature,
807    /// Information about the function’s type parameters and `where` clauses.
808    pub generics: Generics,
809    /// Information about core properties of the function, e.g. whether it's `const`, its ABI, etc.
810    pub header: FunctionHeader,
811    /// Whether the function has a body, i.e. an implementation.
812    pub has_body: bool,
813}
814
815/// Generic parameters accepted by an item and `where` clauses imposed on it and the parameters.
816#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
817pub struct Generics {
818    /// A list of generic parameter definitions (e.g. `<T: Clone + Hash, U: Copy>`).
819    pub params: Vec<GenericParamDef>,
820    /// A list of where predicates (e.g. `where T: Iterator, T::Item: Copy`).
821    pub where_predicates: Vec<WherePredicate>,
822}
823
824/// One generic parameter accepted by an item.
825#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
826pub struct GenericParamDef {
827    /// Name of the parameter.
828    /// ```rust
829    /// fn f<'resource, Resource>(x: &'resource Resource) {}
830    /// //    ^^^^^^^^  ^^^^^^^^
831    /// ```
832    pub name: String,
833    /// The kind of the parameter and data specific to a particular parameter kind, e.g. type
834    /// bounds.
835    pub kind: GenericParamDefKind,
836}
837
838/// The kind of a [`GenericParamDef`].
839#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
840#[serde(rename_all = "snake_case")]
841pub enum GenericParamDefKind {
842    /// Denotes a lifetime parameter.
843    Lifetime {
844        /// Lifetimes that this lifetime parameter is required to outlive.
845        ///
846        /// ```rust
847        /// fn f<'a, 'b, 'resource: 'a + 'b>(a: &'a str, b: &'b str, res: &'resource str) {}
848        /// //                      ^^^^^^^
849        /// ```
850        outlives: Vec<String>,
851    },
852
853    /// Denotes a type parameter.
854    Type {
855        /// Bounds applied directly to the type. Note that the bounds from `where` clauses
856        /// that constrain this parameter won't appear here.
857        ///
858        /// ```rust
859        /// fn default2<T: Default>() -> [T; 2] where T: Clone { todo!() }
860        /// //             ^^^^^^^
861        /// ```
862        bounds: Vec<GenericBound>,
863        /// The default type for this parameter, if provided, e.g.
864        ///
865        /// ```rust
866        /// trait PartialEq<Rhs = Self> {}
867        /// //                    ^^^^
868        /// ```
869        default: Option<Type>,
870        /// This is normally `false`, which means that this generic parameter is
871        /// declared in the Rust source text.
872        ///
873        /// If it is `true`, this generic parameter has been introduced by the
874        /// compiler behind the scenes.
875        ///
876        /// # Example
877        ///
878        /// Consider
879        ///
880        /// ```ignore (pseudo-rust)
881        /// pub fn f(_: impl Trait) {}
882        /// ```
883        ///
884        /// The compiler will transform this behind the scenes to
885        ///
886        /// ```ignore (pseudo-rust)
887        /// pub fn f<impl Trait: Trait>(_: impl Trait) {}
888        /// ```
889        ///
890        /// In this example, the generic parameter named `impl Trait` (and which
891        /// is bound by `Trait`) is synthetic, because it was not originally in
892        /// the Rust source text.
893        is_synthetic: bool,
894    },
895
896    /// Denotes a constant parameter.
897    Const {
898        /// The type of the constant as declared.
899        #[serde(rename = "type")]
900        type_: Type,
901        /// The stringified expression for the default value, if provided. It's not guaranteed that
902        /// it'll match the actual source code for the default value.
903        default: Option<String>,
904    },
905}
906
907/// One `where` clause.
908/// ```rust
909/// fn default<T>() -> T where T: Default { T::default() }
910/// //                         ^^^^^^^^^^
911/// ```
912#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
913#[serde(rename_all = "snake_case")]
914pub enum WherePredicate {
915    /// A type is expected to comply with a set of bounds
916    BoundPredicate {
917        /// The type that's being constrained.
918        ///
919        /// ```rust
920        /// fn f<T>(x: T) where for<'a> &'a T: Iterator {}
921        /// //                              ^
922        /// ```
923        #[serde(rename = "type")]
924        type_: Type,
925        /// The set of bounds that constrain the type.
926        ///
927        /// ```rust
928        /// fn f<T>(x: T) where for<'a> &'a T: Iterator {}
929        /// //                                 ^^^^^^^^
930        /// ```
931        bounds: Vec<GenericBound>,
932        /// Used for Higher-Rank Trait Bounds (HRTBs)
933        /// ```rust
934        /// fn f<T>(x: T) where for<'a> &'a T: Iterator {}
935        /// //                  ^^^^^^^
936        /// ```
937        generic_params: Vec<GenericParamDef>,
938    },
939
940    /// A lifetime is expected to outlive other lifetimes.
941    LifetimePredicate {
942        /// The name of the lifetime.
943        lifetime: String,
944        /// The lifetimes that must be encompassed by the lifetime.
945        outlives: Vec<String>,
946    },
947
948    /// A type must exactly equal another type.
949    EqPredicate {
950        /// The left side of the equation.
951        lhs: Type,
952        /// The right side of the equation.
953        rhs: Term,
954    },
955}
956
957/// Either a trait bound or a lifetime bound.
958#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
959#[serde(rename_all = "snake_case")]
960pub enum GenericBound {
961    /// A trait bound.
962    TraitBound {
963        /// The full path to the trait.
964        #[serde(rename = "trait")]
965        trait_: Path,
966        /// Used for Higher-Rank Trait Bounds (HRTBs)
967        /// ```text
968        /// where F: for<'a, 'b> Fn(&'a u8, &'b u8)
969        ///          ^^^^^^^^^^^
970        ///          |
971        ///          this part
972        /// ```
973        generic_params: Vec<GenericParamDef>,
974        /// The context for which a trait is supposed to be used, e.g. `const
975        modifier: TraitBoundModifier,
976    },
977    /// A lifetime bound, e.g.
978    /// ```rust
979    /// fn f<'a, T>(x: &'a str, y: &T) where T: 'a {}
980    /// //                                     ^^^
981    /// ```
982    Outlives(String),
983    /// `use<'a, T>` precise-capturing bound syntax
984    Use(Vec<PreciseCapturingArg>),
985}
986
987/// A set of modifiers applied to a trait.
988#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
989#[serde(rename_all = "snake_case")]
990pub enum TraitBoundModifier {
991    /// Marks the absence of a modifier.
992    None,
993    /// Indicates that the trait bound relaxes a trait bound applied to a parameter by default,
994    /// e.g. `T: Sized?`, the `Sized` trait is required for all generic type parameters by default
995    /// unless specified otherwise with this modifier.
996    Maybe,
997    /// Indicates that the trait bound must be applicable in both a run-time and a compile-time
998    /// context.
999    MaybeConst,
1000}
1001
1002/// One precise capturing argument. See [the rust reference](https://doc.rust-lang.org/reference/types/impl-trait.html#precise-capturing).
1003#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1004#[serde(rename_all = "snake_case")]
1005pub enum PreciseCapturingArg {
1006    /// A lifetime.
1007    /// ```rust
1008    /// pub fn hello<'a, T, const N: usize>() -> impl Sized + use<'a, T, N> {}
1009    /// //                                                        ^^
1010    Lifetime(String),
1011    /// A type or constant parameter.
1012    /// ```rust
1013    /// pub fn hello<'a, T, const N: usize>() -> impl Sized + use<'a, T, N> {}
1014    /// //                                                            ^  ^
1015    Param(String),
1016}
1017
1018/// Either a type or a constant, usually stored as the right-hand side of an equation in places like
1019/// [`AssocItemConstraint`]
1020#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1021#[serde(rename_all = "snake_case")]
1022pub enum Term {
1023    /// A type.
1024    ///
1025    /// ```rust
1026    /// fn f(x: impl IntoIterator<Item = u32>) {}
1027    /// //                               ^^^
1028    /// ```
1029    Type(Type),
1030    /// A constant.
1031    ///
1032    /// ```ignore (incomplete feature in the snippet)
1033    /// trait Foo {
1034    ///     const BAR: usize;
1035    /// }
1036    ///
1037    /// fn f(x: impl Foo<BAR = 42>) {}
1038    /// //                     ^^
1039    /// ```
1040    Constant(Constant),
1041}
1042
1043/// A type.
1044#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1045#[serde(rename_all = "snake_case")]
1046pub enum Type {
1047    /// Structs, enums, unions and type aliases, e.g. `std::option::Option<u32>`
1048    ResolvedPath(Path),
1049    /// Dynamic trait object type (`dyn Trait`).
1050    DynTrait(DynTrait),
1051    /// Parameterized types. The contained string is the name of the parameter.
1052    Generic(String),
1053    /// Built-in numeric types (e.g. `u32`, `f32`), `bool`, `char`.
1054    Primitive(String),
1055    /// A function pointer type, e.g. `fn(u32) -> u32`, `extern "C" fn() -> *const u8`
1056    FunctionPointer(Box<FunctionPointer>),
1057    /// A tuple type, e.g. `(String, u32, Box<usize>)`
1058    Tuple(Vec<Type>),
1059    /// An unsized slice type, e.g. `[u32]`.
1060    Slice(Box<Type>),
1061    /// An array type, e.g. `[u32; 15]`
1062    Array {
1063        /// The type of the contained element.
1064        #[serde(rename = "type")]
1065        type_: Box<Type>,
1066        /// The stringified expression that is the length of the array.
1067        ///
1068        /// Keep in mind that it's not guaranteed to match the actual source code of the expression.
1069        len: String,
1070    },
1071    /// A pattern type, e.g. `u32 is 1..`
1072    ///
1073    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/123646)
1074    Pat {
1075        /// The base type, e.g. the `u32` in `u32 is 1..`
1076        #[serde(rename = "type")]
1077        type_: Box<Type>,
1078        #[doc(hidden)]
1079        __pat_unstable_do_not_use: String,
1080    },
1081    /// An opaque type that satisfies a set of bounds, `impl TraitA + TraitB + ...`
1082    ImplTrait(Vec<GenericBound>),
1083    /// A type that's left to be inferred, `_`
1084    Infer,
1085    /// A raw pointer type, e.g. `*mut u32`, `*const u8`, etc.
1086    RawPointer {
1087        /// This is `true` for `*mut _` and `false` for `*const _`.
1088        is_mutable: bool,
1089        /// The type of the pointee.
1090        #[serde(rename = "type")]
1091        type_: Box<Type>,
1092    },
1093    /// `&'a mut String`, `&str`, etc.
1094    BorrowedRef {
1095        /// The name of the lifetime of the reference, if provided.
1096        lifetime: Option<String>,
1097        /// This is `true` for `&mut i32` and `false` for `&i32`
1098        is_mutable: bool,
1099        /// The type of the pointee, e.g. the `i32` in `&'a mut i32`
1100        #[serde(rename = "type")]
1101        type_: Box<Type>,
1102    },
1103    /// Associated types like `<Type as Trait>::Name` and `T::Item` where
1104    /// `T: Iterator` or inherent associated types like `Struct::Name`.
1105    QualifiedPath {
1106        /// The name of the associated type in the parent type.
1107        ///
1108        /// ```ignore (incomplete expression)
1109        /// <core::array::IntoIter<u32, 42> as Iterator>::Item
1110        /// //                                            ^^^^
1111        /// ```
1112        name: String,
1113        /// The generic arguments provided to the associated type.
1114        ///
1115        /// ```ignore (incomplete expression)
1116        /// <core::slice::IterMut<'static, u32> as BetterIterator>::Item<'static>
1117        /// //                                                          ^^^^^^^^^
1118        /// ```
1119        args: Box<GenericArgs>,
1120        /// The type with which this type is associated.
1121        ///
1122        /// ```ignore (incomplete expression)
1123        /// <core::array::IntoIter<u32, 42> as Iterator>::Item
1124        /// // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1125        /// ```
1126        self_type: Box<Type>,
1127        /// `None` iff this is an *inherent* associated type.
1128        #[serde(rename = "trait")]
1129        trait_: Option<Path>,
1130    },
1131}
1132
1133/// A type that has a simple path to it. This is the kind of type of structs, unions, enums, etc.
1134#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1135pub struct Path {
1136    /// The path of the type.
1137    ///
1138    /// This will be the path that is *used* (not where it is defined), so
1139    /// multiple `Path`s may have different values for this field even if
1140    /// they all refer to the same item. e.g.
1141    ///
1142    /// ```rust
1143    /// pub type Vec1 = std::vec::Vec<i32>; // path: "std::vec::Vec"
1144    /// pub type Vec2 = Vec<i32>; // path: "Vec"
1145    /// pub type Vec3 = std::prelude::v1::Vec<i32>; // path: "std::prelude::v1::Vec"
1146    /// ```
1147    //
1148    // Example tested in ./tests/rustdoc-json/path_name.rs
1149    pub path: String,
1150    /// The ID of the type.
1151    pub id: Id,
1152    /// Generic arguments to the type.
1153    ///
1154    /// ```ignore (incomplete expression)
1155    /// std::borrow::Cow<'static, str>
1156    /// //              ^^^^^^^^^^^^^^
1157    /// ```
1158    pub args: Option<Box<GenericArgs>>,
1159}
1160
1161/// A type that is a function pointer.
1162#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1163pub struct FunctionPointer {
1164    /// The signature of the function.
1165    pub sig: FunctionSignature,
1166    /// Used for Higher-Rank Trait Bounds (HRTBs)
1167    ///
1168    /// ```ignore (incomplete expression)
1169    ///    for<'c> fn(val: &'c i32) -> i32
1170    /// // ^^^^^^^
1171    /// ```
1172    pub generic_params: Vec<GenericParamDef>,
1173    /// The core properties of the function, such as the ABI it conforms to, whether it's unsafe, etc.
1174    pub header: FunctionHeader,
1175}
1176
1177/// The signature of a function.
1178#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1179pub struct FunctionSignature {
1180    /// List of argument names and their type.
1181    ///
1182    /// Note that not all names will be valid identifiers, as some of
1183    /// them may be patterns.
1184    pub inputs: Vec<(String, Type)>,
1185    /// The output type, if specified.
1186    pub output: Option<Type>,
1187    /// Whether the function accepts an arbitrary amount of trailing arguments the C way.
1188    ///
1189    /// ```ignore (incomplete code)
1190    /// fn printf(fmt: &str, ...);
1191    /// ```
1192    pub is_c_variadic: bool,
1193}
1194
1195/// A `trait` declaration.
1196#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1197pub struct Trait {
1198    /// Whether the trait is marked `auto` and is thus implemented automatically
1199    /// for all applicable types.
1200    pub is_auto: bool,
1201    /// Whether the trait is marked as `unsafe`.
1202    pub is_unsafe: bool,
1203    /// Whether the trait is [dyn compatible](https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility)[^1].
1204    ///
1205    /// [^1]: Formerly known as "object safe".
1206    pub is_dyn_compatible: bool,
1207    /// Associated [`Item`]s that can/must be implemented by the `impl` blocks.
1208    pub items: Vec<Id>,
1209    /// Information about the type parameters and `where` clauses of the trait.
1210    pub generics: Generics,
1211    /// Constraints that must be met by the implementor of the trait.
1212    pub bounds: Vec<GenericBound>,
1213    /// The implementations of the trait.
1214    pub implementations: Vec<Id>,
1215}
1216
1217/// A trait alias declaration, e.g. `trait Int = Add + Sub + Mul + Div;`
1218///
1219/// See [the tracking issue](https://github.com/rust-lang/rust/issues/41517)
1220#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1221pub struct TraitAlias {
1222    /// Information about the type parameters and `where` clauses of the alias.
1223    pub generics: Generics,
1224    /// The bounds that are associated with the alias.
1225    pub params: Vec<GenericBound>,
1226}
1227
1228/// An `impl` block.
1229#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1230pub struct Impl {
1231    /// Whether this impl is for an unsafe trait.
1232    pub is_unsafe: bool,
1233    /// Information about the impl’s type parameters and `where` clauses.
1234    pub generics: Generics,
1235    /// The list of the names of all the trait methods that weren't mentioned in this impl but
1236    /// were provided by the trait itself.
1237    ///
1238    /// For example, for this impl of the [`PartialEq`] trait:
1239    /// ```rust
1240    /// struct Foo;
1241    ///
1242    /// impl PartialEq for Foo {
1243    ///     fn eq(&self, other: &Self) -> bool { todo!() }
1244    /// }
1245    /// ```
1246    /// This field will be `["ne"]`, as it has a default implementation defined for it.
1247    pub provided_trait_methods: Vec<String>,
1248    /// The trait being implemented or `None` if the impl is inherent, which means
1249    /// `impl Struct {}` as opposed to `impl Trait for Struct {}`.
1250    #[serde(rename = "trait")]
1251    pub trait_: Option<Path>,
1252    /// The type that the impl block is for.
1253    #[serde(rename = "for")]
1254    pub for_: Type,
1255    /// The list of associated items contained in this impl block.
1256    pub items: Vec<Id>,
1257    /// Whether this is a negative impl (e.g. `!Sized` or `!Send`).
1258    pub is_negative: bool,
1259    /// Whether this is an impl that’s implied by the compiler
1260    /// (for autotraits, e.g. `Send` or `Sync`).
1261    pub is_synthetic: bool,
1262    // FIXME: document this
1263    pub blanket_impl: Option<Type>,
1264}
1265
1266/// A `use` statement.
1267#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1268#[serde(rename_all = "snake_case")]
1269pub struct Use {
1270    /// The full path being imported.
1271    pub source: String,
1272    /// May be different from the last segment of `source` when renaming imports:
1273    /// `use source as name;`
1274    pub name: String,
1275    /// The ID of the item being imported. Will be `None` in case of re-exports of primitives:
1276    /// ```rust
1277    /// pub use i32 as my_i32;
1278    /// ```
1279    pub id: Option<Id>,
1280    /// Whether this statement is a wildcard `use`, e.g. `use source::*;`
1281    pub is_glob: bool,
1282}
1283
1284/// A procedural macro.
1285#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1286pub struct ProcMacro {
1287    /// How this macro is supposed to be called: `foo!()`, `#[foo]` or `#[derive(foo)]`
1288    pub kind: MacroKind,
1289    /// Helper attributes defined by a macro to be used inside it.
1290    ///
1291    /// Defined only for derive macros.
1292    ///
1293    /// E.g. the [`Default`] derive macro defines a `#[default]` helper attribute so that one can
1294    /// do:
1295    ///
1296    /// ```rust
1297    /// #[derive(Default)]
1298    /// enum Option<T> {
1299    ///     #[default]
1300    ///     None,
1301    ///     Some(T),
1302    /// }
1303    /// ```
1304    pub helpers: Vec<String>,
1305}
1306
1307/// The way a [`ProcMacro`] is declared to be used.
1308#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1309#[serde(rename_all = "snake_case")]
1310pub enum MacroKind {
1311    /// A bang macro `foo!()`.
1312    Bang,
1313    /// An attribute macro `#[foo]`.
1314    Attr,
1315    /// A derive macro `#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]`
1316    Derive,
1317}
1318
1319/// A type alias declaration, e.g. `type Pig = std::borrow::Cow<'static, str>;`
1320#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1321pub struct TypeAlias {
1322    /// The type referred to by this alias.
1323    #[serde(rename = "type")]
1324    pub type_: Type,
1325    /// Information about the type parameters and `where` clauses of the alias.
1326    pub generics: Generics,
1327}
1328
1329/// A `static` declaration.
1330#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1331pub struct Static {
1332    /// The type of the static.
1333    #[serde(rename = "type")]
1334    pub type_: Type,
1335    /// This is `true` for mutable statics, declared as `static mut X: T = f();`
1336    pub is_mutable: bool,
1337    /// The stringified expression for the initial value.
1338    ///
1339    /// It's not guaranteed that it'll match the actual source code for the initial value.
1340    pub expr: String,
1341
1342    /// Is the static `unsafe`?
1343    ///
1344    /// This is only true if it's in an `extern` block, and not explicity marked
1345    /// as `safe`.
1346    ///
1347    /// ```rust
1348    /// unsafe extern {
1349    ///     static A: i32;      // unsafe
1350    ///     safe static B: i32; // safe
1351    /// }
1352    ///
1353    /// static C: i32 = 0;     // safe
1354    /// static mut D: i32 = 0; // safe
1355    /// ```
1356    pub is_unsafe: bool,
1357}
1358
1359/// A primitive type declaration. Declarations of this kind can only come from the core library.
1360#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1361pub struct Primitive {
1362    /// The name of the type.
1363    pub name: String,
1364    /// The implementations, inherent and of traits, on the primitive type.
1365    pub impls: Vec<Id>,
1366}
1367
1368#[cfg(test)]
1369mod tests;