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_derive::{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.
33//
34// WARNING: When you update `FORMAT_VERSION`, please also update the "Latest feature" line with a
35// description of the change. This minimizes the risk of two concurrent PRs changing
36// `FORMAT_VERSION` from N to N+1 and git merging them without conflicts; the "Latest feature" line
37// will instead cause conflicts. See #94591 for more. (This paragraph and the "Latest feature" line
38// are deliberately not in a doc comment, because they need not be in public docs.)
39//
40// Latest feature: Add `ExternCrate::path`.
41pub const FORMAT_VERSION: u32 = 57;
42
43/// The root of the emitted JSON blob.
44///
45/// It contains all type/documentation information
46/// about the language items in the local crate, as well as info about external items to allow
47/// tools to find or link to them.
48#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
49pub struct Crate {
50    /// The id of the root [`Module`] item of the local crate.
51    pub root: Id,
52    /// The version string given to `--crate-version`, if any.
53    pub crate_version: Option<String>,
54    /// Whether or not the output includes private items.
55    pub includes_private: bool,
56    /// A collection of all items in the local crate as well as some external traits and their
57    /// items that are referenced locally.
58    pub index: HashMap<Id, Item>,
59    /// Maps IDs to fully qualified paths and other info helpful for generating links.
60    pub paths: HashMap<Id, ItemSummary>,
61    /// Maps `crate_id` of items to a crate name and html_root_url if it exists.
62    pub external_crates: HashMap<u32, ExternalCrate>,
63    /// Information about the target for which this documentation was generated
64    pub target: Target,
65    /// A single version number to be used in the future when making backwards incompatible changes
66    /// to the JSON output.
67    pub format_version: u32,
68}
69
70/// Information about a target
71#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
72pub struct Target {
73    /// The target triple for which this documentation was generated
74    pub triple: String,
75    /// A list of features valid for use in `#[target_feature]` attributes
76    /// for the target where this rustdoc JSON was generated.
77    pub target_features: Vec<TargetFeature>,
78}
79
80/// Information about a target feature.
81///
82/// Rust target features are used to influence code generation, especially around selecting
83/// instructions which are not universally supported by the target architecture.
84///
85/// Target features are commonly enabled by the [`#[target_feature]` attribute][1] to influence code
86/// generation for a particular function, and less commonly enabled by compiler options like
87/// `-Ctarget-feature` or `-Ctarget-cpu`. Targets themselves automatically enable certain target
88/// features by default, for example because the target's ABI specification requires saving specific
89/// registers which only exist in an architectural extension.
90///
91/// Target features can imply other target features: for example, x86-64 `avx2` implies `avx`, and
92/// aarch64 `sve2` implies `sve`, since both of these architectural extensions depend on their
93/// predecessors.
94///
95/// Target features can be probed at compile time by [`#[cfg(target_feature)]`][2] or `cfg!(…)`
96/// conditional compilation to determine whether a target feature is enabled in a particular
97/// context.
98///
99/// [1]: https://doc.rust-lang.org/stable/reference/attributes/codegen.html#the-target_feature-attribute
100/// [2]: https://doc.rust-lang.org/reference/conditional-compilation.html#target_feature
101#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
102pub struct TargetFeature {
103    /// The name of this target feature.
104    pub name: String,
105    /// Other target features which are implied by this target feature, if any.
106    pub implies_features: Vec<String>,
107    /// If this target feature is unstable, the name of the associated language feature gate.
108    pub unstable_feature_gate: Option<String>,
109    /// Whether this feature is globally enabled for this compilation session.
110    ///
111    /// Target features can be globally enabled implicitly as a result of the target's definition.
112    /// For example, x86-64 hardware floating point ABIs require saving x87 and SSE2 registers,
113    /// which in turn requires globally enabling the `x87` and `sse2` target features so that the
114    /// generated machine code conforms to the target's ABI.
115    ///
116    /// Target features can also be globally enabled explicitly as a result of compiler flags like
117    /// [`-Ctarget-feature`][1] or [`-Ctarget-cpu`][2].
118    ///
119    /// [1]: https://doc.rust-lang.org/beta/rustc/codegen-options/index.html#target-feature
120    /// [2]: https://doc.rust-lang.org/beta/rustc/codegen-options/index.html#target-cpu
121    pub globally_enabled: bool,
122}
123
124/// Metadata of a crate, either the same crate on which `rustdoc` was invoked, or its dependency.
125#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
126pub struct ExternalCrate {
127    /// The name of the crate.
128    ///
129    /// Note: This is the [*crate* name][crate-name], which may not be the same as the
130    /// [*package* name][package-name]. For example, for <https://crates.io/crates/regex-syntax>,
131    /// this field will be `regex_syntax` (which uses an `_`, not a `-`).
132    ///
133    /// [crate-name]: https://doc.rust-lang.org/stable/cargo/reference/cargo-targets.html#the-name-field
134    /// [package-name]: https://doc.rust-lang.org/stable/cargo/reference/manifest.html#the-name-field
135    pub name: String,
136    /// The root URL at which the crate's documentation lives.
137    pub html_root_url: Option<String>,
138
139    /// A path from where this crate was loaded.
140    ///
141    /// This will typically be a `.rlib` or `.rmeta`. It can be used to determine which crate
142    /// this was in terms of whatever build-system invoked rustc.
143    pub path: PathBuf,
144}
145
146/// Information about an external (not defined in the local crate) [`Item`].
147///
148/// For external items, you don't get the same level of
149/// information. This struct should contain enough to generate a link/reference to the item in
150/// question, or can be used by a tool that takes the json output of multiple crates to find
151/// the actual item definition with all the relevant info.
152#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
153pub struct ItemSummary {
154    /// Can be used to look up the name and html_root_url of the crate this item came from in the
155    /// `external_crates` map.
156    pub crate_id: u32,
157    /// The list of path components for the fully qualified path of this item (e.g.
158    /// `["std", "io", "lazy", "Lazy"]` for `std::io::lazy::Lazy`).
159    ///
160    /// Note that items can appear in multiple paths, and the one chosen is implementation
161    /// defined. Currently, this is the full path to where the item was defined. Eg
162    /// [`String`] is currently `["alloc", "string", "String"]` and [`HashMap`][`std::collections::HashMap`]
163    /// is `["std", "collections", "hash", "map", "HashMap"]`, but this is subject to change.
164    pub path: Vec<String>,
165    /// Whether this item is a struct, trait, macro, etc.
166    pub kind: ItemKind,
167}
168
169/// Anything that can hold documentation - modules, structs, enums, functions, traits, etc.
170///
171/// The `Item` data type holds fields that can apply to any of these,
172/// and leaves kind-specific details (like function args or enum variants) to the `inner` field.
173#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
174pub struct Item {
175    /// The unique identifier of this item. Can be used to find this item in various mappings.
176    pub id: Id,
177    /// This can be used as a key to the `external_crates` map of [`Crate`] to see which crate
178    /// this item came from.
179    pub crate_id: u32,
180    /// Some items such as impls don't have names.
181    pub name: Option<String>,
182    /// The source location of this item (absent if it came from a macro expansion or inline
183    /// assembly).
184    pub span: Option<Span>,
185    /// By default all documented items are public, but you can tell rustdoc to output private items
186    /// so this field is needed to differentiate.
187    pub visibility: Visibility,
188    /// The full markdown docstring of this item. Absent if there is no documentation at all,
189    /// Some("") if there is some documentation but it is empty (EG `#[doc = ""]`).
190    pub docs: Option<String>,
191    /// 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
192    pub links: HashMap<String, Id>,
193    /// Attributes on this item.
194    ///
195    /// Does not include `#[deprecated]` attributes: see the [`Self::deprecation`] field instead.
196    ///
197    /// Attributes appear in pretty-printed Rust form, regardless of their formatting
198    /// in the original source code. For example:
199    /// - `#[non_exhaustive]` and `#[must_use]` are represented as themselves.
200    /// - `#[no_mangle]` and `#[export_name]` are also represented as themselves.
201    /// - `#[repr(C)]` and other reprs also appear as themselves,
202    ///   though potentially with a different order: e.g. `repr(i8, C)` may become `repr(C, i8)`.
203    ///   Multiple repr attributes on the same item may be combined into an equivalent single attr.
204    pub attrs: Vec<Attribute>,
205    /// Information about the item’s deprecation, if present.
206    pub deprecation: Option<Deprecation>,
207    /// The type-specific fields describing this item.
208    pub inner: ItemEnum,
209}
210
211#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
212#[serde(rename_all = "snake_case")]
213/// An attribute, e.g. `#[repr(C)]`
214///
215/// This doesn't include:
216/// - `#[doc = "Doc Comment"]` or `/// Doc comment`. These are in [`Item::docs`] instead.
217/// - `#[deprecated]`. These are in [`Item::deprecation`] instead.
218pub enum Attribute {
219    /// `#[non_exhaustive]`
220    NonExhaustive,
221
222    /// `#[must_use]`
223    MustUse { reason: Option<String> },
224
225    /// `#[macro_export]`
226    MacroExport,
227
228    /// `#[export_name = "name"]`
229    ExportName(String),
230
231    /// `#[link_section = "name"]`
232    LinkSection(String),
233
234    /// `#[automatically_derived]`
235    AutomaticallyDerived,
236
237    /// `#[repr]`
238    Repr(AttributeRepr),
239
240    /// `#[no_mangle]`
241    NoMangle,
242
243    /// #[target_feature(enable = "feature1", enable = "feature2")]
244    TargetFeature { enable: Vec<String> },
245
246    /// Something else.
247    ///
248    /// Things here are explicitly *not* covered by the [`FORMAT_VERSION`]
249    /// constant, and may change without bumping the format version.
250    ///
251    /// As an implementation detail, this is currently either:
252    /// 1. A HIR debug printing, like `"#[attr = Optimize(Speed)]"`
253    /// 2. The attribute as it appears in source form, like
254    ///    `"#[optimize(speed)]"`.
255    Other(String),
256}
257
258#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
259/// The contents of a `#[repr(...)]` attribute.
260///
261/// Used in [`Attribute::Repr`].
262pub struct AttributeRepr {
263    /// The representation, e.g. `#[repr(C)]`, `#[repr(transparent)]`
264    pub kind: ReprKind,
265
266    /// Alignment in bytes, if explicitly specified by `#[repr(align(...)]`.
267    pub align: Option<u64>,
268    /// Alignment in bytes, if explicitly specified by `#[repr(packed(...)]]`.
269    pub packed: Option<u64>,
270
271    /// The integer type for an enum descriminant, if explicitly specified.
272    ///
273    /// e.g. `"i32"`, for `#[repr(C, i32)]`
274    pub int: Option<String>,
275}
276
277#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
278#[serde(rename_all = "snake_case")]
279/// The kind of `#[repr]`.
280///
281/// See [AttributeRepr::kind]`.
282pub enum ReprKind {
283    /// `#[repr(Rust)]`
284    ///
285    /// Also the default.
286    Rust,
287    /// `#[repr(C)]`
288    C,
289    /// `#[repr(transparent)]
290    Transparent,
291    /// `#[repr(simd)]`
292    Simd,
293}
294
295/// A range of source code.
296#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
297pub struct Span {
298    /// The path to the source file for this span relative to the path `rustdoc` was invoked with.
299    pub filename: PathBuf,
300    /// One indexed Line and Column of the first character of the `Span`.
301    pub begin: (usize, usize),
302    /// One indexed Line and Column of the last character of the `Span`.
303    pub end: (usize, usize),
304}
305
306/// Information about the deprecation of an [`Item`].
307#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
308pub struct Deprecation {
309    /// Usually a version number when this [`Item`] first became deprecated.
310    pub since: Option<String>,
311    /// The reason for deprecation and/or what alternatives to use.
312    pub note: Option<String>,
313}
314
315/// Visibility of an [`Item`].
316#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
317#[serde(rename_all = "snake_case")]
318pub enum Visibility {
319    /// Explicitly public visibility set with `pub`.
320    Public,
321    /// For the most part items are private by default. The exceptions are associated items of
322    /// public traits and variants of public enums.
323    Default,
324    /// Explicitly crate-wide visibility set with `pub(crate)`
325    Crate,
326    /// For `pub(in path)` visibility.
327    Restricted {
328        /// ID of the module to which this visibility restricts items.
329        parent: Id,
330        /// The path with which [`parent`] was referenced
331        /// (like `super::super` or `crate::foo::bar`).
332        ///
333        /// [`parent`]: Visibility::Restricted::parent
334        path: String,
335    },
336}
337
338/// Dynamic trait object type (`dyn Trait`).
339#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
340pub struct DynTrait {
341    /// All the traits implemented. One of them is the vtable, and the rest must be auto traits.
342    pub traits: Vec<PolyTrait>,
343    /// The lifetime of the whole dyn object
344    /// ```text
345    /// dyn Debug + 'static
346    ///             ^^^^^^^
347    ///             |
348    ///             this part
349    /// ```
350    pub lifetime: Option<String>,
351}
352
353/// A trait and potential HRTBs
354#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
355pub struct PolyTrait {
356    /// The path to the trait.
357    #[serde(rename = "trait")]
358    pub trait_: Path,
359    /// Used for Higher-Rank Trait Bounds (HRTBs)
360    /// ```text
361    /// dyn for<'a> Fn() -> &'a i32"
362    ///     ^^^^^^^
363    /// ```
364    pub generic_params: Vec<GenericParamDef>,
365}
366
367/// A set of generic arguments provided to a path segment, e.g.
368///
369/// ```text
370/// std::option::Option<u32>
371///                    ^^^^^
372/// ```
373#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
374#[serde(rename_all = "snake_case")]
375pub enum GenericArgs {
376    /// `<'a, 32, B: Copy, C = u32>`
377    AngleBracketed {
378        /// The list of each argument on this type.
379        /// ```text
380        /// <'a, 32, B: Copy, C = u32>
381        ///  ^^^^^^
382        /// ```
383        args: Vec<GenericArg>,
384        /// Associated type or constant bindings (e.g. `Item=i32` or `Item: Clone`) for this type.
385        constraints: Vec<AssocItemConstraint>,
386    },
387    /// `Fn(A, B) -> C`
388    Parenthesized {
389        /// The input types, enclosed in parentheses.
390        inputs: Vec<Type>,
391        /// The output type provided after the `->`, if present.
392        output: Option<Type>,
393    },
394    /// `T::method(..)`
395    ReturnTypeNotation,
396}
397
398/// One argument in a list of generic arguments to a path segment.
399///
400/// Part of [`GenericArgs`].
401#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
402#[serde(rename_all = "snake_case")]
403pub enum GenericArg {
404    /// A lifetime argument.
405    /// ```text
406    /// std::borrow::Cow<'static, str>
407    ///                  ^^^^^^^
408    /// ```
409    Lifetime(String),
410    /// A type argument.
411    /// ```text
412    /// std::borrow::Cow<'static, str>
413    ///                           ^^^
414    /// ```
415    Type(Type),
416    /// A constant as a generic argument.
417    /// ```text
418    /// core::array::IntoIter<u32, { 640 * 1024 }>
419    ///                            ^^^^^^^^^^^^^^
420    /// ```
421    Const(Constant),
422    /// A generic argument that's explicitly set to be inferred.
423    /// ```text
424    /// std::vec::Vec::<_>
425    ///                 ^
426    /// ```
427    Infer,
428}
429
430/// A constant.
431#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
432pub struct Constant {
433    /// The stringified expression of this constant. Note that its mapping to the original
434    /// source code is unstable and it's not guaranteed that it'll match the source code.
435    pub expr: String,
436    /// The value of the evaluated expression for this constant, which is only computed for numeric
437    /// types.
438    pub value: Option<String>,
439    /// Whether this constant is a bool, numeric, string, or char literal.
440    pub is_literal: bool,
441}
442
443/// Describes a bound applied to an associated type/constant.
444///
445/// Example:
446/// ```text
447/// IntoIterator<Item = u32, IntoIter: Clone>
448///              ^^^^^^^^^^  ^^^^^^^^^^^^^^^
449/// ```
450#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
451pub struct AssocItemConstraint {
452    /// The name of the associated type/constant.
453    pub name: String,
454    /// Arguments provided to the associated type/constant.
455    pub args: Option<Box<GenericArgs>>,
456    /// The kind of bound applied to the associated type/constant.
457    pub binding: AssocItemConstraintKind,
458}
459
460/// The way in which an associate type/constant is bound.
461#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
462#[serde(rename_all = "snake_case")]
463pub enum AssocItemConstraintKind {
464    /// The required value/type is specified exactly. e.g.
465    /// ```text
466    /// Iterator<Item = u32, IntoIter: DoubleEndedIterator>
467    ///          ^^^^^^^^^^
468    /// ```
469    Equality(Term),
470    /// The type is required to satisfy a set of bounds.
471    /// ```text
472    /// Iterator<Item = u32, IntoIter: DoubleEndedIterator>
473    ///                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
474    /// ```
475    Constraint(Vec<GenericBound>),
476}
477
478/// An opaque identifier for an item.
479///
480/// It can be used to lookup in [`Crate::index`] or [`Crate::paths`] to resolve it
481/// to an [`Item`].
482///
483/// Id's are only valid within a single JSON blob. They cannot be used to
484/// resolve references between the JSON output's for different crates.
485///
486/// Rustdoc makes no guarantees about the inner value of Id's. Applications
487/// should treat them as opaque keys to lookup items, and avoid attempting
488/// to parse them, or otherwise depend on any implementation details.
489#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
490// FIXME(aDotInTheVoid): Consider making this non-public in rustdoc-types.
491pub struct Id(pub u32);
492
493/// The fundamental kind of an item. Unlike [`ItemEnum`], this does not carry any additional info.
494///
495/// Part of [`ItemSummary`].
496#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
497#[serde(rename_all = "snake_case")]
498pub enum ItemKind {
499    /// A module declaration, e.g. `mod foo;` or `mod foo {}`
500    Module,
501    /// A crate imported via the `extern crate` syntax.
502    ExternCrate,
503    /// An import of 1 or more items into scope, using the `use` keyword.
504    Use,
505    /// A `struct` declaration.
506    Struct,
507    /// A field of a struct.
508    StructField,
509    /// A `union` declaration.
510    Union,
511    /// An `enum` declaration.
512    Enum,
513    /// A variant of a enum.
514    Variant,
515    /// A function declaration, e.g. `fn f() {}`
516    Function,
517    /// A type alias declaration, e.g. `type Pig = std::borrow::Cow<'static, str>;`
518    TypeAlias,
519    /// The declaration of a constant, e.g. `const GREETING: &str = "Hi :3";`
520    Constant,
521    /// A `trait` declaration.
522    Trait,
523    /// A trait alias declaration, e.g. `trait Int = Add + Sub + Mul + Div;`
524    ///
525    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/41517)
526    TraitAlias,
527    /// An `impl` block.
528    Impl,
529    /// A `static` declaration.
530    Static,
531    /// `type`s from an `extern` block.
532    ///
533    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/43467)
534    ExternType,
535    /// A macro declaration.
536    ///
537    /// Corresponds to either `ItemEnum::Macro(_)`
538    /// or `ItemEnum::ProcMacro(ProcMacro { kind: MacroKind::Bang })`
539    Macro,
540    /// A procedural macro attribute.
541    ///
542    /// Corresponds to `ItemEnum::ProcMacro(ProcMacro { kind: MacroKind::Attr })`
543    ProcAttribute,
544    /// A procedural macro usable in the `#[derive()]` attribute.
545    ///
546    /// Corresponds to `ItemEnum::ProcMacro(ProcMacro { kind: MacroKind::Derive })`
547    ProcDerive,
548    /// An associated constant of a trait or a type.
549    AssocConst,
550    /// An associated type of a trait or a type.
551    AssocType,
552    /// A primitive type, e.g. `u32`.
553    ///
554    /// [`Item`]s of this kind only come from the core library.
555    Primitive,
556    /// A keyword declaration.
557    ///
558    /// [`Item`]s of this kind only come from the come library and exist solely
559    /// to carry documentation for the respective keywords.
560    Keyword,
561    /// An attribute declaration.
562    ///
563    /// [`Item`]s of this kind only come from the core library and exist solely
564    /// to carry documentation for the respective builtin attributes.
565    Attribute,
566}
567
568/// Specific fields of an item.
569///
570/// Part of [`Item`].
571#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
572#[serde(rename_all = "snake_case")]
573pub enum ItemEnum {
574    /// A module declaration, e.g. `mod foo;` or `mod foo {}`
575    Module(Module),
576    /// A crate imported via the `extern crate` syntax.
577    ExternCrate {
578        /// The name of the imported crate.
579        name: String,
580        /// If the crate is renamed, this is its name in the crate.
581        rename: Option<String>,
582    },
583    /// An import of 1 or more items into scope, using the `use` keyword.
584    Use(Use),
585
586    /// A `union` declaration.
587    Union(Union),
588    /// A `struct` declaration.
589    Struct(Struct),
590    /// A field of a struct.
591    StructField(Type),
592    /// An `enum` declaration.
593    Enum(Enum),
594    /// A variant of a enum.
595    Variant(Variant),
596
597    /// A function declaration (including methods and other associated functions)
598    Function(Function),
599
600    /// A `trait` declaration.
601    Trait(Trait),
602    /// A trait alias declaration, e.g. `trait Int = Add + Sub + Mul + Div;`
603    ///
604    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/41517)
605    TraitAlias(TraitAlias),
606    /// An `impl` block.
607    Impl(Impl),
608
609    /// A type alias declaration, e.g. `type Pig = std::borrow::Cow<'static, str>;`
610    TypeAlias(TypeAlias),
611    /// The declaration of a constant, e.g. `const GREETING: &str = "Hi :3";`
612    Constant {
613        /// The type of the constant.
614        #[serde(rename = "type")]
615        type_: Type,
616        /// The declared constant itself.
617        #[serde(rename = "const")]
618        const_: Constant,
619    },
620
621    /// A declaration of a `static`.
622    Static(Static),
623
624    /// `type`s from an `extern` block.
625    ///
626    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/43467)
627    ExternType,
628
629    /// A macro_rules! declarative macro. Contains a single string with the source
630    /// representation of the macro with the patterns stripped.
631    Macro(String),
632    /// A procedural macro.
633    ProcMacro(ProcMacro),
634
635    /// A primitive type, e.g. `u32`.
636    ///
637    /// [`Item`]s of this kind only come from the core library.
638    Primitive(Primitive),
639
640    /// An associated constant of a trait or a type.
641    AssocConst {
642        /// The type of the constant.
643        #[serde(rename = "type")]
644        type_: Type,
645        /// Inside a trait declaration, this is the default value for the associated constant,
646        /// if provided.
647        /// Inside an `impl` block, this is the value assigned to the associated constant,
648        /// and will always be present.
649        ///
650        /// The representation is implementation-defined and not guaranteed to be representative of
651        /// either the resulting value or of the source code.
652        ///
653        /// ```rust
654        /// const X: usize = 640 * 1024;
655        /// //               ^^^^^^^^^^
656        /// ```
657        value: Option<String>,
658    },
659    /// An associated type of a trait or a type.
660    AssocType {
661        /// The generic parameters and where clauses on ahis associated type.
662        generics: Generics,
663        /// The bounds for this associated type. e.g.
664        /// ```rust
665        /// trait IntoIterator {
666        ///     type Item;
667        ///     type IntoIter: Iterator<Item = Self::Item>;
668        /// //                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
669        /// }
670        /// ```
671        bounds: Vec<GenericBound>,
672        /// Inside a trait declaration, this is the default for the associated type, if provided.
673        /// Inside an impl block, this is the type assigned to the associated type, and will always
674        /// be present.
675        ///
676        /// ```rust
677        /// type X = usize;
678        /// //       ^^^^^
679        /// ```
680        #[serde(rename = "type")]
681        type_: Option<Type>,
682    },
683}
684
685/// A module declaration, e.g. `mod foo;` or `mod foo {}`.
686#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
687pub struct Module {
688    /// Whether this is the root item of a crate.
689    ///
690    /// This item doesn't correspond to any construction in the source code and is generated by the
691    /// compiler.
692    pub is_crate: bool,
693    /// [`Item`]s declared inside this module.
694    pub items: Vec<Id>,
695    /// If `true`, this module is not part of the public API, but it contains
696    /// items that are re-exported as public API.
697    pub is_stripped: bool,
698}
699
700/// A `union`.
701#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
702pub struct Union {
703    /// The generic parameters and where clauses on this union.
704    pub generics: Generics,
705    /// Whether any fields have been removed from the result, due to being private or hidden.
706    pub has_stripped_fields: bool,
707    /// The list of fields in the union.
708    ///
709    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::StructField`].
710    pub fields: Vec<Id>,
711    /// All impls (both of traits and inherent) for this union.
712    ///
713    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Impl`].
714    pub impls: Vec<Id>,
715}
716
717/// A `struct`.
718#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
719pub struct Struct {
720    /// The kind of the struct (e.g. unit, tuple-like or struct-like) and the data specific to it,
721    /// i.e. fields.
722    pub kind: StructKind,
723    /// The generic parameters and where clauses on this struct.
724    pub generics: Generics,
725    /// All impls (both of traits and inherent) for this struct.
726    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Impl`].
727    pub impls: Vec<Id>,
728}
729
730/// The kind of a [`Struct`] and the data specific to it, i.e. fields.
731#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
732#[serde(rename_all = "snake_case")]
733pub enum StructKind {
734    /// A struct with no fields and no parentheses.
735    ///
736    /// ```rust
737    /// pub struct Unit;
738    /// ```
739    Unit,
740    /// A struct with unnamed fields.
741    ///
742    /// All [`Id`]'s will point to [`ItemEnum::StructField`].
743    /// Unlike most of JSON, private and `#[doc(hidden)]` fields will be given as `None`
744    /// instead of being omitted, because order matters.
745    ///
746    /// ```rust
747    /// pub struct TupleStruct(i32);
748    /// pub struct EmptyTupleStruct();
749    /// ```
750    Tuple(Vec<Option<Id>>),
751    /// A struct with named fields.
752    ///
753    /// ```rust
754    /// pub struct PlainStruct { x: i32 }
755    /// pub struct EmptyPlainStruct {}
756    /// ```
757    Plain {
758        /// The list of fields in the struct.
759        ///
760        /// All of the corresponding [`Item`]s are of kind [`ItemEnum::StructField`].
761        fields: Vec<Id>,
762        /// Whether any fields have been removed from the result, due to being private or hidden.
763        has_stripped_fields: bool,
764    },
765}
766
767/// An `enum`.
768#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
769pub struct Enum {
770    /// Information about the type parameters and `where` clauses of the enum.
771    pub generics: Generics,
772    /// Whether any variants have been removed from the result, due to being private or hidden.
773    pub has_stripped_variants: bool,
774    /// The list of variants in the enum.
775    ///
776    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Variant`]
777    pub variants: Vec<Id>,
778    /// `impl`s for the enum.
779    pub impls: Vec<Id>,
780}
781
782/// A variant of an enum.
783#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
784pub struct Variant {
785    /// Whether the variant is plain, a tuple-like, or struct-like. Contains the fields.
786    pub kind: VariantKind,
787    /// The discriminant, if explicitly specified.
788    pub discriminant: Option<Discriminant>,
789}
790
791/// The kind of an [`Enum`] [`Variant`] and the data specific to it, i.e. fields.
792#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
793#[serde(rename_all = "snake_case")]
794pub enum VariantKind {
795    /// A variant with no parentheses
796    ///
797    /// ```rust
798    /// enum Demo {
799    ///     PlainVariant,
800    ///     PlainWithDiscriminant = 1,
801    /// }
802    /// ```
803    Plain,
804    /// A variant with unnamed fields.
805    ///
806    /// All [`Id`]'s will point to [`ItemEnum::StructField`].
807    /// Unlike most of JSON, `#[doc(hidden)]` fields will be given as `None`
808    /// instead of being omitted, because order matters.
809    ///
810    /// ```rust
811    /// enum Demo {
812    ///     TupleVariant(i32),
813    ///     EmptyTupleVariant(),
814    /// }
815    /// ```
816    Tuple(Vec<Option<Id>>),
817    /// A variant with named fields.
818    ///
819    /// ```rust
820    /// enum Demo {
821    ///     StructVariant { x: i32 },
822    ///     EmptyStructVariant {},
823    /// }
824    /// ```
825    Struct {
826        /// The list of variants in the enum.
827        /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Variant`].
828        fields: Vec<Id>,
829        /// Whether any variants have been removed from the result, due to being private or hidden.
830        has_stripped_fields: bool,
831    },
832}
833
834/// The value that distinguishes a variant in an [`Enum`] from other variants.
835#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
836pub struct Discriminant {
837    /// The expression that produced the discriminant.
838    ///
839    /// Unlike `value`, this preserves the original formatting (eg suffixes,
840    /// hexadecimal, and underscores), making it unsuitable to be machine
841    /// interpreted.
842    ///
843    /// In some cases, when the value is too complex, this may be `"{ _ }"`.
844    /// When this occurs is unstable, and may change without notice.
845    pub expr: String,
846    /// The numerical value of the discriminant. Stored as a string due to
847    /// JSON's poor support for large integers, and the fact that it would need
848    /// to store from [`i128::MIN`] to [`u128::MAX`].
849    pub value: String,
850}
851
852/// A set of fundamental properties of a function.
853#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
854pub struct FunctionHeader {
855    /// Is this function marked as `const`?
856    pub is_const: bool,
857    /// Is this function unsafe?
858    pub is_unsafe: bool,
859    /// Is this function async?
860    pub is_async: bool,
861    /// The ABI used by the function.
862    pub abi: Abi,
863}
864
865/// The ABI (Application Binary Interface) used by a function.
866///
867/// If a variant has an `unwind` field, this means the ABI that it represents can be specified in 2
868/// ways: `extern "_"` and `extern "_-unwind"`, and a value of `true` for that field signifies the
869/// latter variant.
870///
871/// See the [Rustonomicon section](https://doc.rust-lang.org/nightly/nomicon/ffi.html#ffi-and-unwinding)
872/// on unwinding for more info.
873#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
874pub enum Abi {
875    // We only have a concrete listing here for stable ABI's because there are so many
876    // See rustc_ast_passes::feature_gate::PostExpansionVisitor::check_abi for the list
877    /// The default ABI, but that can also be written explicitly with `extern "Rust"`.
878    Rust,
879    /// Can be specified as `extern "C"` or, as a shorthand, just `extern`.
880    C { unwind: bool },
881    /// Can be specified as `extern "cdecl"`.
882    Cdecl { unwind: bool },
883    /// Can be specified as `extern "stdcall"`.
884    Stdcall { unwind: bool },
885    /// Can be specified as `extern "fastcall"`.
886    Fastcall { unwind: bool },
887    /// Can be specified as `extern "aapcs"`.
888    Aapcs { unwind: bool },
889    /// Can be specified as `extern "win64"`.
890    Win64 { unwind: bool },
891    /// Can be specified as `extern "sysv64"`.
892    SysV64 { unwind: bool },
893    /// Can be specified as `extern "system"`.
894    System { unwind: bool },
895    /// Any other ABI, including unstable ones.
896    Other(String),
897}
898
899/// A function declaration (including methods and other associated functions).
900#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
901pub struct Function {
902    /// Information about the function signature, or declaration.
903    pub sig: FunctionSignature,
904    /// Information about the function’s type parameters and `where` clauses.
905    pub generics: Generics,
906    /// Information about core properties of the function, e.g. whether it's `const`, its ABI, etc.
907    pub header: FunctionHeader,
908    /// Whether the function has a body, i.e. an implementation.
909    pub has_body: bool,
910}
911
912/// Generic parameters accepted by an item and `where` clauses imposed on it and the parameters.
913#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
914pub struct Generics {
915    /// A list of generic parameter definitions (e.g. `<T: Clone + Hash, U: Copy>`).
916    pub params: Vec<GenericParamDef>,
917    /// A list of where predicates (e.g. `where T: Iterator, T::Item: Copy`).
918    pub where_predicates: Vec<WherePredicate>,
919}
920
921/// One generic parameter accepted by an item.
922#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
923pub struct GenericParamDef {
924    /// Name of the parameter.
925    /// ```rust
926    /// fn f<'resource, Resource>(x: &'resource Resource) {}
927    /// //    ^^^^^^^^  ^^^^^^^^
928    /// ```
929    pub name: String,
930    /// The kind of the parameter and data specific to a particular parameter kind, e.g. type
931    /// bounds.
932    pub kind: GenericParamDefKind,
933}
934
935/// The kind of a [`GenericParamDef`].
936#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
937#[serde(rename_all = "snake_case")]
938pub enum GenericParamDefKind {
939    /// Denotes a lifetime parameter.
940    Lifetime {
941        /// Lifetimes that this lifetime parameter is required to outlive.
942        ///
943        /// ```rust
944        /// fn f<'a, 'b, 'resource: 'a + 'b>(a: &'a str, b: &'b str, res: &'resource str) {}
945        /// //                      ^^^^^^^
946        /// ```
947        outlives: Vec<String>,
948    },
949
950    /// Denotes a type parameter.
951    Type {
952        /// Bounds applied directly to the type. Note that the bounds from `where` clauses
953        /// that constrain this parameter won't appear here.
954        ///
955        /// ```rust
956        /// fn default2<T: Default>() -> [T; 2] where T: Clone { todo!() }
957        /// //             ^^^^^^^
958        /// ```
959        bounds: Vec<GenericBound>,
960        /// The default type for this parameter, if provided, e.g.
961        ///
962        /// ```rust
963        /// trait PartialEq<Rhs = Self> {}
964        /// //                    ^^^^
965        /// ```
966        default: Option<Type>,
967        /// This is normally `false`, which means that this generic parameter is
968        /// declared in the Rust source text.
969        ///
970        /// If it is `true`, this generic parameter has been introduced by the
971        /// compiler behind the scenes.
972        ///
973        /// # Example
974        ///
975        /// Consider
976        ///
977        /// ```ignore (pseudo-rust)
978        /// pub fn f(_: impl Trait) {}
979        /// ```
980        ///
981        /// The compiler will transform this behind the scenes to
982        ///
983        /// ```ignore (pseudo-rust)
984        /// pub fn f<impl Trait: Trait>(_: impl Trait) {}
985        /// ```
986        ///
987        /// In this example, the generic parameter named `impl Trait` (and which
988        /// is bound by `Trait`) is synthetic, because it was not originally in
989        /// the Rust source text.
990        is_synthetic: bool,
991    },
992
993    /// Denotes a constant parameter.
994    Const {
995        /// The type of the constant as declared.
996        #[serde(rename = "type")]
997        type_: Type,
998        /// The stringified expression for the default value, if provided. It's not guaranteed that
999        /// it'll match the actual source code for the default value.
1000        default: Option<String>,
1001    },
1002}
1003
1004/// One `where` clause.
1005/// ```rust
1006/// fn default<T>() -> T where T: Default { T::default() }
1007/// //                         ^^^^^^^^^^
1008/// ```
1009#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1010#[serde(rename_all = "snake_case")]
1011pub enum WherePredicate {
1012    /// A type is expected to comply with a set of bounds
1013    BoundPredicate {
1014        /// The type that's being constrained.
1015        ///
1016        /// ```rust
1017        /// fn f<T>(x: T) where for<'a> &'a T: Iterator {}
1018        /// //                              ^
1019        /// ```
1020        #[serde(rename = "type")]
1021        type_: Type,
1022        /// The set of bounds that constrain the type.
1023        ///
1024        /// ```rust
1025        /// fn f<T>(x: T) where for<'a> &'a T: Iterator {}
1026        /// //                                 ^^^^^^^^
1027        /// ```
1028        bounds: Vec<GenericBound>,
1029        /// Used for Higher-Rank Trait Bounds (HRTBs)
1030        /// ```rust
1031        /// fn f<T>(x: T) where for<'a> &'a T: Iterator {}
1032        /// //                  ^^^^^^^
1033        /// ```
1034        generic_params: Vec<GenericParamDef>,
1035    },
1036
1037    /// A lifetime is expected to outlive other lifetimes.
1038    LifetimePredicate {
1039        /// The name of the lifetime.
1040        lifetime: String,
1041        /// The lifetimes that must be encompassed by the lifetime.
1042        outlives: Vec<String>,
1043    },
1044
1045    /// A type must exactly equal another type.
1046    EqPredicate {
1047        /// The left side of the equation.
1048        lhs: Type,
1049        /// The right side of the equation.
1050        rhs: Term,
1051    },
1052}
1053
1054/// Either a trait bound or a lifetime bound.
1055#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1056#[serde(rename_all = "snake_case")]
1057pub enum GenericBound {
1058    /// A trait bound.
1059    TraitBound {
1060        /// The full path to the trait.
1061        #[serde(rename = "trait")]
1062        trait_: Path,
1063        /// Used for Higher-Rank Trait Bounds (HRTBs)
1064        /// ```text
1065        /// where F: for<'a, 'b> Fn(&'a u8, &'b u8)
1066        ///          ^^^^^^^^^^^
1067        ///          |
1068        ///          this part
1069        /// ```
1070        generic_params: Vec<GenericParamDef>,
1071        /// The context for which a trait is supposed to be used, e.g. `const
1072        modifier: TraitBoundModifier,
1073    },
1074    /// A lifetime bound, e.g.
1075    /// ```rust
1076    /// fn f<'a, T>(x: &'a str, y: &T) where T: 'a {}
1077    /// //                                     ^^^
1078    /// ```
1079    Outlives(String),
1080    /// `use<'a, T>` precise-capturing bound syntax
1081    Use(Vec<PreciseCapturingArg>),
1082}
1083
1084/// A set of modifiers applied to a trait.
1085#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1086#[serde(rename_all = "snake_case")]
1087pub enum TraitBoundModifier {
1088    /// Marks the absence of a modifier.
1089    None,
1090    /// Indicates that the trait bound relaxes a trait bound applied to a parameter by default,
1091    /// e.g. `T: Sized?`, the `Sized` trait is required for all generic type parameters by default
1092    /// unless specified otherwise with this modifier.
1093    Maybe,
1094    /// Indicates that the trait bound must be applicable in both a run-time and a compile-time
1095    /// context.
1096    MaybeConst,
1097}
1098
1099/// One precise capturing argument. See [the rust reference](https://doc.rust-lang.org/reference/types/impl-trait.html#precise-capturing).
1100#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1101#[serde(rename_all = "snake_case")]
1102pub enum PreciseCapturingArg {
1103    /// A lifetime.
1104    /// ```rust
1105    /// pub fn hello<'a, T, const N: usize>() -> impl Sized + use<'a, T, N> {}
1106    /// //                                                        ^^
1107    Lifetime(String),
1108    /// A type or constant parameter.
1109    /// ```rust
1110    /// pub fn hello<'a, T, const N: usize>() -> impl Sized + use<'a, T, N> {}
1111    /// //                                                            ^  ^
1112    Param(String),
1113}
1114
1115/// Either a type or a constant, usually stored as the right-hand side of an equation in places like
1116/// [`AssocItemConstraint`]
1117#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1118#[serde(rename_all = "snake_case")]
1119pub enum Term {
1120    /// A type.
1121    ///
1122    /// ```rust
1123    /// fn f(x: impl IntoIterator<Item = u32>) {}
1124    /// //                               ^^^
1125    /// ```
1126    Type(Type),
1127    /// A constant.
1128    ///
1129    /// ```ignore (incomplete feature in the snippet)
1130    /// trait Foo {
1131    ///     const BAR: usize;
1132    /// }
1133    ///
1134    /// fn f(x: impl Foo<BAR = 42>) {}
1135    /// //                     ^^
1136    /// ```
1137    Constant(Constant),
1138}
1139
1140/// A type.
1141#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1142#[serde(rename_all = "snake_case")]
1143pub enum Type {
1144    /// Structs, enums, unions and type aliases, e.g. `std::option::Option<u32>`
1145    ResolvedPath(Path),
1146    /// Dynamic trait object type (`dyn Trait`).
1147    DynTrait(DynTrait),
1148    /// Parameterized types. The contained string is the name of the parameter.
1149    Generic(String),
1150    /// Built-in numeric types (e.g. `u32`, `f32`), `bool`, `char`.
1151    Primitive(String),
1152    /// A function pointer type, e.g. `fn(u32) -> u32`, `extern "C" fn() -> *const u8`
1153    FunctionPointer(Box<FunctionPointer>),
1154    /// A tuple type, e.g. `(String, u32, Box<usize>)`
1155    Tuple(Vec<Type>),
1156    /// An unsized slice type, e.g. `[u32]`.
1157    Slice(Box<Type>),
1158    /// An array type, e.g. `[u32; 15]`
1159    Array {
1160        /// The type of the contained element.
1161        #[serde(rename = "type")]
1162        type_: Box<Type>,
1163        /// The stringified expression that is the length of the array.
1164        ///
1165        /// Keep in mind that it's not guaranteed to match the actual source code of the expression.
1166        len: String,
1167    },
1168    /// A pattern type, e.g. `u32 is 1..`
1169    ///
1170    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/123646)
1171    Pat {
1172        /// The base type, e.g. the `u32` in `u32 is 1..`
1173        #[serde(rename = "type")]
1174        type_: Box<Type>,
1175        #[doc(hidden)]
1176        __pat_unstable_do_not_use: String,
1177    },
1178    /// An opaque type that satisfies a set of bounds, `impl TraitA + TraitB + ...`
1179    ImplTrait(Vec<GenericBound>),
1180    /// A type that's left to be inferred, `_`
1181    Infer,
1182    /// A raw pointer type, e.g. `*mut u32`, `*const u8`, etc.
1183    RawPointer {
1184        /// This is `true` for `*mut _` and `false` for `*const _`.
1185        is_mutable: bool,
1186        /// The type of the pointee.
1187        #[serde(rename = "type")]
1188        type_: Box<Type>,
1189    },
1190    /// `&'a mut String`, `&str`, etc.
1191    BorrowedRef {
1192        /// The name of the lifetime of the reference, if provided.
1193        lifetime: Option<String>,
1194        /// This is `true` for `&mut i32` and `false` for `&i32`
1195        is_mutable: bool,
1196        /// The type of the pointee, e.g. the `i32` in `&'a mut i32`
1197        #[serde(rename = "type")]
1198        type_: Box<Type>,
1199    },
1200    /// Associated types like `<Type as Trait>::Name` and `T::Item` where
1201    /// `T: Iterator` or inherent associated types like `Struct::Name`.
1202    QualifiedPath {
1203        /// The name of the associated type in the parent type.
1204        ///
1205        /// ```ignore (incomplete expression)
1206        /// <core::array::IntoIter<u32, 42> as Iterator>::Item
1207        /// //                                            ^^^^
1208        /// ```
1209        name: String,
1210        /// The generic arguments provided to the associated type.
1211        ///
1212        /// ```ignore (incomplete expression)
1213        /// <core::slice::IterMut<'static, u32> as BetterIterator>::Item<'static>
1214        /// //                                                          ^^^^^^^^^
1215        /// ```
1216        args: Option<Box<GenericArgs>>,
1217        /// The type with which this type is associated.
1218        ///
1219        /// ```ignore (incomplete expression)
1220        /// <core::array::IntoIter<u32, 42> as Iterator>::Item
1221        /// // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1222        /// ```
1223        self_type: Box<Type>,
1224        /// `None` iff this is an *inherent* associated type.
1225        #[serde(rename = "trait")]
1226        trait_: Option<Path>,
1227    },
1228}
1229
1230/// A type that has a simple path to it. This is the kind of type of structs, unions, enums, etc.
1231#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1232pub struct Path {
1233    /// The path of the type.
1234    ///
1235    /// This will be the path that is *used* (not where it is defined), so
1236    /// multiple `Path`s may have different values for this field even if
1237    /// they all refer to the same item. e.g.
1238    ///
1239    /// ```rust
1240    /// pub type Vec1 = std::vec::Vec<i32>; // path: "std::vec::Vec"
1241    /// pub type Vec2 = Vec<i32>; // path: "Vec"
1242    /// pub type Vec3 = std::prelude::v1::Vec<i32>; // path: "std::prelude::v1::Vec"
1243    /// ```
1244    //
1245    // Example tested in ./tests/rustdoc-json/path_name.rs
1246    pub path: String,
1247    /// The ID of the type.
1248    pub id: Id,
1249    /// Generic arguments to the type.
1250    ///
1251    /// ```ignore (incomplete expression)
1252    /// std::borrow::Cow<'static, str>
1253    /// //              ^^^^^^^^^^^^^^
1254    /// ```
1255    pub args: Option<Box<GenericArgs>>,
1256}
1257
1258/// A type that is a function pointer.
1259#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1260pub struct FunctionPointer {
1261    /// The signature of the function.
1262    pub sig: FunctionSignature,
1263    /// Used for Higher-Rank Trait Bounds (HRTBs)
1264    ///
1265    /// ```ignore (incomplete expression)
1266    ///    for<'c> fn(val: &'c i32) -> i32
1267    /// // ^^^^^^^
1268    /// ```
1269    pub generic_params: Vec<GenericParamDef>,
1270    /// The core properties of the function, such as the ABI it conforms to, whether it's unsafe, etc.
1271    pub header: FunctionHeader,
1272}
1273
1274/// The signature of a function.
1275#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1276pub struct FunctionSignature {
1277    /// List of argument names and their type.
1278    ///
1279    /// Note that not all names will be valid identifiers, as some of
1280    /// them may be patterns.
1281    pub inputs: Vec<(String, Type)>,
1282    /// The output type, if specified.
1283    pub output: Option<Type>,
1284    /// Whether the function accepts an arbitrary amount of trailing arguments the C way.
1285    ///
1286    /// ```ignore (incomplete code)
1287    /// fn printf(fmt: &str, ...);
1288    /// ```
1289    pub is_c_variadic: bool,
1290}
1291
1292/// A `trait` declaration.
1293#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1294pub struct Trait {
1295    /// Whether the trait is marked `auto` and is thus implemented automatically
1296    /// for all applicable types.
1297    pub is_auto: bool,
1298    /// Whether the trait is marked as `unsafe`.
1299    pub is_unsafe: bool,
1300    /// Whether the trait is [dyn compatible](https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility)[^1].
1301    ///
1302    /// [^1]: Formerly known as "object safe".
1303    pub is_dyn_compatible: bool,
1304    /// Associated [`Item`]s that can/must be implemented by the `impl` blocks.
1305    pub items: Vec<Id>,
1306    /// Information about the type parameters and `where` clauses of the trait.
1307    pub generics: Generics,
1308    /// Constraints that must be met by the implementor of the trait.
1309    pub bounds: Vec<GenericBound>,
1310    /// The implementations of the trait.
1311    pub implementations: Vec<Id>,
1312}
1313
1314/// A trait alias declaration, e.g. `trait Int = Add + Sub + Mul + Div;`
1315///
1316/// See [the tracking issue](https://github.com/rust-lang/rust/issues/41517)
1317#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1318pub struct TraitAlias {
1319    /// Information about the type parameters and `where` clauses of the alias.
1320    pub generics: Generics,
1321    /// The bounds that are associated with the alias.
1322    pub params: Vec<GenericBound>,
1323}
1324
1325/// An `impl` block.
1326#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1327pub struct Impl {
1328    /// Whether this impl is for an unsafe trait.
1329    pub is_unsafe: bool,
1330    /// Information about the impl’s type parameters and `where` clauses.
1331    pub generics: Generics,
1332    /// The list of the names of all the trait methods that weren't mentioned in this impl but
1333    /// were provided by the trait itself.
1334    ///
1335    /// For example, for this impl of the [`PartialEq`] trait:
1336    /// ```rust
1337    /// struct Foo;
1338    ///
1339    /// impl PartialEq for Foo {
1340    ///     fn eq(&self, other: &Self) -> bool { todo!() }
1341    /// }
1342    /// ```
1343    /// This field will be `["ne"]`, as it has a default implementation defined for it.
1344    pub provided_trait_methods: Vec<String>,
1345    /// The trait being implemented or `None` if the impl is inherent, which means
1346    /// `impl Struct {}` as opposed to `impl Trait for Struct {}`.
1347    #[serde(rename = "trait")]
1348    pub trait_: Option<Path>,
1349    /// The type that the impl block is for.
1350    #[serde(rename = "for")]
1351    pub for_: Type,
1352    /// The list of associated items contained in this impl block.
1353    pub items: Vec<Id>,
1354    /// Whether this is a negative impl (e.g. `!Sized` or `!Send`).
1355    pub is_negative: bool,
1356    /// Whether this is an impl that’s implied by the compiler
1357    /// (for autotraits, e.g. `Send` or `Sync`).
1358    pub is_synthetic: bool,
1359    // FIXME: document this
1360    pub blanket_impl: Option<Type>,
1361}
1362
1363/// A `use` statement.
1364#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1365#[serde(rename_all = "snake_case")]
1366pub struct Use {
1367    /// The full path being imported.
1368    pub source: String,
1369    /// May be different from the last segment of `source` when renaming imports:
1370    /// `use source as name;`
1371    pub name: String,
1372    /// The ID of the item being imported. Will be `None` in case of re-exports of primitives:
1373    /// ```rust
1374    /// pub use i32 as my_i32;
1375    /// ```
1376    pub id: Option<Id>,
1377    /// Whether this statement is a wildcard `use`, e.g. `use source::*;`
1378    pub is_glob: bool,
1379}
1380
1381/// A procedural macro.
1382#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1383pub struct ProcMacro {
1384    /// How this macro is supposed to be called: `foo!()`, `#[foo]` or `#[derive(foo)]`
1385    pub kind: MacroKind,
1386    /// Helper attributes defined by a macro to be used inside it.
1387    ///
1388    /// Defined only for derive macros.
1389    ///
1390    /// E.g. the [`Default`] derive macro defines a `#[default]` helper attribute so that one can
1391    /// do:
1392    ///
1393    /// ```rust
1394    /// #[derive(Default)]
1395    /// enum Option<T> {
1396    ///     #[default]
1397    ///     None,
1398    ///     Some(T),
1399    /// }
1400    /// ```
1401    pub helpers: Vec<String>,
1402}
1403
1404/// The way a [`ProcMacro`] is declared to be used.
1405#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1406#[serde(rename_all = "snake_case")]
1407pub enum MacroKind {
1408    /// A bang macro `foo!()`.
1409    Bang,
1410    /// An attribute macro `#[foo]`.
1411    Attr,
1412    /// A derive macro `#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]`
1413    Derive,
1414}
1415
1416/// A type alias declaration, e.g. `type Pig = std::borrow::Cow<'static, str>;`
1417#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1418pub struct TypeAlias {
1419    /// The type referred to by this alias.
1420    #[serde(rename = "type")]
1421    pub type_: Type,
1422    /// Information about the type parameters and `where` clauses of the alias.
1423    pub generics: Generics,
1424}
1425
1426/// A `static` declaration.
1427#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1428pub struct Static {
1429    /// The type of the static.
1430    #[serde(rename = "type")]
1431    pub type_: Type,
1432    /// This is `true` for mutable statics, declared as `static mut X: T = f();`
1433    pub is_mutable: bool,
1434    /// The stringified expression for the initial value.
1435    ///
1436    /// It's not guaranteed that it'll match the actual source code for the initial value.
1437    pub expr: String,
1438
1439    /// Is the static `unsafe`?
1440    ///
1441    /// This is only true if it's in an `extern` block, and not explicitly marked
1442    /// as `safe`.
1443    ///
1444    /// ```rust
1445    /// unsafe extern {
1446    ///     static A: i32;      // unsafe
1447    ///     safe static B: i32; // safe
1448    /// }
1449    ///
1450    /// static C: i32 = 0;     // safe
1451    /// static mut D: i32 = 0; // safe
1452    /// ```
1453    pub is_unsafe: bool,
1454}
1455
1456/// A primitive type declaration. Declarations of this kind can only come from the core library.
1457#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1458pub struct Primitive {
1459    /// The name of the type.
1460    pub name: String,
1461    /// The implementations, inherent and of traits, on the primitive type.
1462    pub impls: Vec<Id>,
1463}
1464
1465#[cfg(test)]
1466mod tests;