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