rustdoc_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
26
27/// The version of JSON output that this crate represents.
28///
29/// This integer is incremented with every breaking change to the API,
30/// and is returned along with the JSON blob as [`Crate::format_version`].
31/// Consuming code should assert that this value matches the format version(s) that it supports.
32//
33// WARNING: When you update `FORMAT_VERSION`, please also update the "Latest feature" line with a
34// description of the change. This minimizes the risk of two concurrent PRs changing
35// `FORMAT_VERSION` from N to N+1 and git merging them without conflicts; the "Latest feature" line
36// will instead cause conflicts. See #94591 for more. (This paragraph and the "Latest feature" line
37// are deliberately not in a doc comment, because they need not be in public docs.)
38//
39// Latest feature: Structured Attributes
40pub const FORMAT_VERSION: u32 = 54;
41
42/// The root of the emitted JSON blob.
43///
44/// It contains all type/documentation information
45/// about the language items in the local crate, as well as info about external items to allow
46/// tools to find or link to them.
47#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
48pub struct Crate {
49    /// The id of the root [`Module`] item of the local crate.
50    pub root: Id,
51    /// The version string given to `--crate-version`, if any.
52    pub crate_version: Option<String>,
53    /// Whether or not the output includes private items.
54    pub includes_private: bool,
55    /// A collection of all items in the local crate as well as some external traits and their
56    /// items that are referenced locally.
57    pub index: HashMap<Id, Item>,
58    /// Maps IDs to fully qualified paths and other info helpful for generating links.
59    pub paths: HashMap<Id, ItemSummary>,
60    /// Maps `crate_id` of items to a crate name and html_root_url if it exists.
61    pub external_crates: HashMap<u32, ExternalCrate>,
62    /// Information about the target for which this documentation was generated
63    pub target: Target,
64    /// A single version number to be used in the future when making backwards incompatible changes
65    /// to the JSON output.
66    pub format_version: u32,
67}
68
69/// Information about a target
70#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
71pub struct Target {
72    /// The target triple for which this documentation was generated
73    pub triple: String,
74    /// A list of features valid for use in `#[target_feature]` attributes
75    /// for the target where this rustdoc JSON was generated.
76    pub target_features: Vec<TargetFeature>,
77}
78
79/// Information about a target feature.
80///
81/// Rust target features are used to influence code generation, especially around selecting
82/// instructions which are not universally supported by the target architecture.
83///
84/// Target features are commonly enabled by the [`#[target_feature]` attribute][1] to influence code
85/// generation for a particular function, and less commonly enabled by compiler options like
86/// `-Ctarget-feature` or `-Ctarget-cpu`. Targets themselves automatically enable certain target
87/// features by default, for example because the target's ABI specification requires saving specific
88/// registers which only exist in an architectural extension.
89///
90/// Target features can imply other target features: for example, x86-64 `avx2` implies `avx`, and
91/// aarch64 `sve2` implies `sve`, since both of these architectural extensions depend on their
92/// predecessors.
93///
94/// Target features can be probed at compile time by [`#[cfg(target_feature)]`][2] or `cfg!(…)`
95/// conditional compilation to determine whether a target feature is enabled in a particular
96/// context.
97///
98/// [1]: https://doc.rust-lang.org/stable/reference/attributes/codegen.html#the-target_feature-attribute
99/// [2]: https://doc.rust-lang.org/reference/conditional-compilation.html#target_feature
100#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
101pub struct TargetFeature {
102    /// The name of this target feature.
103    pub name: String,
104    /// Other target features which are implied by this target feature, if any.
105    pub implies_features: Vec<String>,
106    /// If this target feature is unstable, the name of the associated language feature gate.
107    pub unstable_feature_gate: Option<String>,
108    /// Whether this feature is globally enabled for this compilation session.
109    ///
110    /// Target features can be globally enabled implicitly as a result of the target's definition.
111    /// For example, x86-64 hardware floating point ABIs require saving x87 and SSE2 registers,
112    /// which in turn requires globally enabling the `x87` and `sse2` target features so that the
113    /// generated machine code conforms to the target's ABI.
114    ///
115    /// Target features can also be globally enabled explicitly as a result of compiler flags like
116    /// [`-Ctarget-feature`][1] or [`-Ctarget-cpu`][2].
117    ///
118    /// [1]: https://doc.rust-lang.org/beta/rustc/codegen-options/index.html#target-feature
119    /// [2]: https://doc.rust-lang.org/beta/rustc/codegen-options/index.html#target-cpu
120    pub globally_enabled: bool,
121}
122
123/// Metadata of a crate, either the same crate on which `rustdoc` was invoked, or its dependency.
124#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
125pub struct ExternalCrate {
126    /// The name of the crate.
127    ///
128    /// Note: This is the [*crate* name][crate-name], which may not be the same as the
129    /// [*package* name][package-name]. For example, for <https://crates.io/crates/regex-syntax>,
130    /// this field will be `regex_syntax` (which uses an `_`, not a `-`).
131    ///
132    /// [crate-name]: https://doc.rust-lang.org/stable/cargo/reference/cargo-targets.html#the-name-field
133    /// [package-name]: https://doc.rust-lang.org/stable/cargo/reference/manifest.html#the-name-field
134    pub name: String,
135    /// The root URL at which the crate's documentation lives.
136    pub html_root_url: Option<String>,
137}
138
139/// Information about an external (not defined in the local crate) [`Item`].
140///
141/// For external items, you don't get the same level of
142/// information. This struct should contain enough to generate a link/reference to the item in
143/// question, or can be used by a tool that takes the json output of multiple crates to find
144/// the actual item definition with all the relevant info.
145#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
146pub struct ItemSummary {
147    /// Can be used to look up the name and html_root_url of the crate this item came from in the
148    /// `external_crates` map.
149    pub crate_id: u32,
150    /// The list of path components for the fully qualified path of this item (e.g.
151    /// `["std", "io", "lazy", "Lazy"]` for `std::io::lazy::Lazy`).
152    ///
153    /// Note that items can appear in multiple paths, and the one chosen is implementation
154    /// defined. Currently, this is the full path to where the item was defined. Eg
155    /// [`String`] is currently `["alloc", "string", "String"]` and [`HashMap`][`std::collections::HashMap`]
156    /// is `["std", "collections", "hash", "map", "HashMap"]`, but this is subject to change.
157    pub path: Vec<String>,
158    /// Whether this item is a struct, trait, macro, etc.
159    pub kind: ItemKind,
160}
161
162/// Anything that can hold documentation - modules, structs, enums, functions, traits, etc.
163///
164/// The `Item` data type holds fields that can apply to any of these,
165/// and leaves kind-specific details (like function args or enum variants) to the `inner` field.
166#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
167pub struct Item {
168    /// The unique identifier of this item. Can be used to find this item in various mappings.
169    pub id: Id,
170    /// This can be used as a key to the `external_crates` map of [`Crate`] to see which crate
171    /// this item came from.
172    pub crate_id: u32,
173    /// Some items such as impls don't have names.
174    pub name: Option<String>,
175    /// The source location of this item (absent if it came from a macro expansion or inline
176    /// assembly).
177    pub span: Option<Span>,
178    /// By default all documented items are public, but you can tell rustdoc to output private items
179    /// so this field is needed to differentiate.
180    pub visibility: Visibility,
181    /// The full markdown docstring of this item. Absent if there is no documentation at all,
182    /// Some("") if there is some documentation but it is empty (EG `#[doc = ""]`).
183    pub docs: Option<String>,
184    /// 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
185    pub links: HashMap<String, Id>,
186    /// Attributes on this item.
187    ///
188    /// Does not include `#[deprecated]` attributes: see the [`Self::deprecation`] field instead.
189    ///
190    /// Attributes appear in pretty-printed Rust form, regardless of their formatting
191    /// in the original source code. For example:
192    /// - `#[non_exhaustive]` and `#[must_use]` are represented as themselves.
193    /// - `#[no_mangle]` and `#[export_name]` are also represented as themselves.
194    /// - `#[repr(C)]` and other reprs also appear as themselves,
195    ///   though potentially with a different order: e.g. `repr(i8, C)` may become `repr(C, i8)`.
196    ///   Multiple repr attributes on the same item may be combined into an equivalent single attr.
197    pub attrs: Vec<Attribute>,
198    /// Information about the item’s deprecation, if present.
199    pub deprecation: Option<Deprecation>,
200    /// The type-specific fields describing this item.
201    pub inner: ItemEnum,
202}
203
204#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
205#[serde(rename_all = "snake_case")]
206/// An attribute, e.g. `#[repr(C)]`
207///
208/// This doesn't include:
209/// - `#[doc = "Doc Comment"]` or `/// Doc comment`. These are in [`Item::docs`] instead.
210/// - `#[deprecated]`. These are in [`Item::deprecation`] instead.
211pub enum Attribute {
212    /// `#[non_exhaustive]`
213    NonExhaustive,
214
215    /// `#[must_use]`
216    MustUse { reason: Option<String> },
217
218    /// `#[export_name = "name"]`
219    ExportName(String),
220
221    /// `#[link_section = "name"]`
222    LinkSection(String),
223
224    /// `#[automatically_derived]`
225    AutomaticallyDerived,
226
227    /// `#[repr]`
228    Repr(AttributeRepr),
229
230    /// `#[no_mangle]`
231    NoMangle,
232
233    /// #[target_feature(enable = "feature1", enable = "feature2")]
234    TargetFeature { enable: Vec<String> },
235
236    /// Something else.
237    ///
238    /// Things here are explicitly *not* covered by the [`FORMAT_VERSION`]
239    /// constant, and may change without bumping the format version.
240    ///
241    /// As an implementation detail, this is currently either:
242    /// 1. A HIR debug printing, like `"#[attr = Optimize(Speed)]"`
243    /// 2. The attribute as it appears in source form, like
244    ///    `"#[optimize(speed)]"`.
245    Other(String),
246}
247
248#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
249/// The contents of a `#[repr(...)]` attribute.
250///
251/// Used in [`Attribute::Repr`].
252pub struct AttributeRepr {
253    /// The representation, e.g. `#[repr(C)]`, `#[repr(transparent)]`
254    pub kind: ReprKind,
255
256    /// Alignment in bytes, if explicitly specified by `#[repr(align(...)]`.
257    pub align: Option<u64>,
258    /// Alignment in bytes, if explicitly specified by `#[repr(packed(...)]]`.
259    pub packed: Option<u64>,
260
261    /// The integer type for an enum descriminant, if explicitly specified.
262    ///
263    /// e.g. `"i32"`, for `#[repr(C, i32)]`
264    pub int: Option<String>,
265}
266
267#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
268#[serde(rename_all = "snake_case")]
269/// The kind of `#[repr]`.
270///
271/// See [AttributeRepr::kind]`.
272pub enum ReprKind {
273    /// `#[repr(Rust)]`
274    ///
275    /// Also the default.
276    Rust,
277    /// `#[repr(C)]`
278    C,
279    /// `#[repr(transparent)]
280    Transparent,
281    /// `#[repr(simd)]`
282    Simd,
283}
284
285/// A range of source code.
286#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
287pub struct Span {
288    /// The path to the source file for this span relative to the path `rustdoc` was invoked with.
289    pub filename: PathBuf,
290    /// One indexed Line and Column of the first character of the `Span`.
291    pub begin: (usize, usize),
292    /// One indexed Line and Column of the last character of the `Span`.
293    pub end: (usize, usize),
294}
295
296/// Information about the deprecation of an [`Item`].
297#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
298pub struct Deprecation {
299    /// Usually a version number when this [`Item`] first became deprecated.
300    pub since: Option<String>,
301    /// The reason for deprecation and/or what alternatives to use.
302    pub note: Option<String>,
303}
304
305/// Visibility of an [`Item`].
306#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
307#[serde(rename_all = "snake_case")]
308pub enum Visibility {
309    /// Explicitly public visibility set with `pub`.
310    Public,
311    /// For the most part items are private by default. The exceptions are associated items of
312    /// public traits and variants of public enums.
313    Default,
314    /// Explicitly crate-wide visibility set with `pub(crate)`
315    Crate,
316    /// For `pub(in path)` visibility.
317    Restricted {
318        /// ID of the module to which this visibility restricts items.
319        parent: Id,
320        /// The path with which [`parent`] was referenced
321        /// (like `super::super` or `crate::foo::bar`).
322        ///
323        /// [`parent`]: Visibility::Restricted::parent
324        path: String,
325    },
326}
327
328/// Dynamic trait object type (`dyn Trait`).
329#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
330pub struct DynTrait {
331    /// All the traits implemented. One of them is the vtable, and the rest must be auto traits.
332    pub traits: Vec<PolyTrait>,
333    /// The lifetime of the whole dyn object
334    /// ```text
335    /// dyn Debug + 'static
336    ///             ^^^^^^^
337    ///             |
338    ///             this part
339    /// ```
340    pub lifetime: Option<String>,
341}
342
343/// A trait and potential HRTBs
344#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
345pub struct PolyTrait {
346    /// The path to the trait.
347    #[serde(rename = "trait")]
348    pub trait_: Path,
349    /// Used for Higher-Rank Trait Bounds (HRTBs)
350    /// ```text
351    /// dyn for<'a> Fn() -> &'a i32"
352    ///     ^^^^^^^
353    /// ```
354    pub generic_params: Vec<GenericParamDef>,
355}
356
357/// A set of generic arguments provided to a path segment, e.g.
358///
359/// ```text
360/// std::option::Option<u32>
361///                    ^^^^^
362/// ```
363#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
364#[serde(rename_all = "snake_case")]
365pub enum GenericArgs {
366    /// `<'a, 32, B: Copy, C = u32>`
367    AngleBracketed {
368        /// The list of each argument on this type.
369        /// ```text
370        /// <'a, 32, B: Copy, C = u32>
371        ///  ^^^^^^
372        /// ```
373        args: Vec<GenericArg>,
374        /// Associated type or constant bindings (e.g. `Item=i32` or `Item: Clone`) for this type.
375        constraints: Vec<AssocItemConstraint>,
376    },
377    /// `Fn(A, B) -> C`
378    Parenthesized {
379        /// The input types, enclosed in parentheses.
380        inputs: Vec<Type>,
381        /// The output type provided after the `->`, if present.
382        output: Option<Type>,
383    },
384    /// `T::method(..)`
385    ReturnTypeNotation,
386}
387
388/// One argument in a list of generic arguments to a path segment.
389///
390/// Part of [`GenericArgs`].
391#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
392#[serde(rename_all = "snake_case")]
393pub enum GenericArg {
394    /// A lifetime argument.
395    /// ```text
396    /// std::borrow::Cow<'static, str>
397    ///                  ^^^^^^^
398    /// ```
399    Lifetime(String),
400    /// A type argument.
401    /// ```text
402    /// std::borrow::Cow<'static, str>
403    ///                           ^^^
404    /// ```
405    Type(Type),
406    /// A constant as a generic argument.
407    /// ```text
408    /// core::array::IntoIter<u32, { 640 * 1024 }>
409    ///                            ^^^^^^^^^^^^^^
410    /// ```
411    Const(Constant),
412    /// A generic argument that's explicitly set to be inferred.
413    /// ```text
414    /// std::vec::Vec::<_>
415    ///                 ^
416    /// ```
417    Infer,
418}
419
420/// A constant.
421#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
422pub struct Constant {
423    /// The stringified expression of this constant. Note that its mapping to the original
424    /// source code is unstable and it's not guaranteed that it'll match the source code.
425    pub expr: String,
426    /// The value of the evaluated expression for this constant, which is only computed for numeric
427    /// types.
428    pub value: Option<String>,
429    /// Whether this constant is a bool, numeric, string, or char literal.
430    pub is_literal: bool,
431}
432
433/// Describes a bound applied to an associated type/constant.
434///
435/// Example:
436/// ```text
437/// IntoIterator<Item = u32, IntoIter: Clone>
438///              ^^^^^^^^^^  ^^^^^^^^^^^^^^^
439/// ```
440#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
441pub struct AssocItemConstraint {
442    /// The name of the associated type/constant.
443    pub name: String,
444    /// Arguments provided to the associated type/constant.
445    pub args: Option<Box<GenericArgs>>,
446    /// The kind of bound applied to the associated type/constant.
447    pub binding: AssocItemConstraintKind,
448}
449
450/// The way in which an associate type/constant is bound.
451#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
452#[serde(rename_all = "snake_case")]
453pub enum AssocItemConstraintKind {
454    /// The required value/type is specified exactly. e.g.
455    /// ```text
456    /// Iterator<Item = u32, IntoIter: DoubleEndedIterator>
457    ///          ^^^^^^^^^^
458    /// ```
459    Equality(Term),
460    /// The type is required to satisfy a set of bounds.
461    /// ```text
462    /// Iterator<Item = u32, IntoIter: DoubleEndedIterator>
463    ///                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
464    /// ```
465    Constraint(Vec<GenericBound>),
466}
467
468/// An opaque identifier for an item.
469///
470/// It can be used to lookup in [`Crate::index`] or [`Crate::paths`] to resolve it
471/// to an [`Item`].
472///
473/// Id's are only valid within a single JSON blob. They cannot be used to
474/// resolve references between the JSON output's for different crates.
475///
476/// Rustdoc makes no guarantees about the inner value of Id's. Applications
477/// should treat them as opaque keys to lookup items, and avoid attempting
478/// to parse them, or otherwise depend on any implementation details.
479#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
480// FIXME(aDotInTheVoid): Consider making this non-public in rustdoc-types.
481pub struct Id(pub u32);
482
483/// The fundamental kind of an item. Unlike [`ItemEnum`], this does not carry any additional info.
484///
485/// Part of [`ItemSummary`].
486#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
487#[serde(rename_all = "snake_case")]
488pub enum ItemKind {
489    /// A module declaration, e.g. `mod foo;` or `mod foo {}`
490    Module,
491    /// A crate imported via the `extern crate` syntax.
492    ExternCrate,
493    /// An import of 1 or more items into scope, using the `use` keyword.
494    Use,
495    /// A `struct` declaration.
496    Struct,
497    /// A field of a struct.
498    StructField,
499    /// A `union` declaration.
500    Union,
501    /// An `enum` declaration.
502    Enum,
503    /// A variant of a enum.
504    Variant,
505    /// A function declaration, e.g. `fn f() {}`
506    Function,
507    /// A type alias declaration, e.g. `type Pig = std::borrow::Cow<'static, str>;`
508    TypeAlias,
509    /// The declaration of a constant, e.g. `const GREETING: &str = "Hi :3";`
510    Constant,
511    /// A `trait` declaration.
512    Trait,
513    /// A trait alias declaration, e.g. `trait Int = Add + Sub + Mul + Div;`
514    ///
515    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/41517)
516    TraitAlias,
517    /// An `impl` block.
518    Impl,
519    /// A `static` declaration.
520    Static,
521    /// `type`s from an `extern` block.
522    ///
523    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/43467)
524    ExternType,
525    /// A macro declaration.
526    ///
527    /// Corresponds to either `ItemEnum::Macro(_)`
528    /// or `ItemEnum::ProcMacro(ProcMacro { kind: MacroKind::Bang })`
529    Macro,
530    /// A procedural macro attribute.
531    ///
532    /// Corresponds to `ItemEnum::ProcMacro(ProcMacro { kind: MacroKind::Attr })`
533    ProcAttribute,
534    /// A procedural macro usable in the `#[derive()]` attribute.
535    ///
536    /// Corresponds to `ItemEnum::ProcMacro(ProcMacro { kind: MacroKind::Derive })`
537    ProcDerive,
538    /// An associated constant of a trait or a type.
539    AssocConst,
540    /// An associated type of a trait or a type.
541    AssocType,
542    /// A primitive type, e.g. `u32`.
543    ///
544    /// [`Item`]s of this kind only come from the core library.
545    Primitive,
546    /// A keyword declaration.
547    ///
548    /// [`Item`]s of this kind only come from the come library and exist solely
549    /// to carry documentation for the respective keywords.
550    Keyword,
551}
552
553/// Specific fields of an item.
554///
555/// Part of [`Item`].
556#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
557#[serde(rename_all = "snake_case")]
558pub enum ItemEnum {
559    /// A module declaration, e.g. `mod foo;` or `mod foo {}`
560    Module(Module),
561    /// A crate imported via the `extern crate` syntax.
562    ExternCrate {
563        /// The name of the imported crate.
564        name: String,
565        /// If the crate is renamed, this is its name in the crate.
566        rename: Option<String>,
567    },
568    /// An import of 1 or more items into scope, using the `use` keyword.
569    Use(Use),
570
571    /// A `union` declaration.
572    Union(Union),
573    /// A `struct` declaration.
574    Struct(Struct),
575    /// A field of a struct.
576    StructField(Type),
577    /// An `enum` declaration.
578    Enum(Enum),
579    /// A variant of a enum.
580    Variant(Variant),
581
582    /// A function declaration (including methods and other associated functions)
583    Function(Function),
584
585    /// A `trait` declaration.
586    Trait(Trait),
587    /// A trait alias declaration, e.g. `trait Int = Add + Sub + Mul + Div;`
588    ///
589    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/41517)
590    TraitAlias(TraitAlias),
591    /// An `impl` block.
592    Impl(Impl),
593
594    /// A type alias declaration, e.g. `type Pig = std::borrow::Cow<'static, str>;`
595    TypeAlias(TypeAlias),
596    /// The declaration of a constant, e.g. `const GREETING: &str = "Hi :3";`
597    Constant {
598        /// The type of the constant.
599        #[serde(rename = "type")]
600        type_: Type,
601        /// The declared constant itself.
602        #[serde(rename = "const")]
603        const_: Constant,
604    },
605
606    /// A declaration of a `static`.
607    Static(Static),
608
609    /// `type`s from an `extern` block.
610    ///
611    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/43467)
612    ExternType,
613
614    /// A macro_rules! declarative macro. Contains a single string with the source
615    /// representation of the macro with the patterns stripped.
616    Macro(String),
617    /// A procedural macro.
618    ProcMacro(ProcMacro),
619
620    /// A primitive type, e.g. `u32`.
621    ///
622    /// [`Item`]s of this kind only come from the core library.
623    Primitive(Primitive),
624
625    /// An associated constant of a trait or a type.
626    AssocConst {
627        /// The type of the constant.
628        #[serde(rename = "type")]
629        type_: Type,
630        /// Inside a trait declaration, this is the default value for the associated constant,
631        /// if provided.
632        /// Inside an `impl` block, this is the value assigned to the associated constant,
633        /// and will always be present.
634        ///
635        /// The representation is implementation-defined and not guaranteed to be representative of
636        /// either the resulting value or of the source code.
637        ///
638        /// ```rust
639        /// const X: usize = 640 * 1024;
640        /// //               ^^^^^^^^^^
641        /// ```
642        value: Option<String>,
643    },
644    /// An associated type of a trait or a type.
645    AssocType {
646        /// The generic parameters and where clauses on ahis associated type.
647        generics: Generics,
648        /// The bounds for this associated type. e.g.
649        /// ```rust
650        /// trait IntoIterator {
651        ///     type Item;
652        ///     type IntoIter: Iterator<Item = Self::Item>;
653        /// //                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
654        /// }
655        /// ```
656        bounds: Vec<GenericBound>,
657        /// Inside a trait declaration, this is the default for the associated type, if provided.
658        /// Inside an impl block, this is the type assigned to the associated type, and will always
659        /// be present.
660        ///
661        /// ```rust
662        /// type X = usize;
663        /// //       ^^^^^
664        /// ```
665        #[serde(rename = "type")]
666        type_: Option<Type>,
667    },
668}
669
670/// A module declaration, e.g. `mod foo;` or `mod foo {}`.
671#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
672pub struct Module {
673    /// Whether this is the root item of a crate.
674    ///
675    /// This item doesn't correspond to any construction in the source code and is generated by the
676    /// compiler.
677    pub is_crate: bool,
678    /// [`Item`]s declared inside this module.
679    pub items: Vec<Id>,
680    /// If `true`, this module is not part of the public API, but it contains
681    /// items that are re-exported as public API.
682    pub is_stripped: bool,
683}
684
685/// A `union`.
686#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
687pub struct Union {
688    /// The generic parameters and where clauses on this union.
689    pub generics: Generics,
690    /// Whether any fields have been removed from the result, due to being private or hidden.
691    pub has_stripped_fields: bool,
692    /// The list of fields in the union.
693    ///
694    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::StructField`].
695    pub fields: Vec<Id>,
696    /// All impls (both of traits and inherent) for this union.
697    ///
698    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Impl`].
699    pub impls: Vec<Id>,
700}
701
702/// A `struct`.
703#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
704pub struct Struct {
705    /// The kind of the struct (e.g. unit, tuple-like or struct-like) and the data specific to it,
706    /// i.e. fields.
707    pub kind: StructKind,
708    /// The generic parameters and where clauses on this struct.
709    pub generics: Generics,
710    /// All impls (both of traits and inherent) for this struct.
711    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Impl`].
712    pub impls: Vec<Id>,
713}
714
715/// The kind of a [`Struct`] and the data specific to it, i.e. fields.
716#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
717#[serde(rename_all = "snake_case")]
718pub enum StructKind {
719    /// A struct with no fields and no parentheses.
720    ///
721    /// ```rust
722    /// pub struct Unit;
723    /// ```
724    Unit,
725    /// A struct with unnamed fields.
726    ///
727    /// All [`Id`]'s will point to [`ItemEnum::StructField`].
728    /// Unlike most of JSON, private and `#[doc(hidden)]` fields will be given as `None`
729    /// instead of being omitted, because order matters.
730    ///
731    /// ```rust
732    /// pub struct TupleStruct(i32);
733    /// pub struct EmptyTupleStruct();
734    /// ```
735    Tuple(Vec<Option<Id>>),
736    /// A struct with named fields.
737    ///
738    /// ```rust
739    /// pub struct PlainStruct { x: i32 }
740    /// pub struct EmptyPlainStruct {}
741    /// ```
742    Plain {
743        /// The list of fields in the struct.
744        ///
745        /// All of the corresponding [`Item`]s are of kind [`ItemEnum::StructField`].
746        fields: Vec<Id>,
747        /// Whether any fields have been removed from the result, due to being private or hidden.
748        has_stripped_fields: bool,
749    },
750}
751
752/// An `enum`.
753#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
754pub struct Enum {
755    /// Information about the type parameters and `where` clauses of the enum.
756    pub generics: Generics,
757    /// Whether any variants have been removed from the result, due to being private or hidden.
758    pub has_stripped_variants: bool,
759    /// The list of variants in the enum.
760    ///
761    /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Variant`]
762    pub variants: Vec<Id>,
763    /// `impl`s for the enum.
764    pub impls: Vec<Id>,
765}
766
767/// A variant of an enum.
768#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
769pub struct Variant {
770    /// Whether the variant is plain, a tuple-like, or struct-like. Contains the fields.
771    pub kind: VariantKind,
772    /// The discriminant, if explicitly specified.
773    pub discriminant: Option<Discriminant>,
774}
775
776/// The kind of an [`Enum`] [`Variant`] and the data specific to it, i.e. fields.
777#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
778#[serde(rename_all = "snake_case")]
779pub enum VariantKind {
780    /// A variant with no parentheses
781    ///
782    /// ```rust
783    /// enum Demo {
784    ///     PlainVariant,
785    ///     PlainWithDiscriminant = 1,
786    /// }
787    /// ```
788    Plain,
789    /// A variant with unnamed fields.
790    ///
791    /// All [`Id`]'s will point to [`ItemEnum::StructField`].
792    /// Unlike most of JSON, `#[doc(hidden)]` fields will be given as `None`
793    /// instead of being omitted, because order matters.
794    ///
795    /// ```rust
796    /// enum Demo {
797    ///     TupleVariant(i32),
798    ///     EmptyTupleVariant(),
799    /// }
800    /// ```
801    Tuple(Vec<Option<Id>>),
802    /// A variant with named fields.
803    ///
804    /// ```rust
805    /// enum Demo {
806    ///     StructVariant { x: i32 },
807    ///     EmptyStructVariant {},
808    /// }
809    /// ```
810    Struct {
811        /// The list of variants in the enum.
812        /// All of the corresponding [`Item`]s are of kind [`ItemEnum::Variant`].
813        fields: Vec<Id>,
814        /// Whether any variants have been removed from the result, due to being private or hidden.
815        has_stripped_fields: bool,
816    },
817}
818
819/// The value that distinguishes a variant in an [`Enum`] from other variants.
820#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
821pub struct Discriminant {
822    /// The expression that produced the discriminant.
823    ///
824    /// Unlike `value`, this preserves the original formatting (eg suffixes,
825    /// hexadecimal, and underscores), making it unsuitable to be machine
826    /// interpreted.
827    ///
828    /// In some cases, when the value is too complex, this may be `"{ _ }"`.
829    /// When this occurs is unstable, and may change without notice.
830    pub expr: String,
831    /// The numerical value of the discriminant. Stored as a string due to
832    /// JSON's poor support for large integers, and the fact that it would need
833    /// to store from [`i128::MIN`] to [`u128::MAX`].
834    pub value: String,
835}
836
837/// A set of fundamental properties of a function.
838#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
839pub struct FunctionHeader {
840    /// Is this function marked as `const`?
841    pub is_const: bool,
842    /// Is this function unsafe?
843    pub is_unsafe: bool,
844    /// Is this function async?
845    pub is_async: bool,
846    /// The ABI used by the function.
847    pub abi: Abi,
848}
849
850/// The ABI (Application Binary Interface) used by a function.
851///
852/// If a variant has an `unwind` field, this means the ABI that it represents can be specified in 2
853/// ways: `extern "_"` and `extern "_-unwind"`, and a value of `true` for that field signifies the
854/// latter variant.
855///
856/// See the [Rustonomicon section](https://doc.rust-lang.org/nightly/nomicon/ffi.html#ffi-and-unwinding)
857/// on unwinding for more info.
858#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
859pub enum Abi {
860    // We only have a concrete listing here for stable ABI's because there are so many
861    // See rustc_ast_passes::feature_gate::PostExpansionVisitor::check_abi for the list
862    /// The default ABI, but that can also be written explicitly with `extern "Rust"`.
863    Rust,
864    /// Can be specified as `extern "C"` or, as a shorthand, just `extern`.
865    C { unwind: bool },
866    /// Can be specified as `extern "cdecl"`.
867    Cdecl { unwind: bool },
868    /// Can be specified as `extern "stdcall"`.
869    Stdcall { unwind: bool },
870    /// Can be specified as `extern "fastcall"`.
871    Fastcall { unwind: bool },
872    /// Can be specified as `extern "aapcs"`.
873    Aapcs { unwind: bool },
874    /// Can be specified as `extern "win64"`.
875    Win64 { unwind: bool },
876    /// Can be specified as `extern "sysv64"`.
877    SysV64 { unwind: bool },
878    /// Can be specified as `extern "system"`.
879    System { unwind: bool },
880    /// Any other ABI, including unstable ones.
881    Other(String),
882}
883
884/// A function declaration (including methods and other associated functions).
885#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
886pub struct Function {
887    /// Information about the function signature, or declaration.
888    pub sig: FunctionSignature,
889    /// Information about the function’s type parameters and `where` clauses.
890    pub generics: Generics,
891    /// Information about core properties of the function, e.g. whether it's `const`, its ABI, etc.
892    pub header: FunctionHeader,
893    /// Whether the function has a body, i.e. an implementation.
894    pub has_body: bool,
895}
896
897/// Generic parameters accepted by an item and `where` clauses imposed on it and the parameters.
898#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
899pub struct Generics {
900    /// A list of generic parameter definitions (e.g. `<T: Clone + Hash, U: Copy>`).
901    pub params: Vec<GenericParamDef>,
902    /// A list of where predicates (e.g. `where T: Iterator, T::Item: Copy`).
903    pub where_predicates: Vec<WherePredicate>,
904}
905
906/// One generic parameter accepted by an item.
907#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
908pub struct GenericParamDef {
909    /// Name of the parameter.
910    /// ```rust
911    /// fn f<'resource, Resource>(x: &'resource Resource) {}
912    /// //    ^^^^^^^^  ^^^^^^^^
913    /// ```
914    pub name: String,
915    /// The kind of the parameter and data specific to a particular parameter kind, e.g. type
916    /// bounds.
917    pub kind: GenericParamDefKind,
918}
919
920/// The kind of a [`GenericParamDef`].
921#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
922#[serde(rename_all = "snake_case")]
923pub enum GenericParamDefKind {
924    /// Denotes a lifetime parameter.
925    Lifetime {
926        /// Lifetimes that this lifetime parameter is required to outlive.
927        ///
928        /// ```rust
929        /// fn f<'a, 'b, 'resource: 'a + 'b>(a: &'a str, b: &'b str, res: &'resource str) {}
930        /// //                      ^^^^^^^
931        /// ```
932        outlives: Vec<String>,
933    },
934
935    /// Denotes a type parameter.
936    Type {
937        /// Bounds applied directly to the type. Note that the bounds from `where` clauses
938        /// that constrain this parameter won't appear here.
939        ///
940        /// ```rust
941        /// fn default2<T: Default>() -> [T; 2] where T: Clone { todo!() }
942        /// //             ^^^^^^^
943        /// ```
944        bounds: Vec<GenericBound>,
945        /// The default type for this parameter, if provided, e.g.
946        ///
947        /// ```rust
948        /// trait PartialEq<Rhs = Self> {}
949        /// //                    ^^^^
950        /// ```
951        default: Option<Type>,
952        /// This is normally `false`, which means that this generic parameter is
953        /// declared in the Rust source text.
954        ///
955        /// If it is `true`, this generic parameter has been introduced by the
956        /// compiler behind the scenes.
957        ///
958        /// # Example
959        ///
960        /// Consider
961        ///
962        /// ```ignore (pseudo-rust)
963        /// pub fn f(_: impl Trait) {}
964        /// ```
965        ///
966        /// The compiler will transform this behind the scenes to
967        ///
968        /// ```ignore (pseudo-rust)
969        /// pub fn f<impl Trait: Trait>(_: impl Trait) {}
970        /// ```
971        ///
972        /// In this example, the generic parameter named `impl Trait` (and which
973        /// is bound by `Trait`) is synthetic, because it was not originally in
974        /// the Rust source text.
975        is_synthetic: bool,
976    },
977
978    /// Denotes a constant parameter.
979    Const {
980        /// The type of the constant as declared.
981        #[serde(rename = "type")]
982        type_: Type,
983        /// The stringified expression for the default value, if provided. It's not guaranteed that
984        /// it'll match the actual source code for the default value.
985        default: Option<String>,
986    },
987}
988
989/// One `where` clause.
990/// ```rust
991/// fn default<T>() -> T where T: Default { T::default() }
992/// //                         ^^^^^^^^^^
993/// ```
994#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
995#[serde(rename_all = "snake_case")]
996pub enum WherePredicate {
997    /// A type is expected to comply with a set of bounds
998    BoundPredicate {
999        /// The type that's being constrained.
1000        ///
1001        /// ```rust
1002        /// fn f<T>(x: T) where for<'a> &'a T: Iterator {}
1003        /// //                              ^
1004        /// ```
1005        #[serde(rename = "type")]
1006        type_: Type,
1007        /// The set of bounds that constrain the type.
1008        ///
1009        /// ```rust
1010        /// fn f<T>(x: T) where for<'a> &'a T: Iterator {}
1011        /// //                                 ^^^^^^^^
1012        /// ```
1013        bounds: Vec<GenericBound>,
1014        /// Used for Higher-Rank Trait Bounds (HRTBs)
1015        /// ```rust
1016        /// fn f<T>(x: T) where for<'a> &'a T: Iterator {}
1017        /// //                  ^^^^^^^
1018        /// ```
1019        generic_params: Vec<GenericParamDef>,
1020    },
1021
1022    /// A lifetime is expected to outlive other lifetimes.
1023    LifetimePredicate {
1024        /// The name of the lifetime.
1025        lifetime: String,
1026        /// The lifetimes that must be encompassed by the lifetime.
1027        outlives: Vec<String>,
1028    },
1029
1030    /// A type must exactly equal another type.
1031    EqPredicate {
1032        /// The left side of the equation.
1033        lhs: Type,
1034        /// The right side of the equation.
1035        rhs: Term,
1036    },
1037}
1038
1039/// Either a trait bound or a lifetime bound.
1040#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1041#[serde(rename_all = "snake_case")]
1042pub enum GenericBound {
1043    /// A trait bound.
1044    TraitBound {
1045        /// The full path to the trait.
1046        #[serde(rename = "trait")]
1047        trait_: Path,
1048        /// Used for Higher-Rank Trait Bounds (HRTBs)
1049        /// ```text
1050        /// where F: for<'a, 'b> Fn(&'a u8, &'b u8)
1051        ///          ^^^^^^^^^^^
1052        ///          |
1053        ///          this part
1054        /// ```
1055        generic_params: Vec<GenericParamDef>,
1056        /// The context for which a trait is supposed to be used, e.g. `const
1057        modifier: TraitBoundModifier,
1058    },
1059    /// A lifetime bound, e.g.
1060    /// ```rust
1061    /// fn f<'a, T>(x: &'a str, y: &T) where T: 'a {}
1062    /// //                                     ^^^
1063    /// ```
1064    Outlives(String),
1065    /// `use<'a, T>` precise-capturing bound syntax
1066    Use(Vec<PreciseCapturingArg>),
1067}
1068
1069/// A set of modifiers applied to a trait.
1070#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1071#[serde(rename_all = "snake_case")]
1072pub enum TraitBoundModifier {
1073    /// Marks the absence of a modifier.
1074    None,
1075    /// Indicates that the trait bound relaxes a trait bound applied to a parameter by default,
1076    /// e.g. `T: Sized?`, the `Sized` trait is required for all generic type parameters by default
1077    /// unless specified otherwise with this modifier.
1078    Maybe,
1079    /// Indicates that the trait bound must be applicable in both a run-time and a compile-time
1080    /// context.
1081    MaybeConst,
1082}
1083
1084/// One precise capturing argument. See [the rust reference](https://doc.rust-lang.org/reference/types/impl-trait.html#precise-capturing).
1085#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1086#[serde(rename_all = "snake_case")]
1087pub enum PreciseCapturingArg {
1088    /// A lifetime.
1089    /// ```rust
1090    /// pub fn hello<'a, T, const N: usize>() -> impl Sized + use<'a, T, N> {}
1091    /// //                                                        ^^
1092    Lifetime(String),
1093    /// A type or constant parameter.
1094    /// ```rust
1095    /// pub fn hello<'a, T, const N: usize>() -> impl Sized + use<'a, T, N> {}
1096    /// //                                                            ^  ^
1097    Param(String),
1098}
1099
1100/// Either a type or a constant, usually stored as the right-hand side of an equation in places like
1101/// [`AssocItemConstraint`]
1102#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1103#[serde(rename_all = "snake_case")]
1104pub enum Term {
1105    /// A type.
1106    ///
1107    /// ```rust
1108    /// fn f(x: impl IntoIterator<Item = u32>) {}
1109    /// //                               ^^^
1110    /// ```
1111    Type(Type),
1112    /// A constant.
1113    ///
1114    /// ```ignore (incomplete feature in the snippet)
1115    /// trait Foo {
1116    ///     const BAR: usize;
1117    /// }
1118    ///
1119    /// fn f(x: impl Foo<BAR = 42>) {}
1120    /// //                     ^^
1121    /// ```
1122    Constant(Constant),
1123}
1124
1125/// A type.
1126#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1127#[serde(rename_all = "snake_case")]
1128pub enum Type {
1129    /// Structs, enums, unions and type aliases, e.g. `std::option::Option<u32>`
1130    ResolvedPath(Path),
1131    /// Dynamic trait object type (`dyn Trait`).
1132    DynTrait(DynTrait),
1133    /// Parameterized types. The contained string is the name of the parameter.
1134    Generic(String),
1135    /// Built-in numeric types (e.g. `u32`, `f32`), `bool`, `char`.
1136    Primitive(String),
1137    /// A function pointer type, e.g. `fn(u32) -> u32`, `extern "C" fn() -> *const u8`
1138    FunctionPointer(Box<FunctionPointer>),
1139    /// A tuple type, e.g. `(String, u32, Box<usize>)`
1140    Tuple(Vec<Type>),
1141    /// An unsized slice type, e.g. `[u32]`.
1142    Slice(Box<Type>),
1143    /// An array type, e.g. `[u32; 15]`
1144    Array {
1145        /// The type of the contained element.
1146        #[serde(rename = "type")]
1147        type_: Box<Type>,
1148        /// The stringified expression that is the length of the array.
1149        ///
1150        /// Keep in mind that it's not guaranteed to match the actual source code of the expression.
1151        len: String,
1152    },
1153    /// A pattern type, e.g. `u32 is 1..`
1154    ///
1155    /// See [the tracking issue](https://github.com/rust-lang/rust/issues/123646)
1156    Pat {
1157        /// The base type, e.g. the `u32` in `u32 is 1..`
1158        #[serde(rename = "type")]
1159        type_: Box<Type>,
1160        #[doc(hidden)]
1161        __pat_unstable_do_not_use: String,
1162    },
1163    /// An opaque type that satisfies a set of bounds, `impl TraitA + TraitB + ...`
1164    ImplTrait(Vec<GenericBound>),
1165    /// A type that's left to be inferred, `_`
1166    Infer,
1167    /// A raw pointer type, e.g. `*mut u32`, `*const u8`, etc.
1168    RawPointer {
1169        /// This is `true` for `*mut _` and `false` for `*const _`.
1170        is_mutable: bool,
1171        /// The type of the pointee.
1172        #[serde(rename = "type")]
1173        type_: Box<Type>,
1174    },
1175    /// `&'a mut String`, `&str`, etc.
1176    BorrowedRef {
1177        /// The name of the lifetime of the reference, if provided.
1178        lifetime: Option<String>,
1179        /// This is `true` for `&mut i32` and `false` for `&i32`
1180        is_mutable: bool,
1181        /// The type of the pointee, e.g. the `i32` in `&'a mut i32`
1182        #[serde(rename = "type")]
1183        type_: Box<Type>,
1184    },
1185    /// Associated types like `<Type as Trait>::Name` and `T::Item` where
1186    /// `T: Iterator` or inherent associated types like `Struct::Name`.
1187    QualifiedPath {
1188        /// The name of the associated type in the parent type.
1189        ///
1190        /// ```ignore (incomplete expression)
1191        /// <core::array::IntoIter<u32, 42> as Iterator>::Item
1192        /// //                                            ^^^^
1193        /// ```
1194        name: String,
1195        /// The generic arguments provided to the associated type.
1196        ///
1197        /// ```ignore (incomplete expression)
1198        /// <core::slice::IterMut<'static, u32> as BetterIterator>::Item<'static>
1199        /// //                                                          ^^^^^^^^^
1200        /// ```
1201        args: Option<Box<GenericArgs>>,
1202        /// The type with which this type is associated.
1203        ///
1204        /// ```ignore (incomplete expression)
1205        /// <core::array::IntoIter<u32, 42> as Iterator>::Item
1206        /// // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1207        /// ```
1208        self_type: Box<Type>,
1209        /// `None` iff this is an *inherent* associated type.
1210        #[serde(rename = "trait")]
1211        trait_: Option<Path>,
1212    },
1213}
1214
1215/// A type that has a simple path to it. This is the kind of type of structs, unions, enums, etc.
1216#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1217pub struct Path {
1218    /// The path of the type.
1219    ///
1220    /// This will be the path that is *used* (not where it is defined), so
1221    /// multiple `Path`s may have different values for this field even if
1222    /// they all refer to the same item. e.g.
1223    ///
1224    /// ```rust
1225    /// pub type Vec1 = std::vec::Vec<i32>; // path: "std::vec::Vec"
1226    /// pub type Vec2 = Vec<i32>; // path: "Vec"
1227    /// pub type Vec3 = std::prelude::v1::Vec<i32>; // path: "std::prelude::v1::Vec"
1228    /// ```
1229    //
1230    // Example tested in ./tests/rustdoc-json/path_name.rs
1231    pub path: String,
1232    /// The ID of the type.
1233    pub id: Id,
1234    /// Generic arguments to the type.
1235    ///
1236    /// ```ignore (incomplete expression)
1237    /// std::borrow::Cow<'static, str>
1238    /// //              ^^^^^^^^^^^^^^
1239    /// ```
1240    pub args: Option<Box<GenericArgs>>,
1241}
1242
1243/// A type that is a function pointer.
1244#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1245pub struct FunctionPointer {
1246    /// The signature of the function.
1247    pub sig: FunctionSignature,
1248    /// Used for Higher-Rank Trait Bounds (HRTBs)
1249    ///
1250    /// ```ignore (incomplete expression)
1251    ///    for<'c> fn(val: &'c i32) -> i32
1252    /// // ^^^^^^^
1253    /// ```
1254    pub generic_params: Vec<GenericParamDef>,
1255    /// The core properties of the function, such as the ABI it conforms to, whether it's unsafe, etc.
1256    pub header: FunctionHeader,
1257}
1258
1259/// The signature of a function.
1260#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1261pub struct FunctionSignature {
1262    /// List of argument names and their type.
1263    ///
1264    /// Note that not all names will be valid identifiers, as some of
1265    /// them may be patterns.
1266    pub inputs: Vec<(String, Type)>,
1267    /// The output type, if specified.
1268    pub output: Option<Type>,
1269    /// Whether the function accepts an arbitrary amount of trailing arguments the C way.
1270    ///
1271    /// ```ignore (incomplete code)
1272    /// fn printf(fmt: &str, ...);
1273    /// ```
1274    pub is_c_variadic: bool,
1275}
1276
1277/// A `trait` declaration.
1278#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1279pub struct Trait {
1280    /// Whether the trait is marked `auto` and is thus implemented automatically
1281    /// for all applicable types.
1282    pub is_auto: bool,
1283    /// Whether the trait is marked as `unsafe`.
1284    pub is_unsafe: bool,
1285    /// Whether the trait is [dyn compatible](https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility)[^1].
1286    ///
1287    /// [^1]: Formerly known as "object safe".
1288    pub is_dyn_compatible: bool,
1289    /// Associated [`Item`]s that can/must be implemented by the `impl` blocks.
1290    pub items: Vec<Id>,
1291    /// Information about the type parameters and `where` clauses of the trait.
1292    pub generics: Generics,
1293    /// Constraints that must be met by the implementor of the trait.
1294    pub bounds: Vec<GenericBound>,
1295    /// The implementations of the trait.
1296    pub implementations: Vec<Id>,
1297}
1298
1299/// A trait alias declaration, e.g. `trait Int = Add + Sub + Mul + Div;`
1300///
1301/// See [the tracking issue](https://github.com/rust-lang/rust/issues/41517)
1302#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1303pub struct TraitAlias {
1304    /// Information about the type parameters and `where` clauses of the alias.
1305    pub generics: Generics,
1306    /// The bounds that are associated with the alias.
1307    pub params: Vec<GenericBound>,
1308}
1309
1310/// An `impl` block.
1311#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1312pub struct Impl {
1313    /// Whether this impl is for an unsafe trait.
1314    pub is_unsafe: bool,
1315    /// Information about the impl’s type parameters and `where` clauses.
1316    pub generics: Generics,
1317    /// The list of the names of all the trait methods that weren't mentioned in this impl but
1318    /// were provided by the trait itself.
1319    ///
1320    /// For example, for this impl of the [`PartialEq`] trait:
1321    /// ```rust
1322    /// struct Foo;
1323    ///
1324    /// impl PartialEq for Foo {
1325    ///     fn eq(&self, other: &Self) -> bool { todo!() }
1326    /// }
1327    /// ```
1328    /// This field will be `["ne"]`, as it has a default implementation defined for it.
1329    pub provided_trait_methods: Vec<String>,
1330    /// The trait being implemented or `None` if the impl is inherent, which means
1331    /// `impl Struct {}` as opposed to `impl Trait for Struct {}`.
1332    #[serde(rename = "trait")]
1333    pub trait_: Option<Path>,
1334    /// The type that the impl block is for.
1335    #[serde(rename = "for")]
1336    pub for_: Type,
1337    /// The list of associated items contained in this impl block.
1338    pub items: Vec<Id>,
1339    /// Whether this is a negative impl (e.g. `!Sized` or `!Send`).
1340    pub is_negative: bool,
1341    /// Whether this is an impl that’s implied by the compiler
1342    /// (for autotraits, e.g. `Send` or `Sync`).
1343    pub is_synthetic: bool,
1344    // FIXME: document this
1345    pub blanket_impl: Option<Type>,
1346}
1347
1348/// A `use` statement.
1349#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1350#[serde(rename_all = "snake_case")]
1351pub struct Use {
1352    /// The full path being imported.
1353    pub source: String,
1354    /// May be different from the last segment of `source` when renaming imports:
1355    /// `use source as name;`
1356    pub name: String,
1357    /// The ID of the item being imported. Will be `None` in case of re-exports of primitives:
1358    /// ```rust
1359    /// pub use i32 as my_i32;
1360    /// ```
1361    pub id: Option<Id>,
1362    /// Whether this statement is a wildcard `use`, e.g. `use source::*;`
1363    pub is_glob: bool,
1364}
1365
1366/// A procedural macro.
1367#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1368pub struct ProcMacro {
1369    /// How this macro is supposed to be called: `foo!()`, `#[foo]` or `#[derive(foo)]`
1370    pub kind: MacroKind,
1371    /// Helper attributes defined by a macro to be used inside it.
1372    ///
1373    /// Defined only for derive macros.
1374    ///
1375    /// E.g. the [`Default`] derive macro defines a `#[default]` helper attribute so that one can
1376    /// do:
1377    ///
1378    /// ```rust
1379    /// #[derive(Default)]
1380    /// enum Option<T> {
1381    ///     #[default]
1382    ///     None,
1383    ///     Some(T),
1384    /// }
1385    /// ```
1386    pub helpers: Vec<String>,
1387}
1388
1389/// The way a [`ProcMacro`] is declared to be used.
1390#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1391#[serde(rename_all = "snake_case")]
1392pub enum MacroKind {
1393    /// A bang macro `foo!()`.
1394    Bang,
1395    /// An attribute macro `#[foo]`.
1396    Attr,
1397    /// A derive macro `#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]`
1398    Derive,
1399}
1400
1401/// A type alias declaration, e.g. `type Pig = std::borrow::Cow<'static, str>;`
1402#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1403pub struct TypeAlias {
1404    /// The type referred to by this alias.
1405    #[serde(rename = "type")]
1406    pub type_: Type,
1407    /// Information about the type parameters and `where` clauses of the alias.
1408    pub generics: Generics,
1409}
1410
1411/// A `static` declaration.
1412#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1413pub struct Static {
1414    /// The type of the static.
1415    #[serde(rename = "type")]
1416    pub type_: Type,
1417    /// This is `true` for mutable statics, declared as `static mut X: T = f();`
1418    pub is_mutable: bool,
1419    /// The stringified expression for the initial value.
1420    ///
1421    /// It's not guaranteed that it'll match the actual source code for the initial value.
1422    pub expr: String,
1423
1424    /// Is the static `unsafe`?
1425    ///
1426    /// This is only true if it's in an `extern` block, and not explicitly marked
1427    /// as `safe`.
1428    ///
1429    /// ```rust
1430    /// unsafe extern {
1431    ///     static A: i32;      // unsafe
1432    ///     safe static B: i32; // safe
1433    /// }
1434    ///
1435    /// static C: i32 = 0;     // safe
1436    /// static mut D: i32 = 0; // safe
1437    /// ```
1438    pub is_unsafe: bool,
1439}
1440
1441/// A primitive type declaration. Declarations of this kind can only come from the core library.
1442#[derive(Clone, Debug, PartialEq, Eq, Hash, Serialize, Deserialize)]
1443pub struct Primitive {
1444    /// The name of the type.
1445    pub name: String,
1446    /// The implementations, inherent and of traits, on the primitive type.
1447    pub impls: Vec<Id>,
1448}
1449
1450#[cfg(test)]
1451mod tests;