1 //! A desugared representation of paths like `crate::foo` or `<Type as Trait>::bar`.
9 use crate::{body::LowerCtx, db::DefDatabase, intern::Interned, type_ref::LifetimeRef};
17 use crate::type_ref::{TypeBound, TypeRef};
19 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
25 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
28 /// `self::` is `Super(0)`
31 /// Absolute path (::foo)
33 /// `$crate` from macro expansion
37 #[derive(Debug, Clone, PartialEq, Eq)]
38 pub enum ImportAlias {
39 /// Unnamed alias, as in `use Foo as _;`
45 impl Display for ImportAlias {
46 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
48 ImportAlias::Underscore => f.write_str("_"),
49 ImportAlias::Alias(name) => f.write_str(&name.to_smol_str()),
55 pub fn from_src(db: &dyn DefDatabase, path: ast::Path, hygiene: &Hygiene) -> Option<ModPath> {
56 lower::convert_path(db, None, path, hygiene)
59 pub fn from_segments(kind: PathKind, segments: impl IntoIterator<Item = Name>) -> ModPath {
60 let segments = segments.into_iter().collect::<Vec<_>>();
61 ModPath { kind, segments }
64 /// Creates a `ModPath` from a `PathKind`, with no extra path segments.
65 pub const fn from_kind(kind: PathKind) -> ModPath {
66 ModPath { kind, segments: Vec::new() }
69 pub fn segments(&self) -> &[Name] {
73 pub fn push_segment(&mut self, segment: Name) {
74 self.segments.push(segment);
77 pub fn pop_segment(&mut self) -> Option<Name> {
81 /// Returns the number of segments in the path (counting special segments like `$crate` and
83 pub fn len(&self) -> usize {
87 PathKind::Super(i) => i as usize,
90 PathKind::DollarCrate(_) => 1,
94 pub fn is_ident(&self) -> bool {
95 self.as_ident().is_some()
98 pub fn is_self(&self) -> bool {
99 self.kind == PathKind::Super(0) && self.segments.is_empty()
102 /// If this path is a single identifier, like `foo`, return its name.
103 pub fn as_ident(&self) -> Option<&Name> {
104 if self.kind != PathKind::Plain {
108 match &*self.segments {
109 [name] => Some(name),
115 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
117 /// Type based path like `<T>::foo`.
118 /// Note that paths like `<Type as Trait>::foo` are desugard to `Trait::<Self=Type>::foo`.
119 type_anchor: Option<Interned<TypeRef>>,
120 mod_path: Interned<ModPath>,
121 /// Invariant: the same len as `self.mod_path.segments`
122 generic_args: Vec<Option<Interned<GenericArgs>>>,
125 /// Generic arguments to a path segment (e.g. the `i32` in `Option<i32>`). This
126 /// also includes bindings of associated types, like in `Iterator<Item = Foo>`.
127 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
128 pub struct GenericArgs {
129 pub args: Vec<GenericArg>,
130 /// This specifies whether the args contain a Self type as the first
131 /// element. This is the case for path segments like `<T as Trait>`, where
132 /// `T` is actually a type parameter for the path `Trait` specifying the
133 /// Self type. Otherwise, when we have a path `Trait<X, Y>`, the Self type
135 pub has_self_type: bool,
136 /// Associated type bindings like in `Iterator<Item = T>`.
137 pub bindings: Vec<AssociatedTypeBinding>,
138 /// Whether these generic args were desugared from `Trait(Arg) -> Output`
139 /// parenthesis notation typically used for the `Fn` traits.
140 pub desugared_from_fn: bool,
143 /// An associated type binding like in `Iterator<Item = T>`.
144 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
145 pub struct AssociatedTypeBinding {
146 /// The name of the associated type.
148 /// The type bound to this associated type (in `Item = T`, this would be the
149 /// `T`). This can be `None` if there are bounds instead.
150 pub type_ref: Option<TypeRef>,
151 /// Bounds for the associated type, like in `Iterator<Item:
152 /// SomeOtherTrait>`. (This is the unstable `associated_type_bounds`
154 pub bounds: Vec<Interned<TypeBound>>,
157 /// A single generic argument.
158 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
159 pub enum GenericArg {
161 Lifetime(LifetimeRef),
165 /// Converts an `ast::Path` to `Path`. Works with use trees.
166 /// It correctly handles `$crate` based path from macro call.
167 pub fn from_src(path: ast::Path, ctx: &LowerCtx) -> Option<Path> {
168 lower::lower_path(path, ctx)
171 /// Converts a known mod path to `Path`.
172 pub fn from_known_path(
174 generic_args: Vec<Option<Interned<GenericArgs>>>,
176 Path { type_anchor: None, mod_path: Interned::new(path), generic_args }
179 pub fn kind(&self) -> &PathKind {
183 pub fn type_anchor(&self) -> Option<&TypeRef> {
184 self.type_anchor.as_deref()
187 pub fn segments(&self) -> PathSegments<'_> {
189 segments: self.mod_path.segments.as_slice(),
190 generic_args: self.generic_args.as_slice(),
194 pub fn mod_path(&self) -> &ModPath {
198 pub fn qualifier(&self) -> Option<Path> {
199 if self.mod_path.is_ident() {
203 type_anchor: self.type_anchor.clone(),
204 mod_path: Interned::new(ModPath::from_segments(
205 self.mod_path.kind.clone(),
206 self.mod_path.segments[..self.mod_path.segments.len() - 1].iter().cloned(),
208 generic_args: self.generic_args[..self.generic_args.len() - 1].to_vec(),
213 pub fn is_self_type(&self) -> bool {
214 self.type_anchor.is_none()
215 && self.generic_args == [None]
216 && self.mod_path.as_ident() == Some(&name!(Self))
220 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
221 pub struct PathSegment<'a> {
223 pub args_and_bindings: Option<&'a GenericArgs>,
226 pub struct PathSegments<'a> {
227 segments: &'a [Name],
228 generic_args: &'a [Option<Interned<GenericArgs>>],
231 impl<'a> PathSegments<'a> {
232 pub const EMPTY: PathSegments<'static> = PathSegments { segments: &[], generic_args: &[] };
233 pub fn is_empty(&self) -> bool {
236 pub fn len(&self) -> usize {
239 pub fn first(&self) -> Option<PathSegment<'a>> {
242 pub fn last(&self) -> Option<PathSegment<'a>> {
243 self.get(self.len().checked_sub(1)?)
245 pub fn get(&self, idx: usize) -> Option<PathSegment<'a>> {
246 assert_eq!(self.segments.len(), self.generic_args.len());
247 let res = PathSegment {
248 name: self.segments.get(idx)?,
249 args_and_bindings: self.generic_args.get(idx).unwrap().as_ref().map(|it| &**it),
253 pub fn skip(&self, len: usize) -> PathSegments<'a> {
254 assert_eq!(self.segments.len(), self.generic_args.len());
255 PathSegments { segments: &self.segments[len..], generic_args: &self.generic_args[len..] }
257 pub fn take(&self, len: usize) -> PathSegments<'a> {
258 assert_eq!(self.segments.len(), self.generic_args.len());
259 PathSegments { segments: &self.segments[..len], generic_args: &self.generic_args[..len] }
261 pub fn iter(&self) -> impl Iterator<Item = PathSegment<'a>> {
262 self.segments.iter().zip(self.generic_args.iter()).map(|(name, args)| PathSegment {
264 args_and_bindings: args.as_ref().map(|it| &**it),
270 pub(crate) fn from_ast(lower_ctx: &LowerCtx, node: ast::GenericArgList) -> Option<GenericArgs> {
271 lower::lower_generic_args(lower_ctx, node)
274 pub(crate) fn empty() -> GenericArgs {
277 has_self_type: false,
278 bindings: Vec::new(),
279 desugared_from_fn: false,
284 impl From<Name> for Path {
285 fn from(name: Name) -> Path {
288 mod_path: Interned::new(ModPath::from_segments(PathKind::Plain, iter::once(name))),
289 generic_args: vec![None],
294 impl From<Name> for Box<Path> {
295 fn from(name: Name) -> Box<Path> {
296 Box::new(Path::from(name))
300 impl From<Name> for ModPath {
301 fn from(name: Name) -> ModPath {
302 ModPath::from_segments(PathKind::Plain, iter::once(name))
306 impl Display for ModPath {
307 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
308 let mut first_segment = true;
309 let mut add_segment = |s| -> fmt::Result {
313 first_segment = false;
318 PathKind::Plain => {}
319 PathKind::Super(0) => add_segment("self")?,
320 PathKind::Super(n) => {
322 add_segment("super")?;
325 PathKind::Crate => add_segment("crate")?,
326 PathKind::Abs => add_segment("")?,
327 PathKind::DollarCrate(_) => add_segment("$crate")?,
329 for segment in &self.segments {
333 first_segment = false;
334 write!(f, "{}", segment)?;
340 pub use hir_expand::name as __name;
343 macro_rules! __known_path {
344 (core::iter::IntoIterator) => {};
345 (core::iter::Iterator) => {};
346 (core::result::Result) => {};
347 (core::option::Option) => {};
348 (core::ops::Range) => {};
349 (core::ops::RangeFrom) => {};
350 (core::ops::RangeFull) => {};
351 (core::ops::RangeTo) => {};
352 (core::ops::RangeToInclusive) => {};
353 (core::ops::RangeInclusive) => {};
354 (core::future::Future) => {};
355 (core::ops::Try) => {};
357 compile_error!("Please register your known path in the path module")
362 macro_rules! __path {
363 ($start:ident $(:: $seg:ident)*) => ({
364 $crate::__known_path!($start $(:: $seg)*);
365 $crate::path::ModPath::from_segments($crate::path::PathKind::Abs, vec![
366 $crate::path::__name![$start], $($crate::path::__name![$seg],)*
371 pub use crate::__path as path;