1 //! A desugared representation of paths like `crate::foo` or `<Type as Trait>::bar`.
10 use crate::{body::LowerCtx, db::DefDatabase, intern::Interned, type_ref::LifetimeRef};
19 type_ref::{TypeBound, TypeRef},
23 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
29 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
32 /// `self::` is `Super(0)`
35 /// Absolute path (::foo)
37 /// `$crate` from macro expansion
41 #[derive(Debug, Clone, PartialEq, Eq)]
42 pub enum ImportAlias {
43 /// Unnamed alias, as in `use Foo as _;`
49 impl Display for ImportAlias {
50 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
52 ImportAlias::Underscore => f.write_str("_"),
53 ImportAlias::Alias(name) => f.write_str(&name.to_string()),
59 pub fn from_src(db: &dyn DefDatabase, path: ast::Path, hygiene: &Hygiene) -> Option<ModPath> {
60 let ctx = LowerCtx::with_hygiene(db, hygiene);
61 lower::lower_path(path, &ctx).map(|it| (*it.mod_path).clone())
64 pub fn from_segments(kind: PathKind, segments: impl IntoIterator<Item = Name>) -> ModPath {
65 let segments = segments.into_iter().collect::<Vec<_>>();
66 ModPath { kind, segments }
69 /// Creates a `ModPath` from a `PathKind`, with no extra path segments.
70 pub const fn from_kind(kind: PathKind) -> ModPath {
71 ModPath { kind, segments: Vec::new() }
74 /// Calls `cb` with all paths, represented by this use item.
75 pub(crate) fn expand_use_item(
77 item_src: InFile<ast::Use>,
79 mut cb: impl FnMut(ModPath, &ast::UseTree, /* is_glob */ bool, Option<ImportAlias>),
81 if let Some(tree) = item_src.value.use_tree() {
82 lower::lower_use_tree(db, None, tree, hygiene, &mut cb);
86 pub fn segments(&self) -> &[Name] {
90 pub fn push_segment(&mut self, segment: Name) {
91 self.segments.push(segment);
94 pub fn pop_segment(&mut self) -> Option<Name> {
98 /// Returns the number of segments in the path (counting special segments like `$crate` and
100 pub fn len(&self) -> usize {
103 PathKind::Plain => 0,
104 PathKind::Super(i) => i as usize,
105 PathKind::Crate => 1,
107 PathKind::DollarCrate(_) => 1,
111 pub fn is_ident(&self) -> bool {
112 self.as_ident().is_some()
115 pub fn is_self(&self) -> bool {
116 self.kind == PathKind::Super(0) && self.segments.is_empty()
119 /// If this path is a single identifier, like `foo`, return its name.
120 pub fn as_ident(&self) -> Option<&Name> {
121 if self.kind != PathKind::Plain {
125 match &*self.segments {
126 [name] => Some(name),
132 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
134 /// Type based path like `<T>::foo`.
135 /// Note that paths like `<Type as Trait>::foo` are desugard to `Trait::<Self=Type>::foo`.
136 type_anchor: Option<Interned<TypeRef>>,
137 mod_path: Interned<ModPath>,
138 /// Invariant: the same len as `self.mod_path.segments`
139 generic_args: Vec<Option<Arc<GenericArgs>>>,
142 /// Generic arguments to a path segment (e.g. the `i32` in `Option<i32>`). This
143 /// also includes bindings of associated types, like in `Iterator<Item = Foo>`.
144 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
145 pub struct GenericArgs {
146 pub args: Vec<GenericArg>,
147 /// This specifies whether the args contain a Self type as the first
148 /// element. This is the case for path segments like `<T as Trait>`, where
149 /// `T` is actually a type parameter for the path `Trait` specifying the
150 /// Self type. Otherwise, when we have a path `Trait<X, Y>`, the Self type
152 pub has_self_type: bool,
153 /// Associated type bindings like in `Iterator<Item = T>`.
154 pub bindings: Vec<AssociatedTypeBinding>,
157 /// An associated type binding like in `Iterator<Item = T>`.
158 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
159 pub struct AssociatedTypeBinding {
160 /// The name of the associated type.
162 /// The type bound to this associated type (in `Item = T`, this would be the
163 /// `T`). This can be `None` if there are bounds instead.
164 pub type_ref: Option<TypeRef>,
165 /// Bounds for the associated type, like in `Iterator<Item:
166 /// SomeOtherTrait>`. (This is the unstable `associated_type_bounds`
168 pub bounds: Vec<Interned<TypeBound>>,
171 /// A single generic argument.
172 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
173 pub enum GenericArg {
175 Lifetime(LifetimeRef),
179 /// Converts an `ast::Path` to `Path`. Works with use trees.
180 /// It correctly handles `$crate` based path from macro call.
181 pub fn from_src(path: ast::Path, ctx: &LowerCtx) -> Option<Path> {
182 lower::lower_path(path, ctx)
185 /// Converts a known mod path to `Path`.
186 pub(crate) fn from_known_path(
188 generic_args: Vec<Option<Arc<GenericArgs>>>,
190 Path { type_anchor: None, mod_path: Interned::new(path), generic_args }
193 pub fn kind(&self) -> &PathKind {
197 pub fn type_anchor(&self) -> Option<&TypeRef> {
198 self.type_anchor.as_deref()
201 pub fn segments(&self) -> PathSegments<'_> {
203 segments: self.mod_path.segments.as_slice(),
204 generic_args: self.generic_args.as_slice(),
208 pub fn mod_path(&self) -> &ModPath {
212 pub fn qualifier(&self) -> Option<Path> {
213 if self.mod_path.is_ident() {
217 type_anchor: self.type_anchor.clone(),
218 mod_path: Interned::new(ModPath::from_segments(
219 self.mod_path.kind.clone(),
220 self.mod_path.segments[..self.mod_path.segments.len() - 1].iter().cloned(),
222 generic_args: self.generic_args[..self.generic_args.len() - 1].to_vec(),
227 pub fn is_self_type(&self) -> bool {
228 self.type_anchor.is_none()
229 && self.generic_args == &[None]
230 && self.mod_path.as_ident() == Some(&name!(Self))
234 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
235 pub struct PathSegment<'a> {
237 pub args_and_bindings: Option<&'a GenericArgs>,
240 pub struct PathSegments<'a> {
241 segments: &'a [Name],
242 generic_args: &'a [Option<Arc<GenericArgs>>],
245 impl<'a> PathSegments<'a> {
246 pub const EMPTY: PathSegments<'static> = PathSegments { segments: &[], generic_args: &[] };
247 pub fn is_empty(&self) -> bool {
250 pub fn len(&self) -> usize {
253 pub fn first(&self) -> Option<PathSegment<'a>> {
256 pub fn last(&self) -> Option<PathSegment<'a>> {
257 self.get(self.len().checked_sub(1)?)
259 pub fn get(&self, idx: usize) -> Option<PathSegment<'a>> {
260 assert_eq!(self.segments.len(), self.generic_args.len());
261 let res = PathSegment {
262 name: self.segments.get(idx)?,
263 args_and_bindings: self.generic_args.get(idx).unwrap().as_ref().map(|it| &**it),
267 pub fn skip(&self, len: usize) -> PathSegments<'a> {
268 assert_eq!(self.segments.len(), self.generic_args.len());
269 PathSegments { segments: &self.segments[len..], generic_args: &self.generic_args[len..] }
271 pub fn take(&self, len: usize) -> PathSegments<'a> {
272 assert_eq!(self.segments.len(), self.generic_args.len());
273 PathSegments { segments: &self.segments[..len], generic_args: &self.generic_args[..len] }
275 pub fn iter(&self) -> impl Iterator<Item = PathSegment<'a>> {
276 self.segments.iter().zip(self.generic_args.iter()).map(|(name, args)| PathSegment {
278 args_and_bindings: args.as_ref().map(|it| &**it),
284 pub(crate) fn from_ast(lower_ctx: &LowerCtx, node: ast::GenericArgList) -> Option<GenericArgs> {
285 lower::lower_generic_args(lower_ctx, node)
288 pub(crate) fn empty() -> GenericArgs {
289 GenericArgs { args: Vec::new(), has_self_type: false, bindings: Vec::new() }
293 impl From<Name> for Path {
294 fn from(name: Name) -> Path {
297 mod_path: Interned::new(ModPath::from_segments(PathKind::Plain, iter::once(name))),
298 generic_args: vec![None],
303 impl From<Name> for Box<Path> {
304 fn from(name: Name) -> Box<Path> {
305 Box::new(Path::from(name))
309 impl From<Name> for ModPath {
310 fn from(name: Name) -> ModPath {
311 ModPath::from_segments(PathKind::Plain, iter::once(name))
315 impl Display for ModPath {
316 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
317 let mut first_segment = true;
318 let mut add_segment = |s| -> fmt::Result {
322 first_segment = false;
327 PathKind::Plain => {}
328 PathKind::Super(0) => add_segment("self")?,
329 PathKind::Super(n) => {
331 add_segment("super")?;
334 PathKind::Crate => add_segment("crate")?,
335 PathKind::Abs => add_segment("")?,
336 PathKind::DollarCrate(_) => add_segment("$crate")?,
338 for segment in &self.segments {
342 first_segment = false;
343 write!(f, "{}", segment)?;
349 pub use hir_expand::name as __name;
352 macro_rules! __known_path {
353 (core::iter::IntoIterator) => {};
354 (core::iter::Iterator) => {};
355 (core::result::Result) => {};
356 (core::option::Option) => {};
357 (core::ops::Range) => {};
358 (core::ops::RangeFrom) => {};
359 (core::ops::RangeFull) => {};
360 (core::ops::RangeTo) => {};
361 (core::ops::RangeToInclusive) => {};
362 (core::ops::RangeInclusive) => {};
363 (core::future::Future) => {};
364 (core::ops::Try) => {};
366 compile_error!("Please register your known path in the path module")
371 macro_rules! __path {
372 ($start:ident $(:: $seg:ident)*) => ({
373 $crate::__known_path!($start $(:: $seg)*);
374 $crate::path::ModPath::from_segments($crate::path::PathKind::Abs, vec![
375 $crate::path::__name![$start], $($crate::path::__name![$seg],)*
380 pub use crate::__path as path;