rust/crates/hir_def/src/path.rs

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//! A desugared representation of paths like `crate::foo` or `<Type as Trait>::bar`.
mod lower;
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use std::{
fmt::{self, Display},
iter,
sync::Arc,
};
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use crate::{body::LowerCtx, db::DefDatabase, intern::Interned, type_ref::LifetimeRef};
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use base_db::CrateId;
use hir_expand::{
hygiene::Hygiene,
name::{name, Name},
};
use syntax::ast;
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use crate::{
type_ref::{TypeBound, TypeRef},
InFile,
};
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ModPath {
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pub kind: PathKind,
segments: Vec<Name>,
}
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
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pub enum PathKind {
Plain,
/// `self::` is `Super(0)`
Super(u8),
Crate,
/// Absolute path (::foo)
Abs,
/// `$crate` from macro expansion
DollarCrate(CrateId),
}
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#[derive(Debug, Clone, PartialEq, Eq)]
pub enum ImportAlias {
/// Unnamed alias, as in `use Foo as _;`
Underscore,
/// Named alias
Alias(Name),
}
impl ModPath {
pub fn from_src(db: &dyn DefDatabase, path: ast::Path, hygiene: &Hygiene) -> Option<ModPath> {
let ctx = LowerCtx::with_hygiene(db, hygiene);
lower::lower_path(db, path, &ctx).map(|it| (*it.mod_path).clone())
}
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pub fn from_segments(kind: PathKind, segments: impl IntoIterator<Item = Name>) -> ModPath {
let segments = segments.into_iter().collect::<Vec<_>>();
ModPath { kind, segments }
}
/// Creates a `ModPath` from a `PathKind`, with no extra path segments.
pub const fn from_kind(kind: PathKind) -> ModPath {
ModPath { kind, segments: Vec::new() }
}
/// Calls `cb` with all paths, represented by this use item.
pub(crate) fn expand_use_item(
db: &dyn DefDatabase,
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item_src: InFile<ast::Use>,
hygiene: &Hygiene,
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mut cb: impl FnMut(ModPath, &ast::UseTree, /* is_glob */ bool, Option<ImportAlias>),
) {
if let Some(tree) = item_src.value.use_tree() {
lower::lower_use_tree(db, None, tree, hygiene, &mut cb);
}
}
pub fn segments(&self) -> &[Name] {
&self.segments
}
pub fn push_segment(&mut self, segment: Name) {
self.segments.push(segment);
}
pub fn pop_segment(&mut self) -> Option<Name> {
self.segments.pop()
}
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/// Returns the number of segments in the path (counting special segments like `$crate` and
/// `super`).
pub fn len(&self) -> usize {
self.segments.len()
+ match self.kind {
PathKind::Plain => 0,
PathKind::Super(i) => i as usize,
PathKind::Crate => 1,
PathKind::Abs => 0,
PathKind::DollarCrate(_) => 1,
}
}
pub fn is_ident(&self) -> bool {
self.as_ident().is_some()
}
pub fn is_self(&self) -> bool {
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self.kind == PathKind::Super(0) && self.segments.is_empty()
}
/// If this path is a single identifier, like `foo`, return its name.
pub fn as_ident(&self) -> Option<&Name> {
if self.kind != PathKind::Plain {
return None;
}
match &*self.segments {
[name] => Some(name),
_ => None,
}
}
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}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct Path {
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/// Type based path like `<T>::foo`.
/// Note that paths like `<Type as Trait>::foo` are desugard to `Trait::<Self=Type>::foo`.
type_anchor: Option<Interned<TypeRef>>,
mod_path: Interned<ModPath>,
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/// Invariant: the same len as `self.mod_path.segments`
generic_args: Vec<Option<Arc<GenericArgs>>>,
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}
/// Generic arguments to a path segment (e.g. the `i32` in `Option<i32>`). This
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/// also includes bindings of associated types, like in `Iterator<Item = Foo>`.
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct GenericArgs {
pub args: Vec<GenericArg>,
/// This specifies whether the args contain a Self type as the first
/// element. This is the case for path segments like `<T as Trait>`, where
/// `T` is actually a type parameter for the path `Trait` specifying the
/// Self type. Otherwise, when we have a path `Trait<X, Y>`, the Self type
/// is left out.
pub has_self_type: bool,
/// Associated type bindings like in `Iterator<Item = T>`.
pub bindings: Vec<AssociatedTypeBinding>,
}
/// An associated type binding like in `Iterator<Item = T>`.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct AssociatedTypeBinding {
/// The name of the associated type.
pub name: Name,
/// The type bound to this associated type (in `Item = T`, this would be the
/// `T`). This can be `None` if there are bounds instead.
pub type_ref: Option<TypeRef>,
/// Bounds for the associated type, like in `Iterator<Item:
/// SomeOtherTrait>`. (This is the unstable `associated_type_bounds`
/// feature.)
pub bounds: Vec<TypeBound>,
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}
/// A single generic argument.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub enum GenericArg {
Type(TypeRef),
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Lifetime(LifetimeRef),
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}
impl Path {
/// Converts an `ast::Path` to `Path`. Works with use trees.
/// It correctly handles `$crate` based path from macro call.
pub fn from_src(db: &dyn DefDatabase, path: ast::Path, ctx: &LowerCtx) -> Option<Path> {
lower::lower_path(db, path, ctx)
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}
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/// Converts a known mod path to `Path`.
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pub(crate) fn from_known_path(
path: ModPath,
generic_args: Vec<Option<Arc<GenericArgs>>>,
) -> Path {
Path { type_anchor: None, mod_path: Interned::new(path), generic_args }
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}
pub fn kind(&self) -> &PathKind {
&self.mod_path.kind
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}
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pub fn type_anchor(&self) -> Option<&TypeRef> {
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self.type_anchor.as_deref()
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}
pub fn segments(&self) -> PathSegments<'_> {
PathSegments {
segments: self.mod_path.segments.as_slice(),
generic_args: self.generic_args.as_slice(),
}
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}
pub fn mod_path(&self) -> &ModPath {
&self.mod_path
}
pub fn qualifier(&self) -> Option<Path> {
if self.mod_path.is_ident() {
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return None;
}
let res = Path {
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type_anchor: self.type_anchor.clone(),
mod_path: Interned::new(ModPath::from_segments(
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self.mod_path.kind.clone(),
self.mod_path.segments[..self.mod_path.segments.len() - 1].iter().cloned(),
)),
generic_args: self.generic_args[..self.generic_args.len() - 1].to_vec(),
};
Some(res)
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}
pub fn is_self_type(&self) -> bool {
self.type_anchor.is_none()
&& self.generic_args == &[None]
&& self.mod_path.as_ident() == Some(&name!(Self))
}
}
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct PathSegment<'a> {
pub name: &'a Name,
pub args_and_bindings: Option<&'a GenericArgs>,
}
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pub struct PathSegments<'a> {
segments: &'a [Name],
generic_args: &'a [Option<Arc<GenericArgs>>],
}
impl<'a> PathSegments<'a> {
pub const EMPTY: PathSegments<'static> = PathSegments { segments: &[], generic_args: &[] };
pub fn is_empty(&self) -> bool {
self.len() == 0
}
pub fn len(&self) -> usize {
self.segments.len()
}
pub fn first(&self) -> Option<PathSegment<'a>> {
self.get(0)
}
pub fn last(&self) -> Option<PathSegment<'a>> {
self.get(self.len().checked_sub(1)?)
}
pub fn get(&self, idx: usize) -> Option<PathSegment<'a>> {
assert_eq!(self.segments.len(), self.generic_args.len());
let res = PathSegment {
name: self.segments.get(idx)?,
args_and_bindings: self.generic_args.get(idx).unwrap().as_ref().map(|it| &**it),
};
Some(res)
}
pub fn skip(&self, len: usize) -> PathSegments<'a> {
assert_eq!(self.segments.len(), self.generic_args.len());
PathSegments { segments: &self.segments[len..], generic_args: &self.generic_args[len..] }
}
pub fn take(&self, len: usize) -> PathSegments<'a> {
assert_eq!(self.segments.len(), self.generic_args.len());
PathSegments { segments: &self.segments[..len], generic_args: &self.generic_args[..len] }
}
pub fn iter(&self) -> impl Iterator<Item = PathSegment<'a>> {
self.segments.iter().zip(self.generic_args.iter()).map(|(name, args)| PathSegment {
name,
args_and_bindings: args.as_ref().map(|it| &**it),
})
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}
}
impl GenericArgs {
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pub(crate) fn from_ast(lower_ctx: &LowerCtx, node: ast::GenericArgList) -> Option<GenericArgs> {
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lower::lower_generic_args(lower_ctx, node)
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}
pub(crate) fn empty() -> GenericArgs {
GenericArgs { args: Vec::new(), has_self_type: false, bindings: Vec::new() }
}
}
impl From<Name> for Path {
fn from(name: Name) -> Path {
Path {
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type_anchor: None,
mod_path: Interned::new(ModPath::from_segments(PathKind::Plain, iter::once(name))),
generic_args: vec![None],
}
}
}
impl From<Name> for Box<Path> {
fn from(name: Name) -> Box<Path> {
Box::new(Path::from(name))
}
}
impl From<Name> for ModPath {
fn from(name: Name) -> ModPath {
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ModPath::from_segments(PathKind::Plain, iter::once(name))
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}
}
impl Display for ModPath {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut first_segment = true;
let mut add_segment = |s| -> fmt::Result {
if !first_segment {
f.write_str("::")?;
}
first_segment = false;
f.write_str(s)?;
Ok(())
};
match self.kind {
PathKind::Plain => {}
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PathKind::Super(0) => add_segment("self")?,
PathKind::Super(n) => {
for _ in 0..n {
add_segment("super")?;
}
}
PathKind::Crate => add_segment("crate")?,
PathKind::Abs => add_segment("")?,
PathKind::DollarCrate(_) => add_segment("$crate")?,
}
for segment in &self.segments {
if !first_segment {
f.write_str("::")?;
}
first_segment = false;
write!(f, "{}", segment)?;
}
Ok(())
}
}
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pub use hir_expand::name as __name;
#[macro_export]
macro_rules! __known_path {
(core::iter::IntoIterator) => {};
(core::iter::Iterator) => {};
(core::result::Result) => {};
(core::option::Option) => {};
(core::ops::Range) => {};
(core::ops::RangeFrom) => {};
(core::ops::RangeFull) => {};
(core::ops::RangeTo) => {};
(core::ops::RangeToInclusive) => {};
(core::ops::RangeInclusive) => {};
(core::future::Future) => {};
(core::ops::Try) => {};
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($path:path) => {
compile_error!("Please register your known path in the path module")
};
}
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#[macro_export]
macro_rules! __path {
($start:ident $(:: $seg:ident)*) => ({
$crate::__known_path!($start $(:: $seg)*);
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$crate::path::ModPath::from_segments($crate::path::PathKind::Abs, vec![
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$crate::path::__name![$start], $($crate::path::__name![$seg],)*
])
});
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}
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pub use crate::__path as path;