Google Git
Sign in
android / toolchain / rustc / 32f7835b4f844d645621e83c89a3178ef87b0d69 / . / src / librustdoc / passes / collect_intra_doc_links.rs
blob: aeaceeefc08a1b7f33e00e72ba21502d78f25856 [file] [log] [blame]
//! This module implements [RFC 1946]: Intra-rustdoc-links
//!
//! [RFC 1946]: https://github.com/rust-lang/rfcs/blob/master/text/1946-intra-rustdoc-links.md
use rustc_ast as ast;
use rustc_data_structures::{fx::FxHashMap, stable_set::FxHashSet};
use rustc_errors::{Applicability, DiagnosticBuilder};
use rustc_expand::base::SyntaxExtensionKind;
use rustc_hir as hir;
use rustc_hir::def::{
DefKind,
Namespace::{self, *},
PerNS,
};
use rustc_hir::def_id::{CrateNum, DefId};
use rustc_middle::ty::TyCtxt;
use rustc_middle::{bug, ty};
use rustc_resolve::ParentScope;
use rustc_session::lint::Lint;
use rustc_span::hygiene::{MacroKind, SyntaxContext};
use rustc_span::symbol::{sym, Ident, Symbol};
use rustc_span::DUMMY_SP;
use smallvec::{smallvec, SmallVec};
use pulldown_cmark::LinkType;
use std::borrow::Cow;
use std::cell::Cell;
use std::convert::{TryFrom, TryInto};
use std::mem;
use std::ops::Range;
use crate::clean::{self, utils::find_nearest_parent_module, Crate, Item, ItemLink, PrimitiveType};
use crate::core::DocContext;
use crate::fold::DocFolder;
use crate::html::markdown::{markdown_links, MarkdownLink};
use crate::lint::{BROKEN_INTRA_DOC_LINKS, PRIVATE_INTRA_DOC_LINKS};
use crate::passes::Pass;
mod early;
crate use early::IntraLinkCrateLoader;
crate const COLLECT_INTRA_DOC_LINKS: Pass = Pass {
name: "collect-intra-doc-links",
run: collect_intra_doc_links,
description: "resolves intra-doc links",
};
fn collect_intra_doc_links(krate: Crate, cx: &mut DocContext<'_>) -> Crate {
LinkCollector {
cx,
mod_ids: Vec::new(),
kind_side_channel: Cell::new(None),
visited_links: FxHashMap::default(),
}
.fold_crate(krate)
}
/// Top-level errors emitted by this pass.
enum ErrorKind<'a> {
Resolve(Box<ResolutionFailure<'a>>),
AnchorFailure(AnchorFailure),
}
impl<'a> From<ResolutionFailure<'a>> for ErrorKind<'a> {
fn from(err: ResolutionFailure<'a>) -> Self {
ErrorKind::Resolve(box err)
}
}
#[derive(Copy, Clone, Debug, Hash)]
enum Res {
Def(DefKind, DefId),
Primitive(PrimitiveType),
}
type ResolveRes = rustc_hir::def::Res<rustc_ast::NodeId>;
impl Res {
fn descr(self) -> &'static str {
match self {
Res::Def(kind, id) => ResolveRes::Def(kind, id).descr(),
Res::Primitive(_) => "builtin type",
}
}
fn article(self) -> &'static str {
match self {
Res::Def(kind, id) => ResolveRes::Def(kind, id).article(),
Res::Primitive(_) => "a",
}
}
fn name(self, tcx: TyCtxt<'_>) -> String {
match self {
Res::Def(_, id) => tcx.item_name(id).to_string(),
Res::Primitive(prim) => prim.as_str().to_string(),
}
}
fn def_id(self) -> DefId {
self.opt_def_id().expect("called def_id() on a primitive")
}
fn opt_def_id(self) -> Option<DefId> {
match self {
Res::Def(_, id) => Some(id),
Res::Primitive(_) => None,
}
}
fn as_hir_res(self) -> Option<rustc_hir::def::Res> {
match self {
Res::Def(kind, id) => Some(rustc_hir::def::Res::Def(kind, id)),
// FIXME: maybe this should handle the subset of PrimitiveType that fits into hir::PrimTy?
Res::Primitive(_) => None,
}
}
}
impl TryFrom<ResolveRes> for Res {
type Error = ();
fn try_from(res: ResolveRes) -> Result<Self, ()> {
use rustc_hir::def::Res::*;
match res {
Def(kind, id) => Ok(Res::Def(kind, id)),
PrimTy(prim) => Ok(Res::Primitive(PrimitiveType::from_hir(prim))),
// e.g. `#[derive]`
NonMacroAttr(..) | Err => Result::Err(()),
other => bug!("unrecognized res {:?}", other),
}
}
}
/// A link failed to resolve.
#[derive(Debug)]
enum ResolutionFailure<'a> {
/// This resolved, but with the wrong namespace.
WrongNamespace {
/// What the link resolved to.
res: Res,
/// The expected namespace for the resolution, determined from the link's disambiguator.
///
/// E.g., for `[fn@Result]` this is [`Namespace::ValueNS`],
/// even though `Result`'s actual namespace is [`Namespace::TypeNS`].
expected_ns: Namespace,
},
/// The link failed to resolve. [`resolution_failure`] should look to see if there's
/// a more helpful error that can be given.
NotResolved {
/// The scope the link was resolved in.
module_id: DefId,
/// If part of the link resolved, this has the `Res`.
///
/// In `[std::io::Error::x]`, `std::io::Error` would be a partial resolution.
partial_res: Option<Res>,
/// The remaining unresolved path segments.
///
/// In `[std::io::Error::x]`, `x` would be unresolved.
unresolved: Cow<'a, str>,
},
/// This happens when rustdoc can't determine the parent scope for an item.
/// It is always a bug in rustdoc.
NoParentItem,
/// This link has malformed generic parameters; e.g., the angle brackets are unbalanced.
MalformedGenerics(MalformedGenerics),
/// Used to communicate that this should be ignored, but shouldn't be reported to the user.
///
/// This happens when there is no disambiguator and one of the namespaces
/// failed to resolve.
Dummy,
}
#[derive(Debug)]
enum MalformedGenerics {
/// This link has unbalanced angle brackets.
///
/// For example, `Vec<T` should trigger this, as should `Vec<T>>`.
UnbalancedAngleBrackets,
/// The generics are not attached to a type.
///
/// For example, `<T>` should trigger this.
///
/// This is detected by checking if the path is empty after the generics are stripped.
MissingType,
/// The link uses fully-qualified syntax, which is currently unsupported.
///
/// For example, `<Vec as IntoIterator>::into_iter` should trigger this.
///
/// This is detected by checking if ` as ` (the keyword `as` with spaces around it) is inside
/// angle brackets.
HasFullyQualifiedSyntax,
/// The link has an invalid path separator.
///
/// For example, `Vec:<T>:new()` should trigger this. Note that `Vec:new()` will **not**
/// trigger this because it has no generics and thus [`strip_generics_from_path`] will not be
/// called.
///
/// Note that this will also **not** be triggered if the invalid path separator is inside angle
/// brackets because rustdoc mostly ignores what's inside angle brackets (except for
/// [`HasFullyQualifiedSyntax`](MalformedGenerics::HasFullyQualifiedSyntax)).
///
/// This is detected by checking if there is a colon followed by a non-colon in the link.
InvalidPathSeparator,
/// The link has too many angle brackets.
///
/// For example, `Vec<<T>>` should trigger this.
TooManyAngleBrackets,
/// The link has empty angle brackets.
///
/// For example, `Vec<>` should trigger this.
EmptyAngleBrackets,
}
impl ResolutionFailure<'a> {
/// This resolved fully (not just partially) but is erroneous for some other reason
///
/// Returns the full resolution of the link, if present.
fn full_res(&self) -> Option<Res> {
match self {
Self::WrongNamespace { res, expected_ns: _ } => Some(*res),
_ => None,
}
}
}
enum AnchorFailure {
/// User error: `[std#x#y]` is not valid
MultipleAnchors,
/// The anchor provided by the user conflicts with Rustdoc's generated anchor.
///
/// This is an unfortunate state of affairs. Not every item that can be
/// linked to has its own page; sometimes it is a subheading within a page,
/// like for associated items. In those cases, rustdoc uses an anchor to
/// link to the subheading. Since you can't have two anchors for the same
/// link, Rustdoc disallows having a user-specified anchor.
///
/// Most of the time this is fine, because you can just link to the page of
/// the item if you want to provide your own anchor. For primitives, though,
/// rustdoc uses the anchor as a side channel to know which page to link to;
/// it doesn't show up in the generated link. Ideally, rustdoc would remove
/// this limitation, allowing you to link to subheaders on primitives.
RustdocAnchorConflict(Res),
}
#[derive(Clone, Debug, Hash, PartialEq, Eq)]
struct ResolutionInfo {
module_id: DefId,
dis: Option<Disambiguator>,
path_str: String,
extra_fragment: Option<String>,
}
#[derive(Clone)]
struct DiagnosticInfo<'a> {
item: &'a Item,
dox: &'a str,
ori_link: &'a str,
link_range: Range<usize>,
}
#[derive(Clone, Debug, Hash)]
struct CachedLink {
pub res: (Res, Option<String>),
pub side_channel: Option<(DefKind, DefId)>,
}
struct LinkCollector<'a, 'tcx> {
cx: &'a mut DocContext<'tcx>,
/// A stack of modules used to decide what scope to resolve in.
///
/// The last module will be used if the parent scope of the current item is
/// unknown.
mod_ids: Vec<DefId>,
/// This is used to store the kind of associated items,
/// because `clean` and the disambiguator code expect them to be different.
/// See the code for associated items on inherent impls for details.
kind_side_channel: Cell<Option<(DefKind, DefId)>>,
/// Cache the resolved links so we can avoid resolving (and emitting errors for) the same link.
/// The link will be `None` if it could not be resolved (i.e. the error was cached).
visited_links: FxHashMap<ResolutionInfo, Option<CachedLink>>,
}
impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
/// Given a full link, parse it as an [enum struct variant].
///
/// In particular, this will return an error whenever there aren't three
/// full path segments left in the link.
///
/// [enum struct variant]: hir::VariantData::Struct
fn variant_field(
&self,
path_str: &'path str,
module_id: DefId,
) -> Result<(Res, Option<String>), ErrorKind<'path>> {
let tcx = self.cx.tcx;
let no_res = || ResolutionFailure::NotResolved {
module_id,
partial_res: None,
unresolved: path_str.into(),
};
debug!("looking for enum variant {}", path_str);
let mut split = path_str.rsplitn(3, "::");
let (variant_field_str, variant_field_name) = split
.next()
.map(|f| (f, Symbol::intern(f)))
.expect("fold_item should ensure link is non-empty");
let (variant_str, variant_name) =
// we're not sure this is a variant at all, so use the full string
// If there's no second component, the link looks like `[path]`.
// So there's no partial res and we should say the whole link failed to resolve.
split.next().map(|f| (f, Symbol::intern(f))).ok_or_else(no_res)?;
let path = split
.next()
.map(|f| f.to_owned())
// If there's no third component, we saw `[a::b]` before and it failed to resolve.
// So there's no partial res.
.ok_or_else(no_res)?;
let ty_res = self
.cx
.enter_resolver(|resolver| {
resolver.resolve_str_path_error(DUMMY_SP, &path, TypeNS, module_id)
})
.and_then(|(_, res)| res.try_into())
.map_err(|()| no_res())?;
match ty_res {
Res::Def(DefKind::Enum, did) => {
if tcx
.inherent_impls(did)
.iter()
.flat_map(|imp| tcx.associated_items(*imp).in_definition_order())
.any(|item| item.ident.name == variant_name)
{
// This is just to let `fold_item` know that this shouldn't be considered;
// it's a bug for the error to make it to the user
return Err(ResolutionFailure::Dummy.into());
}
match tcx.type_of(did).kind() {
ty::Adt(def, _) if def.is_enum() => {
if def.all_fields().any(|item| item.ident.name == variant_field_name) {
Ok((
ty_res,
Some(format!(
"variant.{}.field.{}",
variant_str, variant_field_name
)),
))
} else {
Err(ResolutionFailure::NotResolved {
module_id,
partial_res: Some(Res::Def(DefKind::Enum, def.did)),
unresolved: variant_field_str.into(),
}
.into())
}
}
_ => unreachable!(),
}
}
_ => Err(ResolutionFailure::NotResolved {
module_id,
partial_res: Some(ty_res),
unresolved: variant_str.into(),
}
.into()),
}
}
/// Given a primitive type, try to resolve an associated item.
fn resolve_primitive_associated_item(
&self,
prim_ty: PrimitiveType,
ns: Namespace,
item_name: Symbol,
) -> Option<(Res, String, Option<(DefKind, DefId)>)> {
let tcx = self.cx.tcx;
prim_ty.impls(tcx).into_iter().find_map(|&impl_| {
tcx.associated_items(impl_)
.find_by_name_and_namespace(tcx, Ident::with_dummy_span(item_name), ns, impl_)
.map(|item| {
let kind = item.kind;
let out = match kind {
ty::AssocKind::Fn => "method",
ty::AssocKind::Const => "associatedconstant",
ty::AssocKind::Type => "associatedtype",
};
let fragment = format!("{}#{}.{}", prim_ty.as_str(), out, item_name);
(Res::Primitive(prim_ty), fragment, Some((kind.as_def_kind(), item.def_id)))
})
})
}
/// Resolves a string as a macro.
///
/// FIXME(jynelson): Can this be unified with `resolve()`?
fn resolve_macro(
&self,
path_str: &'a str,
module_id: DefId,
) -> Result<Res, ResolutionFailure<'a>> {
let path = ast::Path::from_ident(Ident::from_str(path_str));
self.cx.enter_resolver(|resolver| {
// FIXME(jynelson): does this really need 3 separate lookups?
if let Ok((Some(ext), res)) = resolver.resolve_macro_path(
&path,
None,
&ParentScope::module(resolver.graph_root(), resolver),
false,
false,
) {
if let SyntaxExtensionKind::LegacyBang { .. } = ext.kind {
return Ok(res.try_into().unwrap());
}
}
if let Some(&res) = resolver.all_macros().get(&Symbol::intern(path_str)) {
return Ok(res.try_into().unwrap());
}
debug!("resolving {} as a macro in the module {:?}", path_str, module_id);
if let Ok((_, res)) =
resolver.resolve_str_path_error(DUMMY_SP, path_str, MacroNS, module_id)
{
// don't resolve builtins like `#[derive]`
if let Ok(res) = res.try_into() {
return Ok(res);
}
}
Err(ResolutionFailure::NotResolved {
module_id,
partial_res: None,
unresolved: path_str.into(),
})
})
}
/// Convenience wrapper around `resolve_str_path_error`.
///
/// This also handles resolving `true` and `false` as booleans.
/// NOTE: `resolve_str_path_error` knows only about paths, not about types.
/// Associated items will never be resolved by this function.
fn resolve_path(&self, path_str: &str, ns: Namespace, module_id: DefId) -> Option<Res> {
let result = self.cx.enter_resolver(|resolver| {
resolver
.resolve_str_path_error(DUMMY_SP, &path_str, ns, module_id)
.and_then(|(_, res)| res.try_into())
});
debug!("{} resolved to {:?} in namespace {:?}", path_str, result, ns);
match result {
// resolver doesn't know about true, false, and types that aren't paths (e.g. `()`)
// manually as bool
Err(()) => resolve_primitive(path_str, ns),
Ok(res) => Some(res),
}
}
/// Resolves a string as a path within a particular namespace. Returns an
/// optional URL fragment in the case of variants and methods.
fn resolve<'path>(
&mut self,
path_str: &'path str,
ns: Namespace,
module_id: DefId,
extra_fragment: &Option<String>,
) -> Result<(Res, Option<String>), ErrorKind<'path>> {
if let Some(res) = self.resolve_path(path_str, ns, module_id) {
match res {
// FIXME(#76467): make this fallthrough to lookup the associated
// item a separate function.
Res::Def(DefKind::AssocFn | DefKind::AssocConst, _) => assert_eq!(ns, ValueNS),
Res::Def(DefKind::AssocTy, _) => assert_eq!(ns, TypeNS),
Res::Def(DefKind::Variant, _) => {
return handle_variant(self.cx, res, extra_fragment);
}
// Not a trait item; just return what we found.
Res::Primitive(ty) => {
if extra_fragment.is_some() {
return Err(ErrorKind::AnchorFailure(
AnchorFailure::RustdocAnchorConflict(res),
));
}
return Ok((res, Some(ty.as_str().to_owned())));
}
_ => return Ok((res, extra_fragment.clone())),
}
}
// Try looking for methods and associated items.
let mut split = path_str.rsplitn(2, "::");
// NB: `split`'s first element is always defined, even if the delimiter was not present.
// NB: `item_str` could be empty when resolving in the root namespace (e.g. `::std`).
let item_str = split.next().unwrap();
let item_name = Symbol::intern(item_str);
let path_root = split
.next()
.map(|f| f.to_owned())
// If there's no `::`, it's not an associated item.
// So we can be sure that `rustc_resolve` was accurate when it said it wasn't resolved.
.ok_or_else(|| {
debug!("found no `::`, assumming {} was correctly not in scope", item_name);
ResolutionFailure::NotResolved {
module_id,
partial_res: None,
unresolved: item_str.into(),
}
})?;
// FIXME(#83862): this arbitrarily gives precedence to primitives over modules to support
// links to primitives when `#[doc(primitive)]` is present. It should give an ambiguity
// error instead and special case *only* modules with `#[doc(primitive)]`, not all
// primitives.
resolve_primitive(&path_root, TypeNS)
.or_else(|| self.resolve_path(&path_root, TypeNS, module_id))
.and_then(|ty_res| {
let (res, fragment, side_channel) =
self.resolve_associated_item(ty_res, item_name, ns, module_id)?;
let result = if extra_fragment.is_some() {
let diag_res = side_channel.map_or(res, |(k, r)| Res::Def(k, r));
Err(ErrorKind::AnchorFailure(AnchorFailure::RustdocAnchorConflict(diag_res)))
} else {
// HACK(jynelson): `clean` expects the type, not the associated item
// but the disambiguator logic expects the associated item.
// Store the kind in a side channel so that only the disambiguator logic looks at it.
if let Some((kind, id)) = side_channel {
self.kind_side_channel.set(Some((kind, id)));
}
Ok((res, Some(fragment)))
};
Some(result)
})
.unwrap_or_else(|| {
if ns == Namespace::ValueNS {
self.variant_field(path_str, module_id)
} else {
Err(ResolutionFailure::NotResolved {
module_id,
partial_res: None,
unresolved: path_root.into(),
}
.into())
}
})
}
/// Returns:
/// - None if no associated item was found
/// - Some((_, _, Some(_))) if an item was found and should go through a side channel
/// - Some((_, _, None)) otherwise
fn resolve_associated_item(
&mut self,
root_res: Res,
item_name: Symbol,
ns: Namespace,
module_id: DefId,
) -> Option<(Res, String, Option<(DefKind, DefId)>)> {
let tcx = self.cx.tcx;
match root_res {
Res::Primitive(prim) => self.resolve_primitive_associated_item(prim, ns, item_name),
Res::Def(
DefKind::Struct
| DefKind::Union
| DefKind::Enum
| DefKind::TyAlias
| DefKind::ForeignTy,
did,
) => {
debug!("looking for associated item named {} for item {:?}", item_name, did);
// Checks if item_name belongs to `impl SomeItem`
let assoc_item = tcx
.inherent_impls(did)
.iter()
.flat_map(|&imp| {
tcx.associated_items(imp).find_by_name_and_namespace(
tcx,
Ident::with_dummy_span(item_name),
ns,
imp,
)
})
.map(|item| (item.kind, item.def_id))
// There should only ever be one associated item that matches from any inherent impl
.next()
// Check if item_name belongs to `impl SomeTrait for SomeItem`
// FIXME(#74563): This gives precedence to `impl SomeItem`:
// Although having both would be ambiguous, use impl version for compatibility's sake.
// To handle that properly resolve() would have to support
// something like [`ambi_fn`](<SomeStruct as SomeTrait>::ambi_fn)
.or_else(|| {
let kind =
resolve_associated_trait_item(did, module_id, item_name, ns, self.cx);
debug!("got associated item kind {:?}", kind);
kind
});
if let Some((kind, id)) = assoc_item {
let out = match kind {
ty::AssocKind::Fn => "method",
ty::AssocKind::Const => "associatedconstant",
ty::AssocKind::Type => "associatedtype",
};
// HACK(jynelson): `clean` expects the type, not the associated item
// but the disambiguator logic expects the associated item.
// Store the kind in a side channel so that only the disambiguator logic looks at it.
return Some((
root_res,
format!("{}.{}", out, item_name),
Some((kind.as_def_kind(), id)),
));
}
if ns != Namespace::ValueNS {
return None;
}
debug!("looking for variants or fields named {} for {:?}", item_name, did);
// FIXME: this doesn't really belong in `associated_item` (maybe `variant_field` is better?)
// NOTE: it's different from variant_field because it resolves fields and variants,
// not variant fields (2 path segments, not 3).
let def = match tcx.type_of(did).kind() {
ty::Adt(def, _) => def,
_ => return None,
};
let field = if def.is_enum() {
def.all_fields().find(|item| item.ident.name == item_name)
} else {
def.non_enum_variant().fields.iter().find(|item| item.ident.name == item_name)
}?;
let kind = if def.is_enum() { DefKind::Variant } else { DefKind::Field };
Some((
root_res,
format!(
"{}.{}",
if def.is_enum() { "variant" } else { "structfield" },
field.ident
),
Some((kind, field.did)),
))
}
Res::Def(DefKind::Trait, did) => tcx
.associated_items(did)
.find_by_name_and_namespace(tcx, Ident::with_dummy_span(item_name), ns, did)
.map(|item| {
let kind = match item.kind {
ty::AssocKind::Const => "associatedconstant",
ty::AssocKind::Type => "associatedtype",
ty::AssocKind::Fn => {
if item.defaultness.has_value() {
"method"
} else {
"tymethod"
}
}
};
let res = Res::Def(item.kind.as_def_kind(), item.def_id);
(res, format!("{}.{}", kind, item_name), None)
}),
_ => None,
}
}
/// Used for reporting better errors.
///
/// Returns whether the link resolved 'fully' in another namespace.
/// 'fully' here means that all parts of the link resolved, not just some path segments.
/// This returns the `Res` even if it was erroneous for some reason
/// (such as having invalid URL fragments or being in the wrong namespace).
fn check_full_res(
&mut self,
ns: Namespace,
path_str: &str,
module_id: DefId,
extra_fragment: &Option<String>,
) -> Option<Res> {
// resolve() can't be used for macro namespace
let result = match ns {
Namespace::MacroNS => self.resolve_macro(path_str, module_id).map_err(ErrorKind::from),
Namespace::TypeNS | Namespace::ValueNS => {
self.resolve(path_str, ns, module_id, extra_fragment).map(|(res, _)| res)
}
};
let res = match result {
Ok(res) => Some(res),
Err(ErrorKind::Resolve(box kind)) => kind.full_res(),
Err(ErrorKind::AnchorFailure(AnchorFailure::RustdocAnchorConflict(res))) => Some(res),
Err(ErrorKind::AnchorFailure(AnchorFailure::MultipleAnchors)) => None,
};
self.kind_side_channel.take().map(|(kind, id)| Res::Def(kind, id)).or(res)
}
}
/// Look to see if a resolved item has an associated item named `item_name`.
///
/// Given `[std::io::Error::source]`, where `source` is unresolved, this would
/// find `std::error::Error::source` and return
/// `<io::Error as error::Error>::source`.
fn resolve_associated_trait_item(
did: DefId,
module: DefId,
item_name: Symbol,
ns: Namespace,
cx: &mut DocContext<'_>,
) -> Option<(ty::AssocKind, DefId)> {
// FIXME: this should also consider blanket impls (`impl<T> X for T`). Unfortunately
// `get_auto_trait_and_blanket_impls` is broken because the caching behavior is wrong. In the
// meantime, just don't look for these blanket impls.
// Next consider explicit impls: `impl MyTrait for MyType`
// Give precedence to inherent impls.
let traits = traits_implemented_by(cx, did, module);
debug!("considering traits {:?}", traits);
let mut candidates = traits.iter().filter_map(|&trait_| {
cx.tcx
.associated_items(trait_)
.find_by_name_and_namespace(cx.tcx, Ident::with_dummy_span(item_name), ns, trait_)
.map(|assoc| (assoc.kind, assoc.def_id))
});
// FIXME(#74563): warn about ambiguity
debug!("the candidates were {:?}", candidates.clone().collect::<Vec<_>>());
candidates.next()
}
/// Given a type, return all traits in scope in `module` implemented by that type.
///
/// NOTE: this cannot be a query because more traits could be available when more crates are compiled!
/// So it is not stable to serialize cross-crate.
fn traits_implemented_by(cx: &mut DocContext<'_>, type_: DefId, module: DefId) -> FxHashSet<DefId> {
let mut resolver = cx.resolver.borrow_mut();
let in_scope_traits = cx.module_trait_cache.entry(module).or_insert_with(|| {
resolver.access(|resolver| {
let parent_scope = &ParentScope::module(resolver.get_module(module), resolver);
resolver
.traits_in_scope(None, parent_scope, SyntaxContext::root(), None)
.into_iter()
.map(|candidate| candidate.def_id)
.collect()
})
});
let tcx = cx.tcx;
let ty = tcx.type_of(type_);
let iter = in_scope_traits.iter().flat_map(|&trait_| {
trace!("considering explicit impl for trait {:?}", trait_);
// Look at each trait implementation to see if it's an impl for `did`
tcx.find_map_relevant_impl(trait_, ty, |impl_| {
let trait_ref = tcx.impl_trait_ref(impl_).expect("this is not an inherent impl");
// Check if these are the same type.
let impl_type = trait_ref.self_ty();
trace!(
"comparing type {} with kind {:?} against type {:?}",
impl_type,
impl_type.kind(),
type_
);
// Fast path: if this is a primitive simple `==` will work
let saw_impl = impl_type == ty
|| match impl_type.kind() {
// Check if these are the same def_id
ty::Adt(def, _) => {
debug!("adt def_id: {:?}", def.did);
def.did == type_
}
ty::Foreign(def_id) => *def_id == type_,
_ => false,
};
if saw_impl { Some(trait_) } else { None }
})
});
iter.collect()
}
/// Check for resolve collisions between a trait and its derive.
///
/// These are common and we should just resolve to the trait in that case.
fn is_derive_trait_collision<T>(ns: &PerNS<Result<(Res, T), ResolutionFailure<'_>>>) -> bool {
matches!(
*ns,
PerNS {
type_ns: Ok((Res::Def(DefKind::Trait, _), _)),
macro_ns: Ok((Res::Def(DefKind::Macro(MacroKind::Derive), _), _)),
..
}
)
}
impl<'a, 'tcx> DocFolder for LinkCollector<'a, 'tcx> {
fn fold_item(&mut self, item: Item) -> Option<Item> {
use rustc_middle::ty::DefIdTree;
let parent_node = if item.is_fake() {
None
} else {
find_nearest_parent_module(self.cx.tcx, item.def_id)
};
if parent_node.is_some() {
trace!("got parent node for {:?} {:?}, id {:?}", item.type_(), item.name, item.def_id);
}
// find item's parent to resolve `Self` in item's docs below
debug!("looking for the `Self` type");
let self_id = if item.is_fake() {
None
// Checking if the item is a field in an enum variant
} else if (matches!(self.cx.tcx.def_kind(item.def_id), DefKind::Field)
&& matches!(
self.cx.tcx.def_kind(self.cx.tcx.parent(item.def_id).unwrap()),
DefKind::Variant
))
{
self.cx.tcx.parent(item.def_id).and_then(|item_id| self.cx.tcx.parent(item_id))
} else if matches!(
self.cx.tcx.def_kind(item.def_id),
DefKind::AssocConst
| DefKind::AssocFn
| DefKind::AssocTy
| DefKind::Variant
| DefKind::Field
) {
self.cx.tcx.parent(item.def_id)
// HACK(jynelson): `clean` marks associated types as `TypedefItem`, not as `AssocTypeItem`.
// Fixing this breaks `fn render_deref_methods`.
// As a workaround, see if the parent of the item is an `impl`; if so this must be an associated item,
// regardless of what rustdoc wants to call it.
} else if let Some(parent) = self.cx.tcx.parent(item.def_id) {
let parent_kind = self.cx.tcx.def_kind(parent);
Some(if parent_kind == DefKind::Impl { parent } else { item.def_id })
} else {
Some(item.def_id)
};
// FIXME(jynelson): this shouldn't go through stringification, rustdoc should just use the DefId directly
let self_name = self_id.and_then(|self_id| {
if matches!(self.cx.tcx.def_kind(self_id), DefKind::Impl) {
// using `ty.to_string()` (or any variant) has issues with raw idents
let ty = self.cx.tcx.type_of(self_id);
let name = match ty.kind() {
ty::Adt(def, _) => Some(self.cx.tcx.item_name(def.did).to_string()),
other if other.is_primitive() => Some(ty.to_string()),
_ => None,
};
debug!("using type_of(): {:?}", name);
name
} else {
let name = self.cx.tcx.opt_item_name(self_id).map(|sym| sym.to_string());
debug!("using item_name(): {:?}", name);
name
}
});
let inner_docs = item.inner_docs(self.cx.tcx);
if item.is_mod() && inner_docs {
self.mod_ids.push(item.def_id);
}
// We want to resolve in the lexical scope of the documentation.
// In the presence of re-exports, this is not the same as the module of the item.
// Rather than merging all documentation into one, resolve it one attribute at a time
// so we know which module it came from.
for (parent_module, doc) in item.attrs.collapsed_doc_value_by_module_level() {
debug!("combined_docs={}", doc);
let (krate, parent_node) = if let Some(id) = parent_module {
(id.krate, Some(id))
} else {
(item.def_id.krate, parent_node)
};
// NOTE: if there are links that start in one crate and end in another, this will not resolve them.
// This is a degenerate case and it's not supported by rustdoc.
for md_link in markdown_links(&doc) {
let link = self.resolve_link(&item, &doc, &self_name, parent_node, krate, md_link);
if let Some(link) = link {
self.cx.cache.intra_doc_links.entry(item.def_id).or_default().push(link);
}
}
}
Some(if item.is_mod() {
if !inner_docs {
self.mod_ids.push(item.def_id);
}
let ret = self.fold_item_recur(item);
self.mod_ids.pop();
ret
} else {
self.fold_item_recur(item)
})
}
}
enum PreprocessingError<'a> {
Anchor(AnchorFailure),
Disambiguator(Range<usize>, String),
Resolution(ResolutionFailure<'a>, String, Option<Disambiguator>),
}
impl From<AnchorFailure> for PreprocessingError<'_> {
fn from(err: AnchorFailure) -> Self {
Self::Anchor(err)
}
}
struct PreprocessingInfo {
path_str: String,
disambiguator: Option<Disambiguator>,
extra_fragment: Option<String>,
link_text: String,
}
/// Returns:
/// - `None` if the link should be ignored.
/// - `Some(Err)` if the link should emit an error
/// - `Some(Ok)` if the link is valid
///
/// `link_buffer` is needed for lifetime reasons; it will always be overwritten and the contents ignored.
fn preprocess_link<'a>(
ori_link: &'a MarkdownLink,
) -> Option<Result<PreprocessingInfo, PreprocessingError<'a>>> {
// [] is mostly likely not supposed to be a link
if ori_link.link.is_empty() {
return None;
}
// Bail early for real links.
if ori_link.link.contains('/') {
return None;
}
let stripped = ori_link.link.replace("`", "");
let mut parts = stripped.split('#');
let link = parts.next().unwrap();
if link.trim().is_empty() {
// This is an anchor to an element of the current page, nothing to do in here!
return None;
}
let extra_fragment = parts.next();
if parts.next().is_some() {
// A valid link can't have multiple #'s
return Some(Err(AnchorFailure::MultipleAnchors.into()));
}
// Parse and strip the disambiguator from the link, if present.
let (path_str, disambiguator) = match Disambiguator::from_str(&link) {
Ok(Some((d, path))) => (path.trim(), Some(d)),
Ok(None) => (link.trim(), None),
Err((err_msg, relative_range)) => {
// Only report error if we would not have ignored this link. See issue #83859.
if !should_ignore_link_with_disambiguators(link) {
let no_backticks_range = range_between_backticks(&ori_link);
let disambiguator_range = (no_backticks_range.start + relative_range.start)
..(no_backticks_range.start + relative_range.end);
return Some(Err(PreprocessingError::Disambiguator(disambiguator_range, err_msg)));
} else {
return None;
}
}
};
if should_ignore_link(path_str) {
return None;
}
// We stripped `()` and `!` when parsing the disambiguator.
// Add them back to be displayed, but not prefix disambiguators.
let link_text =
disambiguator.map(|d| d.display_for(path_str)).unwrap_or_else(|| path_str.to_owned());
// Strip generics from the path.
let path_str = if path_str.contains(['<', '>'].as_slice()) {
match strip_generics_from_path(&path_str) {
Ok(path) => path,
Err(err_kind) => {
debug!("link has malformed generics: {}", path_str);
return Some(Err(PreprocessingError::Resolution(
err_kind,
path_str.to_owned(),
disambiguator,
)));
}
}
} else {
path_str.to_owned()
};
// Sanity check to make sure we don't have any angle brackets after stripping generics.
assert!(!path_str.contains(['<', '>'].as_slice()));
// The link is not an intra-doc link if it still contains spaces after stripping generics.
if path_str.contains(' ') {
return None;
}
Some(Ok(PreprocessingInfo {
path_str,
disambiguator,
extra_fragment: extra_fragment.map(String::from),
link_text,
}))
}
impl LinkCollector<'_, '_> {
/// This is the entry point for resolving an intra-doc link.
///
/// FIXME(jynelson): this is way too many arguments
fn resolve_link(
&mut self,
item: &Item,
dox: &str,
self_name: &Option<String>,
parent_node: Option<DefId>,
krate: CrateNum,
ori_link: MarkdownLink,
) -> Option<ItemLink> {
trace!("considering link '{}'", ori_link.link);
let diag_info = DiagnosticInfo {
item,
dox,
ori_link: &ori_link.link,
link_range: ori_link.range.clone(),
};
let PreprocessingInfo { path_str, disambiguator, extra_fragment, link_text } =
match preprocess_link(&ori_link)? {
Ok(x) => x,
Err(err) => {
match err {
PreprocessingError::Anchor(err) => anchor_failure(self.cx, diag_info, err),
PreprocessingError::Disambiguator(range, msg) => {
disambiguator_error(self.cx, diag_info, range, &msg)
}
PreprocessingError::Resolution(err, path_str, disambiguator) => {
resolution_failure(
self,
diag_info,
&path_str,
disambiguator,
smallvec![err],
);
}
}
return None;
}
};
let mut path_str = &*path_str;
let inner_docs = item.inner_docs(self.cx.tcx);
// In order to correctly resolve intra-doc links we need to
// pick a base AST node to work from. If the documentation for
// this module came from an inner comment (//!) then we anchor
// our name resolution *inside* the module. If, on the other
// hand it was an outer comment (///) then we anchor the name
// resolution in the parent module on the basis that the names
// used are more likely to be intended to be parent names. For
// this, we set base_node to None for inner comments since
// we've already pushed this node onto the resolution stack but
// for outer comments we explicitly try and resolve against the
// parent_node first.
let base_node =
if item.is_mod() && inner_docs { self.mod_ids.last().copied() } else { parent_node };
let mut module_id = if let Some(id) = base_node {
id
} else {
// This is a bug.
debug!("attempting to resolve item without parent module: {}", path_str);
resolution_failure(
self,
diag_info,
path_str,
disambiguator,
smallvec![ResolutionFailure::NoParentItem],
);
return None;
};
let resolved_self;
// replace `Self` with suitable item's parent name
let is_lone_self = path_str == "Self";
let is_lone_crate = path_str == "crate";
if path_str.starts_with("Self::") || is_lone_self {
if let Some(ref name) = self_name {
if is_lone_self {
path_str = name;
} else {
resolved_self = format!("{}::{}", name, &path_str[6..]);
path_str = &resolved_self;
}
}
} else if path_str.starts_with("crate::") || is_lone_crate {
use rustc_span::def_id::CRATE_DEF_INDEX;
// HACK(jynelson): rustc_resolve thinks that `crate` is the crate currently being documented.
// But rustdoc wants it to mean the crate this item was originally present in.
// To work around this, remove it and resolve relative to the crate root instead.
// HACK(jynelson)(2): If we just strip `crate::` then suddenly primitives become ambiguous
// (consider `crate::char`). Instead, change it to `self::`. This works because 'self' is now the crate root.
// FIXME(#78696): This doesn't always work.
if is_lone_crate {
path_str = "self";
} else {
resolved_self = format!("self::{}", &path_str["crate::".len()..]);
path_str = &resolved_self;
}
module_id = DefId { krate, index: CRATE_DEF_INDEX };
}
let (mut res, mut fragment) = self.resolve_with_disambiguator_cached(
ResolutionInfo {
module_id,
dis: disambiguator,
path_str: path_str.to_owned(),
extra_fragment: extra_fragment.map(String::from),
},
diag_info.clone(), // this struct should really be Copy, but Range is not :(
matches!(ori_link.kind, LinkType::Reference | LinkType::Shortcut),
)?;
// Check for a primitive which might conflict with a module
// Report the ambiguity and require that the user specify which one they meant.
// FIXME: could there ever be a primitive not in the type namespace?
if matches!(
disambiguator,
None | Some(Disambiguator::Namespace(Namespace::TypeNS) | Disambiguator::Primitive)
) && !matches!(res, Res::Primitive(_))
{
if let Some(prim) = resolve_primitive(path_str, TypeNS) {
// `prim@char`
if matches!(disambiguator, Some(Disambiguator::Primitive)) {
if fragment.is_some() {
anchor_failure(
self.cx,
diag_info,
AnchorFailure::RustdocAnchorConflict(prim),
);
return None;
}
res = prim;
fragment = Some(prim.name(self.cx.tcx));
} else {
// `[char]` when a `char` module is in scope
let candidates = vec![res, prim];
ambiguity_error(self.cx, diag_info, path_str, candidates);
return None;
}
}
}
let report_mismatch = |specified: Disambiguator, resolved: Disambiguator| {
// The resolved item did not match the disambiguator; give a better error than 'not found'
let msg = format!("incompatible link kind for `{}`", path_str);
let callback = |diag: &mut DiagnosticBuilder<'_>, sp| {
let note = format!(
"this link resolved to {} {}, which is not {} {}",
resolved.article(),
resolved.descr(),
specified.article(),
specified.descr()
);
diag.note(&note);
suggest_disambiguator(resolved, diag, path_str, dox, sp, &ori_link.range);
};
report_diagnostic(self.cx.tcx, BROKEN_INTRA_DOC_LINKS, &msg, &diag_info, callback);
};
let verify = |kind: DefKind, id: DefId| {
let (kind, id) = self.kind_side_channel.take().unwrap_or((kind, id));
debug!("intra-doc link to {} resolved to {:?} (id: {:?})", path_str, res, id);
// Disallow e.g. linking to enums with `struct@`
debug!("saw kind {:?} with disambiguator {:?}", kind, disambiguator);
match (kind, disambiguator) {
| (DefKind::Const | DefKind::ConstParam | DefKind::AssocConst | DefKind::AnonConst, Some(Disambiguator::Kind(DefKind::Const)))
// NOTE: this allows 'method' to mean both normal functions and associated functions
// This can't cause ambiguity because both are in the same namespace.
| (DefKind::Fn | DefKind::AssocFn, Some(Disambiguator::Kind(DefKind::Fn)))
// These are namespaces; allow anything in the namespace to match
| (_, Some(Disambiguator::Namespace(_)))
// If no disambiguator given, allow anything
| (_, None)
// All of these are valid, so do nothing
=> {}
(actual, Some(Disambiguator::Kind(expected))) if actual == expected => {}
(_, Some(specified @ Disambiguator::Kind(_) | specified @ Disambiguator::Primitive)) => {
report_mismatch(specified, Disambiguator::Kind(kind));
return None;
}
}
// item can be non-local e.g. when using #[doc(primitive = "pointer")]
if let Some((src_id, dst_id)) = id
.as_local()
.and_then(|dst_id| item.def_id.as_local().map(|src_id| (src_id, dst_id)))
{
use rustc_hir::def_id::LOCAL_CRATE;
let hir_src = self.cx.tcx.hir().local_def_id_to_hir_id(src_id);
let hir_dst = self.cx.tcx.hir().local_def_id_to_hir_id(dst_id);
if self.cx.tcx.privacy_access_levels(LOCAL_CRATE).is_exported(hir_src)
&& !self.cx.tcx.privacy_access_levels(LOCAL_CRATE).is_exported(hir_dst)
{
privacy_error(self.cx, &diag_info, &path_str);
}
}
Some(())
};
match res {
Res::Primitive(prim) => {
if let Some((kind, id)) = self.kind_side_channel.take() {
// We're actually resolving an associated item of a primitive, so we need to
// verify the disambiguator (if any) matches the type of the associated item.
// This case should really follow the same flow as the `Res::Def` branch below,
// but attempting to add a call to `clean::register_res` causes an ICE. @jyn514
// thinks `register_res` is only needed for cross-crate re-exports, but Rust
// doesn't allow statements like `use str::trim;`, making this a (hopefully)
// valid omission. See https://github.com/rust-lang/rust/pull/80660#discussion_r551585677
// for discussion on the matter.
verify(kind, id)?;
// FIXME: it would be nice to check that the feature gate was enabled in the original crate, not just ignore it altogether.
// However I'm not sure how to check that across crates.
if prim == PrimitiveType::RawPointer
&& item.def_id.is_local()
&& !self.cx.tcx.features().intra_doc_pointers
{
let span = super::source_span_for_markdown_range(
self.cx.tcx,
dox,
&ori_link.range,
&item.attrs,
)
.unwrap_or_else(|| item.attr_span(self.cx.tcx));
rustc_session::parse::feature_err(
&self.cx.tcx.sess.parse_sess,
sym::intra_doc_pointers,
span,
"linking to associated items of raw pointers is experimental",
)
.note("rustdoc does not allow disambiguating between `*const` and `*mut`, and pointers are unstable until it does")
.emit();
}
} else {
match disambiguator {
Some(Disambiguator::Primitive | Disambiguator::Namespace(_)) | None => {}
Some(other) => {
report_mismatch(other, Disambiguator::Primitive);
return None;
}
}
}
Some(ItemLink { link: ori_link.link, link_text, did: None, fragment })
}
Res::Def(kind, id) => {
verify(kind, id)?;
let id = clean::register_res(self.cx, rustc_hir::def::Res::Def(kind, id));
Some(ItemLink { link: ori_link.link, link_text, did: Some(id), fragment })
}
}
}
fn resolve_with_disambiguator_cached(
&mut self,
key: ResolutionInfo,
diag: DiagnosticInfo<'_>,
cache_resolution_failure: bool,
) -> Option<(Res, Option<String>)> {
// Try to look up both the result and the corresponding side channel value
if let Some(ref cached) = self.visited_links.get(&key) {
match cached {
Some(cached) => {
self.kind_side_channel.set(cached.side_channel.clone());
return Some(cached.res.clone());
}
None if cache_resolution_failure => return None,
None => {
// Although we hit the cache and found a resolution error, this link isn't
// supposed to cache those. Run link resolution again to emit the expected
// resolution error.
}
}
}
let res = self.resolve_with_disambiguator(&key, diag);
// Cache only if resolved successfully - don't silence duplicate errors
if let Some(res) = res {
// Store result for the actual namespace
self.visited_links.insert(
key,
Some(CachedLink {
res: res.clone(),
side_channel: self.kind_side_channel.clone().into_inner(),
}),
);
Some(res)
} else {
if cache_resolution_failure {
// For reference-style links we only want to report one resolution error
// so let's cache them as well.
self.visited_links.insert(key, None);
}
None
}
}
/// After parsing the disambiguator, resolve the main part of the link.
// FIXME(jynelson): wow this is just so much
fn resolve_with_disambiguator(
&mut self,
key: &ResolutionInfo,
diag: DiagnosticInfo<'_>,
) -> Option<(Res, Option<String>)> {
let disambiguator = key.dis;
let path_str = &key.path_str;
let base_node = key.module_id;
let extra_fragment = &key.extra_fragment;
match disambiguator.map(Disambiguator::ns) {
Some(expected_ns @ (ValueNS | TypeNS)) => {
match self.resolve(path_str, expected_ns, base_node, extra_fragment) {
Ok(res) => Some(res),
Err(ErrorKind::Resolve(box mut kind)) => {
// We only looked in one namespace. Try to give a better error if possible.
if kind.full_res().is_none() {
let other_ns = if expected_ns == ValueNS { TypeNS } else { ValueNS };
// FIXME: really it should be `resolution_failure` that does this, not `resolve_with_disambiguator`
// See https://github.com/rust-lang/rust/pull/76955#discussion_r493953382 for a good approach
for &new_ns in &[other_ns, MacroNS] {
if let Some(res) =
self.check_full_res(new_ns, path_str, base_node, extra_fragment)
{
kind = ResolutionFailure::WrongNamespace { res, expected_ns };
break;
}
}
}
resolution_failure(self, diag, path_str, disambiguator, smallvec![kind]);
// This could just be a normal link or a broken link
// we could potentially check if something is
// "intra-doc-link-like" and warn in that case.
None
}
Err(ErrorKind::AnchorFailure(msg)) => {
anchor_failure(self.cx, diag, msg);
None
}
}
}
None => {
// Try everything!
let mut candidates = PerNS {
macro_ns: self
.resolve_macro(path_str, base_node)
.map(|res| (res, extra_fragment.clone())),
type_ns: match self.resolve(path_str, TypeNS, base_node, extra_fragment) {
Ok(res) => {
debug!("got res in TypeNS: {:?}", res);
Ok(res)
}
Err(ErrorKind::AnchorFailure(msg)) => {
anchor_failure(self.cx, diag, msg);
return None;
}
Err(ErrorKind::Resolve(box kind)) => Err(kind),
},
value_ns: match self.resolve(path_str, ValueNS, base_node, extra_fragment) {
Ok(res) => Ok(res),
Err(ErrorKind::AnchorFailure(msg)) => {
anchor_failure(self.cx, diag, msg);
return None;
}
Err(ErrorKind::Resolve(box kind)) => Err(kind),
}
.and_then(|(res, fragment)| {
// Constructors are picked up in the type namespace.
match res {
Res::Def(DefKind::Ctor(..), _) => {
Err(ResolutionFailure::WrongNamespace { res, expected_ns: TypeNS })
}
_ => {
match (fragment, extra_fragment.clone()) {
(Some(fragment), Some(_)) => {
// Shouldn't happen but who knows?
Ok((res, Some(fragment)))
}
(fragment, None) | (None, fragment) => Ok((res, fragment)),
}
}
}
}),
};
let len = candidates.iter().filter(|res| res.is_ok()).count();
if len == 0 {
resolution_failure(
self,
diag,
path_str,
disambiguator,
candidates.into_iter().filter_map(|res| res.err()).collect(),
);
// this could just be a normal link
return None;
}
if len == 1 {
Some(candidates.into_iter().filter_map(|res| res.ok()).next().unwrap())
} else if len == 2 && is_derive_trait_collision(&candidates) {
Some(candidates.type_ns.unwrap())
} else {
if is_derive_trait_collision(&candidates) {
candidates.macro_ns = Err(ResolutionFailure::Dummy);
}
// If we're reporting an ambiguity, don't mention the namespaces that failed
let candidates = candidates.map(|candidate| candidate.ok().map(|(res, _)| res));
ambiguity_error(self.cx, diag, path_str, candidates.present_items().collect());
None
}
}
Some(MacroNS) => {
match self.resolve_macro(path_str, base_node) {
Ok(res) => Some((res, extra_fragment.clone())),
Err(mut kind) => {
// `resolve_macro` only looks in the macro namespace. Try to give a better error if possible.
for &ns in &[TypeNS, ValueNS] {
if let Some(res) =
self.check_full_res(ns, path_str, base_node, extra_fragment)
{
kind =
ResolutionFailure::WrongNamespace { res, expected_ns: MacroNS };
break;
}
}
resolution_failure(self, diag, path_str, disambiguator, smallvec![kind]);
None
}
}
}
}
}
}
/// Get the section of a link between the backticks,
/// or the whole link if there aren't any backticks.
///
/// For example:
///
/// ```text
/// [`Foo`]
/// ^^^
/// ```
fn range_between_backticks(ori_link: &MarkdownLink) -> Range<usize> {
let after_first_backtick_group = ori_link.link.bytes().position(|b| b != b'`').unwrap_or(0);
let before_second_backtick_group = ori_link
.link
.bytes()
.skip(after_first_backtick_group)
.position(|b| b == b'`')
.unwrap_or(ori_link.link.len());
(ori_link.range.start + after_first_backtick_group)
..(ori_link.range.start + before_second_backtick_group)
}
/// Returns true if we should ignore `link` due to it being unlikely
/// that it is an intra-doc link. `link` should still have disambiguators
/// if there were any.
///
/// The difference between this and [`should_ignore_link()`] is that this
/// check should only be used on links that still have disambiguators.
fn should_ignore_link_with_disambiguators(link: &str) -> bool {
link.contains(|ch: char| !(ch.is_alphanumeric() || ":_<>, !*&;@()".contains(ch)))
}
/// Returns true if we should ignore `path_str` due to it being unlikely
/// that it is an intra-doc link.
fn should_ignore_link(path_str: &str) -> bool {
path_str.contains(|ch: char| !(ch.is_alphanumeric() || ":_<>, !*&;".contains(ch)))
}
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
/// Disambiguators for a link.
enum Disambiguator {
/// `prim@`
///
/// This is buggy, see <https://github.com/rust-lang/rust/pull/77875#discussion_r503583103>
Primitive,
/// `struct@` or `f()`
Kind(DefKind),
/// `type@`
Namespace(Namespace),
}
impl Disambiguator {
/// The text that should be displayed when the path is rendered as HTML.
///
/// NOTE: `path` is not the original link given by the user, but a name suitable for passing to `resolve`.
fn display_for(&self, path: &str) -> String {
match self {
// FIXME: this will have different output if the user had `m!()` originally.
Self::Kind(DefKind::Macro(MacroKind::Bang)) => format!("{}!", path),
Self::Kind(DefKind::Fn) => format!("{}()", path),
_ => path.to_owned(),
}
}
/// Given a link, parse and return `(disambiguator, path_str)`.
///
/// This returns `Ok(Some(...))` if a disambiguator was found,
/// `Ok(None)` if no disambiguator was found, or `Err(...)`
/// if there was a problem with the disambiguator.
fn from_str(link: &str) -> Result<Option<(Self, &str)>, (String, Range<usize>)> {
use Disambiguator::{Kind, Namespace as NS, Primitive};
if let Some(idx) = link.find('@') {
let (prefix, rest) = link.split_at(idx);
let d = match prefix {
"struct" => Kind(DefKind::Struct),
"enum" => Kind(DefKind::Enum),
"trait" => Kind(DefKind::Trait),
"union" => Kind(DefKind::Union),
"module" | "mod" => Kind(DefKind::Mod),
"const" | "constant" => Kind(DefKind::Const),
"static" => Kind(DefKind::Static),
"function" | "fn" | "method" => Kind(DefKind::Fn),
"derive" => Kind(DefKind::Macro(MacroKind::Derive)),
"type" => NS(Namespace::TypeNS),
"value" => NS(Namespace::ValueNS),
"macro" => NS(Namespace::MacroNS),
"prim" | "primitive" => Primitive,
_ => return Err((format!("unknown disambiguator `{}`", prefix), 0..idx)),
};
Ok(Some((d, &rest[1..])))
} else {
let suffixes = [
("!()", DefKind::Macro(MacroKind::Bang)),
("()", DefKind::Fn),
("!", DefKind::Macro(MacroKind::Bang)),
];
for &(suffix, kind) in &suffixes {
if let Some(link) = link.strip_suffix(suffix) {
// Avoid turning `!` or `()` into an empty string
if !link.is_empty() {
return Ok(Some((Kind(kind), link)));
}
}
}
Ok(None)
}
}
fn from_res(res: Res) -> Self {
match res {
Res::Def(kind, _) => Disambiguator::Kind(kind),
Res::Primitive(_) => Disambiguator::Primitive,
}
}
/// Used for error reporting.
fn suggestion(self) -> Suggestion {
let kind = match self {
Disambiguator::Primitive => return Suggestion::Prefix("prim"),
Disambiguator::Kind(kind) => kind,
Disambiguator::Namespace(_) => panic!("display_for cannot be used on namespaces"),
};
if kind == DefKind::Macro(MacroKind::Bang) {
return Suggestion::Macro;
} else if kind == DefKind::Fn || kind == DefKind::AssocFn {
return Suggestion::Function;
}
let prefix = match kind {
DefKind::Struct => "struct",
DefKind::Enum => "enum",
DefKind::Trait => "trait",
DefKind::Union => "union",
DefKind::Mod => "mod",
DefKind::Const | DefKind::ConstParam | DefKind::AssocConst | DefKind::AnonConst => {
"const"
}
DefKind::Static => "static",
DefKind::Macro(MacroKind::Derive) => "derive",
// Now handle things that don't have a specific disambiguator
_ => match kind
.ns()
.expect("tried to calculate a disambiguator for a def without a namespace?")
{
Namespace::TypeNS => "type",
Namespace::ValueNS => "value",
Namespace::MacroNS => "macro",
},
};
Suggestion::Prefix(prefix)
}
fn ns(self) -> Namespace {
match self {
Self::Namespace(n) => n,
Self::Kind(k) => {
k.ns().expect("only DefKinds with a valid namespace can be disambiguators")
}
Self::Primitive => TypeNS,
}
}
fn article(self) -> &'static str {
match self {
Self::Namespace(_) => panic!("article() doesn't make sense for namespaces"),
Self::Kind(k) => k.article(),
Self::Primitive => "a",
}
}
fn descr(self) -> &'static str {
match self {
Self::Namespace(n) => n.descr(),
// HACK(jynelson): by looking at the source I saw the DefId we pass
// for `expected.descr()` doesn't matter, since it's not a crate
Self::Kind(k) => k.descr(DefId::local(hir::def_id::DefIndex::from_usize(0))),
Self::Primitive => "builtin type",
}
}
}
/// A suggestion to show in a diagnostic.
enum Suggestion {
/// `struct@`
Prefix(&'static str),
/// `f()`
Function,
/// `m!`
Macro,
}
impl Suggestion {
fn descr(&self) -> Cow<'static, str> {
match self {
Self::Prefix(x) => format!("prefix with `{}@`", x).into(),
Self::Function => "add parentheses".into(),
Self::Macro => "add an exclamation mark".into(),
}
}
fn as_help(&self, path_str: &str) -> String {
// FIXME: if this is an implied shortcut link, it's bad style to suggest `@`
match self {
Self::Prefix(prefix) => format!("{}@{}", prefix, path_str),
Self::Function => format!("{}()", path_str),
Self::Macro => format!("{}!", path_str),
}
}
}
/// Reports a diagnostic for an intra-doc link.
///
/// If no link range is provided, or the source span of the link cannot be determined, the span of
/// the entire documentation block is used for the lint. If a range is provided but the span
/// calculation fails, a note is added to the diagnostic pointing to the link in the markdown.
///
/// The `decorate` callback is invoked in all cases to allow further customization of the
/// diagnostic before emission. If the span of the link was able to be determined, the second
/// parameter of the callback will contain it, and the primary span of the diagnostic will be set
/// to it.
fn report_diagnostic(
tcx: TyCtxt<'_>,
lint: &'static Lint,
msg: &str,
DiagnosticInfo { item, ori_link: _, dox, link_range }: &DiagnosticInfo<'_>,
decorate: impl FnOnce(&mut DiagnosticBuilder<'_>, Option<rustc_span::Span>),
) {
let hir_id = match DocContext::as_local_hir_id(tcx, item.def_id) {
Some(hir_id) => hir_id,
None => {
// If non-local, no need to check anything.
info!("ignoring warning from parent crate: {}", msg);
return;
}
};
let sp = item.attr_span(tcx);
tcx.struct_span_lint_hir(lint, hir_id, sp, |lint| {
let mut diag = lint.build(msg);
let span = super::source_span_for_markdown_range(tcx, dox, link_range, &item.attrs);
if let Some(sp) = span {
diag.set_span(sp);
} else {
// blah blah blah\nblah\nblah [blah] blah blah\nblah blah
// ^ ~~~~
// | link_range
// last_new_line_offset
let last_new_line_offset = dox[..link_range.start].rfind('\n').map_or(0, |n| n + 1);
let line = dox[last_new_line_offset..].lines().next().unwrap_or("");
// Print the line containing the `link_range` and manually mark it with '^'s.
diag.note(&format!(
"the link appears in this line:\n\n{line}\n\
{indicator: <before$}{indicator:^<found$}",
line = line,
indicator = "",
before = link_range.start - last_new_line_offset,
found = link_range.len(),
));
}
decorate(&mut diag, span);
diag.emit();
});
}
/// Reports a link that failed to resolve.
///
/// This also tries to resolve any intermediate path segments that weren't
/// handled earlier. For example, if passed `Item::Crate(std)` and `path_str`
/// `std::io::Error::x`, this will resolve `std::io::Error`.
fn resolution_failure(
collector: &mut LinkCollector<'_, '_>,
diag_info: DiagnosticInfo<'_>,
path_str: &str,
disambiguator: Option<Disambiguator>,
kinds: SmallVec<[ResolutionFailure<'_>; 3]>,
) {
let tcx = collector.cx.tcx;
report_diagnostic(
tcx,
BROKEN_INTRA_DOC_LINKS,
&format!("unresolved link to `{}`", path_str),
&diag_info,
|diag, sp| {
let item = |res: Res| format!("the {} `{}`", res.descr(), res.name(tcx),);
let assoc_item_not_allowed = |res: Res| {
let name = res.name(tcx);
format!(
"`{}` is {} {}, not a module or type, and cannot have associated items",
name,
res.article(),
res.descr()
)
};
// ignore duplicates
let mut variants_seen = SmallVec::<[_; 3]>::new();
for mut failure in kinds {
let variant = std::mem::discriminant(&failure);
if variants_seen.contains(&variant) {
continue;
}
variants_seen.push(variant);
if let ResolutionFailure::NotResolved { module_id, partial_res, unresolved } =
&mut failure
{
use DefKind::*;
let module_id = *module_id;
// FIXME(jynelson): this might conflict with my `Self` fix in #76467
// FIXME: maybe use itertools `collect_tuple` instead?
fn split(path: &str) -> Option<(&str, &str)> {
let mut splitter = path.rsplitn(2, "::");
splitter.next().and_then(|right| splitter.next().map(|left| (left, right)))
}
// Check if _any_ parent of the path gets resolved.
// If so, report it and say the first which failed; if not, say the first path segment didn't resolve.
let mut name = path_str;
'outer: loop {
let (start, end) = if let Some(x) = split(name) {
x
} else {
// avoid bug that marked [Quux::Z] as missing Z, not Quux
if partial_res.is_none() {
*unresolved = name.into();
}
break;
};
name = start;
for &ns in &[TypeNS, ValueNS, MacroNS] {
if let Some(res) =
collector.check_full_res(ns, &start, module_id, &None)
{
debug!("found partial_res={:?}", res);
*partial_res = Some(res);
*unresolved = end.into();
break 'outer;
}
}
*unresolved = end.into();
}
let last_found_module = match *partial_res {
Some(Res::Def(DefKind::Mod, id)) => Some(id),
None => Some(module_id),
_ => None,
};
// See if this was a module: `[path]` or `[std::io::nope]`
if let Some(module) = last_found_module {
let note = if partial_res.is_some() {
// Part of the link resolved; e.g. `std::io::nonexistent`
let module_name = tcx.item_name(module);
format!("no item named `{}` in module `{}`", unresolved, module_name)
} else {
// None of the link resolved; e.g. `Notimported`
format!("no item named `{}` in scope", unresolved)
};
if let Some(span) = sp {
diag.span_label(span, &note);
} else {
diag.note(&note);
}
// If the link has `::` in it, assume it was meant to be an intra-doc link.
// Otherwise, the `[]` might be unrelated.
// FIXME: don't show this for autolinks (`<>`), `()` style links, or reference links
if !path_str.contains("::") {
diag.help(r#"to escape `[` and `]` characters, add '\' before them like `\[` or `\]`"#);
}
continue;
}
// Otherwise, it must be an associated item or variant
let res = partial_res.expect("None case was handled by `last_found_module`");
let name = res.name(tcx);
let kind = match res {
Res::Def(kind, _) => Some(kind),
Res::Primitive(_) => None,
};
let path_description = if let Some(kind) = kind {
match kind {
Mod | ForeignMod => "inner item",
Struct => "field or associated item",
Enum | Union => "variant or associated item",
Variant
| Field
| Closure
| Generator
| AssocTy
| AssocConst
| AssocFn
| Fn
| Macro(_)
| Const
| ConstParam
| ExternCrate
| Use
| LifetimeParam
| Ctor(_, _)
| AnonConst => {
let note = assoc_item_not_allowed(res);
if let Some(span) = sp {
diag.span_label(span, &note);
} else {
diag.note(&note);
}
return;
}
Trait | TyAlias | ForeignTy | OpaqueTy | TraitAlias | TyParam
| Static => "associated item",
Impl | GlobalAsm => unreachable!("not a path"),
}
} else {
"associated item"
};
let note = format!(
"the {} `{}` has no {} named `{}`",
res.descr(),
name,
disambiguator.map_or(path_description, |d| d.descr()),
unresolved,
);
if let Some(span) = sp {
diag.span_label(span, &note);
} else {
diag.note(&note);
}
continue;
}
let note = match failure {
ResolutionFailure::NotResolved { .. } => unreachable!("handled above"),
ResolutionFailure::Dummy => continue,
ResolutionFailure::WrongNamespace { res, expected_ns } => {
if let Res::Def(kind, _) = res {
let disambiguator = Disambiguator::Kind(kind);
suggest_disambiguator(
disambiguator,
diag,
path_str,
diag_info.dox,
sp,
&diag_info.link_range,
)
}
format!(
"this link resolves to {}, which is not in the {} namespace",
item(res),
expected_ns.descr()
)
}
ResolutionFailure::NoParentItem => {
diag.level = rustc_errors::Level::Bug;
"all intra-doc links should have a parent item".to_owned()
}
ResolutionFailure::MalformedGenerics(variant) => match variant {
MalformedGenerics::UnbalancedAngleBrackets => {
String::from("unbalanced angle brackets")
}
MalformedGenerics::MissingType => {
String::from("missing type for generic parameters")
}
MalformedGenerics::HasFullyQualifiedSyntax => {
diag.note("see https://github.com/rust-lang/rust/issues/74563 for more information");
String::from("fully-qualified syntax is unsupported")
}
MalformedGenerics::InvalidPathSeparator => {
String::from("has invalid path separator")
}
MalformedGenerics::TooManyAngleBrackets => {
String::from("too many angle brackets")
}
MalformedGenerics::EmptyAngleBrackets => {
String::from("empty angle brackets")
}
},
};
if let Some(span) = sp {
diag.span_label(span, &note);
} else {
diag.note(&note);
}
}
},
);
}
/// Report an anchor failure.
fn anchor_failure(cx: &DocContext<'_>, diag_info: DiagnosticInfo<'_>, failure: AnchorFailure) {
let (msg, anchor_idx) = match failure {
AnchorFailure::MultipleAnchors => {
(format!("`{}` contains multiple anchors", diag_info.ori_link), 1)
}
AnchorFailure::RustdocAnchorConflict(res) => (
format!(
"`{}` contains an anchor, but links to {kind}s are already anchored",
diag_info.ori_link,
kind = res.descr(),
),
0,
),
};
report_diagnostic(cx.tcx, BROKEN_INTRA_DOC_LINKS, &msg, &diag_info, |diag, sp| {
if let Some(mut sp) = sp {
if let Some((fragment_offset, _)) =
diag_info.ori_link.char_indices().filter(|(_, x)| *x == '#').nth(anchor_idx)
{
sp = sp.with_lo(sp.lo() + rustc_span::BytePos(fragment_offset as _));
}
diag.span_label(sp, "invalid anchor");
}
if let AnchorFailure::RustdocAnchorConflict(Res::Primitive(_)) = failure {
diag.note("this restriction may be lifted in a future release");
diag.note("see https://github.com/rust-lang/rust/issues/83083 for more information");
}
});
}
/// Report an error in the link disambiguator.
fn disambiguator_error(
cx: &DocContext<'_>,
mut diag_info: DiagnosticInfo<'_>,
disambiguator_range: Range<usize>,
msg: &str,
) {
diag_info.link_range = disambiguator_range;
report_diagnostic(cx.tcx, BROKEN_INTRA_DOC_LINKS, msg, &diag_info, |_diag, _sp| {});
}
/// Report an ambiguity error, where there were multiple possible resolutions.
fn ambiguity_error(
cx: &DocContext<'_>,
diag_info: DiagnosticInfo<'_>,
path_str: &str,
candidates: Vec<Res>,
) {
let mut msg = format!("`{}` is ", path_str);
match candidates.as_slice() {
[first_def, second_def] => {
msg += &format!(
"both {} {} and {} {}",
first_def.article(),
first_def.descr(),
second_def.article(),
second_def.descr(),
);
}
_ => {
let mut candidates = candidates.iter().peekable();
while let Some(res) = candidates.next() {
if candidates.peek().is_some() {
msg += &format!("{} {}, ", res.article(), res.descr());
} else {
msg += &format!("and {} {}", res.article(), res.descr());
}
}
}
}
report_diagnostic(cx.tcx, BROKEN_INTRA_DOC_LINKS, &msg, &diag_info, |diag, sp| {
if let Some(sp) = sp {
diag.span_label(sp, "ambiguous link");
} else {
diag.note("ambiguous link");
}
for res in candidates {
let disambiguator = Disambiguator::from_res(res);
suggest_disambiguator(
disambiguator,
diag,
path_str,
diag_info.dox,
sp,
&diag_info.link_range,
);
}
});
}
/// In case of an ambiguity or mismatched disambiguator, suggest the correct
/// disambiguator.
fn suggest_disambiguator(
disambiguator: Disambiguator,
diag: &mut DiagnosticBuilder<'_>,
path_str: &str,
dox: &str,
sp: Option<rustc_span::Span>,
link_range: &Range<usize>,
) {
let suggestion = disambiguator.suggestion();
let help = format!("to link to the {}, {}", disambiguator.descr(), suggestion.descr());
if let Some(sp) = sp {
let msg = if dox.bytes().nth(link_range.start) == Some(b'`') {
format!("`{}`", suggestion.as_help(path_str))
} else {
suggestion.as_help(path_str)
};
diag.span_suggestion(sp, &help, msg, Applicability::MaybeIncorrect);
} else {
diag.help(&format!("{}: {}", help, suggestion.as_help(path_str)));
}
}
/// Report a link from a public item to a private one.
fn privacy_error(cx: &DocContext<'_>, diag_info: &DiagnosticInfo<'_>, path_str: &str) {
let sym;
let item_name = match diag_info.item.name {
Some(name) => {
sym = name.as_str();
&*sym
}
None => "<unknown>",
};
let msg =
format!("public documentation for `{}` links to private item `{}`", item_name, path_str);
report_diagnostic(cx.tcx, PRIVATE_INTRA_DOC_LINKS, &msg, diag_info, |diag, sp| {
if let Some(sp) = sp {
diag.span_label(sp, "this item is private");
}
let note_msg = if cx.render_options.document_private {
"this link resolves only because you passed `--document-private-items`, but will break without"
} else {
"this link will resolve properly if you pass `--document-private-items`"
};
diag.note(note_msg);
});
}
/// Given an enum variant's res, return the res of its enum and the associated fragment.
fn handle_variant(
cx: &DocContext<'_>,
res: Res,
extra_fragment: &Option<String>,
) -> Result<(Res, Option<String>), ErrorKind<'static>> {
use rustc_middle::ty::DefIdTree;
if extra_fragment.is_some() {
return Err(ErrorKind::AnchorFailure(AnchorFailure::RustdocAnchorConflict(res)));
}
cx.tcx
.parent(res.def_id())
.map(|parent| {
let parent_def = Res::Def(DefKind::Enum, parent);
let variant = cx.tcx.expect_variant_res(res.as_hir_res().unwrap());
(parent_def, Some(format!("variant.{}", variant.ident.name)))
})
.ok_or_else(|| ResolutionFailure::NoParentItem.into())
}
/// Resolve a primitive type or value.
fn resolve_primitive(path_str: &str, ns: Namespace) -> Option<Res> {
if ns != TypeNS {
return None;
}
use PrimitiveType::*;
let prim = match path_str {
"isize" => Isize,
"i8" => I8,
"i16" => I16,
"i32" => I32,
"i64" => I64,
"i128" => I128,
"usize" => Usize,
"u8" => U8,
"u16" => U16,
"u32" => U32,
"u64" => U64,
"u128" => U128,
"f32" => F32,
"f64" => F64,
"char" => Char,
"bool" | "true" | "false" => Bool,
"str" | "&str" => Str,
// See #80181 for why these don't have symbols associated.
"slice" => Slice,
"array" => Array,
"tuple" => Tuple,
"unit" => Unit,
"pointer" | "*const" | "*mut" => RawPointer,
"reference" | "&" | "&mut" => Reference,
"fn" => Fn,
"never" | "!" => Never,
_ => return None,
};
debug!("resolved primitives {:?}", prim);
Some(Res::Primitive(prim))
}
fn strip_generics_from_path(path_str: &str) -> Result<String, ResolutionFailure<'static>> {
let mut stripped_segments = vec![];
let mut path = path_str.chars().peekable();
let mut segment = Vec::new();
while let Some(chr) = path.next() {
match chr {
':' => {
if path.next_if_eq(&':').is_some() {
let stripped_segment =
strip_generics_from_path_segment(mem::take(&mut segment))?;
if !stripped_segment.is_empty() {
stripped_segments.push(stripped_segment);
}
} else {
return Err(ResolutionFailure::MalformedGenerics(
MalformedGenerics::InvalidPathSeparator,
));
}
}
'<' => {
segment.push(chr);
match path.next() {
Some('<') => {
return Err(ResolutionFailure::MalformedGenerics(
MalformedGenerics::TooManyAngleBrackets,
));
}
Some('>') => {
return Err(ResolutionFailure::MalformedGenerics(
MalformedGenerics::EmptyAngleBrackets,
));
}
Some(chr) => {
segment.push(chr);
while let Some(chr) = path.next_if(|c| *c != '>') {
segment.push(chr);
}
}
None => break,
}
}
_ => segment.push(chr),
}
trace!("raw segment: {:?}", segment);
}
if !segment.is_empty() {
let stripped_segment = strip_generics_from_path_segment(segment)?;
if !stripped_segment.is_empty() {
stripped_segments.push(stripped_segment);
}
}
debug!("path_str: {:?}\nstripped segments: {:?}", path_str, &stripped_segments);
let stripped_path = stripped_segments.join("::");
if !stripped_path.is_empty() {
Ok(stripped_path)
} else {
Err(ResolutionFailure::MalformedGenerics(MalformedGenerics::MissingType))
}
}
fn strip_generics_from_path_segment(
segment: Vec<char>,
) -> Result<String, ResolutionFailure<'static>> {
let mut stripped_segment = String::new();
let mut param_depth = 0;
let mut latest_generics_chunk = String::new();
for c in segment {
if c == '<' {
param_depth += 1;
latest_generics_chunk.clear();
} else if c == '>' {
param_depth -= 1;
if latest_generics_chunk.contains(" as ") {
// The segment tries to use fully-qualified syntax, which is currently unsupported.
// Give a helpful error message instead of completely ignoring the angle brackets.
return Err(ResolutionFailure::MalformedGenerics(
MalformedGenerics::HasFullyQualifiedSyntax,
));
}
} else {
if param_depth == 0 {
stripped_segment.push(c);
} else {
latest_generics_chunk.push(c);
}
}
}
if param_depth == 0 {
Ok(stripped_segment)
} else {
// The segment has unbalanced angle brackets, e.g. `Vec<T` or `Vec<T>>`
Err(ResolutionFailure::MalformedGenerics(MalformedGenerics::UnbalancedAngleBrackets))
}
}