Google Git
Sign in
android / toolchain / rustc / d720b3f2ba07cb42ff7b311589c99daefe3aaa22 / . / src / librustdoc / passes / collect_intra_doc_links.rs
blob: 075951312a6393d738fab17772a2778f9b2085b9 [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 pulldown_cmark::LinkType;
use rustc_ast::util::comments::may_have_doc_links;
use rustc_data_structures::{
fx::{FxHashMap, FxHashSet},
intern::Interned,
};
use rustc_errors::{Applicability, Diagnostic};
use rustc_hir::def::Namespace::*;
use rustc_hir::def::{DefKind, Namespace, PerNS};
use rustc_hir::def_id::{DefId, CRATE_DEF_ID};
use rustc_hir::Mutability;
use rustc_middle::ty::{DefIdTree, Ty, TyCtxt};
use rustc_middle::{bug, ty};
use rustc_resolve::ParentScope;
use rustc_session::lint::Lint;
use rustc_span::hygiene::MacroKind;
use rustc_span::symbol::{sym, Ident, Symbol};
use rustc_span::BytePos;
use smallvec::{smallvec, SmallVec};
use std::borrow::Cow;
use std::mem;
use std::ops::Range;
use crate::clean::{self, utils::find_nearest_parent_module};
use crate::clean::{Crate, Item, ItemId, ItemLink, PrimitiveType};
use crate::core::DocContext;
use crate::html::markdown::{markdown_links, MarkdownLink};
use crate::lint::{BROKEN_INTRA_DOC_LINKS, PRIVATE_INTRA_DOC_LINKS};
use crate::passes::Pass;
use crate::visit::DocVisitor;
mod early;
pub(crate) use early::early_resolve_intra_doc_links;
pub(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 {
let mut collector =
LinkCollector { cx, mod_ids: Vec::new(), visited_links: FxHashMap::default() };
collector.visit_crate(&krate);
krate
}
#[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<'_>) -> Symbol {
match self {
Res::Def(_, id) => tcx.item_name(id),
Res::Primitive(prim) => prim.as_sym(),
}
}
fn def_id(self, tcx: TyCtxt<'_>) -> Option<DefId> {
match self {
Res::Def(_, id) => Some(id),
Res::Primitive(prim) => PrimitiveType::primitive_locations(tcx).get(&prim).copied(),
}
}
fn from_def_id(tcx: TyCtxt<'_>, def_id: DefId) -> Res {
Res::Def(tcx.def_kind(def_id), def_id)
}
/// Used for error reporting.
fn disambiguator_suggestion(self) -> Suggestion {
let kind = match self {
Res::Primitive(_) => return Suggestion::Prefix("prim"),
Res::Def(kind, _) => kind,
};
if kind == DefKind::Macro(MacroKind::Bang) {
return Suggestion::Macro;
} else if kind == DefKind::Fn || kind == DefKind::AssocFn {
return Suggestion::Function;
} else if kind == DefKind::Field {
return Suggestion::RemoveDisambiguator;
}
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)
}
}
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),
}
}
}
/// The link failed to resolve. [`resolution_failure`] should look to see if there's
/// a more helpful error that can be given.
#[derive(Debug)]
struct UnresolvedPath<'a> {
/// Item on which the link is resolved, used for resolving `Self`.
item_id: ItemId,
/// 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>,
}
#[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,
},
NotResolved(UnresolvedPath<'a>),
}
#[derive(Clone, Copy, 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,
}
#[derive(Clone, Debug, Hash, PartialEq, Eq)]
pub(crate) enum UrlFragment {
Item(DefId),
/// A part of a page that isn't a rust item.
///
/// Eg: `[Vector Examples](std::vec::Vec#examples)`
UserWritten(String),
}
impl UrlFragment {
/// Render the fragment, including the leading `#`.
pub(crate) fn render(&self, s: &mut String, tcx: TyCtxt<'_>) {
s.push('#');
match self {
&UrlFragment::Item(def_id) => {
let kind = match tcx.def_kind(def_id) {
DefKind::AssocFn => {
if tcx.impl_defaultness(def_id).has_value() {
"method."
} else {
"tymethod."
}
}
DefKind::AssocConst => "associatedconstant.",
DefKind::AssocTy => "associatedtype.",
DefKind::Variant => "variant.",
DefKind::Field => {
let parent_id = tcx.parent(def_id);
if tcx.def_kind(parent_id) == DefKind::Variant {
s.push_str("variant.");
s.push_str(tcx.item_name(parent_id).as_str());
".field."
} else {
"structfield."
}
}
kind => bug!("unexpected associated item kind: {:?}", kind),
};
s.push_str(kind);
s.push_str(tcx.item_name(def_id).as_str());
}
UrlFragment::UserWritten(raw) => s.push_str(&raw),
}
}
}
#[derive(Clone, Debug, Hash, PartialEq, Eq)]
struct ResolutionInfo {
item_id: ItemId,
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>,
}
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>,
/// 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<(Res, Option<UrlFragment>)>>,
}
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]: rustc_hir::VariantData::Struct
fn variant_field<'path>(
&self,
path_str: &'path str,
item_id: ItemId,
module_id: DefId,
) -> Result<(Res, DefId), UnresolvedPath<'path>> {
let tcx = self.cx.tcx;
let no_res = || UnresolvedPath {
item_id,
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_name = split
.next()
.map(|f| Symbol::intern(f))
.expect("fold_item should ensure link is non-empty");
let 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| 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.resolve_path(&path, TypeNS, item_id, module_id).ok_or_else(no_res)?;
match ty_res {
Res::Def(DefKind::Enum, did) => match tcx.type_of(did).kind() {
ty::Adt(def, _) if def.is_enum() => {
if let Some(field) = def.all_fields().find(|f| f.name == variant_field_name) {
Ok((ty_res, field.did))
} else {
Err(UnresolvedPath {
item_id,
module_id,
partial_res: Some(Res::Def(DefKind::Enum, def.did())),
unresolved: variant_field_name.to_string().into(),
})
}
}
_ => unreachable!(),
},
_ => Err(UnresolvedPath {
item_id,
module_id,
partial_res: Some(ty_res),
unresolved: variant_name.to_string().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, DefId)> {
let tcx = self.cx.tcx;
prim_ty.impls(tcx).find_map(|impl_| {
tcx.associated_items(impl_)
.find_by_name_and_namespace(tcx, Ident::with_dummy_span(item_name), ns, impl_)
.map(|item| (Res::Primitive(prim_ty), item.def_id))
})
}
fn resolve_self_ty(&self, path_str: &str, ns: Namespace, item_id: ItemId) -> Option<Res> {
if ns != TypeNS || path_str != "Self" {
return None;
}
let tcx = self.cx.tcx;
item_id
.as_def_id()
.map(|def_id| match tcx.def_kind(def_id) {
def_kind @ (DefKind::AssocFn
| DefKind::AssocConst
| DefKind::AssocTy
| DefKind::Variant
| DefKind::Field) => {
let parent_def_id = tcx.parent(def_id);
if def_kind == DefKind::Field && tcx.def_kind(parent_def_id) == DefKind::Variant
{
tcx.parent(parent_def_id)
} else {
parent_def_id
}
}
_ => def_id,
})
.and_then(|self_id| match tcx.def_kind(self_id) {
DefKind::Impl => self.def_id_to_res(self_id),
DefKind::Use => None,
def_kind => Some(Res::Def(def_kind, self_id)),
})
}
/// Convenience wrapper around `resolve_rustdoc_path`.
///
/// This also handles resolving `true` and `false` as booleans.
/// NOTE: `resolve_rustdoc_path` 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,
item_id: ItemId,
module_id: DefId,
) -> Option<Res> {
if let res @ Some(..) = self.resolve_self_ty(path_str, ns, item_id) {
return res;
}
// Resolver doesn't know about true, false, and types that aren't paths (e.g. `()`).
let result = self
.cx
.resolver_caches
.doc_link_resolutions
.get(&(Symbol::intern(path_str), ns, module_id))
.copied()
.unwrap_or_else(|| {
self.cx.enter_resolver(|resolver| {
let parent_scope =
ParentScope::module(resolver.expect_module(module_id), resolver);
resolver.resolve_rustdoc_path(path_str, ns, parent_scope)
})
})
.and_then(|res| res.try_into().ok())
.or_else(|| resolve_primitive(path_str, ns));
debug!("{} resolved to {:?} in namespace {:?}", path_str, result, ns);
result
}
/// 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,
item_id: ItemId,
module_id: DefId,
) -> Result<(Res, Option<DefId>), UnresolvedPath<'path>> {
if let Some(res) = self.resolve_path(path_str, ns, item_id, module_id) {
return Ok(match res {
Res::Def(
DefKind::AssocFn | DefKind::AssocConst | DefKind::AssocTy | DefKind::Variant,
def_id,
) => (Res::from_def_id(self.cx.tcx, self.cx.tcx.parent(def_id)), Some(def_id)),
_ => (res, None),
});
} else if ns == MacroNS {
return Err(UnresolvedPath {
item_id,
module_id,
partial_res: None,
unresolved: path_str.into(),
});
}
// 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 `::`, assuming {} was correctly not in scope", item_name);
UnresolvedPath {
item_id,
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, item_id, module_id))
.and_then(|ty_res| {
self.resolve_associated_item(ty_res, item_name, ns, module_id).map(Ok)
})
.unwrap_or_else(|| {
if ns == Namespace::ValueNS {
self.variant_field(path_str, item_id, module_id)
} else {
Err(UnresolvedPath {
item_id,
module_id,
partial_res: None,
unresolved: path_root.into(),
})
}
})
.map(|(res, def_id)| (res, Some(def_id)))
}
/// Convert a DefId to a Res, where possible.
///
/// This is used for resolving type aliases.
fn def_id_to_res(&self, ty_id: DefId) -> Option<Res> {
use PrimitiveType::*;
Some(match *self.cx.tcx.type_of(ty_id).kind() {
ty::Bool => Res::Primitive(Bool),
ty::Char => Res::Primitive(Char),
ty::Int(ity) => Res::Primitive(ity.into()),
ty::Uint(uty) => Res::Primitive(uty.into()),
ty::Float(fty) => Res::Primitive(fty.into()),
ty::Str => Res::Primitive(Str),
ty::Tuple(tys) if tys.is_empty() => Res::Primitive(Unit),
ty::Tuple(_) => Res::Primitive(Tuple),
ty::Array(..) => Res::Primitive(Array),
ty::Slice(_) => Res::Primitive(Slice),
ty::RawPtr(_) => Res::Primitive(RawPointer),
ty::Ref(..) => Res::Primitive(Reference),
ty::FnDef(..) => panic!("type alias to a function definition"),
ty::FnPtr(_) => Res::Primitive(Fn),
ty::Never => Res::Primitive(Never),
ty::Adt(ty::AdtDef(Interned(&ty::AdtDefData { did, .. }, _)), _) | ty::Foreign(did) => {
Res::from_def_id(self.cx.tcx, did)
}
ty::Alias(..)
| ty::Closure(..)
| ty::Generator(..)
| ty::GeneratorWitness(_)
| ty::Dynamic(..)
| ty::Param(_)
| ty::Bound(..)
| ty::Placeholder(_)
| ty::Infer(_)
| ty::Error(_) => return None,
})
}
/// Convert a PrimitiveType to a Ty, where possible.
///
/// This is used for resolving trait impls for primitives
fn primitive_type_to_ty(&mut self, prim: PrimitiveType) -> Option<Ty<'tcx>> {
use PrimitiveType::*;
let tcx = self.cx.tcx;
// FIXME: Only simple types are supported here, see if we can support
// other types such as Tuple, Array, Slice, etc.
// See https://github.com/rust-lang/rust/issues/90703#issuecomment-1004263455
Some(tcx.mk_ty(match prim {
Bool => ty::Bool,
Str => ty::Str,
Char => ty::Char,
Never => ty::Never,
I8 => ty::Int(ty::IntTy::I8),
I16 => ty::Int(ty::IntTy::I16),
I32 => ty::Int(ty::IntTy::I32),
I64 => ty::Int(ty::IntTy::I64),
I128 => ty::Int(ty::IntTy::I128),
Isize => ty::Int(ty::IntTy::Isize),
F32 => ty::Float(ty::FloatTy::F32),
F64 => ty::Float(ty::FloatTy::F64),
U8 => ty::Uint(ty::UintTy::U8),
U16 => ty::Uint(ty::UintTy::U16),
U32 => ty::Uint(ty::UintTy::U32),
U64 => ty::Uint(ty::UintTy::U64),
U128 => ty::Uint(ty::UintTy::U128),
Usize => ty::Uint(ty::UintTy::Usize),
_ => return None,
}))
}
/// Resolve an associated item, returning its containing page's `Res`
/// and the fragment targeting the associated item on its page.
fn resolve_associated_item(
&mut self,
root_res: Res,
item_name: Symbol,
ns: Namespace,
module_id: DefId,
) -> Option<(Res, DefId)> {
let tcx = self.cx.tcx;
match root_res {
Res::Primitive(prim) => {
self.resolve_primitive_associated_item(prim, ns, item_name).or_else(|| {
self.primitive_type_to_ty(prim)
.and_then(|ty| {
resolve_associated_trait_item(ty, module_id, item_name, ns, self.cx)
})
.map(|item| (root_res, item.def_id))
})
}
Res::Def(DefKind::TyAlias, did) => {
// Resolve the link on the type the alias points to.
// FIXME: if the associated item is defined directly on the type alias,
// it will show up on its documentation page, we should link there instead.
let res = self.def_id_to_res(did)?;
self.resolve_associated_item(res, item_name, ns, module_id)
}
Res::Def(
def_kind @ (DefKind::Struct | DefKind::Union | DefKind::Enum | DefKind::ForeignTy),
did,
) => {
debug!("looking for associated item named {} for item {:?}", item_name, did);
// Checks if item_name is a variant of the `SomeItem` enum
if ns == TypeNS && def_kind == DefKind::Enum {
match tcx.type_of(did).kind() {
ty::Adt(adt_def, _) => {
for variant in adt_def.variants() {
if variant.name == item_name {
return Some((root_res, variant.def_id));
}
}
}
_ => unreachable!(),
}
}
// 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,
)
})
.copied()
// 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(|| {
resolve_associated_trait_item(
tcx.type_of(did),
module_id,
item_name,
ns,
self.cx,
)
});
debug!("got associated item {:?}", assoc_item);
if let Some(item) = assoc_item {
return Some((root_res, item.def_id));
}
if ns != Namespace::ValueNS {
return None;
}
debug!("looking for 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 only resolves struct fields,
// not variant fields (2 path segments, not 3).
//
// We need to handle struct (and union) fields in this code because
// syntactically their paths are identical to associated item paths:
// `module::Type::field` and `module::Type::Assoc`.
//
// On the other hand, variant fields can't be mistaken for associated
// items because they look like this: `module::Type::Variant::field`.
//
// Variants themselves don't need to be handled here, even though
// they also look like associated items (`module::Type::Variant`),
// because they are real Rust syntax (unlike the intra-doc links
// field syntax) and are handled by the compiler's resolver.
let def = match tcx.type_of(did).kind() {
ty::Adt(def, _) if !def.is_enum() => def,
_ => return None,
};
let field =
def.non_enum_variant().fields.iter().find(|item| item.name == item_name)?;
Some((root_res, 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 res = Res::Def(item.kind.as_def_kind(), item.def_id);
(res, item.def_id)
}),
_ => None,
}
}
}
fn full_res(tcx: TyCtxt<'_>, (base, assoc_item): (Res, Option<DefId>)) -> Res {
assoc_item.map_or(base, |def_id| Res::from_def_id(tcx, def_id))
}
/// 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<'a>(
ty: Ty<'a>,
module: DefId,
item_name: Symbol,
ns: Namespace,
cx: &mut DocContext<'a>,
) -> Option<ty::AssocItem> {
// 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 = trait_impls_for(cx, ty, module);
debug!("considering traits {:?}", traits);
let mut candidates = traits.iter().filter_map(|&(impl_, trait_)| {
cx.tcx
.associated_items(trait_)
.find_by_name_and_namespace(cx.tcx, Ident::with_dummy_span(item_name), ns, trait_)
.map(|trait_assoc| {
trait_assoc_to_impl_assoc_item(cx.tcx, impl_, trait_assoc.def_id)
.unwrap_or(trait_assoc)
})
});
// FIXME(#74563): warn about ambiguity
debug!("the candidates were {:?}", candidates.clone().collect::<Vec<_>>());
candidates.next().copied()
}
/// Find the associated item in the impl `impl_id` that corresponds to the
/// trait associated item `trait_assoc_id`.
///
/// This function returns `None` if no associated item was found in the impl.
/// This can occur when the trait associated item has a default value that is
/// not overridden in the impl.
///
/// This is just a wrapper around [`TyCtxt::impl_item_implementor_ids()`] and
/// [`TyCtxt::associated_item()`] (with some helpful logging added).
#[instrument(level = "debug", skip(tcx), ret)]
fn trait_assoc_to_impl_assoc_item<'tcx>(
tcx: TyCtxt<'tcx>,
impl_id: DefId,
trait_assoc_id: DefId,
) -> Option<&'tcx ty::AssocItem> {
let trait_to_impl_assoc_map = tcx.impl_item_implementor_ids(impl_id);
debug!(?trait_to_impl_assoc_map);
let impl_assoc_id = *trait_to_impl_assoc_map.get(&trait_assoc_id)?;
debug!(?impl_assoc_id);
Some(tcx.associated_item(impl_assoc_id))
}
/// Given a type, return all trait impls in scope in `module` for that type.
/// Returns a set of pairs of `(impl_id, trait_id)`.
///
/// 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.
#[instrument(level = "debug", skip(cx))]
fn trait_impls_for<'a>(
cx: &mut DocContext<'a>,
ty: Ty<'a>,
module: DefId,
) -> FxHashSet<(DefId, DefId)> {
let tcx = cx.tcx;
let iter = cx.resolver_caches.traits_in_scope[&module].iter().flat_map(|trait_candidate| {
let trait_ = trait_candidate.def_id;
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.skip_binder().self_ty();
trace!(
"comparing type {} with kind {:?} against type {:?}",
impl_type,
impl_type.kind(),
ty
);
// Fast path: if this is a primitive simple `==` will work
// NOTE: the `match` is necessary; see #92662.
// this allows us to ignore generics because the user input
// may not include the generic placeholders
// e.g. this allows us to match Foo (user comment) with Foo<T> (actual type)
let saw_impl = impl_type == ty
|| match (impl_type.kind(), ty.kind()) {
(ty::Adt(impl_def, _), ty::Adt(ty_def, _)) => {
debug!("impl def_id: {:?}, ty def_id: {:?}", impl_def.did(), ty_def.did());
impl_def.did() == ty_def.did()
}
_ => false,
};
if saw_impl { Some((impl_, 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> DocVisitor for LinkCollector<'a, 'tcx> {
fn visit_item(&mut self, item: &Item) {
let parent_node =
item.item_id.as_def_id().and_then(|did| find_nearest_parent_module(self.cx.tcx, did));
if parent_node.is_some() {
trace!("got parent node for {:?} {:?}, id {:?}", item.type_(), item.name, item.item_id);
}
let inner_docs = item.inner_docs(self.cx.tcx);
if item.is_mod() && inner_docs {
self.mod_ids.push(item.item_id.expect_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.prepare_to_doc_link_resolution() {
if !may_have_doc_links(&doc) {
continue;
}
debug!("combined_docs={}", doc);
// 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.
let parent_node = parent_module.or(parent_node);
let mut tmp_links = self
.cx
.resolver_caches
.markdown_links
.take()
.expect("`markdown_links` are already borrowed");
if !tmp_links.contains_key(&doc) {
tmp_links.insert(doc.clone(), preprocessed_markdown_links(&doc));
}
for md_link in &tmp_links[&doc] {
let link = self.resolve_link(item, &doc, parent_node, md_link);
if let Some(link) = link {
self.cx.cache.intra_doc_links.entry(item.item_id).or_default().push(link);
}
}
self.cx.resolver_caches.markdown_links = Some(tmp_links);
}
if item.is_mod() {
if !inner_docs {
self.mod_ids.push(item.item_id.expect_def_id());
}
self.visit_item_recur(item);
self.mod_ids.pop();
} else {
self.visit_item_recur(item)
}
}
}
enum PreprocessingError {
/// User error: `[std#x#y]` is not valid
MultipleAnchors,
Disambiguator(Range<usize>, String),
MalformedGenerics(MalformedGenerics, String),
}
impl PreprocessingError {
fn report(&self, cx: &DocContext<'_>, diag_info: DiagnosticInfo<'_>) {
match self {
PreprocessingError::MultipleAnchors => report_multiple_anchors(cx, diag_info),
PreprocessingError::Disambiguator(range, msg) => {
disambiguator_error(cx, diag_info, range.clone(), msg)
}
PreprocessingError::MalformedGenerics(err, path_str) => {
report_malformed_generics(cx, diag_info, *err, path_str)
}
}
}
}
#[derive(Clone)]
struct PreprocessingInfo {
path_str: String,
disambiguator: Option<Disambiguator>,
extra_fragment: Option<String>,
link_text: String,
}
// Not a typedef to avoid leaking several private structures from this module.
pub(crate) struct PreprocessedMarkdownLink(
Result<PreprocessingInfo, PreprocessingError>,
MarkdownLink,
);
/// 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(
ori_link: &MarkdownLink,
) -> Option<Result<PreprocessingInfo, PreprocessingError>> {
// [] 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(PreprocessingError::MultipleAnchors));
}
// Parse and strip the disambiguator from the link, if present.
let (disambiguator, path_str, link_text) = match Disambiguator::from_str(link) {
Ok(Some((d, path, link_text))) => (Some(d), path.trim(), link_text.trim()),
Ok(None) => (None, link.trim(), link.trim()),
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;
}
// 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) => {
debug!("link has malformed generics: {}", path_str);
return Some(Err(PreprocessingError::MalformedGenerics(err, path_str.to_owned())));
}
}
} 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(|frag| frag.to_owned()),
link_text: link_text.to_owned(),
}))
}
fn preprocessed_markdown_links(s: &str) -> Vec<PreprocessedMarkdownLink> {
markdown_links(s, |link| {
preprocess_link(&link).map(|pp_link| PreprocessedMarkdownLink(pp_link, link))
})
}
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,
parent_node: Option<DefId>,
link: &PreprocessedMarkdownLink,
) -> Option<ItemLink> {
let PreprocessedMarkdownLink(pp_link, ori_link) = link;
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 } =
pp_link.as_ref().map_err(|err| err.report(self.cx, diag_info.clone())).ok()?;
let disambiguator = *disambiguator;
// 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 inner_docs = item.inner_docs(self.cx.tcx);
let base_node =
if item.is_mod() && inner_docs { self.mod_ids.last().copied() } else { parent_node };
let module_id = base_node.expect("doc link without parent module");
let (mut res, fragment) = self.resolve_with_disambiguator_cached(
ResolutionInfo {
item_id: item.item_id,
module_id,
dis: disambiguator,
path_str: path_str.to_owned(),
extra_fragment: extra_fragment.clone(),
},
diag_info.clone(), // this struct should really be Copy, but Range is not :(
// For reference-style links we want to report only one error so unsuccessful
// resolutions are cached, for other links we want to report an error every
// time so they are not cached.
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)) {
res = prim;
} 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;
}
}
}
match res {
Res::Primitive(prim) => {
if let Some(UrlFragment::Item(id)) = fragment {
// 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.
let kind = self.cx.tcx.def_kind(id);
self.verify_disambiguator(
path_str,
ori_link,
kind,
id,
disambiguator,
item,
&diag_info,
)?;
// 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.item_id.is_local()
&& !self.cx.tcx.features().intra_doc_pointers
{
self.report_rawptr_assoc_feature_gate(dox, ori_link, item);
}
} else {
match disambiguator {
Some(Disambiguator::Primitive | Disambiguator::Namespace(_)) | None => {}
Some(other) => {
self.report_disambiguator_mismatch(
path_str, ori_link, other, res, &diag_info,
);
return None;
}
}
}
res.def_id(self.cx.tcx).map(|page_id| ItemLink {
link: ori_link.link.clone(),
link_text: link_text.clone(),
page_id,
fragment,
})
}
Res::Def(kind, id) => {
let (kind_for_dis, id_for_dis) = if let Some(UrlFragment::Item(id)) = fragment {
(self.cx.tcx.def_kind(id), id)
} else {
(kind, id)
};
self.verify_disambiguator(
path_str,
ori_link,
kind_for_dis,
id_for_dis,
disambiguator,
item,
&diag_info,
)?;
let page_id = clean::register_res(self.cx, rustc_hir::def::Res::Def(kind, id));
Some(ItemLink {
link: ori_link.link.clone(),
link_text: link_text.clone(),
page_id,
fragment,
})
}
}
}
fn verify_disambiguator(
&self,
path_str: &str,
ori_link: &MarkdownLink,
kind: DefKind,
id: DefId,
disambiguator: Option<Disambiguator>,
item: &Item,
diag_info: &DiagnosticInfo<'_>,
) -> Option<()> {
debug!("intra-doc link to {} resolved to {:?}", path_str, (kind, 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)) => {
self.report_disambiguator_mismatch(path_str,ori_link,specified, Res::Def(kind, id),diag_info);
return None;
}
}
// item can be non-local e.g. when using #[doc(primitive = "pointer")]
if let Some((src_id, dst_id)) = id
.as_local()
// The `expect_def_id()` should be okay because `local_def_id_to_hir_id`
// would presumably panic if a fake `DefIndex` were passed.
.and_then(|dst_id| {
item.item_id.expect_def_id().as_local().map(|src_id| (src_id, dst_id))
})
{
if self.cx.tcx.effective_visibilities(()).is_exported(src_id)
&& !self.cx.tcx.effective_visibilities(()).is_exported(dst_id)
{
privacy_error(self.cx, diag_info, path_str);
}
}
Some(())
}
fn report_disambiguator_mismatch(
&self,
path_str: &str,
ori_link: &MarkdownLink,
specified: Disambiguator,
resolved: Res,
diag_info: &DiagnosticInfo<'_>,
) {
// 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 Diagnostic, sp: Option<rustc_span::Span>| {
let note = format!(
"this link resolved to {} {}, which is not {} {}",
resolved.article(),
resolved.descr(),
specified.article(),
specified.descr(),
);
if let Some(sp) = sp {
diag.span_label(sp, &note);
} else {
diag.note(&note);
}
suggest_disambiguator(resolved, diag, path_str, &ori_link.link, sp);
};
report_diagnostic(self.cx.tcx, BROKEN_INTRA_DOC_LINKS, &msg, diag_info, callback);
}
fn report_rawptr_assoc_feature_gate(&self, dox: &str, ori_link: &MarkdownLink, item: &Item) {
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();
}
fn resolve_with_disambiguator_cached(
&mut self,
key: ResolutionInfo,
diag: DiagnosticInfo<'_>,
// If errors are cached then they are only reported on first occurrence
// which we want in some cases but not in others.
cache_errors: bool,
) -> Option<(Res, Option<UrlFragment>)> {
if let Some(res) = self.visited_links.get(&key) {
if res.is_some() || cache_errors {
return res.clone();
}
}
let res = self.resolve_with_disambiguator(&key, diag.clone()).and_then(|(res, def_id)| {
let fragment = match (&key.extra_fragment, def_id) {
(Some(_), Some(def_id)) => {
report_anchor_conflict(self.cx, diag, def_id);
return None;
}
(Some(u_frag), None) => Some(UrlFragment::UserWritten(u_frag.clone())),
(None, Some(def_id)) => Some(UrlFragment::Item(def_id)),
(None, None) => None,
};
Some((res, fragment))
});
if res.is_some() || cache_errors {
self.visited_links.insert(key, res.clone());
}
res
}
/// 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<DefId>)> {
let disambiguator = key.dis;
let path_str = &key.path_str;
let item_id = key.item_id;
let base_node = key.module_id;
match disambiguator.map(Disambiguator::ns) {
Some(expected_ns) => {
match self.resolve(path_str, expected_ns, item_id, base_node) {
Ok(res) => Some(res),
Err(err) => {
// We only looked in one namespace. Try to give a better error if possible.
// 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.
let mut err = ResolutionFailure::NotResolved(err);
for other_ns in [TypeNS, ValueNS, MacroNS] {
if other_ns != expected_ns {
if let Ok(res) =
self.resolve(path_str, other_ns, item_id, base_node)
{
err = ResolutionFailure::WrongNamespace {
res: full_res(self.cx.tcx, res),
expected_ns,
};
break;
}
}
}
resolution_failure(self, diag, path_str, disambiguator, smallvec![err])
}
}
}
None => {
// Try everything!
let mut candidate = |ns| {
self.resolve(path_str, ns, item_id, base_node)
.map_err(ResolutionFailure::NotResolved)
};
let candidates = PerNS {
macro_ns: candidate(MacroNS),
type_ns: candidate(TypeNS),
value_ns: candidate(ValueNS).and_then(|(res, def_id)| {
match res {
// Constructors are picked up in the type namespace.
Res::Def(DefKind::Ctor(..), _) => {
Err(ResolutionFailure::WrongNamespace { res, expected_ns: TypeNS })
}
_ => Ok((res, def_id)),
}
}),
};
let len = candidates.iter().filter(|res| res.is_ok()).count();
if len == 0 {
return resolution_failure(
self,
diag,
path_str,
disambiguator,
candidates.into_iter().filter_map(|res| res.err()).collect(),
);
}
if len == 1 {
Some(candidates.into_iter().find_map(|res| res.ok()).unwrap())
} else if len == 2 && is_derive_trait_collision(&candidates) {
Some(candidates.type_ns.unwrap())
} else {
let ignore_macro = is_derive_trait_collision(&candidates);
// If we're reporting an ambiguity, don't mention the namespaces that failed
let mut candidates =
candidates.map(|candidate| candidate.ok().map(|(res, _)| res));
if ignore_macro {
candidates.macro_ns = None;
}
ambiguity_error(self.cx, diag, path_str, candidates.present_items().collect());
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 {
/// Given a link, parse and return `(disambiguator, path_str, link_text)`.
///
/// 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, &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(Mutability::Not)),
"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..], &rest[1..])))
} else {
let suffixes = [
("!()", DefKind::Macro(MacroKind::Bang)),
("!{}", DefKind::Macro(MacroKind::Bang)),
("![]", DefKind::Macro(MacroKind::Bang)),
("()", DefKind::Fn),
("!", DefKind::Macro(MacroKind::Bang)),
];
for (suffix, kind) in suffixes {
if let Some(path_str) = link.strip_suffix(suffix) {
// Avoid turning `!` or `()` into an empty string
if !path_str.is_empty() {
return Ok(Some((Kind(kind), path_str, link)));
}
}
}
Ok(None)
}
}
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): the source of `DefKind::descr` only uses the DefId for
// printing "module" vs "crate" so using the wrong ID is not a huge problem
Self::Kind(k) => k.descr(CRATE_DEF_ID.to_def_id()),
Self::Primitive => "builtin type",
}
}
}
/// A suggestion to show in a diagnostic.
enum Suggestion {
/// `struct@`
Prefix(&'static str),
/// `f()`
Function,
/// `m!`
Macro,
/// `foo` without any disambiguator
RemoveDisambiguator,
}
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(),
Self::RemoveDisambiguator => "remove the disambiguator".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),
Self::RemoveDisambiguator => path_str.into(),
}
}
fn as_help_span(
&self,
path_str: &str,
ori_link: &str,
sp: rustc_span::Span,
) -> Vec<(rustc_span::Span, String)> {
let inner_sp = match ori_link.find('(') {
Some(index) => sp.with_hi(sp.lo() + BytePos(index as _)),
None => sp,
};
let inner_sp = match ori_link.find('!') {
Some(index) => inner_sp.with_hi(inner_sp.lo() + BytePos(index as _)),
None => inner_sp,
};
let inner_sp = match ori_link.find('@') {
Some(index) => inner_sp.with_lo(inner_sp.lo() + BytePos(index as u32 + 1)),
None => inner_sp,
};
match self {
Self::Prefix(prefix) => {
// FIXME: if this is an implied shortcut link, it's bad style to suggest `@`
let mut sugg = vec![(sp.with_hi(inner_sp.lo()), format!("{}@", prefix))];
if sp.hi() != inner_sp.hi() {
sugg.push((inner_sp.shrink_to_hi().with_hi(sp.hi()), String::new()));
}
sugg
}
Self::Function => {
let mut sugg = vec![(inner_sp.shrink_to_hi().with_hi(sp.hi()), "()".to_string())];
if sp.lo() != inner_sp.lo() {
sugg.push((inner_sp.shrink_to_lo().with_lo(sp.lo()), String::new()));
}
sugg
}
Self::Macro => {
let mut sugg = vec![(inner_sp.shrink_to_hi(), "!".to_string())];
if sp.lo() != inner_sp.lo() {
sugg.push((inner_sp.shrink_to_lo().with_lo(sp.lo()), String::new()));
}
sugg
}
Self::RemoveDisambiguator => vec![(sp, path_str.into())],
}
}
}
/// 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 Diagnostic, Option<rustc_span::Span>),
) {
let Some(hir_id) = DocContext::as_local_hir_id(tcx, item.item_id)
else {
// 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, msg, |lint| {
let span =
super::source_span_for_markdown_range(tcx, dox, link_range, &item.attrs).map(|sp| {
if dox.as_bytes().get(link_range.start) == Some(&b'`')
&& dox.as_bytes().get(link_range.end - 1) == Some(&b'`')
{
sp.with_lo(sp.lo() + BytePos(1)).with_hi(sp.hi() - BytePos(1))
} else {
sp
}
});
if let Some(sp) = span {
lint.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.
lint.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(lint, span);
lint
});
}
/// 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]>,
) -> Option<(Res, Option<DefId>)> {
let tcx = collector.cx.tcx;
let mut recovered_res = None;
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(UnresolvedPath {
item_id,
module_id,
partial_res,
unresolved,
}) = &mut failure
{
use DefKind::*;
let item_id = *item_id;
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 Some((start, end)) = split(name) 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 Ok(res) = collector.resolve(start, ns, item_id, module_id) {
debug!("found partial_res={:?}", res);
*partial_res = Some(full_res(collector.cx.tcx, 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 !path_str.contains("::") {
if disambiguator.map_or(true, |d| d.ns() == MacroNS)
&& let Some(&res) = collector.cx.resolver_caches.all_macro_rules
.get(&Symbol::intern(path_str))
{
diag.note(format!(
"`macro_rules` named `{path_str}` exists in this crate, \
but it is not in scope at this link's location"
));
recovered_res = res.try_into().ok().map(|res| (res, None));
} else {
// If the link has `::` in it, assume it was meant to be an
// intra-doc link. Otherwise, the `[]` might be unrelated.
diag.help("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 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
| InlineConst => {
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 | ImplTraitPlaceholder
| TraitAlias | TyParam | Static(_) => "associated item",
Impl | GlobalAsm => unreachable!("not a path"),
}
} else {
"associated item"
};
let name = res.name(tcx);
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::WrongNamespace { res, expected_ns } => {
suggest_disambiguator(res, diag, path_str, diag_info.ori_link, sp);
format!(
"this link resolves to {}, which is not in the {} namespace",
item(res),
expected_ns.descr()
)
}
};
if let Some(span) = sp {
diag.span_label(span, &note);
} else {
diag.note(&note);
}
}
},
);
recovered_res
}
fn report_multiple_anchors(cx: &DocContext<'_>, diag_info: DiagnosticInfo<'_>) {
let msg = format!("`{}` contains multiple anchors", diag_info.ori_link);
anchor_failure(cx, diag_info, &msg, 1)
}
fn report_anchor_conflict(cx: &DocContext<'_>, diag_info: DiagnosticInfo<'_>, def_id: DefId) {
let (link, kind) = (diag_info.ori_link, Res::from_def_id(cx.tcx, def_id).descr());
let msg = format!("`{link}` contains an anchor, but links to {kind}s are already anchored");
anchor_failure(cx, diag_info, &msg, 0)
}
/// Report an anchor failure.
fn anchor_failure(
cx: &DocContext<'_>,
diag_info: DiagnosticInfo<'_>,
msg: &str,
anchor_idx: usize,
) {
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() + BytePos(fragment_offset as _));
}
diag.span_label(sp, "invalid anchor");
}
});
}
/// 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| {
let msg = format!(
"see {}/rustdoc/write-documentation/linking-to-items-by-name.html#namespaces-and-disambiguators for more info about disambiguators",
crate::DOC_RUST_LANG_ORG_CHANNEL
);
diag.note(&msg);
});
}
fn report_malformed_generics(
cx: &DocContext<'_>,
diag_info: DiagnosticInfo<'_>,
err: MalformedGenerics,
path_str: &str,
) {
report_diagnostic(
cx.tcx,
BROKEN_INTRA_DOC_LINKS,
&format!("unresolved link to `{}`", path_str),
&diag_info,
|diag, sp| {
let note = match err {
MalformedGenerics::UnbalancedAngleBrackets => "unbalanced angle brackets",
MalformedGenerics::MissingType => "missing type for generic parameters",
MalformedGenerics::HasFullyQualifiedSyntax => {
diag.note(
"see https://github.com/rust-lang/rust/issues/74563 for more information",
);
"fully-qualified syntax is unsupported"
}
MalformedGenerics::InvalidPathSeparator => "has invalid path separator",
MalformedGenerics::TooManyAngleBrackets => "too many angle brackets",
MalformedGenerics::EmptyAngleBrackets => "empty angle brackets",
};
if let Some(span) = sp {
diag.span_label(span, note);
} else {
diag.note(note);
}
},
);
}
/// 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 {
suggest_disambiguator(res, diag, path_str, diag_info.ori_link, sp);
}
});
}
/// In case of an ambiguity or mismatched disambiguator, suggest the correct
/// disambiguator.
fn suggest_disambiguator(
res: Res,
diag: &mut Diagnostic,
path_str: &str,
ori_link: &str,
sp: Option<rustc_span::Span>,
) {
let suggestion = res.disambiguator_suggestion();
let help = format!("to link to the {}, {}", res.descr(), suggestion.descr());
if let Some(sp) = sp {
let mut spans = suggestion.as_help_span(path_str, ori_link, sp);
if spans.len() > 1 {
diag.multipart_suggestion(&help, spans, Applicability::MaybeIncorrect);
} else {
let (sp, suggestion_text) = spans.pop().unwrap();
diag.span_suggestion_verbose(sp, &help, suggestion_text, 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;
sym.as_str()
}
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);
});
}
/// 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, MalformedGenerics> {
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(MalformedGenerics::InvalidPathSeparator);
}
}
'<' => {
segment.push(chr);
match path.next() {
Some('<') => {
return Err(MalformedGenerics::TooManyAngleBrackets);
}
Some('>') => {
return Err(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(MalformedGenerics::MissingType) }
}
fn strip_generics_from_path_segment(segment: Vec<char>) -> Result<String, MalformedGenerics> {
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(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(MalformedGenerics::UnbalancedAngleBrackets)
}
}