1 use crate::clean::auto_trait::AutoTraitFinder;
2 use crate::clean::blanket_impl::BlanketImplFinder;
3 use crate::clean::render_macro_matchers::render_macro_matcher;
5 inline, Clean, Crate, ExternalCrate, Generic, GenericArg, GenericArgs, ImportSource, Item,
6 ItemKind, Lifetime, Path, PathSegment, Primitive, PrimitiveType, Type, TypeBinding, Visibility,
8 use crate::core::DocContext;
9 use crate::formats::item_type::ItemType;
10 use crate::visit_lib::LibEmbargoVisitor;
13 use rustc_ast::tokenstream::TokenTree;
14 use rustc_data_structures::thin_vec::ThinVec;
16 use rustc_hir::def::{DefKind, Res};
17 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
18 use rustc_middle::mir;
19 use rustc_middle::mir::interpret::ConstValue;
20 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
21 use rustc_middle::ty::{self, DefIdTree, TyCtxt};
22 use rustc_span::symbol::{kw, sym, Symbol};
23 use std::fmt::Write as _;
29 pub(crate) fn krate(cx: &mut DocContext<'_>) -> Crate {
30 let module = crate::visit_ast::RustdocVisitor::new(cx).visit();
32 for &cnum in cx.tcx.crates(()) {
33 // Analyze doc-reachability for extern items
34 LibEmbargoVisitor::new(cx).visit_lib(cnum);
37 // Clean the crate, translating the entire librustc_ast AST to one that is
38 // understood by rustdoc.
39 let mut module = module.clean(cx);
42 ItemKind::ModuleItem(ref module) => {
43 for it in &module.items {
44 // `compiler_builtins` should be masked too, but we can't apply
45 // `#[doc(masked)]` to the injected `extern crate` because it's unstable.
46 if it.is_extern_crate()
47 && (it.attrs.has_doc_flag(sym::masked)
48 || cx.tcx.is_compiler_builtins(it.item_id.krate()))
50 cx.cache.masked_crates.insert(it.item_id.krate());
57 let local_crate = ExternalCrate { crate_num: LOCAL_CRATE };
58 let primitives = local_crate.primitives(cx.tcx);
59 let keywords = local_crate.keywords(cx.tcx);
61 let ItemKind::ModuleItem(ref mut m) = *module.kind
62 else { unreachable!() };
63 m.items.extend(primitives.iter().map(|&(def_id, prim)| {
64 Item::from_def_id_and_parts(
67 ItemKind::PrimitiveItem(prim),
71 m.items.extend(keywords.into_iter().map(|(def_id, kw)| {
72 Item::from_def_id_and_parts(def_id, Some(kw), ItemKind::KeywordItem(kw), cx)
76 Crate { module, primitives, external_traits: cx.external_traits.clone() }
79 pub(crate) fn substs_to_args<'tcx>(
80 cx: &mut DocContext<'tcx>,
81 substs: &[ty::subst::GenericArg<'tcx>],
83 ) -> Vec<GenericArg> {
85 Vec::with_capacity(substs.len().saturating_sub(if skip_first { 1 } else { 0 }));
86 ret_val.extend(substs.iter().filter_map(|kind| match kind.unpack() {
87 GenericArgKind::Lifetime(lt) => {
88 Some(GenericArg::Lifetime(lt.clean(cx).unwrap_or(Lifetime::elided())))
90 GenericArgKind::Type(_) if skip_first => {
94 GenericArgKind::Type(ty) => Some(GenericArg::Type(ty.clean(cx))),
95 GenericArgKind::Const(ct) => Some(GenericArg::Const(Box::new(ct.clean(cx)))),
100 fn external_generic_args<'tcx>(
101 cx: &mut DocContext<'tcx>,
104 bindings: Vec<TypeBinding>,
105 substs: SubstsRef<'tcx>,
107 let args = substs_to_args(cx, substs, has_self);
109 if cx.tcx.fn_trait_kind_from_lang_item(did).is_some() {
111 // The trait's first substitution is the one after self, if there is one.
112 match substs.iter().nth(if has_self { 1 } else { 0 }).unwrap().expect_ty().kind() {
113 ty::Tuple(tys) => tys.iter().map(|t| t.clean(cx)).collect::<Vec<_>>().into(),
114 _ => return GenericArgs::AngleBracketed { args: args.into(), bindings: bindings.into() },
117 // FIXME(#20299) return type comes from a projection now
118 // match types[1].kind {
119 // ty::Tuple(ref v) if v.is_empty() => None, // -> ()
120 // _ => Some(types[1].clean(cx))
122 GenericArgs::Parenthesized { inputs, output }
124 GenericArgs::AngleBracketed { args: args.into(), bindings: bindings.into() }
128 pub(super) fn external_path<'tcx>(
129 cx: &mut DocContext<'tcx>,
132 bindings: Vec<TypeBinding>,
133 substs: SubstsRef<'tcx>,
135 let def_kind = cx.tcx.def_kind(did);
136 let name = cx.tcx.item_name(did);
138 res: Res::Def(def_kind, did),
139 segments: vec![PathSegment {
141 args: external_generic_args(cx, did, has_self, bindings, substs),
146 /// Remove the generic arguments from a path.
147 pub(crate) fn strip_path_generics(mut path: Path) -> Path {
148 for ps in path.segments.iter_mut() {
149 ps.args = GenericArgs::AngleBracketed { args: Default::default(), bindings: ThinVec::new() }
155 pub(crate) fn qpath_to_string(p: &hir::QPath<'_>) -> String {
156 let segments = match *p {
157 hir::QPath::Resolved(_, path) => &path.segments,
158 hir::QPath::TypeRelative(_, segment) => return segment.ident.to_string(),
159 hir::QPath::LangItem(lang_item, ..) => return lang_item.name().to_string(),
162 let mut s = String::new();
163 for (i, seg) in segments.iter().enumerate() {
167 if seg.ident.name != kw::PathRoot {
168 s.push_str(seg.ident.as_str());
174 pub(crate) fn build_deref_target_impls(
175 cx: &mut DocContext<'_>,
182 let target = match *item.kind {
183 ItemKind::AssocTypeItem(ref t, _) => &t.type_,
187 if let Some(prim) = target.primitive_type() {
188 let _prof_timer = cx.tcx.sess.prof.generic_activity("build_primitive_inherent_impls");
189 for did in prim.impls(tcx).filter(|did| !did.is_local()) {
190 inline::build_impl(cx, None, did, None, ret);
192 } else if let Type::Path { path } = target {
193 let did = path.def_id();
195 inline::build_impls(cx, None, did, None, ret);
201 pub(crate) fn name_from_pat(p: &hir::Pat<'_>) -> Symbol {
203 debug!("trying to get a name from pattern: {:?}", p);
205 Symbol::intern(&match p.kind {
206 PatKind::Wild | PatKind::Struct(..) => return kw::Underscore,
207 PatKind::Binding(_, _, ident, _) => return ident.name,
208 PatKind::TupleStruct(ref p, ..) | PatKind::Path(ref p) => qpath_to_string(p),
209 PatKind::Or(pats) => {
210 pats.iter().map(|p| name_from_pat(p).to_string()).collect::<Vec<String>>().join(" | ")
212 PatKind::Tuple(elts, _) => format!(
214 elts.iter().map(|p| name_from_pat(p).to_string()).collect::<Vec<String>>().join(", ")
216 PatKind::Box(p) => return name_from_pat(&*p),
217 PatKind::Ref(p, _) => return name_from_pat(&*p),
218 PatKind::Lit(..) => {
220 "tried to get argument name from PatKind::Lit, which is silly in function arguments"
222 return Symbol::intern("()");
224 PatKind::Range(..) => return kw::Underscore,
225 PatKind::Slice(begin, ref mid, end) => {
226 let begin = begin.iter().map(|p| name_from_pat(p).to_string());
227 let mid = mid.as_ref().map(|p| format!("..{}", name_from_pat(&**p))).into_iter();
228 let end = end.iter().map(|p| name_from_pat(p).to_string());
229 format!("[{}]", begin.chain(mid).chain(end).collect::<Vec<_>>().join(", "))
234 pub(crate) fn print_const(cx: &DocContext<'_>, n: ty::Const<'_>) -> String {
236 ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted }) => {
237 let mut s = if let Some(def) = def.as_local() {
238 let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def.did);
239 print_const_expr(cx.tcx, cx.tcx.hir().body_owned_by(hir_id))
241 inline::print_inlined_const(cx.tcx, def.did)
243 if let Some(promoted) = promoted {
244 s.push_str(&format!("::{:?}", promoted))
249 let mut s = n.to_string();
250 // array lengths are obviously usize
251 if s.ends_with("_usize") {
252 let n = s.len() - "_usize".len();
254 if s.ends_with(": ") {
255 let n = s.len() - ": ".len();
264 pub(crate) fn print_evaluated_const(tcx: TyCtxt<'_>, def_id: DefId) -> Option<String> {
265 tcx.const_eval_poly(def_id).ok().and_then(|val| {
266 let ty = tcx.type_of(def_id);
267 match (val, ty.kind()) {
268 (_, &ty::Ref(..)) => None,
269 (ConstValue::Scalar(_), &ty::Adt(_, _)) => None,
270 (ConstValue::Scalar(_), _) => {
271 let const_ = mir::ConstantKind::from_value(val, ty);
272 Some(print_const_with_custom_print_scalar(tcx, const_))
279 fn format_integer_with_underscore_sep(num: &str) -> String {
280 let num_chars: Vec<_> = num.chars().collect();
281 let mut num_start_index = if num_chars.get(0) == Some(&'-') { 1 } else { 0 };
282 let chunk_size = match num[num_start_index..].as_bytes() {
283 [b'0', b'b' | b'x', ..] => {
284 num_start_index += 2;
287 [b'0', b'o', ..] => {
288 num_start_index += 2;
289 let remaining_chars = num_chars.len() - num_start_index;
290 if remaining_chars <= 6 {
291 // don't add underscores to Unix permissions like 0755 or 100755
292 return num.to_string();
299 num_chars[..num_start_index]
301 .chain(num_chars[num_start_index..].rchunks(chunk_size).rev().intersperse(&['_']).flatten())
305 fn print_const_with_custom_print_scalar(tcx: TyCtxt<'_>, ct: mir::ConstantKind<'_>) -> String {
306 // Use a slightly different format for integer types which always shows the actual value.
307 // For all other types, fallback to the original `pretty_print_const`.
308 match (ct, ct.ty().kind()) {
309 (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Uint(ui)) => {
310 format!("{}{}", format_integer_with_underscore_sep(&int.to_string()), ui.name_str())
312 (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Int(i)) => {
313 let ty = tcx.lift(ct.ty()).unwrap();
314 let size = tcx.layout_of(ty::ParamEnv::empty().and(ty)).unwrap().size;
315 let data = int.assert_bits(size);
316 let sign_extended_data = size.sign_extend(data) as i128;
319 format_integer_with_underscore_sep(&sign_extended_data.to_string()),
327 pub(crate) fn is_literal_expr(tcx: TyCtxt<'_>, hir_id: hir::HirId) -> bool {
328 if let hir::Node::Expr(expr) = tcx.hir().get(hir_id) {
329 if let hir::ExprKind::Lit(_) = &expr.kind {
333 if let hir::ExprKind::Unary(hir::UnOp::Neg, expr) = &expr.kind {
334 if let hir::ExprKind::Lit(_) = &expr.kind {
343 /// Build a textual representation of an unevaluated constant expression.
345 /// If the const expression is too complex, an underscore `_` is returned.
346 /// For const arguments, it's `{ _ }` to be precise.
347 /// This means that the output is not necessarily valid Rust code.
351 /// * literals (optionally with a leading `-`)
353 /// * blocks (`{ … }`) around simple expressions and
354 /// * paths without arguments
356 /// are considered simple enough. Simple blocks are included since they are
357 /// necessary to disambiguate unit from the unit type.
358 /// This list might get extended in the future.
360 /// Without this censoring, in a lot of cases the output would get too large
361 /// and verbose. Consider `match` expressions, blocks and deeply nested ADTs.
362 /// Further, private and `doc(hidden)` fields of structs would get leaked
363 /// since HIR datatypes like the `body` parameter do not contain enough
364 /// semantic information for this function to be able to hide them –
365 /// at least not without significant performance overhead.
367 /// Whenever possible, prefer to evaluate the constant first and try to
368 /// use a different method for pretty-printing. Ideally this function
369 /// should only ever be used as a fallback.
370 pub(crate) fn print_const_expr(tcx: TyCtxt<'_>, body: hir::BodyId) -> String {
372 let value = &hir.body(body).value;
374 #[derive(PartialEq, Eq)]
375 enum Classification {
381 use Classification::*;
383 fn classify(expr: &hir::Expr<'_>) -> Classification {
385 hir::ExprKind::Unary(hir::UnOp::Neg, expr) => {
386 if matches!(expr.kind, hir::ExprKind::Lit(_)) { Literal } else { Complex }
388 hir::ExprKind::Lit(_) => Literal,
389 hir::ExprKind::Tup([]) => Simple,
390 hir::ExprKind::Block(hir::Block { stmts: [], expr: Some(expr), .. }, _) => {
391 if classify(expr) == Complex { Complex } else { Simple }
393 // Paths with a self-type or arguments are too “complex” following our measure since
394 // they may leak private fields of structs (with feature `adt_const_params`).
395 // Consider: `<Self as Trait<{ Struct { private: () } }>>::CONSTANT`.
396 // Paths without arguments are definitely harmless though.
397 hir::ExprKind::Path(hir::QPath::Resolved(_, hir::Path { segments, .. })) => {
398 if segments.iter().all(|segment| segment.args.is_none()) { Simple } else { Complex }
400 // FIXME: Claiming that those kinds of QPaths are simple is probably not true if the Ty
401 // contains const arguments. Is there a *concise* way to check for this?
402 hir::ExprKind::Path(hir::QPath::TypeRelative(..)) => Simple,
403 // FIXME: Can they contain const arguments and thus leak private struct fields?
404 hir::ExprKind::Path(hir::QPath::LangItem(..)) => Simple,
409 let classification = classify(value);
411 if classification == Literal
412 && !value.span.from_expansion()
413 && let Ok(snippet) = tcx.sess.source_map().span_to_snippet(value.span) {
414 // For literals, we avoid invoking the pretty-printer and use the source snippet instead to
415 // preserve certain stylistic choices the user likely made for the sake legibility like
417 // * hexadecimal notation
419 // * character escapes
421 // FIXME: This passes through `-/*spacer*/0` verbatim.
423 } else if classification == Simple {
424 // Otherwise we prefer pretty-printing to get rid of extraneous whitespace, comments and
425 // other formatting artifacts.
426 rustc_hir_pretty::id_to_string(&hir, body.hir_id)
427 } else if tcx.def_kind(hir.body_owner_def_id(body).to_def_id()) == DefKind::AnonConst {
428 // FIXME: Omit the curly braces if the enclosing expression is an array literal
429 // with a repeated element (an `ExprKind::Repeat`) as in such case it
430 // would not actually need any disambiguation.
437 /// Given a type Path, resolve it to a Type using the TyCtxt
438 pub(crate) fn resolve_type(cx: &mut DocContext<'_>, path: Path) -> Type {
439 debug!("resolve_type({:?})", path);
442 Res::PrimTy(p) => Primitive(PrimitiveType::from(p)),
443 Res::SelfTy { .. } if path.segments.len() == 1 => Generic(kw::SelfUpper),
444 Res::Def(DefKind::TyParam, _) if path.segments.len() == 1 => Generic(path.segments[0].name),
446 let _ = register_res(cx, path.res);
452 pub(crate) fn get_auto_trait_and_blanket_impls(
453 cx: &mut DocContext<'_>,
455 ) -> impl Iterator<Item = Item> {
459 .generic_activity("get_auto_trait_impls")
460 .run(|| AutoTraitFinder::new(cx).get_auto_trait_impls(item_def_id));
461 let blanket_impls = cx
464 .generic_activity("get_blanket_impls")
465 .run(|| BlanketImplFinder { cx }.get_blanket_impls(item_def_id));
466 auto_impls.into_iter().chain(blanket_impls)
469 /// If `res` has a documentation page associated, store it in the cache.
471 /// This is later used by [`href()`] to determine the HTML link for the item.
473 /// [`href()`]: crate::html::format::href
474 pub(crate) fn register_res(cx: &mut DocContext<'_>, res: Res) -> DefId {
476 debug!("register_res({:?})", res);
478 let (did, kind) = match res {
479 // These should be added to the cache using `record_extern_fqn`.
481 kind @ (AssocTy | AssocFn | AssocConst | Variant | Fn | TyAlias | Enum | Trait | Struct
482 | Union | Mod | ForeignTy | Const | Static(_) | Macro(..) | TraitAlias),
484 ) => (i, kind.into()),
485 // This is part of a trait definition or trait impl; document the trait.
486 Res::SelfTy { trait_: Some(trait_def_id), alias_to: _ } => (trait_def_id, ItemType::Trait),
487 // This is an inherent impl or a type definition; it doesn't have its own page.
488 Res::SelfTy { trait_: None, alias_to: Some((item_def_id, _)) } => return item_def_id,
489 Res::SelfTy { trait_: None, alias_to: None }
494 | Res::NonMacroAttr(_)
495 | Res::Err => return res.def_id(),
497 TyParam | ConstParam | Ctor(..) | ExternCrate | Use | ForeignMod | AnonConst
498 | InlineConst | OpaqueTy | Field | LifetimeParam | GlobalAsm | Impl | Closure
506 inline::record_extern_fqn(cx, did, kind);
507 if let ItemType::Trait = kind {
508 inline::record_extern_trait(cx, did);
513 pub(crate) fn resolve_use_source(cx: &mut DocContext<'_>, path: Path) -> ImportSource {
515 did: if path.res.opt_def_id().is_none() { None } else { Some(register_res(cx, path.res)) },
520 pub(crate) fn enter_impl_trait<'tcx, F, R>(cx: &mut DocContext<'tcx>, f: F) -> R
522 F: FnOnce(&mut DocContext<'tcx>) -> R,
524 let old_bounds = mem::take(&mut cx.impl_trait_bounds);
526 assert!(cx.impl_trait_bounds.is_empty());
527 cx.impl_trait_bounds = old_bounds;
531 /// Find the nearest parent module of a [`DefId`].
532 pub(crate) fn find_nearest_parent_module(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
533 if def_id.is_top_level_module() {
534 // The crate root has no parent. Use it as the root instead.
537 let mut current = def_id;
538 // The immediate parent might not always be a module.
539 // Find the first parent which is.
540 while let Some(parent) = tcx.opt_parent(current) {
541 if tcx.def_kind(parent) == DefKind::Mod {
550 /// Checks for the existence of `hidden` in the attribute below if `flag` is `sym::hidden`:
557 /// This function exists because it runs on `hir::Attributes` whereas the other is a
558 /// `clean::Attributes` method.
559 pub(crate) fn has_doc_flag(tcx: TyCtxt<'_>, did: DefId, flag: Symbol) -> bool {
560 tcx.get_attrs(did, sym::doc).any(|attr| {
561 attr.meta_item_list().map_or(false, |l| rustc_attr::list_contains_name(&l, flag))
565 /// A link to `doc.rust-lang.org` that includes the channel name. Use this instead of manual links
566 /// so that the channel is consistent.
568 /// Set by `bootstrap::Builder::doc_rust_lang_org_channel` in order to keep tests passing on beta/stable.
569 pub(crate) const DOC_RUST_LANG_ORG_CHANNEL: &str = env!("DOC_RUST_LANG_ORG_CHANNEL");
571 /// Render a sequence of macro arms in a format suitable for displaying to the user
572 /// as part of an item declaration.
573 pub(super) fn render_macro_arms<'a>(
575 matchers: impl Iterator<Item = &'a TokenTree>,
578 let mut out = String::new();
579 for matcher in matchers {
580 writeln!(out, " {} => {{ ... }}{}", render_macro_matcher(tcx, matcher), arm_delim)
586 pub(super) fn display_macro_source(
587 cx: &mut DocContext<'_>,
593 let tts: Vec<_> = def.body.inner_tokens().into_trees().collect();
594 // Extract the spans of all matchers. They represent the "interface" of the macro.
595 let matchers = tts.chunks(4).map(|arm| &arm[0]);
598 format!("macro_rules! {} {{\n{}}}", name, render_macro_arms(cx.tcx, matchers, ";"))
600 if matchers.len() <= 1 {
602 "{}macro {}{} {{\n ...\n}}",
603 vis.to_src_with_space(cx.tcx, def_id),
605 matchers.map(|matcher| render_macro_matcher(cx.tcx, matcher)).collect::<String>(),
609 "{}macro {} {{\n{}}}",
610 vis.to_src_with_space(cx.tcx, def_id),
612 render_macro_arms(cx.tcx, matchers, ","),