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 clean_doc_module, clean_middle_const, clean_middle_region, clean_middle_ty, inline, Crate,
6 ExternalCrate, Generic, GenericArg, GenericArgs, ImportSource, Item, ItemKind, Lifetime, Path,
7 PathSegment, Primitive, PrimitiveType, Term, Type, TypeBinding, TypeBindingKind,
9 use crate::core::DocContext;
10 use crate::html::format::visibility_to_src_with_space;
13 use rustc_ast::tokenstream::TokenTree;
15 use rustc_hir::def::{DefKind, Res};
16 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
17 use rustc_middle::mir;
18 use rustc_middle::mir::interpret::ConstValue;
19 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
20 use rustc_middle::ty::{self, DefIdTree, TyCtxt};
21 use rustc_span::symbol::{kw, sym, Symbol};
22 use std::fmt::Write as _;
24 use thin_vec::{thin_vec, ThinVec};
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 crate::visit_lib::lib_embargo_visit_item(cx, cnum.as_def_id());
37 // Clean the crate, translating the entire librustc_ast AST to one that is
38 // understood by rustdoc.
39 let mut module = clean_doc_module(&module, 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, 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(clean_middle_region(lt).unwrap_or(Lifetime::elided())))
90 GenericArgKind::Type(_) if skip_first => {
94 GenericArgKind::Type(ty) => Some(GenericArg::Type(clean_middle_ty(ty, cx, None))),
95 GenericArgKind::Const(ct) => Some(GenericArg::Const(Box::new(clean_middle_const(ct, cx)))),
100 fn external_generic_args<'tcx>(
101 cx: &mut DocContext<'tcx>,
104 bindings: ThinVec<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| clean_middle_ty(t, cx, None)).collect::<Vec<_>>().into(),
114 _ => return GenericArgs::AngleBracketed { args: args.into(), bindings },
116 let output = bindings.into_iter().next().and_then(|binding| match binding.kind {
117 TypeBindingKind::Equality { term: Term::Type(ty) } if ty != Type::Tuple(Vec::new()) => {
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: ThinVec<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: thin_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::UnevaluatedConst { def, substs: _ }) => {
237 let s = if let Some(def) = def.as_local() {
238 print_const_expr(cx.tcx, cx.tcx.hir().body_owned_by(def.did))
240 inline::print_inlined_const(cx.tcx, def.did)
245 // array lengths are obviously usize
246 ty::ConstKind::Value(ty::ValTree::Leaf(scalar))
247 if *n.ty().kind() == ty::Uint(ty::UintTy::Usize) =>
255 pub(crate) fn print_evaluated_const(
258 underscores_and_type: bool,
259 ) -> Option<String> {
260 tcx.const_eval_poly(def_id).ok().and_then(|val| {
261 let ty = tcx.type_of(def_id);
262 match (val, ty.kind()) {
263 (_, &ty::Ref(..)) => None,
264 (ConstValue::Scalar(_), &ty::Adt(_, _)) => None,
265 (ConstValue::Scalar(_), _) => {
266 let const_ = mir::ConstantKind::from_value(val, ty);
267 Some(print_const_with_custom_print_scalar(tcx, const_, underscores_and_type))
274 fn format_integer_with_underscore_sep(num: &str) -> String {
275 let num_chars: Vec<_> = num.chars().collect();
276 let mut num_start_index = if num_chars.get(0) == Some(&'-') { 1 } else { 0 };
277 let chunk_size = match num[num_start_index..].as_bytes() {
278 [b'0', b'b' | b'x', ..] => {
279 num_start_index += 2;
282 [b'0', b'o', ..] => {
283 num_start_index += 2;
284 let remaining_chars = num_chars.len() - num_start_index;
285 if remaining_chars <= 6 {
286 // don't add underscores to Unix permissions like 0755 or 100755
287 return num.to_string();
294 num_chars[..num_start_index]
296 .chain(num_chars[num_start_index..].rchunks(chunk_size).rev().intersperse(&['_']).flatten())
300 fn print_const_with_custom_print_scalar<'tcx>(
302 ct: mir::ConstantKind<'tcx>,
303 underscores_and_type: bool,
305 // Use a slightly different format for integer types which always shows the actual value.
306 // For all other types, fallback to the original `pretty_print_const`.
307 match (ct, ct.ty().kind()) {
308 (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Uint(ui)) => {
309 if underscores_and_type {
310 format!("{}{}", format_integer_with_underscore_sep(&int.to_string()), ui.name_str())
315 (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Int(i)) => {
317 let size = tcx.layout_of(ty::ParamEnv::empty().and(ty)).unwrap().size;
318 let data = int.assert_bits(size);
319 let sign_extended_data = size.sign_extend(data) as i128;
320 if underscores_and_type {
323 format_integer_with_underscore_sep(&sign_extended_data.to_string()),
327 sign_extended_data.to_string()
334 pub(crate) fn is_literal_expr(tcx: TyCtxt<'_>, hir_id: hir::HirId) -> bool {
335 if let hir::Node::Expr(expr) = tcx.hir().get(hir_id) {
336 if let hir::ExprKind::Lit(_) = &expr.kind {
340 if let hir::ExprKind::Unary(hir::UnOp::Neg, expr) = &expr.kind {
341 if let hir::ExprKind::Lit(_) = &expr.kind {
350 /// Build a textual representation of an unevaluated constant expression.
352 /// If the const expression is too complex, an underscore `_` is returned.
353 /// For const arguments, it's `{ _ }` to be precise.
354 /// This means that the output is not necessarily valid Rust code.
358 /// * literals (optionally with a leading `-`)
360 /// * blocks (`{ … }`) around simple expressions and
361 /// * paths without arguments
363 /// are considered simple enough. Simple blocks are included since they are
364 /// necessary to disambiguate unit from the unit type.
365 /// This list might get extended in the future.
367 /// Without this censoring, in a lot of cases the output would get too large
368 /// and verbose. Consider `match` expressions, blocks and deeply nested ADTs.
369 /// Further, private and `doc(hidden)` fields of structs would get leaked
370 /// since HIR datatypes like the `body` parameter do not contain enough
371 /// semantic information for this function to be able to hide them –
372 /// at least not without significant performance overhead.
374 /// Whenever possible, prefer to evaluate the constant first and try to
375 /// use a different method for pretty-printing. Ideally this function
376 /// should only ever be used as a fallback.
377 pub(crate) fn print_const_expr(tcx: TyCtxt<'_>, body: hir::BodyId) -> String {
379 let value = &hir.body(body).value;
381 #[derive(PartialEq, Eq)]
382 enum Classification {
388 use Classification::*;
390 fn classify(expr: &hir::Expr<'_>) -> Classification {
392 hir::ExprKind::Unary(hir::UnOp::Neg, expr) => {
393 if matches!(expr.kind, hir::ExprKind::Lit(_)) { Literal } else { Complex }
395 hir::ExprKind::Lit(_) => Literal,
396 hir::ExprKind::Tup([]) => Simple,
397 hir::ExprKind::Block(hir::Block { stmts: [], expr: Some(expr), .. }, _) => {
398 if classify(expr) == Complex { Complex } else { Simple }
400 // Paths with a self-type or arguments are too “complex” following our measure since
401 // they may leak private fields of structs (with feature `adt_const_params`).
402 // Consider: `<Self as Trait<{ Struct { private: () } }>>::CONSTANT`.
403 // Paths without arguments are definitely harmless though.
404 hir::ExprKind::Path(hir::QPath::Resolved(_, hir::Path { segments, .. })) => {
405 if segments.iter().all(|segment| segment.args.is_none()) { Simple } else { Complex }
407 // FIXME: Claiming that those kinds of QPaths are simple is probably not true if the Ty
408 // contains const arguments. Is there a *concise* way to check for this?
409 hir::ExprKind::Path(hir::QPath::TypeRelative(..)) => Simple,
410 // FIXME: Can they contain const arguments and thus leak private struct fields?
411 hir::ExprKind::Path(hir::QPath::LangItem(..)) => Simple,
416 let classification = classify(value);
418 if classification == Literal
419 && !value.span.from_expansion()
420 && let Ok(snippet) = tcx.sess.source_map().span_to_snippet(value.span) {
421 // For literals, we avoid invoking the pretty-printer and use the source snippet instead to
422 // preserve certain stylistic choices the user likely made for the sake legibility like
424 // * hexadecimal notation
426 // * character escapes
428 // FIXME: This passes through `-/*spacer*/0` verbatim.
430 } else if classification == Simple {
431 // Otherwise we prefer pretty-printing to get rid of extraneous whitespace, comments and
432 // other formatting artifacts.
433 rustc_hir_pretty::id_to_string(&hir, body.hir_id)
434 } else if tcx.def_kind(hir.body_owner_def_id(body).to_def_id()) == DefKind::AnonConst {
435 // FIXME: Omit the curly braces if the enclosing expression is an array literal
436 // with a repeated element (an `ExprKind::Repeat`) as in such case it
437 // would not actually need any disambiguation.
444 /// Given a type Path, resolve it to a Type using the TyCtxt
445 pub(crate) fn resolve_type(cx: &mut DocContext<'_>, path: Path) -> Type {
446 debug!("resolve_type({:?})", path);
449 Res::PrimTy(p) => Primitive(PrimitiveType::from(p)),
450 Res::SelfTyParam { .. } | Res::SelfTyAlias { .. } if path.segments.len() == 1 => {
451 Generic(kw::SelfUpper)
453 Res::Def(DefKind::TyParam, _) if path.segments.len() == 1 => Generic(path.segments[0].name),
455 let _ = register_res(cx, path.res);
461 pub(crate) fn get_auto_trait_and_blanket_impls(
462 cx: &mut DocContext<'_>,
464 ) -> impl Iterator<Item = Item> {
468 .generic_activity("get_auto_trait_impls")
469 .run(|| AutoTraitFinder::new(cx).get_auto_trait_impls(item_def_id));
470 let blanket_impls = cx
473 .generic_activity("get_blanket_impls")
474 .run(|| BlanketImplFinder { cx }.get_blanket_impls(item_def_id));
475 auto_impls.into_iter().chain(blanket_impls)
478 /// If `res` has a documentation page associated, store it in the cache.
480 /// This is later used by [`href()`] to determine the HTML link for the item.
482 /// [`href()`]: crate::html::format::href
483 pub(crate) fn register_res(cx: &mut DocContext<'_>, res: Res) -> DefId {
485 debug!("register_res({:?})", res);
487 let (kind, did) = match res {
489 kind @ (AssocTy | AssocFn | AssocConst | Variant | Fn | TyAlias | Enum | Trait | Struct
490 | Union | Mod | ForeignTy | Const | Static(_) | Macro(..) | TraitAlias),
492 ) => (kind.into(), did),
494 _ => panic!("register_res: unexpected {:?}", res),
499 inline::record_extern_fqn(cx, did, kind);
503 pub(crate) fn resolve_use_source(cx: &mut DocContext<'_>, path: Path) -> ImportSource {
505 did: if path.res.opt_def_id().is_none() { None } else { Some(register_res(cx, path.res)) },
510 pub(crate) fn enter_impl_trait<'tcx, F, R>(cx: &mut DocContext<'tcx>, f: F) -> R
512 F: FnOnce(&mut DocContext<'tcx>) -> R,
514 let old_bounds = mem::take(&mut cx.impl_trait_bounds);
516 assert!(cx.impl_trait_bounds.is_empty());
517 cx.impl_trait_bounds = old_bounds;
521 /// Find the nearest parent module of a [`DefId`].
522 pub(crate) fn find_nearest_parent_module(tcx: TyCtxt<'_>, def_id: DefId) -> Option<DefId> {
523 if def_id.is_top_level_module() {
524 // The crate root has no parent. Use it as the root instead.
527 let mut current = def_id;
528 // The immediate parent might not always be a module.
529 // Find the first parent which is.
530 while let Some(parent) = tcx.opt_parent(current) {
531 if tcx.def_kind(parent) == DefKind::Mod {
540 /// Checks for the existence of `hidden` in the attribute below if `flag` is `sym::hidden`:
547 /// This function exists because it runs on `hir::Attributes` whereas the other is a
548 /// `clean::Attributes` method.
549 pub(crate) fn has_doc_flag(tcx: TyCtxt<'_>, did: DefId, flag: Symbol) -> bool {
550 tcx.get_attrs(did, sym::doc).any(|attr| {
551 attr.meta_item_list().map_or(false, |l| rustc_attr::list_contains_name(&l, flag))
555 /// A link to `doc.rust-lang.org` that includes the channel name. Use this instead of manual links
556 /// so that the channel is consistent.
558 /// Set by `bootstrap::Builder::doc_rust_lang_org_channel` in order to keep tests passing on beta/stable.
559 pub(crate) const DOC_RUST_LANG_ORG_CHANNEL: &str = env!("DOC_RUST_LANG_ORG_CHANNEL");
561 /// Render a sequence of macro arms in a format suitable for displaying to the user
562 /// as part of an item declaration.
563 pub(super) fn render_macro_arms<'a>(
565 matchers: impl Iterator<Item = &'a TokenTree>,
568 let mut out = String::new();
569 for matcher in matchers {
570 writeln!(out, " {} => {{ ... }}{}", render_macro_matcher(tcx, matcher), arm_delim)
576 pub(super) fn display_macro_source(
577 cx: &mut DocContext<'_>,
581 vis: ty::Visibility<DefId>,
583 let tts: Vec<_> = def.body.tokens.clone().into_trees().collect();
584 // Extract the spans of all matchers. They represent the "interface" of the macro.
585 let matchers = tts.chunks(4).map(|arm| &arm[0]);
588 format!("macro_rules! {} {{\n{}}}", name, render_macro_arms(cx.tcx, matchers, ";"))
590 if matchers.len() <= 1 {
592 "{}macro {}{} {{\n ...\n}}",
593 visibility_to_src_with_space(Some(vis), cx.tcx, def_id),
595 matchers.map(|matcher| render_macro_matcher(cx.tcx, matcher)).collect::<String>(),
599 "{}macro {} {{\n{}}}",
600 visibility_to_src_with_space(Some(vis), cx.tcx, def_id),
602 render_macro_arms(cx.tcx, matchers, ","),