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, Type, TypeBinding, Visibility,
9 use crate::core::DocContext;
10 use crate::formats::item_type::ItemType;
11 use crate::visit_lib::LibEmbargoVisitor;
14 use rustc_ast::tokenstream::TokenTree;
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 _;
25 use thin_vec::ThinVec;
30 pub(crate) fn krate(cx: &mut DocContext<'_>) -> Crate {
31 let module = crate::visit_ast::RustdocVisitor::new(cx).visit();
33 for &cnum in cx.tcx.crates(()) {
34 // Analyze doc-reachability for extern items
35 LibEmbargoVisitor::new(cx).visit_lib(cnum);
38 // Clean the crate, translating the entire librustc_ast AST to one that is
39 // understood by rustdoc.
40 let mut module = clean_doc_module(&module, cx);
43 ItemKind::ModuleItem(ref module) => {
44 for it in &module.items {
45 // `compiler_builtins` should be masked too, but we can't apply
46 // `#[doc(masked)]` to the injected `extern crate` because it's unstable.
47 if it.is_extern_crate()
48 && (it.attrs.has_doc_flag(sym::masked)
49 || cx.tcx.is_compiler_builtins(it.item_id.krate()))
51 cx.cache.masked_crates.insert(it.item_id.krate());
58 let local_crate = ExternalCrate { crate_num: LOCAL_CRATE };
59 let primitives = local_crate.primitives(cx.tcx);
60 let keywords = local_crate.keywords(cx.tcx);
62 let ItemKind::ModuleItem(ref mut m) = *module.kind
63 else { unreachable!() };
64 m.items.extend(primitives.iter().map(|&(def_id, prim)| {
65 Item::from_def_id_and_parts(
68 ItemKind::PrimitiveItem(prim),
72 m.items.extend(keywords.into_iter().map(|(def_id, kw)| {
73 Item::from_def_id_and_parts(def_id, Some(kw), ItemKind::KeywordItem, cx)
77 Crate { module, primitives, external_traits: cx.external_traits.clone() }
80 pub(crate) fn substs_to_args<'tcx>(
81 cx: &mut DocContext<'tcx>,
82 substs: &[ty::subst::GenericArg<'tcx>],
84 ) -> Vec<GenericArg> {
86 Vec::with_capacity(substs.len().saturating_sub(if skip_first { 1 } else { 0 }));
87 ret_val.extend(substs.iter().filter_map(|kind| match kind.unpack() {
88 GenericArgKind::Lifetime(lt) => {
89 Some(GenericArg::Lifetime(clean_middle_region(lt).unwrap_or(Lifetime::elided())))
91 GenericArgKind::Type(_) if skip_first => {
95 GenericArgKind::Type(ty) => Some(GenericArg::Type(clean_middle_ty(ty, cx, None))),
96 GenericArgKind::Const(ct) => Some(GenericArg::Const(Box::new(clean_middle_const(ct, cx)))),
101 fn external_generic_args<'tcx>(
102 cx: &mut DocContext<'tcx>,
105 bindings: ThinVec<TypeBinding>,
106 substs: SubstsRef<'tcx>,
108 let args = substs_to_args(cx, substs, has_self);
110 if cx.tcx.fn_trait_kind_from_lang_item(did).is_some() {
112 // The trait's first substitution is the one after self, if there is one.
113 match substs.iter().nth(if has_self { 1 } else { 0 }).unwrap().expect_ty().kind() {
114 ty::Tuple(tys) => tys.iter().map(|t| clean_middle_ty(t, cx, None)).collect::<Vec<_>>().into(),
115 _ => return GenericArgs::AngleBracketed { args: args.into(), bindings },
118 // FIXME(#20299) return type comes from a projection now
119 // match types[1].kind {
120 // ty::Tuple(ref v) if v.is_empty() => None, // -> ()
121 // _ => Some(types[1].clean(cx))
123 GenericArgs::Parenthesized { inputs, output }
125 GenericArgs::AngleBracketed { args: args.into(), bindings: bindings.into() }
129 pub(super) fn external_path<'tcx>(
130 cx: &mut DocContext<'tcx>,
133 bindings: ThinVec<TypeBinding>,
134 substs: SubstsRef<'tcx>,
136 let def_kind = cx.tcx.def_kind(did);
137 let name = cx.tcx.item_name(did);
139 res: Res::Def(def_kind, did),
140 segments: vec![PathSegment {
142 args: external_generic_args(cx, did, has_self, bindings, substs),
147 /// Remove the generic arguments from a path.
148 pub(crate) fn strip_path_generics(mut path: Path) -> Path {
149 for ps in path.segments.iter_mut() {
150 ps.args = GenericArgs::AngleBracketed { args: Default::default(), bindings: ThinVec::new() }
156 pub(crate) fn qpath_to_string(p: &hir::QPath<'_>) -> String {
157 let segments = match *p {
158 hir::QPath::Resolved(_, path) => &path.segments,
159 hir::QPath::TypeRelative(_, segment) => return segment.ident.to_string(),
160 hir::QPath::LangItem(lang_item, ..) => return lang_item.name().to_string(),
163 let mut s = String::new();
164 for (i, seg) in segments.iter().enumerate() {
168 if seg.ident.name != kw::PathRoot {
169 s.push_str(seg.ident.as_str());
175 pub(crate) fn build_deref_target_impls(
176 cx: &mut DocContext<'_>,
183 let target = match *item.kind {
184 ItemKind::AssocTypeItem(ref t, _) => &t.type_,
188 if let Some(prim) = target.primitive_type() {
189 let _prof_timer = cx.tcx.sess.prof.generic_activity("build_primitive_inherent_impls");
190 for did in prim.impls(tcx).filter(|did| !did.is_local()) {
191 inline::build_impl(cx, None, did, None, ret);
193 } else if let Type::Path { path } = target {
194 let did = path.def_id();
196 inline::build_impls(cx, None, did, None, ret);
202 pub(crate) fn name_from_pat(p: &hir::Pat<'_>) -> Symbol {
204 debug!("trying to get a name from pattern: {:?}", p);
206 Symbol::intern(&match p.kind {
207 PatKind::Wild | PatKind::Struct(..) => return kw::Underscore,
208 PatKind::Binding(_, _, ident, _) => return ident.name,
209 PatKind::TupleStruct(ref p, ..) | PatKind::Path(ref p) => qpath_to_string(p),
210 PatKind::Or(pats) => {
211 pats.iter().map(|p| name_from_pat(p).to_string()).collect::<Vec<String>>().join(" | ")
213 PatKind::Tuple(elts, _) => format!(
215 elts.iter().map(|p| name_from_pat(p).to_string()).collect::<Vec<String>>().join(", ")
217 PatKind::Box(p) => return name_from_pat(&*p),
218 PatKind::Ref(p, _) => return name_from_pat(&*p),
219 PatKind::Lit(..) => {
221 "tried to get argument name from PatKind::Lit, which is silly in function arguments"
223 return Symbol::intern("()");
225 PatKind::Range(..) => return kw::Underscore,
226 PatKind::Slice(begin, ref mid, end) => {
227 let begin = begin.iter().map(|p| name_from_pat(p).to_string());
228 let mid = mid.as_ref().map(|p| format!("..{}", name_from_pat(&**p))).into_iter();
229 let end = end.iter().map(|p| name_from_pat(p).to_string());
230 format!("[{}]", begin.chain(mid).chain(end).collect::<Vec<_>>().join(", "))
235 pub(crate) fn print_const(cx: &DocContext<'_>, n: ty::Const<'_>) -> String {
237 ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs: _ }) => {
238 let s = if let Some(def) = def.as_local() {
239 print_const_expr(cx.tcx, cx.tcx.hir().body_owned_by(def.did))
241 inline::print_inlined_const(cx.tcx, def.did)
247 let mut s = n.to_string();
248 // array lengths are obviously usize
249 if s.ends_with("_usize") {
250 let n = s.len() - "_usize".len();
252 if s.ends_with(": ") {
253 let n = s.len() - ": ".len();
262 pub(crate) fn print_evaluated_const(
265 underscores_and_type: bool,
266 ) -> Option<String> {
267 tcx.const_eval_poly(def_id).ok().and_then(|val| {
268 let ty = tcx.type_of(def_id);
269 match (val, ty.kind()) {
270 (_, &ty::Ref(..)) => None,
271 (ConstValue::Scalar(_), &ty::Adt(_, _)) => None,
272 (ConstValue::Scalar(_), _) => {
273 let const_ = mir::ConstantKind::from_value(val, ty);
274 Some(print_const_with_custom_print_scalar(tcx, const_, underscores_and_type))
281 fn format_integer_with_underscore_sep(num: &str) -> String {
282 let num_chars: Vec<_> = num.chars().collect();
283 let mut num_start_index = if num_chars.get(0) == Some(&'-') { 1 } else { 0 };
284 let chunk_size = match num[num_start_index..].as_bytes() {
285 [b'0', b'b' | b'x', ..] => {
286 num_start_index += 2;
289 [b'0', b'o', ..] => {
290 num_start_index += 2;
291 let remaining_chars = num_chars.len() - num_start_index;
292 if remaining_chars <= 6 {
293 // don't add underscores to Unix permissions like 0755 or 100755
294 return num.to_string();
301 num_chars[..num_start_index]
303 .chain(num_chars[num_start_index..].rchunks(chunk_size).rev().intersperse(&['_']).flatten())
307 fn print_const_with_custom_print_scalar<'tcx>(
309 ct: mir::ConstantKind<'tcx>,
310 underscores_and_type: bool,
312 // Use a slightly different format for integer types which always shows the actual value.
313 // For all other types, fallback to the original `pretty_print_const`.
314 match (ct, ct.ty().kind()) {
315 (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Uint(ui)) => {
316 if underscores_and_type {
317 format!("{}{}", format_integer_with_underscore_sep(&int.to_string()), ui.name_str())
322 (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Int(i)) => {
324 let size = tcx.layout_of(ty::ParamEnv::empty().and(ty)).unwrap().size;
325 let data = int.assert_bits(size);
326 let sign_extended_data = size.sign_extend(data) as i128;
327 if underscores_and_type {
330 format_integer_with_underscore_sep(&sign_extended_data.to_string()),
334 sign_extended_data.to_string()
341 pub(crate) fn is_literal_expr(tcx: TyCtxt<'_>, hir_id: hir::HirId) -> bool {
342 if let hir::Node::Expr(expr) = tcx.hir().get(hir_id) {
343 if let hir::ExprKind::Lit(_) = &expr.kind {
347 if let hir::ExprKind::Unary(hir::UnOp::Neg, expr) = &expr.kind {
348 if let hir::ExprKind::Lit(_) = &expr.kind {
357 /// Build a textual representation of an unevaluated constant expression.
359 /// If the const expression is too complex, an underscore `_` is returned.
360 /// For const arguments, it's `{ _ }` to be precise.
361 /// This means that the output is not necessarily valid Rust code.
365 /// * literals (optionally with a leading `-`)
367 /// * blocks (`{ … }`) around simple expressions and
368 /// * paths without arguments
370 /// are considered simple enough. Simple blocks are included since they are
371 /// necessary to disambiguate unit from the unit type.
372 /// This list might get extended in the future.
374 /// Without this censoring, in a lot of cases the output would get too large
375 /// and verbose. Consider `match` expressions, blocks and deeply nested ADTs.
376 /// Further, private and `doc(hidden)` fields of structs would get leaked
377 /// since HIR datatypes like the `body` parameter do not contain enough
378 /// semantic information for this function to be able to hide them –
379 /// at least not without significant performance overhead.
381 /// Whenever possible, prefer to evaluate the constant first and try to
382 /// use a different method for pretty-printing. Ideally this function
383 /// should only ever be used as a fallback.
384 pub(crate) fn print_const_expr(tcx: TyCtxt<'_>, body: hir::BodyId) -> String {
386 let value = &hir.body(body).value;
388 #[derive(PartialEq, Eq)]
389 enum Classification {
395 use Classification::*;
397 fn classify(expr: &hir::Expr<'_>) -> Classification {
399 hir::ExprKind::Unary(hir::UnOp::Neg, expr) => {
400 if matches!(expr.kind, hir::ExprKind::Lit(_)) { Literal } else { Complex }
402 hir::ExprKind::Lit(_) => Literal,
403 hir::ExprKind::Tup([]) => Simple,
404 hir::ExprKind::Block(hir::Block { stmts: [], expr: Some(expr), .. }, _) => {
405 if classify(expr) == Complex { Complex } else { Simple }
407 // Paths with a self-type or arguments are too “complex” following our measure since
408 // they may leak private fields of structs (with feature `adt_const_params`).
409 // Consider: `<Self as Trait<{ Struct { private: () } }>>::CONSTANT`.
410 // Paths without arguments are definitely harmless though.
411 hir::ExprKind::Path(hir::QPath::Resolved(_, hir::Path { segments, .. })) => {
412 if segments.iter().all(|segment| segment.args.is_none()) { Simple } else { Complex }
414 // FIXME: Claiming that those kinds of QPaths are simple is probably not true if the Ty
415 // contains const arguments. Is there a *concise* way to check for this?
416 hir::ExprKind::Path(hir::QPath::TypeRelative(..)) => Simple,
417 // FIXME: Can they contain const arguments and thus leak private struct fields?
418 hir::ExprKind::Path(hir::QPath::LangItem(..)) => Simple,
423 let classification = classify(value);
425 if classification == Literal
426 && !value.span.from_expansion()
427 && let Ok(snippet) = tcx.sess.source_map().span_to_snippet(value.span) {
428 // For literals, we avoid invoking the pretty-printer and use the source snippet instead to
429 // preserve certain stylistic choices the user likely made for the sake legibility like
431 // * hexadecimal notation
433 // * character escapes
435 // FIXME: This passes through `-/*spacer*/0` verbatim.
437 } else if classification == Simple {
438 // Otherwise we prefer pretty-printing to get rid of extraneous whitespace, comments and
439 // other formatting artifacts.
440 rustc_hir_pretty::id_to_string(&hir, body.hir_id)
441 } else if tcx.def_kind(hir.body_owner_def_id(body).to_def_id()) == DefKind::AnonConst {
442 // FIXME: Omit the curly braces if the enclosing expression is an array literal
443 // with a repeated element (an `ExprKind::Repeat`) as in such case it
444 // would not actually need any disambiguation.
451 /// Given a type Path, resolve it to a Type using the TyCtxt
452 pub(crate) fn resolve_type(cx: &mut DocContext<'_>, path: Path) -> Type {
453 debug!("resolve_type({:?})", path);
456 Res::PrimTy(p) => Primitive(PrimitiveType::from(p)),
457 Res::SelfTyParam { .. } | Res::SelfTyAlias { .. } if path.segments.len() == 1 => {
458 Generic(kw::SelfUpper)
460 Res::Def(DefKind::TyParam, _) if path.segments.len() == 1 => Generic(path.segments[0].name),
462 let _ = register_res(cx, path.res);
468 pub(crate) fn get_auto_trait_and_blanket_impls(
469 cx: &mut DocContext<'_>,
471 ) -> impl Iterator<Item = Item> {
475 .generic_activity("get_auto_trait_impls")
476 .run(|| AutoTraitFinder::new(cx).get_auto_trait_impls(item_def_id));
477 let blanket_impls = cx
480 .generic_activity("get_blanket_impls")
481 .run(|| BlanketImplFinder { cx }.get_blanket_impls(item_def_id));
482 auto_impls.into_iter().chain(blanket_impls)
485 /// If `res` has a documentation page associated, store it in the cache.
487 /// This is later used by [`href()`] to determine the HTML link for the item.
489 /// [`href()`]: crate::html::format::href
490 pub(crate) fn register_res(cx: &mut DocContext<'_>, res: Res) -> DefId {
492 debug!("register_res({:?})", res);
494 let (kind, did) = match res {
496 kind @ (AssocTy | AssocFn | AssocConst | Variant | Fn | TyAlias | Enum | Trait | Struct
497 | Union | Mod | ForeignTy | Const | Static(_) | Macro(..) | TraitAlias),
499 ) => (kind.into(), did),
501 _ => panic!("register_res: unexpected {:?}", res),
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, ","),