1 use crate::utils::{implements_trait, is_entrypoint_fn, is_type_diagnostic_item, return_ty, span_lint};
2 use if_chain::if_chain;
3 use itertools::Itertools;
4 use rustc_ast::ast::{AttrKind, Attribute};
5 use rustc_data_structures::fx::FxHashSet;
7 use rustc_lint::{LateContext, LateLintPass};
8 use rustc_middle::lint::in_external_macro;
10 use rustc_session::{declare_tool_lint, impl_lint_pass};
11 use rustc_span::source_map::{BytePos, MultiSpan, Span};
16 declare_clippy_lint! {
17 /// **What it does:** Checks for the presence of `_`, `::` or camel-case words
18 /// outside ticks in documentation.
20 /// **Why is this bad?** *Rustdoc* supports markdown formatting, `_`, `::` and
21 /// camel-case probably indicates some code which should be included between
22 /// ticks. `_` can also be used for emphasis in markdown, this lint tries to
25 /// **Known problems:** Lots of bad docs won’t be fixed, what the lint checks
26 /// for is limited, and there are still false positives.
30 /// /// Do something with the foo_bar parameter. See also
31 /// /// that::other::module::foo.
32 /// // ^ `foo_bar` and `that::other::module::foo` should be ticked.
33 /// fn doit(foo_bar: usize) {}
37 "presence of `_`, `::` or camel-case outside backticks in documentation"
40 declare_clippy_lint! {
41 /// **What it does:** Checks for the doc comments of publicly visible
42 /// unsafe functions and warns if there is no `# Safety` section.
44 /// **Why is this bad?** Unsafe functions should document their safety
45 /// preconditions, so that users can be sure they are using them safely.
47 /// **Known problems:** None.
51 ///# type Universe = ();
52 /// /// This function should really be documented
53 /// pub unsafe fn start_apocalypse(u: &mut Universe) {
58 /// At least write a line about safety:
61 ///# type Universe = ();
64 /// /// This function should not be called before the horsemen are ready.
65 /// pub unsafe fn start_apocalypse(u: &mut Universe) {
69 pub MISSING_SAFETY_DOC,
71 "`pub unsafe fn` without `# Safety` docs"
74 declare_clippy_lint! {
75 /// **What it does:** Checks the doc comments of publicly visible functions that
76 /// return a `Result` type and warns if there is no `# Errors` section.
78 /// **Why is this bad?** Documenting the type of errors that can be returned from a
79 /// function can help callers write code to handle the errors appropriately.
81 /// **Known problems:** None.
85 /// Since the following function returns a `Result` it has an `# Errors` section in
92 /// /// Will return `Err` if `filename` does not exist or the user does not have
93 /// /// permission to read it.
94 /// pub fn read(filename: String) -> io::Result<String> {
98 pub MISSING_ERRORS_DOC,
100 "`pub fn` returns `Result` without `# Errors` in doc comment"
103 declare_clippy_lint! {
104 /// **What it does:** Checks for `fn main() { .. }` in doctests
106 /// **Why is this bad?** The test can be shorter (and likely more readable)
107 /// if the `fn main()` is left implicit.
109 /// **Known problems:** None.
113 /// /// An example of a doctest with a `main()` function
119 /// /// // this needs not be in an `fn`
122 /// fn needless_main() {
123 /// unimplemented!();
126 pub NEEDLESS_DOCTEST_MAIN,
128 "presence of `fn main() {` in code examples"
131 #[allow(clippy::module_name_repetitions)]
133 pub struct DocMarkdown {
134 valid_idents: FxHashSet<String>,
139 pub fn new(valid_idents: FxHashSet<String>) -> Self {
142 in_trait_impl: false,
147 impl_lint_pass!(DocMarkdown => [DOC_MARKDOWN, MISSING_SAFETY_DOC, MISSING_ERRORS_DOC, NEEDLESS_DOCTEST_MAIN]);
149 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for DocMarkdown {
150 fn check_crate(&mut self, cx: &LateContext<'a, 'tcx>, krate: &'tcx hir::Crate<'_>) {
151 check_attrs(cx, &self.valid_idents, &krate.item.attrs);
154 fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::Item<'_>) {
155 let headers = check_attrs(cx, &self.valid_idents, &item.attrs);
157 hir::ItemKind::Fn(ref sig, _, body_id) => {
158 if !(is_entrypoint_fn(cx, cx.tcx.hir().local_def_id(item.hir_id).to_def_id())
159 || in_external_macro(cx.tcx.sess, item.span))
161 lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id));
164 hir::ItemKind::Impl {
165 of_trait: ref trait_ref,
168 self.in_trait_impl = trait_ref.is_some();
174 fn check_item_post(&mut self, _cx: &LateContext<'a, 'tcx>, item: &'tcx hir::Item<'_>) {
175 if let hir::ItemKind::Impl { .. } = item.kind {
176 self.in_trait_impl = false;
180 fn check_trait_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::TraitItem<'_>) {
181 let headers = check_attrs(cx, &self.valid_idents, &item.attrs);
182 if let hir::TraitItemKind::Fn(ref sig, ..) = item.kind {
183 if !in_external_macro(cx.tcx.sess, item.span) {
184 lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, None);
189 fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::ImplItem<'_>) {
190 let headers = check_attrs(cx, &self.valid_idents, &item.attrs);
191 if self.in_trait_impl || in_external_macro(cx.tcx.sess, item.span) {
194 if let hir::ImplItemKind::Fn(ref sig, body_id) = item.kind {
195 lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id));
200 fn lint_for_missing_headers<'a, 'tcx>(
201 cx: &LateContext<'a, 'tcx>,
203 span: impl Into<MultiSpan> + Copy,
204 sig: &hir::FnSig<'_>,
206 body_id: Option<hir::BodyId>,
208 if !cx.access_levels.is_exported(hir_id) {
209 return; // Private functions do not require doc comments
211 if !headers.safety && sig.header.unsafety == hir::Unsafety::Unsafe {
216 "unsafe function's docs miss `# Safety` section",
220 if is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym!(result_type)) {
225 "docs for function returning `Result` missing `# Errors` section",
229 if let Some(body_id) = body_id;
230 if let Some(future) = cx.tcx.lang_items().future_trait();
231 let def_id = cx.tcx.hir().body_owner_def_id(body_id);
232 let mir = cx.tcx.optimized_mir(def_id.to_def_id());
233 let ret_ty = mir.return_ty();
234 if implements_trait(cx, ret_ty, future, &[]);
235 if let ty::Opaque(_, subs) = ret_ty.kind;
236 if let Some(gen) = subs.types().next();
237 if let ty::Generator(_, subs, _) = gen.kind;
238 if is_type_diagnostic_item(cx, subs.as_generator().return_ty(), sym!(result_type));
244 "docs for function returning `Result` missing `# Errors` section",
252 /// Cleanup documentation decoration (`///` and such).
254 /// We can't use `rustc_ast::attr::AttributeMethods::with_desugared_doc` or
255 /// `rustc_ast::parse::lexer::comments::strip_doc_comment_decoration` because we
256 /// need to keep track of
257 /// the spans but this function is inspired from the later.
258 #[allow(clippy::cast_possible_truncation)]
260 pub fn strip_doc_comment_decoration(comment: &str, span: Span) -> (String, Vec<(usize, Span)>) {
261 // one-line comments lose their prefix
262 const ONELINERS: &[&str] = &["///!", "///", "//!", "//"];
263 for prefix in ONELINERS {
264 if comment.starts_with(*prefix) {
265 let doc = &comment[prefix.len()..];
266 let mut doc = doc.to_owned();
270 vec![(doc.len(), span.with_lo(span.lo() + BytePos(prefix.len() as u32)))],
275 if comment.starts_with("/*") {
276 let doc = &comment[3..comment.len() - 2];
277 let mut sizes = vec![];
278 let mut contains_initial_stars = false;
279 for line in doc.lines() {
280 let offset = line.as_ptr() as usize - comment.as_ptr() as usize;
281 debug_assert_eq!(offset as u32 as usize, offset);
282 contains_initial_stars |= line.trim_start().starts_with('*');
283 // +1 for the newline
284 sizes.push((line.len() + 1, span.with_lo(span.lo() + BytePos(offset as u32))));
286 if !contains_initial_stars {
287 return (doc.to_string(), sizes);
289 // remove the initial '*'s if any
290 let mut no_stars = String::with_capacity(doc.len());
291 for line in doc.lines() {
292 let mut chars = line.chars();
293 while let Some(c) = chars.next() {
294 if c.is_whitespace() {
297 no_stars.push(if c == '*' { ' ' } else { c });
301 no_stars.push_str(chars.as_str());
304 return (no_stars, sizes);
307 panic!("not a doc-comment: {}", comment);
310 #[derive(Copy, Clone)]
316 fn check_attrs<'a>(cx: &LateContext<'_, '_>, valid_idents: &FxHashSet<String>, attrs: &'a [Attribute]) -> DocHeaders {
317 let mut doc = String::new();
318 let mut spans = vec![];
321 if let AttrKind::DocComment(ref comment) = attr.kind {
322 let comment = comment.to_string();
323 let (comment, current_spans) = strip_doc_comment_decoration(&comment, attr.span);
324 spans.extend_from_slice(¤t_spans);
325 doc.push_str(&comment);
326 } else if attr.check_name(sym!(doc)) {
327 // ignore mix of sugared and non-sugared doc
328 // don't trigger the safety or errors check
337 for &mut (ref mut offset, _) in &mut spans {
338 let offset_copy = *offset;
340 current += offset_copy;
350 let parser = pulldown_cmark::Parser::new(&doc).into_offset_iter();
351 // Iterate over all `Events` and combine consecutive events into one
352 let events = parser.coalesce(|previous, current| {
353 use pulldown_cmark::Event::Text;
355 let previous_range = previous.1;
356 let current_range = current.1;
358 match (previous.0, current.0) {
359 (Text(previous), Text(current)) => {
360 let mut previous = previous.to_string();
361 previous.push_str(¤t);
362 Ok((Text(previous.into()), previous_range))
364 (previous, current) => Err(((previous, previous_range), (current, current_range))),
367 check_doc(cx, valid_idents, events, &spans)
370 const RUST_CODE: &[&str] = &["rust", "no_run", "should_panic", "compile_fail", "edition2018"];
372 fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize>)>>(
373 cx: &LateContext<'_, '_>,
374 valid_idents: &FxHashSet<String>,
376 spans: &[(usize, Span)],
378 // true if a safety header was found
379 use pulldown_cmark::CodeBlockKind;
380 use pulldown_cmark::Event::{
381 Code, End, FootnoteReference, HardBreak, Html, Rule, SoftBreak, Start, TaskListMarker, Text,
383 use pulldown_cmark::Tag::{CodeBlock, Heading, Link};
385 let mut headers = DocHeaders {
389 let mut in_code = false;
390 let mut in_link = None;
391 let mut in_heading = false;
392 let mut is_rust = false;
393 for (event, range) in events {
395 Start(CodeBlock(ref kind)) => {
397 if let CodeBlockKind::Fenced(lang) = kind {
399 lang.is_empty() || !lang.contains("ignore") && lang.split(',').any(|i| RUST_CODE.contains(&i));
402 End(CodeBlock(_)) => {
406 Start(Link(_, url, _)) => in_link = Some(url),
407 End(Link(..)) => in_link = None,
408 Start(Heading(_)) => in_heading = true,
409 End(Heading(_)) => in_heading = false,
410 Start(_tag) | End(_tag) => (), // We don't care about other tags
411 Html(_html) => (), // HTML is weird, just ignore it
412 SoftBreak | HardBreak | TaskListMarker(_) | Code(_) | Rule => (),
413 FootnoteReference(text) | Text(text) => {
414 if Some(&text) == in_link.as_ref() {
415 // Probably a link of the form `<http://example.com>`
416 // Which are represented as a link to "http://example.com" with
417 // text "http://example.com" by pulldown-cmark
420 headers.safety |= in_heading && text.trim() == "Safety";
421 headers.errors |= in_heading && text.trim() == "Errors";
422 let index = match spans.binary_search_by(|c| c.0.cmp(&range.start)) {
426 let (begin, span) = spans[index];
429 check_code(cx, &text, span);
432 // Adjust for the beginning of the current `Event`
433 let span = span.with_lo(span.lo() + BytePos::from_usize(range.start - begin));
435 check_text(cx, valid_idents, &text, span);
443 static LEAVE_MAIN_PATTERNS: &[&str] = &["static", "fn main() {}", "extern crate", "async fn main() {"];
445 fn check_code(cx: &LateContext<'_, '_>, text: &str, span: Span) {
446 if text.contains("fn main() {") && !LEAVE_MAIN_PATTERNS.iter().any(|p| text.contains(p)) {
447 span_lint(cx, NEEDLESS_DOCTEST_MAIN, span, "needless `fn main` in doctest");
451 fn check_text(cx: &LateContext<'_, '_>, valid_idents: &FxHashSet<String>, text: &str, span: Span) {
452 for word in text.split(|c: char| c.is_whitespace() || c == '\'') {
453 // Trim punctuation as in `some comment (see foo::bar).`
455 // Or even as in `_foo bar_` which is emphasized.
456 let word = word.trim_matches(|c: char| !c.is_alphanumeric());
458 if valid_idents.contains(word) {
462 // Adjust for the current word
463 let offset = word.as_ptr() as usize - text.as_ptr() as usize;
464 let span = Span::new(
465 span.lo() + BytePos::from_usize(offset),
466 span.lo() + BytePos::from_usize(offset + word.len()),
470 check_word(cx, word, span);
474 fn check_word(cx: &LateContext<'_, '_>, word: &str, span: Span) {
475 /// Checks if a string is camel-case, i.e., contains at least two uppercase
476 /// letters (`Clippy` is ok) and one lower-case letter (`NASA` is ok).
477 /// Plurals are also excluded (`IDs` is ok).
478 fn is_camel_case(s: &str) -> bool {
479 if s.starts_with(|c: char| c.is_digit(10)) {
483 let s = if s.ends_with('s') { &s[..s.len() - 1] } else { s };
485 s.chars().all(char::is_alphanumeric)
486 && s.chars().filter(|&c| c.is_uppercase()).take(2).count() > 1
487 && s.chars().filter(|&c| c.is_lowercase()).take(1).count() > 0
490 fn has_underscore(s: &str) -> bool {
491 s != "_" && !s.contains("\\_") && s.contains('_')
494 fn has_hyphen(s: &str) -> bool {
495 s != "-" && s.contains('-')
498 if let Ok(url) = Url::parse(word) {
499 // try to get around the fact that `foo::bar` parses as a valid URL
500 if !url.cannot_be_a_base() {
505 "you should put bare URLs between `<`/`>` or make a proper Markdown link",
512 // We assume that mixed-case words are not meant to be put inside bacticks. (Issue #2343)
513 if has_underscore(word) && has_hyphen(word) {
517 if has_underscore(word) || word.contains("::") || is_camel_case(word) {
522 &format!("you should put `{}` between ticks in the documentation", word),