593 lines
21 KiB
Rust
593 lines
21 KiB
Rust
use crate::utils::{implements_trait, is_entrypoint_fn, is_type_diagnostic_item, return_ty, span_lint};
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use if_chain::if_chain;
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use itertools::Itertools;
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use rustc_ast::ast::{Async, AttrKind, Attribute, FnRetTy, ItemKind};
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use rustc_ast::token::CommentKind;
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use rustc_data_structures::fx::FxHashSet;
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use rustc_data_structures::sync::Lrc;
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use rustc_errors::emitter::EmitterWriter;
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use rustc_errors::Handler;
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use rustc_hir as hir;
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_middle::lint::in_external_macro;
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use rustc_middle::ty;
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use rustc_parse::maybe_new_parser_from_source_str;
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use rustc_session::parse::ParseSess;
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use rustc_session::{declare_tool_lint, impl_lint_pass};
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use rustc_span::source_map::{BytePos, FilePathMapping, MultiSpan, SourceMap, Span};
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use rustc_span::{sym, FileName, Pos};
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use std::io;
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use std::ops::Range;
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use url::Url;
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declare_clippy_lint! {
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/// **What it does:** Checks for the presence of `_`, `::` or camel-case words
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/// outside ticks in documentation.
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///
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/// **Why is this bad?** *Rustdoc* supports markdown formatting, `_`, `::` and
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/// camel-case probably indicates some code which should be included between
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/// ticks. `_` can also be used for emphasis in markdown, this lint tries to
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/// consider that.
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///
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/// **Known problems:** Lots of bad docs won’t be fixed, what the lint checks
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/// for is limited, and there are still false positives.
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///
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/// In addition, when writing documentation comments, including `[]` brackets
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/// inside a link text would trip the parser. Therfore, documenting link with
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/// `[`SmallVec<[T; INLINE_CAPACITY]>`]` and then [`SmallVec<[T; INLINE_CAPACITY]>`]: SmallVec
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/// would fail.
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///
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/// **Examples:**
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/// ```rust
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/// /// Do something with the foo_bar parameter. See also
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/// /// that::other::module::foo.
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/// // ^ `foo_bar` and `that::other::module::foo` should be ticked.
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/// fn doit(foo_bar: usize) {}
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/// ```
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///
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/// ```rust
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/// // Link text with `[]` brackets should be written as following:
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/// /// Consume the array and return the inner
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/// /// [`SmallVec<[T; INLINE_CAPACITY]>`][SmallVec].
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/// /// [SmallVec]: SmallVec
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/// fn main() {}
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/// ```
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pub DOC_MARKDOWN,
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pedantic,
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"presence of `_`, `::` or camel-case outside backticks in documentation"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for the doc comments of publicly visible
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/// unsafe functions and warns if there is no `# Safety` section.
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///
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/// **Why is this bad?** Unsafe functions should document their safety
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/// preconditions, so that users can be sure they are using them safely.
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///
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/// **Known problems:** None.
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///
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/// **Examples:**
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/// ```rust
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///# type Universe = ();
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/// /// This function should really be documented
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/// pub unsafe fn start_apocalypse(u: &mut Universe) {
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/// unimplemented!();
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/// }
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/// ```
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///
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/// At least write a line about safety:
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///
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/// ```rust
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///# type Universe = ();
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/// /// # Safety
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/// ///
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/// /// This function should not be called before the horsemen are ready.
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/// pub unsafe fn start_apocalypse(u: &mut Universe) {
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/// unimplemented!();
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/// }
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/// ```
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pub MISSING_SAFETY_DOC,
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style,
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"`pub unsafe fn` without `# Safety` docs"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks the doc comments of publicly visible functions that
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/// return a `Result` type and warns if there is no `# Errors` section.
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///
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/// **Why is this bad?** Documenting the type of errors that can be returned from a
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/// function can help callers write code to handle the errors appropriately.
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///
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/// **Known problems:** None.
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///
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/// **Examples:**
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///
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/// Since the following function returns a `Result` it has an `# Errors` section in
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/// its doc comment:
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///
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/// ```rust
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///# use std::io;
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/// /// # Errors
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/// ///
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/// /// Will return `Err` if `filename` does not exist or the user does not have
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/// /// permission to read it.
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/// pub fn read(filename: String) -> io::Result<String> {
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/// unimplemented!();
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/// }
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/// ```
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pub MISSING_ERRORS_DOC,
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pedantic,
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"`pub fn` returns `Result` without `# Errors` in doc comment"
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}
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declare_clippy_lint! {
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/// **What it does:** Checks for `fn main() { .. }` in doctests
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///
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/// **Why is this bad?** The test can be shorter (and likely more readable)
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/// if the `fn main()` is left implicit.
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///
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/// **Known problems:** None.
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///
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/// **Examples:**
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/// ``````rust
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/// /// An example of a doctest with a `main()` function
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/// ///
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/// /// # Examples
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/// ///
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/// /// ```
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/// /// fn main() {
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/// /// // this needs not be in an `fn`
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/// /// }
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/// /// ```
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/// fn needless_main() {
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/// unimplemented!();
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/// }
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/// ``````
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pub NEEDLESS_DOCTEST_MAIN,
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style,
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"presence of `fn main() {` in code examples"
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}
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#[allow(clippy::module_name_repetitions)]
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#[derive(Clone)]
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pub struct DocMarkdown {
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valid_idents: FxHashSet<String>,
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in_trait_impl: bool,
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}
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impl DocMarkdown {
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pub fn new(valid_idents: FxHashSet<String>) -> Self {
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Self {
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valid_idents,
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in_trait_impl: false,
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}
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}
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}
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impl_lint_pass!(DocMarkdown => [DOC_MARKDOWN, MISSING_SAFETY_DOC, MISSING_ERRORS_DOC, NEEDLESS_DOCTEST_MAIN]);
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impl<'tcx> LateLintPass<'tcx> for DocMarkdown {
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fn check_crate(&mut self, cx: &LateContext<'tcx>, krate: &'tcx hir::Crate<'_>) {
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check_attrs(cx, &self.valid_idents, &krate.item.attrs);
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}
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fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) {
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let headers = check_attrs(cx, &self.valid_idents, &item.attrs);
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match item.kind {
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hir::ItemKind::Fn(ref sig, _, body_id) => {
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if !(is_entrypoint_fn(cx, cx.tcx.hir().local_def_id(item.hir_id).to_def_id())
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|| in_external_macro(cx.tcx.sess, item.span))
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{
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lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id));
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}
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},
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hir::ItemKind::Impl {
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of_trait: ref trait_ref,
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..
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} => {
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self.in_trait_impl = trait_ref.is_some();
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},
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_ => {},
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}
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}
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fn check_item_post(&mut self, _cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) {
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if let hir::ItemKind::Impl { .. } = item.kind {
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self.in_trait_impl = false;
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}
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}
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fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::TraitItem<'_>) {
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let headers = check_attrs(cx, &self.valid_idents, &item.attrs);
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if let hir::TraitItemKind::Fn(ref sig, ..) = item.kind {
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if !in_external_macro(cx.tcx.sess, item.span) {
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lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, None);
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}
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}
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}
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fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::ImplItem<'_>) {
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let headers = check_attrs(cx, &self.valid_idents, &item.attrs);
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if self.in_trait_impl || in_external_macro(cx.tcx.sess, item.span) {
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return;
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}
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if let hir::ImplItemKind::Fn(ref sig, body_id) = item.kind {
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lint_for_missing_headers(cx, item.hir_id, item.span, sig, headers, Some(body_id));
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}
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}
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}
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fn lint_for_missing_headers<'tcx>(
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cx: &LateContext<'tcx>,
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hir_id: hir::HirId,
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span: impl Into<MultiSpan> + Copy,
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sig: &hir::FnSig<'_>,
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headers: DocHeaders,
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body_id: Option<hir::BodyId>,
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) {
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if !cx.access_levels.is_exported(hir_id) {
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return; // Private functions do not require doc comments
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}
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if !headers.safety && sig.header.unsafety == hir::Unsafety::Unsafe {
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span_lint(
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cx,
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MISSING_SAFETY_DOC,
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span,
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"unsafe function's docs miss `# Safety` section",
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);
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}
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if !headers.errors {
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if is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym::result_type) {
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span_lint(
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cx,
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MISSING_ERRORS_DOC,
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span,
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"docs for function returning `Result` missing `# Errors` section",
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);
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} else {
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if_chain! {
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if let Some(body_id) = body_id;
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if let Some(future) = cx.tcx.lang_items().future_trait();
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let def_id = cx.tcx.hir().body_owner_def_id(body_id);
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let mir = cx.tcx.optimized_mir(def_id.to_def_id());
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let ret_ty = mir.return_ty();
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if implements_trait(cx, ret_ty, future, &[]);
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if let ty::Opaque(_, subs) = ret_ty.kind();
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if let Some(gen) = subs.types().next();
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if let ty::Generator(_, subs, _) = gen.kind();
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if is_type_diagnostic_item(cx, subs.as_generator().return_ty(), sym::result_type);
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then {
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span_lint(
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cx,
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MISSING_ERRORS_DOC,
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span,
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"docs for function returning `Result` missing `# Errors` section",
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);
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}
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}
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}
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}
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}
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/// Cleanup documentation decoration.
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///
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/// We can't use `rustc_ast::attr::AttributeMethods::with_desugared_doc` or
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/// `rustc_ast::parse::lexer::comments::strip_doc_comment_decoration` because we
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/// need to keep track of
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/// the spans but this function is inspired from the later.
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#[allow(clippy::cast_possible_truncation)]
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#[must_use]
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pub fn strip_doc_comment_decoration(doc: &str, comment_kind: CommentKind, span: Span) -> (String, Vec<(usize, Span)>) {
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// one-line comments lose their prefix
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if comment_kind == CommentKind::Line {
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let mut doc = doc.to_owned();
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doc.push('\n');
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let len = doc.len();
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// +3 skips the opening delimiter
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return (doc, vec![(len, span.with_lo(span.lo() + BytePos(3)))]);
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}
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let mut sizes = vec![];
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let mut contains_initial_stars = false;
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for line in doc.lines() {
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let offset = line.as_ptr() as usize - doc.as_ptr() as usize;
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debug_assert_eq!(offset as u32 as usize, offset);
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contains_initial_stars |= line.trim_start().starts_with('*');
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// +1 adds the newline, +3 skips the opening delimiter
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sizes.push((line.len() + 1, span.with_lo(span.lo() + BytePos(3 + offset as u32))));
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}
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if !contains_initial_stars {
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return (doc.to_string(), sizes);
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}
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// remove the initial '*'s if any
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let mut no_stars = String::with_capacity(doc.len());
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for line in doc.lines() {
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let mut chars = line.chars();
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while let Some(c) = chars.next() {
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if c.is_whitespace() {
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no_stars.push(c);
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} else {
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no_stars.push(if c == '*' { ' ' } else { c });
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break;
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}
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}
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no_stars.push_str(chars.as_str());
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no_stars.push('\n');
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}
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(no_stars, sizes)
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}
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#[derive(Copy, Clone)]
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struct DocHeaders {
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safety: bool,
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errors: bool,
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}
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fn check_attrs<'a>(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, attrs: &'a [Attribute]) -> DocHeaders {
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let mut doc = String::new();
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let mut spans = vec![];
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for attr in attrs {
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if let AttrKind::DocComment(comment_kind, comment) = attr.kind {
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let (comment, current_spans) = strip_doc_comment_decoration(&comment.as_str(), comment_kind, attr.span);
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spans.extend_from_slice(¤t_spans);
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doc.push_str(&comment);
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} else if attr.has_name(sym::doc) {
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// ignore mix of sugared and non-sugared doc
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// don't trigger the safety or errors check
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return DocHeaders {
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safety: true,
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errors: true,
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};
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}
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}
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let mut current = 0;
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for &mut (ref mut offset, _) in &mut spans {
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let offset_copy = *offset;
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*offset = current;
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current += offset_copy;
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}
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if doc.is_empty() {
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return DocHeaders {
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safety: false,
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errors: false,
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};
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}
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let parser = pulldown_cmark::Parser::new(&doc).into_offset_iter();
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// Iterate over all `Events` and combine consecutive events into one
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let events = parser.coalesce(|previous, current| {
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use pulldown_cmark::Event::Text;
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let previous_range = previous.1;
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let current_range = current.1;
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match (previous.0, current.0) {
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(Text(previous), Text(current)) => {
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let mut previous = previous.to_string();
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previous.push_str(¤t);
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Ok((Text(previous.into()), previous_range))
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},
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(previous, current) => Err(((previous, previous_range), (current, current_range))),
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}
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});
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check_doc(cx, valid_idents, events, &spans)
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}
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const RUST_CODE: &[&str] = &["rust", "no_run", "should_panic", "compile_fail", "edition2018"];
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fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize>)>>(
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cx: &LateContext<'_>,
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valid_idents: &FxHashSet<String>,
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events: Events,
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spans: &[(usize, Span)],
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) -> DocHeaders {
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// true if a safety header was found
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use pulldown_cmark::CodeBlockKind;
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use pulldown_cmark::Event::{
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Code, End, FootnoteReference, HardBreak, Html, Rule, SoftBreak, Start, TaskListMarker, Text,
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};
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use pulldown_cmark::Tag::{CodeBlock, Heading, Link};
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let mut headers = DocHeaders {
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safety: false,
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errors: false,
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};
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let mut in_code = false;
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let mut in_link = None;
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let mut in_heading = false;
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let mut is_rust = false;
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for (event, range) in events {
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match event {
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Start(CodeBlock(ref kind)) => {
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in_code = true;
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if let CodeBlockKind::Fenced(lang) = kind {
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is_rust =
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lang.is_empty() || !lang.contains("ignore") && lang.split(',').any(|i| RUST_CODE.contains(&i));
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}
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},
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End(CodeBlock(_)) => {
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in_code = false;
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is_rust = false;
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},
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Start(Link(_, url, _)) => in_link = Some(url),
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End(Link(..)) => in_link = None,
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Start(Heading(_)) => in_heading = true,
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End(Heading(_)) => in_heading = false,
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Start(_tag) | End(_tag) => (), // We don't care about other tags
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Html(_html) => (), // HTML is weird, just ignore it
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SoftBreak | HardBreak | TaskListMarker(_) | Code(_) | Rule => (),
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FootnoteReference(text) | Text(text) => {
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if Some(&text) == in_link.as_ref() {
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// Probably a link of the form `<http://example.com>`
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// Which are represented as a link to "http://example.com" with
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// text "http://example.com" by pulldown-cmark
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continue;
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}
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headers.safety |= in_heading && text.trim() == "Safety";
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headers.errors |= in_heading && text.trim() == "Errors";
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let index = match spans.binary_search_by(|c| c.0.cmp(&range.start)) {
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Ok(o) => o,
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Err(e) => e - 1,
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};
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let (begin, span) = spans[index];
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if in_code {
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if is_rust {
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check_code(cx, &text, span);
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}
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} else {
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// Adjust for the beginning of the current `Event`
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let span = span.with_lo(span.lo() + BytePos::from_usize(range.start - begin));
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check_text(cx, valid_idents, &text, span);
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}
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},
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}
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}
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headers
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}
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fn check_code(cx: &LateContext<'_>, text: &str, span: Span) {
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fn has_needless_main(code: &str) -> bool {
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let filename = FileName::anon_source_code(code);
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let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
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let emitter = EmitterWriter::new(box io::sink(), None, false, false, false, None, false);
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let handler = Handler::with_emitter(false, None, box emitter);
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let sess = ParseSess::with_span_handler(handler, sm);
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let mut parser = match maybe_new_parser_from_source_str(&sess, filename, code.into()) {
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Ok(p) => p,
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Err(errs) => {
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for mut err in errs {
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err.cancel();
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}
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return false;
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},
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};
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let mut relevant_main_found = false;
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loop {
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match parser.parse_item() {
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Ok(Some(item)) => match &item.kind {
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// Tests with one of these items are ignored
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ItemKind::Static(..)
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| ItemKind::Const(..)
|
||
| ItemKind::ExternCrate(..)
|
||
| ItemKind::ForeignMod(..) => return false,
|
||
// We found a main function ...
|
||
ItemKind::Fn(_, sig, _, Some(block)) if item.ident.name == sym::main => {
|
||
let is_async = matches!(sig.header.asyncness, Async::Yes{..});
|
||
let returns_nothing = match &sig.decl.output {
|
||
FnRetTy::Default(..) => true,
|
||
FnRetTy::Ty(ty) if ty.kind.is_unit() => true,
|
||
_ => false,
|
||
};
|
||
|
||
if returns_nothing && !is_async && !block.stmts.is_empty() {
|
||
// This main function should be linted, but only if there are no other functions
|
||
relevant_main_found = true;
|
||
} else {
|
||
// This main function should not be linted, we're done
|
||
return false;
|
||
}
|
||
},
|
||
// Another function was found; this case is ignored too
|
||
ItemKind::Fn(..) => return false,
|
||
_ => {},
|
||
},
|
||
Ok(None) => break,
|
||
Err(mut e) => {
|
||
e.cancel();
|
||
return false;
|
||
},
|
||
}
|
||
}
|
||
|
||
relevant_main_found
|
||
}
|
||
|
||
if has_needless_main(text) {
|
||
span_lint(cx, NEEDLESS_DOCTEST_MAIN, span, "needless `fn main` in doctest");
|
||
}
|
||
}
|
||
|
||
fn check_text(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, text: &str, span: Span) {
|
||
for word in text.split(|c: char| c.is_whitespace() || c == '\'') {
|
||
// Trim punctuation as in `some comment (see foo::bar).`
|
||
// ^^
|
||
// Or even as in `_foo bar_` which is emphasized.
|
||
let word = word.trim_matches(|c: char| !c.is_alphanumeric());
|
||
|
||
if valid_idents.contains(word) {
|
||
continue;
|
||
}
|
||
|
||
// Adjust for the current word
|
||
let offset = word.as_ptr() as usize - text.as_ptr() as usize;
|
||
let span = Span::new(
|
||
span.lo() + BytePos::from_usize(offset),
|
||
span.lo() + BytePos::from_usize(offset + word.len()),
|
||
span.ctxt(),
|
||
);
|
||
|
||
check_word(cx, word, span);
|
||
}
|
||
}
|
||
|
||
fn check_word(cx: &LateContext<'_>, word: &str, span: Span) {
|
||
/// Checks if a string is camel-case, i.e., contains at least two uppercase
|
||
/// letters (`Clippy` is ok) and one lower-case letter (`NASA` is ok).
|
||
/// Plurals are also excluded (`IDs` is ok).
|
||
fn is_camel_case(s: &str) -> bool {
|
||
if s.starts_with(|c: char| c.is_digit(10)) {
|
||
return false;
|
||
}
|
||
|
||
let s = s.strip_suffix('s').unwrap_or(s);
|
||
|
||
s.chars().all(char::is_alphanumeric)
|
||
&& s.chars().filter(|&c| c.is_uppercase()).take(2).count() > 1
|
||
&& s.chars().filter(|&c| c.is_lowercase()).take(1).count() > 0
|
||
}
|
||
|
||
fn has_underscore(s: &str) -> bool {
|
||
s != "_" && !s.contains("\\_") && s.contains('_')
|
||
}
|
||
|
||
fn has_hyphen(s: &str) -> bool {
|
||
s != "-" && s.contains('-')
|
||
}
|
||
|
||
if let Ok(url) = Url::parse(word) {
|
||
// try to get around the fact that `foo::bar` parses as a valid URL
|
||
if !url.cannot_be_a_base() {
|
||
span_lint(
|
||
cx,
|
||
DOC_MARKDOWN,
|
||
span,
|
||
"you should put bare URLs between `<`/`>` or make a proper Markdown link",
|
||
);
|
||
|
||
return;
|
||
}
|
||
}
|
||
|
||
// We assume that mixed-case words are not meant to be put inside bacticks. (Issue #2343)
|
||
if has_underscore(word) && has_hyphen(word) {
|
||
return;
|
||
}
|
||
|
||
if has_underscore(word) || word.contains("::") || is_camel_case(word) {
|
||
span_lint(
|
||
cx,
|
||
DOC_MARKDOWN,
|
||
span,
|
||
&format!("you should put `{}` between ticks in the documentation", word),
|
||
);
|
||
}
|
||
}
|