1 //! Validates syntax inside Rust code blocks (\`\`\`rust).
2 use rustc_data_structures::sync::{Lock, Lrc};
5 translation::{to_fluent_args, Translate},
6 Applicability, Diagnostic, Handler, LazyFallbackBundle,
8 use rustc_parse::parse_stream_from_source_str;
9 use rustc_session::parse::ParseSess;
10 use rustc_span::hygiene::{AstPass, ExpnData, ExpnKind, LocalExpnId};
11 use rustc_span::source_map::{FilePathMapping, SourceMap};
12 use rustc_span::{FileName, InnerSpan, DUMMY_SP};
15 use crate::core::DocContext;
16 use crate::html::markdown::{self, RustCodeBlock};
17 use crate::passes::Pass;
18 use crate::visit::DocVisitor;
20 pub(crate) const CHECK_CODE_BLOCK_SYNTAX: Pass = Pass {
21 name: "check-code-block-syntax",
22 run: check_code_block_syntax,
23 description: "validates syntax inside Rust code blocks",
26 pub(crate) fn check_code_block_syntax(
28 cx: &mut DocContext<'_>,
30 SyntaxChecker { cx }.visit_crate(&krate);
34 struct SyntaxChecker<'a, 'tcx> {
35 cx: &'a DocContext<'tcx>,
38 impl<'a, 'tcx> SyntaxChecker<'a, 'tcx> {
39 fn check_rust_syntax(&self, item: &clean::Item, dox: &str, code_block: RustCodeBlock) {
40 let buffer = Lrc::new(Lock::new(Buffer::default()));
42 rustc_errors::fallback_fluent_bundle(rustc_errors::DEFAULT_LOCALE_RESOURCES, false);
43 let emitter = BufferEmitter { buffer: Lrc::clone(&buffer), fallback_bundle };
45 let sm = Lrc::new(SourceMap::new(FilePathMapping::empty()));
46 let handler = Handler::with_emitter(false, None, Box::new(emitter));
47 let source = dox[code_block.code].to_owned();
48 let sess = ParseSess::with_span_handler(handler, sm);
50 let edition = code_block.lang_string.edition.unwrap_or_else(|| self.cx.tcx.sess.edition());
51 let expn_data = ExpnData::default(
52 ExpnKind::AstPass(AstPass::TestHarness),
59 self.cx.tcx.with_stable_hashing_context(|hcx| LocalExpnId::fresh(expn_data, hcx));
60 let span = DUMMY_SP.fresh_expansion(expn_id);
62 let is_empty = rustc_driver::catch_fatal_errors(|| {
63 parse_stream_from_source_str(
64 FileName::Custom(String::from("doctest")),
72 let buffer = buffer.borrow();
74 if !buffer.has_errors && !is_empty {
75 // No errors in a non-empty program.
79 let Some(local_id) = item.item_id.as_def_id().and_then(|x| x.as_local())
81 // We don't need to check the syntax for other crates so returning
82 // without doing anything should not be a problem.
86 let hir_id = self.cx.tcx.hir().local_def_id_to_hir_id(local_id);
87 let empty_block = code_block.lang_string == Default::default() && code_block.is_fenced;
88 let is_ignore = code_block.lang_string.ignore != markdown::Ignore::None;
90 // The span and whether it is precise or not.
91 let (sp, precise_span) = match super::source_span_for_markdown_range(
97 Some(sp) => (sp, true),
98 None => (item.attr_span(self.cx.tcx), false),
101 let msg = if buffer.has_errors {
102 "could not parse code block as Rust code"
104 "Rust code block is empty"
107 // Finally build and emit the completed diagnostic.
108 // All points of divergence have been handled earlier so this can be
109 // done the same way whether the span is precise or not.
110 self.cx.tcx.struct_span_lint_hir(
111 crate::lint::INVALID_RUST_CODEBLOCKS,
116 let explanation = if is_ignore {
117 "`ignore` code blocks require valid Rust code for syntax highlighting; \
118 mark blocks that do not contain Rust code as text"
120 "mark blocks that do not contain Rust code as text"
125 // giving an accurate suggestion is hard because `ignore` might not have come first in the list.
126 // just give a `help` instead.
128 sp.from_inner(InnerSpan::new(0, 3)),
129 &format!("{}: ```text", explanation),
131 } else if empty_block {
132 lint.span_suggestion(
133 sp.from_inner(InnerSpan::new(0, 3)).shrink_to_hi(),
136 Applicability::MachineApplicable,
139 } else if empty_block || is_ignore {
140 lint.help(&format!("{}: ```text", explanation));
143 // FIXME(#67563): Provide more context for these errors by displaying the spans inline.
144 for message in buffer.messages.iter() {
154 impl<'a, 'tcx> DocVisitor for SyntaxChecker<'a, 'tcx> {
155 fn visit_item(&mut self, item: &clean::Item) {
156 if let Some(dox) = &item.attrs.collapsed_doc_value() {
157 let sp = item.attr_span(self.cx.tcx);
158 let extra = crate::html::markdown::ExtraInfo::new_did(
160 item.item_id.expect_def_id(),
163 for code_block in markdown::rust_code_blocks(dox, &extra) {
164 self.check_rust_syntax(item, dox, code_block);
168 self.visit_item_recur(item)
174 messages: Vec<String>,
178 struct BufferEmitter {
179 buffer: Lrc<Lock<Buffer>>,
180 fallback_bundle: LazyFallbackBundle,
183 impl Translate for BufferEmitter {
184 fn fluent_bundle(&self) -> Option<&Lrc<rustc_errors::FluentBundle>> {
188 fn fallback_fluent_bundle(&self) -> &rustc_errors::FluentBundle {
189 &**self.fallback_bundle
193 impl Emitter for BufferEmitter {
194 fn emit_diagnostic(&mut self, diag: &Diagnostic) {
195 let mut buffer = self.buffer.borrow_mut();
197 let fluent_args = to_fluent_args(diag.args());
198 let translated_main_message = self.translate_message(&diag.message[0].0, &fluent_args);
200 buffer.messages.push(format!("error from rustc: {}", translated_main_message));
202 buffer.has_errors = true;
206 fn source_map(&self) -> Option<&Lrc<SourceMap>> {