diff --git a/compiler/rustc_mir/src/borrow_check/region_infer/mod.rs b/compiler/rustc_mir/src/borrow_check/region_infer/mod.rs index bbd512fd360..9dc2e3d2923 100644 --- a/compiler/rustc_mir/src/borrow_check/region_infer/mod.rs +++ b/compiler/rustc_mir/src/borrow_check/region_infer/mod.rs @@ -1241,7 +1241,7 @@ impl<'tcx> RegionInferenceContext<'tcx> { /// it. However, it works pretty well in practice. In particular, /// this is needed to deal with projection outlives bounds like /// - /// ```ignore (internal compiler representation so lifetime syntax is invalid) + /// ```text (internal compiler representation so lifetime syntax is invalid) /// >::Item: '1 /// ``` /// diff --git a/compiler/rustc_trait_selection/src/opaque_types.rs b/compiler/rustc_trait_selection/src/opaque_types.rs index fb4a8ce687c..7e67bc118ec 100644 --- a/compiler/rustc_trait_selection/src/opaque_types.rs +++ b/compiler/rustc_trait_selection/src/opaque_types.rs @@ -46,6 +46,7 @@ pub struct OpaqueTypeDecl<'tcx> { /// type Foo = impl Baz; /// fn bar() -> Foo { /// // ^^^ This is the span we are looking for! + /// } /// ``` /// /// In cases where the fn returns `(impl Trait, impl Trait)` or diff --git a/compiler/rustc_typeck/src/check/upvar.rs b/compiler/rustc_typeck/src/check/upvar.rs index ff506ef8727..71e222c560a 100644 --- a/compiler/rustc_typeck/src/check/upvar.rs +++ b/compiler/rustc_typeck/src/check/upvar.rs @@ -323,7 +323,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { /// /// InferBorrowKind results in a structure like this: /// - /// ``` + /// ```text /// { /// Place(base: hir_id_s, projections: [], ....) -> { /// capture_kind_expr: hir_id_L5, @@ -348,7 +348,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { /// ``` /// /// After the min capture analysis, we get: - /// ``` + /// ```text /// { /// hir_id_s -> [ /// Place(base: hir_id_s, projections: [], ....) -> { diff --git a/src/doc/rustdoc/src/lints.md b/src/doc/rustdoc/src/lints.md index a6626679a7d..7088e60aa07 100644 --- a/src/doc/rustdoc/src/lints.md +++ b/src/doc/rustdoc/src/lints.md @@ -294,6 +294,43 @@ warning: unclosed HTML tag `h1` warning: 2 warnings emitted ``` +## invalid_rust_codeblock + +This lint **warns by default**. It detects Rust code blocks in documentation +examples that are invalid (e.g. empty, not parsable as Rust). For example: + +```rust +/// Empty code blocks (with and without the `rust` marker): +/// +/// ```rust +/// ``` +/// +/// Unclosed code blocks (with and without the `rust` marker): +/// +/// ```rust +fn main() {} +``` + +Which will give: + +```text +warning: Rust code block is empty +--> src/lib.rs:3:5 +| +3 | /// ```rust +| _____^ +4 | | /// ``` +| |_______^ +| += note: `#[warn(rustdoc::invalid_rust_codeblock)]` on by default + +warning: Rust code block is empty +--> src/lib.rs:8:5 +| +8 | /// ```rust +| ^^^^^^^ +``` + ## bare_urls This lint is **warn-by-default**. It detects URLs which are not links. diff --git a/src/librustdoc/lint.rs b/src/librustdoc/lint.rs index 1b79811d4b0..597efed56e1 100644 --- a/src/librustdoc/lint.rs +++ b/src/librustdoc/lint.rs @@ -157,6 +157,18 @@ declare_rustdoc_lint! { "detects URLs that are not hyperlinks" } +declare_rustdoc_lint! { + /// The `invalid_rust_codeblock` lint detects Rust code blocks in + /// documentation examples that are invalid (e.g. empty, not parsable as + /// Rust code). This is a `rustdoc` only lint, see the documentation in the + /// [rustdoc book]. + /// + /// [rustdoc book]: ../../../rustdoc/lints.html#invalid_rust_codeblock + INVALID_RUST_CODEBLOCK, + Warn, + "codeblock could not be parsed as valid Rust or is empty" +} + crate static RUSTDOC_LINTS: Lazy> = Lazy::new(|| { vec![ BROKEN_INTRA_DOC_LINKS, @@ -164,6 +176,7 @@ crate static RUSTDOC_LINTS: Lazy> = Lazy::new(|| { MISSING_DOC_CODE_EXAMPLES, PRIVATE_DOC_TESTS, INVALID_CODEBLOCK_ATTRIBUTES, + INVALID_RUST_CODEBLOCK, INVALID_HTML_TAGS, BARE_URLS, MISSING_CRATE_LEVEL_DOCS, diff --git a/src/librustdoc/passes/check_code_block_syntax.rs b/src/librustdoc/passes/check_code_block_syntax.rs index 8d07cde5188..293941391c8 100644 --- a/src/librustdoc/passes/check_code_block_syntax.rs +++ b/src/librustdoc/passes/check_code_block_syntax.rs @@ -1,5 +1,6 @@ use rustc_data_structures::sync::{Lock, Lrc}; use rustc_errors::{emitter::Emitter, Applicability, Diagnostic, Handler}; +use rustc_middle::lint::LintDiagnosticBuilder; use rustc_parse::parse_stream_from_source_str; use rustc_session::parse::ParseSess; use rustc_span::source_map::{FilePathMapping, SourceMap}; @@ -47,50 +48,65 @@ impl<'a, 'tcx> SyntaxChecker<'a, 'tcx> { .unwrap_or(false); let buffer = buffer.borrow(); - if buffer.has_errors || is_empty { - let mut diag = if let Some(sp) = super::source_span_for_markdown_range( - self.cx.tcx, - &dox, - &code_block.range, - &item.attrs, - ) { - let (warning_message, suggest_using_text) = if buffer.has_errors { - ("could not parse code block as Rust code", true) + if !(buffer.has_errors || is_empty) { + // No errors in a non-empty program. + return; + } + + let local_id = match item.def_id.as_local() { + Some(id) => id, + // We don't need to check the syntax for other crates so returning + // without doing anything should not be a problem. + None => return, + }; + + let hir_id = self.cx.tcx.hir().local_def_id_to_hir_id(local_id); + let suggest_using_text = code_block.syntax.is_none() && code_block.is_fenced; + let is_ignore = code_block.is_ignore; + + // The span and whether it is precise or not. + let (sp, precise_span) = match super::source_span_for_markdown_range( + self.cx.tcx, + &dox, + &code_block.range, + &item.attrs, + ) { + Some(sp) => (sp, true), + None => (item.attr_span(self.cx.tcx), false), + }; + + // lambda that will use the lint to start a new diagnostic and add + // a suggestion to it when needed. + let diag_builder = |lint: LintDiagnosticBuilder<'_>| { + let mut diag = if precise_span { + let msg = if buffer.has_errors { + "could not parse code block as Rust code" } else { - ("Rust code block is empty", false) + "Rust code block is empty" }; - let mut diag = self.cx.sess().struct_span_warn(sp, warning_message); + let mut diag = lint.build(msg); - if code_block.syntax.is_none() && code_block.is_fenced { - let sp = sp.from_inner(InnerSpan::new(0, 3)); - diag.span_suggestion( - sp, - "mark blocks that do not contain Rust code as text", - String::from("```text"), - Applicability::MachineApplicable, - ); - } else if suggest_using_text && code_block.is_ignore { - let sp = sp.from_inner(InnerSpan::new(0, 3)); - diag.span_suggestion( - sp, + if suggest_using_text { + let extended_msg = if is_ignore { "`ignore` code blocks require valid Rust code for syntax highlighting. \ - Mark blocks that do not contain Rust code as text", - String::from("```text,"), + Mark blocks that do not contain Rust code as text" + } else { + "mark blocks that do not contain Rust code as text" + }; + + diag.span_suggestion( + sp.from_inner(InnerSpan::new(0, 3)), + extended_msg, + String::from("```text"), Applicability::MachineApplicable, ); } diag } else { - // We couldn't calculate the span of the markdown block that had the error, so our - // diagnostics are going to be a bit lacking. - let mut diag = self.cx.sess().struct_span_warn( - item.attr_span(self.cx.tcx), - "doc comment contains an invalid Rust code block", - ); - - if code_block.syntax.is_none() && code_block.is_fenced { + let mut diag = lint.build("doc comment contains an invalid Rust code block"); + if suggest_using_text { diag.help("mark blocks that do not contain Rust code as text: ```text"); } @@ -103,7 +119,17 @@ impl<'a, 'tcx> SyntaxChecker<'a, 'tcx> { } diag.emit(); - } + }; + + // Finally build and emit the completed diagnostic. + // All points of divergence have been handled earlier so this can be + // done the same way whether the span is precise or not. + self.cx.tcx.struct_span_lint_hir( + crate::lint::INVALID_RUST_CODEBLOCK, + hir_id, + sp, + diag_builder, + ); } } diff --git a/src/test/rustdoc-ui/ignore-block-help.stderr b/src/test/rustdoc-ui/ignore-block-help.stderr index d45cd92d2d1..313b22c4c7c 100644 --- a/src/test/rustdoc-ui/ignore-block-help.stderr +++ b/src/test/rustdoc-ui/ignore-block-help.stderr @@ -7,11 +7,8 @@ LL | | /// let heart = '❤️'; LL | | /// ``` | |_______^ | + = note: `#[warn(invalid_rust_codeblock)]` on by default = note: error from rustc: character literal may only contain one codepoint -help: `ignore` code blocks require valid Rust code for syntax highlighting. Mark blocks that do not contain Rust code as text - | -LL | /// ```text,ignore (to-prevent-tidy-error) - | ^^^^^^^^ warning: 1 warning emitted diff --git a/src/test/rustdoc-ui/invalid-syntax.stderr b/src/test/rustdoc-ui/invalid-syntax.stderr index 75acdc5ab5f..67e093f9de2 100644 --- a/src/test/rustdoc-ui/invalid-syntax.stderr +++ b/src/test/rustdoc-ui/invalid-syntax.stderr @@ -7,6 +7,7 @@ LL | | /// \__________pkt->size___________/ \_result->size_/ \__pkt->si LL | | /// ``` | |_______^ | + = note: `#[warn(invalid_rust_codeblock)]` on by default = note: error from rustc: unknown start of token: \ = note: error from rustc: unknown start of token: \ = note: error from rustc: unknown start of token: \