diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs index 2336b52619ab8..449925a9cc715 100644 --- a/compiler/rustc_lint/src/lib.rs +++ b/compiler/rustc_lint/src/lib.rs @@ -70,7 +70,7 @@ use rustc_middle::ty::TyCtxt; use rustc_session::lint::builtin::{ BARE_TRAIT_OBJECTS, BROKEN_INTRA_DOC_LINKS, ELIDED_LIFETIMES_IN_PATHS, EXPLICIT_OUTLIVES_REQUIREMENTS, INVALID_CODEBLOCK_ATTRIBUTES, INVALID_HTML_TAGS, - MISSING_DOC_CODE_EXAMPLES, NON_AUTOLINKS, PRIVATE_DOC_TESTS, + INVALID_RUST_CODEBLOCK, MISSING_DOC_CODE_EXAMPLES, NON_AUTOLINKS, PRIVATE_DOC_TESTS, }; use rustc_span::symbol::{Ident, Symbol}; use rustc_span::Span; @@ -319,6 +319,7 @@ fn register_builtins(store: &mut LintStore, no_interleave_lints: bool) { BROKEN_INTRA_DOC_LINKS, PRIVATE_INTRA_DOC_LINKS, INVALID_CODEBLOCK_ATTRIBUTES, + INVALID_RUST_CODEBLOCK, MISSING_DOC_CODE_EXAMPLES, PRIVATE_DOC_TESTS, INVALID_HTML_TAGS diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs index 1c692d4f20762..875798580d6bf 100644 --- a/compiler/rustc_lint_defs/src/builtin.rs +++ b/compiler/rustc_lint_defs/src/builtin.rs @@ -1890,6 +1890,18 @@ declare_lint! { "codeblock attribute looks a lot like a known one" } +declare_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 + pub INVALID_RUST_CODEBLOCK, + Warn, + "codeblock could not be parsed as valid Rust or is empty" +} + declare_lint! { /// The `missing_crate_level_docs` lint detects if documentation is /// missing at the crate root. This is a `rustdoc` only lint, see the @@ -2891,6 +2903,7 @@ declare_lint_pass! { BROKEN_INTRA_DOC_LINKS, PRIVATE_INTRA_DOC_LINKS, INVALID_CODEBLOCK_ATTRIBUTES, + INVALID_RUST_CODEBLOCK, MISSING_CRATE_LEVEL_DOCS, MISSING_DOC_CODE_EXAMPLES, INVALID_HTML_TAGS, 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 9d45f6fd0d348..7257acaa6590c 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 f5bc90e6f9621..e8c7e380e749f 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 0f084c5c11f39..3e2a84e3d03aa 100644 --- a/compiler/rustc_typeck/src/check/upvar.rs +++ b/compiler/rustc_typeck/src/check/upvar.rs @@ -347,7 +347,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { /// /// InferBorrowKind results in a structure like this: /// - /// ``` + /// ```text /// { /// Place(base: hir_id_s, projections: [], ....) -> (hir_id_L5, ByValue), /// Place(base: hir_id_p, projections: [Field(0, 0)], ...) -> (hir_id_L2, ByRef(MutBorrow)) @@ -356,7 +356,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { /// ``` /// /// After the min capture analysis, we get: - /// ``` + /// ```text /// { /// hir_id_s -> [ /// Place(base: hir_id_s, projections: [], ....) -> (hir_id_L4, ByValue) diff --git a/src/doc/rustdoc/src/lints.md b/src/doc/rustdoc/src/lints.md index 41292b3d83841..33a91a454cf8a 100644 --- a/src/doc/rustdoc/src/lints.md +++ b/src/doc/rustdoc/src/lints.md @@ -286,6 +286,41 @@ 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 | | /// ``` +| |_______^ + +warning: Rust code block is empty +--> src/lib.rs:8:5 +| +8 | /// ```rust +| ^^^^^^^ +``` + ## non_autolinks This lint is **nightly-only** and **warns by default**. It detects links which diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs index 7e85342ac7d5d..dff394f5b7b91 100644 --- a/src/librustdoc/core.rs +++ b/src/librustdoc/core.rs @@ -308,6 +308,7 @@ crate fn create_config( let private_doc_tests = rustc_lint::builtin::PRIVATE_DOC_TESTS.name; let no_crate_level_docs = rustc_lint::builtin::MISSING_CRATE_LEVEL_DOCS.name; let invalid_codeblock_attributes_name = rustc_lint::builtin::INVALID_CODEBLOCK_ATTRIBUTES.name; + let invalid_rust_codeblock = rustc_lint::builtin::INVALID_RUST_CODEBLOCK.name; let invalid_html_tags = rustc_lint::builtin::INVALID_HTML_TAGS.name; let renamed_and_removed_lints = rustc_lint::builtin::RENAMED_AND_REMOVED_LINTS.name; let non_autolinks = rustc_lint::builtin::NON_AUTOLINKS.name; @@ -323,6 +324,7 @@ crate fn create_config( private_doc_tests.to_owned(), no_crate_level_docs.to_owned(), invalid_codeblock_attributes_name.to_owned(), + invalid_rust_codeblock.to_owned(), invalid_html_tags.to_owned(), renamed_and_removed_lints.to_owned(), unknown_lints.to_owned(), diff --git a/src/librustdoc/passes/check_code_block_syntax.rs b/src/librustdoc/passes/check_code_block_syntax.rs index 0c76dc571beee..7a8eeac64d72f 100644 --- a/src/librustdoc/passes/check_code_block_syntax.rs +++ b/src/librustdoc/passes/check_code_block_syntax.rs @@ -1,6 +1,8 @@ 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::lint; use rustc_session::parse::ParseSess; use rustc_span::source_map::{FilePathMapping, SourceMap}; use rustc_span::{FileName, InnerSpan}; @@ -47,22 +49,46 @@ 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, &dox, &code_block.range, &item.attrs) - { - let warning_message = if buffer.has_errors { + 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 mark_with_text = code_block.syntax.is_none() && code_block.is_fenced; + + // The span and whether it is precise or not. + let (sp, precise_span) = match super::source_span_for_markdown_range( + self.cx, + &dox, + &code_block.range, + &item.attrs, + ) { + Some(sp) => (sp, true), + None => (super::span_of_attrs(&item.attrs).unwrap_or(item.source.span()), 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" }; - let mut diag = self.cx.sess().struct_span_warn(sp, warning_message); - - if code_block.syntax.is_none() && code_block.is_fenced { - let sp = sp.from_inner(InnerSpan::new(0, 3)); + let mut diag = lint.build(msg); + if mark_with_text { diag.span_suggestion( - sp, + sp.from_inner(InnerSpan::new(0, 3)), "mark blocks that do not contain Rust code as text", String::from("```text"), Applicability::MachineApplicable, @@ -71,14 +97,8 @@ impl<'a, 'tcx> SyntaxChecker<'a, 'tcx> { 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( - super::span_of_attrs(&item.attrs).unwrap_or(item.source.span()), - "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 mark_with_text { diag.help("mark blocks that do not contain Rust code as text: ```text"); } @@ -91,7 +111,17 @@ 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( + lint::builtin::INVALID_RUST_CODEBLOCK, + hir_id, + sp, + diag_builder, + ); } } diff --git a/src/test/rustdoc-ui/invalid-syntax.stderr b/src/test/rustdoc-ui/invalid-syntax.stderr index 9a7a4d2101362..a55a0b1d90e24 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: \