rustdoc: warn on improperly interleaved HTML/MD by notriddle · Pull Request #158709 · rust-lang/rust

notriddle · 2026-07-03T00:47:27Z

Enhances the rustdoc::invalid_html_tags lint to warn in cases where pulldown-cmark will produce invalid HTML because the Markdown and HTML are improperly nested.

As an extreme example, this code does not do what it looks like it does, and it doesn't produce a warning under current nightly, either:

Figure 1: an X
<svg viewBox="0 0 10 10">
<path
    d="M0 10L10 0M10 10L0 0"
    stroke="black"
>
</svg>

This pull request makes it warn:

error: unopened HTML tag `svg`
  --> $DIR/invalid-html-tags.rs:285:5
   |
LL | /// <svg viewBox="0 0 10 10">
   |     ---- does not match this unclosed tag
...
LL | /// >
   |     - because the Markdown paragraph is interrupted by this block quote
LL | /// </svg>
   |     ^^^^^^ this unopened tag

See also: https://talk.commonmark.org/t/thoughts-on-changing-supported-html-syntax-to-include-the-dangling-closing-angle-bracket/3827

rustbot · 2026-07-03T00:47:33Z

r? @camelid

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notriddle · 2026-07-09T16:57:08Z

r? lolbinarycat

camelid · 2026-07-09T17:18:47Z

Sorry for the delay, I should still be able to review this within the next couple of days. r? @camelid

Co-authored-by: Noah Lev <[email protected]>

notriddle · 2026-07-16T16:23:47Z

About nesting markdown tags within <script>, do you think we should always warn when you do that, even if it's nested correctly? It seems like the behavior would always be misleading, because people want to write JavaScript in their <script> tags, not Markdown.

camelid · 2026-07-16T16:26:01Z

Yeah, I think warning makes sense since the JS won't work if it's turned into HTML.

This is probably not what the user wants: error: nested Markdown emphasis in HTML `style` tag --> $DIR/invalid-html-tags-correct-script-style.rs:11:16 | LL | /// One <style>*emph*</style> | ^^^^^^ Markdown translates this into HTML, but the browser parses it as CSS | help: to turn off Markdown parsing, put the tag at the start of the line | LL ~ /// One LL ~ /// <style>*emph*</style> |

notriddle · 2026-07-16T20:41:21Z

Okay, it's implemented.

camelid

Very cool, great work! Just a few nits.

View changes since this review

camelid · 2026-07-23T21:51:25Z

cc @rust-lang/rustdoc -- I don't think this needs an FCP since it's just adding new cases that are a natural extension to an existing lint, but pinging for visibility

Manishearth · 2026-07-24T06:08:36Z

This is a great idea!

…r=camelid,GuillaumeGomez rustdoc: warn on improperly interleaved HTML/MD Enhances the `rustdoc::invalid_html_tags` lint to warn in cases where pulldown-cmark will produce invalid HTML because the Markdown and HTML are improperly nested. As an extreme example, this code does not do what it looks like it does, and it doesn't produce a warning under current nightly, either: ```markdown Figure 1: an X <svg viewBox="0 0 10 10"> <path d="M0 10L10 0M10 10L0 0" stroke="black" > </svg> ``` This pull request makes it warn: ```text error: unopened HTML tag `svg` --> $DIR/invalid-html-tags.rs:285:5 | LL | /// <svg viewBox="0 0 10 10"> | ---- does not match this unclosed tag ... LL | /// > | - because the Markdown paragraph is interrupted by this block quote LL | /// </svg> | ^^^^^^ this unopened tag ``` See also: https://talk.commonmark.org/t/thoughts-on-changing-supported-html-syntax-to-include-the-dangling-closing-angle-bracket/3827

Rollup of 17 pull requests Successful merges: - #158168 (Added implementation on `set_permissions_nofollow` for all primary platforms) - #138618 (Support using const pointers in asm `const` operand) - #157962 (Function item should not be used as const arg) - #158404 (trait_solver: normalize next-gen region constraints) - #158709 (rustdoc: warn on improperly interleaved HTML/MD) - #159720 (document #[global_allocator] constraints) - #159732 (optimization: don't look for diagnostic/canonical items without rustc_attrs enabled) - #159740 (reuse regular exported_non_generic_symbols logic in Miri) - #159780 (check `extern "custom"` function pointers) - #159786 (rustdoc-js: ignore editor temp files in test folder discovery) - #159819 (std::sync::poison: disable auto_cfg on PoisonError::new) - #155388 (stepping into where-clauses during normalization may be productive) - #155914 (when bailing on ambiguity, don't force other results to ambig) - #159411 ([rustdoc] Correctly handle output options with --show-coverage) - #159439 (Fix(lib/fs/win): Fall back on Win32 delete for `Dir::remove_file`) - #159809 (Avoid `#[target_features]`) - #159826 (Remove redundant `#[rustc_paren_sugar]` feature gate)

…r=camelid,GuillaumeGomez rustdoc: warn on improperly interleaved HTML/MD Enhances the `rustdoc::invalid_html_tags` lint to warn in cases where pulldown-cmark will produce invalid HTML because the Markdown and HTML are improperly nested. As an extreme example, this code does not do what it looks like it does, and it doesn't produce a warning under current nightly, either: ```markdown Figure 1: an X <svg viewBox="0 0 10 10"> <path d="M0 10L10 0M10 10L0 0" stroke="black" > </svg> ``` This pull request makes it warn: ```text error: unopened HTML tag `svg` --> $DIR/invalid-html-tags.rs:285:5 | LL | /// <svg viewBox="0 0 10 10"> | ---- does not match this unclosed tag ... LL | /// > | - because the Markdown paragraph is interrupted by this block quote LL | /// </svg> | ^^^^^^ this unopened tag ``` See also: https://talk.commonmark.org/t/thoughts-on-changing-supported-html-syntax-to-include-the-dangling-closing-angle-bracket/3827

Rollup of 16 pull requests Successful merges: - #138618 (Support using const pointers in asm `const` operand) - #157962 (Function item should not be used as const arg) - #158404 (trait_solver: normalize next-gen region constraints) - #158709 (rustdoc: warn on improperly interleaved HTML/MD) - #159720 (document #[global_allocator] constraints) - #159732 (optimization: don't look for diagnostic/canonical items without rustc_attrs enabled) - #159740 (reuse regular exported_non_generic_symbols logic in Miri) - #159780 (check `extern "custom"` function pointers) - #159786 (rustdoc-js: ignore editor temp files in test folder discovery) - #159819 (std::sync::poison: disable auto_cfg on PoisonError::new) - #155388 (stepping into where-clauses during normalization may be productive) - #155914 (when bailing on ambiguity, don't force other results to ambig) - #159411 ([rustdoc] Correctly handle output options with --show-coverage) - #159439 (Fix(lib/fs/win): Fall back on Win32 delete for `Dir::remove_file`) - #159809 (Avoid `#[target_features]`) - #159826 (Remove redundant `#[rustc_paren_sugar]` feature gate)

…r=camelid,GuillaumeGomez rustdoc: warn on improperly interleaved HTML/MD Enhances the `rustdoc::invalid_html_tags` lint to warn in cases where pulldown-cmark will produce invalid HTML because the Markdown and HTML are improperly nested. As an extreme example, this code does not do what it looks like it does, and it doesn't produce a warning under current nightly, either: ```markdown Figure 1: an X <svg viewBox="0 0 10 10"> <path d="M0 10L10 0M10 10L0 0" stroke="black" > </svg> ``` This pull request makes it warn: ```text error: unopened HTML tag `svg` --> $DIR/invalid-html-tags.rs:285:5 | LL | /// <svg viewBox="0 0 10 10"> | ---- does not match this unclosed tag ... LL | /// > | - because the Markdown paragraph is interrupted by this block quote LL | /// </svg> | ^^^^^^ this unopened tag ``` See also: https://talk.commonmark.org/t/thoughts-on-changing-supported-html-syntax-to-include-the-dangling-closing-angle-bracket/3827

Rollup of 20 pull requests Successful merges: - #138618 (Support using const pointers in asm `const` operand) - #157962 (Lower paths to functions in const args as ConstKind::Error) - #158404 (trait_solver: normalize next-gen region constraints) - #158709 (rustdoc: warn on improperly interleaved HTML/MD) - #159720 (document #[global_allocator] constraints) - #159732 (optimization: don't look for diagnostic/canonical items without rustc_attrs enabled) - #159738 (implement `CovariantUnsafeCell`) - #159740 (reuse regular exported_non_generic_symbols logic in Miri) - #159780 (check `extern "custom"` function pointers) - #159786 (rustdoc-js: ignore editor temp files in test folder discovery) - #159819 (std::sync::poison: disable auto_cfg on PoisonError::new) - #155388 (stepping into where-clauses during normalization may be productive) - #155914 (when bailing on ambiguity, don't force other results to ambig) - #159439 (Fix(lib/fs/win): Fall back on Win32 delete for `Dir::remove_file`) - #159676 (Update wasm-component-ld to 0.5.27) - #159730 (allow accessing the contents of UnsafeCell without going through get) - #159809 (Avoid `#[target_features]`) - #159826 (Remove redundant `#[rustc_paren_sugar]` feature gate) - #159853 (Updated expect messages for `CString` struct and method documentation) - #159877 (Revert "Export `derive` at `core::derive` and `std::derive`")

…uillaumeGomez rustdoc: warn on improperly interleaved HTML/MD Enhances the `rustdoc::invalid_html_tags` lint to warn in cases where pulldown-cmark will produce invalid HTML because the Markdown and HTML are improperly nested. As an extreme example, this code does not do what it looks like it does, and it doesn't produce a warning under current nightly, either: ```markdown Figure 1: an X <svg viewBox="0 0 10 10"> <path d="M0 10L10 0M10 10L0 0" stroke="black" > </svg> ``` This pull request makes it warn: ```text error: unopened HTML tag `svg` --> $DIR/invalid-html-tags.rs:285:5 | LL | /// <svg viewBox="0 0 10 10"> | ---- does not match this unclosed tag ... LL | /// > | - because the Markdown paragraph is interrupted by this block quote LL | /// </svg> | ^^^^^^ this unopened tag ``` See also: https://talk.commonmark.org/t/thoughts-on-changing-supported-html-syntax-to-include-the-dangling-closing-angle-bracket/3827

rust-bors · 2026-07-25T12:39:49Z

💔 Test for 29a4158 failed: CI

Rollup of 20 pull requests Successful merges: - #138618 (Support using const pointers in asm `const` operand) - #157962 (Lower paths to functions in const args as ConstKind::Error) - #158404 (trait_solver: normalize next-gen region constraints) - #158709 (rustdoc: warn on improperly interleaved HTML/MD) - #159720 (document #[global_allocator] constraints) - #159732 (optimization: don't look for diagnostic/canonical items without rustc_attrs enabled) - #159738 (implement `CovariantUnsafeCell`) - #159740 (reuse regular exported_non_generic_symbols logic in Miri) - #159780 (check `extern "custom"` function pointers) - #159786 (rustdoc-js: ignore editor temp files in test folder discovery) - #159819 (std::sync::poison: disable auto_cfg on PoisonError::new) - #155388 (stepping into where-clauses during normalization may be productive) - #155914 (when bailing on ambiguity, don't force other results to ambig) - #159439 (Fix(lib/fs/win): Fall back on Win32 delete for `Dir::remove_file`) - #159676 (Update wasm-component-ld to 0.5.27) - #159730 (allow accessing the contents of UnsafeCell without going through get) - #159809 (Avoid `#[target_features]`) - #159826 (Remove redundant `#[rustc_paren_sugar]` feature gate) - #159853 (Updated expect messages for `CString` struct and method documentation) - #159877 (Revert "Export `derive` at `core::derive` and `std::derive`")

camelid · 2026-07-25T17:26:31Z

@bors retry internal server error?

…r=camelid,GuillaumeGomez rustdoc: warn on improperly interleaved HTML/MD Enhances the `rustdoc::invalid_html_tags` lint to warn in cases where pulldown-cmark will produce invalid HTML because the Markdown and HTML are improperly nested. As an extreme example, this code does not do what it looks like it does, and it doesn't produce a warning under current nightly, either: ```markdown Figure 1: an X <svg viewBox="0 0 10 10"> <path d="M0 10L10 0M10 10L0 0" stroke="black" > </svg> ``` This pull request makes it warn: ```text error: unopened HTML tag `svg` --> $DIR/invalid-html-tags.rs:285:5 | LL | /// <svg viewBox="0 0 10 10"> | ---- does not match this unclosed tag ... LL | /// > | - because the Markdown paragraph is interrupted by this block quote LL | /// </svg> | ^^^^^^ this unopened tag ``` See also: https://talk.commonmark.org/t/thoughts-on-changing-supported-html-syntax-to-include-the-dangling-closing-angle-bracket/3827

…uwer Rollup of 25 pull requests Successful merges: - #138618 (Support using const pointers in asm `const` operand) - #157962 (Lower paths to functions in const args as ConstKind::Error) - #158404 (trait_solver: normalize next-gen region constraints) - #158709 (rustdoc: warn on improperly interleaved HTML/MD) - #159174 (Fix implicit_provenance_casts warnings on Xous) - #159179 (enable `unreachable_cfg_select_predicates` lint as part of `unused` lint group) - #159518 (iter: extend step_by specialization to cover StepBy<RangeIter<{integer}>>) - #159673 (bootstrap: forward -fdebug-prefix-map when using cc) - #159700 (Split non-local `semicolon_in_expressions_from_macros` into a separate lint) - #159720 (document #[global_allocator] constraints) - #159732 (optimization: don't look for diagnostic/canonical items without rustc_attrs enabled) - #159738 (implement `CovariantUnsafeCell`) - #159740 (reuse regular exported_non_generic_symbols logic in Miri) - #159780 (check `extern "custom"` function pointers) - #159785 (Share _Unwind_Exception definition between native and wasm) - #159786 (rustdoc-js: ignore editor temp files in test folder discovery) - #159819 (std::sync::poison: disable auto_cfg on PoisonError::new) - #155388 (stepping into where-clauses during normalization may be productive) - #155914 (when bailing on ambiguity, don't force other results to ambig) - #159204 (Add support to caller_location to rustc_public) - #159439 (Fix(lib/fs/win): Fall back on Win32 delete for `Dir::remove_file`) - #159676 (Update wasm-component-ld to 0.5.27) - #159695 (proc_macro: Fix cfg_attr inner attrs in file modules) - #159730 (allow accessing the contents of UnsafeCell without going through get) - #159809 (Avoid `#[target_features]`)

…r=camelid,GuillaumeGomez rustdoc: warn on improperly interleaved HTML/MD Enhances the `rustdoc::invalid_html_tags` lint to warn in cases where pulldown-cmark will produce invalid HTML because the Markdown and HTML are improperly nested. As an extreme example, this code does not do what it looks like it does, and it doesn't produce a warning under current nightly, either: ```markdown Figure 1: an X <svg viewBox="0 0 10 10"> <path d="M0 10L10 0M10 10L0 0" stroke="black" > </svg> ``` This pull request makes it warn: ```text error: unopened HTML tag `svg` --> $DIR/invalid-html-tags.rs:285:5 | LL | /// <svg viewBox="0 0 10 10"> | ---- does not match this unclosed tag ... LL | /// > | - because the Markdown paragraph is interrupted by this block quote LL | /// </svg> | ^^^^^^ this unopened tag ``` See also: https://talk.commonmark.org/t/thoughts-on-changing-supported-html-syntax-to-include-the-dangling-closing-angle-bracket/3827

…uwer Rollup of 25 pull requests Successful merges: - #159825 (codegen: handle OperandValue::Uninit in codegen_return_terminator) - #138618 (Support using const pointers in asm `const` operand) - #157962 (Lower paths to functions in const args as ConstKind::Error) - #158404 (trait_solver: normalize next-gen region constraints) - #158709 (rustdoc: warn on improperly interleaved HTML/MD) - #159174 (Fix implicit_provenance_casts warnings on Xous) - #159179 (enable `unreachable_cfg_select_predicates` lint as part of `unused` lint group) - #159518 (iter: extend step_by specialization to cover StepBy<RangeIter<{integer}>>) - #159673 (bootstrap: forward -fdebug-prefix-map when using cc) - #159700 (Split non-local `semicolon_in_expressions_from_macros` into a separate lint) - #159720 (document #[global_allocator] constraints) - #159732 (optimization: don't look for diagnostic/canonical items without rustc_attrs enabled) - #159738 (implement `CovariantUnsafeCell`) - #159740 (reuse regular exported_non_generic_symbols logic in Miri) - #159780 (check `extern "custom"` function pointers) - #159786 (rustdoc-js: ignore editor temp files in test folder discovery) - #159819 (std::sync::poison: disable auto_cfg on PoisonError::new) - #155388 (stepping into where-clauses during normalization may be productive) - #155914 (when bailing on ambiguity, don't force other results to ambig) - #159204 (Add support to caller_location to rustc_public) - #159439 (Fix(lib/fs/win): Fall back on Win32 delete for `Dir::remove_file`) - #159676 (Update wasm-component-ld to 0.5.27) - #159695 (proc_macro: Fix cfg_attr inner attrs in file modules) - #159730 (allow accessing the contents of UnsafeCell without going through get) - #159809 (Avoid `#[target_features]`)

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notriddle added 2 commits July 3, 2026 00:08

rustdoc: warn on improperly interleaved HTML/MD

3ffc0fb

rustdoc: add tests for MD/HTML interleaving

cb61eb4

notriddle force-pushed the html-lint-interleaving branch from f995cee to cb61eb4 Compare July 3, 2026 07:09

Clean up and test paragraph and table warn

c9be91c

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camelid reviewed Jul 15, 2026

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Comment thread src/librustdoc/passes/lint/html_tags.rs Outdated

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notriddle and others added 2 commits July 15, 2026 22:14

html_tags: remove in_code_block no-op branch

9bc15a8

html_tags: rename tags based on camelid's nit

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Co-authored-by: Noah Lev <[email protected]>

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Add new invalid_markdown_table rustdoc lint #159583

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rustdoc: use to_ascii_lowercase for HTML tags

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