[MelbourneDeveloper]

TLDR

Razor keeps working when a project's SDK is newer than the server's Roslyn (#399). Completion, signature help and rename now handle unfinished and escaped Razor C# (#400, #401, #402, #404), HTML completion and hover are forwarded only in markup (#405), and the HTML projection blanks every directive attribute and the C# in attribute values (#407). C# and F# semantic highlighting use the standard theme scopes and categories (#403). Blazor gets its docs page, a narrated walkthrough film and an announcement post in English, Japanese and Chinese.

Details

C# sidecar

• Newer SDKs: Razor/RazorGenerator.cs (new) is wired into RoslynProjectLoading.WithNew.
  • At project load, it swaps out an SDK Razor compiler that references a newer Microsoft.CodeAnalysis than the sidecar runs. The bundled copy and its two companion files take its place, and a warning names both Roslyn versions.
  • SDK 10.0.401's compiler references Roslyn 5.9; the sidecar runs 5.6. Before this fix, Razor C# features went dark for the whole session.
  • Builds still use the SDK's own generator ([RAZOR-ARCHITECTURE-GENERATOR]).
• Unfinished expressions: Razor/RazorCompletionRecovery.cs (new) handles completion inside an expression the Razor compiler cannot finish: @scores., an @( missing its ), and calls or lambdas inside it.
  • It asks a copy of the file whose expression is finished at the caret. Roslyn's parser supplies the closers, innermost first.
  • RazorSpanMap.Without and RazorProjection.ReadIn read the copy's projection back in the original file ([RAZOR-FEATURES-COMPLETION]).
• Signature help: SignatureHelpResolver offers no signatures for a call whose opening parenthesis has no Razor mapping, such as the generated AddContent and AddAttribute (Razor signature help exposes generated RenderTreeBuilder calls #400).
• Rename: RazorRenameEdits compares a mapped span as a parsed identifier's ValueText, so @class gets its edits (Razor rename drops escaped identifiers such as @class #402).
• HTML forwarding (Razor C# completion in VS Code appends word suggestions from the HTML projection #405): the HTML projection request now carries the caret. The sidecar answers it only where the compiler owns markup, so VS Code (razor-html.ts) forwards completion and hover to its HTML service in markup alone. C# completion lists no longer carry word suggestions taken from the projection.
• HTML projection (Razor HTML projection retains directive attributes and C# attribute values #407): RazorHtmlProjection blanks every directive attribute and the C# in HTML attribute values, while HTML names, quotes and literal text stay.
  • This covers @onclick, @bind:event, and a minimized @onclick:stopPropagation.
  • A directive's children are never copied back as HTML.
  • The compiler gives a minimized directive parameter no span, so its name is read where the attribute before it ends, and only when the text there holds it.

F# sidecar and VS Code highlighting

• FSharpFeatures.fs maps values, functions, properties, events and constructors to their standard LSP token categories. Value-type constructors stay struct. Spans cover only the symbol token, found by the real lexer.
• In package.json, plain C# keywords in csharp, razor and aspnetcorerazor map to keyword.other.cs, so public, class and int no longer take the control-flow colour (Use standard theme keyword colors and correct F# semantic categories #403).

Docs, film and post

• src/website/src/docs/blazor.md (en, ja, zh) covers:
  • what works in a Razor file;
  • HTML in the markup, per editor;
  • how the projection works;
  • supported projects;
  • SDK versions;
  • what is not yet supported (Razor support: Blazor components, Razor Pages and MVC views #397);
  • failure behaviour;
  • Microsoft documentation links.
• src/website/src/blog/blazor-razor-vs-code.md (en, ja, zh) is the announcement post. Its new text-free illustrated cover shows a polished metal @ sculpture with amber fire and cyan-edged glass; all three languages share the artwork with translated alt text. The superseded infographic generator is removed.
• The narrated blazor film ships as MP4 and WebM (Git LFS), with a poster, a social card and en/ja/zh captions. films/blazor.mjs shoots it against demos/blazor-storefront. typeThroughCompletion is now shared from kit/acts/language.mjs.
• The docs sidebar lists Blazor & Razor after F#. A watch page now ignores a non-finite ?t= instead of throwing.

Specs, plans and gates

• RAZOR-SPEC, SHARPLSP-SPEC and DESIGN-SYSTEM describe the new behaviour.
• RAZOR-PLAN records each item, and RAZOR-REVIEW is the regression review with its red/green evidence.
• The C# coverage threshold ratchets up to 95.54%, and the Deslop duplication threshold down to 6.48% (main measures 6.478%, this branch 6.458%).

How Do The Automated Tests Prove It Works?

• RazorNewerSdkTests gives the fixture a newer SDK's Razor compiler. In a fresh sidecar process:

  • hover answers int at @currentCount;
  • Program.cs has no CS0246, and App resolves to App.razor;
  • every Razor project loads the bundled compiler, while a matched SDK keeps its own;
  • an unreadable compiler leaves the project as loaded.

  Both behaviour tests failed before the fix.

• test_latest_sdk_razor_generator_remains_usable (Rust e2e) uses an unpinned fixture copy, which runners with SDK 10.0.401 load with that SDK. It answers hover and resolves App.

• RazorCompletionRecoveryTests: @scores., @(scores., @(basket.MinBy(product => product., …product.Pr and …product.)</p> all failed red. They now return Count or Price, with edits at the Razor caret. Closed @( ) and @{ } controls, an unclosed @code block and a brace closer pass too.

• Razor C# completion in VS Code appends word suggestions from the HTML projection #405: RazorSidecarTests.Positioned_projection_forwards_markup_but_not_csharp_or_its_whitespace and Incomplete_csharp_keeps_html_forwarding_off. The Rust e2e check assert_html_projection_only_in_markup runs over the real Board.razor, and razor-lsp.test.ts asserts that C# completion lists hold no projection words.

• Razor HTML projection retains directive attributes and C# attribute values #407: RazorHtmlProjectionTests.Projection_query_preserves_html_and_utf16_offsets gains six rows: <button @onclick=… disabled="@(scores.Count > 9)">, a plain disabled="@(…)", minimized @onclick:stopPropagation after a directive, after an HTML attribute and after a quoted attribute, and @bind:event="oninput". The failing rows were red before the fix. The fixture test also asserts that scores.Count, @bind and oninput never reach Board's projection.

• RazorProjectionTests: a copy's map keeps only each fragment's part before its inserted closers, so carets past them never map.

• RazorCSharpFeatureTests: signature help inside @( and disabled="@(…)" lists no scaffolding, while real calls still answer. Renaming @class edits every declaration and use.

• Highlighting: FSharpSemanticHighlightingTests checks real-project F# categories with exact spans. semantic-highlighting.test.ts checks that plain and control C# keywords use separate standard scopes, with no hard-coded colours.

• Website (Playwright, desktop plus two phone projects; 901 tests across the affected specs, all passing):

  • docs-nav: the page sits in "Write code" after F#.
  • site-layout: the ja/zh page and post keep the English structure and links.
  • site-videos: the walkthrough plays in every language.
  • video-watch-pages and video-discovery: watch pages and metadata match the real file.
  • video-playback: the film decodes, seeks and resumes.
  • screenshots and mobile-nav cover the new page.
  • "a watch page ignores a ?t= that is not a finite number of seconds, without an error" failed with the currentTime page error before the guard.

• Local CI legs:

  • Lint passes: Rust, Zed, CSharpier, Prettier, ESLint, tsc, spec citations, and the .NET warnings-as-errors build with 0 warnings.
  • Deslop, audit, Zed, Rider, tooling and the website all pass.
  • .NET passes on the final head: C# 716/716, F# 447/447 and Common 125/125. C# coverage is 96.54%, which ratchets its threshold to 95.54%; every line of the changed projection and IR files is covered.
  • VS Code passes locally on macOS, every chunk instrumented: razor 6, lsp 211, fsharp 122, workspace 446, debug 48, debug-breakpoints 62, debug-inspection 34, debug-tests 80, testexplorer 121, testexplorer-frameworks 51, testexplorer-mtp 19, testexplorer-mtp-runners 13, testexplorer-mtp-parity 16 and profiler 323, with 0 failures. realrepo is left to CI because it clones the corpus. The coverage gate over all 14 chunks reads 96.86% (threshold 96.96%, with its 1-point tolerance).
  • The profiler chunk's first local run failed one test, the FsOrderLedger joint soak's "the burn loop is hot", while the machine's load average was 6. The unchanged rerun passed all 323.
  • The Rust legs are re-checked in this PR's pipeline.

Closes #399, closes #400, closes #401, closes #402, closes #403, closes #404, closes #405, closes #407. Refs #397.

The replacement cover passed 18 desktop/phone layout and localization checks, and its rendered desktop and phone headers were visually verified.

Final validation: CI run 39368330371 passed all 52 jobs on head 925b8962; PR merged as ab8e713d. Both profiler chunks passed unchanged. The pre-existing F# hidden-sequence-point attribution defect found during investigation is tracked with a real-engine reproduction in lspkit#18.