Document highlights

[johnfav03]

Fixes #1500

This PR implements provideDocumentHighlights and the corresponding fourslash tests/functions; the implementation covers syntactic highlights fully, but is missing several cases in semantic highlights due to unimplemented cases in getReferencedSymbolsForNode. Some prevalent examples from the failing test cases include:

• export logic in getReferencedSymbolsForSymbol
  • cases: getDocumentHighlightInExport, getDocumentHighlightInTypeExport`
• getReferencesForStringLiteral in getReferencedSymbolsForNode
  • cases: getDocumentHighlightTemplateStrings, getOccurrencesStringLiterals, getOccurrencesStringLiteralTypes
• constructor logic in getReferencesAtLocation
  • cases: getOccurencesClassExpressionConstructor, getOccurrencesConstructor, getOccurrencesConstructor2

[johnfav03]

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[Copilot]

Pull Request Overview

This PR adds support for "Document highlights" functionality in the testing framework. Document highlights show related occurrences of symbols in a document when the user hovers or selects a symbol.

• Adds a new baseline test type for documentHighlights test cases
• Creates extensive test coverage for various TypeScript language constructs including classes, interfaces, keywords, modifiers, and control flow statements
• Includes test cases for edge cases like inherited properties, parameter properties, and JSX elements

Reviewed Changes

Copilot reviewed 224 out of 224 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
testdata/baselines/reference/submodule/fourslash/findRenameLocations/renameDefaultImportDifferentName.baseline.jsonc.diff	Diff file showing baseline changes for rename functionality
testdata/baselines/reference/submodule/fourslash/findRenameLocations/renameDefaultImportDifferentName.baseline.jsonc	Baseline for testing rename operations on default imports with different names
testdata/baselines/reference/fourslash/findAllReferences/renameDefaultImportDifferentName.baseline.jsonc	Baseline for find all references functionality on default imports
testdata/baselines/reference/fourslash/findAllReferences/findReferencesJSXTagName3.baseline.jsonc	Baseline for finding references in JSX tag names
testdata/baselines/reference/fourslash/documentHighlights/*.baseline.jsonc	100+ baseline files covering document highlights for various TypeScript constructs including keywords, modifiers, classes, interfaces, control flow, and edge cases

[andrewbranch]

Is there a pattern among the failing tests, i.e. something they’re blocked on or a specific follow-up task?

[johnfav03]

These tests are giving an incorrect output due to a missing case in getReferencedSymbolsForNode() in findAllReferences - I'll update the PR description with cases that could be updated as a follow-up task

[andrewbranch]

This is a great first PR 👏

[iisaduan]

Great work! Seems like you've quickly gotten a good hang of the codebase :D

Requesting changes because I noticed an incorrect port of some logic, and I also left comments on some refactors and code/comment clean up

[iisaduan]

Looks good! Great work!

[jakebailey]

Curious, what kinds of failures are these? Crashes? If they're crashes, I would definitely want to double check these because document highlight is something that happens automatically on cursor move, which means we could be spamming panics.

[jakebailey]

Ah, these must be https://github.com/microsoft/typescript-go/pull/1699/files#r2360590494, which I didn't notice since it was attached to an old rev.

[iisaduan]

They are because of unimplemented cases in FAR, so the test fails when no highlights are returned (which is fine in editor)

[iisaduan]

String references and a lot of the keyword references aren't implemented

[johnfav03]

Only two tests fail, and it's due to unexpected responses in fourslash.go from modules that arent documentHighlights. The tests are FindAllRefsForModule and TestJsdocTypedefTagServices, which return an unexpected response from FindAllReferences and QuickInfo respectively.

[jakebailey]

I think this looks good, but in checker.ts it does look like sometimes things take more time than expected, though it's not clear if that's inherent or just because it was doing a hover or something at the same time:

I filtered the LSP output to Received response 'textDocument/documentHighlight and then moved my cursor / mouse around.

To be clear, it usually isn't this way, it's just sometimes randomly it takes 100ms, or is cancelled, which is also fine too.

It does make me wonder if there's an implementation of this that could avoid FAR and the checker entirely. Or a FAR modification to say "no checker use" that is mostly accurate. Especially because we are scoping to one file.