Fix JSX linked editing for incomplete property tags with attributes

[Musa Toktas (musatoktas)]

Fixes #56669.

Deleting B from <A.B foo="bar"></A.B> leaves <A. foo="bar"></A.>. The parser currently consumes foo as part of the opening tag name, losing the matching JSX element and its linked editing ranges.

When whitespace after a JSX tag's dot is followed by an attribute assignment, recover with a missing property identifier and leave the attribute for the JSX attribute parser. Valid property names separated by whitespace continue to parse normally. This also handles hyphenated and namespaced attribute names.

Adds linked-editing regression coverage for TSX and JSX, string and expression attributes, keyword/hyphenated/namespaced attributes, nested property names, multiline and spread attributes, valid spaced property names, and mismatched tags. The original reproduction fails on the unmodified main commit.

Validation on Linux with Go 1.27.0, Node 24.21.0, and npm 11.19.1:

• The original regression test fails before the fix at main commit 50d70a3.
• All tsc Go packages passed, including all fourslash and compiler tests. The initial go -C tsc test -p=4 -parallel=4 -count=1 ./... run reached the test host's five-minute limit; the remaining packages passed in a second batch, and the combined results cover every package.
• npx hereby generate, build, lint, and check:format passed.
• The extension, tools, and API tests, Go benchmarks and API benchmarks passed via their individual Hereby tasks.
• The @typescript/typescript and native-preview package builds, both Go modules' mod tidy -diff checks, and go work sync passed. Generation and these checks produced no additional tracked changes.

AI assistance: Codex was used to investigate this issue, implement the parser change, and prepare and run the tests.

[typescript-automation]

This PR doesn't have any linked issues. Please open an issue that references this PR. From there we can discuss and prioritise.

[Copilot]

Copilot review overview

🟢 Approval recommended

The focused parser recovery is well-scoped and covered by comprehensive regression cases.

Review effort: Balanced
Findings: None

What changed in this PR

Recovers incomplete JSX property tags so linked editing remains available when followed by assigned attributes.

Changes:

• Preserves attribute tokens after incomplete dotted tag names.
• Adds TSX/JSX linked-editing regression coverage across attribute forms and edge cases.

File	Description
tsc/​internal/​parser/​parser.go	Adds JSX parser recovery for incomplete property tags.
tsc/​internal/​fourslash/​tests/​linkedEditingJsxTagIncompleteProperty_test.go	Tests linked editing and parser recovery scenarios.

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[Musa Toktas (musatoktas)]

@microsoft-github-policy-service agree