Support LSP source.fixAll

[jakebailey]

This adds source.fixAll support. For example, running the "Fix All" command in VS Code nets:

2026-04-09 15:10:58.188 [trace] Sending request 'textDocument/codeAction - (11)'.
Params: {
    "textDocument": {
        "uri": "file:///home/jabaile/work/vscode/extensions/typescript-language-features/src/lazyClientHost.ts"
    },
    "range": {
        "start": {
            "line": 33,
            "character": 17
        },
        "end": {
            "line": 33,
            "character": 17
        }
    },
    "context": {
        "diagnostics": [],
        "only": [
            "source.fixAll"
        ],
        "triggerKind": 1
    }
}

2026-04-09 15:10:58.474 [trace] Received response 'textDocument/codeAction - (11)' in 286ms.
Result: [
    {
        "title": "Fix All",
        "kind": "source.fixAll",
        "edit": {
            "changes": {
                "file:///home/jabaile/work/vscode/extensions/typescript-language-features/src/lazyClientHost.ts": [
                    {
                        "range": {
                            "start": {
                                "line": 19,
                                "character": 0
                            },
                            "end": {
                                "line": 19,
                                "character": 0
                            }
                        },
                        "newText": "import { ActiveJsTsEditorTracker } from './ui/activeJsTsEditorTracker';\nimport { Lazy } from './utils/lazy';\n"
                    }
                ]
            }
        }
    }
]

This involved porting more fourslash code; mostly code stolen from #3304. But, it required more to also handle imports as we now have a test which breaks the import elision heuristic in the converter. Yay.

[Copilot]

Pull request overview

Adds source.fixAll support to the Go TypeScript LSP/LS implementation, along with “fix all missing imports” aggregation and new fourslash conversion/test infrastructure to validate code-fix behavior.

Changes:

• Advertise and implement the source.fixAll code action kind in the LSP/LS code action pipeline.
• Add a “get all code actions” path for import fixes, coalescing multiple missing-import diagnostics into consolidated edits via ImportAdder.
• Extend the fourslash converter and add generated tests/helpers for codeFix, codeFixAvailable, and codeFixAll.

Reviewed changes

Copilot reviewed 27 out of 28 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
internal/lsp/server.go	Advertises source.fixAll as a supported code action kind.
internal/ls/codeactions.go	Adds source.fixAll handling and kind hierarchy matching helper.
internal/ls/codeactions_importfixes.go	Implements GetAllCodeActions for import-related “fix all” aggregation.
internal/ls/autoimport/import_adder.go	Extends ImportAdder with AddImportFix to accumulate fixes directly.
internal/fourslash/fourslash.go	Adds fourslash helpers for verifying code fixes and “codeFixAll”.
internal/fourslash/_scripts/failingTests.txt	Marks additional generated fourslash tests as failing/skipped.
internal/fourslash/_scripts/convertFourslash.mts	Ports fourslash parsing/generation for code-fix verification and import handling.
internal/fourslash/tests/gen/importNameCodeFix_types_classic_test.go	New generated code-fix-all test coverage (classic module resolution).
internal/fourslash/tests/gen/importNameCodeFix_typeOnly2_test.go	New generated code-fix-all test coverage (type-only scenarios).
internal/fourslash/tests/gen/importNameCodeFix_require_UMD_test.go	New generated code-fix test coverage for require + UMD.
internal/fourslash/tests/gen/importNameCodeFix_require_test.go	New generated code-fix-all test coverage for require imports.
internal/fourslash/tests/gen/importNameCodeFix_require_namedAndDefault_test.go	New generated code-fix-all test coverage for named+default require shape.
internal/fourslash/tests/gen/importNameCodeFix_require_importVsRequire_moduleTarget_test.go	New generated test coverage for import vs require selection based on module target.
internal/fourslash/tests/gen/importNameCodeFix_require_importVsRequire_importWins_test.go	New generated test coverage for import vs require precedence (import wins).
internal/fourslash/tests/gen/importNameCodeFix_require_importVsRequire_addToExistingWins_test.go	New generated test coverage for “add to existing” precedence.
internal/fourslash/tests/gen/importNameCodeFix_require_addToExisting_test.go	New generated test coverage for updating existing require destructuring.
internal/fourslash/tests/gen/importNameCodeFix_jsExtension_test.go	New generated test coverage for .js/.jsx extension module specifiers.
internal/fourslash/tests/gen/importNameCodeFix_exportEquals_test.go	New generated test coverage for export = import forms.
internal/fourslash/tests/gen/importNameCodeFix_all2_test.go	New generated code-fix-all test coverage (multiple imports).
internal/fourslash/tests/gen/importNameCodeFix_all_test.go	New generated broad code-fix-all coverage across many import shapes.
internal/fourslash/tests/gen/importNameCodeFix_all_promoteType_test.go	New generated code-fix-all coverage for promote-type-only cases.
internal/fourslash/tests/gen/importNameCodeFix_all_js_test.go	New generated code-fix-all coverage in JS + JSDoc import types.
internal/fourslash/tests/gen/importNameCodeFix_add_all_missing_imports_test.go	New generated code-fix-all coverage for multiple missing imports.
internal/fourslash/tests/gen/codeFixAddMissingImportForReactJsx2_test.go	New generated code-fix-all coverage for react-jsxdev missing imports.
internal/fourslash/tests/gen/codeFixAddMissingImportForReactJsx1_test.go	New generated code-fix-all coverage for react-jsx missing imports.
internal/fourslash/tests/gen/autoImportTypeOnlyPreferred3_test.go	New generated tests for type-only auto-import preference interactions.
internal/fourslash/tests/gen/addAllMissingImportsNoCrash_test.go	New generated regression test ensuring “add all missing imports” doesn’t crash.

[gabritto]

Had some questions but this looks good

[Copilot]

Pull request overview

Copilot reviewed 30 out of 31 changed files in this pull request and generated 4 comments.