Daniel Rosenwasser

This commit performs significant **maintenance** and **refactoring** to enhance **TypeScript 6/7 compatibility** for the Copilot extension. It updates the **TypeScript compiler options** in `tsconfig.base.json` by switching module settings, enabling `noEmit`, and dropping explicit `lib` declarations. Code-level adjustments include refactoring module import syntax to `import = require()` for specific packages, changing `module` to `namespace` where appropriate, and fixing type errors related to the stricter signature of `vscode.l10n.t`. Additionally, the **devcontainer setup** and dependencies are updated to provide a more friendly development environment and ensure the codebase remains compatible with modern TypeScript versions.

Merge pull request #298138 from microsoft/updateJsWorkspaceTags

This commit **fixes a typographical error** within the **`workspaceTagsService`** by correcting the package name from `@types/dom` to `@types/web`. This **maintenance change** ensures the service accurately identifies and processes web-related type definitions. The correction was applied to both the internal list of modules being looked for and the associated **telemetry definitions** in `src/vs/workbench/contrib/tags/electron-browser/workspaceTagsService.ts`. This **minor correction** prevents potential misidentification of web types and ensures accurate telemetry data collection for the **`tags` workbench contribution**.

This commit performs **maintenance** on the **workspace tagging service** by updating the internal definitions for **JavaScript-related modules**. Specifically, it modifies `src/vs/workbench/contrib/tags/electron-browser/workspaceTagsService.ts` to refine the lists of JavaScript modules that the system identifies and their corresponding telemetry properties. This ensures more accurate classification and data collection for workspaces containing JavaScript projects, improving the system's understanding of project types without directly altering user-facing functionality.

This commit provides a **documentation update** for **strict-related compiler flags**, clarifying their default behavior. It updates the `defaultValueDescription` in `src/compiler/commandLineParser.ts` and `src/compiler/diagnosticMessages.json` to accurately state that these flags are `true` by default unless the overarching `strict` option is `false`. This **maintenance** task ensures that the **TypeScript compiler's command-line help output** (`tsc --help --all`) provides precise information to users regarding these important configuration options. The change improves the clarity and accuracy of the user experience when configuring strict mode.

This commit performs **maintenance** on the **Fourslash test suite** by explicitly disabling the `strict` compiler option (`// @strict: false`) in a large number of failing test files. This adjustment targets tests that were not designed to specifically validate strict mode behavior and do not contain baseline calls, preventing them from failing due to strictness-related diagnostics. The change improves the **stability and reliability of the test suite**, allowing these tests to continue validating their intended features without being blocked by unintended strict mode issues. This is a **test suite configuration update** and does not alter the compiler's behavior for end-users.

This commit **configures the TypeScript test harness** to explicitly set `strict: false` for various test categories. Specifically, it applies this compiler option to **project tests**, **eval tests** (via `evaluateTypeScript` in `src/harness/evaluatorImpl.ts`), and several **fourslash tests**. This **maintenance change** ensures that these tests run under non-strict type-checking rules, preventing unexpected failures or baseline changes that would arise from stricter compilation. The numerous baseline updates across project and fourslash tests reflect the impact of this configuration change on existing test outputs, aligning them with the intended non-strict behavior.

This commit performs **maintenance** on the **compiler test suite** by adjusting strictness settings for several test cases. It primarily involves adding `@strict: false`, `@noImplicitThis: false`, or `@strictPropertyInitialization: false` compiler options to numerous `tests/cases/compiler` files. These adjustments ensure that specific **language features** and **collision scenarios** are tested correctly, preventing unintended failures due to strict mode checks. Additionally, two `tests/cases/fourslash` files were **refactored** to improve their test logic, such as changing a method to a constructor or a class to an interface, to better validate exact optional property assignments. The overall goal is to enhance the **accuracy and robustness of the test suite** under varying strictness configurations.

This commit **fixes an issue with newline parsing** within the **test harness utilities**, specifically for `// @testOption: value` directives. It **refactors** the `splitContentByNewlines` function in `src/harness/harnessUtils.ts` to use a more robust regular expression, ensuring correct splitting for both `\r\n` and `\n` line endings. This **bug fix** guarantees that test options are consistently interpreted, preventing parsing errors and leading to necessary **baseline updates** for several test cases.

This commit performs significant **refactoring and test updates** to prepare the TypeScript compiler for increased strictness. It primarily involves adding **default initializers to class properties** across numerous test cases (e.g., `Ship`, `Board`, `Foo`, `C`) to align with stricter definite assignment checks. Additionally, it refines **catch clause variable typing** by adding `any` annotations or disabling `useUnknownInCatchVariables` in relevant tests, and updates **metadata emission** for classes and union types under strict compiler flags. These changes ensure the compiler's internal consistency and readiness for future strictness enhancements, impacting type checking and code generation.

This commit **simplifies** the **devcontainer configuration** by **removing** the `sudo corepack enable npm` command from the `postCreateCommand` within `.devcontainer/devcontainer.json`. This **maintenance** change streamlines the **build tools setup** process, eliminating an unnecessary step during the development environment's initialization. Developers will benefit from a slightly faster and cleaner devcontainer creation, as the system no longer explicitly enables `npm` via `corepack` in this stage.

This commit performs a **version bump** for the project, updating the internal `versionMajorMinor` constant within the **compiler core** from '5.9' to '6.0'. This `chore` signifies the preparation for a **new major release**, indicating potential breaking changes or significant new features. The change in `src/compiler/corePublic.ts` ensures that the public-facing version information accurately reflects the upcoming `6.0` release.

This commit **enhances the TypeScript compiler's diagnostic system** by providing more specific error messages for issues related to **`verbatimModuleSyntax`**. It introduces a new helper function, `getVerbatimModuleSyntaxErrorMessage`, in `src/compiler/checker.ts` to generate these improved diagnostics. Existing error messages in `src/compiler/diagnosticMessages.json` are renamed, and a new, more precise message is added. This **feature improvement** ensures that developers receive clearer and more actionable feedback when encountering `verbatimModuleSyntax` errors, with updated test baselines reflecting these changes.

This commit **refactors** the **outlining elements collection service** within `src/services/outliningElementsCollector.ts`. Specifically, it modifies the `addNodeOutliningSpans` function to explicitly visit the end-of-file token using a trailing `visitNode` call. This change streamlines the collection of **outlining spans** by removing the need to create a new array to include this token. The **refactoring** simplifies the internal logic for **code folding** functionality, making the process more direct and efficient.

This commit **fixes** an issue in the **TypeScript compiler's checker** where diagnostics for **type assertions** were incorrectly positioned when the `erasableSyntaxOnly` compiler option was active. It adjusts the start and end positions for these diagnostics within `src/compiler/checker.ts`, ensuring accurate error reporting. This **bug fix** improves the reliability of compiler feedback for users leveraging `erasableSyntaxOnly`, providing more precise error locations. A new test case, `erasableSyntaxOnly2.ts`, has been added to validate the fix and prevent future regressions.

This commit performs a **version bump** for the project, updating the internal `versionMajorMinor` constant from `5.8` to `5.9`. This **maintenance** change is located in `src/compiler/corePublic.ts`, which defines core public constants for the system. The update directly impacts the **TypeScript compiler's reported version**, signaling the transition to the **5.9 release cycle**. This is crucial for tools and users relying on the compiler's self-reported version to determine compatibility and available features.

This commit provides a **bug fix** to improve the accuracy of **compiler diagnostic messages**. It **corrects an error message** related to **import assertions** within the **TypeScript compiler**, specifically changing the incorrect reference from 'asserts' to 'assert' in `src/compiler/checker.ts` and `src/compiler/diagnosticMessages.json`. This ensures that developers receive the correct terminology when encountering issues with import assertions, enhancing the clarity of error reporting. The change also updates several test baselines to reflect the corrected diagnostic output.