TypeScript

This is a regression in TypeScript 7.0.2 (worked in 6.0.3): incremental builds keep stale diagnostics when a declare global block inside a package's module declaration file changes, because the .tsbuildinfo cache is not invalidated. The incremental run reports no errors while a clean build reports them (e.g., TS2345).

Fixes and workarounds:
1. Upgrade to TypeScript 7.1+ — the bug is confirmed fixed in 7.1 nightly (npm i typescript@next).
2. If stuck on 7.0.x, delete the build info file before each run to force a full re-check: rm -f <path>.tsbuildinfo && tsc --noEmit --incremental --tsBuildInfoFile <path>.tsbuildinfo -p tsconfig.json.
3. Alternatively, verify types with a clean non-incremental run: tsc --noEmit -p tsconfig.json.

Note: this commonly affects type-test setups (e.g., Vitest/expect-webdriverio) that run tsc --noEmit --incremental against global type augmentations from packages in node_modules.

This is a known bug in TypeScript 7.0.2. With isolatedModules + declaration + incremental, when a global-scope file (e.g. declare global or @types/node) changes in the same run as source files, dependent files' .d.ts are not re-emitted, and the .tsbuildinfo incorrectly records them as up-to-date, so the stale output persists across builds.

The fix (microsoft/typescript-go#4665) will NOT be backported to 7.0.x — the team only backports critical security/stability fixes. Solutions:

1. Upgrade to TypeScript 7.1 (or nightly typescript@7.1.0-dev.20261011.1 or later): npm install typescript@next.
2. Workaround on 7.0.2: delete the .tsbuildinfo file (or run a clean build) whenever a dependency bump or edit touches global declarations, forcing a full re-emit of all declaration files.

This is a regression in the native TypeScript 7.0.2 compiler (tsgo); the same code compiles cleanly in TS 5.9.3 and 6.0.3. Workaround: index the mapped type by its own keyof instead of recomputing the remapped key set with Exclude. Extract the mapped type into an alias and use Map<T>[keyof Map<T>]:

type EntryPathMap<T> = {
  [K in keyof T & string as K extends '_key' ? never : K]: [PathTuples<T[K]>] extends [never]
    ? never
    : readonly [K, ...ChildPaths<T[K]>];
};
type PathTuples<T> = T extends object ? EntryPathMap<T>[keyof EntryPathMap<T>] : [];

keyof EntryPathMap<T> resolves to the same key set as Exclude<keyof T & string, '_key'> and is accepted by all compilers. Alternatively, pin TypeScript to 5.9.3 or 6.0.3 (@typescript/typescript6) until the native compiler regression is fixed.

This is a race condition in the typescript-go LSP file watcher (lspwatcher.WatchFiles). The watcher releases its lock while installing a subscription; if Watcher.Close runs in between, it sets w.watches = nil, and the subsequent map assignment panics. It typically triggers when the client closes documents and shuts down while a background project snapshot update re-registers watches — i.e., when the client does NOT advertise dynamic workspace/didChangeWatchedFiles registration and the server uses its internal watcher. tsgo --lsp --stdio exits with status 2.

**Fix:** Update your TypeScript native preview (typescript@7.x / tsgo) to a build that includes the fix from microsoft/typescript-go#4845, which rechecks closed under the lock before publishing the subscription and returns the lspwatcher: closed error instead of panicking.

**Workarounds until you can upgrade:**
1. Have your LSP client advertise dynamic file-watch registration (workspace.didChangeWatchedFiles.dynamicRegistration: true) so the server uses client-managed watchers instead of the internal watcher that contains the race.
2. If building from source, patch internal/lsp/lspwatcher/lspwatcher.go (WatchFiles): after reacquiring w.mu, recheck w.closed; if closed, close the unpublished subscription and return the existing lspwatcher: closed error. Do not suppress the panic or disable the watcher.

This is a documentation bug in TypeScript 5.0.4's lib.decorators.d.ts: the example references ClassMethodDecoratorFunction, but that type was never shipped in the lib files (the example also contains invalid function syntax). Workaround: declare the type yourself in your project:

type ClassMethodDecoratorFunction<
  This = unknown,
  Value extends (this: This, ...args: any[]) => any = (this: This, ...args: any[]) => any
> = (
  value: Value,
  context: ClassMethodDecoratorContext<This, Value>
) => Value | void;

Then the bound-method example works:

const bound: ClassMethodDecoratorFunction = function (value, context) {
  if (context.private) throw new TypeError("Not supported on private methods.");
  context.addInitializer(function (this: any) {
    this[context.name] = this[context.name].bind(this);
  });
};

Notes: use a normal function expression (the shorthand in the official example is invalid syntax), and cast this to any (or use a mapped access) to avoid the implicit-any error on this[context.name]. Upgrading to a newer TypeScript version is also recommended, as the incorrect example in lib.decorators.d.ts was corrected after 5.0.x. A ready-made type is available in the community at ajvincent/es-membrane (ClassMethodDecoratorFunction.d.mts).