message: fix(compiler): return `undefined` for `getScriptVersion` when a file doesn't exist in memory cache
diff: @@ -82,7 +82,7 @@ export const initializeLanguageServiceInstance = (
  getScriptFileNames: () => [...memoryCache.files.keys()],
  getScriptVersion: (fileName: string) => {
  const normalizedFileName = normalize(fileName)
  - const version = memoryCache.files.get(normalizedFileName)!.version
  + const version = memoryCache.files.get(normalizedFileName)?.version
  // We need to return `undefined` and not a string here because TypeScript will use
  // `getScriptVersion` and compare against their own version - which can be `undefined`.
  