With the changes described in microsoft/TypeScript#9646 now there are build errors in projects using reflect-metadata.
We are using angular, webpack and awesome-typescript-loader and experiencing now:
"File '.../node_modules/reflect-metadata/Reflect.d.ts' not found" error during the build.
Changing import "./reflect-metadata"; to import "./reflect-metadata.d.ts"; in typings.d.ts fixes the problem.