This is because of the combination of two things:

• tsconfig not having any files section. From http://www.typescriptlang.org/docs/handbook/tsconfig-json.html

  If no “files” property is present in a tsconfig.json, the compiler defaults to including all files in the containing directory and subdirectories. When a “files” property is specified, only those files are included.

• Including typescript as an npm dependency : node_modules/typescript/ This means that all of typescript gets included …. there is an implicitly included lib.d.ts in your project anyways (http://basarat.gitbook.io/typescript/content/docs/types/lib.d.ts.html) and its conflicting with the one that ships with the NPM version of typescript.

Fix

Either list files or include explicitly https://basarat.gitbook.io/typescript/project/compilation-context/files 🌹