prog.ts(2,7): error TS2322: Type 'string' is not assignable to type 'boolean'.
prog.ts(3,9): error TS2339: Property 'runANonExistentMethod' does not exist on type 'boolean'.
prog.ts(4,18): error TS2345: Argument of type 'boolean' is not assignable to parameter of type 'number'.