==== tests/cases/compiler/parameterPropertyInConstructor2.ts (3 errors) ====
    module mod {
      class Customers {
        constructor(public names: string);
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! Overload signature is not compatible with function implementation.
                    ~~~~~~~~~~~~~~~~~~~~
!!! A parameter property is only allowed in a constructor implementation.
        constructor(public names: string, public ages: number) {
                           ~~~~~
!!! Duplicate identifier 'names'.
        }
      }
    }