usage.ts(2,8): error TS2304: Cannot find name 'decorate'.
usage.ts(2,31): error TS2694: Namespace 'A.B.C.D' has no exported member 'E'.


==== types.d.ts (0 errors) ====
    declare namespace A {
        export namespace B {
            export namespace C {
                export namespace D {
                }
            }
        }
    }
==== usage.ts (2 errors) ====
    class Foo {
        f(@decorate user: A.B.C.D.E): void {}
           ~~~~~~~~
!!! error TS2304: Cannot find name 'decorate'.
                                  ~
!!! error TS2694: Namespace 'A.B.C.D' has no exported member 'E'.
    }
    