tests/cases/conformance/ambient/ambientExternalModuleInsideNonAmbient.ts(2,5): error TS2668: 'export' modifier cannot be applied to ambient modules and module augmentations since they are always visible.
tests/cases/conformance/ambient/ambientExternalModuleInsideNonAmbient.ts(2,27): error TS2435: Ambient modules cannot be nested in other modules or namespaces.


==== tests/cases/conformance/ambient/ambientExternalModuleInsideNonAmbient.ts (2 errors) ====
    module M {
        export declare module "M" { }
        ~~~~~~
!!! error TS2668: 'export' modifier cannot be applied to ambient modules and module augmentations since they are always visible.
                              ~~~
!!! error TS2435: Ambient modules cannot be nested in other modules or namespaces.
    }