typescript - Cannot reference declared file in module when class is inside the same module -

i have declaration file: decl.d.ts.

declare module mymodule {   export class myclass {} } 

and source file: file.ts.

/// <reference path="./decl.d.ts"/>  export module mymodule {   export class myotherclass {     myfunction(): void {       var myvar: mymodule.myclass;     }   } } 

problem mymodule.myclass not recognized. if remove module in file.ts, can reference class.

what going wrong?