==== tests/cases/compiler/voidAsNonAmbiguousReturnType_1.ts (0 errors) ====
    ///<reference path='voidAsNonAmbiguousReturnType_0.ts'/>
    import fs = require("voidAsNonAmbiguousReturnType_0");
    
    function main() {
     fs.mkdirSync('test'); // should not error - return types are the same
    }
    
==== tests/cases/compiler/voidAsNonAmbiguousReturnType_0.ts (1 errors) ====
    export function mkdirSync(path: string, mode?: number): void;
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! Overload signature is not compatible with function implementation.
    export function mkdirSync(path: string, mode?: string): void {}