==== tests/cases/compiler/i3.ts (1 errors) ====
    interface I3 { one?: number; }; 
    var x: {one: number};
    var i: I3;
    
    i = x;
    x = i;
    ~
!!! i3.ts(6,1): error TS2012: Cannot convert 'I3' to '{ one: number; }':
!!! 	Property 'one' defined as optional in type 'I3', but is required in type '{ one: number; }'.