==== tests/cases/compiler/contextualTypingOfObjectLiterals.ts (2 errors) ====
    var obj1: { [x: string]: string; };
    var obj2 = {x: ""};
    obj1 = {}; // Ok
    obj1 = obj2; // Error - indexer doesn't match
    ~~~~
!!! Type '{ x: string; }' is not assignable to type '{ [x: string]: string; }':
!!!   Index signature is missing in type '{ x: string; }'.
    
    function f(x: { [s: string]: string }) { }
    
    f({}); // Ok
    f(obj1); // Ok
    f(obj2); // Error - indexer doesn't match
      ~~~~
!!! Argument of type '{ x: string; }' is not assignable to parameter of type '{ [x: string]: string; }'.