text: // Generic call with parameter of object type with member of function type of n args passed object whose associated member is call signature with n+1 args
  function foo(arg1) {
      return arg1.cb(null);
  }
  var arg = {
      cb: function(x) {
          return "";
      }
  };
  var r = foo(arg); // {}
  // more args not allowed
  var r2 = foo({
      cb: function(x, y) {
          return "";
      }
  }); // error
  var r3 = foo({
      cb: function(x, y) {
          return "";
      }
  }); // error
  function foo2(arg2) {
      return arg2.cb(null, null);
  }
  // fewer args ok
  var r4 = foo(arg); // {}
  var r5 = foo({
      cb: function(x) {
          return "";
      }
  }); // {}
  var r6 = foo({
      cb: function(x) {
          return "";
      }
  }); // string
  var r7 = foo({
      cb: function() {
          return "";
      }
  }); // string
  