g.js

function def() {
  var myx;
  Object.defineProperty(global, 'x', {
    get: function() {
      return myx;
    },
    set: function(val) {
      console.log('setter!');
      myx = val;
    },
    configurable: true,
    enumerable: true
  });

  // This one is fine.
  this.eval('var x = function y() {}');

  console.log(myx.name, this.x.name);

  // This one throws a redeclaration error if we didn't
  // set configurable:true in the property.  However,
  // wtf?  Doesn't call the setter!?
  this.eval('function x() {}');

  console.log(myx.name, this.x.name);
}

def();