code: func (c ModuleCallInstance) ModuleInstance(caller ModuleInstance) ModuleInstance {
  	return caller.Child(c.Call.Name, c.Key)
  }
docs: // ModuleInstance returns the address of the module instance that corresponds
  // to the receiving call instance when resolved in the given calling module.
  // In other words, it returns the child module instance that the receving
  // call instance creates.