code: func (c *CallCommon) Description() string {
  	switch fn := c.Value.(type) {
  	case *Builtin:
  		return "built-in function call"
  	case *MakeClosure:
  		return "static function closure call"
  	case *Function:
  		if fn.Signature.Recv() != nil {
  			return "static method call"
  		}
  		return "static function call"
  	}
  	if c.IsInvoke() {
  		return "dynamic method call" // ("invoke" mode)
  	}
  	return "dynamic function call"
  }
docs: // Description returns a description of the mode of this call suitable
  // for a user interface, e.g., "static method call".