code: func (c *CallCommon) StaticCallee() *Function {
  	switch fn := c.Value.(type) {
  	case *Function:
  		return fn
  	case *MakeClosure:
  		return fn.Fn.(*Function)
  	}
  	return nil
  }
docs: // StaticCallee returns the callee if this is a trivially static
  // "call"-mode call to a function.