func (c *CallCommon) Signature() *types.Signature {
	if c.Method != nil {
		return c.Method.Type().(*types.Signature)
	}
	return c.Value.Type().Underlying().(*types.Signature)
}
func (c *CallCommon) Signature() *types.Signature {
	if c.Method != nil {
		return c.Method.Type().(*types.Signature)
	}
	return c.Value.Type().Underlying().(*types.Signature)
}
// Signature returns the signature of the called function.
//
// For an "invoke"-mode call, the signature of the interface method is
// returned.
//
// In either "call" or "invoke" mode, if the callee is a method, its
// receiver is represented by sig.Recv, not sig.Params().At(0).
//