bug550.check

来自「JAVA 语言的函数式编程扩展」· CHECK 代码 · 共 8 行

bug550.scala:6: error: class List takes type parameters
  def sum[a](xs: List)(implicit m: Monoid[a]): a =
                 ^
bug550.scala:8: error: no implicit argument matching parameter type Monoid[Nothing] was found.
  sum(List(1,2,3))
  ^
two errors found