text: t6120.scala:5: warning: postfix operator bippy should be enabled
  by making the implicit value scala.language.postfixOps visible.
  This can be achieved by adding the import clause 'import scala.language.postfixOps'
  or by setting the compiler option -language:postfixOps.
  See the Scala docs for value scala.language.postfixOps for a discussion
  why the feature should be explicitly enabled.
    def f = null == null bippy
                         ^
  t6120.scala:5: warning: method bippy in class BooleanOps is deprecated: bobo
    def f = null == null bippy
                         ^
  t6120.scala:5: warning: comparing values of types Null and Null using `==' will always yield true
    def f = null == null bippy
                 ^
  t6120.scala:6: warning: method bippy in class BooleanOps is deprecated: bobo
    def g = true.bippy
                 ^
  error: No warnings can be incurred under -Xfatal-warnings.
  four warnings found
  one error found
  