The context is an annotation processor in which TypeElement is not imported. I get an initial error, which is good, then a followup error, which would be better if it were not generated.

/w/jjg/work/DiagsExamples/6966604-filer/7/langtools/test/tools/javac/processing/filer/TestLastRound.java:60: cannot find symbol
    public boolean process(Set<? extends TypeElement> annotations,
                                         ^
  symbol: class TypeElement
  location: class TestLastRound
/w/jjg/work/DiagsExamples/6966604-filer/7/langtools/test/tools/javac/processing/filer/TestLastRound.java:60: type parameter ? extends TypeElement is not within its bound
    public boolean process(Set<? extends TypeElement> annotations,
                               ^
2 errors