framework/tests/all-systems/java8/memberref/Purity.java

import org.checkerframework.dataflow.qual.*;

interface PureFunc {
  @Pure
  String doNothing();
}

class TestPure {

  static String myMethod() {
    return "";
  }

  @Pure
  static String myPureMethod() {
    return "";
  }

  void context() {
    PureFunc f1 = TestPure::myPureMethod;
    // :: error: (purity.methodref)
    PureFunc f2 = TestPure::myMethod;
  }
}