checker/tests/i18n/LocalizedMessage.java

import org.checkerframework.checker.i18n.qual.Localized;

public class LocalizedMessage {
  @Localized String localize(String s) {
    throw new RuntimeException();
  }

  void localized(@Localized String s) {}

  void any(String s) {}

  void stringLiteral() {
    // :: error: (argument)
    localized("ldskjfldj"); // error
    any("lksjdflkjdf");
  }

  void stringRef(String ref) {
    // :: error: (argument)
    localized(ref); // error
    any(ref);
  }

  void localizedRef(@Localized String ref) {
    localized(ref);
    any(ref);
  }

  void methodRet(String ref) {
    localized(localize(ref));
    localized(localize(ref));
  }

  void concatenation(@Localized String s1, String s2) {
    // :: error: (argument)
    localized(s1 + s1); // error
    // :: error: (argument) :: error: (compound.assignment)
    localized(s1 += s1); // error
    // :: error: (argument)
    localized(s1 + "m"); // error
    // :: error: (argument)
    localized(s1 + s2); // error

    // :: error: (argument)
    localized(s2 + s1); // error
    // :: error: (argument)
    localized(s2 + "m"); // error
    // :: error: (argument)
    localized(s2 + s2); // error

    any(s1 + s1);
    any(s1 + "m");
    any(s1 + s2);

    any(s2 + s1);
    any(s2 + "m");
    any(s2 + s2);
  }
}