checker/tests/signature/CanonicalNameNonEmptyTest.java

import org.checkerframework.checker.signature.qual.*;

public class CanonicalNameNonEmptyTest {

  @CanonicalName String nonEmpty1(@CanonicalNameOrEmpty String s) {
    if (s.isEmpty()) {
      return null;
    } else {
      return s;
    }
  }

  @CanonicalName String nonEmpty2(@CanonicalNameOrEmpty String s) {
    if (!s.isEmpty()) {
      return s;
    } else {
      return null;
    }
  }

  @CanonicalName String nonEmpty3(@FullyQualifiedName String s) {
    if (s.isEmpty()) {
      return null;
    } else {
      // :: error: (return)
      return s;
    }
  }
}