docs: @Nonnull
      public BugInstance addSourceLine(ClassContext classContext, MethodGen methodGen, String sourceFile, InstructionHandle start,
              InstructionHandle end) {
          // Make sure start and end are really in the right order.
          if (start.getPosition() > end.getPosition()) {
              InstructionHandle tmp = start;
              start = end;
              end = tmp;
          }
          SourceLineAnnotation sourceLineAnnotation = SourceLineAnnotation.fromVisitedInstructionRange(classContext, methodGen,
                  sourceFile, start, end);
          if (sourceLineAnnotation != null) {
              add(sourceLineAnnotation);
          }
          return this;
      }