code: @Nonnull
      public BugInstance addSourceLine(BytecodeScanningDetector visitor, int pc) {
          SourceLineAnnotation sourceLineAnnotation = SourceLineAnnotation.fromVisitedInstruction(visitor.getClassContext(),
                  visitor, pc);
          if (sourceLineAnnotation != null) {
              add(sourceLineAnnotation);
          }
          return this;
      }
docs: Add a source line annotation for instruction whose PC is given in the
  method that the given visitor is currently visiting. Note that if the
  method does not have line number information, then no source line
  annotation will be added.
  
  @param visitor
  a BytecodeScanningDetector that is currently visiting the
  method
  @param pc
  bytecode offset of the instruction
  @return this object