code: @Nonnull
      public BugInstance addSourceLine(ClassContext classContext, MethodGen methodGen, String sourceFile,
              @Nonnull InstructionHandle handle) {
          SourceLineAnnotation sourceLineAnnotation = SourceLineAnnotation.fromVisitedInstruction(classContext, methodGen,
                  sourceFile, handle);
          if (sourceLineAnnotation != null) {
              add(sourceLineAnnotation);
          }
          return this;
      }
docs: Add a source line annotation for the given instruction in the given
  method. Note that if the method does not have line number information,
  then no source line annotation will be added.
  
  @param classContext
  the ClassContext
  @param methodGen
  the method being visited
  @param sourceFile
  source file the method is defined in
  @param handle
  the InstructionHandle containing the visited instruction
  @return this object