How do I fix incremental compilation warning?

How do I fix the following incremental compilation issue (or is it OK)?

WARNING: Method definition latex(IO, Markdown.LaTeX) in module Markdown at 
...v1.5/Markdown/src/IPython/IPython.jl:28 overwritten in module 
.../Weave/BarbQ/src/WeaveMarkdown/markdown.jl:10.

  ** incremental compilation may be fatally broken for this module **

Thank you very much