I've recently started to read code on the next branch, and found that Flow is used to check types. I think it's really a wise decision to statically analyse types for more reliable code base.

However, I found that vim-flow reported errors. The errors occur in Flow 0.30.0, which I installed in my global env. I understand it's not an urgent issue and it's completely okay for now to stick to the current version, but it's always good to get prepared.

FYI, errors are about string interpolation for Maybe type. An example is listed below:

src/compiler/codegen/index.js:77
 77:   return `(${exp})?${genElement(el)}:${genElse(el)}`
                  ^^^ undefined. This type cannot be added to
 77:   return `(${exp})?${genElement(el)}:${genElse(el)}`
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ string

If you don't mind, I'd like to help this issue to be resolved. Please feel free to drop a comment.
Cheers!