If it works in vim it should work in neovim?
Nvim tracks all Vim patches[1]. _Only_ the job-control API differs. All other Vim patches are merged into Nvim reguarly, including new Vimscript features like partials, lambdas, etc.
Nearly all 7.4.x patches (except for job-control) have been merged:
https://neovim.io/doc/reports/vimpatch/
Hundreds of 8.0.x patches have been merged also, but they won't be in that report until we finish the last couple 7.4.x patches.
[1] https://github.com/neovim/neovim/wiki/Merging-patches-from-u...
Lots of errors. Most common seems to be:
E117: Unknown function: funcref
And similar.