Real World Ocaml "instanceof" issue

[dvisztempacct]

I tried throwing this page at reason-tools:

https://realworldocaml.org/v1/en/html/objects.html

Here is one of the code listings:

After reason-tools does its job:

It looks like RWO uses infix notation to invoke instanceof but reason-tools doesn't know this and thinks its an invocation of s instead.