If there's an unknown record field X.y, the error message says that record field X cannot be found. This should be an easy fix in the parsing/regex.
# Unformatted Error Output:
# File "compiler/js_of_ocaml.ml", line 67, characters 6-19:
# Error: Unbound record field CompileArg.wrap_with_fun
ERROR compiler/js_of_ocaml.ml:67 6-19
64 ┆ ; output_file
65 ┆ ; params
66 ┆ ; static_env
67 ┆ ; wrap_with_fun
68 ┆ ; dynlink
69 ┆ ; linkall
70 ┆ ; toplevel
Record field CompileArg; can't be found in any record type.