Error: expr-visitor.sml 787.5.

[pdmatei]

Hello,
I have just downloaded the project, installed latest Ruby, Z3 and SML, then ran "make". I get the following error:
Error: expr-visitor.sml 787.5.
unresolved flex record (need to know the names of ALL the fields
in this context)
type: {current:'Y ref, outer:'X; 'Z}
Compilation failed.
make: *** [smlnj] Error 1

I looked at the definition:
fun copy_ctx ctx =
{outer = #outer ctx, current = copy_ref $ #current ctx}

which probably creates the issue, but I have almost 0 experience with SML and am having real trouble finding a fix. Could you help me out please?

We are considering using TiML for a performance verification task on middlebox code - if we can manage to make it work.