Missing comprehension elements' indetifier

[ndangtt]

example.zip

When I run conjure solve for the attached model and Essence param file, I get the following error messages:

Error:
    Savile Row stdout: ERROR: Identifier not defined: instance

    Savile Row stderr: ERROR: Failed type checking after substituting in lettings.

    Savile Row exit-code: 1

The reason seems to be that in the generated .eprime model, some of the list comprehension identifiers instance are missing. The corresponding lines in the Essence model are lines 46-47:

   total_solving_time = sum([sum([schedule(i)[time] | i:int(1..n_streamliners), i<instanceFirstSolve]) + solving_time((schedule(instanceFirstSolve)[streamliner],instance)) | instance : instances,
    letting instanceFirstSolve be min([index | (index,st) <- schedule, solving_time((st[streamliner],instance))<=st[time]])])