I tried out the AMPL statements that you show, with some made-up test data, but I did not observe the “0 constraints” that you are seeing. So, the error must be originating in some other part of your model and data. Some possibilities are that:
- CHOICE_SETS is an empty set, due to some error in reading the data for it.
- Your constraint “effort_constraint” is not being actually read by AMPL.
If you need more help, try replying with your complete model and data file uploaded. (Judging from the message “Substitution eliminates 1822104 variables,” your set “effort” may be very large; if so, it may be helpful to create a smaller data example for testing.)