2.8.2: objective variable replaced by constant, but still occuring in minimize expression

[ptal]

Hi,

On the spot5.mzn / 404.dzn instance, given constraint objective = 136; in the model, the flattening phase outputs:

solve :: seq_search([int_search(p,first_fail,indomain_min,complete),int_search([136],input_order,indomain_min,complete)]) minimize objective;

But it replaced the variable objective by its value and therefore minimize objective fails to parse because it is not declared anymore.

This bug was discovered when using mzn-bench to check the solutions produced by my solver.

spot5.zip