Names for variable bounds

[odow]

@mlubin suggested that jump-dev/GLPK.jl#101 (comment)

I'm proposing to make setting ConstraintName on SingleVariable constraint into an error. This wouldn't change lookups otherwise.

To look up the bound on a variable, you first look up the variable. The index of the variable gives you the index of the bound constraint.

Is this something for MOI 0.10?

[blegat]

Yes, there is a similar issue with Mosek:
https://github.com/JuliaOpt/MosekTools.jl/blob/2474e1798af4fb2f342c2228a34e2c0430aafe17/src/MosekTools.jl#L82-L84

[mlubin]

Yes, I'm still in support of this.

[odow]

Are we still in support of this change? It would simplify wrappers, but most wrappers are already written.

[mlubin]

I'd say so. Names on variable bounds don't make much sense from the POV of any solver.

[blegat]

Yes, I'd support changing this. We should define an error for this and check that the solvers now thro that error, e.g., in basic_constraint_test