Hi everyone,

I’m having a problem with JuMP/Juniper.

For first I create an optimization model

```
m = Model(Juniper.Optimizer)
set_optimizer_attribute(m, "nl_solver", Ipopt.Optimizer)
set_optimizer_attribute(m, "mip_solver", Cbc.Optimizer)
```

and then I define all the variables and constraints. Up to this point everithing is ok.

Successively, I run the optimization. The solver starts to print its outputs in the REPL until it ends, since the convergence is reached.

```
EXIT: Optimal Solution Found.
Status of relaxation: LOCALLY_SOLVED
```

However, immediatly after that, the following error appears:

```
ERROR: type DataType has no field optimizer_constructor
Stacktrace:
[1] getproperty(::Type{T} where T, ::Symbol) at .\Base.jl:28
[2] generate_mip(::Juniper.Optimizer, ::Juniper.JuniperProblem, ::Array{Float64,1}, ::Juniper.TabuList, ::Float64) at C:\Users\user1\.julia\packages\Juniper\Hm6I1\src\fpump.jl:9
[3] fpump(::Juniper.Optimizer, ::Juniper.JuniperProblem) at C:\Users\user1\.julia\packages\Juniper\Hm6I1\src\fpump.jl:360
[4] optimize!(::Juniper.Optimizer) at C:\Users\user1\.julia\packages\Juniper\Hm6I1\src\MOI_wrapper\MOI_wrapper.jl:413
[5] optimize!(::MathOptInterface.Bridges.LazyBridgeOptimizer{Juniper.Optimizer}) at C:\Users\user1\.julia\packages\MathOptInterface\bygN7\src\Bridges\bridge_optimizer.jl:239
[6] optimize!(::MathOptInterface.Utilities.CachingOptimizer{MathOptInterface.AbstractOptimizer,MathOptInterface.Utilities.UniversalFallback{MathOptInterface.Utilities.Model{Float64}}}) at C:\Users\user1\.julia\packages\MathOptInterface\bygN7\src\Utilities\cachingoptimizer.jl:189
[7] optimize!(::Model, ::Nothing; bridge_constraints::Bool, ignore_optimize_hook::Bool, kwargs::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at C:\Users\user1\.julia\packages\JuMP\YXK4e\src\optimizer_interface.jl:131
[8] optimize! at C:\Users\user1\.julia\packages\JuMP\YXK4e\src\optimizer_interface.jl:107 [inlined] (repeats 2 times)
[9] top-level scope at none:0
```

and the optimization results are not provided.

Unfortunately, I have no idea what it means and looking on the web I did not find anything useful.

Does anyone know what is going wrong?