Is there a reason to use `@expression`? I think it's redundant

Specific Domains Optimization (Mathematical)
,
9

Is this a bug?

julia> import JuMP

julia> model = JuMP.Model();

julia> x = map(_ -> JuMP.@variable(model), 1) # returns a SCALAR
_[1]

julia> ndims(x), ndims(1)
(0, 0)

julia> map(_ -> JuMP.@variable(model), x) # returns a Vector???
1-element Vector{JuMP.VariableRef}:
 _[2]

I think the last return should be _[2] solely, not wrapped in a Vector.
Yes, surely I think _[2] should be the expected return, otherwise duplicating the following:

julia> model = JuMP.Model();

julia> x = map(_ -> JuMP.@variable(model), 1)
_[1]

julia> map(_ -> JuMP.@variable(model), [x])
1-element Vector{JuMP.VariableRef}:
 _[2]

The julia’s behavior is sane:

julia> map(_ -> 1, 2)
1

julia> map(_ -> 1, [2])
1-element Vector{Int64}:
 1