Untaken Branch Affects whether package can be loaded

[Keno]

julia> if isdefined(:Gadfly)
           const g = Gadfly
           for x in (1,)
           end
       end

julia> using Gadfly
ERROR: invalid module path (Gadfly does not name a module)

Without the first expression Gadfly loads just fine.

[JeffBezanson]

This is basically #2586 --- the for loop forces compilation, which forces the binding for Gadfly to be resolved in const g = Gadfly.

[JeffBezanson]

Hmm, maybe I can fix this since the binding location can stay the same, and allow loading the module as long as the variable remains undefined.

[Keno]

Awesome!