LocalDFG Vars Facs are `OrderedDict{Symbol, NONCONCRETE}`

[dehann]

TAC

• achieve full type stability / make all concrete

Possible approaches:

• Perhaps use Dict of Dict or equivalent
• something better

[Affie]

For general functions such as getVariable, function barriers might be our only hope as we do not know the type in advanced.
We can look into using something like a VariableType trait and getVariable(::Type{T}, dfg, label), but we might just be building dynamic dispatch then.