VDM-SL traces fail when referencing state data

[nickbattle]

Combinatorial traces can reference state data in VDM-SL (just as they can reference instance variables in VDM++). But there is a bug which prevents state values from being populated in the runtime environment. So the following specification has no type errors, but at runtime the "s" state variable cannot be found.

state Sigma of
    s : nat
    init z == z = mk_Sigma(1)
end

traces
    T: let x = s in op(x)     -- "s" is not found at test expansion

The fix will be available in 2.0.2.

[nickbattle]

Fixed in ncb/development. I forgot the "#" in the "fixes #252", sorry.

See commit ccb8922.