* Fix crash in type resolution in JS IIFEs
We recognise IIFEs as JS special assignment initialisers, but not as
containers otherwise. That means that IIFEs will not have a symbol
unless they have an *outside* assignment.
The permanent fix will be to make IIFEs a container, based on the
containership of the value that they return. This fix does not do that;
it just makes type resolution return undefined instead of crashing.
* Comment the IIFE-fix line