I must be missing something very fundamental about the new type system called HELGINS, it just doesn't seem to work for me.
I used to use the "traditional" type system, and everything worked just fine: types were recognized, appropriate actions were generated, etc. Then I simply removed the old rules and replaced them with the ones created in HELGINS (just inference rules for now).
Now, the "Show type" context menu action that used to show the correct types of my nodes, just displays a message: "Status ERROR COMPOSITE, 1: no type". Obviously the editor displays the nodes underlined with red and I can't do anything useful with them. However, the other menu action on the bottom called "View type" shows the correct inferred type, so it does work somehow. Also, CtrlShiftR also jumps from my concept to the correct rule.
I'm puzzled. Is there something else I should do to make the new type system work for me, besides creating the rules and generating/compiling the language? I must admit, the documentation that comes with MPS isn't very helpful at this.