Support nested parameters, but fails with non-static values (see FoodsBull, ASg kind.g).

testsuite/lpgf/ScratchCnc.gf

@@ -0,0 +1,18 @@
+concrete ScratchCnc of Scratch = {
+  param
+    R = R1 | R2 ;
+    P = PR R Q | PP ;
+    Q = Q1 | Q2 ;
+  lincat
+    S = Str ;
+    F = { p : P => Str } ;
+  lin
+    f1 = f2 ;
+    f2 = { p = table {
+      PR R1 Q1 => "R1 Q1" ;
+      PR R1 Q2 => "R1 Q2" ;
+      PR R2 _ => "R2 _" ;
+      PP => "PP"
+     } } ;
+    FtoS f = f.p ! PR R1 Q2 ;
+}