Get slots in trans_tag using Semant tables. Closes #133.

src/test/run-pass/generic-tag-values.rs

@@ -0,0 +1,23 @@
+// -*- rust -*-
+
+type noption[T] = tag(some(T));
+
+fn main() {
+  let noption[int] nop = some[int](5);
+  alt (nop) {
+    case (some[int](n)) {
+      log n;
+      check (n == 5);
+    }
+  }
+
+  let noption[tup(int, int)] nop2 = some[tup(int, int)](tup(17, 42));
+  alt (nop2) {
+    case (some[tup(int, int)](t)) {
+      log t._0;
+      log t._1;
+      check (t._0 == 17);
+      check (t._1 == 42);
+    }
+  }
+}