diff -uNr gnome-calculator-3.34.1/gcalc/gcalc-ggroup.vala gnome-calculator-3.34.1_fix/gcalc/gcalc-ggroup.vala
--- gnome-calculator-3.34.1/gcalc/gcalc-ggroup.vala	2019-10-07 08:35:20.000000000 +0200
+++ gnome-calculator-3.34.1_fix/gcalc/gcalc-ggroup.vala	2020-03-25 21:54:25.238572978 +0100
@@ -24,13 +24,13 @@
   public override string to_string () {
     string s = "";
     switch (level) {
-      case ONE:
+      case Group.Level.ONE:
         s = "(";
         break;
-      case TWO:
+      case Group.Level.TWO :
         s = "[";
         break;
-      case THREE:
+      case Group.Level.THREE:
         s = "{";
         break;
     }
@@ -38,13 +38,13 @@
       s += e.to_string ();
     }
     switch (level) {
-      case ONE:
+      case Group.Level.ONE:
         s += ")";
         break;
-      case TWO:
+      case Group.Level.TWO :
         s += "]";
         break;
-      case THREE:
+      case Group.Level.THREE:
         s += "}";
         break;
     }