Stop unfolding if grammar is closed, which it is for CEGLESS

src/main/scala/leon/synthesis/rules/CegisLike.scala

@@ -561,6 +561,10 @@ abstract class CEGISLike[T <% Typed](name: String) extends Rule(name) {
 
               solver1.assertCnstr(clause)
               solver2.assertCnstr(clause)
+
+              if (clauses.isEmpty) {
+                unfolding = maxUnfoldings
+              }
             }
 
             // Compute all programs that have not been excluded yet

src/main/scala/leon/synthesis/rules/Cegless.scala

@@ -13,7 +13,7 @@ import utils._
 import utils.ExpressionGrammars._
 
 case object CEGLESS extends CEGISLike[Label[String]]("CEGLESS") {
-  override val maxUnfoldings = 3;
+  override val maxUnfoldings = 1000;
 
   def getGrammar(sctx: SynthesisContext, p: Problem) = {