Princess: fix usage of ambiguous methods for Scala types.

Author: kfriedberger

src/org/sosy_lab/java_smt/solvers/princess/PrincessFormulaCreator.java

@@ -11,7 +11,6 @@
 import static com.google.common.base.Preconditions.checkArgument;
 import static org.sosy_lab.java_smt.api.QuantifiedFormulaManager.Quantifier.EXISTS;
 import static org.sosy_lab.java_smt.api.QuantifiedFormulaManager.Quantifier.FORALL;
-import static org.sosy_lab.java_smt.solvers.princess.PrincessEnvironment.toITermSeq;
 import static org.sosy_lab.java_smt.solvers.princess.PrincessEnvironment.toSeq;
 import static scala.collection.JavaConverters.asJava;
 import static scala.collection.JavaConverters.asJavaCollection;
@@ -547,15 +546,19 @@ private <R> R visitQuantifier(FormulaVisitor<R> visitor, BooleanFormula f, IQuan
 
     // substitute the bound variable with index 0 with a new variable, and un-shift the remaining
     // de-Bruijn indices, such that the next nested bound variable has index 0.
-    IFormula substitutedBody = IFormula.subst(body, toITermSeq(substitutionVariable).toList(), -1);
+    IFormula substitutedBody = IFormula.subst(body, asScalaList(substitutionVariable), -1);
 
     return visitor.visitQuantifier(
         f,
         quantifier,
-        List.of(encapsulateWithTypeOf(substitutionVariable)),
+        ImmutableList.of(encapsulateWithTypeOf(substitutionVariable)),
         encapsulateBoolean(substitutedBody));
   }
 
+  private static scala.collection.immutable.List<ITerm> asScalaList(ITerm substitutionVariable) {
+    return scala.collection.immutable.List$.MODULE$.empty().$colon$colon(substitutionVariable);
+  }
+
   /**
    * Get a fresh variable name for the given formula. We compute the same variable name for the same
    * body, such that a user gets the same substituted body when visiting a quantified formulas