Minor Changes

Author: rcosta358

liquidjava-verifier/src/main/java/liquidjava/processor/refinement_checker/general_checkers/OperationsChecker.java

@@ -16,6 +16,8 @@
 import liquidjava.utils.constants.Ops;
 import liquidjava.utils.constants.Types;
 import liquidjava.rj_language.Predicate;
+import liquidjava.rj_language.ast.LiteralNull;
+
 import org.apache.commons.lang3.NotImplementedException;
 import spoon.reflect.code.BinaryOperatorKind;
 import spoon.reflect.code.CtAssignment;
@@ -221,7 +223,7 @@ private Predicate getOperationRefinements(CtBinaryOperator<?> operator, CtVariab
                 return new Predicate();
             }
             if (l.getValue() == null)
-                return new Predicate("null", element);
+                return new Predicate(new LiteralNull());
 
             return new Predicate(l.getValue().toString(), element);
 

liquidjava-verifier/src/main/java/liquidjava/rj_language/Predicate.java

@@ -76,7 +76,6 @@ public Predicate(String ref, CtElement element, String prefix) throws LJError {
         }
     }
 
-    /** Create a predicate with the expression true */
     public Predicate(Expression e) {
         exp = e;
     }