accumulation: support single track mode for more cases

prism/src/parser/ast/Expression.java

@@ -1015,10 +1015,12 @@ public abstract class Expression extends ASTElement
 		try {
 			ASTTraverse astt = new ASTTraverse()
 			{
-				public Object visit(ExpressionTemporal expr)
-				{
-					return null;
-				}
+				public Object visit(ExpressionTemporal expr) { return null; }
+				public Object visit(ExpressionProb expr)     { return null; }
+				public Object visit(ExpressionReward expr)   { return null; }
+				public Object visit(ExpressionSS expr)       { return null; }
+				public Object visit(ExpressionForAll expr)   { return null; }
+				public Object visit(ExpressionExists expr)   { return null; }
 				public Object visit(ExpressionAccumulation accexp) throws PrismLangException
 				{
 					throw new PrismLangException("Found accumulation here!", accexp);