Don't do strategy generation with symbolic engines if there are duplicate actions.

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@7605 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/prism/Prism.java

@@ -2679,6 +2679,13 @@ public class Prism extends PrismComponent implements PrismSettingsListener
 				setEngine(Prism.EXPLICIT);
 			}
 		}
+		// Compatibility check
+		if (genStrat && currentModelType.nondeterministic() && !getExplicit()) {
+			if (!((NondetModel) currentModel).areAllChoiceActionsUnique())
+				throw new PrismException("Cannot generate strategies with the current engine "
+						+ "because some state of the model do not have unique action labels for each choice. "
+						+ "Either switch to the explicit engine or add more action labels to the model");
+		}
 
 		try {
 			// Build model, if necessary