fix: Loading of model with datatypes crashes

- Changed invalid cast from MClass to MClassifier

Author: h-man2

use-core/src/main/java/org/tzi/use/analysis/coverage/AbstractCoverageVisitor.java

@@ -19,11 +19,11 @@
 
 package org.tzi.use.analysis.coverage;
 
-import java.util.Stack;
-
 import org.tzi.use.uml.mm.*;
 import org.tzi.use.uml.ocl.expr.*;
 
+import java.util.Stack;
+
 /**
  * Abstract visitor implementation.
  * 
@@ -78,7 +78,7 @@ public void visitAsType(ExpAsType exp) {
 	@Override
 	public void visitAttrOp(ExpAttrOp exp) {
 		exp.objExp().processWithVisitor(this);
-		addAttributeCoverage((MClass) exp.objExp().type(), exp.attr());
+		addAttributeCoverage((MClassifier) exp.objExp().type(), exp.attr());
 	}
 
 	@Override