[514590] Support observed properties for checked statements
diff --git a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/QVTimperative.xtext b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/QVTimperative.xtext
index 5ee23a1..f2b25a5 100644
--- a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/QVTimperative.xtext
+++ b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/QVTimperative.xtext
@@ -37,7 +37,8 @@
 
 CommitStatementCS returns StatementCS:	NewStatementCS | SetStatementCS;
 	
-CheckStatementCS: 'check' ownedCondition=ExpCS ';';
+CheckStatementCS: ('observe' observedProperties+=PathNameCS (',' observedProperties+=PathNameCS)*)?
+	'check' ownedCondition=ExpCS ';';
 	
 ControlStatementCS returns MappingStatementCS: AddStatementCS | MappingCallCS | MappingLoopCS;