[500369] Support SetStatement

31 files changed, 483 insertions, 526 deletions

diff --git a/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/analyzer/QVTiAS2CGVisitor.java b/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/analyzer/QVTiAS2CGVisitor.java
index fca2e1dd9..17d9b49d9 100644
--- a/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/analyzer/QVTiAS2CGVisitor.java
+++ b/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/analyzer/QVTiAS2CGVisitor.java
@@ -105,6 +105,7 @@ import org.eclipse.qvtd.pivot.qvtbase.utilities.QVTbaseUtil;
 import org.eclipse.qvtd.pivot.qvtimperative.Area;
 import org.eclipse.qvtd.pivot.qvtimperative.Assignment;
 import org.eclipse.qvtd.pivot.qvtimperative.BottomPattern;
+import org.eclipse.qvtd.pivot.qvtimperative.BottomStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionVariable;
@@ -117,10 +118,8 @@ import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingStatement;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.OppositePropertyAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.Statement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.VariablePredicate;
@@ -392,10 +391,7 @@ public class QVTiAS2CGVisitor extends AS2CGVisitor implements QVTimperativeVisit
 			for (@NonNull BottomPattern pBottomPattern : pBottomPatterns) {
 				List<@NonNull Assignment> assignment = ClassUtil.nullFree(pBottomPattern.getAssignment());
 				for (@NonNull Assignment pAssignment : assignment) {
-					if (pAssignment instanceof PropertyAssignment) {
-						cgPropertyAssignments.add(doVisit(CGPropertyAssignment.class, pAssignment));
-					}
-					else if (pAssignment instanceof ConnectionAssignment) {
+					if (pAssignment instanceof ConnectionAssignment) {
 						cgConnectionAssignments.add(doVisit(CGConnectionAssignment.class, pAssignment));
 					}
 					else {
@@ -709,6 +705,11 @@ public class QVTiAS2CGVisitor extends AS2CGVisitor implements QVTimperativeVisit
 	}
 
 	@Override
+	public @Nullable CGNamedElement visitBottomStatement(@NonNull BottomStatement object) {
+		return visitStatement(object);
+	}
+
+	@Override
 	public @Nullable CGNamedElement visitConnectionAssignment(@NonNull ConnectionAssignment asConnectionAssignment) {
 		Variable asVariable = asConnectionAssignment.getTargetVariable();
 		if (asVariable == null) {
@@ -913,21 +914,77 @@ public class QVTiAS2CGVisitor extends AS2CGVisitor implements QVTimperativeVisit
 	}
 
 	@Override
-	public @Nullable CGNamedElement visitNavigationAssignment(@NonNull NavigationAssignment asNavigationAssignment) {
-		Transformation asTransformation = ClassUtil.nonNullModel(QVTbaseUtil.getContainingTransformation(asNavigationAssignment));
+	public @Nullable CGNamedElement visitPattern(@NonNull Pattern object) {
+		return visiting(object);
+	}
+
+	@Override
+	public @Nullable CGIfExp visitPredicate(@NonNull Predicate asPredicate) {
+		CGIfExp cgPredicate = CGModelFactory.eINSTANCE.createCGIfExp();
+		cgPredicate.setTypeId(analyzer.getTypeId(TypeId.BOOLEAN));
+		cgPredicate.setRequired(true);
+		OCLExpression asConditionExpression = asPredicate.getConditionExpression();
+		assert asConditionExpression != null;
+		cgPredicate.setCondition(doVisit(CGValuedElement.class, asConditionExpression));
+		CGConstantExp cgElse = analyzer.createCGConstantExp(asConditionExpression, analyzer.getBoolean(false));
+		setAst(cgElse, asConditionExpression);
+		cgElse.setTypeId(analyzer.getTypeId(TypeId.BOOLEAN));
+		cgElse.setRequired(true);
+		cgPredicate.setElseExpression(cgElse);
+		return cgPredicate;
+	}
+
+	/*	@Override
+	public @Nullable CGNamedElement visitMiddlePropertyAssignment(@NonNull MiddlePropertyAssignment asPropertyAssignment) {
+//		Property asProperty = ClassUtil.nonNullModel(asPropertyAssignment.getTargetProperty());
+		CGMiddlePropertyAssignment cgPropertyAssignment = QVTiCGModelFactory.eINSTANCE.createCGMiddlePropertyAssignment();
+//		setPivot(cgPropertyAssignment, asPredicate);
+		cgPropertyAssignment.setSlotValue(doVisit(CGValuedElement.class, asPropertyAssignment.getSlotExpression()));
+		Property asProperty = asPropertyAssignment.getTargetProperty();
+		cgPropertyAssignment.setReferredProperty(asProperty);
+//		cgPredicate.setName(asPredicate.getName());
+		cgPropertyAssignment.setTypeId(analyzer.getTypeId(TypeId.OCL_VOID));
+//		cgMappingCallBinding.setValueName(localnameasMappingCallBinding.getBoundVariable().getName());
+		cgPropertyAssignment.setInitValue(doVisit(CGValuedElement.class, asPropertyAssignment.getValue()));
+		EStructuralFeature eStructuralFeature = (EStructuralFeature) asProperty.getESObject();
+		if (eStructuralFeature != null) {
+			try {
+				genModelHelper.getGetAccessor(eStructuralFeature);
+				cgPropertyAssignment.setEStructuralFeature(eStructuralFeature);
+			} catch (GenModelException e) {
+			}
+		}
+		return cgPropertyAssignment;
+	} */
+
+	@Override
+	public @Nullable CGNamedElement visitRealizedVariable(@NonNull RealizedVariable object) {
+		//		CGExecutorType cgExecutorType = analyzer.createExecutorType(pTypeExp.getReferredType());
+		//		cgTypeExp.setExecutorType(cgExecutorType);
+		return visiting(object);
+	}
+
+	@Override
+	public @Nullable CGNamedElement visitRule(@NonNull Rule object) {
+		return visiting(object);
+	}
+
+	@Override
+	public @Nullable CGNamedElement visitSetStatement(@NonNull SetStatement asSetStatement) {
+		Transformation asTransformation = ClassUtil.nonNullModel(QVTbaseUtil.getContainingTransformation(asSetStatement));
 		QVTiTransformationAnalysis transformationAnalysis = analyzer.getCodeGenerator().getTransformationAnalysis(asTransformation);
-		Integer cacheIndex = transformationAnalysis.getCacheIndex(asNavigationAssignment);
+		Integer cacheIndex = transformationAnalysis.getCacheIndex(asSetStatement);
 		if (cacheIndex != null) {
 			//			Property asProperty = ClassUtil.nonNullModel(asPropertyAssignment.getTargetProperty());
 			CGMiddlePropertyAssignment cgPropertyAssignment = QVTiCGModelFactory.eINSTANCE.createCGMiddlePropertyAssignment();
-			setAst(cgPropertyAssignment, asNavigationAssignment);
-			cgPropertyAssignment.setSlotValue(doVisit(CGValuedElement.class, asNavigationAssignment.getSlotExpression()));
-			Property asProperty = QVTimperativeUtil.getTargetProperty(asNavigationAssignment);
+			setAst(cgPropertyAssignment, asSetStatement);
+			cgPropertyAssignment.setSlotValue(doVisit(CGValuedElement.class, asSetStatement.getSlotExpression()));
+			Property asProperty = QVTimperativeUtil.getTargetProperty(asSetStatement);
 			cgPropertyAssignment.setReferredProperty(asProperty);
 			//			cgPredicate.setName(asPredicate.getName());
 			cgPropertyAssignment.setTypeId(analyzer.getTypeId(TypeId.OCL_VOID));
 			//			cgMappingCallBinding.setValueName(localnameasMappingCallBinding.getBoundVariable().getName());
-			cgPropertyAssignment.setInitValue(doVisit(CGValuedElement.class, asNavigationAssignment.getValue()));
+			cgPropertyAssignment.setInitValue(doVisit(CGValuedElement.class, asSetStatement.getValue()));
 			EStructuralFeature eStructuralFeature = (EStructuralFeature) asProperty.getESObject();
 			if (eStructuralFeature != null) {
 				try {
@@ -940,8 +997,8 @@ public class QVTiAS2CGVisitor extends AS2CGVisitor implements QVTimperativeVisit
 			return cgPropertyAssignment;
 		}
 		else {
-			Property asTargetProperty = QVTimperativeUtil.getTargetProperty(asNavigationAssignment);
-			LibraryProperty libraryProperty = metamodelManager.getImplementation(asNavigationAssignment, null, asTargetProperty);
+			Property asTargetProperty = QVTimperativeUtil.getTargetProperty(asSetStatement);
+			LibraryProperty libraryProperty = metamodelManager.getImplementation(asSetStatement, null, asTargetProperty);
 			CGPropertyAssignment cgPropertyAssignment = null;
 			if (isEcoreProperty(libraryProperty)) {
 				EStructuralFeature eStructuralFeature = (EStructuralFeature) asTargetProperty.getESObject();
@@ -974,13 +1031,13 @@ public class QVTiAS2CGVisitor extends AS2CGVisitor implements QVTimperativeVisit
 			if (cgPropertyAssignment == null) {
 				cgPropertyAssignment = QVTiCGModelFactory.eINSTANCE.createCGPropertyAssignment();
 			}
-			setAst(cgPropertyAssignment, asNavigationAssignment);
-			cgPropertyAssignment.setSlotValue(doVisit(CGValuedElement.class, asNavigationAssignment.getSlotExpression()));
+			setAst(cgPropertyAssignment, asSetStatement);
+			cgPropertyAssignment.setSlotValue(doVisit(CGValuedElement.class, asSetStatement.getSlotExpression()));
 			cgPropertyAssignment.setReferredProperty(asTargetProperty);
 			//		cgPredicate.setName(asPredicate.getName());
 			cgPropertyAssignment.setTypeId(analyzer.getTypeId(TypeId.OCL_VOID));
 			//		cgMappingCallBinding.setValueName(localnameasMappingCallBinding.getBoundVariable().getName());
-			cgPropertyAssignment.setInitValue(doVisit(CGValuedElement.class, asNavigationAssignment.getValue()));
+			cgPropertyAssignment.setInitValue(doVisit(CGValuedElement.class, asSetStatement.getValue()));
 
 			CGExecutorProperty cgExecutorProperty = analyzer.createExecutorProperty(asTargetProperty);
 			cgPropertyAssignment.setExecutorProperty(cgExecutorProperty);
@@ -989,72 +1046,6 @@ public class QVTiAS2CGVisitor extends AS2CGVisitor implements QVTimperativeVisit
 	}
 
 	@Override
-	public @Nullable CGNamedElement visitPattern(@NonNull Pattern object) {
-		return visiting(object);
-	}
-
-	@Override
-	public @Nullable CGIfExp visitPredicate(@NonNull Predicate asPredicate) {
-		CGIfExp cgPredicate = CGModelFactory.eINSTANCE.createCGIfExp();
-		cgPredicate.setTypeId(analyzer.getTypeId(TypeId.BOOLEAN));
-		cgPredicate.setRequired(true);
-		OCLExpression asConditionExpression = asPredicate.getConditionExpression();
-		assert asConditionExpression != null;
-		cgPredicate.setCondition(doVisit(CGValuedElement.class, asConditionExpression));
-		CGConstantExp cgElse = analyzer.createCGConstantExp(asConditionExpression, analyzer.getBoolean(false));
-		setAst(cgElse, asConditionExpression);
-		cgElse.setTypeId(analyzer.getTypeId(TypeId.BOOLEAN));
-		cgElse.setRequired(true);
-		cgPredicate.setElseExpression(cgElse);
-		return cgPredicate;
-	}
-
-	/*	@Override
-	public @Nullable CGNamedElement visitMiddlePropertyAssignment(@NonNull MiddlePropertyAssignment asPropertyAssignment) {
-//		Property asProperty = ClassUtil.nonNullModel(asPropertyAssignment.getTargetProperty());
-		CGMiddlePropertyAssignment cgPropertyAssignment = QVTiCGModelFactory.eINSTANCE.createCGMiddlePropertyAssignment();
-//		setPivot(cgPropertyAssignment, asPredicate);
-		cgPropertyAssignment.setSlotValue(doVisit(CGValuedElement.class, asPropertyAssignment.getSlotExpression()));
-		Property asProperty = asPropertyAssignment.getTargetProperty();
-		cgPropertyAssignment.setReferredProperty(asProperty);
-//		cgPredicate.setName(asPredicate.getName());
-		cgPropertyAssignment.setTypeId(analyzer.getTypeId(TypeId.OCL_VOID));
-//		cgMappingCallBinding.setValueName(localnameasMappingCallBinding.getBoundVariable().getName());
-		cgPropertyAssignment.setInitValue(doVisit(CGValuedElement.class, asPropertyAssignment.getValue()));
-		EStructuralFeature eStructuralFeature = (EStructuralFeature) asProperty.getESObject();
-		if (eStructuralFeature != null) {
-			try {
-				genModelHelper.getGetAccessor(eStructuralFeature);
-				cgPropertyAssignment.setEStructuralFeature(eStructuralFeature);
-			} catch (GenModelException e) {
-			}
-		}
-		return cgPropertyAssignment;
-	} */
-
-	@Override
-	public @Nullable CGNamedElement visitOppositePropertyAssignment(@NonNull OppositePropertyAssignment asPropertyAssignment) {
-		return visitNavigationAssignment(asPropertyAssignment);
-	}
-
-	@Override
-	public @Nullable CGNamedElement visitPropertyAssignment(@NonNull PropertyAssignment asPropertyAssignment) {
-		return visitNavigationAssignment(asPropertyAssignment);
-	}
-
-	@Override
-	public @Nullable CGNamedElement visitRealizedVariable(@NonNull RealizedVariable object) {
-		//		CGExecutorType cgExecutorType = analyzer.createExecutorType(pTypeExp.getReferredType());
-		//		cgTypeExp.setExecutorType(cgExecutorType);
-		return visiting(object);
-	}
-
-	@Override
-	public @Nullable CGNamedElement visitRule(@NonNull Rule object) {
-		return visiting(object);
-	}
-
-	@Override
 	public @Nullable CGNamedElement visitStatement(@NonNull Statement object) {
 		return visiting(object);
 	}
diff --git a/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/java/QVTiCG2JavaVisitor.java b/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/java/QVTiCG2JavaVisitor.java
index ded250000..96cf4d679 100644
--- a/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/java/QVTiCG2JavaVisitor.java
+++ b/plugins/org.eclipse.qvtd.codegen/src/org/eclipse/qvtd/codegen/qvti/java/QVTiCG2JavaVisitor.java
@@ -100,15 +100,11 @@ import org.eclipse.qvtd.pivot.qvtbase.Transformation;
 import org.eclipse.qvtd.pivot.qvtbase.TypedModel;
 import org.eclipse.qvtd.pivot.qvtbase.analysis.DomainUsage;
 import org.eclipse.qvtd.pivot.qvtimperative.Area;
-import org.eclipse.qvtd.pivot.qvtimperative.Assignment;
-import org.eclipse.qvtd.pivot.qvtimperative.BottomPattern;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionVariable;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.evaluation.QVTiTransformationAnalysis;
 import org.eclipse.qvtd.pivot.qvtimperative.utilities.QVTimperativeUtil;
 import org.eclipse.qvtd.runtime.evaluation.AbstractInvocation;
@@ -188,24 +184,6 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 	}
 
 	protected void doAddRealization(@NonNull CGRealizedVariable cgRealizedVariable) {
-		RealizedVariable pRealizedVariable = (RealizedVariable)cgRealizedVariable.getAst();
-		Area pArea = QVTimperativeUtil.getContainingArea(pRealizedVariable);
-		if (pArea != null) {
-			BottomPattern pBottomPattern = pArea.getBottomPattern();
-			if (pBottomPattern != null) {
-				for (@NonNull Assignment pAssignment : ClassUtil.nullFree(pBottomPattern.getAssignment())) {
-					if (pAssignment instanceof PropertyAssignment) {
-						Property pProperty = ((PropertyAssignment)pAssignment).getTargetProperty();
-						if (pProperty != null) {
-							Property pOppositeProperty = pProperty.getOpposite();
-							if ((pOppositeProperty != null) && pOppositeProperty.isIsComposite()) {
-								// FIXME must check for null asssignment and correct target								return;
-							}
-						}
-					}
-				}
-			}
-		}
 		CGTypedModel cgTypedModel = cgRealizedVariable.getTypedModel();
 		//
 		js.append(QVTiGlobalContext.MODELS_NAME);
@@ -343,10 +321,10 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		CGValuedElement cgInit = getExpression(cgPropertyAssignment.getInitValue());
 		EPackage ePackage = ClassUtil.nonNullModel(eStructuralFeature.getEContainingClass().getEPackage());
 		boolean isHazardous = false;
-		Element asNavigationAssignment = cgPropertyAssignment.getAst();
-		Mapping asMapping = QVTimperativeUtil.getContainingMapping(asNavigationAssignment);
-		if ((asMapping != null) && (asNavigationAssignment instanceof NavigationAssignment)) {
-			isHazardous = transformationAnalysis.isHazardousWrite(asMapping, (NavigationAssignment)asNavigationAssignment);
+		Element asSetStatement = cgPropertyAssignment.getAst();
+		Mapping asMapping = QVTimperativeUtil.getContainingMapping(asSetStatement);
+		if ((asMapping != null) && (asSetStatement instanceof SetStatement)) {
+			isHazardous = transformationAnalysis.isHazardousWrite(asMapping, (SetStatement)asSetStatement);
 		}
 		if (isHazardous || isIncremental) {
 			js.append("objectManager.assigned(");
@@ -370,10 +348,10 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 		CGValuedElement cgInit = getExpression(cgPropertyAssignment.getInitValue());
 		EPackage ePackage = ClassUtil.nonNullModel(eStructuralFeature.getEContainingClass().getEPackage());
 		boolean isHazardous = false;
-		Element asNavigationAssignment = cgPropertyAssignment.getAst();
-		Mapping asMapping = QVTimperativeUtil.getContainingMapping(asNavigationAssignment);
-		if ((asMapping != null) && (asNavigationAssignment instanceof NavigationAssignment)) {
-			isHazardous = transformationAnalysis.isHazardousWrite(asMapping, (NavigationAssignment)asNavigationAssignment);
+		Element asSetStatement = cgPropertyAssignment.getAst();
+		Mapping asMapping = QVTimperativeUtil.getContainingMapping(asSetStatement);
+		if ((asMapping != null) && (asSetStatement instanceof SetStatement)) {
+			isHazardous = transformationAnalysis.isHazardousWrite(asMapping, (SetStatement)asSetStatement);
 		}
 		if (isHazardous || isIncremental) {
 			js.append("objectManager.assigned(");
diff --git a/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/BasicRegion2Mapping.java b/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/BasicRegion2Mapping.java
index 6e3a8bd75..492be8464 100644
--- a/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/BasicRegion2Mapping.java
+++ b/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/BasicRegion2Mapping.java
@@ -92,8 +92,8 @@ import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
 import org.eclipse.qvtd.pivot.qvtimperative.GuardPattern;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingStatement;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.util.AbstractExtendingQVTimperativeVisitor;
 import org.eclipse.qvtd.pivot.qvtimperative.utilities.AssignmentComparator;
@@ -723,7 +723,7 @@ public class BasicRegion2Mapping extends AbstractRegion2Mapping
 		return variable;
 	}
 
-	private void createClassPropertyAssignments(@NonNull Iterable<@NonNull List<@NonNull NavigableEdge>> classAssignments) {
+	private void createClassSetStatements(@NonNull Iterable<@NonNull List<@NonNull NavigableEdge>> classAssignments) {
 		for (@NonNull List<@NonNull NavigableEdge> edges : classAssignments) {
 			for (@NonNull NavigableEdge edge : edges) {
 				Node sourceNode = edge.getSource();
@@ -731,8 +731,8 @@ public class BasicRegion2Mapping extends AbstractRegion2Mapping
 				OCLExpression slotVariableExp = createVariableExp(sourceNode);
 				Property property = edge.getProperty();
 				OCLExpression targetVariableExp = createVariableExp(targetNode);
-				PropertyAssignment propertyAssignment = QVTimperativeUtil.createPropertyAssignment(slotVariableExp, property, targetVariableExp);
-				mapping.getBottomPattern().getAssignment().add(propertyAssignment);
+				SetStatement setStatement = QVTimperativeUtil.createSetStatement((Variable) ((VariableExp)slotVariableExp).getReferredVariable(), property, targetVariableExp);
+				mapping.getOwnedStatements().add(setStatement);
 			}
 		}
 	}
@@ -1161,8 +1161,8 @@ public class BasicRegion2Mapping extends AbstractRegion2Mapping
 					valueExp = expressionCreator.getExpression(targetNode);		// FIXME debugging
 				}
 				if (valueExp != null) {
-					PropertyAssignment propertyAssignment = QVTimperativeUtil.createPropertyAssignment(slotVariableExp, property, valueExp);
-					bottomPattern.getAssignment().add(propertyAssignment);
+					SetStatement propertyAssignment = QVTimperativeUtil.createSetStatement((Variable) ((VariableExp)slotVariableExp).getReferredVariable(), property, valueExp);
+					mapping.getOwnedStatements().add(propertyAssignment);
 				}
 				else {
 					System.err.println("No assignment in " + this + " to " + slotVariableExp + "." + property);
@@ -1183,7 +1183,7 @@ public class BasicRegion2Mapping extends AbstractRegion2Mapping
 		if (classAssignments != null) {
 			pruneClassAssignments(classAssignments);
 			Collection<@NonNull List<@NonNull NavigableEdge>> values = classAssignments.values();
-			createClassPropertyAssignments(values);
+			createClassSetStatements(values);
 		}
 		@SuppressWarnings("null")
 		@NonNull EList<@NonNull Assignment> bottomAssignments = bottomPattern.getAssignment();
diff --git a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTimperativeStepperVisitor.java b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTimperativeStepperVisitor.java
index 9be5aae9b..764a4e2d1 100644
--- a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTimperativeStepperVisitor.java
+++ b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/AbstractQVTimperativeStepperVisitor.java
@@ -106,23 +106,13 @@ implements QVTimperativeVisitor<IStepper>
 	}
 
 	@Override
-	public @Nullable IStepper visitNavigationAssignment(org.eclipse.qvtd.pivot.qvtimperative.@NonNull NavigationAssignment object) {
-		return visitAssignment(object);
-	}
-
-	@Override
-	public @Nullable IStepper visitOppositePropertyAssignment(org.eclipse.qvtd.pivot.qvtimperative.@NonNull OppositePropertyAssignment object) {
-		return visitNavigationAssignment(object);
-	}
-
-	@Override
-	public @Nullable IStepper visitPropertyAssignment(org.eclipse.qvtd.pivot.qvtimperative.@NonNull PropertyAssignment object) {
-		return visitNavigationAssignment(object);
+	public @Nullable IStepper visitRealizedVariable(org.eclipse.qvtd.pivot.qvtimperative.@NonNull RealizedVariable object) {
+		return visitVariable(object);
 	}
 
 	@Override
-	public @Nullable IStepper visitRealizedVariable(org.eclipse.qvtd.pivot.qvtimperative.@NonNull RealizedVariable object) {
-		return visitVariable(object);
+	public @Nullable IStepper visitSetStatement(org.eclipse.qvtd.pivot.qvtimperative.@NonNull SetStatement object) {
+		return visitBottomStatement(object);
 	}
 
 	@Override
diff --git a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/QVTiStepperVisitor.java b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/QVTiStepperVisitor.java
index 8e6b08f01..5776d4259 100644
--- a/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/QVTiStepperVisitor.java
+++ b/plugins/org.eclipse.qvtd.debug/src/org/eclipse/qvtd/debug/stepper/QVTiStepperVisitor.java
@@ -20,6 +20,7 @@ import org.eclipse.qvtd.pivot.qvtbase.Predicate;
 import org.eclipse.qvtd.pivot.qvtbase.Transformation;
 import org.eclipse.qvtd.pivot.qvtimperative.Assignment;
 import org.eclipse.qvtd.pivot.qvtimperative.BottomPattern;
+import org.eclipse.qvtd.pivot.qvtimperative.BottomStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionVariable;
@@ -51,6 +52,11 @@ public class QVTiStepperVisitor extends AbstractQVTimperativeStepperVisitor
 	}
 
 	@Override
+	public IStepper visitBottomStatement(@NonNull BottomStatement object) {
+		return NonStepper.INSTANCE;
+	}
+
+	@Override
 	public @Nullable IStepper visitConnectionAssignment(@NonNull ConnectionAssignment object) {
 		return visitAssignment(object);
 	}
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/analysis/AbstractDomainUsageAnalysis.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/analysis/AbstractDomainUsageAnalysis.java
index 965a38bc5..9df1ebe27 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/analysis/AbstractDomainUsageAnalysis.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/analysis/AbstractDomainUsageAnalysis.java
@@ -83,10 +83,8 @@ import org.eclipse.qvtd.pivot.qvtimperative.BottomPattern;
 import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
 import org.eclipse.qvtd.pivot.qvtimperative.GuardPattern;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.OppositePropertyAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.util.AbstractExtendingQVTimperativeVisitor;
 import org.eclipse.qvtd.pivot.qvtimperative.utilities.QVTimperativeUtil;
@@ -108,22 +106,6 @@ public abstract class AbstractDomainUsageAnalysis extends AbstractExtendingQVTim
 		return element2usage.get(element);
 	}
 
-	protected @NonNull DomainUsage doNavigationAssignment(@NonNull Property property, @NonNull NavigationAssignment object) {
-		DomainUsage slotUsage = visit(object.getSlotExpression());
-		DomainUsage valueUsage = visit(object.getValue());
-		DomainUsage knownSourceUsage = getRootAnalysis().property2containingClassUsage.get(property);
-		if (knownSourceUsage != null) {
-			DomainUsage knownTargetUsage = getRootAnalysis().getUsage(property);
-			assert knownTargetUsage != null;
-			intersection(knownSourceUsage, slotUsage);
-			intersection(knownTargetUsage, valueUsage);
-			return knownSourceUsage; //intersection(knownTargetUsage, valueUsage);
-		}
-		else {
-			return slotUsage; //intersection(slotUsage, valueUsage);
-		}
-	}
-
 	protected @NonNull DomainUsage doNavigationCallExp(@NonNull Property property, @NonNull NavigationCallExp object) {
 		DomainUsage actualSourceUsage = visit(object.getOwnedSource());
 		DomainUsage knownPropertyUsage = visit(property);
@@ -144,6 +126,22 @@ public abstract class AbstractDomainUsageAnalysis extends AbstractExtendingQVTim
 		return usage;
 	}
 
+	protected @NonNull DomainUsage doSetStatement(@NonNull Property property, @NonNull SetStatement object) {
+		DomainUsage slotUsage = visit(object.getSlotExpression());
+		DomainUsage valueUsage = visit(object.getValue());
+		DomainUsage knownSourceUsage = getRootAnalysis().property2containingClassUsage.get(property);
+		if (knownSourceUsage != null) {
+			DomainUsage knownTargetUsage = getRootAnalysis().getUsage(property);
+			assert knownTargetUsage != null;
+			intersection(knownSourceUsage, slotUsage);
+			intersection(knownTargetUsage, valueUsage);
+			return knownSourceUsage; //intersection(knownTargetUsage, valueUsage);
+		}
+		else {
+			return slotUsage; //intersection(slotUsage, valueUsage);
+		}
+	}
+
 	protected @NonNull DomainUsage getAllInstancesUsage(@NonNull OperationCallExp object, @NonNull DomainUsage sourceUsage) {
 		return sourceUsage;
 	}
@@ -572,15 +570,6 @@ public abstract class AbstractDomainUsageAnalysis extends AbstractExtendingQVTim
 	}
 
 	@Override
-	public @NonNull DomainUsage visitNavigationAssignment(@NonNull NavigationAssignment object) {
-		Property property = QVTimperativeUtil.getTargetProperty(object);
-		//		if ("middleRoot.name := hsvRoot.name".equals(object.toString())) {
-		//			property = object.getTargetProperty();
-		//		}
-		return doNavigationAssignment(property, object);
-	}
-
-	@Override
 	public @NonNull DomainUsage visitNullLiteralExp(@NonNull NullLiteralExp object) {
 		return getRootAnalysis().createVariableUsage(getRootAnalysis().getAnyMask());
 	}
@@ -710,11 +699,6 @@ public abstract class AbstractDomainUsageAnalysis extends AbstractExtendingQVTim
 	}
 
 	@Override
-	public @NonNull DomainUsage visitOppositePropertyAssignment(@NonNull OppositePropertyAssignment object) {
-		return visitNavigationAssignment(object);
-	}
-
-	@Override
 	public @NonNull DomainUsage visitOppositePropertyCallExp(@NonNull OppositePropertyCallExp object) {
 		Property property = ClassUtil.nonNullState(object.getReferredProperty());
 		Property oppositeProperty = ClassUtil.nonNullState(property.getOpposite());
@@ -753,11 +737,6 @@ public abstract class AbstractDomainUsageAnalysis extends AbstractExtendingQVTim
 	}
 
 	@Override
-	public @NonNull DomainUsage visitPropertyAssignment(@NonNull PropertyAssignment object) {
-		return visitNavigationAssignment(object);
-	}
-
-	@Override
 	public @NonNull DomainUsage visitPropertyCallExp(@NonNull PropertyCallExp object) {
 		Property property = ClassUtil.nonNullState(object.getReferredProperty());
 		return doNavigationCallExp(property, object);
@@ -782,6 +761,15 @@ public abstract class AbstractDomainUsageAnalysis extends AbstractExtendingQVTim
 	}
 
 	@Override
+	public @NonNull DomainUsage visitSetStatement(@NonNull SetStatement object) {
+		Property property = QVTimperativeUtil.getTargetProperty(object);
+		//		if ("middleRoot.name := hsvRoot.name".equals(object.toString())) {
+		//			property = object.getTargetProperty();
+		//		}
+		return doSetStatement(property, object);
+	}
+
+	@Override
 	public @NonNull DomainUsage visitShadowExp(@NonNull ShadowExp object) {
 		DomainUsage usage = visit(object.getType());
 		for (@SuppressWarnings("null")@NonNull ShadowPart part : object.getOwnedParts()) {
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/analysis/RootDomainUsageAnalysis.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/analysis/RootDomainUsageAnalysis.java
index af20aba41..b8506c013 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/analysis/RootDomainUsageAnalysis.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/analysis/RootDomainUsageAnalysis.java
@@ -55,7 +55,7 @@ import org.eclipse.qvtd.pivot.qvtbase.utilities.QVTbaseUtil;
 import org.eclipse.qvtd.pivot.qvtimperative.Area;
 import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.util.QVTimperativeVisitor;
 import org.eclipse.qvtd.pivot.qvtimperative.utilities.QVTimperativeUtil;
 
@@ -372,19 +372,19 @@ public class RootDomainUsageAnalysis extends AbstractDomainUsageAnalysis impleme
 		return analysis;
 	}
 
-	protected void analyzePropertyAssignments(@NonNull Transformation transformation) {
+	protected void analyzeSetStatements(@NonNull Transformation transformation) {
 		for (TreeIterator<EObject> tit = transformation.eAllContents(); tit.hasNext(); ) {
 			EObject eObject = tit.next();
-			if (eObject instanceof PropertyAssignment) {
-				PropertyAssignment propertyAssignment = (PropertyAssignment)eObject;
+			if (eObject instanceof SetStatement) {
+				SetStatement setStatement = (SetStatement)eObject;
 				//				if ("s.name := sn".equals(eObject.toString())) {
 				//					eObject.toString();
 				//				}
-				OCLExpression slotExpression = propertyAssignment.getSlotExpression();
+				OCLExpression slotExpression = setStatement.getSlotExpression();
 				assert slotExpression != null;
 				DomainUsage domainUsage = getUsage(slotExpression);
 				if (!domainUsage.isOutput() && !domainUsage.isMiddle()) {
-					Property targetProperty = ClassUtil.nonNullState(propertyAssignment.getTargetProperty());
+					Property targetProperty = QVTimperativeUtil.getTargetProperty(setStatement);
 					//					System.out.println("Dirty " + targetProperty + " for " + eObject);
 					dirtyProperties.add(targetProperty);
 					EObject eProperty = targetProperty.getESObject();
@@ -493,7 +493,7 @@ public class RootDomainUsageAnalysis extends AbstractDomainUsageAnalysis impleme
 			setUsage(ownedContext, getAnyUsage());
 		}
 		visit(transformation);
-		analyzePropertyAssignments(transformation);
+		analyzeSetStatements(transformation);
 		return element2usage;
 	}
 
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/attributes/SetStatementAttribution.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/attributes/SetStatementAttribution.java
new file mode 100644
index 000000000..93e4dca10
--- /dev/null
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/attributes/SetStatementAttribution.java
@@ -0,0 +1,36 @@
+/*******************************************************************************
+ * Copyright (c) 2013, 2014 Willink Transformations and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     E.D.Willink - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.qvtd.pivot.qvtimperative.attributes;
+
+import org.eclipse.emf.ecore.EObject;
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.ocl.pivot.PivotPackage;
+import org.eclipse.ocl.pivot.internal.scoping.EmptyAttribution;
+import org.eclipse.ocl.pivot.internal.scoping.EnvironmentView;
+import org.eclipse.ocl.pivot.internal.scoping.ScopeView;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
+
+public class SetStatementAttribution extends EmptyAttribution
+{
+	public static final SetStatementAttribution INSTANCE = new SetStatementAttribution();
+
+	@Override
+	public ScopeView computeLookup(@NonNull EObject target, @NonNull EnvironmentView environmentView, @NonNull ScopeView scopeView) {
+		SetStatement asSetStatement = (SetStatement)target;
+		if (environmentView.getRequiredType() == PivotPackage.Literals.PROPERTY) {		// FIXME should be detecting ancestor
+			environmentView.addElementsOfScope(asSetStatement.getSlotExpression().getType(), scopeView);
+			return null;
+		}
+		else {
+			return super.computeLookup(target, environmentView, scopeView);
+		}
+	}
+}
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/BasicQVTiExecutor.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/BasicQVTiExecutor.java
index c0cad2d4a..9ed5e3766 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/BasicQVTiExecutor.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/BasicQVTiExecutor.java
@@ -63,8 +63,8 @@ import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.Statement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.utilities.QVTimperativeUtil;
@@ -436,17 +436,6 @@ public class BasicQVTiExecutor extends AbstractExecutor implements QVTiExecutor
 	}
 
 	@Override
-	public void internalExecuteNavigationAssignment(@NonNull NavigationAssignment navigationAssignment, @NonNull Object slotObject, @Nullable Object ecoreValue, @Nullable Object childKey) {
-		Property targetProperty = QVTimperativeUtil.getTargetProperty(navigationAssignment);
-		targetProperty.initValue(slotObject, ecoreValue);
-		QVTiModelManager modelManager = getModelManager();
-		Integer cacheIndex = modelManager.getTransformationAnalysis().getCacheIndex(navigationAssignment);
-		if (cacheIndex != null) {
-			modelManager.setUnnavigableOpposite(cacheIndex, slotObject, ecoreValue);
-		}
-	}
-
-	@Override
 	public @Nullable Object internalExecuteOperationCallExp(@NonNull OperationCallExp operationCallExp,
 			@Nullable Object @NonNull [] boxedSourceAndArgumentValues) {
 		Operation referredOperation = operationCallExp.getReferredOperation();
@@ -478,6 +467,17 @@ public class BasicQVTiExecutor extends AbstractExecutor implements QVTiExecutor
 	}
 
 	@Override
+	public void internalExecuteSetStatement(@NonNull SetStatement setStatement, @NonNull Object slotObject, @Nullable Object ecoreValue, @Nullable Object childKey) {
+		Property targetProperty = QVTimperativeUtil.getTargetProperty(setStatement);
+		targetProperty.initValue(slotObject, ecoreValue);
+		QVTiModelManager modelManager = getModelManager();
+		Integer cacheIndex = modelManager.getTransformationAnalysis().getCacheIndex(setStatement);
+		if (cacheIndex != null) {
+			modelManager.setUnnavigableOpposite(cacheIndex, slotObject, ecoreValue);
+		}
+	}
+
+	@Override
 	public @Nullable Object internalExecuteTransformation(@NonNull Transformation transformation, @NonNull EvaluationVisitor undecoratedVisitor) {
 		Rule rule = NameUtil.getNameable(transformation.getRule(), QVTimperativeUtil.ROOT_MAPPING_NAME);
 		if (rule == null) {
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiAbstractTracingEvaluationVisitor.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiAbstractTracingEvaluationVisitor.java
index 91ab89153..ebaa45d0e 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiAbstractTracingEvaluationVisitor.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiAbstractTracingEvaluationVisitor.java
@@ -32,17 +32,18 @@ import org.eclipse.ocl.pivot.values.InvalidValueException;
 import org.eclipse.qvtd.pivot.qvtbase.Predicate;
 import org.eclipse.qvtd.pivot.qvtbase.Transformation;
 import org.eclipse.qvtd.pivot.qvtimperative.Assignment;
-import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
 import org.eclipse.qvtd.pivot.qvtimperative.GuardPattern;
+import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
 import org.eclipse.qvtd.pivot.qvtimperative.ImperativeModel;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingStatement;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.Statement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.VariablePredicate;
+import org.eclipse.qvtd.pivot.qvtimperative.utilities.QVTimperativeUtil;
 
 /**
  * The Class QVTiTracingEvaluationVisitor is a decorator visitor that prints
@@ -296,20 +297,20 @@ public abstract class QVTiAbstractTracingEvaluationVisitor extends QVTiEvaluatio
 	 * @see org.eclipse.qvtd.pivot.qvtimperative.evaluation.QVTiEvaluationVisitorDecorator#visitPropertyAssignment(org.eclipse.qvtd.pivot.qvtcorebase.PropertyAssignment)
 	 */
 	@Override
-	public @Nullable Object visitPropertyAssignment(@NonNull PropertyAssignment propertyAssignment) {
+	public @Nullable Object visitSetStatement(@NonNull SetStatement setStatement) {
 
 		try {
-			Object value = safeVisit(propertyAssignment.getValue());
+			Object value = safeVisit(setStatement.getValue());
 			// Unbox to asign to ecore type
 			value = delegate.getEnvironmentFactory().getIdResolver().unboxedValueOf(value);
-			logger.info(getIndent() + "VisitPropertyAssignment " + propertyAssignment.getSlotExpression()
-			+ "." + propertyAssignment.getTargetProperty().getName() + " = " + prettyPrint(value));
+			logger.info(getIndent() + "VisitSetStatement " + setStatement.getSlotExpression()
+			+ "." + QVTimperativeUtil.getTargetProperty(setStatement).getName() + " = " + prettyPrint(value));
 		} catch (InvalidValueException ex) {
-			logger.info(getIndent() + "VisitPropertyAssignment " + propertyAssignment.getSlotExpression()
-			+ "." + propertyAssignment.getTargetProperty().getName() + " = InvalidValueException" );
+			logger.info(getIndent() + "VisitSetStatement " + setStatement.getSlotExpression()
+			+ "." + QVTimperativeUtil.getTargetProperty(setStatement).getName() + " = InvalidValueException" );
 		}
 		//indentLevel++;
-		Object result = delegate.visitPropertyAssignment(propertyAssignment);
+		Object result = delegate.visitSetStatement(setStatement);
 		//indentLevel--;
 		return result;
 	}
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitor.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitor.java
index db27dd9aa..5cad01098 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitor.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitor.java
@@ -39,6 +39,7 @@ import org.eclipse.qvtd.pivot.qvtbase.Transformation;
 import org.eclipse.qvtd.pivot.qvtbase.TypedModel;
 import org.eclipse.qvtd.pivot.qvtimperative.Assignment;
 import org.eclipse.qvtd.pivot.qvtimperative.BottomPattern;
+import org.eclipse.qvtd.pivot.qvtimperative.BottomStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionVariable;
@@ -51,10 +52,8 @@ import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingStatement;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.OppositePropertyAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.Statement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.VariablePredicate;
@@ -114,6 +113,11 @@ public class QVTiEvaluationVisitor extends BasicEvaluationVisitor implements IQV
 	}
 
 	@Override
+	public @Nullable Object visitBottomStatement(@NonNull BottomStatement object) {
+		return visitStatement(object);	// MappingStatement is abstract
+	}
+
+	@Override
 	public @Nullable Object visitConnectionAssignment(@NonNull ConnectionAssignment connectionAssignment) {
 		ConnectionVariable targetVariable = connectionAssignment.getTargetVariable() ;
 		if (targetVariable != null) {
@@ -266,47 +270,6 @@ public class QVTiEvaluationVisitor extends BasicEvaluationVisitor implements IQV
 		return visitStatement(object);	// MappingStatement is abstract
 	}
 
-	@Override
-	public @Nullable Object visitNavigationAssignment(@NonNull NavigationAssignment navigationAssignment) {
-		Object slotObject = navigationAssignment.getSlotExpression().accept(undecoratedVisitor);
-		if (slotObject instanceof EObject) {
-			Integer childKey = null;
-			try {
-				Object boxedValue = navigationAssignment.getValue().accept(undecoratedVisitor);
-				Property targetProperty = QVTimperativeUtil.getTargetProperty(navigationAssignment);
-				Class<?> instanceClass = PivotUtil.getEcoreInstanceClass(targetProperty);
-				Object ecoreValue = idResolver.ecoreValueOf(instanceClass, boxedValue);
-				Property oppositeProperty = targetProperty.getOpposite();
-				if (oppositeProperty != null) {
-					Type type = oppositeProperty.getType();
-					if (type instanceof CollectionType) {
-						boolean isOrdered = ((CollectionType)type).isOrdered();
-						if (isOrdered) {
-
-						}
-					}
-				}
-				executor.internalExecuteNavigationAssignment(navigationAssignment, slotObject, ecoreValue, childKey);
-				return null;
-			}
-			catch (InvocationFailedException e) {
-				executor.internalExecuteNavigationAssignment(navigationAssignment, slotObject, e, childKey);
-				//				throw e;
-			}
-			//		} else if (slotObject == null){
-			//			throw new InvalidValueException("Null source for '" + navigationAssignment.toString() + "'");
-		} else {
-			throw new IllegalArgumentException("Unsupported " + navigationAssignment.eClass().getName()
-				+ " specification. The assignment slot expression '" + navigationAssignment.toString() + "'evaluates to non-ecore value: " + NameUtil.debugFullName(slotObject));
-		}
-		return true;
-	}
-
-	@Override
-	public @Nullable Object visitOppositePropertyAssignment(@NonNull OppositePropertyAssignment navigationAssignment) {
-		return visitNavigationAssignment(navigationAssignment);
-	}
-
 	/*	@Override
 	public Object visitOppositePropertyCallExp(@NonNull OppositePropertyCallExp oppositePropertyCallExp) {
 		QVTiModelManager modelManager = (QVTiModelManager) context.getModelManager();
@@ -349,11 +312,6 @@ public class QVTiEvaluationVisitor extends BasicEvaluationVisitor implements IQV
 	}
 
 	@Override
-	public @Nullable Object visitPropertyAssignment(@NonNull PropertyAssignment navigationAssignment) {
-		return visitNavigationAssignment(navigationAssignment);
-	}
-
-	@Override
 	public @Nullable Object visitRealizedVariable(@NonNull RealizedVariable realizedVariable) {
 		return executor.internalExecuteRealizedVariable(realizedVariable, undecoratedVisitor);
 	}
@@ -364,6 +322,42 @@ public class QVTiEvaluationVisitor extends BasicEvaluationVisitor implements IQV
 	}
 
 	@Override
+	public @Nullable Object visitSetStatement(@NonNull SetStatement setStatement) {
+		Object slotObject = setStatement.getSlotExpression().accept(undecoratedVisitor);
+		if (slotObject instanceof EObject) {
+			Integer childKey = null;
+			try {
+				Object boxedValue = setStatement.getValue().accept(undecoratedVisitor);
+				Property targetProperty = QVTimperativeUtil.getTargetProperty(setStatement);
+				Class<?> instanceClass = PivotUtil.getEcoreInstanceClass(targetProperty);
+				Object ecoreValue = idResolver.ecoreValueOf(instanceClass, boxedValue);
+				Property oppositeProperty = targetProperty.getOpposite();
+				if (oppositeProperty != null) {
+					Type type = oppositeProperty.getType();
+					if (type instanceof CollectionType) {
+						boolean isOrdered = ((CollectionType)type).isOrdered();
+						if (isOrdered) {
+
+						}
+					}
+				}
+				executor.internalExecuteSetStatement(setStatement, slotObject, ecoreValue, childKey);
+				return null;
+			}
+			catch (InvocationFailedException e) {
+				executor.internalExecuteSetStatement(setStatement, slotObject, e, childKey);		// FIXME This leads to an AssertionError in PropertyImpl.initValue
+				//				throw e;
+			}
+			//		} else if (slotObject == null){
+			//			throw new InvalidValueException("Null source for '" + navigationAssignment.toString() + "'");
+		} else {
+			throw new IllegalArgumentException("Unsupported " + setStatement.eClass().getName()
+				+ " specification. The assignment slot expression '" + setStatement.toString() + "'evaluates to non-ecore value: " + NameUtil.debugFullName(slotObject));
+		}
+		return true;
+	}
+
+	@Override
 	public @Nullable Object visitStatement(@NonNull Statement object) {
 		return visitNamedElement(object);	// Statement is abstract
 	}
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitorDecorator.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitorDecorator.java
index fc52421ed..927d1710f 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitorDecorator.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiEvaluationVisitorDecorator.java
@@ -30,15 +30,15 @@ import org.eclipse.qvtd.pivot.qvtbase.Transformation;
 import org.eclipse.qvtd.pivot.qvtbase.TypedModel;
 import org.eclipse.qvtd.pivot.qvtimperative.Assignment;
 import org.eclipse.qvtd.pivot.qvtimperative.BottomPattern;
-import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
-import org.eclipse.qvtd.pivot.qvtimperative.ImperativePattern;
 import org.eclipse.qvtd.pivot.qvtimperative.GuardPattern;
+import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
 import org.eclipse.qvtd.pivot.qvtimperative.ImperativeModel;
+import org.eclipse.qvtd.pivot.qvtimperative.ImperativePattern;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 
 /**
@@ -294,24 +294,24 @@ implements IQVTiEvaluationVisitor {
 	 * Delegates to my decorated visitor.
 	 */
 	@Override
-	public @Nullable Object visitPropertyAssignment(@NonNull PropertyAssignment propertyAssignment) {
-		return delegate.visitPropertyAssignment(propertyAssignment);
+	public @Nullable Object visitRealizedVariable(@NonNull RealizedVariable realizedVariable) {
+		return delegate.visitRealizedVariable(realizedVariable);
 	}
 
 	/**
 	 * Delegates to my decorated visitor.
 	 */
 	@Override
-	public @Nullable Object visitRealizedVariable(@NonNull RealizedVariable realizedVariable) {
-		return delegate.visitRealizedVariable(realizedVariable);
+	public @Nullable Object visitRule(@NonNull Rule rule) {
+		return delegate.visitRule(rule);
 	}
 
 	/**
 	 * Delegates to my decorated visitor.
 	 */
 	@Override
-	public @Nullable Object visitRule(@NonNull Rule rule) {
-		return delegate.visitRule(rule);
+	public @Nullable Object visitSetStatement(@NonNull SetStatement setStatement) {
+		return delegate.visitSetStatement(setStatement);
 	}
 
 	/**
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiExecutor.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiExecutor.java
index a5a7116bf..6a4750095 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiExecutor.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiExecutor.java
@@ -20,8 +20,8 @@ import org.eclipse.ocl.pivot.internal.evaluation.ExecutorInternal;
 import org.eclipse.qvtd.pivot.qvtbase.Transformation;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 
 public interface QVTiExecutor extends ExecutorInternal
 {
@@ -34,8 +34,8 @@ public interface QVTiExecutor extends ExecutorInternal
 	@NonNull QVTiModelManager getModelManager();
 	@Nullable Object internalExecuteMapping(@NonNull Mapping mapping, @NonNull EvaluationVisitor undecoratedVisitor);
 	@Nullable Object internalExecuteMappingCall(@NonNull MappingCall mappingCall, @NonNull Object @NonNull [] boundValues, @NonNull EvaluationVisitor undecoratedVisitor);
-	void internalExecuteNavigationAssignment(@NonNull NavigationAssignment navigationAssignment, @NonNull Object slotObject, @Nullable Object ecoreValue, @Nullable Object childKey);
 	@Nullable Object internalExecuteRealizedVariable(@NonNull RealizedVariable realizedVariable, @NonNull EvaluationVisitor undecoratedVisitor);
+	void internalExecuteSetStatement(@NonNull SetStatement setStatement, @NonNull Object slotObject, @Nullable Object ecoreValue, @Nullable Object childKey);
 	@Nullable Object internalExecuteTransformation(@NonNull Transformation transformation, @NonNull EvaluationVisitor undecoratedVisitor);
 	void loadModel(@NonNull String inName, @NonNull URI inURI, @Nullable String contentType);
 	void replace(@NonNull TypedElement referredVariable, @Nullable Object value, boolean checkType);
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiIncrementalExecutor.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiIncrementalExecutor.java
index 106704501..198dd8856 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiIncrementalExecutor.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiIncrementalExecutor.java
@@ -32,8 +32,8 @@ import org.eclipse.qvtd.pivot.qvtbase.Transformation;
 import org.eclipse.qvtd.pivot.qvtbase.graphs.GraphStringBuilder;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.utilities.QVTimperativeUtil;
 import org.eclipse.qvtd.runtime.evaluation.AbstractComputation;
 import org.eclipse.qvtd.runtime.evaluation.AbstractInvocation;
@@ -266,20 +266,36 @@ public class QVTiIncrementalExecutor extends BasicQVTiExecutor
 	}
 
 	@Override
-	public void internalExecuteNavigationAssignment(@NonNull NavigationAssignment navigationAssignment, @NonNull Object sourceObject, @Nullable Object ecoreValue, @Nullable Object childKey) {
-		super.internalExecuteNavigationAssignment(navigationAssignment, sourceObject, ecoreValue, childKey);
+	public @Nullable Object internalExecuteRealizedVariable(@NonNull RealizedVariable realizedVariable, @NonNull EvaluationVisitor undecoratedVisitor) {
+		Object element = super.internalExecuteRealizedVariable(realizedVariable, undecoratedVisitor);
+		if ((element != null) && (mode == Mode.INCREMENTAL)) {
+			Invocation.Incremental currentInvocation2 = currentInvocation;
+			assert currentInvocation2 != null;
+			objectManager.created(currentInvocation2, element);
+			/*			DomainUsage domainUsage = getEvaluationEnvironment().getUsageFor(realizedVariable);
+			ClassStatus classStatus = statusManager.getClassStatus(domainUsage, realizedVariable.getType(), (EObject)element);
+			MappingStatus mappingStatus = findMappingStatus();
+			assert mappingStatus != null;
+			mappingStatus.getOutputs().add(classStatus); */
+		}
+		return element;
+	}
+
+	@Override
+	public void internalExecuteSetStatement(@NonNull SetStatement setStatement, @NonNull Object sourceObject, @Nullable Object ecoreValue, @Nullable Object childKey) {
+		super.internalExecuteSetStatement(setStatement, sourceObject, ecoreValue, childKey);
 		if (mode == Mode.LAZY) {
-			Mapping asMapping = QVTimperativeUtil.getContainingMapping(navigationAssignment);
+			Mapping asMapping = QVTimperativeUtil.getContainingMapping(setStatement);
 			assert asMapping != null;
-			if (transformationAnalysis.isHazardousWrite(asMapping, navigationAssignment)) {
-				Property targetProperty = QVTimperativeUtil.getTargetProperty(navigationAssignment);
+			if (transformationAnalysis.isHazardousWrite(asMapping, setStatement)) {
+				Property targetProperty = QVTimperativeUtil.getTargetProperty(setStatement);
 				assert targetProperty != null;
 				EStructuralFeature eFeature = (EStructuralFeature)targetProperty.getESObject();
 				objectManager.assigned(sourceObject, eFeature, ecoreValue, childKey);
 			}
 		}
 		else {
-			Property targetProperty = QVTimperativeUtil.getTargetProperty(navigationAssignment);
+			Property targetProperty = QVTimperativeUtil.getTargetProperty(setStatement);
 			assert targetProperty != null;
 			EStructuralFeature eFeature = (EStructuralFeature)targetProperty.getESObject();
 			Invocation.Incremental currentInvocation2 = currentInvocation;
@@ -287,20 +303,4 @@ public class QVTiIncrementalExecutor extends BasicQVTiExecutor
 			objectManager.assigned(currentInvocation2, sourceObject, eFeature, ecoreValue, childKey);
 		}
 	}
-
-	@Override
-	public @Nullable Object internalExecuteRealizedVariable(@NonNull RealizedVariable realizedVariable, @NonNull EvaluationVisitor undecoratedVisitor) {
-		Object element = super.internalExecuteRealizedVariable(realizedVariable, undecoratedVisitor);
-		if ((element != null) && (mode == Mode.INCREMENTAL)) {
-			Invocation.Incremental currentInvocation2 = currentInvocation;
-			assert currentInvocation2 != null;
-			objectManager.created(currentInvocation2, element);
-			/*			DomainUsage domainUsage = getEvaluationEnvironment().getUsageFor(realizedVariable);
-			ClassStatus classStatus = statusManager.getClassStatus(domainUsage, realizedVariable.getType(), (EObject)element);
-			MappingStatus mappingStatus = findMappingStatus();
-			assert mappingStatus != null;
-			mappingStatus.getOutputs().add(classStatus); */
-		}
-		return element;
-	}
 }
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiTransformationAnalysis.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiTransformationAnalysis.java
index 3aa5326f7..61de06241 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiTransformationAnalysis.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiTransformationAnalysis.java
@@ -32,6 +32,7 @@ import org.eclipse.ocl.pivot.PrimitiveType;
 import org.eclipse.ocl.pivot.Property;
 import org.eclipse.ocl.pivot.PropertyCallExp;
 import org.eclipse.ocl.pivot.Type;
+import org.eclipse.ocl.pivot.VariableExp;
 import org.eclipse.ocl.pivot.ids.IdManager;
 import org.eclipse.ocl.pivot.ids.OperationId;
 import org.eclipse.ocl.pivot.ids.TypeId;
@@ -50,8 +51,7 @@ import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.analysis.QVTimperativeDomainUsageAnalysis;
 import org.eclipse.qvtd.pivot.qvtimperative.utilities.QVTimperativeUtil;
 
@@ -63,7 +63,7 @@ import org.eclipse.qvtd.pivot.qvtimperative.utilities.QVTimperativeUtil;
  * Salient characteristics are:
  * <br>
  * - the source types of allInstances() calls
- * - cache indexes of MiddlePropertyAssignment/MiddlePropertyCallExp
+ * - cache indexes of MiddleSetStatement/MiddlePropertyCallExp
  */
 public class QVTiTransformationAnalysis
 {
@@ -77,59 +77,59 @@ public class QVTiTransformationAnalysis
 	/**
 	 *  Set of all types for which allInstances() is invoked.
 	 */
-	private final @NonNull Set<org.eclipse.ocl.pivot.@NonNull Class> allInstancesClasses = new HashSet<org.eclipse.ocl.pivot.@NonNull Class>();
+	private final @NonNull Set<org.eclipse.ocl.pivot.@NonNull Class> allInstancesClasses = new HashSet<>();
 
 	/**
 	 *  Map from navigable property to sequential index in any TypedModel.
 	 */
-	private final @NonNull Map<@NonNull Property, @NonNull Integer> property2cacheIndex = new HashMap<@NonNull Property, @NonNull Integer>();
+	private final @NonNull Map<@NonNull Property, @NonNull Integer> property2cacheIndex = new HashMap<>();
 
 	/**
 	 *  Map from navigable property to sequential index in a checkable TypedModel.
 	 */
-	private final @NonNull Map<Property, Integer> sourceProperty2cacheIndex = new HashMap<Property, Integer>();
+	private final @NonNull Map<@NonNull Property, @NonNull Integer> sourceProperty2cacheIndex = new HashMap<>();
 
 	/**
 	 * Map from propertyAssignment to the cache index of an un-navigable lookup cache to be updated by the assignment.
 	 */
-	private final @NonNull Map<NavigationAssignment, Integer> navigationAssignment2cacheIndex = new HashMap<NavigationAssignment, Integer>();
+	private final @NonNull Map<@NonNull SetStatement, @NonNull Integer> setStatement2cacheIndex = new HashMap<>();
 
 	/**
 	 * Map from oppositePropertyCallExp to the cache index identifying the relevant un-navigable lookup cache.
 	 */
-	private final @NonNull Map<OppositePropertyCallExp, Integer> oppositePropertyCallExp2cacheIndex = new HashMap<OppositePropertyCallExp, Integer>();
+	private final @NonNull Map<@NonNull OppositePropertyCallExp, @NonNull Integer> oppositePropertyCallExp2cacheIndex = new HashMap<>();
 
 	/**
 	 * Map from operation to the properties that it may access.
 	 */
-	private final @NonNull Map<Operation, Set<NavigationCallExp>> operation2property = new HashMap<Operation, Set<NavigationCallExp>>();
+	private final @NonNull Map<@NonNull Operation, @NonNull Set<@NonNull NavigationCallExp>> operation2property = new HashMap<>();
 
 	/**
 	 * Map from mapping to the properties that it may access.
 	 */
-	private final @NonNull Map<Mapping, Set<NavigationCallExp>> mapping2property = new HashMap<Mapping, Set<NavigationCallExp>>();
+	private final @NonNull Map<@NonNull Mapping, @NonNull Set<@NonNull NavigationCallExp>> mapping2property = new HashMap<>();
 
 	/**
 	 * Map from mapping to the properties that it may assign.
 	 */
-	private final @NonNull Map<Mapping, Set<PropertyAssignment>> mapping2propertyAssignments = new HashMap<Mapping, Set<PropertyAssignment>>();
+	private final @NonNull Map<@NonNull Mapping, @NonNull Set<@NonNull SetStatement>> mapping2propertyAssignments = new HashMap<>();
 
 	/**
 	 * Mappings that have an isPolled input.
 	 */
-	private final @NonNull Set<Mapping> hazardousMappings = new HashSet<Mapping>();
+	private final @NonNull Set<@NonNull Mapping> hazardousMappings = new HashSet<>();
 
-	private final @NonNull Set<Property> hazardousProperties = new HashSet<Property>();
+	private final @NonNull Set<@NonNull Property> hazardousProperties = new HashSet<>();
 
 	/**
-	 * The PropertyAssignments to each Property.
+	 * The SetStatements to each Property.
 	 */
-	private final @NonNull Map<Property, Set<PropertyAssignment>> property2propertyAssignments = new HashMap<Property, Set<PropertyAssignment>>();
+	private final @NonNull Map<@NonNull Property, @NonNull Set<@NonNull SetStatement>> property2propertyAssignments = new HashMap<>();
 
 	/**
 	 * Map of all oclContainer() accesses.
 	 */
-	private final @NonNull Map<Type, List<Type>> parentClass2childClasses = new HashMap<Type, List<Type>>();
+	private final @NonNull Map<@NonNull Type, @NonNull List<@NonNull Type>> parentClass2childClasses = new HashMap<>();
 
 	public QVTiTransformationAnalysis(@NonNull EnvironmentFactoryInternal environmentFactory) {
 		this.environmentFactory = environmentFactory;
@@ -164,61 +164,65 @@ public class QVTiTransformationAnalysis
 		return cacheIndex;
 	}
 
-	private @NonNull Set<NavigationCallExp> analyzeMappingPropertyAccesses(@NonNull Mapping mapping) {
-		Set<NavigationCallExp> accessedProperties = mapping2property.get(mapping);
+	private @NonNull Set<@NonNull NavigationCallExp> analyzeMappingPropertyAccesses(@NonNull Mapping mapping) {
+		Set<@NonNull NavigationCallExp> accessedProperties = mapping2property.get(mapping);
 		if (accessedProperties != null) {
 			return accessedProperties;
 		}
-		accessedProperties = new HashSet<NavigationCallExp>();
+		accessedProperties = new HashSet<>();
 		mapping2property.put(mapping, accessedProperties);
 		analyzeTree(accessedProperties, mapping.eAllContents());
 		return accessedProperties;
 	}
 
-	private @NonNull Set<PropertyAssignment> analyzeMappingPropertyAssignments(@NonNull Mapping mapping) {
-		Set<PropertyAssignment> assignedProperties = mapping2propertyAssignments.get(mapping);
+	private @NonNull Set<@NonNull SetStatement> analyzeMappingSetStatements(@NonNull Mapping mapping) {
+		Set<@NonNull SetStatement> assignedProperties = mapping2propertyAssignments.get(mapping);
 		if (assignedProperties == null) {
-			assignedProperties = new HashSet<PropertyAssignment>();
+			assignedProperties = new HashSet<>();
 			mapping2propertyAssignments.put(mapping, assignedProperties);
 		}
 		for (TreeIterator<EObject> treeIterator = mapping.eAllContents(); treeIterator.hasNext(); ) {
 			EObject eObject = treeIterator.next();
-			if (eObject instanceof PropertyAssignment) {
-				assignedProperties.add((PropertyAssignment) eObject);
+			if (eObject instanceof SetStatement) {
+				assignedProperties.add((SetStatement) eObject);
 			}
 		}
 		return assignedProperties;
 	}
 
-	private @NonNull Set<NavigationCallExp> analyzeOperation(@NonNull Operation operation) {
-		Set<NavigationCallExp> operationProperties = operation2property.get(operation);
+	private @NonNull Set<@NonNull NavigationCallExp> analyzeOperation(@NonNull Operation operation) {
+		Set<@NonNull NavigationCallExp> operationProperties = operation2property.get(operation);
 		if (operationProperties != null) {
 			return operationProperties;
 		}
-		operationProperties = new HashSet<NavigationCallExp>();
+		operationProperties = new HashSet<>();
 		operation2property.put(operation, operationProperties);
 		analyzeTree(operationProperties, operation.eAllContents());
 		return operationProperties;
 	}
 
 	private void analyzeProperties() {
-		Set<Mapping> hazardousMappings = getHazardousMappings();
-		for (Map.Entry<Mapping, Set<NavigationCallExp>> entry : getMapping2Property().entrySet()) {
+		Set<@NonNull Mapping> hazardousMappings = getHazardousMappings();
+		for (Map.Entry<@NonNull Mapping, @NonNull Set<@NonNull NavigationCallExp>> entry : getMapping2Property().entrySet()) {
 			Mapping mapping = entry.getKey();
 			if (hazardousMappings.contains(mapping)) {
-				for (@SuppressWarnings("null")@NonNull NavigationCallExp hazardousPropertyCallExp : entry.getValue()) {
+				for (@NonNull NavigationCallExp hazardousPropertyCallExp : entry.getValue()) {
 					Property hazardousProperty = PivotUtil.getReferredProperty(hazardousPropertyCallExp);
 					hazardousProperties.add(hazardousProperty);
-					hazardousProperties.add(hazardousProperty.getOpposite());
+					Property oppositeProperty = hazardousProperty.getOpposite();
+					if (oppositeProperty != null) {
+						hazardousProperties.add(oppositeProperty);
+					}
 				}
 			}
 		}
-		for (Set<PropertyAssignment> propertyAssignments : mapping2propertyAssignments.values()) {
-			for (PropertyAssignment propertyAssignment : propertyAssignments) {
+		for (@NonNull Set<@NonNull SetStatement> propertyAssignments : mapping2propertyAssignments.values()) {
+			for (@NonNull SetStatement propertyAssignment : propertyAssignments) {
 				Property property = propertyAssignment.getTargetProperty();
-				Set<PropertyAssignment> assignments = property2propertyAssignments.get(property);
+				assert property != null;
+				Set<@NonNull SetStatement> assignments = property2propertyAssignments.get(property);
 				if (assignments == null) {
-					assignments = new HashSet<PropertyAssignment>();
+					assignments = new HashSet<>();
 					property2propertyAssignments.put(property, assignments);
 				}
 				assignments.add(propertyAssignment);
@@ -242,10 +246,12 @@ public class QVTiTransformationAnalysis
 					LibraryFeature implementation = referredProperty.getImplementation();
 					if (implementation instanceof OclElementOclContainerProperty) {
 						Type childType = asPropertyCallExp.getOwnedSource().getType();
+						assert childType != null;
 						Type parentType = asPropertyCallExp.getType();
-						List<Type> childClasses = parentClass2childClasses .get(parentType);
+						assert parentType != null;
+						List<@NonNull Type> childClasses = parentClass2childClasses .get(parentType);
 						if (childClasses == null) {
-							childClasses = new ArrayList<Type>();
+							childClasses = new ArrayList<>();
 							parentClass2childClasses.put(parentType, childClasses);
 						}
 						if (!childClasses.contains(childType)) {
@@ -276,7 +282,7 @@ public class QVTiTransformationAnalysis
 		//
 		//	First pass
 		//  - identify all allInstances() source types
-		//  - identify all PropertyAssignments
+		//  - identify all SetStatements
 		//  - identify all assigned PropertyCallExp and allocate a cacheIndex
 		//
 		Type oclElementType = environmentFactory.getStandardLibrary().getOclElementType();
@@ -284,13 +290,13 @@ public class QVTiTransformationAnalysis
 		OperationId allInstancesOperationId = oclElementType.getTypeId().getOperationId(0, "allInstances", IdManager.getParametersId());
 		OperationId objectsOfKindOperationId = modelType.getTypeId().getOperationId(1, "objectsOfKind", IdManager.getParametersId(TypeId.T_1));
 		OperationId objectsOfTypeOperationId = modelType.getTypeId().getOperationId(1, "objectsOfType", IdManager.getParametersId(TypeId.T_1));
-		List<PropertyAssignment> propertyAssignments = new ArrayList<PropertyAssignment>();
+		List<@NonNull SetStatement> propertyAssignments = new ArrayList<>();
 		for (TreeIterator<EObject> tit = transformation.eAllContents(); tit.hasNext(); ) {
 			EObject eObject = tit.next();
 			if (eObject instanceof Mapping) {
 				Mapping mapping = (Mapping)eObject;
 				analyzeMappingPropertyAccesses(mapping);
-				analyzeMappingPropertyAssignments(mapping);
+				analyzeMappingSetStatements(mapping);
 				if (mapping.getCheckedProperties().size() > 0) {
 					hazardousMappings.add(mapping);
 				}
@@ -310,6 +316,7 @@ public class QVTiTransformationAnalysis
 				MappingCallBinding mappingCallBinding = (MappingCallBinding)eObject;
 				if (mappingCallBinding.isIsPolled()) {
 					Mapping mapping = mappingCallBinding.getMappingCall().getReferredMapping();
+					assert mapping != null;
 					hazardousMappings.add(mapping);
 				}
 			}
@@ -321,8 +328,8 @@ public class QVTiTransformationAnalysis
 					oppositePropertyCallExp2cacheIndex.put(oppositePropertyCallExp, cacheIndex);
 				}
 			}
-			else if (eObject instanceof PropertyAssignment) {
-				propertyAssignments.add((PropertyAssignment)eObject);
+			else if (eObject instanceof SetStatement) {
+				propertyAssignments.add((SetStatement)eObject);
 			}
 			else if (eObject instanceof OperationCallExp) {
 				OperationCallExp operationCallExp = (OperationCallExp)eObject;
@@ -353,14 +360,14 @@ public class QVTiTransformationAnalysis
 		}
 		//
 		//	Second pass
-		//  - install cacheIndex allocated to MiddlePropertyCallExp in each MiddlePropertyAssignment
+		//  - install cacheIndex allocated to MiddlePropertyCallExp in each MiddleSetStatement
 		//
-		for (PropertyAssignment propertyAssignment : propertyAssignments) {
+		for (@NonNull SetStatement propertyAssignment : propertyAssignments) {
 			Property navigableProperty = propertyAssignment.getTargetProperty();
 			if (navigableProperty != null) {
 				Integer cacheIndex = property2cacheIndex.get(navigableProperty);
 				if (cacheIndex != null) { 		// No need to set cacheIndex if it is never accessed by an OppositePropertyCallExp
-					navigationAssignment2cacheIndex.put(propertyAssignment, cacheIndex);
+					setStatement2cacheIndex.put(propertyAssignment, cacheIndex);
 				}
 			}
 		}
@@ -376,8 +383,8 @@ public class QVTiTransformationAnalysis
 		return oppositePropertyCallExp2cacheIndex.get(oppositePropertyCallExp);
 	}
 
-	public @Nullable Integer getCacheIndex(@NonNull NavigationAssignment navigationAssignment) {
-		return navigationAssignment2cacheIndex.get(navigationAssignment);
+	public @Nullable Integer getCacheIndex(@NonNull SetStatement setStatement) {
+		return setStatement2cacheIndex.get(setStatement);
 	}
 
 	public int getCacheIndexes() {
@@ -392,7 +399,7 @@ public class QVTiTransformationAnalysis
 		return domainAnalysis;
 	}
 
-	public @NonNull Set<Mapping> getHazardousMappings() {
+	public @NonNull Set<@NonNull Mapping> getHazardousMappings() {
 		return hazardousMappings;
 	}
 
@@ -400,14 +407,14 @@ public class QVTiTransformationAnalysis
 	 * Return a Map from each instanceClasses to the subset of instanceClasses that are transitive superClasses of the particular instanceClass.
 	 */
 	public @NonNull Map<org.eclipse.ocl.pivot.@NonNull Class, @Nullable List<org.eclipse.ocl.pivot.@NonNull Class>> getInstancesClassAnalysis(@NonNull Iterable<org.eclipse.ocl.pivot.@NonNull Class> instanceClasses) {
-		Map<org.eclipse.ocl.pivot.@NonNull Class, @Nullable List<org.eclipse.ocl.pivot.@NonNull Class>> instancesClassAnalysis = new HashMap<org.eclipse.ocl.pivot.@NonNull Class, @Nullable List<org.eclipse.ocl.pivot.@NonNull Class>>();
+		Map<org.eclipse.ocl.pivot.@NonNull Class, @Nullable List<org.eclipse.ocl.pivot.@NonNull Class>> instancesClassAnalysis = new HashMap<>();
 		MetamodelManagerInternal metamodelManager = environmentFactory.getMetamodelManager();
 		for (org.eclipse.ocl.pivot.@NonNull Class instanceClass : instanceClasses) {
 			CompleteClass completeInstanceClass = metamodelManager.getCompleteClass(instanceClass);
 			instancesClassAnalysis.put(completeInstanceClass.getPrimaryClass(), null);
 		}
 		for (org.eclipse.ocl.pivot.@NonNull Class instanceClass : instancesClassAnalysis.keySet()) {
-			List<org.eclipse.ocl.pivot.Class> superInstanceClasses = new ArrayList<org.eclipse.ocl.pivot.Class>();
+			List<org.eclipse.ocl.pivot.Class> superInstanceClasses = new ArrayList<>();
 			superInstanceClasses.add(instanceClass);
 			CompleteClass completeClass = metamodelManager.getCompleteClass(instanceClass);
 			for (@NonNull CompleteClass superCompleteClass : completeClass.getProperSuperCompleteClasses()) {
@@ -421,11 +428,11 @@ public class QVTiTransformationAnalysis
 		return instancesClassAnalysis;
 	}
 
-	public @NonNull Map<Mapping, Set<NavigationCallExp>> getMapping2Property() {
+	public @NonNull Map<@NonNull Mapping, @NonNull Set<@NonNull NavigationCallExp>> getMapping2Property() {
 		return mapping2property;
 	}
 
-	public @NonNull Map<Mapping, Set<PropertyAssignment>> getMapping2PropertyAssignments() {
+	public @NonNull Map<Mapping, @NonNull Set<@NonNull SetStatement>> getMapping2SetStatements() {
 		return mapping2propertyAssignments;
 	}
 
@@ -450,7 +457,7 @@ public class QVTiTransformationAnalysis
 		return opposite2cacheIndex;
 	} */
 
-	public @NonNull Map<Property, Integer> getSourceCaches() {
+	public @NonNull Map<@NonNull Property, @NonNull Integer> getSourceCaches() {
 		return sourceProperty2cacheIndex;
 	}
 
@@ -465,11 +472,11 @@ public class QVTiTransformationAnalysis
 
 	public boolean hasHazardousWrite(@NonNull MappingCall mappingCall) {
 		Mapping mapping = mappingCall.getReferredMapping();
-		Set<PropertyAssignment> propertyAssignments = mapping2propertyAssignments.get(mapping);
+		Set<@NonNull SetStatement> propertyAssignments = mapping2propertyAssignments.get(mapping);
 		if (propertyAssignments == null) {
 			return false;
 		}
-		for (PropertyAssignment propertyAssignment : propertyAssignments) {
+		for (@NonNull SetStatement propertyAssignment : propertyAssignments) {
 			Property assignedProperty = propertyAssignment.getTargetProperty();
 			if (hazardousProperties.contains(assignedProperty)) {
 				return true;
@@ -482,11 +489,11 @@ public class QVTiTransformationAnalysis
 	}
 
 	public boolean isAssigned(@NonNull Property targetProperty, @NonNull DomainUsage domainUsage) {
-		Set<PropertyAssignment> propertyAssignments = property2propertyAssignments.get(targetProperty);
+		Set<@NonNull SetStatement> propertyAssignments = property2propertyAssignments.get(targetProperty);
 		if (propertyAssignments == null) {
 			return false;
 		}
-		for (PropertyAssignment propertyAssignment : propertyAssignments) {
+		for (@NonNull SetStatement propertyAssignment : propertyAssignments) {
 			OCLExpression slotExpression = propertyAssignment.getSlotExpression();
 			DomainUsage slotUsage = domainAnalysis.basicGetUsage(slotExpression);
 			if (domainUsage == slotUsage) {
@@ -507,11 +514,11 @@ public class QVTiTransformationAnalysis
 		Type parentType = targetProperty.getOwningClass();
 		Type childType = targetProperty.getType();
 		assert childType != null;
-		for (Map.Entry<Type, List<Type>> entry : parentClass2childClasses.entrySet()) {
+		for (Map.Entry<@NonNull Type, @NonNull List<@NonNull Type>> entry : parentClass2childClasses.entrySet()) {
 			Type entryType = entry.getKey();
 			assert entryType != null;
 			if (parentType.conformsTo(standardLibrary, entryType)) {
-				for (Type type : entry.getValue()) {
+				for (@NonNull Type type : entry.getValue()) {
 					if (type.conformsTo(standardLibrary, childType)) {
 						return true;
 					}
@@ -552,9 +559,9 @@ public class QVTiTransformationAnalysis
 		return false;
 	}
 
-	public boolean isHazardousWrite(@NonNull Mapping asMapping, @NonNull NavigationAssignment asNavigationAssignment) {
-		Property asProperty = QVTimperativeUtil.getTargetProperty(asNavigationAssignment);
-		OCLExpression asSource = asNavigationAssignment.getSlotExpression();
+	public boolean isHazardousWrite(@NonNull Mapping asMapping, @NonNull SetStatement asSetStatement) {
+		Property asProperty = QVTimperativeUtil.getTargetProperty(asSetStatement);
+		VariableExp asSource = asSetStatement.getSlotExpression();
 		DomainUsage domainUsage = getDomainUsageAnalysis().basicGetUsage(asSource);
 		if (domainUsage != null) {
 			TypedModel typedModel = domainUsage.getTypedModel(asSource);
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiTuneUpVisitor.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiTuneUpVisitor.java
index 6ca1cc67b..4d4a67055 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiTuneUpVisitor.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/evaluation/QVTiTuneUpVisitor.java
@@ -47,7 +47,6 @@ import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingStatement;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.QVTimperativeFactory;
 import org.eclipse.qvtd.pivot.qvtimperative.Statement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
@@ -108,22 +107,6 @@ public class QVTiTuneUpVisitor extends AbstractExtendingQVTimperativeVisitor<Boo
 			else if (assignment instanceof VariableAssignment) {
 				variableAssignments.add(assignment);
 			}
-			else if (assignment instanceof PropertyAssignment) {
-				PropertyAssignment propertyAssignment = (PropertyAssignment)assignment;
-				OCLExpression slot = propertyAssignment.getSlotExpression();
-				if ((slot != null) && (slot.accept(this) != Boolean.TRUE)) {
-					propertyAssignment.setSlotExpression(null);			// Avoid a child stealing detection
-					VariableExp variableExp = rewritePropertyAssignmentTerm(object, variableAssignments, slot);
-					propertyAssignment.setSlotExpression(variableExp);
-				}
-				OCLExpression value = propertyAssignment.getValue();
-				if ((value != null) && (value.accept(this) != Boolean.TRUE)) {
-					propertyAssignment.setValue(null);			// Avoid a child stealing detection
-					VariableExp variableExp = rewritePropertyAssignmentTerm(object, variableAssignments, value);
-					propertyAssignment.setValue(variableExp);
-				}
-				propertyAssignments.add(propertyAssignment);
-			}
 			else {
 				assignment.accept(this);
 			}
@@ -273,6 +256,11 @@ public class QVTiTuneUpVisitor extends AbstractExtendingQVTimperativeVisitor<Boo
 	}
 
 	@Override
+	public Boolean visitStatement(@NonNull Statement object) {
+		return Boolean.TRUE;
+	}
+
+	@Override
 	public @Nullable Boolean visitTransformation(@NonNull Transformation object) {
 		for (Rule rule : object.getRule()) {
 			rule.accept(this);
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/scoping/QVTimperativePivotScoping.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/scoping/QVTimperativePivotScoping.java
index 06d8d21c9..99353a9fa 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/scoping/QVTimperativePivotScoping.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/scoping/QVTimperativePivotScoping.java
@@ -19,6 +19,7 @@ import org.eclipse.qvtd.pivot.qvtimperative.attributes.CoreDomainAttribution;
 import org.eclipse.qvtd.pivot.qvtimperative.attributes.MappingAttribution;
 import org.eclipse.qvtd.pivot.qvtimperative.attributes.MappingCallBindingAttribution;
 import org.eclipse.qvtd.pivot.qvtimperative.attributes.MappingLoopAttribution;
+import org.eclipse.qvtd.pivot.qvtimperative.attributes.SetStatementAttribution;
 import org.eclipse.qvtd.pivot.qvtimperative.attributes.QVTimperativeBottomPatternAttribution;
 import org.eclipse.qvtd.pivot.qvtimperative.attributes.QVTimperativeGuardPatternAttribution;
 
@@ -32,5 +33,6 @@ public class QVTimperativePivotScoping
 		registry.put(QVTimperativePackage.Literals.MAPPING, MappingAttribution.INSTANCE);
 		registry.put(QVTimperativePackage.Literals.MAPPING_CALL_BINDING, MappingCallBindingAttribution.INSTANCE);
 		registry.put(QVTimperativePackage.Literals.MAPPING_LOOP, MappingLoopAttribution.INSTANCE);
+		registry.put(QVTimperativePackage.Literals.SET_STATEMENT, SetStatementAttribution.INSTANCE);
 	}
 }
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/AssignmentComparator.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/AssignmentComparator.java
index a14d33486..5f777de17 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/AssignmentComparator.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/AssignmentComparator.java
@@ -21,14 +21,12 @@ import java.util.Set;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
-import org.eclipse.ocl.pivot.Property;
 import org.eclipse.ocl.pivot.Variable;
 import org.eclipse.ocl.pivot.VariableDeclaration;
 import org.eclipse.ocl.pivot.VariableExp;
 import org.eclipse.ocl.pivot.utilities.ClassUtil;
 import org.eclipse.ocl.pivot.utilities.TreeIterable;
 import org.eclipse.qvtd.pivot.qvtimperative.Assignment;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 
 /**
@@ -45,29 +43,8 @@ public class AssignmentComparator implements Comparator<@NonNull Assignment>
 
 	@Override
 	public int compare(@NonNull Assignment o1, @NonNull Assignment o2) {
-		if (o1 instanceof PropertyAssignment) {
-			if (o2 instanceof PropertyAssignment) {
-				Property p1 = ((PropertyAssignment)o1).getTargetProperty();
-				Property p2 = ((PropertyAssignment)o2).getTargetProperty();
-				String n1 = p1.getName();
-				String n2 = p2.getName();
-				int diff = ClassUtil.safeCompareTo(n1, n2);
-				if (diff != 0) {
-					return diff;
-				}
-				n1 = p1.toString();
-				n2 = p2.toString();
-				return ClassUtil.safeCompareTo(n1, n2);
-			}
-			else {
-				return 1;
-			}
-		}
-		else if (o1 instanceof VariableAssignment) {
-			if (o2 instanceof PropertyAssignment) {
-				return -1;
-			}
-			else if (o2 instanceof VariableAssignment) {
+		if (o1 instanceof VariableAssignment) {
+			if (o2 instanceof VariableAssignment) {
 				Map<@NonNull Variable, @NonNull Set<@NonNull Variable>> variable2referencedVariables2 = variable2referencedVariables;
 				if (variable2referencedVariables2 == null) {
 					variable2referencedVariables2 = variable2referencedVariables = computeReferencedVariableClosure();
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeHelper.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeHelper.java
index 22e28964e..ca5041ea0 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeHelper.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeHelper.java
@@ -20,11 +20,9 @@ import org.eclipse.ocl.pivot.utilities.EnvironmentFactory;
 import org.eclipse.qvtd.pivot.qvtbase.utilities.QVTbaseHelper;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionVariable;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.OppositePropertyAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.QVTimperativeFactory;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 
 /**
@@ -52,23 +50,6 @@ public class QVTimperativeHelper extends QVTbaseHelper
 		return asVariable;
 	}
 
-	public @NonNull NavigationAssignment createNavigationAssignment(@NonNull OCLExpression asSlotExpression, @NonNull Property asProperty, @NonNull OCLExpression asValueExpression) {
-		NavigationAssignment asNavigationAssignment;
-		if (asProperty.isIsImplicit()) {
-			OppositePropertyAssignment asPropertyAssignment = QVTimperativeFactory.eINSTANCE.createOppositePropertyAssignment();
-			asPropertyAssignment.setTargetProperty(asProperty.getOpposite());
-			asNavigationAssignment = asPropertyAssignment;
-		}
-		else {
-			PropertyAssignment asPropertyAssignment = QVTimperativeFactory.eINSTANCE.createPropertyAssignment();
-			asPropertyAssignment.setTargetProperty(asProperty);
-			asNavigationAssignment = asPropertyAssignment;
-		}
-		asNavigationAssignment.setSlotExpression(asSlotExpression);
-		asNavigationAssignment.setValue(asValueExpression);
-		return asNavigationAssignment;
-	}
-
 	public @NonNull RealizedVariable createRealizedVariable(@NonNull String name, @NonNull Type type) {
 		RealizedVariable realizedVariable = QVTimperativeFactory.eINSTANCE.createRealizedVariable();
 		realizedVariable.setName(name);
@@ -77,6 +58,10 @@ public class QVTimperativeHelper extends QVTbaseHelper
 		return realizedVariable;
 	}
 
+	public @NonNull SetStatement createSetStatement(@NonNull Variable asVariable, @NonNull Property asProperty, @NonNull OCLExpression asValueExpression) {
+		return QVTimperativeUtil.createSetStatement(asVariable, asProperty, asValueExpression);
+	}
+
 	public @NonNull VariableAssignment createVariableAssignment(@NonNull Variable asVariable, @NonNull OCLExpression asValueExpression) {
 		VariableAssignment asVariableAssignment = QVTimperativeFactory.eINSTANCE.createVariableAssignment();
 		asVariableAssignment.setTargetVariable(asVariable);
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativePrettyPrintVisitor.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativePrettyPrintVisitor.java
index e9baec9b8..75ede3489 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativePrettyPrintVisitor.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativePrettyPrintVisitor.java
@@ -22,6 +22,7 @@ import org.eclipse.qvtd.pivot.qvtbase.utilities.QVTbasePrettyPrintVisitor;
 import org.eclipse.qvtd.pivot.qvtimperative.Area;
 import org.eclipse.qvtd.pivot.qvtimperative.Assignment;
 import org.eclipse.qvtd.pivot.qvtimperative.BottomPattern;
+import org.eclipse.qvtd.pivot.qvtimperative.BottomStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionVariable;
@@ -34,10 +35,8 @@ import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingStatement;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.OppositePropertyAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.Statement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.VariablePredicate;
@@ -89,6 +88,11 @@ public class QVTimperativePrettyPrintVisitor extends QVTbasePrettyPrintVisitor i
 	}
 
 	@Override
+	public Object visitBottomStatement(@NonNull BottomStatement object) {
+		return visitStatement(object);
+	}
+
+	@Override
 	public Object visitConnectionAssignment(@NonNull ConnectionAssignment asConnectionAssignment) {
 		context.appendName(asConnectionAssignment.getTargetVariable());
 		context.append(" += ");
@@ -215,33 +219,12 @@ public class QVTimperativePrettyPrintVisitor extends QVTbasePrettyPrintVisitor i
 	}
 
 	@Override
-	public Object visitNavigationAssignment(@NonNull NavigationAssignment asNavigationAssignment) {
-		safeVisit(asNavigationAssignment.getSlotExpression());
-		context.append(".");
-		context.appendName(QVTimperativeUtil.getTargetProperty(asNavigationAssignment));
-		context.append(" := ");
-		safeVisit(asNavigationAssignment.getValue());
-		context.append(";\n");
-		return null;
-	}
-
-	@Override
-	public Object visitOppositePropertyAssignment(@NonNull OppositePropertyAssignment asNavigationAssignment) {
-		return visitNavigationAssignment(asNavigationAssignment);
-	}
-
-	@Override
 	public Object visitPredicate(@NonNull Predicate pPredicate) {
 		safeVisit(pPredicate.getConditionExpression());
 		return null;
 	}
 
 	@Override
-	public Object visitPropertyAssignment(@NonNull PropertyAssignment asNavigationAssignment) {
-		return visitNavigationAssignment(asNavigationAssignment);
-	}
-
-	@Override
 	public Object visitRealizedVariable(@NonNull RealizedVariable pRealizedVariable) {
 		context.append("realize ");
 		visitVariable(pRealizedVariable);
@@ -249,6 +232,18 @@ public class QVTimperativePrettyPrintVisitor extends QVTbasePrettyPrintVisitor i
 	}
 
 	@Override
+	public Object visitSetStatement(@NonNull SetStatement asSetStatement) {
+		context.append("set ");
+		safeVisit(asSetStatement.getSlotExpression());
+		context.append(".");
+		context.appendName(QVTimperativeUtil.getTargetProperty(asSetStatement));
+		context.append(" := ");
+		safeVisit(asSetStatement.getValue());
+		context.append(";\n");
+		return null;
+	}
+
+	@Override
 	public Object visitStatement(@NonNull Statement object) {
 		return visiting(object);
 	}
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeToStringVisitor.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeToStringVisitor.java
index 9f5313401..a9e7abd71 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeToStringVisitor.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeToStringVisitor.java
@@ -19,6 +19,7 @@ import org.eclipse.ocl.pivot.utilities.ToStringVisitor;
 import org.eclipse.qvtd.pivot.qvtbase.utilities.QVTbaseToStringVisitor;
 import org.eclipse.qvtd.pivot.qvtimperative.Assignment;
 import org.eclipse.qvtd.pivot.qvtimperative.BottomPattern;
+import org.eclipse.qvtd.pivot.qvtimperative.BottomStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionVariable;
@@ -31,11 +32,9 @@ import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingStatement;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.OppositePropertyAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.QVTimperativePackage;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.Statement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.VariablePredicate;
@@ -88,6 +87,11 @@ public class QVTimperativeToStringVisitor extends QVTbaseToStringVisitor impleme
 	}
 
 	@Override
+	public String visitBottomStatement(@NonNull BottomStatement object) {
+		return visitStatement(object);
+	}
+
+	@Override
 	public @Nullable String visitConnectionAssignment(@NonNull ConnectionAssignment connectionAssignment) {
 		appendName(connectionAssignment.getTargetVariable());
 		append(" += ");
@@ -182,33 +186,24 @@ public class QVTimperativeToStringVisitor extends QVTbaseToStringVisitor impleme
 
 	@Override
 	public @Nullable String visitMappingStatement(@NonNull MappingStatement object) {
-		return null;
+		return visitStatement(object);
 	}
 
 	@Override
-	public String visitNavigationAssignment(@NonNull NavigationAssignment asNavigationAssignment) {
-		safeVisit(asNavigationAssignment.getSlotExpression());
-		append(".");
-		appendName(QVTimperativeUtil.getTargetProperty(asNavigationAssignment));
-		append(" := ");
-		safeVisit(asNavigationAssignment.getValue());
+	public String visitRealizedVariable(@NonNull RealizedVariable variable) {
+		//		append("realized ");
+		visitVariable(variable);
 		return null;
 	}
 
 	@Override
-	public String visitOppositePropertyAssignment(@NonNull OppositePropertyAssignment asNavigationAssignment) {
-		return visitNavigationAssignment(asNavigationAssignment);
-	}
-
-	@Override
-	public String visitPropertyAssignment(@NonNull PropertyAssignment asNavigationAssignment) {
-		return visitNavigationAssignment(asNavigationAssignment);
-	}
-
-	@Override
-	public String visitRealizedVariable(@NonNull RealizedVariable variable) {
-		//		append("realized ");
-		visitVariable(variable);
+	public String visitSetStatement(@NonNull SetStatement asSetStatement) {
+		append("set ");
+		safeVisit(asSetStatement.getSlotExpression());
+		append(".");
+		appendName(QVTimperativeUtil.getTargetProperty(asSetStatement));
+		append(" := ");
+		safeVisit(asSetStatement.getValue());
 		return null;
 	}
 
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeUtil.java b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeUtil.java
index 3fea951d7..e0b11f954 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeUtil.java
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/src/org/eclipse/qvtd/pivot/qvtimperative/utilities/QVTimperativeUtil.java
@@ -49,18 +49,16 @@ import org.eclipse.qvtd.pivot.qvtbase.utilities.QVTbaseEnvironmentFactory.Create
 import org.eclipse.qvtd.pivot.qvtbase.utilities.QVTbaseUtil;
 import org.eclipse.qvtd.pivot.qvtimperative.Area;
 import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
-import org.eclipse.qvtd.pivot.qvtimperative.ImperativePattern;
 import org.eclipse.qvtd.pivot.qvtimperative.ImperativeModel;
+import org.eclipse.qvtd.pivot.qvtimperative.ImperativePattern;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingStatement;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.OppositePropertyAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.QVTimperativeFactory;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariablePredicate;
 import org.eclipse.qvtd.pivot.qvtimperative.evaluation.QVTiEnvironmentFactory;
 
@@ -205,14 +203,6 @@ public class QVTimperativeUtil extends QVTbaseUtil
 		return property;
 	}
 
-	public static @NonNull PropertyAssignment createPropertyAssignment(@NonNull OCLExpression slotExpression, @NonNull Property targetProperty, @NonNull OCLExpression value) {
-		PropertyAssignment propertyAssignment = QVTimperativeFactory.eINSTANCE.createPropertyAssignment();
-		propertyAssignment.setSlotExpression(slotExpression);
-		propertyAssignment.setTargetProperty(targetProperty);
-		propertyAssignment.setValue(value);
-		return propertyAssignment;
-	}
-
 	/*	public static @NonNull PropertyCallExp createPropertyCallExp(@NonNull OCLExpression source, @NonNull Property property) {
 		PropertyCallExp propertyCallExp = PivotFactory.eINSTANCE.createPropertyCallExp();
 		propertyCallExp.setOwnedSource(source);
@@ -229,6 +219,21 @@ public class QVTimperativeUtil extends QVTbaseUtil
 		return realizedVariable;
 	}
 
+	public static @NonNull SetStatement createSetStatement(@NonNull Variable asVariable, @NonNull Property asProperty, @NonNull OCLExpression asValueExpression) {
+		SetStatement asSetAssignment = QVTimperativeFactory.eINSTANCE.createSetStatement();
+		if (asProperty.isIsImplicit()) {
+			asSetAssignment.setTargetProperty(asProperty.getOpposite());
+			asSetAssignment.setIsOpposite(true);
+		}
+		else {
+			asSetAssignment.setTargetProperty(asProperty);
+			asSetAssignment.setIsOpposite(false);
+		}
+		asSetAssignment.setSlotExpression(createVariableExp(asVariable));
+		asSetAssignment.setValue(asValueExpression);
+		return asSetAssignment;
+	}
+
 	public static @NonNull Transformation createTransformation(@NonNull String name) {
 		Transformation transformation = QVTbaseFactory.eINSTANCE.createTransformation();
 		transformation.setName(name);
@@ -295,15 +300,9 @@ public class QVTimperativeUtil extends QVTbaseUtil
 		return (ImperativeDomain)getDomain((Rule)rule, typedModel);
 	}
 
-	public static @NonNull Property getTargetProperty(@NonNull NavigationAssignment asNavigationAssignment) {
-		if (asNavigationAssignment instanceof PropertyAssignment) {
-			return ClassUtil.nonNullState(((PropertyAssignment)asNavigationAssignment).getTargetProperty());
-		}
-		else if (asNavigationAssignment instanceof OppositePropertyAssignment) {
-			Property referredProperty = ClassUtil.nonNullState(((OppositePropertyAssignment)asNavigationAssignment).getTargetProperty());
-			return ClassUtil.nonNullState(referredProperty.getOpposite());
-		}
-		throw new UnsupportedOperationException("Unsupported " + asNavigationAssignment.eClass().getName());
+	public static @NonNull Property getTargetProperty(@NonNull SetStatement asSetStatement) {
+		Property referredProperty = ClassUtil.nonNullState(asSetStatement.getTargetProperty());
+		return asSetStatement.isIsOpposite() ? ClassUtil.nonNullState(referredProperty.getOpposite()) : referredProperty;
 	}
 
 	public static @Nullable TypedModel getTypedModel(@Nullable Area area) {
diff --git a/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/icons/PropertyAssignment.gif b/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/icons/SetStatement.gif
index 085b712fb..085b712fb 100644
--- a/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/icons/PropertyAssignment.gif
+++ b/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/icons/SetStatement.gif
diff --git a/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/src/org/eclipse/qvtd/xtext/qvtimperative/ui/labeling/QVTimperativeLabelProvider.java b/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/src/org/eclipse/qvtd/xtext/qvtimperative/ui/labeling/QVTimperativeLabelProvider.java
index 906763cd7..c359486af 100644
--- a/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/src/org/eclipse/qvtd/xtext/qvtimperative/ui/labeling/QVTimperativeLabelProvider.java
+++ b/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/src/org/eclipse/qvtd/xtext/qvtimperative/ui/labeling/QVTimperativeLabelProvider.java
@@ -28,8 +28,8 @@ import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.xtext.qvtbase.ui.labeling.QVTbaseLabelProvider;
 import org.eclipse.qvtd.xtext.qvtimperativecs.DomainCS;
@@ -91,8 +91,8 @@ public class QVTimperativeLabelProvider extends QVTbaseLabelProvider
 		return "MappingCallBinding.gif";
 	}
 
-	protected String image(PropertyAssignment ele) {
-		return QVTIMPERATIVE_UI_ICONS + "PropertyAssignment.gif";
+	protected String image(SetStatement ele) {
+		return QVTIMPERATIVE_UI_ICONS + "SetStatement.gif";
 	}
 
 	protected String image(RealizedVariable ele) {
@@ -147,7 +147,7 @@ public class QVTimperativeLabelProvider extends QVTbaseLabelProvider
 		return "«predicate»";
 	}
 
-	protected String text(PropertyAssignment ele) {
+	protected String text(SetStatement ele) {
 		assert ele != null;
 		Namespace namespace = PivotUtil.getNamespace(ele.eContainer());
 		if (namespace == null) {
diff --git a/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/src/org/eclipse/qvtd/xtext/qvtimperative/ui/outline/QVTimperativeOutlineTreeProvider.java b/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/src/org/eclipse/qvtd/xtext/qvtimperative/ui/outline/QVTimperativeOutlineTreeProvider.java
index 8ae0a14e9..d4a71f168 100644
--- a/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/src/org/eclipse/qvtd/xtext/qvtimperative/ui/outline/QVTimperativeOutlineTreeProvider.java
+++ b/plugins/org.eclipse.qvtd.xtext.qvtimperative.ui/src/org/eclipse/qvtd/xtext/qvtimperative/ui/outline/QVTimperativeOutlineTreeProvider.java
@@ -20,7 +20,7 @@ import org.eclipse.qvtd.pivot.qvtimperative.BottomPattern;
 import org.eclipse.qvtd.pivot.qvtimperative.GuardPattern;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingStatement;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.xtext.qvtbase.ui.outline.QVTbaseOutlineTreeProvider;
 import org.eclipse.qvtd.xtext.qvtimperativecs.DirectionCS;
@@ -77,7 +77,7 @@ public class QVTimperativeOutlineTreeProvider extends QVTbaseOutlineTreeProvider
 		}
 	}
 
-	protected void _createChildren(IOutlineNode parentNode, PropertyAssignment ele) {
+	protected void _createChildren(IOutlineNode parentNode, SetStatement ele) {
 		createNode(parentNode, ele.getValue());
 	}
 
diff --git a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/as2cs/QVTimperativeDeclarationVisitor.java b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/as2cs/QVTimperativeDeclarationVisitor.java
index 96b2d7e44..94317c5ea 100644
--- a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/as2cs/QVTimperativeDeclarationVisitor.java
+++ b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/as2cs/QVTimperativeDeclarationVisitor.java
@@ -58,7 +58,6 @@ import org.eclipse.ocl.xtext.basecs.RootPackageCS;
 import org.eclipse.ocl.xtext.basecs.TypedRefCS;
 import org.eclipse.ocl.xtext.essentialoclcs.EssentialOCLCSPackage;
 import org.eclipse.ocl.xtext.essentialoclcs.ExpCS;
-import org.eclipse.ocl.xtext.essentialoclcs.NameExpCS;
 import org.eclipse.ocl.xtext.essentialoclcs.VariableCS;
 import org.eclipse.qvtd.pivot.qvtbase.BaseModel;
 import org.eclipse.qvtd.pivot.qvtbase.Domain;
@@ -73,22 +72,21 @@ import org.eclipse.qvtd.pivot.qvtbase.utilities.QVTbaseUtil;
 import org.eclipse.qvtd.pivot.qvtimperative.Area;
 import org.eclipse.qvtd.pivot.qvtimperative.Assignment;
 import org.eclipse.qvtd.pivot.qvtimperative.BottomPattern;
+import org.eclipse.qvtd.pivot.qvtimperative.BottomStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.ConnectionVariable;
-import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
-import org.eclipse.qvtd.pivot.qvtimperative.ImperativePattern;
 import org.eclipse.qvtd.pivot.qvtimperative.GuardPattern;
+import org.eclipse.qvtd.pivot.qvtimperative.ImperativeDomain;
 import org.eclipse.qvtd.pivot.qvtimperative.ImperativeModel;
+import org.eclipse.qvtd.pivot.qvtimperative.ImperativePattern;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingStatement;
-import org.eclipse.qvtd.pivot.qvtimperative.NavigationAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.OppositePropertyAssignment;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.Statement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.VariablePredicate;
@@ -114,6 +112,7 @@ import org.eclipse.qvtd.xtext.qvtimperativecs.PredicateOrAssignmentCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.QVTimperativeCSPackage;
 import org.eclipse.qvtd.xtext.qvtimperativecs.QueryCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.RealizedVariableCS;
+import org.eclipse.qvtd.xtext.qvtimperativecs.SetStatementCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.StatementCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.TopLevelCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.TransformationCS;
@@ -396,6 +395,11 @@ public class QVTimperativeDeclarationVisitor extends QVTbaseDeclarationVisitor i
 	}
 
 	@Override
+	public ElementCS visitBottomStatement(@NonNull BottomStatement object) {
+		return visitStatement(object);
+	}
+
+	@Override
 	public ElementCS visitConnectionAssignment(@NonNull ConnectionAssignment asConnectionAssignment) {
 		PredicateOrAssignmentCS csAssignment = context.refreshElement(PredicateOrAssignmentCS.class, QVTimperativeCSPackage.Literals.PREDICATE_OR_ASSIGNMENT_CS, asConnectionAssignment);
 		csAssignment.setPivot(asConnectionAssignment);
@@ -590,22 +594,6 @@ public class QVTimperativeDeclarationVisitor extends QVTbaseDeclarationVisitor i
 	}
 
 	@Override
-	public ElementCS visitNavigationAssignment(@NonNull NavigationAssignment asNavigationAssignment) {
-		PredicateOrAssignmentCS csAssignment = context.refreshElement(PredicateOrAssignmentCS.class, QVTimperativeCSPackage.Literals.PREDICATE_OR_ASSIGNMENT_CS, asNavigationAssignment);
-		ExpCS csSlotExp = createExpCS(asNavigationAssignment.getSlotExpression());
-		NameExpCS csPropName = createNameExpCS(QVTimperativeUtil.getTargetProperty(asNavigationAssignment));
-		csAssignment.setOwnedTarget(createInfixExpCS(csSlotExp, ".", csPropName));
-		csAssignment.setOwnedInitExpression(createExpCS(asNavigationAssignment.getValue()));
-		csAssignment.setIsDefault(asNavigationAssignment.isIsDefault());
-		return csAssignment;
-	}
-
-	@Override
-	public ElementCS visitOppositePropertyAssignment(@NonNull OppositePropertyAssignment asNavigationAssignment) {
-		return visitNavigationAssignment(asNavigationAssignment);
-	}
-
-	@Override
 	public ElementCS visitPackage(org.eclipse.ocl.pivot.@NonNull Package asPackage) {
 		//		List<org.eclipse.ocl.pivot.@NonNull Class> asClasses = ClassUtil.nullFree(asPackage.getOwnedClasses());
 		//		List<org.eclipse.ocl.pivot.@NonNull Package> asPackages = ClassUtil.nullFree(asPackage.getOwnedPackages());
@@ -660,18 +648,6 @@ public class QVTimperativeDeclarationVisitor extends QVTbaseDeclarationVisitor i
 	}
 
 	@Override
-	public ElementCS visitPropertyAssignment(@NonNull PropertyAssignment asPropertyAssignment) {
-		PredicateOrAssignmentCS csAssignment = context.refreshElement(PredicateOrAssignmentCS.class, QVTimperativeCSPackage.Literals.PREDICATE_OR_ASSIGNMENT_CS, asPropertyAssignment);
-		csAssignment.setPivot(asPropertyAssignment);
-		ExpCS csSlotExp = createExpCS(asPropertyAssignment.getSlotExpression());
-		NameExpCS csPropName = createNameExpCS(asPropertyAssignment.getTargetProperty());
-		csAssignment.setOwnedTarget(createInfixExpCS(csSlotExp, ".", csPropName));
-		csAssignment.setOwnedInitExpression(createExpCS(asPropertyAssignment.getValue()));
-		csAssignment.setIsDefault(asPropertyAssignment.isIsDefault());
-		return csAssignment;
-	}
-
-	@Override
 	public ElementCS visitRealizedVariable(@NonNull RealizedVariable asRealizedVariable) {
 		RealizedVariableCS csRealizedVariable = context.refreshNamedElement(RealizedVariableCS.class, QVTimperativeCSPackage.Literals.REALIZED_VARIABLE_CS, asRealizedVariable);
 		csRealizedVariable.setPivot(asRealizedVariable);
@@ -686,6 +662,15 @@ public class QVTimperativeDeclarationVisitor extends QVTbaseDeclarationVisitor i
 	}
 
 	@Override
+	public ElementCS visitSetStatement(@NonNull SetStatement asSetStatement) {
+		SetStatementCS csStatement = context.refreshElement(SetStatementCS.class, QVTimperativeCSPackage.Literals.SET_STATEMENT_CS, asSetStatement);
+		csStatement.setReferredVariable((Variable) asSetStatement.getSlotExpression().getReferredVariable());
+		csStatement.setReferredProperty(QVTimperativeUtil.getTargetProperty(asSetStatement));
+		csStatement.setOwnedInitExpression(createExpCS(asSetStatement.getValue()));
+		return csStatement;
+	}
+
+	@Override
 	public ElementCS visitStatement(@NonNull Statement object) {
 		return visiting(object);
 	}
diff --git a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSContainmentVisitor.java b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSContainmentVisitor.java
index e5f2f52ee..0604e4e29 100644
--- a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSContainmentVisitor.java
+++ b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSContainmentVisitor.java
@@ -58,10 +58,10 @@ import org.eclipse.qvtd.pivot.qvtimperative.MappingCall;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingStatement;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.QVTimperativeFactory;
 import org.eclipse.qvtd.pivot.qvtimperative.QVTimperativePackage;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.Statement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.xtext.qvtimperativecs.BottomPatternCS;
@@ -77,6 +77,7 @@ import org.eclipse.qvtd.xtext.qvtimperativecs.ParamDeclarationCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.PatternCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.PredicateCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.PredicateOrAssignmentCS;
+import org.eclipse.qvtd.xtext.qvtimperativecs.SetStatementCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.QueryCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.RealizedVariableCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.TopLevelCS;
@@ -356,7 +357,7 @@ public class QVTimperativeCSContainmentVisitor extends AbstractQVTimperativeCSCo
 			}
 		}
 		else {
-			context.refreshModelElement(PropertyAssignment.class, QVTimperativePackage.Literals.PROPERTY_ASSIGNMENT, csElement);
+			throw new IllegalStateException();
 		}
 		return null;
 	}
@@ -381,6 +382,12 @@ public class QVTimperativeCSContainmentVisitor extends AbstractQVTimperativeCSCo
 	}
 
 	@Override
+	public @Nullable Continuation<?> visitSetStatementCS(@NonNull SetStatementCS csElement) {
+		context.refreshModelElement(SetStatement.class, QVTimperativePackage.Literals.SET_STATEMENT, csElement);
+		return null;
+	}
+
+	@Override
 	public Continuation<?> visitTopLevelCS(@NonNull TopLevelCS csElement) {
 		importPackages(csElement);
 		@NonNull ImperativeModel asModel = refreshRoot(ImperativeModel.class, QVTimperativePackage.Literals.IMPERATIVE_MODEL, csElement);
diff --git a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSPostOrderVisitor.java b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSPostOrderVisitor.java
index 0b77eafbd..38b164cbb 100644
--- a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSPostOrderVisitor.java
+++ b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSPostOrderVisitor.java
@@ -18,6 +18,7 @@ import org.eclipse.jdt.annotation.Nullable;
 import org.eclipse.ocl.pivot.CollectionType;
 import org.eclipse.ocl.pivot.NavigationCallExp;
 import org.eclipse.ocl.pivot.OCLExpression;
+import org.eclipse.ocl.pivot.Property;
 import org.eclipse.ocl.pivot.Type;
 import org.eclipse.ocl.pivot.Variable;
 import org.eclipse.ocl.pivot.VariableExp;
@@ -41,9 +42,9 @@ import org.eclipse.qvtd.pivot.qvtimperative.GuardPattern;
 import org.eclipse.qvtd.pivot.qvtimperative.Mapping;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingCallBinding;
 import org.eclipse.qvtd.pivot.qvtimperative.MappingLoop;
-import org.eclipse.qvtd.pivot.qvtimperative.PropertyAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.QVTimperativeFactory;
 import org.eclipse.qvtd.pivot.qvtimperative.RealizedVariable;
+import org.eclipse.qvtd.pivot.qvtimperative.SetStatement;
 import org.eclipse.qvtd.pivot.qvtimperative.VariableAssignment;
 import org.eclipse.qvtd.pivot.qvtimperative.VariablePredicate;
 import org.eclipse.qvtd.pivot.qvtimperative.utilities.QVTimperativeUtil;
@@ -60,6 +61,7 @@ import org.eclipse.qvtd.xtext.qvtimperativecs.ParamDeclarationCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.PatternCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.PredicateCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.PredicateOrAssignmentCS;
+import org.eclipse.qvtd.xtext.qvtimperativecs.SetStatementCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.QueryCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.RealizeableVariableCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.RealizedVariableCS;
@@ -94,7 +96,7 @@ public class QVTimperativeCSPostOrderVisitor extends AbstractQVTimperativeCSPost
 		super(context);
 	}
 
-	protected @Nullable Assignment refreshPropertyAssignment(@NonNull NavigationCallExp propertyCallExp, @NonNull PredicateOrAssignmentCS csConstraint) {
+	/*	protected @Nullable Statement refreshPropertyAssignment(@NonNull NavigationCallExp propertyCallExp, @NonNull PredicateOrAssignmentCS csConstraint) {
 		@Nullable PropertyAssignment propertyAssignment;
 		//		Property referredProperty = propertyCallExp.getReferredProperty();
 		//		Property oppositeProperty = referredProperty.getOpposite();
@@ -110,7 +112,7 @@ public class QVTimperativeCSPostOrderVisitor extends AbstractQVTimperativeCSPost
 			//			propertyAssignment.setIsOpposite(target instanceof FeatureCallExp);		// FIXME isOpposite
 		}
 		return propertyAssignment;
-	}
+	} */
 
 	protected @Nullable Assignment refreshVariableAssignment(@NonNull VariableExp variableExp, @NonNull PredicateOrAssignmentCS csConstraint) {
 		Assignment assignment = PivotUtil.getPivot(Assignment.class, csConstraint);
@@ -146,7 +148,8 @@ public class QVTimperativeCSPostOrderVisitor extends AbstractQVTimperativeCSPost
 				if (csInitialiser != null) {
 					Assignment assignment = null;
 					if (target instanceof NavigationCallExp) {
-						assignment = refreshPropertyAssignment((NavigationCallExp)target, csConstraint);
+						throw new IllegalStateException();
+						//						assignment = refreshPropertyAssignment((NavigationCallExp)target, csConstraint);
 					}
 					else if (target instanceof VariableExp) {
 						assignment = refreshVariableAssignment((VariableExp)target, csConstraint);
@@ -351,6 +354,23 @@ public class QVTimperativeCSPostOrderVisitor extends AbstractQVTimperativeCSPost
 	}
 
 	@Override
+	public Continuation<?> visitSetStatementCS(@NonNull SetStatementCS csElement) {
+		SetStatement setStatement = PivotUtil.getPivot(SetStatement.class, csElement);
+		if (setStatement != null) {
+			Variable targetVariable = csElement.getReferredVariable();
+			setStatement.setSlotExpression(PivotUtil.createVariableExp(targetVariable));
+			Property targetProperty = csElement.getReferredProperty();
+			ExpCS csInitialiser = csElement.getOwnedInitExpression();
+			OCLExpression target = csInitialiser != null ? context.visitLeft2Right(OCLExpression.class, csInitialiser) : null;
+			setStatement.setTargetProperty(targetProperty);
+			//			propertyAssignment.setIsOpposite(target instanceof FeatureCallExp);		// FIXME isOpposite
+			setStatement.setValue(target);
+			//				pAssignments.add(assignment);
+		}
+		return null;
+	}
+
+	@Override
 	public Continuation<?> visitTopLevelCS(@NonNull TopLevelCS object) {
 		return null;
 	}
diff --git a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSPreOrderVisitor.java b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSPreOrderVisitor.java
index e2e54890e..afecec058 100644
--- a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSPreOrderVisitor.java
+++ b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/cs2as/QVTimperativeCSPreOrderVisitor.java
@@ -52,6 +52,7 @@ import org.eclipse.qvtd.xtext.qvtimperativecs.MappingLoopCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.ParamDeclarationCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.PredicateCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.PredicateOrAssignmentCS;
+import org.eclipse.qvtd.xtext.qvtimperativecs.SetStatementCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.QueryCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.RealizeableVariableCS;
 import org.eclipse.qvtd.xtext.qvtimperativecs.TopLevelCS;
@@ -291,6 +292,11 @@ public class QVTimperativeCSPreOrderVisitor extends AbstractQVTimperativeCSPreOr
 	}
 
 	@Override
+	public Continuation<?> visitSetStatementCS(@NonNull SetStatementCS csElement) {
+		return null;
+	}
+
+	@Override
 	public Continuation<?> visitTopLevelCS(@NonNull TopLevelCS csElement) {
 		return null;
 	}
diff --git a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/formatting/QVTimperativeFormatter.java b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/formatting/QVTimperativeFormatter.java
index a3a76420c..f4e4ecdc6 100644
--- a/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/formatting/QVTimperativeFormatter.java
+++ b/plugins/org.eclipse.qvtd.xtext.qvtimperative/src/org/eclipse/qvtd/xtext/qvtimperative/formatting/QVTimperativeFormatter.java
@@ -29,6 +29,7 @@ import org.eclipse.qvtd.xtext.qvtimperative.services.QVTimperativeGrammarAccess.
 import org.eclipse.qvtd.xtext.qvtimperative.services.QVTimperativeGrammarAccess.QueryCSElements;
 import org.eclipse.qvtd.xtext.qvtimperative.services.QVTimperativeGrammarAccess.RealizedVariableCSElements;
 import org.eclipse.qvtd.xtext.qvtimperative.services.QVTimperativeGrammarAccess.ScopeNameCSElements;
+import org.eclipse.qvtd.xtext.qvtimperative.services.QVTimperativeGrammarAccess.SetStatementCSElements;
 import org.eclipse.qvtd.xtext.qvtimperative.services.QVTimperativeGrammarAccess.SourceBottomPatternCSElements;
 import org.eclipse.qvtd.xtext.qvtimperative.services.QVTimperativeGrammarAccess.SourceDomainCSElements;
 import org.eclipse.qvtd.xtext.qvtimperative.services.QVTimperativeGrammarAccess.SourceGuardPatternCSElements;
@@ -222,8 +223,8 @@ public class QVTimperativeFormatter extends AbstractEssentialOCLFormatter
 			MappingCSElements a = f.getMappingCSAccess();
 			c.setLinewrap(2).before(a.getMapKeyword_2());
 			c.setNoSpace().before(a.getSemicolonKeyword_6_2());
-			c.setNoSpace().between(a.getLeftCurlyBracketKeyword_7(), a.getRightCurlyBracketKeyword_11());
-			setBraces(c, a.getLeftCurlyBracketKeyword_7(), a.getRightCurlyBracketKeyword_11());
+			c.setNoSpace().between(a.getLeftCurlyBracketKeyword_7(), a.getRightCurlyBracketKeyword_12());
+			setBraces(c, a.getLeftCurlyBracketKeyword_7(), a.getRightCurlyBracketKeyword_12());
 			//			c.setLinewrap(2).between(a.getDomainsAssignment_5(), a.getDomainsAssignment_5());
 			c.setLinewrap(1).before(a.getOwnedDomainsAssignment_8());
 			c.setLinewrap(1).before(a.getWhereKeyword_9_0());
@@ -337,6 +338,11 @@ public class QVTimperativeFormatter extends AbstractEssentialOCLFormatter
 			c.setNoSpace().around(a.getColonColonKeyword_2_1());
 		}
 		{
+			SetStatementCSElements a = f.getSetStatementCSAccess();
+			c.setLinewrap(1).before(a.getSetKeyword_0());
+			c.setNoSpace().before(a.getSemicolonKeyword_6());
+		}
+		{
 			SourceBottomPatternCSElements a = f.getSourceBottomPatternCSAccess();
 			c.setNoLinewrap().before(a.getLeftCurlyBracketKeyword_1());
 			c.setLinewrap().after(a.getLeftCurlyBracketKeyword_1());
diff --git a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/QVTiInterpreterTests.java b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/QVTiInterpreterTests.java
index 7bf996340..8eab30e06 100644
--- a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/QVTiInterpreterTests.java
+++ b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/QVTiInterpreterTests.java
@@ -444,6 +444,7 @@ public class QVTiInterpreterTests extends LoadTestCase
 	public void testClassesCS2AS_bug456900() throws Exception {
 		MyQVT myQVT = createQVT();
 		QVTiEnvironmentFactory environmentFactory = myQVT.getEnvironmentFactory();
+		environmentFactory.setEvaluationTracingEnabled(true);
 		MyQvtiExecutor testEvaluator = new MyQvtiExecutor(environmentFactory, "ClassesCS2AS/bug456900", "ClassesCS2AS.qvti");
 		testEvaluator.saveTransformation(null);
 		testEvaluator.loadModel("leftCS", "example_input.xmi");