[500962] Use element rather than collection type for connections

24 files changed, 92 insertions, 99 deletions

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 63b6641b1..7c95484c3 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
@@ -1380,13 +1380,8 @@ public class QVTiCG2JavaVisitor extends CG2JavaVisitor<@NonNull QVTiCodeGenerato
 			return false;
 		}
 		final String iteratorName = getSymbolName(null, "iterator");
-		//		CollectionTypeId abstractCollectionTypeId = (CollectionTypeId)initValue.getASTypeId();
-		//		assert abstractCollectionTypeId != null;
-		//		TypeId abstractElementTypeId = abstractCollectionTypeId.getElementTypeId();
-		//		BoxedDescriptor abstractBoxedDescriptor = context.getBoxedDescriptor(abstractElementTypeId);
-		CollectionTypeId concreteCollectionTypeId = (CollectionTypeId)cgConnectionAssignment.getConnectionVariable().getASTypeId();
-		assert concreteCollectionTypeId != null;
-		TypeId concreteElementTypeId = concreteCollectionTypeId.getElementTypeId();
+		TypeId concreteElementTypeId = cgConnectionAssignment.getConnectionVariable().getASTypeId();
+		assert concreteElementTypeId != null;
 		BoxedDescriptor concreteBoxedDescriptor = context.getBoxedDescriptor(concreteElementTypeId);
 		BoxedDescriptor abstractBoxedDescriptor = concreteBoxedDescriptor;
 		if (!(initValue.getASTypeId() instanceof CollectionTypeId)) {
diff --git a/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvtp2qvts/BasicNodeConnection.java b/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvtp2qvts/BasicNodeConnection.java
index f2211de73..f9ab1e8de 100644
--- a/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvtp2qvts/BasicNodeConnection.java
+++ b/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvtp2qvts/BasicNodeConnection.java
@@ -17,7 +17,6 @@ import java.util.Set;
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
 import org.eclipse.ocl.pivot.CollectionType;
-import org.eclipse.ocl.pivot.CompleteEnvironment;
 import org.eclipse.ocl.pivot.Type;
 import org.eclipse.ocl.pivot.ids.IdResolver;
 import org.eclipse.qvtd.compiler.internal.utilities.SymbolNameBuilder;
@@ -126,11 +125,15 @@ public class BasicNodeConnection extends AbstractConnection<@NonNull Node> imple
 		Type commonType = null;
 		for (@NonNull Node node : getSources()) {
 			Type nodeType = node.getCompleteClass().getPrimaryClass();
-			//			System.out.println("  nodeType " + nodeType);
-			CompleteEnvironment environment = idResolver.getEnvironment();
-			if (!(nodeType instanceof CollectionType)) {		// RealizedVariable accumulated on Connection
-				nodeType = isOrdered() ? environment.getOrderedSetType(nodeType, true, null, null) : environment.getSetType(nodeType, true, null, null);
+			if (nodeType instanceof CollectionType) {
+				nodeType = ((CollectionType)nodeType).getElementType();		// FIXME needed for composed source nodes
+				assert nodeType != null;
 			}
+			//			System.out.println("  nodeType " + nodeType);
+			//			CompleteEnvironment environment = idResolver.getEnvironment();
+			//			if (!(nodeType instanceof CollectionType)) {		// RealizedVariable accumulated on Connection
+			//				nodeType = isOrdered() ? environment.getOrderedSetType(nodeType, true, null, null) : environment.getSetType(nodeType, true, null, null);
+			//			}
 			if (commonType == null) {
 				commonType = nodeType;
 			}
@@ -180,7 +183,7 @@ public class BasicNodeConnection extends AbstractConnection<@NonNull Node> imple
 
 	/**
 	 * Return true if this connections should be ordered since its source could be ordered.
-	 */
+	 *
 	private boolean isOrdered() {
 		boolean isOrdered = false;
 		for (@NonNull Node sourceNode1 : getSources()) {
@@ -195,7 +198,7 @@ public class BasicNodeConnection extends AbstractConnection<@NonNull Node> imple
 			}
 		}
 		return isOrdered;
-	}
+	} */
 
 	/*	@Override
 	public boolean isOutput() {
diff --git a/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/CyclicScheduledRegion2Mapping.java b/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/CyclicScheduledRegion2Mapping.java
index ea2d5c462..b1627d4bf 100644
--- a/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/CyclicScheduledRegion2Mapping.java
+++ b/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/CyclicScheduledRegion2Mapping.java
@@ -121,13 +121,13 @@ public class CyclicScheduledRegion2Mapping extends AbstractScheduledRegion2Mappi
 			//					incoming2outgoing.put(incomingConnection, internallyPassedConnection);
 			Type asType = getConnectionSourcesType(incomingConnection);
 			String localName = getSafeName("«local" + (index > 0 ? Integer.toString(index) : "") + "»");
-			localVariable = helper.createBufferStatement(localName, asType, true, null);
+			localVariable = helper.createBufferStatement(localName, true, asType, true, null);
 			mapping.getOwnedStatements().add(localVariable);
 			connection2variable.put(outgoingConnection, localVariable);
 			//
 			if ((asType instanceof CollectionType) && ((CollectionType)asType).isUnique()) {
 				String newName = getSafeName("«new" + (index > 0 ? Integer.toString(index) : "") + "»");
-				BufferStatement newVariable2 = newVariable = helper.createBufferStatement(newName, asType, true, null);
+				BufferStatement newVariable2 = newVariable = helper.createBufferStatement(newName, true, asType, true, null);
 				mapping.getOwnedStatements().add(newVariable2);
 				connection2variable.put(outgoingConnection, newVariable2);
 			}
diff --git a/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/RootRegion2Mapping.java b/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/RootRegion2Mapping.java
index 5296de421..cfd33221c 100644
--- a/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/RootRegion2Mapping.java
+++ b/plugins/org.eclipse.qvtd.compiler/src/org/eclipse/qvtd/compiler/internal/qvts2qvti/RootRegion2Mapping.java
@@ -123,10 +123,10 @@ public class RootRegion2Mapping extends AbstractScheduledRegion2Mapping
 		return helper.createVariableExp(allInstancesVariable);
 	}
 
-	private @NonNull ConnectionVariable createRootConnectionVariable(@NonNull String name, @NonNull Type type, @Nullable OCLExpression initExpression) {
+	private @NonNull ConnectionVariable createRootConnectionVariable(@NonNull String name, boolean isStrict, @NonNull Type type, @Nullable OCLExpression initExpression) {
 		//		Type variableType = visitor.getEnvironmentFactory().getCompleteEnvironment().getSetType(node.getCompleteClass().getPrimaryClass(), true, null, null);
 		//		assert variableType != null;
-		BufferStatement variable = helper.createBufferStatement(getSafeName(name), type, true, initExpression);
+		BufferStatement variable = helper.createBufferStatement(getSafeName(name), isStrict, type, true, initExpression);
 		mapping.getOwnedStatements().add(variable);
 		//		Variable oldVariable = node2variable.put(node, variable);
 		//		assert oldVariable == null;
@@ -134,7 +134,7 @@ public class RootRegion2Mapping extends AbstractScheduledRegion2Mapping
 	}
 
 	private void createRootConnectionVariables() {
-		List<@NonNull NodeConnection> rootConnections = new ArrayList<@NonNull NodeConnection>(region.getRootConnections());
+		List<@NonNull NodeConnection> rootConnections = new ArrayList<>(region.getRootConnections());
 		Collections.sort(rootConnections, NameUtil.NAMEABLE_COMPARATOR);
 		for (@NonNull NodeConnection rootConnection : rootConnections) {
 			Type commonType = getConnectionSourcesType(rootConnection);
@@ -149,14 +149,10 @@ public class RootRegion2Mapping extends AbstractScheduledRegion2Mapping
 					case 1: initExpression = getFilteredExpression(initExpression, (NavigableEdge) incomingEdges.get(0)); break;
 					default: assert false;
 				}
-				connection2variable.put(rootConnection, createRootConnectionVariable(name, commonType, initExpression));
-			}
-			else if (commonType instanceof CollectionType) {
-				connection2variable.put(rootConnection, createRootConnectionVariable(name, commonType, null));
+				connection2variable.put(rootConnection, createRootConnectionVariable(name, false, commonType, initExpression));
 			}
 			else {
-				CollectionType setType = visitor.getEnvironmentFactory().getCompleteEnvironment().getSetType(commonType, true, null, null);
-				connection2variable.put(rootConnection, createRootConnectionVariable(name, setType, null));
+				connection2variable.put(rootConnection, createRootConnectionVariable(name, false, commonType, null));
 			}
 		}
 	}
diff --git a/plugins/org.eclipse.qvtd.pivot.qvtimperative/model/QVTimperative.ocl b/plugins/org.eclipse.qvtd.pivot.qvtimperative/model/QVTimperative.ocl
index e3d7cb5e7..3ae699d0f 100644
--- a/plugins/org.eclipse.qvtd.pivot.qvtimperative/model/QVTimperative.ocl
+++ b/plugins/org.eclipse.qvtd.pivot.qvtimperative/model/QVTimperative.ocl
@@ -63,9 +63,9 @@ inv NoRealizedVariableNavigations: ownedExpression->closure(oclContents())->sele
 --	if mapping.isToMiddle then area = mapping else area.oclAsType(CoreDomain).isEnforceable endif
 
 context GuardParameterBinding
-inv CheckedTypeIsNotConformant: isCheck implies let elementType = value.type.oclAsType(ocl::CollectionType).elementType in not elementType.conformsTo(boundVariable.type)
-inv UncheckedTypeIsConformant: not isCheck implies let elementType = value.type.oclAsType(ocl::CollectionType).elementType in elementType.conformsTo(boundVariable.type)
-inv CompatibleBinding: let elementType = value.type.oclAsType(ocl::CollectionType).elementType in elementType.conformsTo(boundVariable.type) or boundVariable.type.conformsTo(elementType)
+inv CheckedTypeIsNotConformant: isCheck implies not value.type.conformsTo(boundVariable.type)
+inv UncheckedTypeIsConformant: not isCheck implies value.type.conformsTo(boundVariable.type)
+inv CompatibleBinding: let elementType = value.type in elementType.conformsTo(boundVariable.type) or boundVariable.type.conformsTo(elementType)
 
 context SimpleParameterBinding
 inv CheckedTypeIsNotConformant: isCheck implies not value.type.conformsTo(boundVariable.type)
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 691a5fe23..109b542b4 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
@@ -91,6 +91,7 @@ public class QVTiEvaluationVisitor extends BasicEvaluationVisitor implements IQV
 			Object targetValue = ClassUtil.nonNullState(executor.getValueOf(targetVariable));
 			Connection connectionCollection = (Connection) targetValue;
 			Object values = valueExpression.accept(undecoratedVisitor);
+			assert values != null;
 			//			if (values instanceof Iterable<?>) {
 			//				CollectionValue valuesCollection = ValueUtil.asCollectionValue(values);
 			//				for (Object value : valuesCollection) {
@@ -298,7 +299,7 @@ public class QVTiEvaluationVisitor extends BasicEvaluationVisitor implements IQV
 		assert name != null;
 		if (ownedExpression != null) {
 			Object initValue = ownedExpression.accept(undecoratedVisitor);
-			connection = interval.createConnection(name, (CollectionTypeId) ownedExpression.getTypeId(), object.isIsStrict());
+			connection = interval.createConnection(name, ownedExpression.getTypeId(), object.isIsStrict());
 			if (initValue != null) {
 				for (Object value : (Iterable<?>)initValue) {
 					assert value != null;
@@ -307,7 +308,7 @@ public class QVTiEvaluationVisitor extends BasicEvaluationVisitor implements IQV
 			}
 		}
 		else {
-			connection = interval.createConnection(name, (CollectionTypeId) object.getTypeId(), object.isIsStrict());
+			connection = interval.createConnection(name, object.getTypeId(), object.isIsStrict());
 		}
 		executor.replace(object, connection, false);
 		return true;
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 9bc3175e3..0c78126ff 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
@@ -12,7 +12,6 @@ package org.eclipse.qvtd.pivot.qvtimperative.utilities;
 
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
-import org.eclipse.ocl.pivot.CollectionType;
 import org.eclipse.ocl.pivot.OCLExpression;
 import org.eclipse.ocl.pivot.Type;
 import org.eclipse.ocl.pivot.utilities.ClassUtil;
@@ -65,11 +64,12 @@ public class QVTimperativeHelper extends QVTbaseHelper
 		return mappingParameterBinding;
 	}
 
-	public @NonNull BufferStatement createBufferStatement(@NonNull String name, @NonNull Type asType, boolean isRequired, @Nullable OCLExpression initExpression) {
+	public @NonNull BufferStatement createBufferStatement(@NonNull String name, boolean isStrict, @NonNull Type asType, boolean isRequired, @Nullable OCLExpression initExpression) {
 		BufferStatement asVariable = QVTimperativeFactory.eINSTANCE.createBufferStatement();
 		asVariable.setName(name);
 		asVariable.setType(asType);
 		asVariable.setIsRequired(isRequired);
+		asVariable.setIsStrict(isStrict);
 		asVariable.setOwnedExpression(initExpression);
 		return asVariable;
 	}
@@ -103,8 +103,7 @@ public class QVTimperativeHelper extends QVTbaseHelper
 		GuardParameterBinding mappingParameterBinding = QVTimperativeFactory.eINSTANCE.createGuardParameterBinding();
 		mappingParameterBinding.setBoundVariable(variable);
 		mappingParameterBinding.setValue(value);
-		CollectionType collectionType = (CollectionType) value.getType();
-		Type elementType = collectionType.getElementType();
+		Type elementType = value.getType();
 		Type guardType = ClassUtil.nonNullState(variable.getType());
 		mappingParameterBinding.setIsCheck(!elementType.conformsTo(standardLibrary, guardType));
 		return mappingParameterBinding;
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractConnection.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractConnection.java
index 0a7fce165..cd190bc70 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractConnection.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractConnection.java
@@ -15,14 +15,14 @@ import java.util.List;
 
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 
 public abstract class AbstractConnection implements Connection
 {
 	protected final boolean debugAppends = AbstractTransformer.APPENDS.isActive();
 	protected final @NonNull Interval interval;
 	protected final @NonNull String name;
-	protected final @NonNull CollectionTypeId typeId;
+	protected final @NonNull TypeId typeId;
 
 	/**
 	 * The consumers of each appended value.
@@ -39,7 +39,7 @@ public abstract class AbstractConnection implements Connection
 	 */
 	private boolean isQueued = false;
 
-	protected AbstractConnection(@NonNull Interval interval, @NonNull String name, @NonNull CollectionTypeId typeId) {
+	protected AbstractConnection(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
 		this.interval = interval;
 		this.name = name;
 		this.typeId = typeId;
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractInvocation.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractInvocation.java
index 411abc355..e391c45a5 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractInvocation.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/AbstractInvocation.java
@@ -16,7 +16,7 @@ import java.util.List;
 import java.util.Set;
 
 import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.qvtd.runtime.internal.evaluation.AbstractInvocationInternal;
 
 /**
@@ -68,11 +68,11 @@ public abstract class AbstractInvocation extends AbstractInvocationInternal
 			writeSlot.addSourceInternal(this);
 		}
 
-		protected @NonNull Connection createConnection(@NonNull String name, @NonNull CollectionTypeId typeId, boolean isStrict) {
+		protected @NonNull Connection createConnection(@NonNull String name, @NonNull TypeId typeId, boolean isStrict) {
 			return constructor.getInterval().createConnection(name, typeId, isStrict);
 		}
 
-		protected Connection.@NonNull Incremental createIncrementalConnection(@NonNull String name, @NonNull CollectionTypeId typeId, boolean isStrict) {
+		protected Connection.@NonNull Incremental createIncrementalConnection(@NonNull String name, @NonNull TypeId typeId, boolean isStrict) {
 			return constructor.getInterval().createIncrementalConnection(name, typeId, isStrict);
 		}
 
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Interval.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Interval.java
index 7792f5407..57b96cc18 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Interval.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/Interval.java
@@ -11,7 +11,7 @@
 package org.eclipse.qvtd.runtime.evaluation;
 
 import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.ocl.pivot.utilities.Nameable;
 
 /**
@@ -22,9 +22,9 @@ import org.eclipse.ocl.pivot.utilities.Nameable;
  */
 public interface Interval extends ExecutionVisitable, Nameable
 {
-	@NonNull Connection createConnection(@NonNull String name, @NonNull CollectionTypeId typeId, boolean isStrict);
+	@NonNull Connection createConnection(@NonNull String name, @NonNull TypeId typeId, boolean isStrict);
 
-	Connection.@NonNull Incremental createIncrementalConnection(@NonNull String name, @NonNull CollectionTypeId typeId, boolean isStrict);
+	Connection.@NonNull Incremental createIncrementalConnection(@NonNull String name, @NonNull TypeId typeId, boolean isStrict);
 
 	boolean flush();
 
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SimpleConnection.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SimpleConnection.java
index 962e54793..b53c7744b 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SimpleConnection.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SimpleConnection.java
@@ -11,7 +11,7 @@
 package org.eclipse.qvtd.runtime.evaluation;
 
 import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.qvtd.runtime.internal.evaluation.AbstractConnectionInternal;
 
 /**
@@ -25,7 +25,7 @@ import org.eclipse.qvtd.runtime.internal.evaluation.AbstractConnectionInternal;
  */
 public class SimpleConnection extends AbstractConnectionInternal
 {
-	public SimpleConnection(@NonNull Interval interval, @NonNull String name, @NonNull CollectionTypeId typeId) {
+	public SimpleConnection(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
 		super(interval, name, typeId);
 	}
 }
\ No newline at end of file
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SimpleIncrementalConnection.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SimpleIncrementalConnection.java
index aa9196da9..c9bfb20d8 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SimpleIncrementalConnection.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/SimpleIncrementalConnection.java
@@ -11,7 +11,7 @@
 package org.eclipse.qvtd.runtime.evaluation;
 
 import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.qvtd.runtime.internal.evaluation.IncrementalConnectionInternal;
 
 /**
@@ -25,7 +25,7 @@ import org.eclipse.qvtd.runtime.internal.evaluation.IncrementalConnectionInterna
  */
 public class SimpleIncrementalConnection extends IncrementalConnectionInternal
 {
-	public SimpleIncrementalConnection(@NonNull Interval interval, @NonNull String name, @NonNull CollectionTypeId typeId) {
+	public SimpleIncrementalConnection(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
 		super(interval, name, typeId);
 	}
 }
\ No newline at end of file
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictConnection.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictConnection.java
index 0b1de4cc4..1a86ae7f0 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictConnection.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictConnection.java
@@ -11,7 +11,7 @@
 package org.eclipse.qvtd.runtime.evaluation;
 
 import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.qvtd.runtime.internal.evaluation.StrictConnectionInternal;
 
 /**
@@ -23,7 +23,7 @@ import org.eclipse.qvtd.runtime.internal.evaluation.StrictConnectionInternal;
  */
 public class StrictConnection extends StrictConnectionInternal
 {
-	public StrictConnection(@NonNull Interval interval, @NonNull String name, @NonNull CollectionTypeId typeId) {
+	public StrictConnection(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
 		super(interval, name, typeId);
 	}
 }
\ No newline at end of file
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictIncrementalConnection.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictIncrementalConnection.java
index 971b1678e..9b2eafd17 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictIncrementalConnection.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/evaluation/StrictIncrementalConnection.java
@@ -11,7 +11,7 @@
 package org.eclipse.qvtd.runtime.evaluation;
 
 import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.qvtd.runtime.internal.evaluation.StrictIncrementalConnectionInternal;
 
 /**
@@ -25,7 +25,7 @@ import org.eclipse.qvtd.runtime.internal.evaluation.StrictIncrementalConnectionI
  */
 public class StrictIncrementalConnection extends StrictIncrementalConnectionInternal
 {
-	public StrictIncrementalConnection(@NonNull Interval interval, @NonNull String name, @NonNull CollectionTypeId typeId) {
+	public StrictIncrementalConnection(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
 		super(interval, name, typeId);
 	}
 }
\ No newline at end of file
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractConnectionInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractConnectionInternal.java
index 407e14342..ac67c953c 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractConnectionInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractConnectionInternal.java
@@ -14,7 +14,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.ocl.pivot.utilities.LabelUtil;
 import org.eclipse.qvtd.runtime.evaluation.AbstractConnection;
 import org.eclipse.qvtd.runtime.evaluation.AbstractTransformer;
@@ -33,11 +33,11 @@ import org.eclipse.qvtd.runtime.evaluation.InvocationConstructor;
 public abstract class AbstractConnectionInternal extends AbstractConnection
 {
 	/**
-	 * THe values passed by the coonnection..
+	 * The values passed by the connection..
 	 */
 	protected final @NonNull List<@NonNull Object> values = new ArrayList<>();
 
-	protected AbstractConnectionInternal(@NonNull Interval interval, @NonNull String name, @NonNull CollectionTypeId typeId) {
+	protected AbstractConnectionInternal(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
 		super(interval, name, typeId);
 	}
 
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractIncrementalConnectionInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractIncrementalConnectionInternal.java
index 0afe7171b..f034b519b 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractIncrementalConnectionInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractIncrementalConnectionInternal.java
@@ -17,7 +17,7 @@ import java.util.NoSuchElementException;
 
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.ocl.pivot.utilities.LabelUtil;
 import org.eclipse.qvtd.runtime.evaluation.AbstractConnection;
 import org.eclipse.qvtd.runtime.evaluation.AbstractTransformer;
@@ -55,7 +55,9 @@ public abstract class AbstractIncrementalConnectionInternal extends AbstractConn
 				throw new NoSuchElementException();
 			}
 			cursor = next(cursor+1);
-			return (T) valueAndConsumingInvocations.get(VALUE_INDEX);
+			@SuppressWarnings("unchecked")
+			T castValue = (T) valueAndConsumingInvocations.get(VALUE_INDEX);
+			return castValue;
 		}
 
 		private int next(int i) {
@@ -91,7 +93,7 @@ public abstract class AbstractIncrementalConnectionInternal extends AbstractConn
 	 */
 	protected final @NonNull List<@Nullable List<@NonNull Object>> listOfValueAndConsumingInvocations = new ArrayList<>();
 
-	protected AbstractIncrementalConnectionInternal(@NonNull Interval interval, @NonNull String name, @NonNull CollectionTypeId typeId) {
+	protected AbstractIncrementalConnectionInternal(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
 		super(interval, name, typeId);
 	}
 
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractIntervalInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractIntervalInternal.java
index 34f3e18ec..b5d3fa760 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractIntervalInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractIntervalInternal.java
@@ -15,20 +15,20 @@ import java.util.List;
 
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.qvtd.runtime.evaluation.AbstractConnection;
 import org.eclipse.qvtd.runtime.evaluation.AbstractTransformer;
 import org.eclipse.qvtd.runtime.evaluation.Connection;
-import org.eclipse.qvtd.runtime.evaluation.StrictIncrementalConnection;
 import org.eclipse.qvtd.runtime.evaluation.ExecutionVisitor;
 import org.eclipse.qvtd.runtime.evaluation.Interval;
 import org.eclipse.qvtd.runtime.evaluation.Invocation;
 import org.eclipse.qvtd.runtime.evaluation.InvocationFailedException;
 import org.eclipse.qvtd.runtime.evaluation.InvocationManager;
 import org.eclipse.qvtd.runtime.evaluation.SimpleConnection;
+import org.eclipse.qvtd.runtime.evaluation.SimpleIncrementalConnection;
 import org.eclipse.qvtd.runtime.evaluation.SlotState;
 import org.eclipse.qvtd.runtime.evaluation.StrictConnection;
-import org.eclipse.qvtd.runtime.evaluation.SimpleIncrementalConnection;
+import org.eclipse.qvtd.runtime.evaluation.StrictIncrementalConnection;
 
 /**
  * AbstractIntervalInternal provides the shared implementation of the intrusive blocked/waiting linked list functionality.
@@ -100,7 +100,7 @@ public abstract class AbstractIntervalInternal implements Interval
 	}
 
 	@Override
-	public @NonNull Connection createConnection(@NonNull String name, @NonNull CollectionTypeId typeId, boolean isStrict) {
+	public @NonNull Connection createConnection(@NonNull String name, @NonNull TypeId typeId, boolean isStrict) {
 		Connection connection;
 		if (isStrict) {
 			connection = new StrictConnection(this, name, typeId);
@@ -113,7 +113,7 @@ public abstract class AbstractIntervalInternal implements Interval
 	}
 
 	@Override
-	public Connection.@NonNull Incremental createIncrementalConnection(@NonNull String name, @NonNull CollectionTypeId typeId, boolean isStrict) {
+	public Connection.@NonNull Incremental createIncrementalConnection(@NonNull String name, @NonNull TypeId typeId, boolean isStrict) {
 		Connection.Incremental connection;
 		if (isStrict) {
 			connection = new StrictIncrementalConnection(this, name, typeId);
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractTransformerInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractTransformerInternal.java
index ba8d99690..775347860 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractTransformerInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/AbstractTransformerInternal.java
@@ -528,7 +528,7 @@ public abstract class AbstractTransformerInternal extends AbstractModelManager i
 		models[modelIndex].addRootObjects(eRootObjects);
 	}
 
-	protected @NonNull Connection createConnection(@NonNull String name, @NonNull CollectionTypeId typeId, boolean isStrict) {
+	protected @NonNull Connection createConnection(@NonNull String name, @NonNull TypeId typeId, boolean isStrict) {
 		return invocationManager.getRootInterval().createConnection(name, typeId, isStrict);
 	}
 
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalConnectionInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalConnectionInternal.java
index 4a0544b1a..b847fd50f 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalConnectionInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/IncrementalConnectionInternal.java
@@ -14,7 +14,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.ocl.pivot.utilities.LabelUtil;
 import org.eclipse.qvtd.runtime.evaluation.AbstractInvocation;
 import org.eclipse.qvtd.runtime.evaluation.AbstractTransformer;
@@ -32,7 +32,7 @@ import org.eclipse.qvtd.runtime.evaluation.Invocation;
  */
 public class IncrementalConnectionInternal extends AbstractIncrementalConnectionInternal
 {
-	protected IncrementalConnectionInternal(@NonNull Interval interval, @NonNull String name, @NonNull CollectionTypeId typeId) {
+	protected IncrementalConnectionInternal(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
 		super(interval, name, typeId);
 	}
 
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictConnectionInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictConnectionInternal.java
index 31e9fca17..131889241 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictConnectionInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictConnectionInternal.java
@@ -14,7 +14,7 @@ import java.util.HashSet;
 import java.util.Set;
 
 import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.ocl.pivot.utilities.LabelUtil;
 import org.eclipse.qvtd.runtime.evaluation.AbstractTransformer;
 import org.eclipse.qvtd.runtime.evaluation.Interval;
@@ -33,7 +33,7 @@ public abstract class StrictConnectionInternal extends AbstractConnectionInterna
 	 */
 	private /*@LazyNonNull*/ Set<@NonNull Object> uniqueValues = null;
 
-	protected StrictConnectionInternal(@NonNull Interval interval, @NonNull String name, @NonNull CollectionTypeId typeId) {
+	protected StrictConnectionInternal(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
 		super(interval, name, typeId);
 	}
 
diff --git a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictIncrementalConnectionInternal.java b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictIncrementalConnectionInternal.java
index c46d387ea..9eb2eef62 100644
--- a/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictIncrementalConnectionInternal.java
+++ b/plugins/org.eclipse.qvtd.runtime/src/org/eclipse/qvtd/runtime/internal/evaluation/StrictIncrementalConnectionInternal.java
@@ -16,7 +16,7 @@ import java.util.List;
 import java.util.Map;
 
 import org.eclipse.jdt.annotation.NonNull;
-import org.eclipse.ocl.pivot.ids.CollectionTypeId;
+import org.eclipse.ocl.pivot.ids.TypeId;
 import org.eclipse.ocl.pivot.utilities.LabelUtil;
 import org.eclipse.qvtd.runtime.evaluation.AbstractInvocation;
 import org.eclipse.qvtd.runtime.evaluation.AbstractTransformer;
@@ -37,7 +37,7 @@ public abstract class StrictIncrementalConnectionInternal extends AbstractIncrem
 	 */
 	private final @NonNull Map<@NonNull Object, @NonNull List<@NonNull Object>> uniqueValues2valueAndConsumingInvocations = new HashMap<>();
 
-	protected StrictIncrementalConnectionInternal(@NonNull Interval interval, @NonNull String name, @NonNull CollectionTypeId typeId) {
+	protected StrictIncrementalConnectionInternal(@NonNull Interval interval, @NonNull String name, @NonNull TypeId typeId) {
 		super(interval, name, typeId);
 	}
 
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 7a8e37c43..9d0cbf25e 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
@@ -131,7 +131,17 @@ public class QVTimperativeCSPostOrderVisitor extends AbstractQVTimperativeCSPost
 				OCLExpression target = context.visitLeft2Right(OCLExpression.class, expression);
 				asOutStatement.setOwnedExpression(target);
 				if ((csElement.getOwnedType() == null) && (target != null)) {
-					context.setType(asOutStatement, target.getType(), target.isIsRequired(), target.getTypeValue());
+					Type targetType = target.getType();
+					boolean isRequired = target.isIsRequired();
+					if (targetType instanceof CollectionType) {
+						CollectionType collectionType = (CollectionType)targetType;
+						targetType = collectionType.getElementType();
+						isRequired = collectionType.isIsNullFree();
+					}
+					// FIXME else => error
+					// FIXME !isRequired => error
+					// FIXME isStrict
+					context.setType(asOutStatement, targetType, isRequired, target.getTypeValue());
 				}
 			}
 		}
diff --git a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/KiamaRewrite/KiamaRewrite.qvti b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/KiamaRewrite/KiamaRewrite.qvti
index 5f33d2710..aea399553 100644
--- a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/KiamaRewrite/KiamaRewrite.qvti
+++ b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/KiamaRewrite/KiamaRewrite.qvti
@@ -11,10 +11,9 @@ map __root__ in KiamaRewrite_qvtp_qvtcas
 {
 	var roots : Set(ocl::OclElement) := leftCS.rootObjects();
 	var _'«child-NumCS»' : Set(kiamacs::NumCS) := roots->selectByKind(kiamacs::NumCS);
-	buffer ji_NumCS1 : Set(kiamacs::NumCS) := _'«child-NumCS»';
+	buffer ji_NumCS1 : kiamacs::NumCS := _'«child-NumCS»';
 	var _'«child-PlusCS»' : Set(kiamacs::PlusCS) := roots->selectByKind(kiamacs::PlusCS);
-	buffer ji_PlusCS1 : Set(kiamacs::PlusCS) := _'«child-PlusCS»';
-	buffer ji_PlusCS_31 : Set(kiamacs::PlusCS) := _'«child-PlusCS»';
+	buffer ji_PlusCS1 : kiamacs::PlusCS := _'«child-PlusCS»';
 	var _'«child-TopCS»' : Set(kiamacs::TopCS) := roots->selectByKind(kiamacs::TopCS);
 	var ji_TopCS1 : Set(kiamacs::TopCS) := _'«child-TopCS»';
 	for loop0 : kiamacs::TopCS in ji_TopCS1 {
@@ -26,11 +25,10 @@ map __root__ in KiamaRewrite_qvtp_qvtcas
 		call r_TopCS_node {
 			ji_NumCS appendsTo ji_NumCS1;
 			ji_PlusCS appendsTo ji_PlusCS1;
-			ji_PlusCS_3 appendsTo ji_PlusCS_31;
 			_'«parent»' iterates loop0;
 		}
 	}
-	for loop0 : kiamacs::PlusCS in ji_PlusCS_31 {
+	for loop0 : kiamacs::PlusCS in ji_PlusCS1 {
 		call r__PlusCS {
 			ji_NumCS appendsTo ji_NumCS1;
 			ji_PlusCS appendsTo ji_PlusCS1;
@@ -192,8 +190,8 @@ map m_TopCS_ast_node in KiamaRewrite_qvtp_qvtcas
 
 map r_PlusCS_left in KiamaRewrite_qvtp_qvtcas
 {
-	append ji_PlusCS : Set(kiamacs::PlusCS);
-	append ji_NumCS : Set(kiamacs::NumCS);
+	append ji_PlusCS : kiamacs::PlusCS;
+	append ji_NumCS : kiamacs::NumCS;
 	in:leftCS _'«parent»' : PlusCS;
 	var allChildren : Set(kiamacs::NodeCS) := _'«parent»'.left.oclAsSet();
 	var _'«child-PlusCS»' : Set(kiamacs::PlusCS) := allChildren->selectByKind(kiamacs::PlusCS);
@@ -211,8 +209,8 @@ map r_PlusCS_left in KiamaRewrite_qvtp_qvtcas
 
 map r_PlusCS_right in KiamaRewrite_qvtp_qvtcas
 {
-	append ji_PlusCS : Set(kiamacs::PlusCS);
-	append ji_NumCS : Set(kiamacs::NumCS);
+	append ji_PlusCS : kiamacs::PlusCS;
+	append ji_NumCS : kiamacs::NumCS;
 	in:leftCS _'«parent»' : PlusCS;
 	var allChildren : Set(kiamacs::NodeCS) := _'«parent»'.right.oclAsSet();
 	var _'«child-PlusCS»' : Set(kiamacs::PlusCS) := allChildren->selectByKind(kiamacs::PlusCS);
@@ -230,9 +228,9 @@ map r_PlusCS_right in KiamaRewrite_qvtp_qvtcas
 
 map r_TopCS_node in KiamaRewrite_qvtp_qvtcas
 {
-	append ji_PlusCS : Set(kiamacs::PlusCS);
-	append ji_PlusCS_3 : Set(kiamacs::PlusCS);
-	append ji_NumCS : Set(kiamacs::NumCS);
+	append ji_PlusCS : kiamacs::PlusCS;
+	append ji_PlusCS_3 : kiamacs::PlusCS;
+	append ji_NumCS : kiamacs::NumCS;
 	guard:leftCS _'«parent»' : TopCS;
 	var allChildren : Set(kiamacs::NodeCS) := _'«parent»'.node.oclAsSet();
 	var _'«child-PlusCS»' : Set(kiamacs::PlusCS) := allChildren->selectByKind(kiamacs::PlusCS);
@@ -244,28 +242,17 @@ map r_TopCS_node in KiamaRewrite_qvtp_qvtcas
 
 strict map r__PlusCS in KiamaRewrite_qvtp_qvtcas
 {
-	append ji_PlusCS : Set(kiamacs::PlusCS);
-	append ji_NumCS : Set(kiamacs::NumCS);
+	append ji_PlusCS : kiamacs::PlusCS;
+	append ji_NumCS : kiamacs::NumCS;
 	guard:leftCS _'«head»' : PlusCS;
-	buffer _'«local»' : Set(kiamacs::PlusCS);
-	buffer _'«new»' : Set(kiamacs::PlusCS);
 	call r_PlusCS_left {
 		ji_NumCS appendsTo ji_NumCS;
-		 ji_PlusCS appendsTo _'«local»';
+		 ji_PlusCS appendsTo ji_PlusCS;
 		_'«parent»' uses _'«head»';
 	}
 	call r_PlusCS_right {
 		ji_NumCS appendsTo ji_NumCS;
-		 ji_PlusCS appendsTo _'«local»';
+		 ji_PlusCS appendsTo ji_PlusCS;
 		_'«parent»' uses _'«head»';
 	}
-	add _'«new»' += _'«local»'->excludingAll(ji_PlusCS);
-	add ji_PlusCS += _'«new»';
-	for loop0 : kiamacs::PlusCS in _'«new»' {
-		call r__PlusCS {
-			ji_NumCS appendsTo ji_NumCS;
-			ji_PlusCS appendsTo ji_PlusCS;
-			_'«head»' iterates  loop0;
-		}
-	}
 }
\ No newline at end of file
diff --git a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/Tree2TallTreeInstall.qvti b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/Tree2TallTreeInstall.qvti
index f4e53f6de..e20da977a 100644
--- a/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/Tree2TallTreeInstall.qvti
+++ b/tests/org.eclipse.qvtd.xtext.qvtimperative.tests/src/org/eclipse/qvtd/xtext/qvtimperative/tests/Tree2TallTree/Tree2TallTreeInstall.qvti
@@ -10,7 +10,7 @@ transformation Tree2TallTreeInstall {
 
 map __root__ in Tree2TallTreeInstall {
     buffer nodes := tree.objectsOfKind(Node)->sortedBy(name);
-    buffer node2tallNodes : Sequence(tree2talltree::Node2TallNode);
+    buffer node2tallNodes : tree2talltree::Node2TallNode;
     install Node2MiddleNode {
         node consumes nodes;
         node2tallNodes appendsTo node2tallNodes;	
@@ -25,7 +25,7 @@ map __root__ in Tree2TallTreeInstall {
 
 map Node2MiddleNode in Tree2TallTreeInstall {
 	guard:tree node : Node; 
-	append node2tallNodes : Sequence(tree2talltree::Node2TallNode); 
+	append node2tallNodes : tree2talltree::Node2TallNode; 
 	new:tree2talltree node2tallNode : Node2TallNode;
 	set node2tallNode.node := node;
 	set node2tallNode.name := node.name;