diff --git a/teavm-core/src/main/java/org/teavm/dependency/DataFlowGraphBuilder.java b/teavm-core/src/main/java/org/teavm/dependency/DataFlowGraphBuilder.java
index 7fb34216b..882000dfc 100644
--- a/teavm-core/src/main/java/org/teavm/dependency/DataFlowGraphBuilder.java
+++ b/teavm-core/src/main/java/org/teavm/dependency/DataFlowGraphBuilder.java
@@ -36,14 +36,20 @@ public class DataFlowGraphBuilder implements InstructionReader {
     private ObjectIntMap<MethodReference> methodNodes = new ObjectIntOpenHashMap<>();
     private ObjectIntMap<FieldReference> fieldNodes = new ObjectIntOpenHashMap<>();
     private int[] arrayNodes;
+    private int returnIndex = -1;
+    private int exceptionIndex;
 
     public void important(int node) {
         importantNodes.add(node);
     }
 
-    public int[] buildMapping(ProgramReader program, int paramCount) {
+    public int[] buildMapping(ProgramReader program, int paramCount, boolean needsReturn) {
         lastIndex = program.variableCount();
         arrayNodes = new int[lastIndex];
+        if (needsReturn) {
+            returnIndex = lastIndex++;
+        }
+        exceptionIndex = lastIndex++;
         Arrays.fill(arrayNodes, -1);
         for (int i = 0; i < program.basicBlockCount(); ++i) {
             BasicBlockReader block = program.basicBlockAt(i);
@@ -52,6 +58,11 @@ public class DataFlowGraphBuilder implements InstructionReader {
                     builder.addEdge(incoming.getValue().getIndex(), phi.getReceiver().getIndex());
                 }
             }
+            for (TryCatchBlockReader tryCatch : block.readTryCatchBlocks()) {
+                if (tryCatch.getExceptionVariable() != null) {
+                    important(tryCatch.getExceptionVariable().getIndex());
+                }
+            }
             block.readAllInstructions(this);
         }
         Graph graph = builder.build();
@@ -76,6 +87,17 @@ public class DataFlowGraphBuilder implements InstructionReader {
                     importantNodes.add(newCls);
                 }
             }
+            for (int succ : graph.outgoingEdges(i)) {
+                boolean succImportant = importantNodes.contains(classes.find(succ));
+                boolean nodeImportant = importantNodes.contains(classes.find(i));
+                if (succImportant && nodeImportant) {
+                    continue;
+                }
+                int newCls = classes.union(succ, i);
+                if (nodeImportant || succImportant) {
+                    importantNodes.add(newCls);
+                }
+            }
         }
 
         int[][] sccs = GraphUtils.findStronglyConnectedComponents(graph, startNodes.getAll());
@@ -88,7 +110,25 @@ public class DataFlowGraphBuilder implements InstructionReader {
                 last = last < 0 ? node : classes.union(node, last);
             }
         }
-        return classes.pack(program.variableCount());
+
+        int[] classMap = new int[classes.size()];
+        Arrays.fill(classMap, -1);
+        int[] result = new int[program.variableCount()];
+        int classCount = 0;
+        for (int i = 0; i < program.variableCount(); ++i) {
+            int cls = classes.find(i);
+            if (!importantNodes.contains(cls)) {
+                result[i] = -1;
+                continue;
+            }
+            int packedCls = classMap[cls];
+            if (packedCls < 0) {
+                packedCls = classCount++;
+                classMap[cls] = packedCls;
+            }
+            result[i] = packedCls;
+        }
+        return result;
     }
 
     @Override
@@ -178,14 +218,16 @@ public class DataFlowGraphBuilder implements InstructionReader {
 
     @Override
     public void exit(VariableReader valueToReturn) {
-        if (valueToReturn != null) {
-            important(valueToReturn.getIndex());
+        if (valueToReturn != null && returnIndex >= 0) {
+            important(returnIndex);
+            builder.addEdge(valueToReturn.getIndex(), returnIndex);
         }
     }
 
     @Override
     public void raise(VariableReader exception) {
-        important(exception.getIndex());
+        builder.addEdge(exception.getIndex(), exceptionIndex);
+        important(exceptionIndex);
     }
 
     @Override
@@ -212,13 +254,18 @@ public class DataFlowGraphBuilder implements InstructionReader {
 
     @Override
     public void getField(VariableReader receiver, VariableReader instance, FieldReference field, ValueType fieldType) {
+        if (fieldType instanceof ValueType.Primitive) {
+            return;
+        }
         int fieldNode = getFieldNode(field);
         builder.addEdge(fieldNode, receiver.getIndex());
     }
 
-
     @Override
-    public void putField(VariableReader instance, FieldReference field, VariableReader value) {
+    public void putField(VariableReader instance, FieldReference field, VariableReader value, ValueType fieldType) {
+        if (fieldType instanceof ValueType.Primitive) {
+            return;
+        }
         int fieldNode = getFieldNode(field);
         builder.addEdge(value.getIndex(), fieldNode);
     }
@@ -274,7 +321,18 @@ public class DataFlowGraphBuilder implements InstructionReader {
     public void invoke(VariableReader receiver, VariableReader instance, MethodReference method,
             List<? extends VariableReader> arguments, InvocationType type) {
         if (receiver != null) {
-            builder.addEdge(getMethodNode(method), receiver.getIndex());
+            if (!(method.getReturnType() instanceof ValueType.Primitive)) {
+                builder.addEdge(getMethodNode(method), receiver.getIndex());
+            }
+        }
+        ValueType[] paramTypes = method.getParameterTypes();
+        for (int i = 0; i < paramTypes.length; ++i) {
+            if (!(paramTypes[i] instanceof ValueType.Primitive)) {
+                important(arguments.get(i).getIndex());
+            }
+        }
+        if (instance != null) {
+            important(instance.getIndex());
         }
     }
 
@@ -293,9 +351,11 @@ public class DataFlowGraphBuilder implements InstructionReader {
 
     @Override
     public void monitorEnter(VariableReader objectRef) {
+        important(objectRef.getIndex());
     }
 
     @Override
     public void monitorExit(VariableReader objectRef) {
+        important(objectRef.getIndex());
     }
 }
diff --git a/teavm-core/src/main/java/org/teavm/dependency/DependencyChecker.java b/teavm-core/src/main/java/org/teavm/dependency/DependencyChecker.java
index 3174539ca..f2b9e96df 100644
--- a/teavm-core/src/main/java/org/teavm/dependency/DependencyChecker.java
+++ b/teavm-core/src/main/java/org/teavm/dependency/DependencyChecker.java
@@ -62,6 +62,8 @@ public class DependencyChecker implements DependencyInfo {
     private Diagnostics diagnostics;
     DefaultCallGraph callGraph = new DefaultCallGraph();
     private DependencyAgent agent;
+    List<DependencyNode> nodes = new ArrayList<>();
+    List<BitSet> typeBitSets = new ArrayList<>();
 
     public DependencyChecker(ClassReaderSource classSource, ClassLoader classLoader, ServiceRepository services,
             Diagnostics diagnostics) {
@@ -128,13 +130,16 @@ public class DependencyChecker implements DependencyInfo {
         if (type == null) {
             type = new DependencyType(this, name, types.size());
             types.add(type);
+            typeBitSets.add(new BitSet(nodes.size()));
             typeMap.put(name, type);
         }
         return type;
     }
 
     public DependencyNode createNode() {
-        return new DependencyNode(this);
+        DependencyNode node = new DependencyNode(this, nodes.size());
+        nodes.add(node);
+        return node;
     }
 
     @Override
@@ -336,11 +341,9 @@ public class DependencyChecker implements DependencyInfo {
     private MethodDependency createMethodDep(MethodReference methodRef, MethodReader method) {
         ValueType[] arguments = methodRef.getParameterTypes();
         int paramCount = arguments.length + 1;
-        int varCount = Math.max(paramCount, method != null && method.getProgram() != null ?
-                method.getProgram().variableCount() : 0);
-        DependencyNode[] parameterNodes = new DependencyNode[varCount];
-        for (int i = 0; i < varCount; ++i) {
-            parameterNodes[i] = new DependencyNode(this);
+        DependencyNode[] parameterNodes = new DependencyNode[arguments.length + 1];
+        for (int i = 0; i < parameterNodes.length; ++i) {
+            parameterNodes[i] = createNode();
             if (shouldLog) {
                 parameterNodes[i].setTag(methodRef + ":" + i);
             }
@@ -349,7 +352,7 @@ public class DependencyChecker implements DependencyInfo {
         if (methodRef.getDescriptor().getResultType() == ValueType.VOID) {
             resultNode = null;
         } else {
-            resultNode = new DependencyNode(this);
+            resultNode = createNode();
             if (shouldLog) {
                 resultNode.setTag(methodRef + ":RESULT");
             }
@@ -431,7 +434,7 @@ public class DependencyChecker implements DependencyInfo {
     }
 
     private FieldDependency createFieldNode(final FieldReference fieldRef, FieldReader field) {
-        DependencyNode node = new DependencyNode(this);
+        DependencyNode node = createNode();
         if (shouldLog) {
             node.setTag(fieldRef.getClassName() + "#" + fieldRef.getFieldName());
         }
@@ -501,6 +504,7 @@ public class DependencyChecker implements DependencyInfo {
                 index = 0;
             }
         }
+        return;
     }
 
     public <T> T getService(Class<T> type) {
diff --git a/teavm-core/src/main/java/org/teavm/dependency/DependencyGraphBuilder.java b/teavm-core/src/main/java/org/teavm/dependency/DependencyGraphBuilder.java
index cad81ed31..159d30425 100644
--- a/teavm-core/src/main/java/org/teavm/dependency/DependencyGraphBuilder.java
+++ b/teavm-core/src/main/java/org/teavm/dependency/DependencyGraphBuilder.java
@@ -15,6 +15,7 @@
  */
 package org.teavm.dependency;
 
+import java.util.Arrays;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
@@ -48,20 +49,29 @@ class DependencyGraphBuilder {
         }
         program = method.getProgram();
         if (DependencyChecker.shouldLog) {
-            System.out.println("Method achieved: " + method.getReference());
+            System.out.println("Method reached: " + method.getReference());
             System.out.println(new ListingBuilder().buildListing(program, "    "));
         }
         resultNode = dep.getResult();
 
-        DependencyNode[] origNodes = dep.getVariables();
         DataFlowGraphBuilder dfgBuilder = new DataFlowGraphBuilder();
         for (int i = 0; i < dep.getParameterCount(); ++i) {
             dfgBuilder.important(i);
         }
-        int[] nodeMapping = dfgBuilder.buildMapping(program, dep.getParameterCount());
-        nodes = new DependencyNode[origNodes.length];
+        int[] nodeMapping = dfgBuilder.buildMapping(program, dep.getParameterCount(),
+                !(method.getResultType() instanceof ValueType.Primitive) && method.getResultType() != ValueType.VOID);
+        int nodeClassCount = 0;
+        for (int i = 0; i < nodeMapping.length; ++i) {
+            nodeClassCount = Math.max(nodeClassCount, nodeMapping[i] + 1);
+        }
+        DependencyNode[] nodeClasses = Arrays.copyOf(dep.getVariables(), nodeClassCount);
+        for (int i = dep.getVariableCount(); i < nodeClasses.length; ++i) {
+            nodeClasses[i] = dependencyChecker.createNode();
+        }
+        nodes = new DependencyNode[dep.getMethod().getProgram().variableCount()];
         for (int i = 0; i < nodes.length; ++i) {
-            nodes[i] = origNodes[nodeMapping[i]];
+            int mappedNode = nodeMapping[i];
+            nodes[i] = mappedNode >= 0 ? nodeClasses[mappedNode] : null;
         }
         dep.setVariables(nodes);
 
@@ -71,7 +81,11 @@ class DependencyGraphBuilder {
             block.readAllInstructions(reader);
             for (PhiReader phi : block.readPhis()) {
                 for (IncomingReader incoming : phi.readIncomings()) {
-                    nodes[incoming.getValue().getIndex()].connect(nodes[phi.getReceiver().getIndex()]);
+                    DependencyNode incomingNode = nodes[incoming.getValue().getIndex()];
+                    DependencyNode receiverNode = nodes[phi.getReceiver().getIndex()];
+                    if (incomingNode != null || receiverNode != null) {
+                        nodes[incoming.getValue().getIndex()].connect(nodes[phi.getReceiver().getIndex()]);
+                    }
                 }
             }
             for (TryCatchBlockReader tryCatch : block.readTryCatchBlocks()) {
@@ -169,7 +183,9 @@ class DependencyGraphBuilder {
                 methodDep.use();
                 DependencyNode[] targetParams = methodDep.getVariables();
                 for (int i = 0; i < parameters.length; ++i) {
-                    parameters[i].connect(targetParams[i]);
+                    if (parameters[i] != null) {
+                        parameters[i].connect(targetParams[i]);
+                    }
                 }
                 if (result != null && methodDep.getResult() != null) {
                     methodDep.getResult().connect(result);
@@ -211,7 +227,10 @@ class DependencyGraphBuilder {
 
         @Override
         public void classConstant(VariableReader receiver, ValueType cst) {
-            nodes[receiver.getIndex()].propagate(dependencyChecker.getType("java.lang.Class"));
+            DependencyNode node = nodes[receiver.getIndex()];
+            if (node != null) {
+                node.propagate(dependencyChecker.getType("java.lang.Class"));
+            }
             while (cst instanceof ValueType.Array) {
                 cst = ((ValueType.Array)cst).getItemType();
             }
@@ -243,7 +262,10 @@ class DependencyGraphBuilder {
 
         @Override
         public void stringConstant(VariableReader receiver, String cst) {
-            nodes[receiver.getIndex()].propagate(dependencyChecker.getType("java.lang.String"));
+            DependencyNode node = nodes[receiver.getIndex()];
+            if (node != null) {
+                node.propagate(dependencyChecker.getType("java.lang.String"));
+            }
             MethodDependency method = dependencyChecker.linkMethod(new MethodReference(String.class,
                     "<init>", char[].class, void.class), new CallLocation(caller.getMethod(), currentLocation));
             method.use();
@@ -262,7 +284,9 @@ class DependencyGraphBuilder {
         public void assign(VariableReader receiver, VariableReader assignee) {
             DependencyNode valueNode = nodes[assignee.getIndex()];
             DependencyNode receiverNode = nodes[receiver.getIndex()];
-            valueNode.connect(receiverNode);
+            if (valueNode != null && receiverNode != null) {
+                valueNode.connect(receiverNode);
+            }
         }
 
         @Override
@@ -319,7 +343,10 @@ class DependencyGraphBuilder {
         @Override
         public void exit(VariableReader valueToReturn) {
             if (valueToReturn != null) {
-                nodes[valueToReturn.getIndex()].connect(resultNode);
+                DependencyNode node = nodes[valueToReturn.getIndex()];
+                if (node != null) {
+                    node.connect(resultNode);
+                }
             }
         }
 
@@ -330,7 +357,10 @@ class DependencyGraphBuilder {
 
         @Override
         public void createArray(VariableReader receiver, ValueType itemType, VariableReader size) {
-            nodes[receiver.getIndex()].propagate(dependencyChecker.getType("[" + itemType));
+            DependencyNode node = nodes[receiver.getIndex()];
+            if (node != null) {
+                node.propagate(dependencyChecker.getType("[" + itemType));
+            }
             String className = extractClassName(itemType);
             if (className != null) {
                 dependencyChecker.linkClass(className, new CallLocation(caller.getMethod(), currentLocation));
@@ -361,6 +391,9 @@ class DependencyGraphBuilder {
             sb.append(itemTypeStr);
             DependencyNode node = nodes[receiver.getIndex()];
             for (int i = 0; i < dimensions.size(); ++i) {
+                if (node == null) {
+                    break;
+                }
                 node.propagate(dependencyChecker.getType(sb.substring(i, sb.length())));
                 node = node.getArrayItem();
             }
@@ -373,25 +406,37 @@ class DependencyGraphBuilder {
         @Override
         public void create(VariableReader receiver, String type) {
             dependencyChecker.linkClass(type, new CallLocation(caller.getMethod(), currentLocation));
-            nodes[receiver.getIndex()].propagate(dependencyChecker.getType(type));
+            DependencyNode node = nodes[receiver.getIndex()];
+            if (node != null) {
+                node.propagate(dependencyChecker.getType(type));
+            }
         }
 
         @Override
         public void getField(VariableReader receiver, VariableReader instance, FieldReference field,
                 ValueType fieldType) {
-            FieldDependency fieldDep = dependencyChecker.linkField(field,
-                    new CallLocation(caller.getMethod(), currentLocation));
-            DependencyNode receiverNode = nodes[receiver.getIndex()];
-            fieldDep.getValue().connect(receiverNode);
+            if (!(fieldType instanceof ValueType.Primitive)) {
+                FieldDependency fieldDep = dependencyChecker.linkField(field,
+                        new CallLocation(caller.getMethod(), currentLocation));
+                DependencyNode receiverNode = nodes[receiver.getIndex()];
+                if (receiverNode != null) {
+                    fieldDep.getValue().connect(receiverNode);
+                }
+            }
             initClass(field.getClassName());
         }
 
         @Override
-        public void putField(VariableReader instance, FieldReference field, VariableReader value) {
-            FieldDependency fieldDep = dependencyChecker.linkField(field,
-                    new CallLocation(caller.getMethod(), currentLocation));
-            DependencyNode valueNode = nodes[value.getIndex()];
-            valueNode.connect(fieldDep.getValue());
+        public void putField(VariableReader instance, FieldReference field, VariableReader value,
+                ValueType fieldType) {
+            if (!(fieldType instanceof ValueType.Primitive)) {
+                FieldDependency fieldDep = dependencyChecker.linkField(field,
+                        new CallLocation(caller.getMethod(), currentLocation));
+                DependencyNode valueNode = nodes[value.getIndex()];
+                if (valueNode != null) {
+                    valueNode.connect(fieldDep.getValue());
+                }
+            }
             initClass(field.getClassName());
         }
 
@@ -403,33 +448,41 @@ class DependencyGraphBuilder {
         public void cloneArray(VariableReader receiver, VariableReader array) {
             DependencyNode arrayNode = nodes[array.getIndex()];
             final DependencyNode receiverNode = nodes[receiver.getIndex()];
-            arrayNode.addConsumer(new DependencyConsumer() {
-                @Override public void consume(DependencyType type) {
-                    receiverNode.propagate(type);
-                }
-            });
-            arrayNode.getArrayItem().connect(receiverNode.getArrayItem());
+            if (arrayNode != null && receiverNode != null) {
+                arrayNode.addConsumer(new DependencyConsumer() {
+                    @Override public void consume(DependencyType type) {
+                        receiverNode.propagate(type);
+                    }
+                });
+                arrayNode.getArrayItem().connect(receiverNode.getArrayItem());
+            }
         }
 
         @Override
         public void unwrapArray(VariableReader receiver, VariableReader array, ArrayElementType elementType) {
             DependencyNode arrayNode = nodes[array.getIndex()];
             DependencyNode receiverNode = nodes[receiver.getIndex()];
-            arrayNode.connect(receiverNode);
+            if (arrayNode != null && receiverNode != null) {
+                arrayNode.connect(receiverNode);
+            }
         }
 
         @Override
         public void getElement(VariableReader receiver, VariableReader array, VariableReader index) {
             DependencyNode arrayNode = nodes[array.getIndex()];
             DependencyNode receiverNode = nodes[receiver.getIndex()];
-            arrayNode.getArrayItem().connect(receiverNode);
+            if (arrayNode != null && receiverNode != null) {
+                arrayNode.getArrayItem().connect(receiverNode);
+            }
         }
 
         @Override
         public void putElement(VariableReader array, VariableReader index, VariableReader value) {
             DependencyNode valueNode = nodes[value.getIndex()];
             DependencyNode arrayNode = nodes[array.getIndex()];
-            valueNode.connect(arrayNode.getArrayItem());
+            if (valueNode != null && arrayNode != null) {
+                valueNode.connect(arrayNode.getArrayItem());
+            }
         }
 
         @Override
@@ -460,13 +513,20 @@ class DependencyGraphBuilder {
             methodDep.use();
             DependencyNode[] targetParams = methodDep.getVariables();
             for (int i = 0; i < arguments.size(); ++i) {
-                nodes[arguments.get(i).getIndex()].connect(targetParams[i + 1]);
+                DependencyNode value = nodes[arguments.get(i).getIndex()];
+                DependencyNode param = targetParams[i + 1];
+                if (value != null && param != null) {
+                    value.connect(param);
+                }
             }
             if (instance != null) {
                 nodes[instance.getIndex()].connect(targetParams[0]);
             }
             if (methodDep.getResult() != null && receiver != null) {
-                methodDep.getResult().connect(nodes[receiver.getIndex()]);
+                DependencyNode receiverNode = nodes[receiver.getIndex()];
+                if (methodDep.getResult() != null && receiverNode != null) {
+                    methodDep.getResult().connect(receiverNode);
+                }
             }
             methodDep.getThrown().addConsumer(currentExceptionConsumer);
             initClass(method.getClassName());
diff --git a/teavm-core/src/main/java/org/teavm/dependency/DependencyNode.java b/teavm-core/src/main/java/org/teavm/dependency/DependencyNode.java
index d5d4f8dbc..a4522c30b 100644
--- a/teavm-core/src/main/java/org/teavm/dependency/DependencyNode.java
+++ b/teavm-core/src/main/java/org/teavm/dependency/DependencyNode.java
@@ -23,19 +23,21 @@ import java.util.*;
  */
 public class DependencyNode implements ValueDependencyInfo {
     private DependencyChecker dependencyChecker;
-    private Set<DependencyConsumer> followers = new HashSet<>();
+    private List<DependencyConsumer> followers;
     private BitSet types;
-    private Map<DependencyNode, DependencyNodeToNodeTransition> transitions = new HashMap<>();
+    private List<DependencyNodeToNodeTransition> transitions;
     private volatile String tag;
     private DependencyNode arrayItemNode;
     private int degree;
+    int index;
 
-    DependencyNode(DependencyChecker dependencyChecker) {
-        this(dependencyChecker, 0);
+    DependencyNode(DependencyChecker dependencyChecker, int index) {
+        this(dependencyChecker, index, 0);
     }
 
-    DependencyNode(DependencyChecker dependencyChecker, int degree) {
+    DependencyNode(DependencyChecker dependencyChecker, int index, int degree) {
         this.dependencyChecker = dependencyChecker;
+        this.index = index;
         this.degree = degree;
     }
 
@@ -54,8 +56,10 @@ public class DependencyNode implements ValueDependencyInfo {
             if (DependencyChecker.shouldLog) {
                 System.out.println(tag + " -> " + type.getName());
             }
-            for (DependencyConsumer consumer : followers.toArray(new DependencyConsumer[followers.size()])) {
-                dependencyChecker.schedulePropagation(consumer, type);
+            if (followers != null) {
+                for (DependencyConsumer consumer : followers.toArray(new DependencyConsumer[followers.size()])) {
+                    dependencyChecker.schedulePropagation(consumer, type);
+                }
             }
         }
     }
@@ -81,13 +85,22 @@ public class DependencyNode implements ValueDependencyInfo {
                 System.out.println(tag + " -> " + types[i].getName());
             }
         }
-        for (DependencyConsumer consumer : followers.toArray(new DependencyConsumer[followers.size()])) {
-            dependencyChecker.schedulePropagation(consumer, Arrays.copyOf(types, j));
+        if (followers != null) {
+            for (DependencyConsumer consumer : followers.toArray(new DependencyConsumer[followers.size()])) {
+                dependencyChecker.schedulePropagation(consumer, Arrays.copyOf(types, j));
+            }
         }
     }
 
     public void addConsumer(DependencyConsumer consumer) {
-        if (followers.add(consumer) && this.types != null) {
+        if (followers == null) {
+            followers = new ArrayList<>();
+        }
+        if (followers.contains(consumer)) {
+            return;
+        }
+        followers.add(consumer);
+        if (this.types != null) {
             List<DependencyType> types = new ArrayList<>();
             for (int index = this.types.nextSetBit(0); index >= 0; index = this.types.nextSetBit(index + 1)) {
                 types.add(dependencyChecker.types.get(index));
@@ -100,14 +113,26 @@ public class DependencyNode implements ValueDependencyInfo {
         if (this == node) {
             return;
         }
-        DependencyNodeToNodeTransition transition = new DependencyNodeToNodeTransition(this, node, filter);
-        if (!transitions.containsKey(node)) {
-            transitions.put(node, transition);
-            if (DependencyChecker.shouldLog) {
-                System.out.println("Connecting " + tag + " to " + node.tag);
-            }
-            addConsumer(transition);
+        if (node == null) {
+            throw new IllegalArgumentException("Node must not be null");
         }
+        if (transitions != null) {
+            for (DependencyNodeToNodeTransition transition : transitions) {
+                if (transition.destination == node) {
+                    return;
+                }
+            }
+        }
+        DependencyNodeToNodeTransition transition = new DependencyNodeToNodeTransition(this, node, filter);
+        if (transitions == null) {
+            transitions = new ArrayList<>();
+        }
+
+        transitions.add(transition);
+        if (DependencyChecker.shouldLog) {
+            System.out.println("Connecting " + tag + " to " + node.tag);
+        }
+        addConsumer(transition);
     }
 
     public void connect(DependencyNode node) {
@@ -117,7 +142,8 @@ public class DependencyNode implements ValueDependencyInfo {
     @Override
     public DependencyNode getArrayItem() {
         if (arrayItemNode == null) {
-            arrayItemNode = new DependencyNode(dependencyChecker, degree + 1);
+            arrayItemNode = new DependencyNode(dependencyChecker, dependencyChecker.nodes.size(), degree + 1);
+            dependencyChecker.nodes.add(arrayItemNode);
             if (DependencyChecker.shouldLog) {
                 arrayItemNode.tag = tag + "[";
             }
diff --git a/teavm-core/src/main/java/org/teavm/dependency/DependencyNodeToNodeTransition.java b/teavm-core/src/main/java/org/teavm/dependency/DependencyNodeToNodeTransition.java
index 98543636e..e20b478cf 100644
--- a/teavm-core/src/main/java/org/teavm/dependency/DependencyNodeToNodeTransition.java
+++ b/teavm-core/src/main/java/org/teavm/dependency/DependencyNodeToNodeTransition.java
@@ -20,8 +20,8 @@ package org.teavm.dependency;
  * @author Alexey Andreev
  */
 class DependencyNodeToNodeTransition implements DependencyConsumer {
-    private DependencyNode source;
-    private DependencyNode destination;
+    DependencyNode source;
+    DependencyNode destination;
     private DependencyTypeFilter filter;
 
     public DependencyNodeToNodeTransition(DependencyNode source, DependencyNode destination,
diff --git a/teavm-core/src/main/java/org/teavm/model/InstructionReadVisitor.java b/teavm-core/src/main/java/org/teavm/model/InstructionReadVisitor.java
index 5d7627469..b5a8ff811 100644
--- a/teavm-core/src/main/java/org/teavm/model/InstructionReadVisitor.java
+++ b/teavm-core/src/main/java/org/teavm/model/InstructionReadVisitor.java
@@ -153,7 +153,7 @@ class InstructionReadVisitor implements InstructionVisitor {
 
     @Override
     public void visit(PutFieldInstruction insn) {
-        reader.putField(insn.getInstance(), insn.getField(), insn.getValue());
+        reader.putField(insn.getInstance(), insn.getField(), insn.getValue(), insn.getFieldType());
     }
 
     @Override
diff --git a/teavm-core/src/main/java/org/teavm/model/MethodReference.java b/teavm-core/src/main/java/org/teavm/model/MethodReference.java
index 66ab8a600..05092683c 100644
--- a/teavm-core/src/main/java/org/teavm/model/MethodReference.java
+++ b/teavm-core/src/main/java/org/teavm/model/MethodReference.java
@@ -99,6 +99,10 @@ public class MethodReference {
         return Arrays.copyOf(signature, signature.length);
     }
 
+    public ValueType getReturnType() {
+        return signature[signature.length - 1];
+    }
+
     public String getName() {
         return name;
     }
diff --git a/teavm-core/src/main/java/org/teavm/model/instructions/InstructionReader.java b/teavm-core/src/main/java/org/teavm/model/instructions/InstructionReader.java
index 2b022cf8b..afdea1647 100644
--- a/teavm-core/src/main/java/org/teavm/model/instructions/InstructionReader.java
+++ b/teavm-core/src/main/java/org/teavm/model/instructions/InstructionReader.java
@@ -79,7 +79,7 @@ public interface InstructionReader {
 
     void getField(VariableReader receiver, VariableReader instance, FieldReference field, ValueType fieldType);
 
-    void putField(VariableReader instance, FieldReference field, VariableReader value);
+    void putField(VariableReader instance, FieldReference field, VariableReader value, ValueType fieldType);
 
     void arrayLength(VariableReader receiver, VariableReader array);
 
@@ -100,8 +100,8 @@ public interface InstructionReader {
     void initClass(String className);
 
     void nullCheck(VariableReader receiver, VariableReader value);
-    
+
     void monitorEnter(VariableReader objectRef);
-    
+
     void monitorExit(VariableReader objectRef);
 }
diff --git a/teavm-core/src/main/java/org/teavm/model/instructions/PutFieldInstruction.java b/teavm-core/src/main/java/org/teavm/model/instructions/PutFieldInstruction.java
index 016217576..6308e284f 100644
--- a/teavm-core/src/main/java/org/teavm/model/instructions/PutFieldInstruction.java
+++ b/teavm-core/src/main/java/org/teavm/model/instructions/PutFieldInstruction.java
@@ -17,6 +17,7 @@ package org.teavm.model.instructions;
 
 import org.teavm.model.FieldReference;
 import org.teavm.model.Instruction;
+import org.teavm.model.ValueType;
 import org.teavm.model.Variable;
 
 /**
@@ -27,6 +28,7 @@ public class PutFieldInstruction extends Instruction {
     private Variable instance;
     private FieldReference field;
     private Variable value;
+    private ValueType fieldType;
 
     public Variable getInstance() {
         return instance;
@@ -52,6 +54,14 @@ public class PutFieldInstruction extends Instruction {
         this.value = value;
     }
 
+    public ValueType getFieldType() {
+        return fieldType;
+    }
+
+    public void setFieldType(ValueType fieldType) {
+        this.fieldType = fieldType;
+    }
+
     @Override
     public void acceptVisitor(InstructionVisitor visitor) {
         visitor.visit(this);
diff --git a/teavm-core/src/main/java/org/teavm/model/util/AsyncMethodFinder.java b/teavm-core/src/main/java/org/teavm/model/util/AsyncMethodFinder.java
index e882cbdf6..610b5ce6b 100644
--- a/teavm-core/src/main/java/org/teavm/model/util/AsyncMethodFinder.java
+++ b/teavm-core/src/main/java/org/teavm/model/util/AsyncMethodFinder.java
@@ -330,7 +330,8 @@ public class AsyncMethodFinder {
         }
 
         @Override
-        public void putField(VariableReader instance, FieldReference field, VariableReader value) {
+        public void putField(VariableReader instance, FieldReference field, VariableReader value,
+                ValueType fieldType) {
         }
 
         @Override
diff --git a/teavm-core/src/main/java/org/teavm/model/util/InstructionStringifier.java b/teavm-core/src/main/java/org/teavm/model/util/InstructionStringifier.java
index c3a2a1a54..812b354e7 100644
--- a/teavm-core/src/main/java/org/teavm/model/util/InstructionStringifier.java
+++ b/teavm-core/src/main/java/org/teavm/model/util/InstructionStringifier.java
@@ -280,7 +280,7 @@ public class InstructionStringifier implements InstructionReader {
     }
 
     @Override
-    public void putField(VariableReader instance, FieldReference field, VariableReader value) {
+    public void putField(VariableReader instance, FieldReference field, VariableReader value, ValueType fieldType) {
         if (instance != null) {
             sb.append("@").append(instance.getIndex());
         } else {
diff --git a/teavm-core/src/main/java/org/teavm/model/util/ProgramUtils.java b/teavm-core/src/main/java/org/teavm/model/util/ProgramUtils.java
index 4f5a2b80e..357bb68d1 100644
--- a/teavm-core/src/main/java/org/teavm/model/util/ProgramUtils.java
+++ b/teavm-core/src/main/java/org/teavm/model/util/ProgramUtils.java
@@ -398,11 +398,13 @@ public final class ProgramUtils {
         }
 
         @Override
-        public void putField(VariableReader instance, FieldReference field, VariableReader value) {
+        public void putField(VariableReader instance, FieldReference field, VariableReader value,
+                ValueType fieldType) {
             PutFieldInstruction insnCopy = new PutFieldInstruction();
             insnCopy.setField(field);
             insnCopy.setInstance(instance != null ? copyVar(instance) : null);
             insnCopy.setValue(copyVar(value));
+            insnCopy.setFieldType(fieldType);
             copy = insnCopy;
             copy.setLocation(location);
         }
diff --git a/teavm-core/src/main/java/org/teavm/parsing/ProgramParser.java b/teavm-core/src/main/java/org/teavm/parsing/ProgramParser.java
index 8a9f92ea4..a379c459a 100644
--- a/teavm-core/src/main/java/org/teavm/parsing/ProgramParser.java
+++ b/teavm-core/src/main/java/org/teavm/parsing/ProgramParser.java
@@ -1568,7 +1568,7 @@ public class ProgramParser implements VariableDebugInformation {
                     addInstruction(insn);
                     break;
                 }
-                    
+
             }
         }
 
@@ -1611,6 +1611,7 @@ public class ProgramParser implements VariableDebugInformation {
                     insn.setInstance(getVariable(instance));
                     insn.setField(new FieldReference(ownerCls, name));
                     insn.setValue(getVariable(value));
+                    insn.setFieldType(ValueType.parse(desc));
                     addInstruction(insn);
                     break;
                 }
diff --git a/teavm-core/src/main/java/org/teavm/tooling/ProgramSourceAggregator.java b/teavm-core/src/main/java/org/teavm/tooling/ProgramSourceAggregator.java
index 9dc33d3d6..c2e5fb3bc 100644
--- a/teavm-core/src/main/java/org/teavm/tooling/ProgramSourceAggregator.java
+++ b/teavm-core/src/main/java/org/teavm/tooling/ProgramSourceAggregator.java
@@ -77,7 +77,8 @@ class ProgramSourceAggregator implements InstructionReader {
     @Override public void create(VariableReader receiver, String type) { }
     @Override public void getField(VariableReader receiver, VariableReader instance, FieldReference field,
             ValueType fieldType) { }
-    @Override public void putField(VariableReader instance, FieldReference field, VariableReader value) { }
+    @Override public void putField(VariableReader instance, FieldReference field, VariableReader value,
+            ValueType fieldType) { }
     @Override public void arrayLength(VariableReader receiver, VariableReader array) { }
     @Override public void cloneArray(VariableReader receiver, VariableReader array) { }
     @Override public void unwrapArray(VariableReader receiver, VariableReader array, ArrayElementType elementType) { }
@@ -91,11 +92,11 @@ class ProgramSourceAggregator implements InstructionReader {
 
     @Override
     public void monitorEnter(VariableReader objectRef) {
-        
+
     }
 
     @Override
     public void monitorExit(VariableReader objectRef) {
-        
+
     }
 }