diff --git a/idea/src/org/jetbrains/jet/lang/resolve/BindingContext.java b/idea/src/org/jetbrains/jet/lang/resolve/BindingContext.java
index 0a77c8d3ecd..422766542db 100644
--- a/idea/src/org/jetbrains/jet/lang/resolve/BindingContext.java
+++ b/idea/src/org/jetbrains/jet/lang/resolve/BindingContext.java
@@ -41,6 +41,8 @@ public interface BindingContext {
     boolean isStatement(JetExpression expression);
     boolean hasBackingField(PropertyDescriptor propertyDescriptor);
 
+    boolean isVariableReassignment(JetBinaryExpression expression);
+
     ConstructorDescriptor resolveSuperConstructor(JetDelegatorToSuperCall superCall);
 
     @Nullable
diff --git a/idea/src/org/jetbrains/jet/lang/resolve/BindingTrace.java b/idea/src/org/jetbrains/jet/lang/resolve/BindingTrace.java
index 13daaf37c58..b88c66bfdf5 100644
--- a/idea/src/org/jetbrains/jet/lang/resolve/BindingTrace.java
+++ b/idea/src/org/jetbrains/jet/lang/resolve/BindingTrace.java
@@ -29,6 +29,8 @@ public interface BindingTrace {
 
     void recordStatement(@NotNull JetElement statement);
 
+    void recordVariableReassignment(@NotNull JetBinaryExpression expression);
+
     void recordResolutionScope(@NotNull JetExpression expression, @NotNull JetScope scope);
 
     void removeStatementRecord(@NotNull JetElement statement);
diff --git a/idea/src/org/jetbrains/jet/lang/resolve/BindingTraceAdapter.java b/idea/src/org/jetbrains/jet/lang/resolve/BindingTraceAdapter.java
index 57357d72412..a57438f4775 100644
--- a/idea/src/org/jetbrains/jet/lang/resolve/BindingTraceAdapter.java
+++ b/idea/src/org/jetbrains/jet/lang/resolve/BindingTraceAdapter.java
@@ -57,6 +57,11 @@ public class BindingTraceAdapter implements BindingTrace {
         originalTrace.recordStatement(statement);
     }
 
+    @Override
+    public void recordVariableReassignment(@NotNull JetBinaryExpression expression) {
+        originalTrace.recordVariableReassignment(expression);
+    }
+
     @Override
     public void requireBackingField(@NotNull PropertyDescriptor propertyDescriptor) {
         originalTrace.requireBackingField(propertyDescriptor);
diff --git a/idea/src/org/jetbrains/jet/lang/resolve/BindingTraceContext.java b/idea/src/org/jetbrains/jet/lang/resolve/BindingTraceContext.java
index 51da91851ee..4534a9faf2a 100644
--- a/idea/src/org/jetbrains/jet/lang/resolve/BindingTraceContext.java
+++ b/idea/src/org/jetbrains/jet/lang/resolve/BindingTraceContext.java
@@ -31,6 +31,8 @@ public class BindingTraceContext implements BindingContext, BindingTrace {
     private final Map<JetExpression, JetType> autoCasts = Maps.newHashMap();
     private final Map<JetExpression, JetScope> resolutionScopes = Maps.newHashMap();
 
+    private final Set<JetBinaryExpression> variableReassignments = Sets.newHashSet();
+
     private final Set<JetFunctionLiteralExpression> blocks = new HashSet<JetFunctionLiteralExpression>();
     private final Set<JetElement> statements = new HashSet<JetElement>();
     private final Set<PropertyDescriptor> backingFieldRequired = new HashSet<PropertyDescriptor>();
@@ -61,6 +63,8 @@ public class BindingTraceContext implements BindingContext, BindingTrace {
         backingFieldRequired.addAll(other.backingFieldRequired);
         processed.addAll(other.processed);
 
+        variableReassignments.addAll(other.variableReassignments);
+
         diagnostics.addAll(other.diagnostics);
     }
 
@@ -158,6 +162,11 @@ public class BindingTraceContext implements BindingContext, BindingTrace {
         statements.add(statement);
     }
 
+    @Override
+    public void recordVariableReassignment(@NotNull JetBinaryExpression expression) {
+        variableReassignments.add(expression);
+    }
+
     @Override
     public void recordResolutionScope(@NotNull JetExpression expression, @NotNull JetScope scope) {
         safePut(resolutionScopes, expression, scope);
@@ -298,6 +307,11 @@ public class BindingTraceContext implements BindingContext, BindingTrace {
         return backingFieldRequired.contains(propertyDescriptor);
     }
 
+    @Override
+    public boolean isVariableReassignment(JetBinaryExpression expression) {
+        return variableReassignments.contains(expression);
+    }
+
     public ConstructorDescriptor resolveSuperConstructor(JetDelegatorToSuperCall superCall) {
         JetTypeReference typeReference = superCall.getTypeReference();
         if (typeReference == null) return null;
diff --git a/idea/src/org/jetbrains/jet/lang/types/JetTypeInferrer.java b/idea/src/org/jetbrains/jet/lang/types/JetTypeInferrer.java
index afe32649cc5..ceca8318ead 100644
--- a/idea/src/org/jetbrains/jet/lang/types/JetTypeInferrer.java
+++ b/idea/src/org/jetbrains/jet/lang/types/JetTypeInferrer.java
@@ -2587,7 +2587,10 @@ public class JetTypeInferrer {
 
             if (assignmentOperationType == null) {
                 String counterpartName = binaryOperationNames.get(assignmentOperationCounterparts.get(operationType));
-                getTypeForBinaryCall(expression, counterpartName, scope, true);
+                JetType typeForBinaryCall = getTypeForBinaryCall(expression, counterpartName, scope, true);
+                if (typeForBinaryCall != null) {
+                    context.trace.recordVariableReassignment(expression);
+                }
             }
             result = null; // not an expression
         }
diff --git a/idea/tests/org/jetbrains/jet/JetTestUtils.java b/idea/tests/org/jetbrains/jet/JetTestUtils.java
index d5285d1f87a..b6270e3bc80 100644
--- a/idea/tests/org/jetbrains/jet/JetTestUtils.java
+++ b/idea/tests/org/jetbrains/jet/JetTestUtils.java
@@ -53,6 +53,11 @@ public class JetTestUtils {
         public void recordStatement(@NotNull JetElement statement) {
         }
 
+        @Override
+        public void recordVariableReassignment(@NotNull JetBinaryExpression expression) {
+
+        }
+
         @Override
         public void recordResolutionScope(@NotNull JetExpression expression, @NotNull JetScope scope) {
         }
@@ -185,6 +190,11 @@ public class JetTestUtils {
                     throw new UnsupportedOperationException(); // TODO
                 }
 
+                @Override
+                public boolean isVariableReassignment(JetBinaryExpression expression) {
+                    throw new UnsupportedOperationException(); // TODO
+                }
+
                 @Override
                 public ConstructorDescriptor resolveSuperConstructor(JetDelegatorToSuperCall superCall) {
                     throw new UnsupportedOperationException(); // TODO