diff --git a/idea/src/org/jetbrains/jet/lang/annotations/JetPsiChecker.java b/idea/src/org/jetbrains/jet/lang/annotations/JetPsiChecker.java
index 4df270d6376..49740db4b1d 100644
--- a/idea/src/org/jetbrains/jet/lang/annotations/JetPsiChecker.java
+++ b/idea/src/org/jetbrains/jet/lang/annotations/JetPsiChecker.java
@@ -1,8 +1,10 @@
 package org.jetbrains.jet.lang.annotations;
 
+import com.intellij.codeInspection.ProblemHighlightType;
 import com.intellij.lang.ASTNode;
 import com.intellij.lang.annotation.AnnotationHolder;
 import com.intellij.lang.annotation.Annotator;
+import com.intellij.openapi.progress.ProcessCanceledException;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.TextRange;
 import com.intellij.psi.PsiElement;
@@ -28,7 +30,7 @@ public class JetPsiChecker implements Annotator {
                 final BindingContext bindingContext = AnalyzingUtils.analyzeFile(file, new ErrorHandler() {
                     @Override
                     public void unresolvedReference(JetReferenceExpression referenceExpression) {
-                        holder.createErrorAnnotation(referenceExpression, "Unresolved");
+                        holder.createErrorAnnotation(referenceExpression, "Unresolved").setHighlightType(ProblemHighlightType.LIKE_UNKNOWN_SYMBOL);
                     }
 
                     @Override
@@ -59,6 +61,9 @@ public class JetPsiChecker implements Annotator {
                     }
                 });
             }
+            catch (ProcessCanceledException e) {
+                // Canceled. We are fine
+            }
             catch (Throwable e) {
                 // TODO
                 holder.createErrorAnnotation(new TextRange(0, 1), e.getClass().getCanonicalName() + ": " + e.getMessage());
diff --git a/idea/src/org/jetbrains/jet/lang/resolve/TypeResolver.java b/idea/src/org/jetbrains/jet/lang/resolve/TypeResolver.java
index 401b2de46f8..4464143bf11 100644
--- a/idea/src/org/jetbrains/jet/lang/resolve/TypeResolver.java
+++ b/idea/src/org/jetbrains/jet/lang/resolve/TypeResolver.java
@@ -34,6 +34,7 @@ public class TypeResolver {
         return type;
     }
 
+    @NotNull
     private Type resolveTypeElement(final JetScope scope, final List<Attribute> attributes, JetTypeElement typeElement, final boolean nullable) {
         final Type[] result = new Type[1];
         if (typeElement != null) {
diff --git a/idea/src/org/jetbrains/jet/lang/types/JetTypeChecker.java b/idea/src/org/jetbrains/jet/lang/types/JetTypeChecker.java
index fab2ac4b3fe..fca21a33970 100644
--- a/idea/src/org/jetbrains/jet/lang/types/JetTypeChecker.java
+++ b/idea/src/org/jetbrains/jet/lang/types/JetTypeChecker.java
@@ -1,5 +1,6 @@
 package org.jetbrains.jet.lang.types;
 
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.jet.lang.psi.JetExpression;
 
@@ -293,7 +294,7 @@ public class JetTypeChecker {
         return false;
     }
 
-    public boolean isSubtypeOf(Type subtype, Type supertype) {
+    public boolean isSubtypeOf(@NotNull Type subtype, @NotNull Type supertype) {
         if (!supertype.isNullable() && subtype.isNullable()) {
             return false;
         }
diff --git a/idea/src/org/jetbrains/jet/lang/types/JetTypeInferrer.java b/idea/src/org/jetbrains/jet/lang/types/JetTypeInferrer.java
index 2815e4223ff..2d2d7ca169e 100644
--- a/idea/src/org/jetbrains/jet/lang/types/JetTypeInferrer.java
+++ b/idea/src/org/jetbrains/jet/lang/types/JetTypeInferrer.java
@@ -170,7 +170,7 @@ public class JetTypeInferrer {
                 if (expression.getOperationReference().getReferencedNameElementType() == JetTokens.COLON) {
                     Type actualType = getType(scope, expression.getLeft(), false);
                     Type expectedType = typeResolver.resolveType(scope, expression.getRight());
-                    if (!semanticServices.getTypeChecker().isSubtypeOf(actualType, expectedType)) {
+                    if (actualType != null && !semanticServices.getTypeChecker().isSubtypeOf(actualType, expectedType)) {
                         // TODO
                         semanticServices.getErrorHandler().typeMismatch(expression.getLeft(), expectedType, actualType);
                     }
@@ -350,11 +350,53 @@ public class JetTypeInferrer {
                 }
                 else if (operationType == JetTokens.PLUS) {
                     result[0] = getTypeForBinaryCall(expression, "plus", scope);
+                }
+                else if (operationType == JetTokens.EQ) {
+                    JetExpression left = expression.getLeft();
+                    if (left instanceof JetArrayAccessExpression) {
+                        JetArrayAccessExpression arrayAccessExpression = (JetArrayAccessExpression) left;
+                        resolveArrayAccessToLValue(arrayAccessExpression, expression.getRight(), expression.getOperationReference());
+                    }
+                    else {
+                        throw new UnsupportedOperationException();
+                    }
+                    result[0] = null; // TODO : This is not an expression, in fact!
                 } else {
                     throw new UnsupportedOperationException(); // TODO
                 }
             }
 
+            @Override
+            public void visitArrayAccessExpression(JetArrayAccessExpression expression) {
+                JetExpression arrayExpression = expression.getArrayExpression();
+                Type receiverType = getType(scope, arrayExpression, false);
+                List<JetExpression> indexExpressions = expression.getIndexExpressions();
+                List<Type> argumentTypes = getTypes(scope, indexExpressions);
+                if (argumentTypes == null) return;
+
+                // TODO : record unresolved
+                FunctionDescriptor functionDescriptor = lookupFunction(scope, null, "get", receiverType, argumentTypes);
+                if (functionDescriptor != null) {
+                    result[0] = functionDescriptor.getUnsubstitutedReturnType();
+                }
+            }
+
+            private void resolveArrayAccessToLValue(JetArrayAccessExpression arrayAccessExpression, JetExpression rightHandSide, JetReferenceExpression operationSign) {
+                List<Type> argumentTypes = getTypes(scope, arrayAccessExpression.getIndexExpressions());
+                if (argumentTypes == null) return;
+                Type rhsType = getType(scope, rightHandSide, false);
+                if (rhsType == null) return;
+                argumentTypes.add(rhsType);
+
+                Type receiverType = getType(scope, arrayAccessExpression.getArrayExpression(), false);
+                if (receiverType == null) return;
+
+                FunctionDescriptor functionDescriptor = lookupFunction(scope, operationSign, "set", receiverType, argumentTypes);
+                if (functionDescriptor != null) {
+                    result[0] = functionDescriptor.getUnsubstitutedReturnType();
+                }
+            }
+
             @Override
             public void visitJetElement(JetElement elem) {
                 throw new IllegalArgumentException("Unsupported element: " + elem);
@@ -369,9 +411,7 @@ public class JetTypeInferrer {
                     return ErrorType.createErrorType("No right argument");
                 }
                 Type rightType = getType(scope, right, false);
-                OverloadDomain overloadDomain = semanticServices.getOverloadResolver().getOverloadDomain(leftType, scope, name);
-                overloadDomain = wrapForTracing(overloadDomain, operationSign);
-                FunctionDescriptor functionDescriptor = overloadDomain.getFunctionDescriptorForPositionedArguments(Collections.<Type>emptyList(), Collections.singletonList(rightType));
+                FunctionDescriptor functionDescriptor = lookupFunction(scope, operationSign, name, leftType, Collections.singletonList(rightType));
                 if (functionDescriptor != null) {
                     return functionDescriptor.getUnsubstitutedReturnType();
                 }
@@ -384,6 +424,26 @@ public class JetTypeInferrer {
         return result[0];
     }
 
+    @Nullable
+    private FunctionDescriptor lookupFunction(JetScope scope, JetReferenceExpression reference, String name, Type receiverType, List<Type> argumentTypes) {
+        OverloadDomain overloadDomain = semanticServices.getOverloadResolver().getOverloadDomain(receiverType, scope, name);
+        overloadDomain = wrapForTracing(overloadDomain, reference);
+        return overloadDomain.getFunctionDescriptorForPositionedArguments(Collections.<Type>emptyList(), argumentTypes);
+    }
+
+    @Nullable
+    private List<Type> getTypes(JetScope scope, List<JetExpression> indexExpressions) {
+        List<Type> argumentTypes = new ArrayList<Type>();
+        for (JetExpression indexExpression : indexExpressions) {
+            Type type = getType(scope, indexExpression, false);
+            if (type == null) {
+                return null;
+            }
+            argumentTypes.add(type);
+        }
+        return argumentTypes;
+    }
+
 
     private OverloadDomain getOverloadDomain(final JetScope scope, JetExpression calleeExpression) {
         final OverloadDomain[] result = new OverloadDomain[1];
@@ -440,7 +500,7 @@ public class JetTypeInferrer {
         return wrapForTracing(result[0], reference[0]);
     }
 
-    private OverloadDomain wrapForTracing(final OverloadDomain overloadDomain, final JetReferenceExpression referenceExpression) {
+    private OverloadDomain wrapForTracing(final OverloadDomain overloadDomain, @Nullable final JetReferenceExpression referenceExpression) {
         if (overloadDomain == null) return OverloadDomain.EMPTY;
         return new OverloadDomain() {
             @Override
@@ -458,9 +518,13 @@ public class JetTypeInferrer {
             public FunctionDescriptor getFunctionDescriptorForPositionedArguments(@NotNull List<Type> typeArguments, @NotNull List<Type> positionedValueArgumentTypes) {
                 FunctionDescriptor descriptor = overloadDomain.getFunctionDescriptorForPositionedArguments(typeArguments, positionedValueArgumentTypes);
                 if (descriptor != null) {
-                    trace.recordReferenceResolution(referenceExpression, descriptor);
+                    if (referenceExpression != null) {
+                        trace.recordReferenceResolution(referenceExpression, descriptor);
+                    }
                 } else {
-                    semanticServices.getErrorHandler().unresolvedReference(referenceExpression);
+                    if (referenceExpression != null) {
+                        semanticServices.getErrorHandler().unresolvedReference(referenceExpression);
+                    }
                 }
                 return descriptor;
             }
@@ -476,7 +540,9 @@ public class JetTypeInferrer {
                 // TODO: consider other declarations
                 if (statement instanceof JetProperty) {
                     JetProperty property = (JetProperty) statement;
-                    scope.addPropertyDescriptor(classDescriptorResolver.resolvePropertyDescriptor(scope, property));
+                    PropertyDescriptor propertyDescriptor = classDescriptorResolver.resolvePropertyDescriptor(scope, property);
+                    scope.addPropertyDescriptor(propertyDescriptor);
+                    trace.recordDeclarationResolution(property, propertyDescriptor);
                 }
                 else if (statement instanceof JetExpression) {
                     getType(scope, (JetExpression) statement, true);