Minor. Made method @NotNull.

compiler/frontend/src/org/jetbrains/jet/lang/resolve/BindingContext.java

@@ -44,6 +44,7 @@ import static org.jetbrains.jet.util.slicedmap.RewritePolicy.DO_NOTHING;
 
 public interface BindingContext {
     BindingContext EMPTY = new BindingContext() {
+        @NotNull
         @Override
         public Collection<Diagnostic> getDiagnostics() {
             return Collections.emptyList();
@@ -263,6 +264,7 @@ public interface BindingContext {
     @Deprecated // This field is needed only for the side effects of its initializer
             Void _static_initializer = BasicWritableSlice.initSliceDebugNames(BindingContext.class);
 
+    @NotNull
     Collection<Diagnostic> getDiagnostics();
 
     @Nullable

compiler/frontend/src/org/jetbrains/jet/lang/resolve/BindingTraceContext.java

@@ -37,6 +37,7 @@ public class BindingTraceContext implements BindingTrace {
 
     private final BindingContext bindingContext = new BindingContext() {
 
+        @NotNull
         @Override
         public Collection<Diagnostic> getDiagnostics() {
             return diagnostics;

compiler/frontend/src/org/jetbrains/jet/lang/resolve/DelegatingBindingTrace.java

@@ -38,6 +38,7 @@ public class DelegatingBindingTrace implements BindingTrace {
     private final String name;
 
     private final BindingContext bindingContext = new BindingContext() {
+        @NotNull
         @Override
         public Collection<Diagnostic> getDiagnostics() {
             ArrayList<Diagnostic> mergedDiagnostics = new ArrayList<Diagnostic>(diagnostics);

compiler/frontend/src/org/jetbrains/jet/lang/resolve/TraceUtil.java

@@ -62,6 +62,7 @@ public class TraceUtil {
     };
 
     public final static BindingContext BINDING_CONTEXT_STUB = new BindingContext() {
+        @NotNull
         @Override
         public Collection<Diagnostic> getDiagnostics() {
             throw new IllegalStateException();

compiler/frontend/src/org/jetbrains/jet/lang/resolve/lazy/storage/LockBasedStorageManager.java

@@ -238,6 +238,7 @@ public class LockBasedStorageManager implements StorageManager {
             this.context = context;
         }
 
+        @NotNull
         @Override
         public Collection<Diagnostic> getDiagnostics() {
             synchronized (lock) {

compiler/tests/org/jetbrains/jet/JetTestUtils.java

@@ -103,6 +103,7 @@ public class JetTestUtils {
         public BindingContext getBindingContext() {
             return new BindingContext() {
 
+                @NotNull
                 @Override
                 public Collection<Diagnostic> getDiagnostics() {
                     throw new UnsupportedOperationException(); // TODO
@@ -161,6 +162,7 @@ public class JetTestUtils {
         @Override
         public BindingContext getBindingContext() {
             return new BindingContext() {
+                @NotNull
                 @Override
                 public Collection<Diagnostic> getDiagnostics() {
                     throw new UnsupportedOperationException();