Minor: reveal nullability problem in generateSyntheticParts()

compiler/backend/src/org/jetbrains/kotlin/codegen/AsmUtil.java

@@ -424,7 +424,7 @@ public class AsmUtil {
         v.athrow();
     }
 
-    public static void genClosureFields(CalculatedClosure closure, ClassBuilder v, KotlinTypeMapper typeMapper) {
+    public static void genClosureFields(@NotNull CalculatedClosure closure, ClassBuilder v, KotlinTypeMapper typeMapper) {
         List<Pair<String, Type>> allFields = new ArrayList<Pair<String, Type>>();
 
         ClassifierDescriptor captureThis = closure.getCaptureThis();

compiler/backend/src/org/jetbrains/kotlin/codegen/context/CodegenContext.java

@@ -47,7 +47,7 @@ public abstract class CodegenContext<T extends DeclarationDescriptor> {
     private final OwnerKind contextKind;
     private final CodegenContext parentContext;
     private final ClassDescriptor thisDescriptor;
-    public final MutableClosure closure;
+    @Nullable public final MutableClosure closure;
     private final LocalLookup enclosingLocalLookup;
     private final NullableLazyValue<StackValue.Field> outerExpression;