JS backend: detect outer class if used in child local fun.

Fix closure fields when use it from nested functions in method.

(cherry picked from commit 20eea36)

js/js.translator/src/org/jetbrains/k2js/translate/context/UsageTracker.java

@@ -34,8 +34,6 @@ public final class UsageTracker {
     @NotNull
     private final MemberDescriptor memberDescriptor;
 
-    @Nullable
-    private final UsageTracker parent;
     @Nullable
     private List<UsageTracker> children;
 
@@ -47,7 +45,6 @@ public final class UsageTracker {
     public UsageTracker(@NotNull MemberDescriptor memberDescriptor, @Nullable UsageTracker parent, @Nullable ClassDescriptor trackedClassDescriptor) {
         this.memberDescriptor = memberDescriptor;
         this.trackedClassDescriptor = trackedClassDescriptor;
-        this.parent = parent;
         if (parent != null) {
             parent.addChild(this);
         }
@@ -119,16 +116,18 @@ public final class UsageTracker {
 
     @Nullable
     public ClassDescriptor getOuterClassDescriptor() {
-        if (outerClassDescriptor == null && parent != null) {
-            UsageTracker p = parent;
-            do {
-                if (p.outerClassDescriptor != null) {
-                    return p.outerClassDescriptor;
-                }
-            }
-            while ((p = p.parent) != null);
+        if (outerClassDescriptor != null || children == null) {
+            return outerClassDescriptor;
         }
-        return outerClassDescriptor;
+
+        for (UsageTracker child : children) {
+            ClassDescriptor childOuterClassDescriptor = child.getOuterClassDescriptor();
+            if (childOuterClassDescriptor != null) {
+                return childOuterClassDescriptor;
+            }
+        }
+
+        return null;
     }
 
     public void forEachCaptured(Consumer<CallableDescriptor> consumer) {

js/js.translator/src/org/jetbrains/k2js/translate/expression/LiteralFunctionTranslator.java

@@ -116,7 +116,9 @@ public class LiteralFunctionTranslator {
         if (asInner) {
             addRegularParameters(descriptor, fun, funContext, receiverName);
             if (outerClass != null) {
-                if (funContext.usageTracker().isUsed()) {
+                UsageTracker usageTracker = funContext.usageTracker();
+                assert usageTracker != null;
+                if (usageTracker.isUsed()) {
                     return new JsInvocation(rootContext.namer().kotlin("assignOwner"), fun, JsLiteral.THIS);
                 }
                 else {
@@ -159,15 +161,15 @@ public class LiteralFunctionTranslator {
             @NotNull ClassTranslator classTranslator) {
         JsFunction fun = createFunction();
         JsNameRef outerClassRef = fun.getScope().declareName("$this").makeRef();
-        TranslationContext funContext = rootContext
-                .contextWithScope(fun, rootContext.aliasingContext().inner(outerClass, outerClassRef), new UsageTracker(descriptor, null,
-                                                                                                                        outerClass));
+        UsageTracker usageTracker = new UsageTracker(descriptor, null, outerClass);
+        TranslationContext funContext = rootContext.contextWithScope(fun, rootContext.aliasingContext().inner(outerClass, outerClassRef),
+                                                                     usageTracker);
 
         fun.getBody().getStatements().add(new JsReturn(classTranslator.translate(funContext)));
         JetClassBody body = declaration.getBody();
         assert body != null;
         InnerObjectTranslator translator = new InnerObjectTranslator(funContext, fun);
-        return translator.translate(createReference(fun), funContext.usageTracker().isUsed() ? outerClassRef : null);
+        return translator.translate(createReference(fun), usageTracker.isUsed() ? outerClassRef : null);
     }
 }