Resolve descriptors in error class objects

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

@@ -31,6 +31,8 @@ import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.BindingContext;
 import org.jetbrains.jet.lang.resolve.BindingTrace;
 import org.jetbrains.jet.lang.resolve.BindingTraceContext;
+import org.jetbrains.jet.lang.resolve.DescriptorUtils;
+import org.jetbrains.jet.lang.resolve.lazy.data.JetClassLikeInfo;
 import org.jetbrains.jet.lang.resolve.lazy.declarations.DeclarationProviderFactory;
 import org.jetbrains.jet.lang.resolve.lazy.declarations.PackageMemberDeclarationProvider;
 import org.jetbrains.jet.lang.resolve.lazy.descriptors.LazyClassDescriptor;
@@ -189,10 +191,35 @@ public class ResolveSession implements KotlinCodeAnalyzer {
     }
 
     /*package*/ LazyClassDescriptor getClassObjectDescriptor(JetClassObject classObject) {
-        LazyClassDescriptor classDescriptor = (LazyClassDescriptor) getClassDescriptor(PsiTreeUtil.getParentOfType(classObject, JetClass.class));
-        LazyClassDescriptor classObjectDescriptor = (LazyClassDescriptor) classDescriptor.getClassObjectDescriptor();
-        assert classObjectDescriptor != null : "Class object is declared, but is null for " + classDescriptor;
-        return classObjectDescriptor;
+        JetClass aClass = PsiTreeUtil.getParentOfType(classObject, JetClass.class);
+
+        LazyClassDescriptor parentClassDescriptor;
+
+        if (aClass != null) {
+            parentClassDescriptor = (LazyClassDescriptor) getClassDescriptor(aClass);
+        }
+        else {
+            // Class object in object is an error but we want to find descriptors even for this case
+            JetObjectDeclaration objectDeclaration = PsiTreeUtil.getParentOfType(classObject, JetObjectDeclaration.class);
+            assert objectDeclaration != null : String.format("Class object %s can be in class or object in file %s", classObject, classObject.getContainingFile().getText());
+            parentClassDescriptor = (LazyClassDescriptor) getClassDescriptor(objectDeclaration);
+        }
+
+        // Activate resolution and writing to trace
+        parentClassDescriptor.getClassObjectDescriptor();
+        DeclarationDescriptor declaration = getBindingContext().get(BindingContext.DECLARATION_TO_DESCRIPTOR, classObject.getObjectDeclaration());
+
+        if (declaration == null) {
+            // It's possible that there are several class objects and another class object is taking part in lazy resolve. We still want to
+            // build descriptors for such class objects.
+            JetClassLikeInfo classObjectInfo = parentClassDescriptor.getClassObjectInfo(classObject);
+            if (classObjectInfo != null) {
+                Name name = DescriptorUtils.getClassObjectName(parentClassDescriptor.getName().asString());
+                return new LazyClassDescriptor(this, parentClassDescriptor, name, classObjectInfo);
+            }
+        }
+
+        return (LazyClassDescriptor) declaration;
     }
 
     @Override

compiler/frontend/src/org/jetbrains/jet/lang/resolve/lazy/descriptors/LazyClassDescriptor.java

@@ -292,7 +292,7 @@ public class LazyClassDescriptor extends ClassDescriptorBase implements LazyDesc
     }
 
     @Nullable
-    private JetClassLikeInfo getClassObjectInfo(JetClassObject classObject) {
+    public JetClassLikeInfo getClassObjectInfo(JetClassObject classObject) {
         if (classObject != null) {
             if (!DescriptorUtils.inStaticContext(this)) {
                 return null;

idea/testData/resolve/references/InObjectClassObject.kt

@@ -0,0 +1,11 @@
+package test
+
+class A
+
+object b {
+    class object {
+        val x = <caret>A()
+    }
+}
+
+// REF: (test).A

idea/testData/resolve/references/InSecondClassObject.kt

@@ -0,0 +1,15 @@
+package test
+
+class A
+
+class Many {
+    class object {
+        val x = A()
+    }
+
+    class object {
+        val y = <caret>A()
+    }
+}
+
+// REF: (test).A

idea/tests/org/jetbrains/jet/resolve/ReferenceResolveTestGenerated.java

@@ -86,6 +86,16 @@ public class ReferenceResolveTestGenerated extends AbstractResolveBaseTest {
         doTest("idea/testData/resolve/references/InFunctionParameterType.kt");
     }
     
+    @TestMetadata("InObjectClassObject.kt")
+    public void testInObjectClassObject() throws Exception {
+        doTest("idea/testData/resolve/references/InObjectClassObject.kt");
+    }
+    
+    @TestMetadata("InSecondClassObject.kt")
+    public void testInSecondClassObject() throws Exception {
+        doTest("idea/testData/resolve/references/InSecondClassObject.kt");
+    }
+    
     @TestMetadata("PackageReference.kt")
     public void testPackageReference() throws Exception {
         doTest("idea/testData/resolve/references/PackageReference.kt");