correctly generate supertypes of class objects and object literals

idea/src/org/jetbrains/jet/codegen/ImplementationBodyCodegen.java

@@ -34,6 +34,9 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
         if (!(myClass instanceof JetObjectDeclaration)) {
             interfaces.add(JetTypeMapper.jvmNameForInterface(descriptor));
         }
+        else {
+            interfaces.addAll(InterfaceBodyCodegen.getSuperInterfaces(myClass, state.getBindingContext()));
+        }
 
         boolean isAbstract = myClass instanceof JetClass && ((JetClass) myClass).hasModifier(JetTokens.ABSTRACT_KEYWORD);
 
@@ -59,6 +62,10 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
         if (first instanceof JetDelegatorToSuperClass || first instanceof JetDelegatorToSuperCall) {
             JetType superType = state.getBindingContext().resolveTypeReference(first.getTypeReference());
             ClassDescriptor superClassDescriptor = (ClassDescriptor) superType.getConstructor().getDeclarationDescriptor();
+            final PsiElement declaration = state.getBindingContext().getDeclarationPsiElement(superClassDescriptor);
+            if (declaration instanceof PsiClass && ((PsiClass) declaration).isInterface()) {
+                return "java/lang/Object";
+            }
             return state.getTypeMapper().jvmName(superClassDescriptor, kind);
         }
 

idea/src/org/jetbrains/jet/codegen/InterfaceBodyCodegen.java

@@ -5,6 +5,7 @@ import com.intellij.psi.PsiElement;
 import org.jetbrains.jet.lang.descriptors.ClassDescriptor;
 import org.jetbrains.jet.lang.psi.JetClassOrObject;
 import org.jetbrains.jet.lang.psi.JetDelegationSpecifier;
+import org.jetbrains.jet.lang.resolve.BindingContext;
 import org.jetbrains.jet.lang.types.JetType;
 import org.objectweb.asm.ClassVisitor;
 import org.objectweb.asm.Opcodes;
@@ -23,7 +24,7 @@ public class InterfaceBodyCodegen extends ClassBodyCodegen {
     }
 
     protected void generateDeclaration() {
-        Set<String> superInterfaces = getSuperInterfaces();
+        Set<String> superInterfaces = getSuperInterfaces(myClass, state.getBindingContext());
 
         String fqName = JetTypeMapper.jvmNameForInterface(descriptor);
         v.visit(Opcodes.V1_6,
@@ -35,20 +36,20 @@ public class InterfaceBodyCodegen extends ClassBodyCodegen {
         );
     }
 
-    private Set<String> getSuperInterfaces() {
-        List<JetDelegationSpecifier> delegationSpecifiers = myClass.getDelegationSpecifiers();
+    static Set<String> getSuperInterfaces(JetClassOrObject aClass, final BindingContext bindingContext) {
+        List<JetDelegationSpecifier> delegationSpecifiers = aClass.getDelegationSpecifiers();
         String superClassName = null;
         Set<String> superInterfaces = new LinkedHashSet<String>();
         for (JetDelegationSpecifier specifier : delegationSpecifiers) {
-            JetType superType = state.getBindingContext().resolveTypeReference(specifier.getTypeReference());
+            JetType superType = bindingContext.resolveTypeReference(specifier.getTypeReference());
             ClassDescriptor superClassDescriptor = (ClassDescriptor) superType.getConstructor().getDeclarationDescriptor();
-            PsiElement superPsi = state.getBindingContext().getDeclarationPsiElement(superClassDescriptor);
+            PsiElement superPsi = bindingContext.getDeclarationPsiElement(superClassDescriptor);
 
             if (superPsi instanceof PsiClass) {
                 PsiClass psiClass = (PsiClass) superPsi;
                 String fqn = psiClass.getQualifiedName();
                 if (psiClass.isInterface()) {
-                    superInterfaces.add(fqn);
+                    superInterfaces.add(fqn.replace('.', '/'));
                 }
                 else {
                     if (superClassName == null) {

idea/testData/codegen/classes/classObjectInterface.jet

@@ -0,0 +1,9 @@
+class C() {
+  fun getInstance(): Runnable = C
+
+  class object: Runnable {
+    fun run(): Unit { }
+  }
+}
+
+fun foo() = C().getInstance()

idea/tests/org/jetbrains/jet/codegen/ClassGenTest.java

@@ -123,4 +123,11 @@ public class ClassGenTest extends CodegenTestCase {
     public void testClassObjectMethod() throws Exception {
         blackBoxFile("classes/classObjectMethod.jet");
     }
+
+    public void testClassObjectInterface() throws Exception {
+        loadFile("classes/classObjectInterface.jet");
+        final Method method = generateFunction();
+        Object result = method.invoke(null);
+        assertInstanceOf(result, Runnable.class);
+    }
 }