Fix codegen of loaded class objects

Remove useless check and todo.

 #KT-2717 Fixed
 #KT-3142 Fixed

compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java

@@ -1449,16 +1449,9 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> implem
         }
 
         if (descriptor instanceof ClassDescriptor) {
-            PsiElement declaration = descriptorToDeclaration(bindingContext, descriptor);
-            if (declaration instanceof JetClass) {
-                final ClassDescriptor classObjectDescriptor = ((ClassDescriptor) descriptor).getClassObjectDescriptor();
-                assert classObjectDescriptor != null;
-                return StackValue.singleton(classObjectDescriptor, typeMapper);
-            }
-            else {
-                // todo ?
-                return StackValue.none();
-            }
+            ClassDescriptor classObjectDescriptor = ((ClassDescriptor) descriptor).getClassObjectDescriptor();
+            assert classObjectDescriptor != null : "Class object is not found for " + descriptor;
+            return StackValue.singleton(classObjectDescriptor, typeMapper);
         }
 
         if (descriptor instanceof TypeParameterDescriptor) {

compiler/testData/compileKotlinAgainstKotlin/ClassObjectMember.A.kt

@@ -0,0 +1,6 @@
+class A {
+    class object {
+        fun foo() = 42
+        val bar = "OK"
+    }
+}

compiler/testData/compileKotlinAgainstKotlin/ClassObjectMember.B.kt

@@ -0,0 +1,4 @@
+fun main(args: Array<String>) {
+    if (A.foo() != 42) throw Exception()
+    if (A.bar != "OK") throw Exception()
+}

compiler/tests/org/jetbrains/jet/jvm/compiler/CompileKotlinAgainstKotlinTestGenerated.java

@@ -33,6 +33,11 @@ public class CompileKotlinAgainstKotlinTestGenerated extends AbstractCompileKotl
         JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), "org.jetbrains.jet.generators.tests.GenerateTests", new File("compiler/testData/compileKotlinAgainstKotlin"), "A.kt", true);
     }
     
+    @TestMetadata("ClassObjectMember.A.kt")
+    public void testClassObjectMember_A() throws Exception {
+        doTest("compiler/testData/compileKotlinAgainstKotlin/ClassObjectMember.A.kt");
+    }
+    
     @TestMetadata("DefaultConstructor.A.kt")
     public void testDefaultConstructor_A() throws Exception {
         doTest("compiler/testData/compileKotlinAgainstKotlin/DefaultConstructor.A.kt");