diff --git a/compiler/testData/codegen/box/classes/kt3001.kt b/compiler/testData/codegen/box/classes/kt3001.kt
new file mode 100644
index 00000000000..35925eade05
--- /dev/null
+++ b/compiler/testData/codegen/box/classes/kt3001.kt
@@ -0,0 +1,11 @@
+trait A {
+    val result: String
+}
+
+class Base(override val result: String) : A
+
+open class Derived : A by Base("OK")
+
+class Z : Derived()
+
+fun box() = Z().result
diff --git a/compiler/testData/codegen/box/classes/kt3414.kt b/compiler/testData/codegen/box/classes/kt3414.kt
new file mode 100644
index 00000000000..6770d466086
--- /dev/null
+++ b/compiler/testData/codegen/box/classes/kt3414.kt
@@ -0,0 +1,18 @@
+trait A {
+    fun foo(): Int
+}
+
+trait B {
+    fun foo(): Int
+}
+
+class Z(val a: A) : A by a, B
+
+fun box(): String {
+    val s = Z(object : A {
+        override fun foo(): Int {
+            return 1;
+        }
+    });
+    return if (s.foo() == 1) "OK" else "fail"
+}
\ No newline at end of file
diff --git a/compiler/testData/codegen/boxWithStdlib/regressions/kt1770.kt b/compiler/testData/codegen/boxWithStdlib/regressions/kt1770.kt
new file mode 100644
index 00000000000..db7ca78eb28
--- /dev/null
+++ b/compiler/testData/codegen/boxWithStdlib/regressions/kt1770.kt
@@ -0,0 +1,17 @@
+import org.w3c.dom.Element
+import org.xml.sax.InputSource
+import javax.xml.parsers.DocumentBuilderFactory
+import java.io.StringReader
+
+class MyElement(e: Element): Element by e {
+    fun bar() = "OK"
+}
+
+fun box() : String {
+    val factory = DocumentBuilderFactory.newInstance()!!;
+    val builder = factory.newDocumentBuilder()!!;
+    val source = InputSource(StringReader("<OK></OK>"));
+    val doc = builder.parse(source)!!;
+    val myElement = MyElement(doc.getDocumentElement()!!)
+    return myElement.getTagName()!!
+}
\ No newline at end of file
diff --git a/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxCodegenTestGenerated.java b/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxCodegenTestGenerated.java
index 240dbad08db..544069b7f3a 100644
--- a/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxCodegenTestGenerated.java
+++ b/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxCodegenTestGenerated.java
@@ -960,11 +960,21 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest("compiler/testData/codegen/box/classes/kt285.kt");
         }
         
+        @TestMetadata("kt3001.kt")
+        public void testKt3001() throws Exception {
+            doTest("compiler/testData/codegen/box/classes/kt3001.kt");
+        }
+        
         @TestMetadata("kt3114.kt")
         public void testKt3114() throws Exception {
             doTest("compiler/testData/codegen/box/classes/kt3114.kt");
         }
         
+        @TestMetadata("kt3414.kt")
+        public void testKt3414() throws Exception {
+            doTest("compiler/testData/codegen/box/classes/kt3414.kt");
+        }
+        
         @TestMetadata("kt343.kt")
         public void testKt343() throws Exception {
             doTest("compiler/testData/codegen/box/classes/kt343.kt");
diff --git a/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxWithStdlibCodegenTestGenerated.java b/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxWithStdlibCodegenTestGenerated.java
index 6543439e5eb..96533c05d3e 100644
--- a/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxWithStdlibCodegenTestGenerated.java
+++ b/compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxWithStdlibCodegenTestGenerated.java
@@ -654,6 +654,11 @@ public class BlackBoxWithStdlibCodegenTestGenerated extends AbstractBlackBoxCode
             doTestWithStdlib("compiler/testData/codegen/boxWithStdlib/regressions/kt1733.kt");
         }
         
+        @TestMetadata("kt1770.kt")
+        public void testKt1770() throws Exception {
+            doTestWithStdlib("compiler/testData/codegen/boxWithStdlib/regressions/kt1770.kt");
+        }
+        
         @TestMetadata("kt1779.kt")
         public void testKt1779() throws Exception {
             doTestWithStdlib("compiler/testData/codegen/boxWithStdlib/regressions/kt1779.kt");