diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/TypeParameterDescriptor.java b/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/TypeParameterDescriptor.java
index dd01df6d884..939104ff740 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/TypeParameterDescriptor.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/descriptors/TypeParameterDescriptor.java
@@ -73,7 +73,7 @@ public class TypeParameterDescriptor extends DeclarationDescriptorImpl implement
                 this,
                 annotations,
                 false,
-                "&" + name,
+                name,
                 Collections.<TypeParameterDescriptor>emptyList(),
                 upperBounds);
     }
diff --git a/idea/src/org/jetbrains/jet/plugin/codeInsight/OverrideImplementMethodsHandler.java b/idea/src/org/jetbrains/jet/plugin/codeInsight/OverrideImplementMethodsHandler.java
index f3c8838cae5..55299ca3379 100644
--- a/idea/src/org/jetbrains/jet/plugin/codeInsight/OverrideImplementMethodsHandler.java
+++ b/idea/src/org/jetbrains/jet/plugin/codeInsight/OverrideImplementMethodsHandler.java
@@ -104,12 +104,15 @@ public abstract class OverrideImplementMethodsHandler implements LanguageCodeIns
         if (!returnType.equals(stdlib.getTuple0Type())) {
             bodyBuilder.append(": ").append(returnType.toString());
         }
-        bodyBuilder.append("{");
+
         final String initializer = defaultInitializer(returnType, stdlib);
         if (initializer != null) {
-            bodyBuilder.append("return " ).append(initializer);
+            bodyBuilder.append(" = ").append(initializer);
         }
-        bodyBuilder.append("}");
+        else {
+            bodyBuilder.append("{").append("throw UnsupportedOperationException()").append("}");
+        }
+
         return JetPsiFactory.createFunction(project, bodyBuilder.toString());
     }
 
diff --git a/idea/testData/codeInsight/overrideImplement/genericMethod.kt.after b/idea/testData/codeInsight/overrideImplement/genericMethod.kt.after
index f55e765fc4e..8ec50fce31e 100644
--- a/idea/testData/codeInsight/overrideImplement/genericMethod.kt.after
+++ b/idea/testData/codeInsight/overrideImplement/genericMethod.kt.after
@@ -4,7 +4,5 @@ trait G<T> {
 
 class GC() : G<Int> {
 
-    override fun foo(t: Int): Int {
-        return 0
-    }
+    override fun foo(t: Int): Int = 0
 }
diff --git a/idea/testData/codeInsight/overrideImplement/javaInterfaceMethod/foo/Impl.kt.after b/idea/testData/codeInsight/overrideImplement/javaInterfaceMethod/foo/Impl.kt.after
index f0e3fb14e49..6554a1fc9fb 100644
--- a/idea/testData/codeInsight/overrideImplement/javaInterfaceMethod/foo/Impl.kt.after
+++ b/idea/testData/codeInsight/overrideImplement/javaInterfaceMethod/foo/Impl.kt.after
@@ -2,7 +2,5 @@ import foo.Intf
 
 class Impl(): Intf {
 
-    override fun getFooBar(): String? {
-        return null
-    }
+    override fun getFooBar(): String? = null
 }
diff --git a/idea/testData/codeInsight/overrideImplement/javaParameters/foo/Impl.kt.after b/idea/testData/codeInsight/overrideImplement/javaParameters/foo/Impl.kt.after
index a20e435f471..da4335ee7f9 100644
--- a/idea/testData/codeInsight/overrideImplement/javaParameters/foo/Impl.kt.after
+++ b/idea/testData/codeInsight/overrideImplement/javaParameters/foo/Impl.kt.after
@@ -3,5 +3,6 @@ import foo.Intf
 class Impl(): Intf {
 
     override fun fooBar(i: Int, s: Array<String?>?, foo: Any?) {
+        throw UnsupportedOperationException()
     }
 }
diff --git a/idea/testData/codeInsight/overrideImplement/traitGenericOverride.kt b/idea/testData/codeInsight/overrideImplement/traitGenericOverride.kt
new file mode 100644
index 00000000000..b2387d42ad4
--- /dev/null
+++ b/idea/testData/codeInsight/overrideImplement/traitGenericOverride.kt
@@ -0,0 +1,7 @@
+trait G<T> {
+    fun foo(t : T) : T
+}
+
+class GC<T>() : G<T> {
+    <caret>
+}
\ No newline at end of file
diff --git a/idea/testData/codeInsight/overrideImplement/traitGenericOverride.kt.after b/idea/testData/codeInsight/overrideImplement/traitGenericOverride.kt.after
new file mode 100644
index 00000000000..4ef321e0344
--- /dev/null
+++ b/idea/testData/codeInsight/overrideImplement/traitGenericOverride.kt.after
@@ -0,0 +1,10 @@
+trait G<T> {
+    fun foo(t : T) : T
+}
+
+class GC<T>() : G<T> {
+
+    override fun foo(t: T): T {
+        throw UnsupportedOperationException()
+    }
+}
\ No newline at end of file
diff --git a/idea/testData/codeInsight/overrideImplement/traitNullableFunction.kt b/idea/testData/codeInsight/overrideImplement/traitNullableFunction.kt
new file mode 100644
index 00000000000..e1dcebe7663
--- /dev/null
+++ b/idea/testData/codeInsight/overrideImplement/traitNullableFunction.kt
@@ -0,0 +1,7 @@
+trait Some {
+    fun foo(some : Int?) : Int
+}
+
+class SomeOther : Some {
+    <caret>
+}
\ No newline at end of file
diff --git a/idea/testData/codeInsight/overrideImplement/traitNullableFunction.kt.after b/idea/testData/codeInsight/overrideImplement/traitNullableFunction.kt.after
new file mode 100644
index 00000000000..5ad1f152481
--- /dev/null
+++ b/idea/testData/codeInsight/overrideImplement/traitNullableFunction.kt.after
@@ -0,0 +1,8 @@
+trait Some {
+    fun foo(some : Int?) : Int
+}
+
+class SomeOther : Some {
+
+    override fun foo(some: Int?): Int = 0
+}
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/jet/plugin/codeInsight/OverrideImplementTest.java b/idea/tests/org/jetbrains/jet/plugin/codeInsight/OverrideImplementTest.java
index 8d528827964..42d1948e86e 100644
--- a/idea/tests/org/jetbrains/jet/plugin/codeInsight/OverrideImplementTest.java
+++ b/idea/tests/org/jetbrains/jet/plugin/codeInsight/OverrideImplementTest.java
@@ -46,6 +46,14 @@ public class OverrideImplementTest extends LightCodeInsightFixtureTestCase {
         doFileTest();
     }
 
+    public void testTraitGenericOverride() {
+        doFileTest();
+    }
+
+    public void testTraitNullableFunction() {
+        doFileTest();
+    }
+
     private void doFileTest() {
         myFixture.configureByFile(getTestName(true) + ".kt");
         doImplement();