diff --git a/compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java b/compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
index 050bd7da483..a5ef0c787f7 100644
--- a/compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
+++ b/compiler/backend/src/org/jetbrains/jet/codegen/ExpressionCodegen.java
@@ -1307,6 +1307,9 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> {
                 else if(type.getSort() == Type.DOUBLE) {
                     v.aconst(0d);
                 }
+                else if(type.getSort() == Type.LONG) {
+                    v.aconst(0l);
+                }
                 else {
                     v.iconst(0);
                 }
diff --git a/compiler/tests/org/jetbrains/jet/codegen/PrimitiveTypesTest.java b/compiler/tests/org/jetbrains/jet/codegen/PrimitiveTypesTest.java
index d52a2e3c488..033f9c56b68 100644
--- a/compiler/tests/org/jetbrains/jet/codegen/PrimitiveTypesTest.java
+++ b/compiler/tests/org/jetbrains/jet/codegen/PrimitiveTypesTest.java
@@ -284,4 +284,21 @@ public class PrimitiveTypesTest extends CodegenTestCase {
     public void testKt518 () throws Exception {
         blackBoxFile("regressions/kt518.jet");
     }
+
+    public void testKt665() throws Exception {
+        loadText("fun f(x: Long, zzz: Long = 1): Long\n" +
+                 "{\n" +
+                 "    return if (x <= 1) zzz\n" +
+                 "    else f(x-1, x*zzz)\n" +
+                 "}\n" +
+                 "\n" +
+                 "fun box() : String\n" +
+                 "{\n" +
+                 "    val six: Long = 6;\n" +
+                 "    System.out?.println(f(six))\n" +
+                 "    return \"OK\"" +
+                 "}");
+        System.out.println(generateToText());
+        blackBox();
+    }
 }