diff --git a/compiler/testData/codegen/regressions/kt528.kt b/compiler/testData/codegen/regressions/kt528.kt
new file mode 100644
index 00000000000..456f55d04be
--- /dev/null
+++ b/compiler/testData/codegen/regressions/kt528.kt
@@ -0,0 +1,118 @@
+namespace mask
+
+import std.io.*
+import java.io.*
+import java.util.*
+import java.util.Iterator as It
+import java.lang.Iterable as Itl
+
+fun box() : String {
+    val input = StringReader("/Users/abreslav/work/jet/docs/luhnybin/src/test")
+
+    val luhny = Luhny()
+    input.forEachChar {
+        luhny.charIn(it)
+    }
+    luhny.printAll()
+    return "OK"
+}
+
+class Luhny() {
+    val buffer = LinkedList<Char>()
+    val digits = LinkedList<Int>()
+
+    var toBeMasked = 0
+
+    fun charIn(it : Char) {
+        buffer.addLast(it)
+        when (it) {
+            .isDigit() => digits.addLast(it.int - '0'.int)
+            ' ', '-' => {}
+            else => {
+                    printAll()
+                    digits.clear()
+            }
+        }
+        if (digits.size() > 16)
+          printOneDigit()
+        check()
+    }
+
+    fun check() {
+        if (digits.size() < 14) return
+        print("check")
+        val sum = digits.sum { i, d =>
+//            println("$i -> $d")
+            if (i % 2 == digits.size()) {
+                val f = d * 2 / 10
+                val s = d * 2 % 10
+//                println("$d: f = $f, s = $s")
+                (f + s).pr {
+//                    println("to be doubled: $i -> $d : $it")
+                }
+            } else d
+        }
+//        println(sum)
+        if (sum % 10 == 0) {print("s"); toBeMasked = digits.size()}
+    }
+
+    fun printOneDigit() {
+        while (!buffer.isEmpty()) {
+            val c = buffer.removeFirst()
+            out(c)
+            if (c.isDigit()) {
+                digits.removeFirst()
+                return
+            }
+        }
+    }
+
+    fun printAll() {
+        while (!buffer.isEmpty())
+          out(buffer.removeFirst())
+    }
+
+    fun out(c : Char) {
+        if (toBeMasked > 0) {
+            print('X')
+            toBeMasked--
+        }
+        else {
+            print(c)
+        }
+    }
+}
+
+fun <T> T.pr(f : fun(T) : Unit) : T {
+    f(this)
+    return this
+}
+
+fun LinkedList<Int>.sum(f : fun(Int, Int ): Int): Int {
+    var sum = 0
+    for (i in 1..size()) {
+        val j = size() - i
+        sum += f(j, get(j))
+    }
+    return sum
+}
+
+//fun <T> List<T>.backwards() : Itl<T> = object : Itl<T> {
+//  override fun iterator() : It<T> =
+//      object : It<T> {
+//          var current = size()
+//          override fun next() : T = get(--current)
+//          override fun hasNext() : Boolean = current > 0
+//          override fun remove() {throw UnsupportedOperationException()}
+//      }
+//}
+
+fun Char.isDigit() = Character.isDigit(this)
+
+fun Reader.forEachChar(body : fun(Char) : Unit) {
+    do {
+        var i = read();
+        if (i == -1) break
+        body(i.chr)
+    } while(true)
+}
\ No newline at end of file
diff --git a/compiler/tests/org/jetbrains/jet/codegen/StdlibTest.java b/compiler/tests/org/jetbrains/jet/codegen/StdlibTest.java
index 86a7f1d1e31..fdfbbecfa5b 100644
--- a/compiler/tests/org/jetbrains/jet/codegen/StdlibTest.java
+++ b/compiler/tests/org/jetbrains/jet/codegen/StdlibTest.java
@@ -81,4 +81,8 @@ public class StdlibTest extends CodegenTestCase {
     public void testKt529 () {
         blackBoxFile("regressions/kt529.kt");
     }
+
+    public void testKt528 () {
+        blackBoxFile("regressions/kt528.kt");
+    }
 }