fix for KT-245

idea/src/org/jetbrains/jet/codegen/ExpressionCodegen.java

@@ -263,7 +263,7 @@ public class ExpressionCodegen extends JetVisitor<StackValue, StackValue> {
         final JetParameter loopParameter = expression.getLoopParameter();
         final VariableDescriptor parameterDescriptor = bindingContext.get(BindingContext.VALUE_PARAMETER, loopParameter);
         JetType paramType = parameterDescriptor.getOutType();
-        Type asmParamType = typeMapper.mapType(paramType);
+        Type asmParamType = typeMapper.boxType(typeMapper.mapType(paramType));
 
         int iteratorVar = myMap.enterTemp();
         gen(expression.getLoopRange(), loopRangeType);

idea/testData/codegen/regressions/kt245.jet

@@ -0,0 +1,32 @@
+fun foo() {
+    val l = java.util.ArrayList<Int>(2)
+    l.add(1)
+
+    for (el in l) {}
+
+    //verify error "Expecting to find integer on stack"
+    val iterator = l.iterator()
+
+    //another verify error "Mismatched stack types"
+    while (iterator?.hasNext() ?: false) {
+        val i = iterator?.next()
+    }
+
+    //the same
+    if (iterator != null) {
+        while (iterator.hasNext()) {
+            val i = iterator?.next()
+        }
+    }
+
+    //this way it works
+    if (iterator != null) {
+        while (iterator.hasNext()) {
+            iterator.next() //because of the bug KT-244 i can't write "val i = iterator.next()"
+        }
+    }
+}
+
+fun box() : String {
+    return "OK"
+}

idea/tests/org/jetbrains/jet/codegen/Kt247Test.java

@@ -1,7 +0,0 @@
-package org.jetbrains.jet.codegen;
-
-public class Kt247Test extends CodegenTestCase {
-    public void testMe () throws Exception {
-        blackBoxFile("regressions/kt247.jet");
-    }
-}

idea/tests/org/jetbrains/jet/codegen/SafeRefTest.java

@@ -0,0 +1,11 @@
+package org.jetbrains.jet.codegen;
+
+public class SafeRefTest extends CodegenTestCase {
+    public void test247 () throws Exception {
+        blackBoxFile("regressions/kt247.jet");
+    }
+
+    public void test245 () throws Exception {
+        blackBoxFile("regressions/kt245.jet");
+    }
+}