putting a compare on stack as void type is a nop, not an error

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

@@ -235,8 +235,11 @@ public abstract class StackValue {
 
         @Override
         public void put(Type type, InstructionAdapter v) {
+            if (type == Type.VOID_TYPE) {
+                return;
+            }
             if (type != Type.BOOLEAN_TYPE) {
-                throw new UnsupportedOperationException("don't know how to put a compare as a non-boolean type");
+                throw new UnsupportedOperationException("don't know how to put a compare as a non-boolean type " + type);
             }
             putAsBoolean(v);
         }

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

@@ -408,4 +408,10 @@ public class NamespaceGenTest extends CodegenTestCase {
     public void testCheckCast() throws Exception {
         blackBoxFile("checkCast.jet");
     }
+
+    public void testPutBooleanAsVoid() throws Exception {
+        loadText("class C(val x: Int) { { x > 0 } } fun box() { val c = C(0) } ");
+        final Method main = generateFunction();
+        main.invoke(null);  // must not fail
+    }
 }