coerce condition value to Type.BOOLEAN (KT-2147)

compiler/backend/src/org/jetbrains/jet/codegen/StackValue.java

@@ -72,8 +72,8 @@ public abstract class StackValue {
     }
 
     public void condJump(Label label, boolean jumpIfFalse, InstructionAdapter v) {
-        if (this.type == Type.BOOLEAN_TYPE) {
-            put(Type.BOOLEAN_TYPE, v);
+        put(this.type, v);
+        coerce(Type.BOOLEAN_TYPE, v);
         if (jumpIfFalse) {
             v.ifeq(label);
         }
@@ -81,10 +81,6 @@ public abstract class StackValue {
             v.ifne(label);
         }
     }
-        else {
-            throw new UnsupportedOperationException("can't generate a cond jump for a non-boolean value");
-        }
-    }
 
     public static StackValue local(int index, Type type) {
         return new Local(index, type);

compiler/testData/codegen/regressions/kt2147.kt

+class Foo {
+  fun isOk() = true
+}
+
+fun box(): String {
+   val foo: Foo? = Foo()
+   if (foo?.isOk()!!) return "OK"
+   return "fail"
+}

compiler/tests/org/jetbrains/jet/codegen/ControlStructuresTest.java

@@ -331,4 +331,9 @@ public class ControlStructuresTest extends CodegenTestCase {
         createEnvironmentWithMockJdkAndIdeaAnnotations(CompilerSpecialMode.JDK_HEADERS);
         blackBoxFile("regressions/kt1441.kt");
     }
+
+    public void testKt2147() throws Exception {
+        createEnvironmentWithMockJdkAndIdeaAnnotations(CompilerSpecialMode.JDK_HEADERS);
+        blackBoxFile("regressions/kt2147.kt");
+    }
 }