diff --git a/test/todo/bug1139.c b/test/todo/bug1139.c
new file mode 100644
index 000000000..222a9ab51
--- /dev/null
+++ b/test/todo/bug1139.c
@@ -0,0 +1,52 @@
+/*
+  Copyright 2020 The cc65 Authors
+
+  This software is provided 'as-is', without any express or implied
+  warranty. In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+/*
+  Tests bit-field in if condition; see https://github.com/cc65/cc65/issues/1139
+*/
+
+#include <stdio.h>
+
+static unsigned char failures = 0;
+
+static struct overlap {
+    unsigned int x : 10;
+    unsigned int y : 10;
+} o = {11, 22};
+
+/* Test using bit-fields in if conditions. */
+static void test_if(void)
+{
+    o.x = 0;
+    o.y = 44;
+    if (o.x) {
+        printf("Bad, o.x is false\n");
+        failures++;
+    } else {
+        printf("Good\n");
+    }
+}
+
+int main(void)
+{
+    test_if();
+    printf("failures: %u\n", failures);
+    return failures;
+}