diff --git a/api/sixtyfps-cpp/include/sixtyfps_pathdata.h b/api/sixtyfps-cpp/include/sixtyfps_pathdata.h
index 41a30aeff..d618be772 100644
--- a/api/sixtyfps-cpp/include/sixtyfps_pathdata.h
+++ b/api/sixtyfps-cpp/include/sixtyfps_pathdata.h
@@ -48,6 +48,7 @@ public:
             case cbindgen_private::types::PathData::Tag::None:
                 return true;
         }
+        return false; //unreachable
     }
     friend bool operator!=(const PathData &a, const PathData &b) {
         return !(a == b);
diff --git a/tests/cases/simple.60 b/tests/cases/simple.60
index 174b7c7b4..5083bf3f5 100644
--- a/tests/cases/simple.60
+++ b/tests/cases/simple.60
@@ -13,8 +13,7 @@ TestCase := Rectangle {
 
 /*
 ```cpp
-auto handle = TestCase::create();
-const TestCase &instance = *handle;
+TestCase::create();
 ```
 
 ```rust
diff --git a/tests/driver/cppdriver.rs b/tests/driver/cppdriver.rs
index 3a650a9de..7f389b561 100644
--- a/tests/driver/cppdriver.rs
+++ b/tests/driver/cppdriver.rs
@@ -93,6 +93,7 @@ pub fn test(testcase: &test_driver_lib::TestCase) -> Result<(), Box<dyn Error>>
     if compiler.is_like_clang() || compiler.is_like_gnu() {
         compiler_command.arg("-std=c++17");
         compiler_command.arg("-g");
+        compiler_command.arg("-Werror").arg("-Wall").arg("-Wextra");
         compiler_command.arg(concat!("-L", env!("CPP_LIB_PATH")));
         compiler_command.arg("-lsixtyfps_rendering_backend_default");
         compiler_command.arg("-o").arg(&*binary_path);