diff --git a/src/catch2/internal/catch_unreachable.cpp b/src/catch2/internal/catch_unreachable.cpp
new file mode 100644
index 0000000000..9f3af49e3a
--- /dev/null
+++ b/src/catch2/internal/catch_unreachable.cpp
@@ -0,0 +1,17 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#include <catch2/internal/catch_unreachable.hpp>
+
+namespace Catch {
+    namespace Detail {
+
+        void unreachable(){}
+
+    }
+} // end namespace Catch
diff --git a/src/catch2/internal/catch_unreachable.hpp b/src/catch2/internal/catch_unreachable.hpp
new file mode 100644
index 0000000000..297b8d6d67
--- /dev/null
+++ b/src/catch2/internal/catch_unreachable.hpp
@@ -0,0 +1,21 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+#ifndef CATCH_UNREACHABLE_HPP_INCLUDED
+#define CATCH_UNREACHABLE_HPP_INCLUDED
+
+namespace Catch {
+
+    namespace Detail {
+        // TODO: explain
+        [[noreturn]] void unreachable();
+
+    }
+
+} // end namespace Catch
+
+#endif // CATCH_UNREACHABLE_HPP_INCLUDED