diff --git a/tests/issues.cpp b/tests/issues.cpp
index 1cd8550..8636373 100644
--- a/tests/issues.cpp
+++ b/tests/issues.cpp
@@ -91,3 +91,13 @@ TEST_CASE("Issue 34", "[issues.34]") {
       .and_then (work2);
   result.map_error ([&] (std::string result) {errorhandling (result);});
 }
+
+struct non_copyable {
+	non_copyable(non_copyable&&) = default;
+	non_copyable(non_copyable const&) = delete;
+	non_copyable() = default;
+};
+
+TEST_CASE("Issue 42", "[issues.42]") {
+	tl::expected<non_copyable,int>{}.map([](non_copyable) {});
+}
\ No newline at end of file
diff --git a/tl/expected.hpp b/tl/expected.hpp
index 659d5d1..8e8bc6e 100644
--- a/tl/expected.hpp
+++ b/tl/expected.hpp
@@ -1301,7 +1301,7 @@ public:
   /// \synopsis template <class F> constexpr auto map(F &&f) &&;
   template <class F>
   TL_EXPECTED_11_CONSTEXPR decltype(
-      expected_map_impl(std::declval<expected &>(), std::declval<F &&>()))
+      expected_map_impl(std::declval<expected>(), std::declval<F &&>()))
   map(F &&f) && {
     return expected_map_impl(std::move(*this), std::forward<F>(f));
   }