Make always not default constructible with primitive types

boostorg · Jun 26, 2016 · ddb7f22 · ddb7f22
1 parent d9917dd
commit ddb7f22
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Showing 2 changed files with 23 additions and 1 deletion.
diff --git a/include/fit/always.hpp b/include/fit/always.hpp
@@ -79,7 +79,7 @@
 
 namespace fit { namespace always_detail {
 
-template<class T>
+template<class T, class=void>
 struct always_base
 {
     T x;
@@ -94,6 +94,22 @@ struct always_base
     }
 };
 
+template<class T>
+struct always_base<T, typename std::enable_if<std::is_arithmetic<T>::value>::type>
+{
+    T x;
+
+    constexpr always_base(T xp) : x(xp)
+    {}
+
+    template<class... As>
+    constexpr typename detail::unwrap_reference<T>::type 
+    operator()(As&&...) const
+    {
+        return this->x;
+    }
+};
+
 #if FIT_NO_CONSTEXPR_VOID
 #define FIT_ALWAYS_VOID_RETURN fit::always_detail::always_base<void>::void_
 #else

diff --git a/test/always.cpp b/test/always.cpp
@@ -31,3 +31,9 @@ FIT_TEST_CASE()
     FIT_STATIC_TEST_CHECK(ten(1,2,3,4,5) == 10);
     FIT_TEST_CHECK(ten(1,2,3,4,5) == 10);
 }
+
+FIT_TEST_CASE()
+{
+    auto f = fit::always(10);
+    STATIC_ASSERT_NOT_DEFAULT_CONSTRUCTIBLE(decltype(f));
+}