fix: check to make sure both 'if constexpr' and return type deduction…

… are available
fmtlib · Oct 13, 2021 · 6f65384 · 6f65384
1 parent dcd282b
commit 6f65384
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/include/fmt/compile.h b/include/fmt/compile.h
@@ -179,7 +179,7 @@ const T& first(const T& value, const Tail&...) {
   return value;
 }
 
-#ifdef __cpp_if_constexpr
+#if defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 template <typename... Args> struct type_list {};
 
 // Returns a reference to the argument at index N from [first, rest...].
@@ -530,7 +530,7 @@ constexpr auto compile(S format_str) {
     return result;
   }
 }
-#endif  // __cpp_if_constexpr
+#endif  // defined(__cpp_if_constexpr) && defined(__cpp_return_type_deduction)
 }  // namespace detail
 
 FMT_MODULE_EXPORT_BEGIN