diff --git a/glm/detail/setup.hpp b/glm/detail/setup.hpp
index bde13ba0..56e6591a 100644
--- a/glm/detail/setup.hpp
+++ b/glm/detail/setup.hpp
@@ -299,7 +299,7 @@
 #	define GLM_HAS_IF_CONSTEXPR __has_feature(cxx_if_constexpr)
 # elif (GLM_COMPILER & GLM_COMPILER_GCC) 
 #	define GLM_HAS_IF_CONSTEXPR GLM_COMPILER >= GLM_COMPILER_GCC7
-# elif GLM_LANG_CXX17_FLAG
+# elif (GLM_LANG & GLM_LANG_CXX17_FLAG)
 # 	define GLM_HAS_IF_CONSTEXPR 1
 # else
 # 	define GLM_HAS_IF_CONSTEXPR 0