Index: flang/include/flang/Common/idioms.h
===================================================================
--- flang/include/flang/Common/idioms.h
+++ flang/include/flang/Common/idioms.h
@@ -16,7 +16,7 @@
 #ifndef __cplusplus
 #error this is a C++ program
 #endif
-#if __cplusplus < 201703L
+#if __cplusplus < 201703L && !_MSC_VER
 #error this is a C++17 program
 #endif
 #if !__clang__ && defined __GNUC__ && __GNUC__ < 7