Index: clang/lib/Driver/ToolChains/MSVC.cpp
===================================================================
--- clang/lib/Driver/ToolChains/MSVC.cpp
+++ clang/lib/Driver/ToolChains/MSVC.cpp
@@ -1266,9 +1266,8 @@
   if (MSVT.empty() &&
       Args.hasFlag(options::OPT_fms_extensions, options::OPT_fno_ms_extensions,
                    IsWindowsMSVC)) {
-    // -fms-compatibility-version=18.00 is default.
-    // FIXME: Consider bumping this to 19 (MSVC2015) soon.
-    MSVT = VersionTuple(18);
+    // -fms-compatibility-version=19.10 is default, aka 2017
+    MSVT = VersionTuple(19, 10);
   }
   return MSVT;
 }