diff --git a/lib/Support/Windows/TimeValue.inc b/lib/Support/Windows/TimeValue.inc
index 0223ab42448..b90b4f1da00 100644
--- a/lib/Support/Windows/TimeValue.inc
+++ b/lib/Support/Windows/TimeValue.inc
@@ -47,6 +47,7 @@ std::string TimeValue::str() const {
   __time64_t OurTime = this->toEpochTime();
   int Error = ::_localtime64_s(&Storage, &OurTime);
   assert(!Error);
+  (void)Error;
   LT = &Storage;
 #endif