diff --git a/libcxx/include/__assert b/libcxx/include/__assert
--- a/libcxx/include/__assert
+++ b/libcxx/include/__assert
@@ -37,7 +37,7 @@
     (__builtin_expect(static_cast<bool>(expression), 1)                                                                \
          ? (void)0                                                                                                     \
          : _LIBCPP_VERBOSE_ABORT(                                                                                      \
-               "%s:%d: assertion %s failed: %s", __builtin_FILE(), __builtin_LINE(), #expression, message))
+               "%s:%d: assertion %s failed: %s\n", __builtin_FILE(), __builtin_LINE(), #expression, message))
 #elif !defined(_LIBCPP_ASSERTIONS_DISABLE_ASSUME) && __has_builtin(__builtin_assume)
 #  define _LIBCPP_ASSERT(expression, message)                                                                          \
     (_LIBCPP_DIAGNOSTIC_PUSH _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wassume")                                              \