use do-while-false in FOLLY_SAFE_CHECK

Summary: To avoid the marginal but still unnecessary compile-time cost of constructing a lambda. And enclose the full thing in braces so it can be used in an unbraced `if`.

Reviewed By: ot, luciang

Differential Revision: D27817005

fbshipit-source-id: 9a1a6e0389fea5907a3a20cffbd6a029b0a85eb9

folly/lang/SafeAssert.h

@@ -31,24 +31,25 @@
 #define FOLLY_DETAIL_SAFE_CHECK_LINKAGE static
 #endif
 
-#define FOLLY_DETAIL_SAFE_CHECK_IMPL(d, p, expr, expr_s, ...)                  \
-  if ((!d || ::folly::kIsDebug || ::folly::kIsSanitize) &&                     \
-      !static_cast<bool>(expr)) {                                              \
-    FOLLY_DETAIL_SAFE_CHECK_LINKAGE constexpr auto                             \
-        __folly_detail_safe_assert_fun = __PRETTY_FUNCTION__;                  \
-    FOLLY_DETAIL_SAFE_CHECK_LINKAGE constexpr ::folly::detail::safe_assert_arg \
-        __folly_detail_safe_assert_arg{                                        \
-            FOLLY_PP_STRINGIZE(expr_s),                                        \
-            __FILE__,                                                          \
-            __LINE__,                                                          \
-            __folly_detail_safe_assert_fun,                                    \
-            ::folly::detail::safe_assert_msg_types<decltype(                   \
-                ::folly::detail::safe_assert_msg_types_seq_of(                 \
-                    __VA_ARGS__))>::value.data};                               \
-    ::folly::detail::safe_assert_terminate<p>(                                 \
-        __folly_detail_safe_assert_arg, __VA_ARGS__);                          \
-  }                                                                            \
-  [] {}()
+#define FOLLY_DETAIL_SAFE_CHECK_IMPL(d, p, expr, expr_s, ...)     \
+  do {                                                            \
+    if ((!d || ::folly::kIsDebug || ::folly::kIsSanitize) &&      \
+        !static_cast<bool>(expr)) {                               \
+      FOLLY_DETAIL_SAFE_CHECK_LINKAGE constexpr auto              \
+          __folly_detail_safe_assert_fun = __PRETTY_FUNCTION__;   \
+      FOLLY_DETAIL_SAFE_CHECK_LINKAGE constexpr ::folly::detail:: \
+          safe_assert_arg __folly_detail_safe_assert_arg{         \
+              FOLLY_PP_STRINGIZE(expr_s),                         \
+              __FILE__,                                           \
+              __LINE__,                                           \
+              __folly_detail_safe_assert_fun,                     \
+              ::folly::detail::safe_assert_msg_types<decltype(    \
+                  ::folly::detail::safe_assert_msg_types_seq_of(  \
+                      __VA_ARGS__))>::value.data};                \
+      ::folly::detail::safe_assert_terminate<p>(                  \
+          __folly_detail_safe_assert_arg, __VA_ARGS__);           \
+    }                                                             \
+  } while (false)
 
 //  FOLLY_SAFE_CHECK
 //