Cut throwOnFail

Summary:
[Folly] Cut `throwOnFail`.

It is not necessary, and `CHECK_THROW`, its reason for existing, can be implemented without it.

It can also easily be a pessimization because there is no way to delay computation of the arguments to the exception ctor until after the check. So if there is, say, a computation using `sformat` to compute a string argument to the exception ctor, that will always be performed rather than being performed only should the check fail.

Reviewed By: Orvid

Differential Revision: D5478804

fbshipit-source-id: 71a125c126eae76c6e95ef1bd23ee883b1db39a5

folly/Exception.h

@@ -103,18 +103,15 @@ void checkFopenErrorExplicit(FILE* fp, int savedErrno, Args&&... args) {
   }
 }
 
-template <typename E, typename V, typename... Args>
-void throwOnFail(V&& value, Args&&... args) {
-  if (!value) {
-    throw E(std::forward<Args>(args)...);
-  }
-}
-
 /**
  * If cond is not true, raise an exception of type E.  E must have a ctor that
  * works with const char* (a description of the failure).
  */
 #define CHECK_THROW(cond, E)           \
-  ::folly::throwOnFail<E>((cond), "Check failed: " #cond)
+  do {                                 \
+    if (!(cond)) {                     \
+      throw E("Check failed: " #cond); \
+    }                                  \
+  } while (0)
 
 }  // namespace folly