Auto-reserve any base of random access iterator

Summary:
Rather than demanding precisely a random access iterator, allow any base of it.

https://en.cppreference.com/w/cpp/iterator/iterator_tags

Reviewed By: yfeldblum, Gownta

Differential Revision: D33039206

fbshipit-source-id: 7b62c03704a70340a605df4d7885dce29726d8ee

folly/container/F14Map.h

@@ -329,9 +329,9 @@ class F14BasicMap {
     // is easy to disable at a particular call site by asking for an
     // initialCapacity of 1.
     bool autoReserve =
-        std::is_same<
-            typename std::iterator_traits<InputIt>::iterator_category,
-            std::random_access_iterator_tag>::value &&
+        std::is_base_of<
+            std::random_access_iterator_tag,
+            typename std::iterator_traits<InputIt>::iterator_category>::value &&
         initialCapacity == 0;
     bulkInsert(first, last, autoReserve);
   }
@@ -343,9 +343,9 @@ class F14BasicMap {
     // ourself to situations that mimic bulk construction without an
     // explicit initialCapacity.
     bool autoReserve =
-        std::is_same<
-            typename std::iterator_traits<InputIt>::iterator_category,
-            std::random_access_iterator_tag>::value &&
+        std::is_base_of<
+            std::random_access_iterator_tag,
+            typename std::iterator_traits<InputIt>::iterator_category>::value &&
         bucket_count() == 0;
     bulkInsert(first, last, autoReserve);
   }

folly/container/F14Set.h

@@ -285,9 +285,9 @@ class F14BasicSet {
     // is easy to disable at a particular call site by asking for an
     // initialCapacity of 1.
     bool autoReserve =
-        std::is_same<
-            typename std::iterator_traits<InputIt>::iterator_category,
-            std::random_access_iterator_tag>::value &&
+        std::is_base_of<
+            std::random_access_iterator_tag,
+            typename std::iterator_traits<InputIt>::iterator_category>::value &&
         initialCapacity == 0;
     bulkInsert(first, last, autoReserve);
   }
@@ -299,9 +299,9 @@ class F14BasicSet {
     // ourself to situations that mimic bulk construction without an
     // explicit initialCapacity.
     bool autoReserve =
-        std::is_same<
-            typename std::iterator_traits<InputIt>::iterator_category,
-            std::random_access_iterator_tag>::value &&
+        std::is_base_of<
+            std::random_access_iterator_tag,
+            typename std::iterator_traits<InputIt>::iterator_category>::value &&
         bucket_count() == 0;
     bulkInsert(first, last, autoReserve);
   }