diff --git a/libcxx/include/vector b/libcxx/include/vector
--- a/libcxx/include/vector
+++ b/libcxx/include/vector
@@ -745,7 +745,7 @@
                                          const void *__new_mid) const
     {
 
-      if (!__libcpp_is_constant_evaluated() && __beg && is_same<allocator_type, __default_allocator_type>::value)
+      if (!__libcpp_is_constant_evaluated() && __beg)
         __sanitizer_annotate_contiguous_container(__beg, __end, __old_mid, __new_mid);
     }
 #else
diff --git a/libcxx/test/libcxx/containers/sequences/vector/asan.pass.cpp b/libcxx/test/libcxx/containers/sequences/vector/asan.pass.cpp
--- a/libcxx/test/libcxx/containers/sequences/vector/asan.pass.cpp
+++ b/libcxx/test/libcxx/containers/sequences/vector/asan.pass.cpp
@@ -36,7 +36,7 @@
         const T t[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
         C c(std::begin(t), std::end(t));
         c.reserve(2*c.size());
-        volatile T foo = c[c.size()];    // bad, but not caught by ASAN
+        volatile T foo = c[c.size() - 1];
         ((void)foo);
     }
 #endif