Update charconv.cc
diff --git a/absl/strings/charconv.cc b/absl/strings/charconv.cc
index 37d6f9f..db2b392 100644
--- a/absl/strings/charconv.cc
+++ b/absl/strings/charconv.cc
@@ -347,7 +347,7 @@
     } else {
       ptrdiff_t nan_size = input.subrange_end - input.subrange_begin;
       nan_size = std::min(nan_size, kNanBufferSize - 1);
-      std::copy_n(input.subrange_begin, nan_size, n_char_sequence);
+      std::copy_n(input.subrange_begin, nan_size, const_cast<char *>(n_char_sequence));
       n_char_sequence[nan_size] = '\0';
     }
     char* nan_argument = const_cast<char*>(n_char_sequence);