From 249493264a9c1deba647a1656ed436c6e3745ad6 Mon Sep 17 00:00:00 2001
From: Alexander Lanin <alex@lanin.de>
Date: Mon, 14 Jun 2021 23:02:08 +0200
Subject: [PATCH] Improve error message for const fields

---
 include/nlohmann/json.hpp        | 1 +
 single_include/nlohmann/json.hpp | 1 +
 2 files changed, 2 insertions(+)

diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index 0bbaa9503a..d11a51d524 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -3236,6 +3236,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     ValueType & get_to(ValueType& v) const noexcept(noexcept(
                 JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t&>(), v)))
     {
+        static_assert(!std::is_const<ValueType>::value, "Cannot deserialize into constant fields");
         JSONSerializer<ValueType>::from_json(*this, v);
         return v;
     }
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 2716e1e7b3..0447d793a9 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -20256,6 +20256,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     ValueType & get_to(ValueType& v) const noexcept(noexcept(
                 JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t&>(), v)))
     {
+        static_assert(!std::is_const<ValueType>::value, "Cannot deserialize into constant fields");
         JSONSerializer<ValueType>::from_json(*this, v);
         return v;
     }