diff --git a/include/nlohmann/detail/input/lexer.hpp b/include/nlohmann/detail/input/lexer.hpp
index 9809b4e89..f516dd7a2 100644
--- a/include/nlohmann/detail/input/lexer.hpp
+++ b/include/nlohmann/detail/input/lexer.hpp
@@ -1250,7 +1250,7 @@ scan_number_done:
             if (errno == 0)
             {
                 value_unsigned = static_cast<number_unsigned_t>(x);
-                if (static_cast<typeof(x)>(value_unsigned) == x)
+                if (static_cast<decltype(x)>(value_unsigned) == x)
                 {
                     return token_type::value_unsigned;
                 }
@@ -1266,7 +1266,7 @@ scan_number_done:
             if (errno == 0)
             {
                 value_integer = static_cast<number_integer_t>(x);
-                if (static_cast<typeof(x)>(value_integer) == x)
+                if (static_cast<decltype(x)>(value_integer) == x)
                 {
                     return token_type::value_integer;
                 }
diff --git a/tests/src/unit-custom-integer.cpp b/tests/src/unit-custom-integer.cpp
index bcf6fa398..9de1fda02 100644
--- a/tests/src/unit-custom-integer.cpp
+++ b/tests/src/unit-custom-integer.cpp
@@ -86,11 +86,11 @@ template<typename T> class std::numeric_limits<wrapped_int<T>>
 
 TEST_CASE("custom integer types")
 {
-    using json = nlohmann::basic_json <
-                 std::map, std::vector, std::string, bool,
-                 wrapped_int<std::int64_t>, wrapped_int<std::uint64_t>, double, std::allocator >;
+    using my_json = nlohmann::basic_json <
+                    std::map, std::vector, std::string, bool,
+                    wrapped_int<std::int64_t>, wrapped_int<std::uint64_t>, double, std::allocator >;
     std::string data = "[1,2,-3,-4]";
-    json as_json = json::parse(data.begin(), data.end());
+    my_json as_json = my_json::parse(data.begin(), data.end());
     wrapped_int<std::uint64_t> i1 = as_json[1];
     wrapped_int<std::int64_t> i2 = as_json[2];
     CHECK(i1 == wrapped_int<std::uint64_t>(2));