mirror of
https://github.com/nlohmann/json.git
synced 2026-08-28 20:07:32 +00:00
Niels Lohmann
43afb5bebc
object_t is probed for key_compare inside the definition of basic_json, so it is instantiated while basic_json is still incomplete. Whether a hash map survives that depends on the standard library: libstdc++ 9 needs the size of the mapped type to instantiate std::unordered_map's node type and rejects the adapter, which broke the GCC 9 builds. The test now derives its no-key_compare object type from std::map -- which does cope -- and shadows the inherited key_compare member type with an entity that is not a type, so the library's probe finds none, exactly as for a hash map. The unflatten() order-independence checks in unit-json_pointer already cover the behaviour that the unordered object type was there for. The limitation is documented for std::unordered_map. Also address two Clang-Tidy findings the earlier commits introduced: erase_from_object() declares its iterator with auto, and at(size_type) checks the type first and then falls through to the return instead of throwing from an else branch. Signed-off-by: Niels Lohmann <mail@nlohmann.me>