std::shared_ptr<T> == nlohmann::json compiles, which seem undesirable

[drussel]

Specifically std::shared_ptr<nlohmann::json>() == nlohmann::json() compiles (where one forgot to deference the shared_ptr before comparing).

What is the issue you have?

It is easy to miss dereferencing the pointer and so have the comparison not be as desired.

Please describe the steps to reproduce the issue.

std::shared_ptr<nlohmann::json>() == nlohmann::json()

Can you provide a small but working code example?

std::shared_ptr<nlohmann::json>() == nlohmann::json() (which is true) or std::make_shared<nlohmann::json>() == nlohmann::json() (which is false)

What is the expected behavior?

A compilation error would be really nice as it is very likely a bug.

And what is the actual behavior instead?

Compiles (as far as I know, the comparison result is what you would expect given that it compiles.

Which compiler and operating system are you using?

• Compiler: apple-clang 12,13. Visual Studio 2017. Gcc 9.
• Operating system: various

Which version of the library did you use?

• latest release version 3.10.2
• other release - please state the version: 3.9.1
• the develop branch

If you experience a compilation error: can you compile and run the unit tests?

[gregmarr]

This is due to the implicit conversions/constructors in the library. If you disable them, then this code no longer compiles. See here for how to disable them:
https://github.com/nlohmann/json#implicit-conversions

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[maddanio]

so this issue can be closed, right? works as designed?

[drussel]

Works as designed and I can’t think of a better design.