Safe Haskell trust

[Fabian Bergmark]

Im using the Hint library in a project where users are able to upload
and run code. As I don't want them to do any IO, I run the interpreter
with -XSafe. However, some packages (in my case aeson) are needed and
I therefore tried marking them as trusted with ghc-pkg trust aeson.
This seems to have no effect however and the interpreter fails with:

Data.Aeson: Can't be safely imported! The module itself isn't safe

Is there any way to get XSafe-like guarantees with the ability of
allowing certain packages?