Test suite fails to compile

I get the following build error, trying to compile and run the test suite:

```
In-place registering sparse-0.9...
Preprocessing test suite 'properties' for sparse-0.9...

tests/properties.hs:16:8:
Could not find module `Instances'
Use -v to see a list of the files searched for.
```

This seems like a missing module?

Start with tests/properties.hs, especially its import of the missing Instances module, and reproduce the test-suite compilation error. Trace how the test suite resolves its modules and confirm the build completes and the properties tests run without the “Could not find module `Instances'” error.

Written by the indexing model from the issue text.