Redundant constraints generated

[etorreborre]

@waddlaw I'm opening a new issue to deal with this redundant constraint warning that I observed after #11

 • Redundant constraints: (HasCallStack, HasCallStack)
    • In the type signature for:
           contractConfig :: (HasCallStack, HasCallStack, HasCallStack) =>
                             ContractConfig
    |
225 | contractConfig :: ContractConfig
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[abhin4v]

I also see this unused imports warning as well, which is possibly related to this issue.

warning: [-Wunused-imports]
    The qualified import of ‘GHC.Stack’ is redundant
      except perhaps to import instances from ‘GHC.Stack’
    To import instances alone, use: import GHC.Stack()