Make "failed with no transactions made" error more explicit

I'm getting the following error:

> failed with no transactions made ⁉️

I looked at the the [related GitHub issues][1] but I am now even more confused than before.

I made sure that the child contract I used to inherit from my main contract has a dummy constructor, as per the instructions given in the [crash course][2]:

```solidity
contract FintrollerInvariants is Fintroller {
constructor() {}

function echidna_liquidation_incentive() external view returns (bool) {
return
liquidationIncentiveMantissa >= liquidationIncentiveLowerBoundMantissa &&
liquidationIncentiveMantissa <= liquidationIncentiveUpperBoundMantissa;
}
}
```

Is there anything wrong with [my invariants contract][3]?

[1]: https://github.com/crytic/echidna/issues?q=failed+with+no+transactions+made
[2]: https://github.com/crytic/building-secure-contracts/blob/master/program-analysis/echidna/how-to-test-a-property.md#write-a-property
[3]: https://github.com/MainframeHQ/mainframe-lending-protocol/blob/828bce3abb1d6d81003c166cdd80c354cde8a7f6/contracts/invariants/FintrollerInvariants.sol