Instrumentation appears to be breaking constants

I have a library as follows

pragma solidity ^0.4.18;

import 'zeppelin-solidity/contracts/token/ERC20.sol';


library KeyUtils {
    address constant private KEY_ADDRESS = 0x0;

    function getKEY() internal pure returns (ERC20) {
        return ERC20(KEY_ADDRESS);
    }
}

and normal tests of this run fine.

But when I run with solidity-coverage I get this error

/Users/davesag/src/myawesomeproject/coverageEnv/contracts/utils/KeyUtils.sol:13:5: TypeError: Library cannot have non-constant state variables
    address private KEY_ADDRESS = 0x0;
    ^-------------------------------^
Compilation failed. See above.

Somehow the instrumentation process appears to have removed the constant keyword.

[cgewecke]

@davesag Thanks so much for reporting this and @area thank you for fixing. Please re-open there continue to be issues:

Published in 0.4.1

[cgewecke]

@area That’s looks great - does it work for the edge case elena raised here?