After changing to the latest compiler supported by linter-solidity (0.4.1) "assert" and "require" are still being high-lighted as an undeclared identifier. I tested the same code over in browser solidity and using their 0.4.1 compiler there are no errors.
Edit: I had previously included "require" as also exhibiting the same error as "assert". Please disregard that as it does appear to be working.
I was testing the SafeMath contract found here: https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/math/SafeMath.sol
After changing to the latest compiler supported by linter-solidity (0.4.1) "assert" and "require" are still being high-lighted as an undeclared identifier. I tested the same code over in browser solidity and using their 0.4.1 compiler there are no errors.