I've experimented few things and here's the results (both abilities is set to Never Miss);
1. Critical Strike with 100% chance to proc will never hit an enemy with 100% evasion.
2. Bash with 100% chance to proc will hit an enemy with 100% evasion.
3. Bash with non-100% chance to proc will only hit enemy unit with 100% evasion if the proc occurs, else, it will become 'miss'.
In DotA, I think they separate the ability to counter result #3.
In DotA, there's 25% chance to proc 100 bonus damage and stuns the target for 0.01s, right ?
But that bonus won't proc on 100% at all times, this is something they code to counter it.
I don't know how, more experiments coming (if I'm not lazy).