[pilif]

True for languages which are case-sensitive.

Other languages like PHP (partially), BASIC or Pascal are case insensitive, so lookup has to be done case-insensitively which means that case has to be normalized, so transforming case of identifier becomes necessary. If it can't be done consistently, that's a problem.

[klmr]

So you use a culture-invariant locale for parsing. Still not a problem.

[pilif]

How do you lowercase in a culture-invariant locale? Or do you mean english?

[mikeash]

No matter how you do it, a class name should always match when looked up with an identical string.