Yes, that is what I was trying to say.
I guess the decision to call the readonly keyword `const' was misleading in that, from the compiler's perspective, its value will not necessarily be known at compile-time.
Because it's more of a compiler-technical detail, a lot of programmers (myself included) are caught by surprise when their compiler gets angry about using a const, but not const expression, variable in a situation where a const expression is required.