Description
SLS 4.1 currently allows all types of constant expression to be the RHS of a constant value definition. This includes literal arrays and identifiers of constants which in turn are literal arrays.
However, as discussed in #3183 and recently on Gitter, the compiler actually does not treat final val definitions of literal arrays as "true" constants, because (as far as I understand) it appears difficult/impossible to ensure that they are actually not mutated.
After discussion with @retronym, the suggestion is to update the spec to clarify that literal arrays (and identifiers of constants which in turn are literal arrays) are not valid expressions for a constant value definition (although they would continue to be valid constant expressions in their own right).
/cc @som-snytt [~lihaoyi] @lrytz