This is a meta-bug. In std.string, there are a lot of functions that demand immutable arguments when they don't really need a guarantee that noone else has a mutable view of the string, and thus, const arguments would do just fine. Fixing this would make the const system seem like much of a straight jacket to newcomers without reducing safety.
Comment #1 by dsimcha — 2009-09-11T08:24:03Z
Forgot to mention, for stuff that returns some kind of string, array of strings, etc. that are aliased to the original, templates should probably be used to give the same guarantees about mutability that the original string had.