Re: WTF: dmd 2.066 vs. dmd 2.067 really dangerous code breakage

[w0rp via Digitalmars-d]

You really should pay attention to the deprecation messages. 
immutable was unfortunately used as if it was a manifest constant 
before, but it ought to be a member of a struct, and that 
behaviour is changing. There's been a deprecation message there 
for a while, now the behaviour is changing, and eventually you'll 
be able to create immutable members of structs without any 
warnings, as it will just use the new behaviour.