Unused variables, better as error or warning?

[bearophile]

Walter Bright: 
> Then you're faced with one of two unpleasant consequences:

Just a note. If small parts of the type system are with Phobos or user defined D code that used the static introspection I have explained a bit here:
http://www.digitalmars.com/webnews/newsgroups.php?art_group=digitalmars.D&article_id=115833
Then there is no portability problem of the warnings across different compilers, because they are part of the program (or the std lib) so you move them around with the code, across different compilers.

Bye,
bearophile