D not considered memory safe

[Walter Bright]

Those are good suggestions, but I've been trying to make dmd @safe now for a 
while. With all the inheritance going on, and the flow graph cycles, your 
suggestions are not workable.

For programs that have an acyclical graph, and little inheritance, your 
suggestions are more tractable.

Just making `toChars()` safe has turnout to be a major undertaking.