DMD diagnostic - any way to remove identical lines from final dmd error log?

[Dmitry Olshansky]

I seriously consider writing a simple postprocessor for dmd's output.
Once dmd became able to recover from errors and crawl on it started to 
produce horrific amounts of redundant text on failure.

Observe for instance that there are only 6 + 2 = 8 lines of interest:

uni.d(3699): Error: template instance uni.icmp!(char,wchar) error 
instantiating
uni.d(3683): Error: undefined identifier fullCasedMatch
uni.d(3686): Error: undefined identifier fullCasedMatch
uni.d(3699): Error: template instance uni.icmp!(char,dchar) error 
instantiating
uni.d(3683): Error: undefined identifier fullCasedMatch
uni.d(3686): Error: undefined identifier fullCasedMatch
uni.d(3699): Error: template instance uni.icmp!(wchar,char) error 
instantiating
uni.d(3683): Error: undefined identifier fullCasedMatch
uni.d(3686): Error: undefined identifier fullCasedMatch
uni.d(3699): Error: template instance uni.icmp!(wchar,wchar) error 
instantiating
uni.d(3683): Error: undefined identifier fullCasedMatch
uni.d(3686): Error: undefined identifier fullCasedMatch
uni.d(3699): Error: template instance uni.icmp!(wchar,dchar) error 
instantiating
uni.d(3683): Error: undefined identifier fullCasedMatch
uni.d(3686): Error: undefined identifier fullCasedMatch
uni.d(3699): Error: template instance uni.icmp!(dchar,char) error 
instantiating

I'd ideally see this:

uni.d(3683): Error: undefined identifier fullCasedMatch
uni.d(3686): Error: undefined identifier fullCasedMatch
--- !! During instantiation of ---
uni.d(3699): template instance uni.icmp!(char,dchar)
uni.d(3699): template instance uni.icmp!(char,wchar)
uni.d(3699): template instance uni.icmp!(char,dchar)
uni.d(3699): template instance uni.icmp!(wchar,wchar)
uni.d(3699): template instance uni.icmp!(wchar,dchar)
uni.d(3699): template instance uni.icmp!(dchar,char)
-------
... other errors

Other food for thought is to try to indicate explicitly which errors
are related vs unrelated, which are collateral, like failed template 
instantiation that rolls out the whole path of failure (but one have to 
read the text carefully to get where it starts).

-- 
Dmitry Olshansky