[Lazarus] TAChart compilation error (issue 22365)

[Alexander Klenin]

Issue http://bugs.freepascal.org/view.php?id=22365 was about the
compilation error
when the TAChart code is compiled by FPC trunk.

I did not notice the issue in time, because bug tracker is unusably slow,
so I use Google Alerts to track bugs. This usually works, but sometimes causes
a delay of a few days before Google notification. Sorry for that.

The issue is resolved, so it is impossible to discuss -- this is why I
start discussion here.
I Cc'd original reporter -- hopefully he does not mind.

I am grateful for Mattias for stepping up and resolving the issue,
but I'd appreciate some discussion for such controversial changes.

Regarding the specifics of the problem -- FPC trunk (suddently?)
stopped compiling
TAChart source. Affected code did not change recently, so this is
either a FPC regression
or some general issue like out-of-date object files, wrong
installation paths leading to version conflicts etc.
So I have a few questions/suggestions:
1) Can anybody (Mattias?) reproduce this?
2) Why did this suddently happened? Why do not all other trunk users complain?
3) Can this be isolated to a smaller testcase and reported as an FPC bug?
4) Alternatively, is this an intentional backwards-incompatible change
in FPC? Should it be documented as such?
5) If the bug is too subtle/hard to fix, at least the workaround in TAChart code
  should be clearly marked as such -- there are a few examples in
TAChart, search for 'workaround'

-- 
Alexander S. Klenin