Using FPC 3.0.4, I very often get this Error:
(not sure it is always that unit, but always RTTI_......)

(9015) Linking ..\lazarus.exe
B:\lazarus_latest_svn_2\ide\lazarus.pp(167,1) Error: Undefined symbol: RTTI_$FPDBGDWARFDATACLASSES_$$_DEF787
B:\lazarus_latest_svn_2\ide\lazarus.pp(167,1) Error: Undefined symbol: RTTI_$FPDBGDWARFDATACLASSES_$$_DEF786
B:\lazarus_latest_svn_2\ide\lazarus.pp(167,1) Fatal: (10026) There were 2 errors compiling module, stopping
Fatal: (1018) Compilation aborted

"lazarus.pp(167,1)" is the last line "end." of the "program" file. So that is when all compiling should be done.

FPDBGDWARFDATACLASSES is a unit.
There is only one .ppu and one .o file for that unit.

The unit was re-compiled (according to ppu timestamp), and that is correct as a unit in its uses clause had changed.
(this unit itself did not change)

The only files containing this text are
- the previous successfully build exe
  for one of the strings (...786) also the pre-previous exe (i.e. altogether the last 2 successful builds)
- the file "fpdebugdebugger.o"
  which according to the timestamp was NOT rebuild.

But the IDE did rebuild the file "LazDebuggerFp.pas" (log + timestamp of ppu).
And that is the package mainfile, that contains:
    uses
       FpDebugDebugger, LazarusPackageIntf;
So fpc should have seen that FpDebugDebugger needed to be rebuild?

FpDebugDebugger has FpDbgDwarfDataClasses in its "uses".

Any idea?