[Lazarus] how to delete codetools source cache?

[David Emerson]

I use the matrix unit in my project, and from it the types 
tmatrix4_single and tmatrix4_vector

It is located here:
/usr/share/fpcsrc/3.0.0/packages/rtl-extra/src/inc/matrix.pp

Recently while debugging, codetools somehow got the wrong unit,
/usr/share/fpcsrc/3.0.0/tests/bench/shootout/obsolete/matrix.pp

I have been struggling with this for a couple hours now, and so I went 
ahead and deleted those obsolete shootout units. I definitely will never 
need them.

I closed and restarted lazarus.

But codetools seems to have cached the bad path. If I ctrl+return on 
uses matrix -- it prompts me, 'File 
"/usr/share/fpcsrc/3.0.0/tests/bench/shootout/obsolete/matrix.pp" not 
found. Do you want to create it?'

So codetools has cached this garbage path, and I have no idea how to 
reset/delete the path. I've grepped for "obsolete" in $HOME/.lazarus and 
I can't find any reference to the garbage path, but it persists.

So original question - how do I delete the codetools source cache... or 
whatever it's called?

Thanks!

~David.