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Compilation of methods per class.

re: There was a horrible bug in Victoria Day PCL which had symptoms like
    what you are mentioning --- an entry could be in the cache, but there
    would still be a cache miss.  I recall that bug being fixed, but I don't
    know if the patch was widely distributed.

The behaviour I'm referring to was present in previous versions too 
(at least one -- maybe more).  It wasn't really a bug in that it would 
still correctly find the cached entry; but it was a performance pitfall
in that it had to go out of line at unpredictable times to do it.

Lucid's CLOS uses a different approach to generic function "caching",
which doesn't follow any of the PCL versions nor of that referred to in 
the L&FP90 paper.  Rather, it is more akin to TICLOS's.  Method-functions 
and other data are being "cached" (in a general sense) from the lookup
phase; but the data-structure in which the cached entries are stored is a 
hash-table rather than a cache.

-- JonL --