220.127.116.11: more error reporting tweakery
* Now that *CURRENT-PATH* is bound first by PROCESS-TOPLEVEL-FORM
make FIND-ERROR-CONTEXT prefer NODE-SOURCE-PATH *CURRENT-PATH* --
otherwise the more accurate source path in the node is never used.
(Experimentally it seems that *CURRENT-PATH* is never more
Everything seems OK, but the whole source path mechanism could
probably us an audit, and possibly some refactoring.
* ADD-TEST-CONSTRAINTS should bind *COMPILER-ERROR-CONTEXT* around
the call to SPECIALIZER-TYPE in case of undefined types. (Left out
from last patch by accident.)