Currently, all tests are relative to `./tests/functional` instead of
`./tests/functional/lang`. Whether this is a historical artefact or as
intended, the current move is to align the tests with the new design of
functional2, preparing them for an easier migration.
Change-Id: Ie394691b071488a8000a005080b9167786d5bd9a
this is much more useful than a frame pointing to the set but claiming
it as a function being called. if the function is actually at fault we
will now point to its attribute, although the position may be slightly
wrong if __toString was defined from set updates or builtin functions.
Change-Id: Ib3eb237a276d94426d9c6fc0e26eea72382d34a2