Do not try to find PSI element, but always use the IR element offsets
instead. This greatly simplifies test data because we don't need to have
custom PSI- and LT- based diagnostic ranges in every test, and K1/K2
behavior also is mostly the same.
The exact offset ranges are not as important for backend diagnostics, so
it's better to have K2+PSI and K2+LT behaving the same.
In the vast majority of tests, diagnostics are reported at a slightly
different location in LT vs PSI. This is because in the light tree mode,
backend errors are reported basically on the start of the IR element,
which is for example the keyword "class" for a class and not its name as
in K1 or in K2+PSI. Similarly, the end of the diagnostic is at the
ending offset of the IR element.
Normally it would be a bit user-unfriendly to highlight the whole class
as red, starting from the keyword "class" and ending with the closing
brace "}". But remember that these are backend diagnostics in the K2+LT
mode, which is only possible in the compiler scenario, not in the IDE.
And in this case, the ending offset doesn't matter at all because it's
not presented to the user, and minor change in the starting offset is
not a problem as well.
There are some tests which legitimately fail in the LT mode because the
corresponding diagnostics haven't been supported. They will be dealt
with in subsequent commits:
testPropertyInlineCycle
testInlineCycle
MultifileClasses.testJvmSynthetic
testSuspendInlineCycle
testIndirectInlineCycle
#KT-59586
Alexander Udalov