This is basically a workaround for a slightly different IR generated by
fir2ir vs psi2ir. Simplified, psi2ir generates something like this for
the sample from KT-59218:
TRY type=Unit
try: BLOCK type=Unit
VAR methodHandle [...]
TYPE_OP type=Unit origin=IMPLICIT_COERCION_TO_UNIT
CALL invokeExact [...]
While fir2ir generates the following:
TYPE_OP type=Unit origin=IMPLICIT_COERCION_TO_UNIT
TRY type=Any?
try: BLOCK type=Any?
VAR methodHandle [...]
CALL invokeExact [...]
The lowering relies on the fact that a polymorphic call (`invokeExact`
in this case) is a direct argument to the TYPE_OP, to determine the
correct return type (Unit in this case) to be generated in the bytecode.
The solution here is to push the type coercion "through" all the
block-like structures (`try`, `when`, container expression) so that if
the last statement in the block is a polymorphic call, it gets properly
converted even if the whole block is under a type coercion operation, as
it happens in fir2ir. We achieve that by using the "data" parameter of
the IR transformer: appropriate immediate children of
IrTypeOperatorCall/IrTry/IrWhen/IrContainerExpression get the type that
the expression needs to be coerced to, and all the other expressions
ignore that type and set it to null when transforming their children.
A proper solution would be to ensure fir2ir generates exactly the same
IR as psi2ir (KT-59781), but since PolymorphicSignatureLowering is the
only lowering affected so far, and polymorphic calls occur very rarely,
it seems safe to workaround it in the lowering for now.
#KT-59218 Fixed
We are going to deprecate `WITH_RUNTIME` directive. The main reason
behind this change is that `WITH_STDLIB` directive better describes
its meaning, specifically it will add kotlin stdlib to test's classpath.
This works in many cases, however, it is incomplete since there
are cases where classes are extracted to top-level and therefore
reparented. Therefore, we lose the information about the function
class are nested inside.
Sergej Jaskiewicz