It would be more consistently to prohibit the behavior from the unmuted
test (see KT-52428), but it was decided to postpone the breaking change.
Unfortunately, it didn't work to make a test where for computing
star projections we would need to substitute other type parameters
because effectively, it's not allowed to have SAM conversion when
star projections/wildcard is based on a type parameter which bounds
use other type parameters.
^KT-53552 In progress
After we added "careful approximation of contravariant projections" in
584b70719e, some SAM conversions started to require an additional
implicit cast of the functional value before it is converted to the SAM
interface. The target type of this implicit cast was computed
incorrectly because it didn't contain nullability of the SAM type. This
could lead to a situation where a nullable value was incorrectly cast to
a non-null type, which caused a missing null check and NPE at runtime.
For example, let's consider the test `kt54600.kt`. SAM conversion
happens in the constructor call `J(filter)`. Before 584b70719e, the IR
for that argument was (irrelevant things are omitted for simplicity):
TYPE_OP SAM_CONVERSION type=Condition<String!>!
GET_VAR filter type=Function1<String, Boolean>?
After 584b70719e, the IR became:
TYPE_OP SAM_CONVERSION type=Condition<Any?>!
TYPE_OP IMPLICIT_CAST type=Function1<Any?, Boolean>
GET_VAR filter type=Function1<String, Boolean>?
Note the two changes:
* The resulting SAM type changed from `Condition<String!>` to
`Condition<Any?>`. This is exactly the point of the "careful
approximation" change, because just erasing the "in" projection from
the parameter type is incorrect, see the explanation for that change.
* The value is now implicitly cast to the _non-null_ function type
before it is SAM-converted. The presence of the cast is fine, but the
fact that it's to a non-null type is an oversight.
The target type for this cast is computed at
`KotlinType.getSubstitutedFunctionTypeForSamType` in psi2ir. Now it
extracts the nullability from the SAM type and retains it in the
resulting function type.
After this change, the IR for the argument becomes:
TYPE_OP SAM_CONVERSION type=Condition<Any?>!
TYPE_OP IMPLICIT_CAST type=Function1<Any?, Boolean>!
GET_VAR filter type=Function1<String, Boolean>?
Note that the target type is now flexible, as the resulting SAM type.
Another option would be to make it nullable, as the type of the
functional value, but there doesn't seem to be any difference.
#KT-54600 Fixed
This is what Java 15+ does, and it permits accessing captured type
parameters via reflection. The alternative is to emit generic signatures
on the lambda methods, but that was disabled and I have no clue why.
^KT-52417 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.
Also, do not try to use invokedynamic on SAM calls with intersection
types, because intersection type is not allowed as an immediate type
projection of a supertype, and constructing a fake override in
LambdaMetafactoryArgumentsBuilder led to an exception. This fixes the
problem which was worked around earlier in e6c089ef, effectively
reverting that commit.
The main motivation for this change is that LambdaMetafactory also
doesn't generate generic signature for SAM wrapper classes at runtime.
Since these classes are synthetic, nobody should rely on the fact that
they have generic supertypes, which was observable only via Java
reflection.
#KT-46149 Fixed
#KT-46238 Fixed
Pass parentContext to SamWrapperCodegen from the outside instead of
using the one from parentCodegen. The difference is that in case of an
inline lambda, we're creating an InlineLambdaContext whose parent is a
ClosureContext, but the codegen for that lambda has that latter
ClosureContext as its context. So the getNonInlineOuterContext call in
SamWrapperCodegen.generateInnerClassInformation wasn't able to identify
that this is a context of a lambda that needs to be skipped, and
generated it as EnclosingMethod, which caused Java reflection to fail
because once that lambda was inlined, it was removed and thus didn't
make it to runtime.
#KT-44827 Fixed
In tests merged from boxAgainstJava in 29b96aa1, some directories were
named slightly differently compared to box, e.g. "property" vs
"properties", "varargs" vs "vararg". This change renames these, moves
some of the tests to more fitting directories, and also renames
"visibility" to "javaVisibility" because it's about Java visibilities
specifically.
Note that only irrelevantStaticProperty.kt failed before this change.
Having private declarations caused no problems, but it seems incorrect,
so it's fixed now and irrelevantPrivateDeclarations is added just in
case.
#KT-41848 Fixed
Denis.Zharkov