This fixes a scenario when INVISIBLE_REFERENCE is suppressed, but we
resolved to the wrong overload because when none of the candidates were
applicable, more or less the first one was chosen.
Because we call `fullyProcessCandidate` on the candidates, their
applicability can change which can lead to a situation where the
applicability of a ConeAmbiguityError is different to all its
candidates. The changes in coneDiagnosticToFirDiagnostic.kt account for
that, otherwise code like candidates.first { it.applicability ==
CandidateApplicability.UNSAFE_CALL } can throw NoSuchElementException.
#KT-57776 Fixed
tl;dr the current design of klibs does not allow to properly deserialize
the list of sealed subclasses in a sound way. It is possible that
a subclass of a sealed class is declared in a different file, AND is
private in that file.
A more detailed explanation:
Right now we don't serialize file signatures at all.
However, a private declaration's signature must necessarily include
the file signature.
How do we serialize a private declaration's signature into a klib
and deserialize it later?
**Serialization** is simple: we just serialize the file signature as
an empty protobuf message.
When we are **deserializing** a private declaration, we look at the file
that is being deserialized right now, and construct the file signature
based on that.
This logic, however, doesn't always work. An example is KT-54028.
Basically, if we have a sealed interface with a private implementor
declared in a different file, this breaks:
1. We are deserializing the sealed interface. The deserializer knows
that we are now in the file in which the sealed interface is declared.
2. As part of deserializing the interface, we deserialize its sealed
subclasses.
3. Naturally, we come to deserializing the private implementor that is
declared in another file, but the deserializer still thinks that we are
in the file in which the interface is declared. A wrong signature is
created, which leads to linkage failure.
We *could* fix this by properly serializing the file signature,
i.e. instead of an empty protobuf message we could write the file path
and its package to the klib. However, there a problems with this
approach:
- The current design of signatures allows a situation where two
different files can have the same relative path
(for example, with the help of the `-Xklib-relative-path-base` compiler
flag) *and* the same package, which would introduce ambiguity during
linkage.
- Most importantly, this appoach won't work well with incremental
compilation of klibs. Currently we rely on the assumption that all
cross-file references are handled with public signatures, and private
signatures are only used inside a single file. This allows to move
declarations across files without recompiling it's use sites.
It has been decided to apply the following hacky solution: we just don't
deserialize the list of sealed subclasses from klibs.
The list of sealed subclasses is not used in lowerings, so it should be
safe.
#KT-54028 Fixed
Overriding equals, hashCode, toString and any other member that is not
expect does not require satisfying the rules of expect-actual matching.
#KT-57381 Fixed
with dedicated opt-in language feature and special
annotation or module capability.
Not intended for a general use, solves specific K/N
scenario with interop libs.
#KT-55902 fixed
A::foo is preferably resolved as an unbound reference to A.foo, however
if A.Companion is a subtype of A and the expected type has one fewer
parameter than the type of the unbound reference, generate a bound
reference with the companion as receiver.
^KT-56519 Fixed
The expression needs to be resolved first to determine if there is a
receiver that needs to be extracted to a temporary variable. Also, the
special case for prefix increment/decrement on local variable without
delegates requires resolution to check if the variable is local.
^KT-56771 Fixed
^KT-56659 Fixed
Kirill Rakhman