`INVISIBLE_REFERENCE` may be reported due to CandidateApplicability via
a ConeDiagnostic, or in a checker. The former leads to
`FirErrorResolvedQualifier`, so the checker is not called.
This makes little sense, because CandidateApplicability may result in
`NO_COMPANION_OBJECT`, which would prevent other more meaningful
diagnostics from being reported (like `API_NOT_AVAILABLE`).
If we run checkers for `FirErrorResolvedQualifier` we may get duplicate
`INVISIBLE_REFERENCE`. The change in the checker prevents it.
Callable symbols with SinceKotlin are filtered out by a
resolution stage, but in K1 classifiers and property accessors
report API_NOT_AVAILABLE. K2 filters out properties with
unavailable accessors, but does nothing for classifiers.
This change fixes it.
^KT-54410 Fixed
Previously it wasn't reported in FIR for ConcurrentHashMap inheritors
because the receiver id hasn't matched CHM.contains id
Fixed by unwrapping origin of the call in case of fake overrides
^KT-55606 fixed
* `return` should only be added to the last statement if the return
type is not Unit
* If there is a `return` without an argument, then the expected return
type is Unit and the last expression is not a return argument (unless
it's an incomplete call, in which case it is inferred to return Unit;
this behavior is questionable, but inherited from K1)
* There should be a constraint on return arguments even if the expected
type is Unit, otherwise errors will be missed
* When the expected type is known, using the call completion results
writer is pointless (and probably subtly wrong).
^KT-54742 Fixed
I.e. maintain a set of seen lambdas where each marked as either "data
flow only" or "both data and control flow". The latter are truly
parallel with the function being analyzed, while the former have
technically already terminated, we just don't know the types inside them
because they may not have been analyzed yet.
Also remove incorrect subtype check checkers
Test unsafeVarianceInAliasedFunctionalType.kt started to fail because
of KT-54894. This bug existed before, changes from this commit just
unhided it (previously it was hidden because incorrect subtype check
in `isSubtypeForTypeMismatch` which is used by FirFunctionReturnTypeMismatchChecker
This also fixes some returnsNotNull contracts because the old code added
an implication that `== true` => `!= null` then promptly removed any
statement that this could've affected if the argument was a synthetic
variable.
^KT-26612 tag fixed-in-k2
In theory, forking persistent flows should be cheap because of object
reuse, so the proposal here is to start from scratch and prove
redundancy of forks on a case-by-case basis. Something something better
safe than sorry.
^KT-28333 tag fixed-in-k2
^KT-28489 tag fixed-in-k2
Note: in this test, we create a flexible type from two captured types
during substitution, which provokes exception from
FlexibleTypeImpl.runAssertions() (they are run only in test mode)
Related to KT-54198
Nikolay Lunyak