Otherwise, exception from org.jetbrains.kotlin.resolve.calls.inference.components.ConstraintInjector.TypeCheckerStateForConstraintInjector.fixedTypeVariable
might happen during forks resolution
The test data is extracted from intelliJ FP test
^KT-43296 Fixed
Otherwise, OVERLOAD_RESOLUTION_AMBIGUITY is reported for the calls to
the functions annotated as @OverloadResolutionByLambdaReturnType
^KT-43296 In Progress
The idea is that we should not fix (i.e. choose any of the fork branches)
on the stage of candidate processing before completion, but it's enough
just to check that current state can be converged to success.
And when completion starts, and we add expected type to the system,
we've got more information to choose the correct fork branch.
NB: The old `processForkConstraints` is being called just
at the beginning of the completion phase.
^KT-43296 In Progress
It's anyway safe to use avoidComprehensiveCheck = true because
during deserialization we're sure that we need DNN type because
it's been serialized as such.
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
`x?.y != null` does not imply that `x != null` if e.g. an argument to
`y` has reassigned `x` in the meantime.
The same is true for `x == y` and `functionWithContract(x, y)`, but
those are somewhat harder to implement since there is no easy way to
find the last node of a certain argument.
^KT-55096
This makes the `returns() implies` checker slightly cleaner, and also
fixes the case that I've missed where in RHS of `x ?:` type of `x` was
not set to `Nothing?`.
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
val c = C("...")
val d = c
if (c.x == null) return
c.x.length // c.x has type String
d.x.length // d.x -> c.x through d -> c
c = C(null) // remove alias d -> c
d.x.length // info from c.x moved to d.x
^KT-54824 Fixed
vladislav.grechko