To be more precises, ResultTypeResolver for K2 now searches for
similar LOWER/UPPER constraints pair based on the same flexible type,
like LOWER(CapturedType&Any..CapturedType?) and UPPER(CapturedType!).
If such a pair is found, the CapturedType is not approximated.
This is done to avoid a big difference between this case and
completely same constraints, like LOWER(CapturedType!) and
UPPER(CapturedType!). In this case we squash them to EQUAL(CapturedType!)
even before ResultTypeResolver, and captured types which is got from
an EQUAL constraint are not approximated even before this commit.
This commit fixes back a case from KT-50134 and a problem with intellij.vcs.git
#KT-65596 Fixed
This commit changes the behavior of KT-59138 effectively declining it in 2.0.
However, we plan to implement KT-59138 behavior under a feature
flag in 2.0 (see KT-66447), and switch this feature on version 2.x.
Also, this commit implements the LC resolution about postponing
KT-57014 change. We don't have KT-57014 described behavior in 2.0 anymore.
However, we plan to implement a deprecation warning here, see KT-65578.
After this commit, 6 diagnostic tests become incorrectly broken:
- 5 tests from PurelyImplementedCollection group
- a test platformTypes/nullableTypeArgument.kt
This commit also breaks currently fixed-in-k2 KT-50134
(it is fixed again in the following commits),
as well as KT-58933 (it will remain not fixed till we enable KT-59138
behavior again).
#KT-65596 In Progress
#KT-57014 In Progress
#KT-58933 Submitted
Note that `FlexibleNullability` doesn't
exist anymore: it was removed at
`65ea4e18`.
`preserveEnhancedNullability = true`
was needed because if we have an
`@EnhancedNullability DNN`, and we
substitute something into it, then
`withNullability` is called there becase
that's how DNNs work, not becase we want
to obtain some new type with a
different nullability.
This is backed by
the `compiler/testData/diagnostics/tests/j+k/integerNotNullable.kt` test
where we first have
`@EnhancedNullability T & Any`, then
we substitute `{T -> kotlin/Int!}` and
then inside
`org.jetbrains.kotlin.fir.resolve.substitution.AbstractConeSubstitutor#substituteOriginal`
(this is a DNN-specific function) we
call `withNullability(NOT_NULL)`,
and expect the attribute to be preserved. Otherwise this test would
fail with
`OVERLOAD_RESOLUTION_AMBIGUITY` for
`IntBox().put(1)`.
^KT-50221 Fixed
Merge-request: KT-MR-11272
Merged-by: Nikolay Lunyak <Nikolay.Lunyak@jetbrains.com>
Mikhail Glukhikh