The module is configured to run a bunch of test suites defined as API pairs. Currently those are `CURRENT API` – `CURRENT IMPL`, `CURRENT API` – `1.9.20 IMPL`, `1.9.20 API` – `CURRENT IMPL`
^KT-61860 In Progress
This way it is easier to understand where `notifyAnalysis*`
methods were called. Also, in K1, we are not including
`checkKotlinPackageUsageFor*` in the analysis time.
`recordAssignments` merges properties into all parents which is
redundant work in the case of empty `VariableAssignments`.
This redundant work leads to critically poor performance in cases
with many local declarations.
^KT-66416 Fixed
`T.() -> R` and `(T) -> R` should only be
different for resolution, but casts are only
about typechecking. Values of either of
these types can always be put into variables
of the other type.
PCLA-related changes led to this change in
behavior. In K1 an explicit cast was needed
to prevent ORA, but now in K2 this code
is green without casts.
^KT-50293 Obsolete
Otherwise, bootstrapping fails.
This condition is `false` because of
`require(this is ConeKotlinTypeProjection)`,
since `ConeKotlinTypeProjection` is its
sibling, not a subtype.
This way it's easier to reason about where
useless casts/is checks come from, because
everything is on the same screen.
`USELESS_CAST` disappeared from
`FirPsiJsOldFrontendDiagnosticsTestGenerated.testDynamicCastTarget`
because
`LanguageFeature.EnableDfaWarningsInK2`
is disabled, and previously it only
affected `FirCastOperatorsChecker`, but
not `FirUselessTypeOperationCallChecker`,
which felt like an unintended mistake.
A related issue: KT-50965
This makes it more consistent and fixes some
overlooked corner cases. Also it was decided
on the last equality applicability DM
(KT-62646) that we'd like
`is`/`!is`/`as`/`as?` to work similarly
to `===`/`!==`.
Also note that it now gives a clearer
explaination of why some corner cases work
the way they do. For example,
`FirPsiDiagnosticTestGenerated.testLambdaInLhsOfTypeOperatorCall`
yields `UNCHECKED_CAST` instead of
`CAST_NEVER_SUCCEEDS`, because
`toTypeInfo()` replaces all type arguments
with star projections, even when the argument
is not a type parameter. This is because
it has been desided to work this way in
KT-57779.
In
`FirPsiOldFrontendDiagnosticsTestGenerated..NeverSucceeds#testNoGenericsRelated`
the diagnostic is introduced, because
`t2 as FC1` and `FC1` is a final class with
no `T5` supertype.
`UNCHECKED_CAST` in
`FirPsiOldFrontendDiagnosticsTestGenerated.testSmartCast`
disappeared, because previously we didn't
take smartcasts into account.
Note that
`FirPsiOldFrontendDiagnosticsTestGenerated.testMappedSubtypes`
is a false positive. It appears because `isSubtypeOf()` doesn't
take into account platform types in supertypes of the given types
(doesn't map them).
Most probably it was there just to guarantee
that if `argument` is not a smartcast
expression then this property is exactly the
same thing as `originalType`, but it seems
there's not much point in that as none of
the tests fail.
`lowerThanBound()` was renamed to:
- draw attention to its corner cases
- make its single usage less cryptic
We may want to reserve the pretty name for
a function that, for example, returns `true`
if `argument` suits all the bounds.
Similarly, `canHaveSubtypes()`
does some questionable logic in case of
`INVARIANTxINVARIANT`: some hypothetical
`Inv<Foo>` doesn't have subtypes so
checking "Foo has subtypes strictly above
Nothing || Foo has supertypes strictly below
the parameter bounds" doesn't seem correct.
`Foo` may have some, but `Inv<them>` are
not related to `Inv<Foo>`.
Alexander.Likhachev