Previously, because we didn't handle flexible types properly in
prepareCapturedType, projections inside flexible types would only be
captured during subtyping with captureStatus=FOR_SUBTYPING
which would lead to the constraint type being wrongly approximated
(see ConstraintInjector.TypeCheckerStateForConstraintInjector
.addNewIncorporatedConstraint).
Fixing the capturing produced two kinds of false positive diagnostics:
1. In ConstraintInjector.TypeCheckerStateForConstraintInjector
.addNewIncorporatedConstraint we would get two instances of cone types
that are structurally equal and containing the same captured type.
However, because we only skipped subtyping if the types were
referentially equal, we would get a contradiction here.
The fix was to use structural equality instead, which should be okay
as the captured type instances are the same.
2. Reified type variables were inferred to captured types because
flexible arrays with captured upper bounds
(Array<Foo>..Array<Captured(out Foo)>?) were not properly approximated.
#KT-62609 Fixed
FirDefaultArgumentsInExpectActualizedByFakeOverrideChecker is an adhoc
checker which can be converted to ExpectActualCheckingCompatibility to
reuse common expect-actual checking infrastructure.
^KT-62913 Fixed
Review: https://jetbrains.team/p/kt/reviews/13094/timeline
Tests that were broken by one of my previous commits are now fixed:
- actualFakeOverride_paramsAreCompatibleViaSharedMethodWithDefaultParams.kt
- inheritedJavaMembers.kt
DEFAULT_ARGUMENTS_IN_EXPECT_ACTUALIZED_BY_FAKE_OVERRIDE diagnostic
disappeared in delegation.fir.kt because only one
AbstractExpectActualChecker incompatibility can be reported at a time
(DEFAULT_ARGUMENTS_IN_EXPECT_ACTUALIZED_BY_FAKE_OVERRIDE is now reported
not by adhoc checker but by common AbstractExpectActualChecker). It
would be nice to report both of them, but it's a separate issue KT-62631
delegation2 test makes sure that
DEFAULT_ARGUMENTS_IN_EXPECT_ACTUALIZED_BY_FAKE_OVERRIDE is reported when
NO_ACTUAL_CLASS_MEMBER_FOR_EXPECTED_CLASS is fixed
- It became unused after cc70f78027
- And it's not going to become used in the nearest future, since in K2,
we won't have "member scopes" check on frontend (for now)
- Migrate ExpectActualCompatibility -> ExpectActualCheckingCompatibility
where the "checker" is expect
- Migrate ExpectActualCompatibility -> ExpectActualMatchingCompatibility
where the "matching" is expect
KT-62590 in progress. A lot of tests start to fail now. I will fix them
in next commits
Review: https://jetbrains.team/p/kt/reviews/12750/timeline
1. Support variance in ErrorListDiagnosticListRenderer.
I will make some diagnostics to have covariant type arguments in the
next commits
2. Drop unused code
Review: https://jetbrains.team/p/kt/reviews/12750/timeline
It should have been WeakIncompatible from the beginning because it's not
possible to overload by return type in Kotlin
This commit is a step forward to fix KT-62591
Unfortunately, the test cannot demonstrate the problem because of
another bug in K2 KT-59887
^KT-62752 Fixed
Review: https://jetbrains.team/p/kt/reviews/12750/timeline
Motivation:
It makes expect-actual matching-checking model more consistent.
expect-actual "matching" is run before FirResolvePhase.BODY_RESOLVE. You
can't know return types, until you run BODY_RESOLVE. That's why the
return type can't be checked during expect-actual matching. But it's
cursed: you have something that have to match by, but, at the same time,
you can't do it.
expect-actual "checking" is run after FirResolvePhase.BODY_RESOLVE.
That's why if we convert ReturnType incompatibility to WeakIncompatible
(which should have been called CheckingIncompatible), then expect-actual
matching model becomes consistent.
We will also be able to get rid of unnecessary
FirActualCallableDeclarationChecker. Because it won't be necessary.
Return types will be checked by common logic of expect-actual "checker"
Motivation: I'm going to drop NonPrivateCallableAdded (KT-62655) in the
next commits. But I don't want to change the existing logic when I drop
it. That's why I have to introduce the "Unknown" case
This includes checking of annotatins set on:
- value parameter types
- type parameter bound types
- extension functions receiver types
- function return types
- class super types
Fix in `defaultParams_inheritanceByDelegation_positive.kt`
is needed because of problem in resolution of implicit return types
(KT-62064), which leads to crash in annotation checker, because it
expects resolved return type.
MR: KT-MR-12245
^KT-60671 Fixed
The main reason of this commit is the fact that it makes no sense
to create type checker forks in case of two or more types which equal
each other.
Also, this commit fixes the test taken from KT-59514
(see interconnectedGenerics.kt test changed in this commit).
In this particular case we have a subType of C.WithL<Pr!, En<Pr>!>,
and a superType of R<T> with a superType constructor R.
In findCorrespondingSupertypes we get *two* similar supertypes here,
both have a string representation of:
R<Il<@EnhancedNullability En<Pr>!>!>.
If we create two forks because of it, we get NEW_INFERENCE_ERROR
with the following subtyping violation:
Il<@EnhancedNullability En<Pr>!>! <: En<Pr>!.
NEW_INFERENCE_ERROR happens because we make a redundant fork in that case,
but the forks should still work despite it (see KT-62333).
These two types appear due to the content of FirCorrespondingSupertypeCache.
For a key C.WithL and a superType R it stores the following pair of supertypes:
- R<Il<@EnhancedNullability S>!>
- R<Il<(@EnhancedNullability S & Any, @EnhancedNullability S?)>!>
After substitution of S to En<Pr>! they become similar.
NB: if we change jspecify severity level from strict to warn,
then 'R<Il<(S & Any, S?)>!>' is the only remaining supertype,
and @EnhancedNullability annotation is no more in use.
The type hierarchy in this example looks like:
WithL<T, S> <: CanWithB<T, S>, R.F<S, Il<S>>
CanWithB<T, S> <: R.F<S, Il<S>>
R.F<S, Il<S>> <: R<Il<S>>
So R is reachable by two different ways, via CanWithB and directly via R.F.
#KT-59514 Fixed
This is needed because in order to figure out which declarations are
visible from anonymous objects in terms of overridability (see
`FirVisibilityChecker.isVisibleForOverriding`), we need to get the
package name of that anonymous object, because there's package-private
visibility on JVM.
#KT-62017 Fixed
There is IDE quick fix which suggests to copy mismatched annotation
from `expect` to `actual` (see KTIJ-26633). It needs to find
`actual` PsiElement where to add annotation. Before previous commit, it
was easy - just get source of `Incompatibility.actualSymbol`.
After previous commit, the problem might be in value parameter, while
`actualSymbol` would contain function symbol. This is solved by adding
new field `Incompatibility.actualAnnotationTargetElement`.
`SourceElementMarker` introduced, because it's needed to be used in
abstract checker. Existing `DeclarationSymbolMarker` doesn't fit
because in next PR for this issue annotations set on types will be reported,
and types are not declarations.
^KT-60671
In this commit we begin counting a catch parameter as
both a local variable and a value parameter for the purpose
of annotation targeting.
#KT-61691 Fixed
There is a corresponding example inside the stdlib,
see `kotlin.text.startsWith`.
JVM and common counterpart are weakly-compatible
as the actual declaration has default arguments,
which results in `ExpectActualCompatibility.Incompatible.ActualFunctionWithDefaultParameters`
This commit allows such cases.
^KT-61732 fixed
@ImplicitlyActualizedByJvmDeclaration is the only one
OptionalExpectation annotation which works correctly when set only on
`expect`. All other (like @JvmName, @JsName) - not, so warning for them
must be reported.
^KT-61725 Fixed
In scope of: KT-22841
Review: https://jetbrains.team/p/kt/reviews/11867/timeline
Reduce complexity by reusing "expect-actual matcher" (namely
`AbstractExpectActualCompatibilityChecker.getCallablesCompatibility`)
The current solution has worse algorithmic complexity. Previously it was
O(n) in the best case, where `n` is a number of members. Now, it's
O(m^2), where `m` is number of members in one overload group. But we
prefer to have worse complexity but reuse expect-actual matcher, number
of elements in one overload group shall not be big on real world
examples.
The previous logic was non-trivial because it compared types with with
double comparison in `equals`.
If some function is not fake-override, then its type should be just
default type of containing class
For fake overrides the default type calculated in the following way:
1. Find first overridden function, which is not fake override
2. Take its containing class
3. Find supertype of current containing class with type constructor of
class from step 2
^KT-60252 Fixed
Review: https://jetbrains.team/p/kt/reviews/11039/timeline
For StrongIncompatible `actual` declaration is considered as overload
and error reports on expected declaration. For WeakIncompatible the
error is reported straight away
Before the refactoring `areCompatibleClassScopes` returned just
`Incompatible`. It is bad because StrongIncompatible isn't possible for
classes (classes can't be overloaded). Now all class incompatibilities
are weak.
The commit has a minor impact on observable behavior (cases where we
reported the compilation problems are still reported but on another
elements):
- We no longer report type parameter class incompatibilities on expect
declaration, we report them only on actuals (it happened because all
WeakIncompatible are reported only on actuals)
- In a sense, Java implicit actualization was the only way to "overload"
classes (it would be a redeclaration compilation problem, so it
doesn't count as a valid "overload"). And since type parameters
incompatibility was StrongIncompatible for classes, we counted them as
"overloads" and didn't report incompatibility problems on Kotlin
class. Now we do report. (see
implicitJavaActualization_multipleActuals)
Review: https://jetbrains.team/p/kt/reviews/11039/timeline
Extract main logic of `areCompatibleCallables` into two functions:
`areStrongIncompatibleCallables` and `areWeakIncompatibleCallables`.
The main point is that `areStrongIncompatibleCallables` &
`areWeakIncompatibleCallables` have very specific return types.
This commit doesn't change any logic. The commit makes the API more
type-safe ensuring that bugs like in previous commit (KT-60902) won't
happen again
^KT-59665 Fixed
Review: https://jetbrains.team/p/kt/reviews/11039/timeline
It's better to have this logic in common place
(AbstractExpectActualCompatibilityChecker) to avoid missing compilation
errors in the future
This commit fixes:
1. Missing compilation error for actual function with default arguments
for 'actual typealias' KT-59665
2. Missing compilation error for actual function with default arguments
for actual fake-override KT-59665
Alternative solution for KT-59665 is to create a special checker.
"incompatibility" vs "special checker":
Arguments for common incompatibility:
- What if we had a rule that expect and actual default params must
match? If so then it certainly would be an incompatibility.
- Technically, we do the matching of expect and actual params (because
we allow default params in common ancestors of expect and actual
declarations).
- It's hard to check that the actual definition doesn't use default
params because `ExpectedActualResolver.findActualForExpected` filters
out fake-overrides and doesn't return them. It's not clear logic for
me, that I'm afraid to touch.
implicitActualFakeOverride_AbstractMap.kt test breaks if you drop this
weird logic
- WEAK incompatibilities can be considered as "checkers". So it doesn't
matter how it's implemented, as a "incompatibility" or a "checker"
Arguments against common incompatibility:
- Although we match expect and actual declarations to allow default
params in common ancestors of expect and actual declarations, it's
still can be considered that we check that the actual declaration
doesn't have default params. And it doesn't feel right that we check
correctness of the actual declaration in expect-actual matcher.
- ~~It may change the rules of expect actual matching~~ (It's not true,
because ActualFunctionWithDefaultParameters is declared as WEAK
incompatibility)
Vladimir Sukharev