Result of the `checkNotNull` calls should always be a non-nullable
values.
The simplest idea how to acheive it is adding not-nullable Any bound
to the type parameter declaration.
Existing comment stating about impossibility of such bound seems to be
not 100% correct because it doesn't take into account presence of
definitely-non-nullable X & Any types that allow described case with
nullable generic.
^KT-55804 Fixed
fix checking for intersection types in CheckIncompatibleTypeVariableUpperBounds
we need this resolve, because getEmptyIntersectionTypeKind under
the hood uses org.jetbrains.kotlin.resolve.checkers.EmptyIntersectionTypeChecker.computeEmptyIntersectionEmptiness
which uses computeByHavingCommonSubtype where we have
isFinalClassConstructor() call, so we need to resolve to STATUS phase
to get the correct modality
^KT-56543
The compiler should only report diagnostics for
comparisons over builtins and identity-less types,
other incompatibilities should be reported
via inspections.
It's ok that in `equalityChecksOnIntegerTypes`
instead of `EQUALITY_NOT_APPLICABLE_WARNING` we get
`EQUALITY_NOT_APPLICABLE`, because
`ProperEqualityChecksInBuilderInferenceCalls`
is already active by default.
This change also replaces the notion of a representative superclass
with the least upper bound.
This makes complex types like
intersection/flexible transparent to
RULES1-based compatibility checks.
One way to look at it is to think
that this is an automatic way of handling
type parameters: automatic picking of
"interesting" bounds, and checking them against one another.
Note that `TypeIntersector.intersectTypes`
for `Int` and `T` where `T` is a type parameter
may return both `{Int & T}` or `null`
depending on `T`-s bounds. At the same time,
for type parameters `T` and `K` it will
always return `{T & K}`.
`ConeTypeIntersector.intersectTypes`, on the
other hand, will always return `{Int & T}`
irrespectively of the bounds. Meaning, the two
intersectors differ in corner cases.
`lowerBoundIfFlexible` call in `isLiterallyTypeParameter` is backed by
the `equalityOfFlexibleTypeParameters` test.
^KT-35134 #fixed-in-k2
^KT-22499 #fixed-in-k2
^KT-46383 #fixed-in-k2
The only case when behavior is change is described at
computeNonTrivialTypeArgumentForScopeSubstitutor
The idea is to avoid depending on the presence of @UnsafeVariance
and instead approximate captured types in covariant argument positions
before building substitution scopes
It's correct because for Captured(*) <: Supertype,
Out<Captured(*)> <: Out<Supertype> and when we've got @UnsafeVariance
value parameters at Out, it's ok to allow passing Supertype there.
^KT-57602 Fixed
^KT-54894 Fixed
Note: here we set sinceVersion = null for this feature.
However, we plan in 1.9.* - 2.0 time frame to solve KT-56377
and to enable this feature in 2.0, the latest in 2.1.
This change allows to revert adding `WITH_STDLIB` directive
to tests which happened at `a9343aeb`.
Co-authored-by: Alexander Udalov <Alexander.Udalov@jetbrains.com>
The job is already done at CheckExtensionReceiver resolution stage
And repeating it might only lead to incorrect errors caused by
double-capture of receiver type that leads to contradiction because
in previous commit we started assuming different capture instantiations
as different types.
This is mostly a revert of 2f61a2f56f
There, we erroneously assumed that we may take captured types as equal
if they are based on the same-typed projections.
Each instance of capturing defines its own captured type,
that should not be equal to any other type captured in other place.
Initial motivation was brought by FP Ultimate, where a piece of code
from the new test was found that started working differently after
recent changes.
The most obvious consequence is the change in addAllProjection.fir.kt:
one cannot use an instance as an argument when expected type
is captured type based on the same instance.
Otherwise, it would lead to CCE if we allowed to put arbitrary charsequences
to the list that initially was a MutableList<String>
All other test data changes (but addAllProjection.fir.kt and differentCapturedTypes.kt)
are irrelevant and will be fixed in the subsequent commits
Namely, do not choose `Nothing?` result type when fixing a variable
that has other constraints besides the ones that came from
the relevant type parameter's upper bounds.
See more details in KT-55691.
In K1, the case from specialCallWithMaterializeAndExpectedType.kt
was working (inferred to String?) just because the branches
were analyzed independently with `String?` expected type.
This change became necessary after the previous commit when we united
inference subsystems for if/when branches (see motivation there).
NB: For K1, the behavior is left the same, but the code
was refactored a bit.
^KT-55691 Fixed
^KT-56448 Fixed
Otherwise, it leads to branches inference run fully independent,
while there are cases when it's necessary to flow type information from
one of the branch to another (see the new test).
NB. In K1, it worked differently: if branches were inferred altogether
only for Any/Any? expect types (otherwise they're analyzed independently)
See foo2/foo4 in the test.
To avoid breaking change we need to support foo1/foo3, but we're trying
not to have some special rule for Any, so we've got a new resolution mode
that provides expect type, but doesn't require full completion.
^KT-45989 Fixed
^KT-56563 Fixed
^KT-54709 Related
For change in specialCallWithMaterializeAndExpectedType.kt
At first, see at KT-36776
Long time ago, it's been decided that if/when resolution
should look similar to similar "select()" calls,
but it's a breaking change (see KT-36776), and we were ready for that back then.
But then, there were too many broken cases found, thus we reverted it at
100a6f70ca
But probably, it would be better to try to infer `String?`
instead of `Nothing?` (see next commits)
Note that change in specialCallWithMaterializeAndExpectedType.kt
will be addressed in later commits, too
When expected type is known, use it as expected type for branch bodies.
While it indeed becomes different from the usual select call resolution,
where expected type is applied only after completion starts,
it helps to support, e.g. callable references resolution just as powerful
as it was in K1.
Also, in some cases where diagnostics have been changed, they become
a bit more helpful since they are reported closer
to the problematic places
cannotCastToFunction.kt test has been removed because it relied
on the case erroneously supported by the hack removed from
the FirCallResolver in this commit.
^KT-45989 Fixed
^KT-55936 Fixed
^KT-56445 Fixed
^KT-54709 Related
^KT-55931 Related
Some of the changed tests may duplicate other existing diagnostics,
but that should not be reason not to report them at all.
There might be another job to be done to avoid diagnostic duplications
For example, NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER
It became especially relevant after 0e84bf2053
that together with later commits bring a lot of unnecessary
NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER diagnostic
Apparently if you add an empty line at the start of the FIR file, that's
not enough of a difference for the test suite to complain about, but
enough for it to not add the FIR_IDENTICAL directive...
While it is theoretically useful to know that `{ while(true) {} }`
returns Nothing, CFG node deadness is not precise enough to do that: if
the entire lambda is dead, it's no longer possible to find out whether
the loop is terminating. Besides, `while (true)` and `if (true)` are
pretty much the only constructs like that anyway.
Note that this commit does not affect resolution for lambdas that end in
a Nothing-returning expression, e.g. `throw`.
* `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
- If too few or too many type arguments were provided, they were all
thrown away in `TypeArgumentMapping`,
`FirCallCompletionResultsWriterTransformer`, and `KtFirCallResolver`.
The fix handles type arguments of the wrong arity more gracefully.
- Note for `TypeArgumentMapping`: Excess type arguments are not needed
for candidate resolution. Excess type arguments are still resolved
due to the handling in `FirCallCompletionResultsWriterTransformer`.
- Post-processing in `AllCandidatesResolver`: When all candidates are
resolved in `AllCandidatesResolver.getAllCandidates`, the function
builds a FIR file. During that resolution, the
`generic<String, String>` call (in example
`functionCallWithTooFewTypeArguments.kt`) is correctly marked as
inapplicable, but the missing type argument is inferred as an error
type. `firFile` then contains a function call
`generic<String, String, ERROR>` instead of `generic<String, String>`.
This call is still marked as inapplicable. Despite that, the
*subsequent* resolution by
`bodyResolveComponents.callResolve.collectAllCandidates` disregards
the call's inapplicability and resolves successfully into an
applicable candidate. This is because `CandidateFactory` doesn't make
any guarantees for already inapplicable calls. The fix adds
post-processing to `AllCandidatesResolver` to preserve candidate
inapplicability.
- Most tests that this commit changes had slightly different results due
to type arguments becoming resolvable.
- `wrongNumberOfTypeArguments.kt` and
`wrongNumberOfArgumentsInTypeAliasConstructor.kt`:
`ConeDiagnostic.toFirDiagnostics` prefers specific errors. Because
`ARGUMENT_TYPE_MISMATCH` is specific and `INAPPLICABLE_CANDIDATE` is
not, only the former is reported. I see no reason to pass an illegally
typed argument in either test, so the change reduces the errors to
`INAPPLICABLE_CANDIDATE`.
- `typeAliasSamAdapterConstructors2.fir.kt`: See KT-55007.
- Disable `mismatchTypeParameters` JS backend test due to its handling
of excess type arguments. See KT-55250.
^KT-54980 fixed
- LL FIR uses `ReturnTypeCalculatorWithJump` by default because it
cannot guarantee that the implicit types of non-local functions
referenced in a function `f` have been resolved during body resolve
of `f`.
- However, if `ReturnTypeCalculatorWithJump` encountered a local
function, it tried to resolve its return type even during body
resolve of that same local function. The fix delegates to
`ReturnTypeCalculatorForFullBodyResolve`, which should be used for
local declarations.
^KT-55327 fixed
^KT-55324 fixed
Incompatible supertypes check also don't provoke runtime problems
in most situations, because this check is also bound to type argument
conflict. Related to KT-54411
The situations with conflicting type arguments normally don't provoke
any runtime problems. Also, conflicts like A<T> VS A<SomeType> aren't
valid at all. Here we decided to remove them to avoid strange
and non-actionable warnings in user code.
#KT-54411 Fixed
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
Denis.Zharkov