This commit doesn't change behaviour of any inference algorithm, it
introduces opportunity to switch constraint system that is used for
overload resolution and fix problematic cases by changing one enum
entry.
Due to fundamental changes, there are cases where a new inference
algorithm reports overload resolution ambiguity errors (#KT-31670,
#KT-31758), which is correct from its point of view. However, this is
a breaking change and to really make it, we should be very confident
and have enough motivation for it, therefore, we don't change behavior
now in order to collect more examples (if there are any). And if we
find a lot of erroneous examples, we'll be able to change the behavior
quite simply
It's enough to have at least one good constraint.
Note that the whole algorithm can be a bit more general:
we could check also Out<T>, In<T> and verify that T has good only
lower constraint or upper constraint, but there are questions for
types like Inv<Out<T>>, where T should have lower and upper constraints
#KT-31514 Fixed
There is added a new service named `SubstitutingScopeProvider`, that
provides factory that creates captured types and approximator for them.
In OI they are the same as before commit, for NI they are empty, because
that approximation interferes with NI algorithm
That service is injected into function descriptors and property descriptors
and used for creating `SubstitutingScope` with correct services
Also there is changed time when we approximate captured types in NI
(after all call checkers)
#KT-25290 Fixed
Mostly, these optimisations are picked from the old inference.
Also, remove exponential complexity for flexible types in approximation,
note that more correct fix for this would be to introduce new types
that corresponds just to platform types to avoid nullability problems,
but due to complexity it will be done later
#KT-31415 Fixed
Also that commit removes usages of builtins inside
effect system and starts refactoring of functor
composition via composition instead of inheritance.
There are some changes in testdata related to inference of recursive
functions with implicit return types.
After this commit they all are marked as unresolved. It happens because
those functions have DeferredType as return type, and computing this
type produces recursive exception, which provides “typechecker
recursive problem” diagnostic.
Before this commit, function call was completed successfully, because
call completer didn’t computed that type, and computation of DeferredType
were triggered only in `DataFlowAnalyzer.checkType`.
Now, effect system tries to compute that type while wrapping KotlinTypes
into ESTypes, and effect system itself is triggered in in call completer,
so, call completion doesn’t finish and function call is marked as unresolved.
#KT-31364
There was a silly bug: equal constraint is actually a lower and an upper
constraint, but we checked only presence of lower constraints.
Test is important as here we have one equal constraint and should
complete inner call `foo<Int>()` without propagating it to `bar` to
avoid using `NoInfer` annotation multiple times
There is an inconsistency between old and new inference for storing
receivers of resolved calls. In new inference, for captured types,
receiver will be changed and to preserve behavior of the old inference,
we use original one during important checks.
This is more a workaround than a solution and should be revisited.
#KT-31356 Fixed
#KT-29948 Fixed
#KT-31360 Fixed
Use KotlinBuiltIns.isString instead of equality with
KotlinBuiltIns.string, which is more portable across different module
configurations. Also use isSubtypeOf instead of
DescriptorUtils.isSubclass and thus get rid of an extra error on an
unresolved class in nativeAnnotationCheckers.kt
Mikhail Zarechenskiy