Use the same logic as for type constructors of classes, based on the
fully-qualified name of the classifier, with special cases for error
types and local declarations, with an additional check that the type
constructors' declaration descriptors are structurally equal via
`DescriptorEquivalenceForOverrides`. The latter is required because type
parameters of overloaded functions must be different, even though their
full FQ name is the same.
This (hopefully) has no effect for the compiler, but is useful for
kotlin-reflect where `KType.equals` runs the type checker on the
underlying `KotlinType` instances, which eventually ends up comparing
type constructors. Descriptors and types in kotlin-reflect are cached on
soft references, so they may be suddenly garbage-collected and
recomputed, and we want copies of the same type parameter to be equal to
each other.
This fixes flaky codegen tests which started to fail after migration to
the new test infrastructure, where tests are now run in parallel in the
same process, thus with higher memory pressure and more soft references
being GC'd:
* `codegen/box/reflection/types/createType/typeParameter.kt`
* `codegen/box/reflection/supertypes/genericSubstitution.kt`
Also, add a new test to check that we do the instanceof check in
overrides of `AbstractTypeConstructor.isSameClassifier`.
#KT-44850 Fixed
Alexander Udalov
4d9cffccf2