... as well as $SwitchMap and other synthetic classes generated by javac
or other JVM language compilers or runtimes.
Note that for Kotlin, all synthetic classes were already handled by the
subsequent check for `KotlinClassHeader.Kind.SYNTHETIC_CLASS`, but after
this change we won't call `ReflectKotlinClass.create` for those, which
is a minor optimization.
#KT-41373 Fixed
... for Kotlin-generated classes which do not correspond to a "class"
from the Kotlin language's point of view. For example, Kotlin lambdas,
file facade classes, multifile class facade/part classes, WhenMappings,
DefaultImpls. They can be distinguished from normal classes by the value
of `KotlinClassHeader.Kind` (which is the same as `Metadata.kind`).
Another theoretical option would be to throw exception at the point
where the `::class` expression is used, if the expression's type on the
left-hand side is a synthetic class. But we can't really do that since
it'll affect performance of most `<expression>::class` expressions.
So, construct a fake synthetic class instead, without any members except
equals/hashCode/toString, and without any non-trivial modifiers. It kind
of contradicts the general idea that kotlin-reflect presents anything
exactly the same as the compiler sees it, but arguably it's worth it to
avoid unexpected exceptions like in KT-41373.
In the newly added test, Java lambda check is muted but it should work
exactly the same as for Kotlin lambdas and other synthetic classes. It's
fixed in a subsequent commit.
#KT-41373 In Progress
Alexander Udalov