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)