Even though SO may not be correct
overrides sometimes, it feels more
natural to treat fake overrides as...
well, "overrides". And without it
we'd need to make the code in
`FirOverrideChecker` less intuitive.
Previously, there was a contract that each callable symbol in the chain
of `processDirectOverriddenWithBaseScope` will be unique. And if some
symbol is accessible from multiple scopes, then only last of them will
be returned as a component of `MemberWithScope`
But after the change from previous commit, we don't have this contract anymore.
Which means that we may meet the same symbol during processing hierarchy
of overridden functions (but with different base scopes)
So if some code utilizes `process...Overridden...WithBaseScope` functions
it should consider that the same symbol may be obtained several times
^KT-63738 Fixed
This big refactoring is needed to cleanup building of overrides
mappings and prevent creating redundant intersection overrides in
cases when there is no need in them:
```kotlin
interface A {
fun foo()
}
interface B {
fun foo()
}
interface C : A, B {
override fun foo()
}
```
Before this refactoring there was next override tree:
C.foo
intersection override (A.foo, B.foo)
A.foo
B.foo
Also this commit fixes special mapping of overrides in jvm scopes
for declarations which have kotlin builtins in supertypes with
special java mapping rules (collections, for example)
Nikolay Lunyak