[FIR] Reuse getNonSubsumedNonPhantomOverriddenSymbols

Just a small refactoring to avoid
duplicating comments.

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/scopes/JavaOverrideChecker.kt

@@ -29,7 +29,6 @@ import org.jetbrains.kotlin.fir.scopes.MemberWithBaseScope
 import org.jetbrains.kotlin.fir.scopes.ProcessorAction
 import org.jetbrains.kotlin.fir.scopes.impl.FirAbstractOverrideChecker
 import org.jetbrains.kotlin.fir.scopes.impl.chooseIntersectionVisibilityOrNull
-import org.jetbrains.kotlin.fir.scopes.impl.filterOutDuplicates
 import org.jetbrains.kotlin.fir.scopes.impl.isAbstract
 import org.jetbrains.kotlin.fir.scopes.jvm.computeJvmDescriptorRepresentation
 import org.jetbrains.kotlin.fir.scopes.processOverriddenFunctions
@@ -375,12 +374,7 @@ class JavaOverrideChecker internal constructor(
         extractedOverrides: Collection<MemberWithBaseScope<D>>,
         dispatchClassSymbol: FirRegularClassSymbol?,
     ): Visibility {
-        // It's crucial that we only unwrap phantom intersection overrides.
-        // See comments in the following tests for explanation:
-        // - intersectionWithMultipleDefaultsInJavaOverriddenByIntersectionInKotlin.kt
-        // - intersectionOverridesIntersection.kt
-        val overridesWithoutIntersections = extractedOverrides.flatMap { it.flattenPhantomIntersectionsRecursively() }
-        val nonSubsumed = overridesWithoutIntersections.nonSubsumed().filterOutDuplicates()
+        val nonSubsumed = extractedOverrides.getNonSubsumedNonPhantomOverriddenSymbols()
 
         // In Java it's OK to inherit multiple implementations of the same function
         // from the supertypes as long as there's an implementation from a class.

compiler/fir/providers/src/org/jetbrains/kotlin/fir/scopes/impl/FirOverrideUtils.kt

@@ -15,7 +15,6 @@ import org.jetbrains.kotlin.fir.scopes.*
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirNamedFunctionSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirPropertySymbol
-import org.jetbrains.kotlin.fir.unwrapSubstitutionOverrides
 import org.jetbrains.kotlin.name.StandardClassIds
 
 fun filterOutOverriddenFunctions(extractedOverridden: Collection<MemberWithBaseScope<FirNamedFunctionSymbol>>): Collection<MemberWithBaseScope<FirNamedFunctionSymbol>> {
@@ -92,11 +91,6 @@ val MemberWithBaseScope<FirCallableSymbol<*>>.isAbstract: Boolean
         return member.rawStatus.modality == Modality.ABSTRACT
     }
 
-fun <D : FirCallableSymbol<*>> List<MemberWithBaseScope<D>>.filterOutDuplicates(): List<MemberWithBaseScope<D>> {
-    val uniqueSymbols = mutableSetOf<FirCallableSymbol<*>>()
-    return filter { uniqueSymbols.add(it.member.fir.unwrapSubstitutionOverrides().symbol) }
-}
-
 fun <D : FirCallableSymbol<*>> findMaxVisibilityOrNull(
     extractedOverrides: Collection<MemberWithBaseScope<D>>
 ): Visibility? {

compiler/fir/providers/src/org/jetbrains/kotlin/fir/scopes/impl/FirStandardOverrideChecker.kt

@@ -166,12 +166,7 @@ class FirStandardOverrideChecker(private val session: FirSession) : FirAbstractO
         extractedOverrides: Collection<MemberWithBaseScope<D>>,
         dispatchClassSymbol: FirRegularClassSymbol?,
     ): Visibility {
-        // It's crucial that we only unwrap phantom intersection overrides.
-        // See comments in the following tests for explanation:
-        // - intersectionWithMultipleDefaultsInJavaOverriddenByIntersectionInKotlin.kt
-        // - intersectionOverridesIntersection.kt
-        val overridesWithoutIntersections = extractedOverrides.flatMap { it.flattenPhantomIntersectionsRecursively() }
-        val nonSubsumed = overridesWithoutIntersections.nonSubsumed().filterOutDuplicates()
+        val nonSubsumed = extractedOverrides.getNonSubsumedNonPhantomOverriddenSymbols()
         return chooseIntersectionVisibilityOrNull(nonSubsumed) ?: Visibilities.Unknown
     }
 }