[FIR] Don't build redundant fake overrides for private members

The only case we may need fake override for private members is
a situation when class refers itself with different type arguments.
So in this commit we forbid such fake overrides when we can prove
that class does not refers itself here.

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt

@@ -206,7 +206,7 @@ class Fir2IrVisitor(
                         declarations += irFunction.setParentByParentStack().withFunction {
                             setFunctionContent(irFunction.descriptor, originalFunction, firOverriddenSymbol = baseSymbol)
                         }
-                    } else if (fakeOverrideMode != FakeOverrideMode.SUBSTITUTION) {
+                    } else if (fakeOverrideMode != FakeOverrideMode.SUBSTITUTION && originalFunction.visibility != Visibilities.PRIVATE) {
                         // Trivial fake override case
                         val fakeOverrideSymbol =
                             FirClassSubstitutionScope.createFakeOverrideFunction(session, originalFunction, functionSymbol)
@@ -234,7 +234,7 @@ class Fir2IrVisitor(
                         declarations += irProperty.setParentByParentStack().withProperty {
                             setPropertyContent(irProperty.descriptor, originalProperty, firOverriddenSymbol = baseSymbol)
                         }
-                    } else if (fakeOverrideMode != FakeOverrideMode.SUBSTITUTION) {
+                    } else if (fakeOverrideMode != FakeOverrideMode.SUBSTITUTION && originalProperty.visibility != Visibilities.PRIVATE) {
                         // Trivial fake override case
                         val fakeOverrideSymbol =
                             FirClassSubstitutionScope.createFakeOverrideProperty(session, originalProperty, propertySymbol)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/ScopeUtils.kt

@@ -33,7 +33,7 @@ fun ConeKotlinType.scope(useSiteSession: FirSession, scopeSession: ScopeSession)
                 else -> emptyMap()
             }
 
-            fir.scope(substitutorByMap(substitution), useSiteSession, scopeSession)
+            fir.scope(substitutorByMap(substitution), useSiteSession, scopeSession, skipPrivateMembers = false)
         }
         is ConeTypeParameterType -> {
             // TODO: support LibraryTypeParameterSymbol or get rid of it

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/SupertypeUtils.kt

@@ -94,9 +94,11 @@ fun ConeClassLikeType.wrapSubstitutionScopeIfNeed(
             // to determine parameter types properly (e.g. String, String instead of K, V)
             val javaTypeParameters = javaClass.typeParameters
             val javaSubstitution = createSubstitution(javaTypeParameters, typeArguments, session)
-            FirClassSubstitutionScope(session, useSiteMemberScope, builder, originalSubstitution + javaSubstitution)
+            FirClassSubstitutionScope(
+                session, useSiteMemberScope, builder, originalSubstitution + javaSubstitution, skipPrivateMembers = true
+            )
         } else {
-            FirClassSubstitutionScope(session, useSiteMemberScope, builder, originalSubstitution)
+            FirClassSubstitutionScope(session, useSiteMemberScope, builder, originalSubstitution, skipPrivateMembers = true)
         }
     }
 }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/scopes/KotlinScopeProvider.kt

@@ -47,7 +47,10 @@ class KotlinScopeProvider(
                     if (useSiteSuperType is ConeClassErrorType) return@mapNotNull null
                     val symbol = useSiteSuperType.lookupTag.toSymbol(useSiteSession)
                     if (symbol is FirRegularClassSymbol) {
-                        symbol.fir.scope(substitutor(symbol, useSiteSuperType, useSiteSession), useSiteSession, scopeSession)
+                        symbol.fir.scope(
+                            substitutor(symbol, useSiteSuperType, useSiteSession),
+                            useSiteSession, scopeSession, skipPrivateMembers = true
+                        )
                     } else {
                         null
                     }
@@ -80,10 +83,15 @@ class KotlinScopeProvider(
 data class ConeSubstitutionScopeKey(val substitutor: ConeSubstitutor) : ScopeSessionKey<FirClass<*>, FirClassSubstitutionScope>()
 
 fun FirClass<*>.unsubstitutedScope(useSiteSession: FirSession, scopeSession: ScopeSession): FirScope {
-    return scope(ConeSubstitutor.Empty, useSiteSession, scopeSession)
+    return scopeProvider.getUseSiteMemberScope(this, useSiteSession, scopeSession)
 }
 
-fun FirClass<*>.scope(substitutor: ConeSubstitutor, useSiteSession: FirSession, scopeSession: ScopeSession): FirScope {
+internal fun FirClass<*>.scope(
+    substitutor: ConeSubstitutor,
+    useSiteSession: FirSession,
+    scopeSession: ScopeSession,
+    skipPrivateMembers: Boolean
+): FirScope {
     val basicScope = scopeProvider.getUseSiteMemberScope(
         this, useSiteSession, scopeSession
     )
@@ -92,6 +100,6 @@ fun FirClass<*>.scope(substitutor: ConeSubstitutor, useSiteSession: FirSession,
     return scopeSession.getOrBuild(
         this, ConeSubstitutionScopeKey(substitutor)
     ) {
-        FirClassSubstitutionScope(useSiteSession, basicScope, scopeSession, substitutor)
+        FirClassSubstitutionScope(useSiteSession, basicScope, scopeSession, substitutor, skipPrivateMembers)
     }
 }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/scopes/impl/FirClassSubstitutionScope.kt

@@ -5,11 +5,9 @@
 
 package org.jetbrains.kotlin.fir.scopes.impl
 
+import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.fir.FirSession
-import org.jetbrains.kotlin.fir.declarations.FirField
+import org.jetbrains.kotlin.fir.declarations.*
-import org.jetbrains.kotlin.fir.declarations.FirProperty
-import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
-import org.jetbrains.kotlin.fir.declarations.FirTypeParameter
 import org.jetbrains.kotlin.fir.declarations.builder.*
 import org.jetbrains.kotlin.fir.declarations.synthetic.FirSyntheticProperty
 import org.jetbrains.kotlin.fir.declarations.synthetic.buildSyntheticProperty
@@ -33,7 +31,8 @@ class FirClassSubstitutionScope(
     private val session: FirSession,
     private val useSiteMemberScope: FirScope,
     scopeSession: ScopeSession,
-    private val substitutor: ConeSubstitutor
+    private val substitutor: ConeSubstitutor,
+    private val skipPrivateMembers: Boolean
 ) : FirScope() {
 
     private val fakeOverrideFunctions = mutableMapOf<FirFunctionSymbol<*>, FirFunctionSymbol<*>>()
@@ -43,8 +42,9 @@ class FirClassSubstitutionScope(
 
     constructor(
         session: FirSession, useSiteMemberScope: FirScope, scopeSession: ScopeSession,
-        substitution: Map<FirTypeParameterSymbol, ConeKotlinType>
+        substitution: Map<FirTypeParameterSymbol, ConeKotlinType>,
-    ) : this(session, useSiteMemberScope, scopeSession, substitutorByMap(substitution))
+        skipPrivateMembers: Boolean
+    ) : this(session, useSiteMemberScope, scopeSession, substitutorByMap(substitution), skipPrivateMembers)
 
     override fun processFunctionsByName(name: Name, processor: (FirFunctionSymbol<*>) -> Unit) {
         useSiteMemberScope.processFunctionsByName(name) process@{ original ->
@@ -101,6 +101,7 @@ class FirClassSubstitutionScope(
             is FirConstructorSymbol -> return original
             else -> throw AssertionError("Should not be here")
         }
+        if (skipPrivateMembers && member.visibility == Visibilities.PRIVATE) return original
 
         val (newTypeParameters, newSubstitutor) = createNewTypeParametersAndSubstitutor(member)
 
@@ -170,6 +171,7 @@ class FirClassSubstitutionScope(
     private fun createFakeOverrideProperty(original: FirPropertySymbol): FirPropertySymbol {
         if (substitutor == ConeSubstitutor.Empty) return original
         val member = original.fir
+        if (skipPrivateMembers && member.visibility == Visibilities.PRIVATE) return original
 
         val receiverType = member.receiverTypeRef?.coneTypeUnsafe<ConeKotlinType>()
         val newReceiverType = receiverType?.substitute()
@@ -187,6 +189,7 @@ class FirClassSubstitutionScope(
     private fun createFakeOverrideField(original: FirFieldSymbol): FirFieldSymbol {
         if (substitutor == ConeSubstitutor.Empty) return original
         val member = original.fir
+        if (skipPrivateMembers && member.visibility == Visibilities.PRIVATE) return original
 
         val returnType = typeCalculator.tryCalculateReturnType(member).type
         val newReturnType = returnType.substitute() ?: return original
@@ -197,6 +200,7 @@ class FirClassSubstitutionScope(
     private fun createFakeOverrideAccessor(original: FirAccessorSymbol): FirAccessorSymbol {
         if (substitutor == ConeSubstitutor.Empty) return original
         val member = original.fir as FirSyntheticProperty
+        if (skipPrivateMembers && member.visibility == Visibilities.PRIVATE) return original
 
         val returnType = typeCalculator.tryCalculateReturnType(member).type
         val newReturnType = returnType.substitute()

compiler/testData/codegen/box/classes/kt1134.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // TODO: Enable when JS backend supports Java class library
 // TARGET_BACKEND: JVM
 public class SomeClass() : java.lang.Object() {

compiler/testData/codegen/box/jvm8/defaults/privateDefaultFromDefaultImpl.kt

@@ -1,5 +1,4 @@
 // !JVM_DEFAULT_MODE: enable
-// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 // JVM_TARGET: 1.8
 // WITH_RUNTIME

compiler/testData/codegen/box/traits/noPrivateDelegation.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // IGNORE_BACKEND: JS_IR
 // TODO: muted automatically, investigate should it be ran for JS or not
 // IGNORE_BACKEND: JS, NATIVE

compiler/testData/codegen/box/traits/syntheticAccessor.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 var result = "fail"
 
 interface B {

compiler/testData/codegen/box/typealias/kt15109.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 open class A(private val s: String = "") {
     fun foo() = s
 }

compiler/testData/ir/irText/classes/fakeOverridesForJavaStaticMembers.fir.txt

@@ -17,10 +17,6 @@ FILE fqName:<root> fileName:/fakeOverridesForJavaStaticMembers.kt
       overridden:
         public/*package*/ open fun packagePrivateStaticMethod (): kotlin.Unit declared in a.Base
       $this: VALUE_PARAMETER name:<this> type:a.Base
-    FUN FAKE_OVERRIDE name:privateStaticMethod visibility:private modality:OPEN <> ($this:a.Base) returnType:kotlin.Unit [fake_override]
-      overridden:
-        private open fun privateStaticMethod (): kotlin.Unit declared in a.Base
-      $this: VALUE_PARAMETER name:<this> type:a.Base
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any