FIR: Rework delegated scope

Now delegated members are generated just to declared scope

^KT-47413 In Progress

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/JavaScopeProvider.kt

@@ -91,7 +91,7 @@ class JavaScopeProvider(
                     lookupSuperTypes(regularClass, lookupInterfaces = true, deep = false, useSiteSession = useSiteSession)
 
             val superTypeScopes = superTypes.mapNotNull {
-                it.scopeForSupertype(useSiteSession, scopeSession, subClass = regularClass, declaredScope, delegateFields = null)
+                it.scopeForSupertype(useSiteSession, scopeSession, subClass = regularClass)
             }
 
             JavaClassUseSiteMemberScope(

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

@@ -10,19 +10,15 @@ import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.declarations.FirClass
 import org.jetbrains.kotlin.fir.declarations.FirField
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
-import org.jetbrains.kotlin.fir.declarations.FirResolvePhase
 import org.jetbrains.kotlin.fir.declarations.utils.isExpect
 import org.jetbrains.kotlin.fir.declarations.utils.isSynthetic
 import org.jetbrains.kotlin.fir.resolve.*
 import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutor
 import org.jetbrains.kotlin.fir.resolve.substitution.substitutorByMap
-import org.jetbrains.kotlin.fir.resolve.transformers.ensureResolved
 import org.jetbrains.kotlin.fir.scopes.impl.*
 import org.jetbrains.kotlin.fir.symbols.ConeClassLikeLookupTag
 import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
-import org.jetbrains.kotlin.fir.typeContext
 import org.jetbrains.kotlin.fir.types.*
-import org.jetbrains.kotlin.name.CallableId
 
 class FirKotlinScopeProvider(
     val declaredMemberScopeDecorator: (
@@ -39,13 +35,21 @@ class FirKotlinScopeProvider(
     ): FirTypeScope {
         return scopeSession.getOrBuild(klass.symbol, USE_SITE) {
             val declaredScope = useSiteSession.declaredMemberScope(klass)
-            val decoratedDeclaredMemberScope =
-                declaredMemberScopeDecorator(klass, declaredScope, useSiteSession, scopeSession)
 
             val delegateFields = klass.declarations.filterIsInstance<FirField>().filter { it.isSynthetic }
+
+            val decoratedDeclaredMemberScope =
+                declaredMemberScopeDecorator(klass, declaredScope, useSiteSession, scopeSession).let {
+                    if (delegateFields.isEmpty())
+                        it
+                    else
+                        FirNewDelegatedMemberScope(useSiteSession, scopeSession, klass, it, delegateFields)
+                }
+
+
             val scopes = lookupSuperTypes(klass, lookupInterfaces = true, deep = false, useSiteSession = useSiteSession)
                 .mapNotNull { useSiteSuperType ->
-                    useSiteSuperType.scopeForSupertype(useSiteSession, scopeSession, klass, decoratedDeclaredMemberScope, delegateFields)
+                    useSiteSuperType.scopeForSupertype(useSiteSession, scopeSession, klass)
                 }
             FirClassUseSiteMemberScope(
                 useSiteSession,
@@ -79,8 +83,6 @@ data class ConeSubstitutionScopeKey(
     val lookupTag: ConeClassLikeLookupTag, val isFromExpectClass: Boolean, val substitutor: ConeSubstitutor
 ) : ScopeSessionKey<FirClass, FirClassSubstitutionScope>()
 
-data class DelegatedMemberScopeKey(val callableId: CallableId) : ScopeSessionKey<FirField, FirDelegatedMemberScope>()
-
 fun FirClass.unsubstitutedScope(
     useSiteSession: FirSession,
     scopeSession: ScopeSession,
@@ -107,25 +109,19 @@ fun ConeKotlinType.scopeForSupertype(
     useSiteSession: FirSession,
     scopeSession: ScopeSession,
     subClass: FirClass,
-    declaredMemberScope: FirScope,
-    delegateFields: List<FirField>?,
 ): FirTypeScope? {
     if (this !is ConeClassLikeType) return null
     if (this is ConeClassErrorType) return null
     val symbol = lookupTag.toSymbol(useSiteSession)
     return if (symbol is FirRegularClassSymbol) {
-        val delegateField = delegateFields?.find {
-            it.ensureResolved(FirResolvePhase.TYPES, useSiteSession)
-            useSiteSession.typeContext.equalTypes(it.returnTypeRef.coneType, this)
-        }
-        symbol.fir.scopeForSupertype(
+        symbol.fir.scopeForClassImpl(
             substitutor(symbol, this, useSiteSession),
-            useSiteSession, scopeSession, delegateField,
-            subClass = subClass,
-            declaredMemberScope
-        ).let {
-            it as? FirTypeScope ?: error("$it is expected to be FirOverrideAwareScope")
-        }
+            useSiteSession,
+            scopeSession,
+            skipPrivateMembers = true,
+            classFirDispatchReceiver = subClass,
+            isFromExpectClass = (subClass as? FirRegularClass)?.isExpect == true
+        )
     } else {
         null
     }
@@ -137,30 +133,6 @@ private fun substitutor(symbol: FirRegularClassSymbol, type: ConeClassLikeType,
     return substitutorByMap(originalSubstitution, useSiteSession)
 }
 
-fun FirClass.scopeForSupertype(
-    substitutor: ConeSubstitutor,
-    useSiteSession: FirSession,
-    scopeSession: ScopeSession,
-    delegateField: FirField?,
-    subClass: FirClass,
-    declaredMemberScope: FirScope,
-): FirTypeScope = scopeForClassImpl(
-    substitutor,
-    useSiteSession,
-    scopeSession,
-    skipPrivateMembers = true,
-    classFirDispatchReceiver = subClass,
-    isFromExpectClass = (subClass as? FirRegularClass)?.isExpect == true
-).let {
-    if (delegateField != null) {
-        scopeSession.getOrBuild(delegateField, DelegatedMemberScopeKey(delegateField.symbol.callableId)) {
-            FirDelegatedMemberScope(it, useSiteSession, subClass, delegateField, declaredMemberScope)
-        }
-    } else {
-        it
-    }
-}
-
 private fun FirClass.scopeForClassImpl(
     substitutor: ConeSubstitutor,
     useSiteSession: FirSession,
@@ -176,7 +148,7 @@ private fun FirClass.scopeForClassImpl(
         this, ConeSubstitutionScopeKey(classFirDispatchReceiver.symbol.toLookupTag(), isFromExpectClass, substitutor)
     ) {
         FirClassSubstitutionScope(
-            useSiteSession, basicScope,  substitutor, classFirDispatchReceiver.defaultType(),
+            useSiteSession, basicScope, substitutor, classFirDispatchReceiver.defaultType(),
             skipPrivateMembers, makeExpect = isFromExpectClass
         )
     }

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

@@ -0,0 +1,170 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.fir.scopes.impl
+
+import org.jetbrains.kotlin.descriptors.Modality
+import org.jetbrains.kotlin.descriptors.Visibilities
+import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.declarations.*
+import org.jetbrains.kotlin.fir.resolve.ScopeSession
+import org.jetbrains.kotlin.fir.resolve.defaultType
+import org.jetbrains.kotlin.fir.resolve.scope
+import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutor
+import org.jetbrains.kotlin.fir.resolve.transformers.ensureResolved
+import org.jetbrains.kotlin.fir.scopes.*
+import org.jetbrains.kotlin.fir.symbols.impl.*
+import org.jetbrains.kotlin.fir.types.coneType
+import org.jetbrains.kotlin.name.Name
+
+class FirNewDelegatedMemberScope(
+    private val session: FirSession,
+    private val scopeSession: ScopeSession,
+    private val containingClass: FirClass<*>,
+    private val declaredMemberScope: FirScope,
+    private val delegateFields: List<FirField>,
+) : FirScope() {
+    private val dispatchReceiverType = containingClass.defaultType()
+    private val overrideChecker = FirStandardOverrideChecker(session)
+
+    override fun processFunctionsByName(name: Name, processor: (FirNamedFunctionSymbol) -> Unit) {
+        declaredMemberScope.processFunctionsByName(name, processor)
+        val result = mutableListOf<FirNamedFunctionSymbol>()
+
+        for (delegateField in delegateFields) {
+            processFunctionsFromSpecificField(delegateField, name, result)
+        }
+
+        result.forEach(processor)
+    }
+
+    private fun buildScope(delegateField: FirField): FirTypeScope? {
+        delegateField.ensureResolved(FirResolvePhase.TYPES, session)
+        return delegateField.returnTypeRef.coneType.scope(session, scopeSession, FakeOverrideTypeCalculator.DoNothing)
+    }
+
+    private fun processFunctionsFromSpecificField(
+        delegateField: FirField,
+        name: Name,
+        result: MutableList<FirNamedFunctionSymbol>
+    ) {
+        val scope = buildScope(delegateField) ?: return
+
+        scope.processFunctionsByName(name) processor@{ functionSymbol ->
+            val original = functionSymbol.fir
+            // KT-6014: If the original is abstract, we still need a delegation
+            // For example,
+            //   interface IBase { override fun toString(): String }
+            //   object BaseImpl : IBase { override fun toString(): String = ... }
+            //   class Test : IBase by BaseImpl
+            if (original.isPublicInAny() && original.modality != Modality.ABSTRACT) {
+                return@processor
+            }
+
+            if (original.modality == Modality.FINAL || original.visibility == Visibilities.Private) {
+                return@processor
+            }
+
+            if (declaredMemberScope.getFunctions(name).any { overrideChecker.isOverriddenFunction(it.fir, original) }) {
+                return@processor
+            }
+
+            result.firstOrNull {
+                overrideChecker.isOverriddenFunction(it.fir, original)
+            }?.let {
+                it.fir.multipleDelegatesWithTheSameSignature = true
+                return@processor
+            }
+
+            val delegatedSymbol =
+                FirFakeOverrideGenerator.createCopyForFirFunction(
+                    FirNamedFunctionSymbol(
+                        functionSymbol.callableId,
+                    ),
+                    original,
+                    session,
+                    FirDeclarationOrigin.Delegated,
+                    newDispatchReceiverType = dispatchReceiverType,
+                    newModality = Modality.OPEN,
+                ).apply {
+                    delegatedWrapperData = DelegatedWrapperData(functionSymbol.fir, containingClass.symbol.toLookupTag(), delegateField)
+                }.symbol
+
+            result += delegatedSymbol
+        }
+    }
+
+    override fun processPropertiesByName(name: Name, processor: (FirVariableSymbol<*>) -> Unit) {
+        declaredMemberScope.processPropertiesByName(name, processor)
+
+        val result = mutableListOf<FirPropertySymbol>()
+        for (delegateField in delegateFields) {
+            processPropertiesFromSpecificField(delegateField, name, result)
+        }
+
+        result.forEach(processor)
+    }
+
+    override fun processClassifiersByNameWithSubstitution(name: Name, processor: (FirClassifierSymbol<*>, ConeSubstitutor) -> Unit) {
+        declaredMemberScope.processClassifiersByNameWithSubstitution(name, processor)
+    }
+
+    override fun processDeclaredConstructors(processor: (FirConstructorSymbol) -> Unit) {
+        declaredMemberScope.processDeclaredConstructors(processor)
+    }
+
+    private fun processPropertiesFromSpecificField(
+        delegateField: FirField,
+        name: Name,
+        result: MutableList<FirPropertySymbol>
+    ) {
+        val scope = buildScope(delegateField) ?: return
+
+        scope.processPropertiesByName(name) processor@{ propertySymbol ->
+            if (propertySymbol !is FirPropertySymbol) {
+                return@processor
+            }
+
+            val original = propertySymbol.fir
+
+            if (original.modality == Modality.FINAL || original.visibility == Visibilities.Private) {
+                return@processor
+            }
+
+            if (declaredMemberScope.getProperties(name)
+                    .any { it is FirPropertySymbol && overrideChecker.isOverriddenProperty(it.fir, original) }
+            ) {
+                return@processor
+            }
+
+
+            result.firstOrNull {
+                overrideChecker.isOverriddenProperty(it.fir, original)
+            }?.let {
+                it.fir.multipleDelegatesWithTheSameSignature = true
+                return@processor
+            }
+
+            val delegatedSymbol =
+                FirFakeOverrideGenerator.createCopyForFirProperty(
+                    FirPropertySymbol(
+                        propertySymbol.callableId
+                    ),
+                    original,
+                    session,
+                    FirDeclarationOrigin.Delegated,
+                    newModality = Modality.OPEN,
+                    newDispatchReceiverType = dispatchReceiverType,
+                ).apply {
+                    delegatedWrapperData = DelegatedWrapperData(propertySymbol.fir, containingClass.symbol.toLookupTag(), delegateField)
+                }.symbol
+            result += delegatedSymbol
+        }
+    }
+}
+
+private object MultipleDelegatesWithTheSameSignatureKey : FirDeclarationDataKey()
+
+var FirCallableDeclaration<*>.multipleDelegatesWithTheSameSignature: Boolean? by FirDeclarationDataRegistry.data(MultipleDelegatesWithTheSameSignatureKey)

compiler/testData/ir/irText/firProblems/DelegationAndInheritanceFromJava.fir.txt

@@ -8,7 +8,7 @@ FILE fqName:<root> fileName:/DelegationAndInheritanceFromJava.kt
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:Impl modality:FINAL visibility:public superTypes:[<root>.Foo.A; <root>.Foo.B]'
     FUN DELEGATED_MEMBER name:add visibility:public modality:OPEN <> ($this:<root>.Impl, element:@[FlexibleNullability] kotlin.String?) returnType:kotlin.Boolean
       overridden:
-        public abstract fun add (element: @[FlexibleNullability] kotlin.String?): kotlin.Boolean [fake_override] declared in <root>.Foo.B
+        public abstract fun add (element: @[FlexibleNullability] kotlin.String?): kotlin.Boolean [fake_override] declared in <root>.Foo.A
       $this: VALUE_PARAMETER name:<this> type:<root>.Impl
       VALUE_PARAMETER name:element index:0 type:@[FlexibleNullability] kotlin.String?
       BLOCK_BODY
@@ -19,7 +19,7 @@ FILE fqName:<root> fileName:/DelegationAndInheritanceFromJava.kt
             element: GET_VAR 'element: @[FlexibleNullability] kotlin.String? declared in <root>.Impl.add' type=@[FlexibleNullability] kotlin.String? origin=null
     FUN DELEGATED_MEMBER name:addAll visibility:public modality:OPEN <> ($this:<root>.Impl, elements:kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>) returnType:kotlin.Boolean
       overridden:
-        public abstract fun addAll (elements: kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>): kotlin.Boolean [fake_override] declared in <root>.Foo.B
+        public abstract fun addAll (elements: kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>): kotlin.Boolean [fake_override] declared in <root>.Foo.A
       $this: VALUE_PARAMETER name:<this> type:<root>.Impl
       VALUE_PARAMETER name:elements index:0 type:kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>
       BLOCK_BODY
@@ -39,7 +39,7 @@ FILE fqName:<root> fileName:/DelegationAndInheritanceFromJava.kt
             receiver: GET_VAR '<this>: <root>.Impl declared in <root>.Impl.clear' type=<root>.Impl origin=null
     FUN DELEGATED_MEMBER name:iterator visibility:public modality:OPEN <> ($this:<root>.Impl) returnType:kotlin.collections.MutableIterator<@[FlexibleNullability] kotlin.String?> [operator]
       overridden:
-        public abstract fun iterator (): kotlin.collections.MutableIterator<@[FlexibleNullability] kotlin.String?> [fake_override,operator] declared in <root>.Foo.B
+        public abstract fun iterator (): kotlin.collections.MutableIterator<@[FlexibleNullability] kotlin.String?> [fake_override,operator] declared in <root>.Foo.A
       $this: VALUE_PARAMETER name:<this> type:<root>.Impl
       BLOCK_BODY
         RETURN type=kotlin.Nothing from='public open fun iterator (): kotlin.collections.MutableIterator<@[FlexibleNullability] kotlin.String?> [operator] declared in <root>.Impl'
@@ -48,7 +48,7 @@ FILE fqName:<root> fileName:/DelegationAndInheritanceFromJava.kt
               receiver: GET_VAR '<this>: <root>.Impl declared in <root>.Impl.iterator' type=<root>.Impl origin=null
     FUN DELEGATED_MEMBER name:remove visibility:public modality:OPEN <> ($this:<root>.Impl, element:@[FlexibleNullability] kotlin.String?) returnType:kotlin.Boolean
       overridden:
-        public abstract fun remove (element: @[FlexibleNullability] kotlin.String?): kotlin.Boolean [fake_override] declared in <root>.Foo.B
+        public abstract fun remove (element: @[FlexibleNullability] kotlin.String?): kotlin.Boolean [fake_override] declared in <root>.Foo.A
       $this: VALUE_PARAMETER name:<this> type:<root>.Impl
       VALUE_PARAMETER name:element index:0 type:@[FlexibleNullability] kotlin.String?
       BLOCK_BODY
@@ -59,7 +59,7 @@ FILE fqName:<root> fileName:/DelegationAndInheritanceFromJava.kt
             element: GET_VAR 'element: @[FlexibleNullability] kotlin.String? declared in <root>.Impl.remove' type=@[FlexibleNullability] kotlin.String? origin=null
     FUN DELEGATED_MEMBER name:removeAll visibility:public modality:OPEN <> ($this:<root>.Impl, elements:kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>) returnType:kotlin.Boolean
       overridden:
-        public abstract fun removeAll (elements: kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>): kotlin.Boolean [fake_override] declared in <root>.Foo.B
+        public abstract fun removeAll (elements: kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>): kotlin.Boolean [fake_override] declared in <root>.Foo.A
       $this: VALUE_PARAMETER name:<this> type:<root>.Impl
       VALUE_PARAMETER name:elements index:0 type:kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>
       BLOCK_BODY
@@ -70,7 +70,7 @@ FILE fqName:<root> fileName:/DelegationAndInheritanceFromJava.kt
             elements: GET_VAR 'elements: kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?> declared in <root>.Impl.removeAll' type=kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?> origin=null
     FUN DELEGATED_MEMBER name:retainAll visibility:public modality:OPEN <> ($this:<root>.Impl, elements:kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>) returnType:kotlin.Boolean
       overridden:
-        public abstract fun retainAll (elements: kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>): kotlin.Boolean [fake_override] declared in <root>.Foo.B
+        public abstract fun retainAll (elements: kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>): kotlin.Boolean [fake_override] declared in <root>.Foo.A
       $this: VALUE_PARAMETER name:<this> type:<root>.Impl
       VALUE_PARAMETER name:elements index:0 type:kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>
       BLOCK_BODY
@@ -81,7 +81,7 @@ FILE fqName:<root> fileName:/DelegationAndInheritanceFromJava.kt
             elements: GET_VAR 'elements: kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?> declared in <root>.Impl.retainAll' type=kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?> origin=null
     FUN DELEGATED_MEMBER name:contains visibility:public modality:OPEN <> ($this:<root>.Impl, element:@[FlexibleNullability] kotlin.String?) returnType:kotlin.Boolean [operator]
       overridden:
-        public abstract fun contains (element: @[FlexibleNullability] kotlin.String?): kotlin.Boolean [fake_override,operator] declared in <root>.Foo.B
+        public abstract fun contains (element: @[FlexibleNullability] kotlin.String?): kotlin.Boolean [fake_override,operator] declared in <root>.Foo.A
       $this: VALUE_PARAMETER name:<this> type:<root>.Impl
       VALUE_PARAMETER name:element index:0 type:@[FlexibleNullability] kotlin.String?
       BLOCK_BODY
@@ -92,7 +92,7 @@ FILE fqName:<root> fileName:/DelegationAndInheritanceFromJava.kt
             element: GET_VAR 'element: @[FlexibleNullability] kotlin.String? declared in <root>.Impl.contains' type=@[FlexibleNullability] kotlin.String? origin=null
     FUN DELEGATED_MEMBER name:containsAll visibility:public modality:OPEN <> ($this:<root>.Impl, elements:kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>) returnType:kotlin.Boolean
       overridden:
-        public abstract fun containsAll (elements: kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>): kotlin.Boolean [fake_override] declared in <root>.Foo.B
+        public abstract fun containsAll (elements: kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>): kotlin.Boolean [fake_override] declared in <root>.Foo.A
       $this: VALUE_PARAMETER name:<this> type:<root>.Impl
       VALUE_PARAMETER name:elements index:0 type:kotlin.collections.Collection<@[FlexibleNullability] kotlin.String?>
       BLOCK_BODY