Implement fake override mapping for functions

Related to KT-29636

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirRenderer.kt

@@ -13,6 +13,7 @@ import org.jetbrains.kotlin.fir.expressions.*
 import org.jetbrains.kotlin.fir.expressions.impl.*
 import org.jetbrains.kotlin.fir.symbols.ConeClassLikeSymbol
 import org.jetbrains.kotlin.fir.symbols.ConeSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirFunctionSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirTypeParameterSymbol
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.impl.FirImplicitBuiltinType
@@ -697,7 +698,15 @@ class FirRenderer(builder: StringBuilder) : FirVisitorVoid() {
 
     override fun visitResolvedCallableReference(resolvedCallableReference: FirResolvedCallableReference) {
         print("R|")
+        val isFakeOverride = (resolvedCallableReference.callableSymbol as? FirFunctionSymbol)?.isFakeOverride == true
+
+        if (isFakeOverride) {
+            print("FakeOverride<")
+        }
         print(resolvedCallableReference.callableSymbol.callableId)
+        if (isFakeOverride) {
+            print(">")
+        }
         print("|")
     }
 

compiler/fir/tree/src/org/jetbrains/kotlin/fir/declarations/impl/FirAbstractCallableMember.kt

@@ -17,25 +17,47 @@ import org.jetbrains.kotlin.fir.types.FirType
 import org.jetbrains.kotlin.fir.visitors.FirTransformer
 import org.jetbrains.kotlin.name.Name
 
-abstract class FirAbstractCallableMember(
-    session: FirSession,
-    psi: PsiElement?,
-    final override val symbol: FirBasedSymbol<FirCallableMember>,
-    name: Name,
-    visibility: Visibility,
-    modality: Modality?,
-    isExpect: Boolean,
-    isActual: Boolean,
-    isOverride: Boolean,
-    final override var receiverType: FirType?,
-    final override var returnType: FirType
-) : FirAbstractMemberDeclaration(session, psi, name, visibility, modality, isExpect, isActual), FirCallableMember {
+abstract class FirAbstractCallableMember : FirAbstractMemberDeclaration, FirCallableMember {
 
-    init {
+    final override val symbol: FirBasedSymbol<FirCallableMember>
+    final override var receiverType: FirType?
+    final override var returnType: FirType
+
+    constructor(
+        session: FirSession,
+        psi: PsiElement?,
+        symbol: FirBasedSymbol<FirCallableMember>,
+        name: Name,
+        receiverType: FirType?,
+        returnType: FirType
+    ) : super(session, psi, name) {
+        this.symbol = symbol
         symbol.bind(this)
+        this.receiverType = receiverType
+        this.returnType = returnType
+    }
+
+    constructor(
+        session: FirSession,
+        psi: PsiElement?,
+        symbol: FirBasedSymbol<FirCallableMember>,
+        name: Name,
+        visibility: Visibility,
+        modality: Modality?,
+        isExpect: Boolean,
+        isActual: Boolean,
+        isOverride: Boolean,
+        receiverType: FirType?,
+        returnType: FirType
+    ) : super(session, psi, name, visibility, modality, isExpect, isActual) {
+        this.symbol = symbol
+        symbol.bind(this)
+        this.receiverType = receiverType
+        this.returnType = returnType
         status.isOverride = isOverride
     }
 
+
     override fun <D> transformChildren(transformer: FirTransformer<D>, data: D): FirElement {
         receiverType = receiverType?.transformSingle(transformer, data)
         returnType = returnType.transformSingle(transformer, data)

compiler/fir/tree/src/org/jetbrains/kotlin/fir/declarations/impl/FirAbstractMemberDeclaration.kt

@@ -20,23 +20,31 @@ import org.jetbrains.kotlin.name.Name
 abstract class FirAbstractMemberDeclaration(
     session: FirSession,
     psi: PsiElement?,
-    name: Name,
-    visibility: Visibility,
-    modality: Modality?,
-    isExpect: Boolean,
-    isActual: Boolean
+    name: Name
 ) : FirAbstractNamedAnnotatedDeclaration(session, psi, name), FirMemberDeclaration {
-    final override val typeParameters = mutableListOf<FirTypeParameter>()
-
-    final override var status = FirDeclarationStatusImpl(
-        session,
-        visibility,
-        modality
-    ).apply {
-        this.isExpect = isExpect
-        this.isActual = isActual
+    constructor(
+        session: FirSession,
+        psi: PsiElement?,
+        name: Name,
+        visibility: Visibility,
+        modality: Modality?,
+        isExpect: Boolean,
+        isActual: Boolean
+    ) : this(session, psi, name) {
+        this.status = FirDeclarationStatusImpl(
+            session,
+            visibility,
+            modality
+        ).apply {
+            this.isExpect = isExpect
+            this.isActual = isActual
+        }
     }
 
+    final override val typeParameters: MutableList<FirTypeParameter> = mutableListOf()
+
+    final override lateinit var status: FirDeclarationStatusImpl
+
     override fun <D> transformChildren(transformer: FirTransformer<D>, data: D): FirElement {
         typeParameters.transformInplace(transformer, data)
         status = status.transformSingle(transformer, data)

compiler/fir/tree/src/org/jetbrains/kotlin/fir/declarations/impl/FirMemberFunctionImpl.kt

@@ -20,29 +20,39 @@ import org.jetbrains.kotlin.fir.types.FirType
 import org.jetbrains.kotlin.fir.visitors.FirTransformer
 import org.jetbrains.kotlin.name.Name
 
-class FirMemberFunctionImpl(
-    session: FirSession,
-    psi: PsiElement?,
-    symbol: FirFunctionSymbol,
-    name: Name,
-    visibility: Visibility,
-    modality: Modality?,
-    isExpect: Boolean,
-    isActual: Boolean,
-    isOverride: Boolean,
-    isOperator: Boolean,
-    isInfix: Boolean,
-    isInline: Boolean,
-    isTailRec: Boolean,
-    isExternal: Boolean,
-    isSuspend: Boolean,
-    receiverType: FirType?,
-    returnType: FirType
-) : FirAbstractCallableMember(
-    session, psi, symbol, name, visibility, modality,
-    isExpect, isActual, isOverride, receiverType, returnType
-), FirNamedFunction, FirModifiableFunction {
-    init {
+class FirMemberFunctionImpl : FirAbstractCallableMember, FirNamedFunction, FirModifiableFunction {
+
+    constructor(
+        session: FirSession,
+        psi: PsiElement?,
+        symbol: FirFunctionSymbol,
+        name: Name,
+        receiverType: FirType?,
+        returnType: FirType
+    ) : super(session, psi, symbol, name, receiverType, returnType)
+
+    constructor(
+        session: FirSession,
+        psi: PsiElement?,
+        symbol: FirFunctionSymbol,
+        name: Name,
+        visibility: Visibility,
+        modality: Modality?,
+        isExpect: Boolean,
+        isActual: Boolean,
+        isOverride: Boolean,
+        isOperator: Boolean,
+        isInfix: Boolean,
+        isInline: Boolean,
+        isTailRec: Boolean,
+        isExternal: Boolean,
+        isSuspend: Boolean,
+        receiverType: FirType?,
+        returnType: FirType
+    ) : super(
+        session, psi, symbol, name, visibility, modality,
+        isExpect, isActual, isOverride, receiverType, returnType
+    ) {
         status.isOperator = isOperator
         status.isInfix = isInfix
         status.isInline = isInline

compiler/fir/tree/src/org/jetbrains/kotlin/fir/symbols/impl/FirFunctionSymbol.kt

@@ -11,7 +11,10 @@ import org.jetbrains.kotlin.fir.symbols.CallableId
 import org.jetbrains.kotlin.fir.symbols.ConeFunctionSymbol
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
 
-class FirFunctionSymbol(override val callableId: CallableId) : ConeFunctionSymbol, AbstractFirBasedSymbol<FirCallableMember>() {
+class FirFunctionSymbol(
+    override val callableId: CallableId,
+    val isFakeOverride: Boolean = false
+) : ConeFunctionSymbol, AbstractFirBasedSymbol<FirCallableMember>() {
     override val parameters: List<ConeKotlinType>
         get() = emptyList()
 }