[FIR] Add INVISIBLE_SETTER

analysis/analysis-api-fir/analysis-api-fir-generator/src/org/jetbrains/kotlin/analysis/api/fir/generator/HLDiagnosticConverter.kt

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.analysis.api.types.KtType
 import org.jetbrains.kotlin.lexer.KtKeywordToken
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
 import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.name.CallableId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.KtExpression
@@ -340,6 +341,7 @@ private object FirToKtConversionCreator {
         FirModuleData::class,
         ExpectActualCompatibility.Incompatible::class,
         DeprecationInfo::class,
+        CallableId::class
     )
 
     private val KType.kClass: KClass<*>

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDataClassConverters.kt

@@ -246,6 +246,15 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.INVISIBLE_SETTER) { firDiagnostic ->
+        InvisibleSetterImpl(
+            firSymbolBuilder.variableLikeBuilder.buildVariableSymbol(firDiagnostic.a.fir),
+            firDiagnostic.b,
+            firDiagnostic.c,
+            firDiagnostic as FirPsiDiagnostic,
+            token,
+        )
+    }
     add(FirErrors.INVISIBLE_REFERENCE) { firDiagnostic ->
         InvisibleReferenceImpl(
             firSymbolBuilder.buildSymbol(firDiagnostic.a.fir),

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnostics.kt

@@ -26,6 +26,7 @@ import org.jetbrains.kotlin.fir.FirModuleData
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.lexer.KtKeywordToken
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
+import org.jetbrains.kotlin.name.CallableId
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
@@ -203,6 +204,13 @@ sealed class KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val valOrVar: KtKeywordToken
     }
 
+    abstract class InvisibleSetter : KtFirDiagnostic<PsiElement>() {
+        override val diagnosticClass get() = InvisibleSetter::class
+        abstract val property: KtVariableSymbol
+        abstract val visibility: Visibility
+        abstract val callableId: CallableId
+    }
+
     abstract class InvisibleReference : KtFirDiagnostic<PsiElement>() {
         override val diagnosticClass get() = InvisibleReference::class
         abstract val reference: KtSymbol

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KtFirDiagnosticsImpl.kt

@@ -27,6 +27,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirPsiDiagnostic
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.lexer.KtKeywordToken
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
+import org.jetbrains.kotlin.name.CallableId
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
@@ -231,6 +232,14 @@ internal class ValOrVarOnSecondaryConstructorParameterImpl(
     override val token: ValidityToken,
 ) : KtFirDiagnostic.ValOrVarOnSecondaryConstructorParameter(), KtAbstractFirDiagnostic<KtParameter>
 
+internal class InvisibleSetterImpl(
+    override val property: KtVariableSymbol,
+    override val visibility: Visibility,
+    override val callableId: CallableId,
+    override val firDiagnostic: FirPsiDiagnostic,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.InvisibleSetter(), KtAbstractFirDiagnostic<PsiElement>
+
 internal class InvisibleReferenceImpl(
     override val reference: KtSymbol,
     override val firDiagnostic: FirPsiDiagnostic,

analysis/low-level-api-fir/testdata/lazyResolve/annotationParameters.txt

@@ -1,3 +1,4 @@
+
 RAW_FIR:
 FILE: annotationParameters.kt
     public? final? [RAW_FIR] enum class X : R|kotlin/Enum<X>| {
@@ -19,7 +20,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public? final? [RAW_FIR] class B : R|kotlin/Any| {
@@ -56,7 +57,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public? final? [RAW_FIR] class B : R|kotlin/Any| {
@@ -93,7 +94,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public? final? [RAW_FIR] class B : R|kotlin/Any| {
@@ -130,7 +131,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public? final? [SUPER_TYPES] class B : R|kotlin/Any| {
@@ -167,7 +168,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public final [SUPER_TYPES] class B : R|kotlin/Any| {
@@ -204,7 +205,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public final [SUPER_TYPES] class B : R|kotlin/Any| {
@@ -241,7 +242,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public final [SUPER_TYPES] class B : R|kotlin/Any| {
@@ -278,7 +279,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public final [STATUS] class B : R|kotlin/Any| {
@@ -315,7 +316,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [SUPER_TYPES] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public final [STATUS] class B : R|kotlin/Any| {
@@ -352,7 +353,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public? final? [RAW_FIR] class B : R|kotlin/Any| {
@@ -389,7 +390,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [SUPER_TYPES] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public final [STATUS] class B : R|kotlin/Any| {
@@ -426,7 +427,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [SUPER_TYPES] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public final [STATUS] class B : R|kotlin/Any| {
@@ -463,7 +464,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public? final? [RAW_FIR] class B : R|kotlin/Any| {
@@ -500,7 +501,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public? final? [SUPER_TYPES] class B : R|kotlin/Any| {
@@ -537,7 +538,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public final [SUPER_TYPES] class B : R|kotlin/Any| {
@@ -574,7 +575,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public final [SUPER_TYPES] class B : R|kotlin/Any| {
@@ -611,7 +612,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public final [SUPER_TYPES] class B : R|kotlin/Any| {
@@ -648,7 +649,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public? final? [SUPER_TYPES] class B : R|kotlin/Any| {
@@ -685,7 +686,7 @@ FILE: annotationParameters.kt
         }
 
         public? final? [RAW_FIR] [IsFromPrimaryConstructor=true] val args: A.X = R|<local>/args|
-            [TYPES] public? get(): A.X
+            [TYPES] [ContainingClassKey=Anno] public? get(): A.X
 
     }
     public? final? [SUPER_TYPES] class B : R|kotlin/Any| {
@@ -722,7 +723,7 @@ FILE: annotationParameters.kt
         }
 
         public final [BODY_RESOLVE] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A.X> = R|<local>/args|
-            [BODY_RESOLVE] public get(): <ERROR TYPE REF: Symbol not found for A.X>
+            [BODY_RESOLVE] [ContainingClassKey=Anno] public get(): <ERROR TYPE REF: Symbol not found for A.X>
 
     }
     public final [BODY_RESOLVE] class B : R|kotlin/Any| {

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java

@@ -25481,6 +25481,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                 runTest("compiler/testData/diagnostics/tests/scopes/VisibilityInheritModifier.kt");
             }
 
+            @Test
+            @TestMetadata("visibleSetterFromSyntheticProperty.kt")
+            public void testVisibleSetterFromSyntheticProperty() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/scopes/visibleSetterFromSyntheticProperty.kt");
+            }
+
             @Nested
             @TestMetadata("compiler/testData/diagnostics/tests/scopes/classHeader")
             @TestDataPath("$PROJECT_ROOT")
@@ -25920,6 +25926,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                     runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/protectedCallOnSubClass.kt");
                 }
 
+                @Test
+                @TestMetadata("protectedPropertyInPrimaryConstructor.kt")
+                public void testProtectedPropertyInPrimaryConstructor() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/protectedPropertyInPrimaryConstructor.kt");
+                }
+
                 @Test
                 @TestMetadata("smartcastOnExtensionReceiver.kt")
                 public void testSmartcastOnExtensionReceiver() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java

@@ -25481,6 +25481,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                 runTest("compiler/testData/diagnostics/tests/scopes/VisibilityInheritModifier.kt");
             }
 
+            @Test
+            @TestMetadata("visibleSetterFromSyntheticProperty.kt")
+            public void testVisibleSetterFromSyntheticProperty() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/scopes/visibleSetterFromSyntheticProperty.kt");
+            }
+
             @Nested
             @TestMetadata("compiler/testData/diagnostics/tests/scopes/classHeader")
             @TestDataPath("$PROJECT_ROOT")
@@ -25920,6 +25926,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                     runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/protectedCallOnSubClass.kt");
                 }
 
+                @Test
+                @TestMetadata("protectedPropertyInPrimaryConstructor.kt")
+                public void testProtectedPropertyInPrimaryConstructor() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/protectedPropertyInPrimaryConstructor.kt");
+                }
+
                 @Test
                 @TestMetadata("smartcastOnExtensionReceiver.kt")
                 public void testSmartcastOnExtensionReceiver() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java

@@ -25481,6 +25481,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                 runTest("compiler/testData/diagnostics/tests/scopes/VisibilityInheritModifier.kt");
             }
 
+            @Test
+            @TestMetadata("visibleSetterFromSyntheticProperty.kt")
+            public void testVisibleSetterFromSyntheticProperty() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/scopes/visibleSetterFromSyntheticProperty.kt");
+            }
+
             @Nested
             @TestMetadata("compiler/testData/diagnostics/tests/scopes/classHeader")
             @TestDataPath("$PROJECT_ROOT")
@@ -25920,6 +25926,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                     runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/protectedCallOnSubClass.kt");
                 }
 
+                @Test
+                @TestMetadata("protectedPropertyInPrimaryConstructor.kt")
+                public void testProtectedPropertyInPrimaryConstructor() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/protectedPropertyInPrimaryConstructor.kt");
+                }
+
                 @Test
                 @TestMetadata("smartcastOnExtensionReceiver.kt")
                 public void testSmartcastOnExtensionReceiver() throws Exception {

compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirDiagnosticsList.kt

@@ -24,6 +24,7 @@ import org.jetbrains.kotlin.fir.symbols.impl.*
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.lexer.KtKeywordToken
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
+import org.jetbrains.kotlin.name.CallableId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.*
@@ -88,6 +89,11 @@ object DIAGNOSTICS_LIST : DiagnosticList("FirErrors") {
         val VAL_OR_VAR_ON_SECONDARY_CONSTRUCTOR_PARAMETER by warning<KtParameter>(PositioningStrategy.VAL_OR_VAR_NODE) {
             parameter<KtKeywordToken>("valOrVar")
         }
+        val INVISIBLE_SETTER by error<PsiElement>(PositioningStrategy.ASSIGNMENT_LHS) {
+            parameter<FirPropertySymbol>("property")
+            parameter<Visibility>("visibility")
+            parameter<CallableId>("callableId")
+        }
     }
 
     val UNRESOLVED by object : DiagnosticGroup("Unresolved") {

compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -39,6 +39,7 @@ import org.jetbrains.kotlin.fir.symbols.impl.FirVariableSymbol
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.lexer.KtKeywordToken
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
+import org.jetbrains.kotlin.name.CallableId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.KtAnnotationEntry
@@ -128,6 +129,7 @@ object FirErrors {
     val VAL_OR_VAR_ON_FUN_PARAMETER by warning1<KtParameter, KtKeywordToken>(SourceElementPositioningStrategies.VAL_OR_VAR_NODE)
     val VAL_OR_VAR_ON_CATCH_PARAMETER by warning1<KtParameter, KtKeywordToken>(SourceElementPositioningStrategies.VAL_OR_VAR_NODE)
     val VAL_OR_VAR_ON_SECONDARY_CONSTRUCTOR_PARAMETER by warning1<KtParameter, KtKeywordToken>(SourceElementPositioningStrategies.VAL_OR_VAR_NODE)
+    val INVISIBLE_SETTER by error3<PsiElement, FirPropertySymbol, Visibility, CallableId>(SourceElementPositioningStrategies.ASSIGNMENT_LHS)
 
     // Unresolved
     val INVISIBLE_REFERENCE by error1<PsiElement, FirBasedSymbol<*>>(SourceElementPositioningStrategies.REFERENCE_BY_QUALIFIED)

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/CommonExpressionCheckers.kt

@@ -67,7 +67,7 @@ object CommonExpressionCheckers : ExpressionCheckers() {
 
     override val variableAssignmentCheckers: Set<FirVariableAssignmentChecker>
         get() = setOf(
-            FirValReassignmentChecker,
+            FirReassignmentAndInvisibleSetterChecker,
             FirAssignmentTypeMismatchChecker
         )
 

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirReassignmentAndInvisibleSetterChecker.kt

@@ -0,0 +1,106 @@
+/*
+ * 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.analysis.checkers.expression
+
+import org.jetbrains.kotlin.descriptors.Visibilities
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.checkers.context.findClosest
+import org.jetbrains.kotlin.fir.analysis.checkers.toRegularClassSymbol
+import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
+import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.declarations.FirPropertyAccessor
+import org.jetbrains.kotlin.fir.declarations.utils.visibility
+import org.jetbrains.kotlin.fir.expressions.FirExpressionWithSmartcast
+import org.jetbrains.kotlin.fir.expressions.FirVariableAssignment
+import org.jetbrains.kotlin.fir.expressions.toResolvedCallableSymbol
+import org.jetbrains.kotlin.fir.originalForSubstitutionOverride
+import org.jetbrains.kotlin.fir.references.FirBackingFieldReference
+import org.jetbrains.kotlin.fir.references.FirResolvedNamedReference
+import org.jetbrains.kotlin.fir.resolve.calls.ExpressionReceiverValue
+import org.jetbrains.kotlin.fir.symbols.SymbolInternals
+import org.jetbrains.kotlin.fir.symbols.impl.FirPropertySymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirValueParameterSymbol
+import org.jetbrains.kotlin.fir.visibilityChecker
+
+object FirReassignmentAndInvisibleSetterChecker : FirVariableAssignmentChecker() {
+    override fun check(expression: FirVariableAssignment, context: CheckerContext, reporter: DiagnosticReporter) {
+        checkInvisibleSetter(expression, context, reporter)
+        checkValReassignmentViaBackingField(expression, context, reporter)
+        checkValReassignmentOnValueParameter(expression, context, reporter)
+    }
+
+    private fun checkInvisibleSetter(
+        expression: FirVariableAssignment,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ) {
+        fun shouldInvisibleSetterBeReported(symbol: FirPropertySymbol): Boolean {
+            @OptIn(SymbolInternals::class)
+            val setterFir = symbol.setterSymbol?.fir ?: symbol.originalForSubstitutionOverride?.setterSymbol?.fir
+            if (setterFir != null) {
+                return !context.session.visibilityChecker.isVisible(
+                    setterFir,
+                    context.session,
+                    context.findClosest()!!,
+                    context.containingDeclarations,
+                    ExpressionReceiverValue(expression.dispatchReceiver),
+                )
+            }
+
+            return false
+        }
+
+        val callableSymbol = expression.calleeReference.toResolvedCallableSymbol()
+        if (callableSymbol is FirPropertySymbol && shouldInvisibleSetterBeReported(callableSymbol)) {
+            val explicitReceiver = expression.explicitReceiver
+            // Try to get type from smartcast
+            if (explicitReceiver is FirExpressionWithSmartcast) {
+                val symbol = explicitReceiver.originalType.toRegularClassSymbol(context.session)
+                if (symbol != null) {
+                    for (declarationSymbol in symbol.declarationSymbols) {
+                        if (declarationSymbol is FirPropertySymbol && declarationSymbol.name == callableSymbol.name) {
+                            if (!shouldInvisibleSetterBeReported(declarationSymbol)) {
+                                return
+                            }
+                        }
+                    }
+                }
+            }
+            reporter.reportOn(
+                expression.source,
+                FirErrors.INVISIBLE_SETTER,
+                callableSymbol,
+                callableSymbol.setterSymbol?.visibility ?: Visibilities.Private,
+                callableSymbol.callableId,
+                context
+            )
+        }
+    }
+
+    private fun checkValReassignmentViaBackingField(
+        expression: FirVariableAssignment,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ) {
+        val backingFieldReference = expression.lValue as? FirBackingFieldReference ?: return
+        val propertySymbol = backingFieldReference.resolvedSymbol
+        if (propertySymbol.isVar) return
+        val closestGetter = context.findClosest<FirPropertyAccessor> { it.isGetter }?.symbol ?: return
+        if (propertySymbol.getterSymbol != closestGetter) return
+
+        reporter.reportOn(backingFieldReference.source, FirErrors.VAL_REASSIGNMENT_VIA_BACKING_FIELD, propertySymbol, context)
+    }
+
+    private fun checkValReassignmentOnValueParameter(
+        expression: FirVariableAssignment,
+        context: CheckerContext,
+        reporter: DiagnosticReporter
+    ) {
+        val valueParameter = (expression.lValue as? FirResolvedNamedReference)?.resolvedSymbol as? FirValueParameterSymbol ?: return
+        reporter.reportOn(expression.lValue.source, FirErrors.VAL_REASSIGNMENT, valueParameter, context)
+    }
+}

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/expression/FirValReassignmentChecker.kt

@@ -1,49 +0,0 @@
-/*
- * 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.analysis.checkers.expression
-
-import org.jetbrains.kotlin.config.LanguageFeature
-import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
-import org.jetbrains.kotlin.fir.analysis.checkers.context.findClosest
-import org.jetbrains.kotlin.fir.analysis.diagnostics.DiagnosticReporter
-import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
-import org.jetbrains.kotlin.fir.analysis.diagnostics.reportOn
-import org.jetbrains.kotlin.fir.declarations.FirPropertyAccessor
-import org.jetbrains.kotlin.fir.expressions.FirVariableAssignment
-import org.jetbrains.kotlin.fir.languageVersionSettings
-import org.jetbrains.kotlin.fir.references.FirBackingFieldReference
-import org.jetbrains.kotlin.fir.references.FirResolvedNamedReference
-import org.jetbrains.kotlin.fir.symbols.impl.FirValueParameterSymbol
-
-object FirValReassignmentChecker : FirVariableAssignmentChecker() {
-    override fun check(expression: FirVariableAssignment, context: CheckerContext, reporter: DiagnosticReporter) {
-        checkValReassignmentViaBackingField(expression, context, reporter)
-        checkValReassignmentOnValueParameter(expression, context, reporter)
-    }
-
-    private fun checkValReassignmentViaBackingField(
-        expression: FirVariableAssignment,
-        context: CheckerContext,
-        reporter: DiagnosticReporter
-    ) {
-        val backingFieldReference = expression.lValue as? FirBackingFieldReference ?: return
-        val propertySymbol = backingFieldReference.resolvedSymbol
-        if (propertySymbol.isVar) return
-        val closestGetter = context.findClosest<FirPropertyAccessor> { it.isGetter }?.symbol ?: return
-        if (propertySymbol.getterSymbol != closestGetter) return
-
-        reporter.reportOn(backingFieldReference.source, FirErrors.VAL_REASSIGNMENT_VIA_BACKING_FIELD, propertySymbol, context)
-    }
-
-    private fun checkValReassignmentOnValueParameter(
-        expression: FirVariableAssignment,
-        context: CheckerContext,
-        reporter: DiagnosticReporter
-    ) {
-        val valueParameter = (expression.lValue as? FirResolvedNamedReference)?.resolvedSymbol as? FirValueParameterSymbol ?: return
-        reporter.reportOn(expression.lValue.source, FirErrors.VAL_REASSIGNMENT, valueParameter, context)
-    }
-}

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.FIR
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.FQ_NAMES_IN_TYPES
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.FUNCTION_PARAMETERS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.MODULE_DATA
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.NAME_OF_CONTAINING_DECLARATION_OR_FILE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.NOT_RENDERED
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.NULLABLE_STRING
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.RENDER_CLASS_OR_OBJECT
@@ -247,6 +248,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INVALID_DEFAULT_F
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INVALID_IF_AS_EXPRESSION
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INVALID_TYPE_OF_ANNOTATION_MEMBER
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INVISIBLE_REFERENCE
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INVISIBLE_SETTER
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.IS_ENUM_ENTRY
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.ITERATOR_AMBIGUITY
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.KCLASS_WITH_NULLABLE_TYPE_PARAMETER_IN_SIGNATURE
@@ -554,6 +556,7 @@ class FirDefaultErrorMessages {
 
             // Unresolved
             map.put(INVISIBLE_REFERENCE, "Symbol {0} is invisible", SYMBOL)
+            map.put(INVISIBLE_SETTER, "Cannot access ''{0}'': it is {1} in {2}", VARIABLE_NAME, VISIBILITY, NAME_OF_CONTAINING_DECLARATION_OR_FILE)
             map.put(UNRESOLVED_REFERENCE, "Unresolved reference: {0}", NULLABLE_STRING)
             map.put(UNRESOLVED_LABEL, "Unresolved label")
             map.put(DESERIALIZATION_ERROR, "Deserialization error")

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDiagnosticRenderers.kt

@@ -14,16 +14,14 @@ import org.jetbrains.kotlin.diagnostics.rendering.Renderer
 import org.jetbrains.kotlin.fir.FirElement
 import org.jetbrains.kotlin.fir.FirModuleData
 import org.jetbrains.kotlin.fir.FirRenderer
-import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.utils.*
 import org.jetbrains.kotlin.fir.render
-import org.jetbrains.kotlin.fir.resolve.dfa.cfg.isLocalClassOrAnonymousObject
-import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.firUnsafe
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.SymbolInternals
 import org.jetbrains.kotlin.fir.symbols.impl.*
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.fir.types.render
+import org.jetbrains.kotlin.name.CallableId
 
 object FirDiagnosticRenderers {
     val NULLABLE_STRING = Renderer<String?> { it ?: "null" }
@@ -139,6 +137,15 @@ object FirDiagnosticRenderers {
         "Module ${it.name}"
     }
 
+    val NAME_OF_CONTAINING_DECLARATION_OR_FILE = Renderer { symbol: CallableId ->
+        val classId = symbol.classId
+        if (classId == null) {
+            "file"
+        } else {
+            "'${classId}'"
+        }
+    }
+
     @Suppress("FunctionName")
     fun <T> COLLECTION(renderer: ContextIndependentParameterRenderer<T>): ContextIndependentParameterRenderer<Collection<T>> {
         return Renderer { list ->

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

@@ -11,11 +11,13 @@ import org.jetbrains.kotlin.descriptors.java.JavaVisibilities
 import org.jetbrains.kotlin.fir.*
 import org.jetbrains.kotlin.fir.declarations.FirDeclaration
 import org.jetbrains.kotlin.fir.declarations.FirFile
+import org.jetbrains.kotlin.fir.declarations.synthetic.FirSyntheticPropertyAccessor
 import org.jetbrains.kotlin.fir.declarations.utils.visibility
 import org.jetbrains.kotlin.fir.resolve.calls.FirSyntheticPropertySymbol
 import org.jetbrains.kotlin.fir.resolve.calls.ReceiverValue
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirNamedFunctionSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirPropertyAccessorSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirVariableSymbol
 
 @NoMutableState
@@ -37,19 +39,25 @@ object FirJavaVisibilityChecker : FirVisibilityChecker() {
                     val ownerLookupTag = symbol.getOwnerLookupTag() ?: return false
                     if (canSeeProtectedMemberOf(
                             containingDeclarations, dispatchReceiver, ownerLookupTag, session,
-                            isVariableOrNamedFunction = symbol is FirVariableSymbol || symbol is FirNamedFunctionSymbol
+                            isVariableOrNamedFunction = symbol is FirVariableSymbol || symbol is FirNamedFunctionSymbol || symbol is FirPropertyAccessorSymbol,
+                            isSyntheticProperty = symbol.fir is FirSyntheticPropertyAccessor
                         )
                     ) return true
 
                     // FE1.0 allows calling public setters with property assignment syntax if the getter is protected.
                     if (!isCallToPropertySetter || symbol !is FirSyntheticPropertySymbol) return false
-                    val setterVisibility = symbol.setterSymbol?.visibility
+                    symbol.setterSymbol?.visibility == Visibilities.Public
-                    setterVisibility != null && setterVisibility == Visibilities.Public
                 }
             }
 
             JavaVisibilities.PackageVisibility -> {
-                symbol.packageFqName() == useSiteFile.packageFqName
+                if (symbol.packageFqName() == useSiteFile.packageFqName) {
+                    true
+                } else if (symbol.fir is FirSyntheticPropertyAccessor) {
+                    symbol.getOwnerLookupTag()?.classId?.packageFqName == useSiteFile.packageFqName
+                } else {
+                    false
+                }
             }
 
             else -> true

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/declarations/annotation.txt

@@ -17,7 +17,7 @@ FILE: annotation.kt
         }
 
         @base() public? final? [IsFromPrimaryConstructor=true] val x: Int = R|<local>/x|
-            public? get(): Int
+            [ContainingClassKey=correct] public? get(): Int
 
         @base() public? [ContainingClassKey=correct] constructor(): R|correct| {
             this<R|correct|>(IntegerLiteral(0))

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/declarations/derivedClass.txt

@@ -5,7 +5,7 @@ FILE: derivedClass.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val x: T = R|<local>/x|
-            public? get(): T
+            [ContainingClassKey=Base] public? get(): T
 
     }
     public? final? class Derived<T : Any> : Base<T> {

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/declarations/enums.txt

@@ -20,10 +20,10 @@ FILE: enums.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val m: Double = R|<local>/m|
-            public? get(): Double
+            [ContainingClassKey=Planet] public? get(): Double
 
         internal final? [IsFromPrimaryConstructor=true] val r: Double = R|<local>/r|
-            internal get(): Double
+            [ContainingClassKey=Planet] internal get(): Double
 
         public final static [ContainingClassKey=Planet] enum entry MERCURY: R|Planet| = object : R|Planet| {
             private [ContainingClassKey=<anonymous>] constructor(): R|<anonymous>| {
@@ -86,7 +86,7 @@ FILE: enums.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val signature: String = R|<local>/signature|
-            public? get(): String
+            [ContainingClassKey=PseudoInsn] public? get(): String
 
         public final static [ContainingClassKey=PseudoInsn] enum entry FIX_STACK_BEFORE_JUMP: R|PseudoInsn| = object : R|PseudoInsn| {
             private [ContainingClassKey=<anonymous>] constructor(): R|<anonymous>| {

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/declarations/enums2.txt

@@ -19,7 +19,7 @@ FILE: enums2.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val x: Some = R|<local>/x|
-            public? get(): Some
+            [ContainingClassKey=SomeEnum] public? get(): Some
 
         public final static [ContainingClassKey=SomeEnum] enum entry FIRST: R|SomeEnum| = object : R|SomeEnum| {
             private [ContainingClassKey=<anonymous>] constructor(): R|<anonymous>| {

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/declarations/nestedClass.txt

@@ -5,7 +5,7 @@ FILE: nestedClass.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val s: String = R|<local>/s|
-            public? get(): String
+            [ContainingClassKey=Base] public? get(): String
 
     }
     public? final? class Outer : R|kotlin/Any| {

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/annotated.txt

@@ -26,10 +26,10 @@ FILE: annotated.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val x: Int = R|<local>/x|
-            public? get(): Int
+            [ContainingClassKey=Two] public? get(): Int
 
         public? final? [IsFromPrimaryConstructor=true] val y: Int = R|<local>/y|
-            public? get(): Int
+            [ContainingClassKey=Two] public? get(): Int
 
         public final operator fun component1(): Int
 

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/arrayAccess.txt

@@ -10,7 +10,7 @@ FILE: arrayAccess.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val v: IntArray = R|<local>/v|
-            public? get(): IntArray
+            [ContainingClassKey=Wrapper] public? get(): IntArray
 
     }
     public? final? fun test(a: IntArray, w: Wrapper): <implicit> {

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/calls.txt

@@ -14,8 +14,8 @@ FILE: calls.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] var x: Int = R|<local>/x|
-            public? get(): Int
+            [ContainingClassKey=My] public? get(): Int
-            public? set(value: Int): R|kotlin/Unit|
+            [ContainingClassKey=My] public? set(value: Int): R|kotlin/Unit|
 
         public? final? operator fun invoke(): <implicit> {
             ^invoke x#

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/collectionLiterals.txt

@@ -5,7 +5,7 @@ FILE: collectionLiterals.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val arr: IntArray = R|<local>/arr|
-            public? get(): IntArray
+            [ContainingClassKey=Ann1] public? get(): IntArray
 
     }
     public? final? annotation class Ann2 : R|kotlin/Annotation| {
@@ -14,7 +14,7 @@ FILE: collectionLiterals.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val arr: DoubleArray = R|<local>/arr|
-            public? get(): DoubleArray
+            [ContainingClassKey=Ann2] public? get(): DoubleArray
 
     }
     public? final? annotation class Ann3 : R|kotlin/Annotation| {
@@ -23,7 +23,7 @@ FILE: collectionLiterals.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val arr: Array<String> = R|<local>/arr|
-            public? get(): Array<String>
+            [ContainingClassKey=Ann3] public? get(): Array<String>
 
     }
     @Ann1(<implicitArrayOf>()) @Ann2(<implicitArrayOf>()) @Ann3(<implicitArrayOf>()) public? final? class Zero : R|kotlin/Any| {

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/destructuring.txt

@@ -5,13 +5,13 @@ FILE: destructuring.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val first: Int = R|<local>/first|
-            public? get(): Int
+            [ContainingClassKey=Some] public? get(): Int
 
         public? final? [IsFromPrimaryConstructor=true] val second: Double = R|<local>/second|
-            public? get(): Double
+            [ContainingClassKey=Some] public? get(): Double
 
         public? final? [IsFromPrimaryConstructor=true] val third: String = R|<local>/third|
-            public? get(): String
+            [ContainingClassKey=Some] public? get(): String
 
         public final operator fun component1(): Int
 

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/for.txt

@@ -55,10 +55,10 @@ FILE: for.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val x: Int = R|<local>/x|
-            public? get(): Int
+            [ContainingClassKey=Some] public? get(): Int
 
         public? final? [IsFromPrimaryConstructor=true] val y: Int = R|<local>/y|
-            public? get(): Int
+            [ContainingClassKey=Some] public? get(): Int
 
         public final operator fun component1(): Int
 

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/lambda.txt

@@ -5,10 +5,10 @@ FILE: lambda.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val x: Int = R|<local>/x|
-            public? get(): Int
+            [ContainingClassKey=Tuple] public? get(): Int
 
         public? final? [IsFromPrimaryConstructor=true] val y: Int = R|<local>/y|
-            public? get(): Int
+            [ContainingClassKey=Tuple] public? get(): Int
 
         public final operator fun component1(): Int
 

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/locals.txt

@@ -6,7 +6,7 @@ FILE: locals.kt
             }
 
             public? final? [IsFromPrimaryConstructor=true] val pp: Int = R|<local>/pp|
-                public? get(): Int
+                [ContainingClassKey=Local] public? get(): Int
 
             public? final? fun diff(): <implicit> {
                 ^diff pp#.minus#(p#)

compiler/fir/raw-fir/psi2fir/testData/rawBuilder/expressions/unary.txt

@@ -36,7 +36,7 @@ FILE: unary.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val i: Int = R|<local>/i|
-            public? get(): Int
+            [ContainingClassKey=X] public? get(): Int
 
     }
     public? final? fun test2(x: X): R|kotlin/Unit| {
@@ -79,7 +79,7 @@ FILE: unary.kt
         }
 
         public? final? [IsFromPrimaryConstructor=true] val arr: Array<Int> = R|<local>/arr|
-            public? get(): Array<Int>
+            [ContainingClassKey=Y] public? get(): Array<Int>
 
     }
     public? final? fun test4(y: Y): R|kotlin/Unit| {

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

@@ -5,18 +5,17 @@
 
 package org.jetbrains.kotlin.fir
 
+import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.descriptors.Visibility
 import org.jetbrains.kotlin.fir.declarations.*
+import org.jetbrains.kotlin.fir.declarations.synthetic.FirSyntheticPropertyAccessor
 import org.jetbrains.kotlin.fir.declarations.utils.*
 import org.jetbrains.kotlin.fir.expressions.FirPropertyAccessExpression
 import org.jetbrains.kotlin.fir.expressions.FirVariableAssignment
 import org.jetbrains.kotlin.fir.references.FirSuperReference
 import org.jetbrains.kotlin.fir.resolve.*
-import org.jetbrains.kotlin.fir.resolve.calls.Candidate
+import org.jetbrains.kotlin.fir.resolve.calls.*
-import org.jetbrains.kotlin.fir.resolve.calls.ExpressionReceiverValue
-import org.jetbrains.kotlin.fir.resolve.calls.FirSyntheticFunctionSymbol
-import org.jetbrains.kotlin.fir.resolve.calls.ReceiverValue
 import org.jetbrains.kotlin.fir.symbols.ConeClassLikeLookupTag
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.*
@@ -167,7 +166,8 @@ abstract class FirVisibilityChecker : FirSessionComponent {
                 val ownerId = symbol.getOwnerLookupTag()
                 ownerId != null && canSeeProtectedMemberOf(
                     containingDeclarations, dispatchReceiver, ownerId, session,
-                    isVariableOrNamedFunction = symbol is FirVariableSymbol || symbol is FirNamedFunctionSymbol
+                    isVariableOrNamedFunction = symbol is FirVariableSymbol || symbol is FirNamedFunctionSymbol || symbol is FirPropertyAccessorSymbol,
+                    symbol.fir is FirSyntheticPropertyAccessor
                 )
             }
 
@@ -233,7 +233,8 @@ abstract class FirVisibilityChecker : FirSessionComponent {
         dispatchReceiver: ReceiverValue?,
         ownerLookupTag: ConeClassLikeLookupTag,
         session: FirSession,
-        isVariableOrNamedFunction: Boolean
+        isVariableOrNamedFunction: Boolean,
+        isSyntheticProperty: Boolean
     ): Boolean {
         dispatchReceiver?.ownerIfCompanion(session)?.let { companionOwnerLookupTag ->
             if (containingUseSiteClass.isSubClass(companionOwnerLookupTag, session)) return true
@@ -241,7 +242,13 @@ abstract class FirVisibilityChecker : FirSessionComponent {
 
         return when {
             !containingUseSiteClass.isSubClass(ownerLookupTag, session) -> false
-            isVariableOrNamedFunction -> doesReceiverFitForProtectedVisibility(dispatchReceiver, containingUseSiteClass, session)
+            isVariableOrNamedFunction -> doesReceiverFitForProtectedVisibility(
+                dispatchReceiver,
+                containingUseSiteClass,
+                ownerLookupTag,
+                isSyntheticProperty,
+                session
+            )
             else -> true
         }
     }
@@ -249,6 +256,8 @@ abstract class FirVisibilityChecker : FirSessionComponent {
     private fun doesReceiverFitForProtectedVisibility(
         dispatchReceiver: ReceiverValue?,
         containingUseSiteClass: FirClass,
+        ownerLookupTag: ConeClassLikeLookupTag,
+        isSyntheticProperty: Boolean,
         session: FirSession
     ): Boolean {
         if (dispatchReceiver == null) return true
@@ -264,9 +273,21 @@ abstract class FirVisibilityChecker : FirSessionComponent {
             errorTypesEqualToAnything = false,
             stubTypesEqualToAnything = false
         )
-        return AbstractTypeChecker.isSubtypeOf(
+        if (AbstractTypeChecker.isSubtypeOf(
-            typeCheckerState, dispatchReceiverType.fullyExpandedType(session), containingUseSiteClass.typeWithStarProjections()
+                typeCheckerState, dispatchReceiverType.fullyExpandedType(session), containingUseSiteClass.typeWithStarProjections()
-        )
+            )
+        ) {
+            return true
+        }
+
+        if (isSyntheticProperty) {
+            return if (session.languageVersionSettings.supportsFeature(LanguageFeature.ImproveReportingDiagnosticsOnProtectedMembersOfBaseClass))
+                containingUseSiteClass.classId.packageFqName == ownerLookupTag.classId.packageFqName
+            else
+                true
+        }
+
+        return false
     }
 
     private fun FirClass.isSubClass(ownerLookupTag: ConeClassLikeLookupTag, session: FirSession): Boolean {
@@ -295,14 +316,31 @@ abstract class FirVisibilityChecker : FirSessionComponent {
         dispatchReceiver: ReceiverValue?,
         ownerLookupTag: ConeClassLikeLookupTag,
         session: FirSession,
-        isVariableOrNamedFunction: Boolean
+        isVariableOrNamedFunction: Boolean,
+        isSyntheticProperty: Boolean
     ): Boolean {
         if (canSeePrivateMemberOf(containingDeclarationOfUseSite, ownerLookupTag, session)) return true
 
         for (containingDeclaration in containingDeclarationOfUseSite) {
-            if (containingDeclaration !is FirClass) continue
+            if (containingDeclaration is FirClass) {
-            val boundSymbol = containingDeclaration.symbol
+                val boundSymbol = containingDeclaration.symbol
-            if (canSeeProtectedMemberOf(boundSymbol.fir, dispatchReceiver, ownerLookupTag, session, isVariableOrNamedFunction)) return true
+                if (canSeeProtectedMemberOf(
+                        boundSymbol.fir,
+                        dispatchReceiver,
+                        ownerLookupTag,
+                        session,
+                        isVariableOrNamedFunction,
+                        isSyntheticProperty
+                    )
+                ) return true
+            } else if (containingDeclaration is FirFile) {
+                if (isSyntheticProperty &&
+                    session.languageVersionSettings.supportsFeature(LanguageFeature.ImproveReportingDiagnosticsOnProtectedMembersOfBaseClass) &&
+                    containingDeclaration.packageFqName == ownerLookupTag.classId.packageFqName
+                ) {
+                    return true
+                }
+            }
         }
 
         return false

compiler/testData/diagnostics/tests/OverridenSetterVisibility.fir.kt

@@ -1,29 +0,0 @@
-public interface ITest {
-    public var prop : Int
-        get() = 12
-        set(value) {}
-}
-
-abstract class ATest {
-    protected open var prop2 : Int
-        get() = 13
-        set(value) {}
-}
-
-class Test: ATest(), ITest {
-    override var prop : Int
-        get() = 12
-        <!CANNOT_WEAKEN_ACCESS_PRIVILEGE!>private<!> set(value) {}
-
-    override var prop2 : Int
-        get() = 14
-        <!CANNOT_CHANGE_ACCESS_PRIVILEGE, SETTER_VISIBILITY_INCONSISTENT_WITH_PROPERTY_VISIBILITY!>internal<!> set(value) {}
-}
-
-fun main() {
-    val test = Test()
-    test.prop = 12
-
-    val itest: ITest = test
-    itest.prop = 12 // No error here
-}

compiler/testData/diagnostics/tests/OverridenSetterVisibility.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 public interface ITest {
     public var prop : Int
         get() = 12

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt2330.fir.kt

@@ -23,23 +23,23 @@ class P {
 
 fun foo() {
     val p = P()
-    p.x = 34 //should be an error here
+    <!INVISIBLE_SETTER!>p.x<!> = 34 //should be an error here
     p.y = 23
 
     fun inner() {
-        p.x = 44
+        <!INVISIBLE_SETTER!>p.x<!> = 44
     }
 }
 
 class R {
     val p = P();
     init {
-        p.x = 42
+        <!INVISIBLE_SETTER!>p.x<!> = 42
     }
 
     val testInGetterInOtherClass : Int
         get() {
-            p.x = 33
+            <!INVISIBLE_SETTER!>p.x<!> = 33
             return 3
         }
 }
@@ -50,4 +50,4 @@ fun test() {
             <!UNRESOLVED_REFERENCE!>p<!>.x = 43
         }
     }
-}
+}

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt2960.fir.kt

@@ -1,36 +0,0 @@
-//KT-2960 Perform control flow checks for package property initializers
-
-package b
-
-class P {
-    var x : Int = 0
-        private set
-}
-
-val p = P()
-var f = { -> p.x = 32 }
-
-val o = object {
-    fun run() {
-        p.x = 4
-
-        val z : Int
-        doSmth(<!UNINITIALIZED_VARIABLE!>z<!>)
-    }
-}
-
-val g = { ->
-    val x: Int
-    doSmth(<!UNINITIALIZED_VARIABLE!>x<!>)
-}
-
-class A {
-    val a : Int = 1
-      get() {
-          val x : Int
-          doSmth(<!UNINITIALIZED_VARIABLE!>x<!>)
-          return field
-      }
-}
-
-fun doSmth(i: Int) = i

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt2960.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 //KT-2960 Perform control flow checks for package property initializers
 
 package b

compiler/testData/diagnostics/tests/controlFlowAnalysis/privateSetter.fir.kt

@@ -1,17 +0,0 @@
-open class X(s : String) {
-    public var n: String = s
-        private set
-
-}
-
-class Z : X("subclass") {
-    fun print(): String {
-        n = n
-        return n;
-    }
-}
-
-
-fun box() : String {
-    return Z().print() //error
-}

compiler/testData/diagnostics/tests/controlFlowAnalysis/privateSetter.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 open class X(s : String) {
     public var n: String = s
         private set

compiler/testData/diagnostics/tests/privateInFile/visibility.fir.kt

@@ -40,7 +40,7 @@ fun test() {
     val po = <!INVISIBLE_REFERENCE!>PO<!>
 
     val v = xx
-    xx = 40
+    <!INVISIBLE_SETTER("xx; private; file")!>xx<!> = 40
 }
 
 class B : <!EXPOSED_SUPER_CLASS, INVISIBLE_REFERENCE!>A<!>() {}

compiler/testData/diagnostics/tests/protectedWithGenericsInDifferentPackage.fir.kt

@@ -28,14 +28,14 @@ fun test(s: bar.Sub<String>) {
     s.<!INVISIBLE_REFERENCE!>name<!>
     s.<!INVISIBLE_REFERENCE!>name<!> = ""
     s.name2
-    s.name2 = ""
+    <!INVISIBLE_SETTER!>s.name2<!> = ""
     s.<!INVISIBLE_REFERENCE!>doSomething<!>()
     s.doSomething2()
     val s2: Super<String> = s
     s2.<!INVISIBLE_REFERENCE!>name<!>
     s2.<!INVISIBLE_REFERENCE!>name<!> = ""
     s2.name2
-    s2.name2 = ""
+    <!INVISIBLE_SETTER!>s2.name2<!> = ""
     s2.<!INVISIBLE_REFERENCE!>doSomething<!>()
     s2.doSomething2()
 }

compiler/testData/diagnostics/tests/scopes/invisibleSetter.fir.kt

@@ -1,9 +0,0 @@
-class A<T> {
-    public var x: Int = 0
-        private set
-}
-
-fun main() {
-    val a = A<Any>()
-    a.x = 1
-}

compiler/testData/diagnostics/tests/scopes/invisibleSetter.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 class A<T> {
     public var x: Int = 0
         private set

compiler/testData/diagnostics/tests/scopes/protectedVisibility/protectedPropertyInPrimaryConstructor.kt

@@ -0,0 +1,9 @@
+// FIR_IDENTICAL
+class Test(protected var prop1: Int = 1) {
+    protected var prop2: Int = 2
+
+    private fun test() {
+        prop1 = 3
+        prop2 = 4
+    }
+}

compiler/testData/diagnostics/tests/scopes/protectedVisibility/protectedPropertyInPrimaryConstructor.txt

@@ -0,0 +1,11 @@
+package
+
+public final class Test {
+    public constructor Test(/*0*/ prop1: kotlin.Int = ...)
+    protected final var prop1: kotlin.Int
+    protected final var prop2: kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    private final fun test(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/scopes/protectedVisibility/syntheticPropertyExtensions.fir.kt

@@ -22,8 +22,7 @@ class B : A() {
         b.bar = b.bar + ""
 
         a.<!INVISIBLE_REFERENCE!>foo<!>
-        // TODO: should be INVISIBLE_SETTER
+        <!INVISIBLE_SETTER!>a.bar<!> = a.bar + ""
-        a.bar = a.bar + ""
 
         if (a is B) {
             a.foo
@@ -33,13 +32,12 @@ class B : A() {
         if (d.x is B) {
             d.x.abc // Ok
             d.x.<!INVISIBLE_REFERENCE!>foo<!>
-            // TODO: should be INVISIBLE_SETTER
+            <!INVISIBLE_SETTER!>d.x.bar<!> = d.x.bar + ""
-            d.x.bar = d.x.bar + ""
         }
     }
 }
 
 fun baz(a: A) {
     a.<!INVISIBLE_REFERENCE!>foo<!>
-    a.bar = a.bar + ""
+    <!INVISIBLE_SETTER!>a.bar<!> = a.bar + ""
 }

compiler/testData/diagnostics/tests/scopes/protectedVisibility/syntheticPropertyExtensions.kt

@@ -22,7 +22,6 @@ class B : A() {
         b.bar = b.bar + ""
 
         a.<!INVISIBLE_MEMBER!>foo<!>
-        // TODO: should be INVISIBLE_SETTER
         a.<!INVISIBLE_SETTER!>bar<!> = a.bar + ""
 
         if (a is B) {
@@ -33,7 +32,6 @@ class B : A() {
         if (d.x is B) {
             d.x.abc // Ok
             d.x.<!INVISIBLE_MEMBER!>foo<!>
-            // TODO: should be INVISIBLE_SETTER
             d.x.<!INVISIBLE_SETTER!>bar<!> = d.x.bar + ""
         }
     }

compiler/testData/diagnostics/tests/scopes/protectedVisibility/withSmartcast.fir.kt

@@ -15,7 +15,7 @@ class Derived : Base() {
         x.<!INVISIBLE_REFERENCE!>bar<!>()
 
         x.<!INVISIBLE_REFERENCE!>x<!> = x.<!INVISIBLE_REFERENCE!>x<!> + 1
-        x.y = x.y + 1
+        <!INVISIBLE_SETTER!>x.y<!> = x.y + 1
 
         if (x is Derived) {
             x.foo()

compiler/testData/diagnostics/tests/scopes/visibleSetterFromSyntheticProperty.kt

@@ -0,0 +1,21 @@
+// FIR_IDENTICAL
+
+// FILE: Java.java
+
+public abstract class Java {
+    private String _name = null;
+
+    void setName(String name) {
+        this._name = name;
+    }
+
+    public String getName() {
+        return _name;
+    }
+}
+
+// FILE: main.kt
+
+fun Java.test(name: String) {
+    this.name = name
+}

compiler/testData/diagnostics/tests/scopes/visibleSetterFromSyntheticProperty.txt

@@ -0,0 +1,13 @@
+package
+
+public fun Java.test(/*0*/ name: kotlin.String): kotlin.Unit
+
+public abstract class Java {
+    public constructor Java()
+    private final var _name: kotlin.String!
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open fun getName(): kotlin.String!
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public/*package*/ open fun setName(/*0*/ name: kotlin.String!): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/syntheticExtensions/javaProperties/OnlyPublic.fir.kt

@@ -8,7 +8,7 @@ fun foo(javaClass: JavaClass) {
     javaClass.<!INVISIBLE_REFERENCE!>somethingProtected<!>
     javaClass.<!INVISIBLE_REFERENCE!>somethingPrivate<!>
     javaClass.<!INVISIBLE_REFERENCE!>somethingPackage<!>
-    javaClass.somethingPublic = 1
+    <!INVISIBLE_SETTER!>javaClass.somethingPublic<!> = 1
 }
 
 // FILE: JavaClass.java

compiler/testData/diagnostics/tests/visibility/invisibleSetterOfJavaClass.fir.kt

@@ -18,12 +18,12 @@ class Data(var x: Foo)
 
 class B : Foo() {
     fun baz(a: Foo, t: Foo, d: Data) {
-        a.bar = t.bar
+        <!INVISIBLE_SETTER!>a.bar<!> = t.bar
-        a.foo = t.foo
+        <!INVISIBLE_SETTER!>a.foo<!> = t.foo
 
         if (d.x is B) {
-            d.x.bar = d.x.bar + ""
+            <!INVISIBLE_SETTER!>d.x.bar<!> = d.x.bar + ""
-            d.x.foo = d.x.foo + ""
+            <!INVISIBLE_SETTER!>d.x.foo<!> = d.x.foo + ""
         }
     }
 }

compiler/testData/diagnostics/tests/visibility/invisibleSetterOfJavaClassWithDisabledFeature.fir.kt

@@ -19,11 +19,11 @@ class Data(var x: Foo)
 class B : Foo() {
     fun baz(a: Foo, t: Foo, d: Data) {
         a.bar = t.bar
-        a.foo = t.foo
+        <!INVISIBLE_SETTER!>a.foo<!> = t.foo
 
         if (d.x is B) {
             d.x.bar = d.x.bar + ""
-            d.x.foo = d.x.foo + ""
+            <!INVISIBLE_SETTER!>d.x.foo<!> = d.x.foo + ""
         }
     }
 }

compiler/testData/diagnostics/tests/visibility/lackOfInvisibleSetterOfJavaClassInSamePackage.fir.kt

@@ -13,11 +13,11 @@ class Data(var x: Foo)
 class B : Foo() {
     fun baz(a: Foo, t: Foo, d: Data) {
         a.bar = t.bar
-        a.foo = t.foo
+        <!INVISIBLE_SETTER!>a.foo<!> = t.foo
 
         if (d.x is B) {
             d.x.bar = d.x.bar + ""
-            d.x.foo = d.x.foo + ""
+            <!INVISIBLE_SETTER!>d.x.foo<!> = d.x.foo + ""
         }
     }
 }

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java

@@ -25493,6 +25493,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/scopes/VisibilityInheritModifier.kt");
             }
 
+            @Test
+            @TestMetadata("visibleSetterFromSyntheticProperty.kt")
+            public void testVisibleSetterFromSyntheticProperty() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/scopes/visibleSetterFromSyntheticProperty.kt");
+            }
+
             @Nested
             @TestMetadata("compiler/testData/diagnostics/tests/scopes/classHeader")
             @TestDataPath("$PROJECT_ROOT")
@@ -25932,6 +25938,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                     runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/protectedCallOnSubClass.kt");
                 }
 
+                @Test
+                @TestMetadata("protectedPropertyInPrimaryConstructor.kt")
+                public void testProtectedPropertyInPrimaryConstructor() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/scopes/protectedVisibility/protectedPropertyInPrimaryConstructor.kt");
+                }
+
                 @Test
                 @TestMetadata("smartcastOnExtensionReceiver.kt")
                 public void testSmartcastOnExtensionReceiver() throws Exception {