FIR: introduce INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER

compiler/fir/analysis-tests/testData/resolve/diagnostics/incompatibleModifiers.kt

@@ -22,7 +22,7 @@ abstract class K {
     <!INCOMPATIBLE_MODIFIERS!>private<!> <!INCOMPATIBLE_MODIFIERS!>abstract<!> val i2: Int
 }
 
-private open class L : K()
+private open <!INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER!>class L<!> : K()
 private abstract class M : K()
 
 class X {

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

@@ -299,6 +299,14 @@ object DIAGNOSTICS_LIST : DiagnosticList() {
             parameter<FirClass<*>>("classOrObject")
             parameter<FirCallableDeclaration<*>>("missingDeclaration")
         }
+        val INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER by error<FirSourceElement, KtClassOrObject>(PositioningStrategy.DECLARATION_NAME) {
+            parameter<FirClass<*>>("classOrObject")
+            parameter<FirCallableDeclaration<*>>("invisibleDeclaration")
+        }
+        val INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER_WARNING by warning<FirSourceElement, KtClassOrObject>(PositioningStrategy.DECLARATION_NAME) {
+            parameter<FirClass<*>>("classOrObject")
+            parameter<FirCallableDeclaration<*>>("invisibleDeclaration")
+        }
         val MANY_IMPL_MEMBER_NOT_IMPLEMENTED by error<FirSourceElement, KtClassOrObject>(PositioningStrategy.DECLARATION_NAME) {
             parameter<FirClass<*>>("classOrObject")
             parameter<FirCallableDeclaration<*>>("missingDeclaration")

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

@@ -210,6 +210,8 @@ object FirErrors {
     val OVERRIDING_FINAL_MEMBER by error2<FirSourceElement, KtNamedDeclaration, FirCallableDeclaration<*>, Name>(SourceElementPositioningStrategies.OVERRIDE_MODIFIER)
     val ABSTRACT_MEMBER_NOT_IMPLEMENTED by error2<FirSourceElement, KtClassOrObject, FirClass<*>, FirCallableDeclaration<*>>(SourceElementPositioningStrategies.DECLARATION_NAME)
     val ABSTRACT_CLASS_MEMBER_NOT_IMPLEMENTED by error2<FirSourceElement, KtClassOrObject, FirClass<*>, FirCallableDeclaration<*>>(SourceElementPositioningStrategies.DECLARATION_NAME)
+    val INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER by error2<FirSourceElement, KtClassOrObject, FirClass<*>, FirCallableDeclaration<*>>(SourceElementPositioningStrategies.DECLARATION_NAME)
+    val INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER_WARNING by warning2<FirSourceElement, KtClassOrObject, FirClass<*>, FirCallableDeclaration<*>>(SourceElementPositioningStrategies.DECLARATION_NAME)
     val MANY_IMPL_MEMBER_NOT_IMPLEMENTED by error2<FirSourceElement, KtClassOrObject, FirClass<*>, FirCallableDeclaration<*>>(SourceElementPositioningStrategies.DECLARATION_NAME)
     val MANY_INTERFACES_MEMBER_NOT_IMPLEMENTED by error2<FirSourceElement, KtClassOrObject, FirClass<*>, FirCallableDeclaration<*>>(SourceElementPositioningStrategies.DECLARATION_NAME)
     val RETURN_TYPE_MISMATCH_ON_OVERRIDE by error2<FirSourceElement, KtNamedDeclaration, FirMemberDeclaration, FirMemberDeclaration>(SourceElementPositioningStrategies.DECLARATION_RETURN_TYPE)

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirNotImplementedOverrideChecker.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
+import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
@@ -17,6 +18,7 @@ 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.*
+import org.jetbrains.kotlin.fir.languageVersionSettings
 import org.jetbrains.kotlin.fir.scopes.unsubstitutedScope
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.types.coneType
@@ -43,6 +45,7 @@ object FirNotImplementedOverrideChecker : FirClassChecker() {
         )
 
         val notImplementedSymbols = mutableListOf<FirCallableSymbol<*>>()
+        val invisibleSymbols = mutableListOf<FirCallableSymbol<*>>()
         val classPackage = declaration.symbol.classId.packageFqName
 
         fun FirCallableMemberDeclaration<*>.isInvisible(): Boolean {
@@ -67,22 +70,25 @@ object FirNotImplementedOverrideChecker : FirClassChecker() {
             classScope.processFunctionsByName(name) { namedFunctionSymbol ->
                 val simpleFunction = namedFunctionSymbol.fir
                 if (!simpleFunction.shouldBeImplemented()) return@processFunctionsByName
-                // TODO: private & package-private functions / properties require another diagnostic
-                // (INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER)
-                if (simpleFunction.isInvisible()) return@processFunctionsByName
-
                 if (declaration.isData && simpleFunction.matchesDataClassSyntheticMemberSignatures) return@processFunctionsByName
 
                 // TODO: suspend function overridden by a Java class in the middle is not properly regarded as an override
                 if (simpleFunction.isSuspend) return@processFunctionsByName
-                notImplementedSymbols += namedFunctionSymbol
+                if (simpleFunction.isInvisible()) {
+                    invisibleSymbols += namedFunctionSymbol
+                } else {
+                    notImplementedSymbols += namedFunctionSymbol
+                }
             }
             classScope.processPropertiesByName(name) { propertySymbol ->
                 val property = propertySymbol.fir as? FirProperty ?: return@processPropertiesByName
                 if (!property.shouldBeImplemented()) return@processPropertiesByName
-                if (property.isInvisible()) return@processPropertiesByName
 
-                notImplementedSymbols += propertySymbol
+                if (property.isInvisible()) {
+                    invisibleSymbols += propertySymbol
+                } else {
+                    notImplementedSymbols += propertySymbol
+                }
             }
         }
 
@@ -94,6 +100,14 @@ object FirNotImplementedOverrideChecker : FirClassChecker() {
                 reporter.reportOn(source, FirErrors.ABSTRACT_CLASS_MEMBER_NOT_IMPLEMENTED, declaration, notImplemented, context)
             }
         }
+        if (invisibleSymbols.isNotEmpty()) {
+            val invisible = invisibleSymbols.first().fir
+            if (context.session.languageVersionSettings.supportsFeature(LanguageFeature.ProhibitInvisibleAbstractMethodsInSuperclasses)) {
+                reporter.reportOn(source, FirErrors.INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER, declaration, invisible, context)
+            } else {
+                reporter.reportOn(source, FirErrors.INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER_WARNING, declaration, invisible, context)
+            }
+        }
     }
 
     private fun FirCallableDeclaration<*>.isFromInterface(context: CheckerContext): Boolean =

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

-// !LANGUAGE: +ProhibitInvisibleAbstractMethodsInSuperclasses
-// FILE: base/Base.java
-package base;
-
-public abstract class Base {
-    public void foo() {
-        packagePrivateFoo();
-    }
-
-    /* package-private */ abstract void packagePrivateFoo();
-}
-
-// FILE: Impl.kt
-package impl
-import base.*
-
-class Impl : Base()
-
-fun foo() {
-    Impl().foo()
-}

compiler/testData/diagnostics/tests/visibility/abstractInvisibleMemberFromJava.kt

+// FIR_IDENTICAL
 // !LANGUAGE: +ProhibitInvisibleAbstractMethodsInSuperclasses
 // FILE: base/Base.java
 package base;

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

@@ -27,9 +27,9 @@ package impl
 import base.*
 import intermediate.*
 
-class ImplDirectFromBase : Base()
+<!INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER!>class ImplDirectFromBase<!> : Base()
 
-object ImplObjDirectFromBase : Base()
+<!INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER!>object ImplObjDirectFromBase<!> : Base()
 
 class ImplDirectFromBaseWithOverride : BaseWithOverride()
 
@@ -37,7 +37,7 @@ class ImplDirectFromBaseWithOverrid : Base() {
     override fun internalFoo(): String = ""
 }
 
-class ImplViaIntermediate : Intermediate()
+<!INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER!>class ImplViaIntermediate<!> : Intermediate()
 
 fun foo() {
     ImplDirectFromBase().foo()

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

-// !LANGUAGE: -ProhibitInvisibleAbstractMethodsInSuperclasses
-// MODULE: base
-// FILE: Base.kt
-package base
-
-abstract class Base {
-    fun foo(): String {
-        return internalFoo()
-    }
-    internal abstract fun internalFoo(): String
-}
-
-// MODULE: impl(base)
-// FILE: Impl.kt
-package impl
-import base.*
-
-class Impl : Base()
-
-fun foo() {
-    Impl().foo()
-}

compiler/testData/diagnostics/tests/visibility/abstractInvisibleMemberFromKotlinWarning.kt

+// FIR_IDENTICAL
 // !LANGUAGE: -ProhibitInvisibleAbstractMethodsInSuperclasses
 // MODULE: base
 // FILE: Base.kt

compiler/tests-spec/testData/diagnostics/linked/declarations/classifier-declaration/class-declaration/abstract-classes/p-2/neg/1.5.fir.kt

@@ -26,7 +26,7 @@ import base.*
 
 // TESTCASE NUMBER: 1
 
-class Case1 : BaseJava() {}
+<!INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER!>class Case1<!> : BaseJava() {}
 
 fun case1() {
     val v = Case1()
@@ -38,7 +38,7 @@ fun case1() {
 */
 abstract class AbstractClassCase2 : BaseJava() {}
 
-class Case2 : AbstractClassCase2() {}
+<!INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER!>class Case2<!> : AbstractClassCase2() {}
 
 fun case2() {
     val v = Case2()

compiler/tests-spec/testData/diagnostics/linked/declarations/classifier-declaration/class-declaration/abstract-classes/p-2/neg/1.6.fir.kt

@@ -51,7 +51,7 @@ fun case2() {
 
 // TESTCASE NUMBER: 3
 
-class Case3 : BaseJava() {}
+<!INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER!>class Case3<!> : BaseJava() {}
 
 fun case3() {
     val v = Case3()
@@ -63,7 +63,7 @@ fun case3() {
 */
 abstract class AbstractClassCase4 : BaseJava() {}
 
-class Case4 : AbstractClassCase4() {}
+<!INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER!>class Case4<!> : AbstractClassCase4() {}
 
 fun case4() {
     val v = Case4()

compiler/tests-spec/testData/diagnostics/linked/declarations/classifier-declaration/class-declaration/abstract-classes/p-2/neg/1.7.fir.kt

@@ -59,7 +59,7 @@ fun case2() {
 
 // TESTCASE NUMBER: 3
 
-class Case3 : BaseKotlin() {}
+<!INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER!>class Case3<!> : BaseKotlin() {}
 
 fun case3() {
     val v = Case3()
@@ -73,7 +73,7 @@ fun case3() {
 */
 abstract class AbstractClassCase4 : BaseKotlin() {}
 
-class Case4 : AbstractClassCase4() {}
+<!INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER!>class Case4<!> : AbstractClassCase4() {}
 
 fun case4() {
     val v = Case4()

compiler/tests-spec/testData/diagnostics/linked/declarations/classifier-declaration/class-declaration/abstract-classes/p-2/neg/1.8.fir.kt

@@ -20,7 +20,7 @@ abstract class AbstractClassCase1() {
     public abstract val pub1: String
 }
 
-class Case1 : AbstractClassCase1(){
+<!INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER!>class Case1<!> : AbstractClassCase1(){
     override fun prot() {}
 
     override fun int() {

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

@@ -896,6 +896,22 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirErrors.INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER) { firDiagnostic ->
+        InvisibleAbstractMemberFromSuperImpl(
+            firSymbolBuilder.buildClassLikeSymbol(firDiagnostic.a),
+            firSymbolBuilder.buildCallableSymbol(firDiagnostic.b as FirCallableDeclaration),
+            firDiagnostic as FirPsiDiagnostic<*>,
+            token,
+        )
+    }
+    add(FirErrors.INVISIBLE_ABSTRACT_MEMBER_FROM_SUPER_WARNING) { firDiagnostic ->
+        InvisibleAbstractMemberFromSuperWarningImpl(
+            firSymbolBuilder.buildClassLikeSymbol(firDiagnostic.a),
+            firSymbolBuilder.buildCallableSymbol(firDiagnostic.b as FirCallableDeclaration),
+            firDiagnostic as FirPsiDiagnostic<*>,
+            token,
+        )
+    }
     add(FirErrors.MANY_IMPL_MEMBER_NOT_IMPLEMENTED) { firDiagnostic ->
         ManyImplMemberNotImplementedImpl(
             firSymbolBuilder.buildClassLikeSymbol(firDiagnostic.a),

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

@@ -637,6 +637,18 @@ sealed class KtFirDiagnostic<PSI: PsiElement> : KtDiagnosticWithPsi<PSI> {
         abstract val missingDeclaration: KtCallableSymbol
     }
 
+    abstract class InvisibleAbstractMemberFromSuper : KtFirDiagnostic<KtClassOrObject>() {
+        override val diagnosticClass get() = InvisibleAbstractMemberFromSuper::class
+        abstract val classOrObject: KtClassLikeSymbol
+        abstract val invisibleDeclaration: KtCallableSymbol
+    }
+
+    abstract class InvisibleAbstractMemberFromSuperWarning : KtFirDiagnostic<KtClassOrObject>() {
+        override val diagnosticClass get() = InvisibleAbstractMemberFromSuperWarning::class
+        abstract val classOrObject: KtClassLikeSymbol
+        abstract val invisibleDeclaration: KtCallableSymbol
+    }
+
     abstract class ManyImplMemberNotImplemented : KtFirDiagnostic<KtClassOrObject>() {
         override val diagnosticClass get() = ManyImplMemberNotImplemented::class
         abstract val classOrObject: KtClassLikeSymbol

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

@@ -1025,6 +1025,24 @@ internal class AbstractClassMemberNotImplementedImpl(
     override val firDiagnostic: FirPsiDiagnostic<*> by weakRef(firDiagnostic)
 }
 
+internal class InvisibleAbstractMemberFromSuperImpl(
+    override val classOrObject: KtClassLikeSymbol,
+    override val invisibleDeclaration: KtCallableSymbol,
+    firDiagnostic: FirPsiDiagnostic<*>,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.InvisibleAbstractMemberFromSuper(), KtAbstractFirDiagnostic<KtClassOrObject> {
+    override val firDiagnostic: FirPsiDiagnostic<*> by weakRef(firDiagnostic)
+}
+
+internal class InvisibleAbstractMemberFromSuperWarningImpl(
+    override val classOrObject: KtClassLikeSymbol,
+    override val invisibleDeclaration: KtCallableSymbol,
+    firDiagnostic: FirPsiDiagnostic<*>,
+    override val token: ValidityToken,
+) : KtFirDiagnostic.InvisibleAbstractMemberFromSuperWarning(), KtAbstractFirDiagnostic<KtClassOrObject> {
+    override val firDiagnostic: FirPsiDiagnostic<*> by weakRef(firDiagnostic)
+}
+
 internal class ManyImplMemberNotImplementedImpl(
     override val classOrObject: KtClassLikeSymbol,
     override val missingDeclaration: KtCallableSymbol,