[FIR] Don't miss VIRTUAL_MEMBER_HIDDEN

^KT-59925 Fixed

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

@@ -12,6 +12,8 @@ import com.intellij.util.diff.FlyweightCapableTreeStructure
 import org.jetbrains.kotlin.*
 import org.jetbrains.kotlin.diagnostics.valOrVarKeyword
 import org.jetbrains.kotlin.fir.FirElement
+import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
+import org.jetbrains.kotlin.fir.symbols.SymbolInternals
 import org.jetbrains.kotlin.lexer.KtKeywordToken
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -101,6 +103,9 @@ fun FirElement.getModifier(token: KtModifierKeywordToken): FirModifier<*>? = sou
 
 fun FirElement.hasModifier(token: KtModifierKeywordToken): Boolean = token in source.getModifierList()
 
+@OptIn(SymbolInternals::class)
+fun FirBasedSymbol<*>.hasModifier(token: KtModifierKeywordToken): Boolean = fir.hasModifier(token)
+
 internal val KtSourceElement?.valOrVarKeyword: KtKeywordToken?
     get() = when (this) {
         null -> null

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

@@ -16,6 +16,7 @@ import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.checkers.expression.FirOptInUsageBaseChecker
 import org.jetbrains.kotlin.fir.analysis.checkers.expression.FirOptInUsageBaseChecker.Experimentality
 import org.jetbrains.kotlin.fir.analysis.checkers.getContainingClassSymbol
+import org.jetbrains.kotlin.fir.analysis.checkers.hasModifier
 import org.jetbrains.kotlin.fir.analysis.checkers.unsubstitutedScope
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.analysis.overridesBackwardCompatibilityHelper
@@ -37,6 +38,7 @@ import org.jetbrains.kotlin.fir.symbols.lazyResolveToPhase
 import org.jetbrains.kotlin.fir.symbols.impl.*
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.visibilityChecker
+import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.types.AbstractTypeChecker
 import org.jetbrains.kotlin.types.TypeCheckerState
 
@@ -250,8 +252,9 @@ object FirOverrideChecker : FirClassChecker() {
         context: CheckerContext
     ) {
         val overriddenMemberSymbols = firTypeScope.retrieveDirectOverriddenOf(member)
+        val hasOverrideKeyword = member.hasModifier(KtTokens.OVERRIDE_KEYWORD)
 
-        if (!member.isOverride) {
+        if (!member.isOverride || !hasOverrideKeyword) {
             if (overriddenMemberSymbols.isEmpty() ||
                 context.session.overridesBackwardCompatibilityHelper.overrideCanBeOmitted(overriddenMemberSymbols, context)
             ) {

compiler/testData/diagnostics/tests/override/Generics.fir.kt

@@ -23,8 +23,8 @@ open class MyGenericClass<T>(t : T) : MyTrait<T>, MyAbstractClass<T>(), MyProps<
 class MyChildClass() : MyGenericClass<Int>(1) {}
 class MyChildClass1<T>(t : T) : MyGenericClass<T>(t) {}
 class MyChildClass2<T>(t : T) : MyGenericClass<T>(t) {
-    fun foo(t: T) = t
-    val pr : T = t
+    fun <!VIRTUAL_MEMBER_HIDDEN!>foo<!>(t: T) = t
+    val <!VIRTUAL_MEMBER_HIDDEN!>pr<!> : T = t
     override fun bar(t: T) = t
     override val p : T = t
 }

compiler/testData/diagnostics/tests/override/NonGenerics.fir.kt

@@ -1,50 +0,0 @@
-package override.normal
-
-interface MyTrait {
-    fun foo()
-    val pr : Unit
-}
-
-abstract class MyAbstractClass {
-    abstract fun bar()
-    abstract val prr : Unit
-
-}
-
-open class MyClass() : MyTrait, MyAbstractClass() {
-    override fun foo() {}
-    override fun bar() {}
-
-    override val pr : Unit = Unit
-    override val prr : Unit = Unit
-}
-
-class MyChildClass() : MyClass() {}
-
-<!ABSTRACT_CLASS_MEMBER_NOT_IMPLEMENTED!>class MyIllegalClass<!> : MyTrait, MyAbstractClass() {}
-
-<!ABSTRACT_CLASS_MEMBER_NOT_IMPLEMENTED!>class MyIllegalClass2<!>() : MyTrait, MyAbstractClass() {
-    override fun foo() {}
-    override val pr : Unit = Unit
-    override val prr : Unit = Unit
-}
-
-<!ABSTRACT_MEMBER_NOT_IMPLEMENTED!>class MyIllegalClass3<!>() : MyTrait, MyAbstractClass() {
-    override fun bar() {}
-    override val pr : Unit = Unit
-    override val prr : Unit = Unit
-}
-
-<!ABSTRACT_CLASS_MEMBER_NOT_IMPLEMENTED!>class MyIllegalClass4<!>() : MyTrait, MyAbstractClass() {
-    fun <!VIRTUAL_MEMBER_HIDDEN!>foo<!>() {}
-    <!MUST_BE_INITIALIZED_OR_BE_ABSTRACT!>val <!VIRTUAL_MEMBER_HIDDEN!>pr<!> : Unit<!>
-    <!NOTHING_TO_OVERRIDE!>override<!> fun other() {}
-    <!NOTHING_TO_OVERRIDE!>override<!> val otherPr : Int = 1
-}
-
-class MyChildClass1() : MyClass() {
-    fun foo() {}
-    val pr : Unit = Unit
-    override fun bar() {}
-    override val prr : Unit = Unit
-}

compiler/testData/diagnostics/tests/override/NonGenerics.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 package override.normal
 
 interface MyTrait {