[FIR] Don't lose error level enhancements in warning-level-enhanced arguments

The error-level enhancement is kept as warning-level and a new
LanguageFeature is introduced to turn the warning into an error.

#KT-63208 Fixed
#KT-63209

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

@@ -5091,6 +5091,7 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
         ReceiverNullabilityMismatchBasedOnJavaAnnotationsImpl(
             firSymbolBuilder.typeBuilder.buildKtType(firDiagnostic.a),
             firSymbolBuilder.typeBuilder.buildKtType(firDiagnostic.b),
+            firDiagnostic.c,
             firDiagnostic as KtPsiDiagnostic,
             token,
         )
@@ -5099,6 +5100,7 @@ internal val KT_DIAGNOSTIC_CONVERTER = KtDiagnosticConverterBuilder.buildConvert
         NullabilityMismatchBasedOnJavaAnnotationsImpl(
             firSymbolBuilder.typeBuilder.buildKtType(firDiagnostic.a),
             firSymbolBuilder.typeBuilder.buildKtType(firDiagnostic.b),
+            firDiagnostic.c,
             firDiagnostic as KtPsiDiagnostic,
             token,
         )

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

@@ -3544,12 +3544,14 @@ sealed interface KtFirDiagnostic<PSI : PsiElement> : KtDiagnosticWithPsi<PSI> {
         override val diagnosticClass get() = ReceiverNullabilityMismatchBasedOnJavaAnnotations::class
         val actualType: KtType
         val expectedType: KtType
+        val messageSuffix: String
     }
 
     interface NullabilityMismatchBasedOnJavaAnnotations : KtFirDiagnostic<PsiElement> {
         override val diagnosticClass get() = NullabilityMismatchBasedOnJavaAnnotations::class
         val actualType: KtType
         val expectedType: KtType
+        val messageSuffix: String
     }
 
     interface UpperBoundCannotBeArray : KtFirDiagnostic<PsiElement> {

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

@@ -4274,6 +4274,7 @@ internal class JavaTypeMismatchImpl(
 internal class ReceiverNullabilityMismatchBasedOnJavaAnnotationsImpl(
     override val actualType: KtType,
     override val expectedType: KtType,
+    override val messageSuffix: String,
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<PsiElement>(firDiagnostic, token), KtFirDiagnostic.ReceiverNullabilityMismatchBasedOnJavaAnnotations
@@ -4281,6 +4282,7 @@ internal class ReceiverNullabilityMismatchBasedOnJavaAnnotationsImpl(
 internal class NullabilityMismatchBasedOnJavaAnnotationsImpl(
     override val actualType: KtType,
     override val expectedType: KtType,
+    override val messageSuffix: String,
     firDiagnostic: KtPsiDiagnostic,
     token: KtLifetimeToken,
 ) : KtAbstractFirDiagnostic<PsiElement>(firDiagnostic, token), KtFirDiagnostic.NullabilityMismatchBasedOnJavaAnnotations

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

@@ -68,6 +68,18 @@ public class FirPsiOldFrontendForeignAnnotationsCompiledJavaTestGenerated extend
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/eclipse.kt");
         }
 
+        @Test
+        @TestMetadata("errorArgumentOfWarningAfter.kt")
+        public void testErrorArgumentOfWarningAfter() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningAfter.kt");
+        }
+
+        @Test
+        @TestMetadata("errorArgumentOfWarningBefore.kt")
+        public void testErrorArgumentOfWarningBefore() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningBefore.kt");
+        }
+
         @Test
         @TestMetadata("findBugsSimple.kt")
         public void testFindBugsSimple() throws Exception {

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

@@ -68,6 +68,18 @@ public class FirPsiOldFrontendForeignAnnotationsCompiledJavaWithPsiClassReadingT
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/eclipse.kt");
         }
 
+        @Test
+        @TestMetadata("errorArgumentOfWarningAfter.kt")
+        public void testErrorArgumentOfWarningAfter() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningAfter.kt");
+        }
+
+        @Test
+        @TestMetadata("errorArgumentOfWarningBefore.kt")
+        public void testErrorArgumentOfWarningBefore() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningBefore.kt");
+        }
+
         @Test
         @TestMetadata("findBugsSimple.kt")
         public void testFindBugsSimple() throws Exception {

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

@@ -68,6 +68,18 @@ public class FirPsiOldFrontendForeignAnnotationsSourceJavaTestGenerated extends
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/eclipse.kt");
         }
 
+        @Test
+        @TestMetadata("errorArgumentOfWarningAfter.kt")
+        public void testErrorArgumentOfWarningAfter() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningAfter.kt");
+        }
+
+        @Test
+        @TestMetadata("errorArgumentOfWarningBefore.kt")
+        public void testErrorArgumentOfWarningBefore() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningBefore.kt");
+        }
+
         @Test
         @TestMetadata("findBugsSimple.kt")
         public void testFindBugsSimple() throws Exception {

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

@@ -56,10 +56,12 @@ object JVM_DIAGNOSTICS_LIST : DiagnosticList("FirJvmErrors") {
         val RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS by warning<PsiElement> {
             parameter<ConeKotlinType>("actualType")
             parameter<ConeKotlinType>("expectedType")
+            parameter<String>("messageSuffix")
         }
         val NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS by warning<PsiElement> {
             parameter<ConeKotlinType>("actualType")
             parameter<ConeKotlinType>("expectedType")
+            parameter<String>("messageSuffix")
         }
     }
 

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

@@ -15,6 +15,7 @@ import org.jetbrains.kotlin.diagnostics.*
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactory0
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactory1
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactory2
+import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactory3
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactoryForDeprecation0
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactoryForDeprecation2
 import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactoryForDeprecation4
@@ -52,8 +53,8 @@ object FirJvmErrors {
 
     // Types
     val JAVA_TYPE_MISMATCH: KtDiagnosticFactory2<ConeKotlinType, ConeKotlinType> by error2<KtExpression, ConeKotlinType, ConeKotlinType>()
-    val RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS: KtDiagnosticFactory2<ConeKotlinType, ConeKotlinType> by warning2<PsiElement, ConeKotlinType, ConeKotlinType>()
-    val NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS: KtDiagnosticFactory2<ConeKotlinType, ConeKotlinType> by warning2<PsiElement, ConeKotlinType, ConeKotlinType>()
+    val RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS: KtDiagnosticFactory3<ConeKotlinType, ConeKotlinType, String> by warning3<PsiElement, ConeKotlinType, ConeKotlinType, String>()
+    val NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS: KtDiagnosticFactory3<ConeKotlinType, ConeKotlinType, String> by warning3<PsiElement, ConeKotlinType, ConeKotlinType, String>()
 
     // Type parameters
     val UPPER_BOUND_CANNOT_BE_ARRAY: KtDiagnosticFactory0 by error0<PsiElement>()

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

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.diagnostics.rendering.BaseDiagnosticRendererFactory
 import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers.NAME
 import org.jetbrains.kotlin.diagnostics.rendering.CommonRenderers.STRING
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.DECLARATION_NAME
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.OPTIONAL_SENTENCE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.RENDER_TYPE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnosticRenderers.SYMBOL
 import org.jetbrains.kotlin.fir.analysis.diagnostics.jvm.FirJvmErrors.CONCURRENT_HASH_MAP_CONTAINS_OPERATOR
@@ -94,15 +95,17 @@ object FirJvmErrorsDefaultMessages : BaseDiagnosticRendererFactory() {
 
         map.put(
             NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS,
-            "Java type mismatch: inferred type is ''{1}'', but ''{0}'' was expected.",
+            "Java type mismatch: inferred type is ''{1}'', but ''{0}'' was expected.{2}",
             RENDER_TYPE,
-            RENDER_TYPE
+            RENDER_TYPE,
+            OPTIONAL_SENTENCE,
         )
         map.put(
             RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS,
-            "Only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable receiver of type ''{0}''.",
+            "Only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable receiver of type ''{0}''.{2}",
             RENDER_TYPE,
-            NOT_RENDERED
+            NOT_RENDERED,
+            OPTIONAL_SENTENCE,
         )
 
         map.put(

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

@@ -5,8 +5,9 @@
 
 package org.jetbrains.kotlin.fir.analysis.jvm.checkers.expression
 
+import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
-import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactory2
+import org.jetbrains.kotlin.diagnostics.KtDiagnosticFactory3
 import org.jetbrains.kotlin.diagnostics.reportOn
 import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
@@ -15,11 +16,11 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.jvm.FirJvmErrors
 import org.jetbrains.kotlin.fir.expressions.*
 import org.jetbrains.kotlin.fir.expressions.impl.FirElseIfTrueCondition
 import org.jetbrains.kotlin.fir.java.enhancement.EnhancedForWarningConeSubstitutor
+import org.jetbrains.kotlin.fir.java.enhancement.isEnhancedTypeForWarningDeprecation
 import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutor
 import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutorByMap
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.types.*
-import java.util.*
 
 // TODO reimplement using AdditionalTypeChecker KT-62864
 object FirQualifiedAccessJavaNullabilityWarningChecker : FirQualifiedAccessExpressionChecker() {
@@ -142,7 +143,7 @@ internal fun FirExpression.checkExpressionForEnhancedTypeMismatch(
     expectedType: ConeKotlinType?,
     reporter: DiagnosticReporter,
     context: CheckerContext,
-    factory: KtDiagnosticFactory2<ConeKotlinType, ConeKotlinType>,
+    factory: KtDiagnosticFactory3<ConeKotlinType, ConeKotlinType, String>,
 ) {
     if (expectedType == null) return
     val actualType = resolvedType
@@ -154,7 +155,14 @@ internal fun FirExpression.checkExpressionForEnhancedTypeMismatch(
         // Don't report anything if the original types didn't match.
         actualType.isSubtypeOf(context.session.typeContext, expectedType)
     ) {
-        reporter.reportOn(source, factory, actualTypeForComparison, expectedTypeForComparison, context)
+        val suffix =
+            if (actualType.isEnhancedTypeForWarningDeprecation || expectedType.isEnhancedTypeForWarningDeprecation) {
+                val versionString = LanguageFeature.SupportJavaErrorEnhancementOfArgumentsOfWarningLevelEnhanced.sinceVersion?.versionString
+                "This will become an error in Kotlin $versionString. See https://youtrack.jetbrains.com/issue/KT-63209"
+            } else {
+                ""
+            }
+        reporter.reportOn(source, factory, actualTypeForComparison, expectedTypeForComparison, suffix, context)
     }
 }
 

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/enhancement/EnhancedTypeForWarningAttribute.kt

@@ -12,13 +12,14 @@ import kotlin.reflect.KClass
 
 class EnhancedTypeForWarningAttribute(
     override val coneType: ConeKotlinType,
+    val isDeprecation: Boolean,
 ) : ConeAttributeWithConeType<EnhancedTypeForWarningAttribute>() {
     override fun union(other: EnhancedTypeForWarningAttribute?): EnhancedTypeForWarningAttribute? = null
     override fun intersect(other: EnhancedTypeForWarningAttribute?): EnhancedTypeForWarningAttribute? = null
     override fun add(other: EnhancedTypeForWarningAttribute?): EnhancedTypeForWarningAttribute = other ?: this
     override fun isSubtypeOf(other: EnhancedTypeForWarningAttribute?): Boolean = true
     override fun toString(): String = "Enhanced for warning(${coneType.renderForDebugging()})"
-    override fun copyWith(newType: ConeKotlinType): EnhancedTypeForWarningAttribute = EnhancedTypeForWarningAttribute(newType)
+    override fun copyWith(newType: ConeKotlinType): EnhancedTypeForWarningAttribute = EnhancedTypeForWarningAttribute(newType, isDeprecation)
 
     override val key: KClass<out EnhancedTypeForWarningAttribute>
         get() = EnhancedTypeForWarningAttribute::class
@@ -36,12 +37,14 @@ class EnhancedTypeForWarningAttribute(
         other as EnhancedTypeForWarningAttribute
 
         if (coneType != other.coneType) return false
+        if (isDeprecation != other.isDeprecation) return false
 
         return true
     }
 
     override fun hashCode(): Int {
         var result = coneType.hashCode()
+        result = 31 * result + isDeprecation.hashCode()
         return result
     }
 }
@@ -51,6 +54,9 @@ val ConeAttributes.enhancedTypeForWarning: EnhancedTypeForWarningAttribute? by C
 val ConeKotlinType.enhancedTypeForWarning: ConeKotlinType?
     get() = attributes.enhancedTypeForWarning?.coneType
 
+val ConeKotlinType.isEnhancedTypeForWarningDeprecation: Boolean
+    get() = attributes.enhancedTypeForWarning?.isDeprecation == true
+
 /**
  * Substitutor that substitutes types with their [ConeKotlinType.enhancedTypeForWarning] recursively.
  */

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/enhancement/javaTypeUtils.kt

@@ -6,7 +6,9 @@
 package org.jetbrains.kotlin.fir.java.enhancement
 
 import org.jetbrains.kotlin.builtins.jvm.JavaToKotlinClassMap
+import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.languageVersionSettings
 import org.jetbrains.kotlin.fir.symbols.ConeClassLikeLookupTag
 import org.jetbrains.kotlin.fir.symbols.ConeClassifierLookupTag
 import org.jetbrains.kotlin.fir.types.*
@@ -15,7 +17,7 @@ import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.utils.addToStdlib.applyIf
 
 internal fun ConeKotlinType.enhance(session: FirSession, qualifiers: IndexedJavaTypeQualifiers): ConeKotlinType? =
-    enhanceConeKotlinType(session, qualifiers, 0, mutableListOf<Int>().apply { computeSubtreeSizes(this) })
+    enhanceConeKotlinType(session, qualifiers, 0, mutableListOf<Int>().apply { computeSubtreeSizes(this) }, convertErrorsToWarnings = false)
 
 // The index in the lambda is the position of the type component in a depth-first walk of the tree.
 // Example: A<B<C, D>, E<F>> - 0<1<2, 3>, 4<5>>. For flexible types, some arguments in the lower bound
@@ -37,7 +39,8 @@ private fun ConeKotlinType.enhanceConeKotlinType(
     session: FirSession,
     qualifiers: IndexedJavaTypeQualifiers,
     index: Int,
-    subtreeSizes: List<Int>
+    subtreeSizes: List<Int>,
+    convertErrorsToWarnings: Boolean,
 ): ConeKotlinType? {
     return when (this) {
         is ConeFlexibleType -> {
@@ -46,10 +49,12 @@ private fun ConeKotlinType.enhanceConeKotlinType(
             // It's not totally correct, but tolerable since we would like to avoid excessive breaking changes and the warnings should be
             // anyway reported.
             val lowerResult = lowerBound.enhanceInflexibleType(
-                session, TypeComponentPosition.FLEXIBLE_LOWER, qualifiers, index, subtreeSizes
+                session, TypeComponentPosition.FLEXIBLE_LOWER, qualifiers, index, subtreeSizes,
+                isFromDefinitelyNotNullType = false, convertErrorToWarning = convertErrorsToWarnings,
             )
             val upperResult = upperBound.enhanceInflexibleType(
-                session, TypeComponentPosition.FLEXIBLE_UPPER, qualifiers, index, subtreeSizes
+                session, TypeComponentPosition.FLEXIBLE_UPPER, qualifiers, index, subtreeSizes,
+                isFromDefinitelyNotNullType = false, convertErrorToWarning = convertErrorsToWarnings,
             )
 
             when {
@@ -59,7 +64,8 @@ private fun ConeKotlinType.enhanceConeKotlinType(
             }
         }
         is ConeSimpleKotlinType -> enhanceInflexibleType(
-            session, TypeComponentPosition.INFLEXIBLE, qualifiers, index, subtreeSizes
+            session, TypeComponentPosition.INFLEXIBLE, qualifiers, index, subtreeSizes,
+            isFromDefinitelyNotNullType = false, convertErrorToWarning = convertErrorsToWarnings,
         )
         else -> null
     }
@@ -79,10 +85,11 @@ private fun ConeSimpleKotlinType.enhanceInflexibleType(
     qualifiers: IndexedJavaTypeQualifiers,
     index: Int,
     subtreeSizes: List<Int>,
-    isFromDefinitelyNotNullType: Boolean = false,
+    isFromDefinitelyNotNullType: Boolean,
+    convertErrorToWarning: Boolean,
 ): ConeSimpleKotlinType? {
     if (this is ConeDefinitelyNotNullType) {
-        return original.enhanceInflexibleType(session, position, qualifiers, index, subtreeSizes, isFromDefinitelyNotNullType = true)
+        return original.enhanceInflexibleType(session, position, qualifiers, index, subtreeSizes, isFromDefinitelyNotNullType = true, convertErrorToWarning)
     }
 
     val shouldEnhance = position.shouldEnhance()
@@ -103,19 +110,20 @@ private fun ConeSimpleKotlinType.enhanceInflexibleType(
         isFromDefinitelyNotNullType,
         effectiveQualifiers.definitelyNotNull,
         nullabilityFromQualifiers,
-        enhancedTag
+        enhancedTag,
+        convertNestedErrorsToWarnings = convertErrorToWarning ||
+                effectiveQualifiers.isNullabilityQualifierForWarning &&
+                !session.languageVersionSettings.supportsFeature(LanguageFeature.SupportJavaErrorEnhancementOfArgumentsOfWarningLevelEnhanced),
     )
 
-    return if (effectiveQualifiers.isNullabilityQualifierForWarning && enhanced != null) {
-        val newAttributes = attributes.plus(EnhancedTypeForWarningAttribute(enhanced))
+    return if (enhanced != null && (effectiveQualifiers.isNullabilityQualifierForWarning || convertErrorToWarning)) {
+        val newAttributes = attributes.plus(EnhancedTypeForWarningAttribute(enhanced, isDeprecation = convertErrorToWarning && effectiveQualifiers.enhancesSomethingForError()))
 
-        // TODO if the arguments of `enhanced` are error-level annotated, we're losing them here for compatibility with K1,
-        // a fix requires a deprecation cycle, see KT-63208
         if (enhancedTag != lookupTag) {
             // Handle case when mutability was enhanced and nullability was enhanced for warning.
-            enhancedTag.constructType(typeArguments, isNullable, newAttributes)
+            enhancedTag.constructType(enhanced.typeArguments, isNullable, newAttributes)
         } else {
-            this.withAttributes(newAttributes)
+            this.withAttributes(newAttributes).withArguments(enhanced.typeArguments)
         }.applyIf(isFromDefinitelyNotNullType) {
             // If the original type was DNN, we need to wrap the result in a DNN type because `this` is the non-DNN part of the original.
             // In the non-warning case, this happens in the nested call and so `enhanced` is already DNN.
@@ -126,6 +134,10 @@ private fun ConeSimpleKotlinType.enhanceInflexibleType(
     }
 }
 
+private fun JavaTypeQualifiers.enhancesSomethingForError(): Boolean {
+    return !isNullabilityQualifierForWarning && (nullability != null || mutability != null || definitelyNotNull)
+}
+
 private fun ConeLookupTagBasedType.enhanceInflexibleType(
     session: FirSession,
     qualifiers: IndexedJavaTypeQualifiers,
@@ -135,6 +147,7 @@ private fun ConeLookupTagBasedType.enhanceInflexibleType(
     isDefinitelyNotNull: Boolean,
     nullabilityFromQualifiers: NullabilityQualifier?,
     enhancedTag: ConeClassifierLookupTag,
+    convertNestedErrorsToWarnings: Boolean,
 ): ConeSimpleKotlinType? {
     val enhancedIsNullable = when (nullabilityFromQualifiers) {
         NullabilityQualifier.NULLABLE -> true
@@ -145,14 +158,15 @@ private fun ConeLookupTagBasedType.enhanceInflexibleType(
     var globalArgIndex = index + 1
     val enhancedArguments = typeArguments.map { arg ->
         val argIndex = globalArgIndex.also { globalArgIndex += subtreeSizes[it] }
-        arg.type?.enhanceConeKotlinType(session, qualifiers, argIndex, subtreeSizes)?.let {
-            when (arg.kind) {
-                ProjectionKind.IN -> ConeKotlinTypeProjectionIn(it)
-                ProjectionKind.OUT -> ConeKotlinTypeProjectionOut(it)
-                ProjectionKind.STAR -> ConeStarProjection
-                ProjectionKind.INVARIANT -> it
+        arg.type?.enhanceConeKotlinType(session, qualifiers, argIndex, subtreeSizes, convertErrorsToWarnings = convertNestedErrorsToWarnings)
+            ?.let {
+                when (arg.kind) {
+                    ProjectionKind.IN -> ConeKotlinTypeProjectionIn(it)
+                    ProjectionKind.OUT -> ConeKotlinTypeProjectionOut(it)
+                    ProjectionKind.STAR -> ConeStarProjection
+                    ProjectionKind.INVARIANT -> it
+                }
             }
-        }
     }
 
     val shouldAddAttribute = nullabilityFromQualifiers == NullabilityQualifier.NOT_NULL && !hasEnhancedNullability

compiler/testData/diagnostics/foreignAnnotationsTests/java8Tests/warningModeForHeadType.fir.kt

@@ -0,0 +1,39 @@
+// FULL_JDK
+// !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_PARAMETER
+// LANGUAGE: -SupportJavaErrorEnhancementOfArgumentsOfWarningLevelEnhanced
+
+// FILE: ElementTypesAreNonnullByDefault.java
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import javax.annotation.Nonnull;
+import javax.annotation.meta.TypeQualifierDefault;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.TYPE})
+@TypeQualifierDefault({ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER})
+@Nonnull
+@interface ElementTypesAreNonnullByDefault {
+}
+
+// FILE: Maps.java
+import org.checkerframework.checker.nullness.qual.Nullable;
+// Here it's important that @ElementTypesAreNonnullByDefault is a JSR-305 default qualifier and disabled by default (resulting in warnings-only)
+// Thus return type (head type) is considered as warningly-annotated as not-nullable and that makes annotations on bounds for K and V
+// be effectively ignored on non-warnings level.
+// Behavior was changed in K2, see KT-63209.
+@ElementTypesAreNonnullByDefault
+public final class Maps {
+    public static <K extends @Nullable Object, V extends @Nullable Object> java.util.HashMap<K,V> newHashMap() { return null; }
+}
+
+// FILE: main.kt
+
+fun foo() {
+    val x = Maps.newHashMap<String, Int>()
+    x.put("", 1)
+    // If there were no @ElementTypesAreNonnullByDefault on the Maps class, there would be an error on `null` argument because the type of `x`
+    // would be `HashMap<String, Int>!`, i.e. with non-flexible type arguments, thus not allowing nulls.
+    x.put("", <!NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>null<!>)
+}

compiler/testData/diagnostics/foreignAnnotationsTests/java8Tests/warningModeForHeadType.kt

@@ -1,6 +1,6 @@
-// FIR_IDENTICAL
 // FULL_JDK
 // !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_PARAMETER
+// LANGUAGE: -SupportJavaErrorEnhancementOfArgumentsOfWarningLevelEnhanced
 
 // FILE: ElementTypesAreNonnullByDefault.java
 import java.lang.annotation.ElementType;
@@ -22,6 +22,7 @@ import org.checkerframework.checker.nullness.qual.Nullable;
 // Here it's important that @ElementTypesAreNonnullByDefault is a JSR-305 default qualifier and disabled by default (resulting in warnings-only)
 // Thus return type (head type) is considered as warningly-annotated as not-nullable and that makes annotations on bounds for K and V
 // be effectively ignored on non-warnings level.
+// Behavior was changed in K2, see KT-63209.
 @ElementTypesAreNonnullByDefault
 public final class Maps {
     public static <K extends @Nullable Object, V extends @Nullable Object> java.util.HashMap<K,V> newHashMap() { return null; }

compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningAfter.fir.kt

@@ -0,0 +1,71 @@
+// NULLABILITY_ANNOTATIONS: @io.reactivex.rxjava3.annotations:strict, @org.eclipse.jdt.annotation:warn
+// LANGUAGE: +SupportJavaErrorEnhancementOfArgumentsOfWarningLevelEnhanced
+// SOURCE_RETENTION_ANNOTATIONS
+// MUTE_FOR_PSI_CLASS_FILES_READING
+// ^because annotations don't allow type parameter use.
+// ISSUE: KT-63209
+
+// FILE: A1.java
+import java.util.List;
+
+public class A1 {
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable String> warningError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable List<@io.reactivex.rxjava3.annotations.Nullable String>> warningErrorError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@org.eclipse.jdt.annotation.Nullable List<@io.reactivex.rxjava3.annotations.Nullable String>> warningWarningError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable List<@org.eclipse.jdt.annotation.Nullable String>> warningErrorWarning() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<List<@io.reactivex.rxjava3.annotations.Nullable String>> warningPlatformError() {
+        return null;
+    }
+}
+
+// FILE: main.kt
+fun main1() {
+    val list = A1.warningError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element<!UNSAFE_CALL!>.<!>length
+}
+
+fun main2() {
+    val list = A1.warningErrorError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element<!UNSAFE_CALL!>.<!>get(0)
+    element!!.get(0)<!UNSAFE_CALL!>.<!>length
+}
+
+fun main3() {
+    val list = A1.warningWarningError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>element<!>.get(0)
+    element!!.get(0)<!UNSAFE_CALL!>.<!>length
+}
+
+fun main4() {
+    val list = A1.warningErrorWarning()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element<!UNSAFE_CALL!>.<!>get(0)
+    <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>element!!.get(0)<!>.length
+}
+
+fun main5() {
+    val list = A1.warningPlatformError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element.get(0)
+    element!!.get(0)<!UNSAFE_CALL!>.<!>length
+}

compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningAfter.kt

@@ -0,0 +1,71 @@
+// NULLABILITY_ANNOTATIONS: @io.reactivex.rxjava3.annotations:strict, @org.eclipse.jdt.annotation:warn
+// LANGUAGE: +SupportJavaErrorEnhancementOfArgumentsOfWarningLevelEnhanced
+// SOURCE_RETENTION_ANNOTATIONS
+// MUTE_FOR_PSI_CLASS_FILES_READING
+// ^because annotations don't allow type parameter use.
+// ISSUE: KT-63209
+
+// FILE: A1.java
+import java.util.List;
+
+public class A1 {
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable String> warningError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable List<@io.reactivex.rxjava3.annotations.Nullable String>> warningErrorError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@org.eclipse.jdt.annotation.Nullable List<@io.reactivex.rxjava3.annotations.Nullable String>> warningWarningError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable List<@org.eclipse.jdt.annotation.Nullable String>> warningErrorWarning() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<List<@io.reactivex.rxjava3.annotations.Nullable String>> warningPlatformError() {
+        return null;
+    }
+}
+
+// FILE: main.kt
+fun main1() {
+    val list = A1.warningError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element.length
+}
+
+fun main2() {
+    val list = A1.warningErrorError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element.get(0)
+    element!!.get(0).length
+}
+
+fun main3() {
+    val list = A1.warningWarningError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element.get(0)
+    element!!.get(0).length
+}
+
+fun main4() {
+    val list = A1.warningErrorWarning()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element.get(0)
+    element!!.get(0).length
+}
+
+fun main5() {
+    val list = A1.warningPlatformError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element.get(0)
+    element!!.get(0).length
+}

compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningBefore.fir.kt

@@ -0,0 +1,71 @@
+// NULLABILITY_ANNOTATIONS: @io.reactivex.rxjava3.annotations:strict, @org.eclipse.jdt.annotation:warn
+// LANGUAGE: -SupportJavaErrorEnhancementOfArgumentsOfWarningLevelEnhanced
+// SOURCE_RETENTION_ANNOTATIONS
+// MUTE_FOR_PSI_CLASS_FILES_READING
+// ^because annotations don't allow type parameter use.
+// ISSUE: KT-63209
+
+// FILE: A1.java
+import java.util.List;
+
+public class A1 {
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable String> warningError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable List<@io.reactivex.rxjava3.annotations.Nullable String>> warningErrorError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@org.eclipse.jdt.annotation.Nullable List<@io.reactivex.rxjava3.annotations.Nullable String>> warningWarningError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable List<@org.eclipse.jdt.annotation.Nullable String>> warningErrorWarning() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<List<@io.reactivex.rxjava3.annotations.Nullable String>> warningPlatformError() {
+        return null;
+    }
+}
+
+// FILE: main.kt
+fun main1() {
+    val list = A1.warningError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("kotlin.collections.(Mutable)List<@Nullable() kotlin.String?>?")!>list<!>.get(0)
+    <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("@Nullable() kotlin.String?;  This will become an error in Kotlin 2.1. See https://youtrack.jetbrains.com/issue/KT-63209.")!>element<!>.length
+}
+
+fun main2() {
+    val list = A1.warningErrorError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("kotlin.collections.(Mutable)List<(@Nullable() kotlin.collections.MutableList<@Nullable() kotlin.String?>?..@Nullable() kotlin.collections.List<@Nullable() kotlin.String?>?)>?")!>list<!>.get(0)
+    <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("(@Nullable() kotlin.collections.MutableList<@Nullable() kotlin.String?>?..@Nullable() kotlin.collections.List<@Nullable() kotlin.String?>?);  This will become an error in Kotlin 2.1. See https://youtrack.jetbrains.com/issue/KT-63209.")!>element<!>.get(0)
+    <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("@Nullable() kotlin.String?;  This will become an error in Kotlin 2.1. See https://youtrack.jetbrains.com/issue/KT-63209.")!>element!!.get(0)<!>.length
+}
+
+fun main3() {
+    val list = A1.warningWarningError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("kotlin.collections.(Mutable)List<(@Nullable() kotlin.collections.MutableList<@Nullable() kotlin.String?>?..@Nullable() kotlin.collections.List<@Nullable() kotlin.String?>?)>?")!>list<!>.get(0)
+    <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("(@Nullable() kotlin.collections.MutableList<@Nullable() kotlin.String?>?..@Nullable() kotlin.collections.List<@Nullable() kotlin.String?>?)")!>element<!>.get(0)
+    <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("@Nullable() kotlin.String?;  This will become an error in Kotlin 2.1. See https://youtrack.jetbrains.com/issue/KT-63209.")!>element!!.get(0)<!>.length
+}
+
+fun main4() {
+    val list = A1.warningErrorWarning()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("kotlin.collections.(Mutable)List<(@Nullable() kotlin.collections.MutableList<@Nullable() kotlin.String?>?..@Nullable() kotlin.collections.List<@Nullable() kotlin.String?>?)>?")!>list<!>.get(0)
+    <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("(@Nullable() kotlin.collections.MutableList<@Nullable() kotlin.String?>?..@Nullable() kotlin.collections.List<@Nullable() kotlin.String?>?);  This will become an error in Kotlin 2.1. See https://youtrack.jetbrains.com/issue/KT-63209.")!>element<!>.get(0)
+    <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("@Nullable() kotlin.String?")!>element!!.get(0)<!>.length
+}
+
+fun main5() {
+    val list = A1.warningPlatformError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("kotlin.collections.(Mutable)List<kotlin.collections.(Mutable)List<@Nullable() kotlin.String?>!>?")!>list<!>.get(0)
+    element.get(0)
+    <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS("@Nullable() kotlin.String?;  This will become an error in Kotlin 2.1. See https://youtrack.jetbrains.com/issue/KT-63209.")!>element!!.get(0)<!>.length
+}

compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningBefore.kt

@@ -0,0 +1,71 @@
+// NULLABILITY_ANNOTATIONS: @io.reactivex.rxjava3.annotations:strict, @org.eclipse.jdt.annotation:warn
+// LANGUAGE: -SupportJavaErrorEnhancementOfArgumentsOfWarningLevelEnhanced
+// SOURCE_RETENTION_ANNOTATIONS
+// MUTE_FOR_PSI_CLASS_FILES_READING
+// ^because annotations don't allow type parameter use.
+// ISSUE: KT-63209
+
+// FILE: A1.java
+import java.util.List;
+
+public class A1 {
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable String> warningError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable List<@io.reactivex.rxjava3.annotations.Nullable String>> warningErrorError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@org.eclipse.jdt.annotation.Nullable List<@io.reactivex.rxjava3.annotations.Nullable String>> warningWarningError() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<@io.reactivex.rxjava3.annotations.Nullable List<@org.eclipse.jdt.annotation.Nullable String>> warningErrorWarning() {
+        return null;
+    }
+
+    @org.eclipse.jdt.annotation.Nullable
+    public static List<List<@io.reactivex.rxjava3.annotations.Nullable String>> warningPlatformError() {
+        return null;
+    }
+}
+
+// FILE: main.kt
+fun main1() {
+    val list = A1.warningError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element.length
+}
+
+fun main2() {
+    val list = A1.warningErrorError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element.get(0)
+    element!!.get(0).length
+}
+
+fun main3() {
+    val list = A1.warningWarningError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element.get(0)
+    element!!.get(0).length
+}
+
+fun main4() {
+    val list = A1.warningErrorWarning()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element.get(0)
+    element!!.get(0).length
+}
+
+fun main5() {
+    val list = A1.warningPlatformError()
+    val element = <!RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>list<!>.get(0)
+    element.get(0)
+    element!!.get(0).length
+}

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

@@ -68,6 +68,18 @@ public class ForeignAnnotationsCompiledJavaTestGenerated extends AbstractForeign
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/eclipse.kt");
         }
 
+        @Test
+        @TestMetadata("errorArgumentOfWarningAfter.kt")
+        public void testErrorArgumentOfWarningAfter() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningAfter.kt");
+        }
+
+        @Test
+        @TestMetadata("errorArgumentOfWarningBefore.kt")
+        public void testErrorArgumentOfWarningBefore() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningBefore.kt");
+        }
+
         @Test
         @TestMetadata("findBugsSimple.kt")
         public void testFindBugsSimple() throws Exception {

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

@@ -68,6 +68,18 @@ public class ForeignAnnotationsCompiledJavaWithPsiClassReadingTestGenerated exte
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/eclipse.kt");
         }
 
+        @Test
+        @TestMetadata("errorArgumentOfWarningAfter.kt")
+        public void testErrorArgumentOfWarningAfter() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningAfter.kt");
+        }
+
+        @Test
+        @TestMetadata("errorArgumentOfWarningBefore.kt")
+        public void testErrorArgumentOfWarningBefore() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningBefore.kt");
+        }
+
         @Test
         @TestMetadata("findBugsSimple.kt")
         public void testFindBugsSimple() throws Exception {

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

@@ -68,6 +68,18 @@ public class ForeignAnnotationsSourceJavaTestGenerated extends AbstractForeignAn
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/eclipse.kt");
         }
 
+        @Test
+        @TestMetadata("errorArgumentOfWarningAfter.kt")
+        public void testErrorArgumentOfWarningAfter() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningAfter.kt");
+        }
+
+        @Test
+        @TestMetadata("errorArgumentOfWarningBefore.kt")
+        public void testErrorArgumentOfWarningBefore() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/errorArgumentOfWarningBefore.kt");
+        }
+
         @Test
         @TestMetadata("findBugsSimple.kt")
         public void testFindBugsSimple() throws Exception {

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -318,6 +318,7 @@ enum class LanguageFeature(
     ProhibitSingleNamedFunctionAsExpression(KOTLIN_2_1, kind = BUG_FIX), // KT-62573
     ForbidLambdaParameterWithMissingDependencyType(KOTLIN_2_1, kind = BUG_FIX), // KT-64266
     JsAllowInvalidCharsIdentifiersEscaping(KOTLIN_2_1, kind = OTHER), // KT-31799
+    SupportJavaErrorEnhancementOfArgumentsOfWarningLevelEnhanced(KOTLIN_2_1, kind = BUG_FIX), // KT-63209
 
     // End of 2.* language features --------------------------------------------------