[FIR] Java super-type arguments are now handled as flexible

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

@@ -27,6 +27,7 @@ import org.jetbrains.kotlin.fir.scopes.FirScope
 import org.jetbrains.kotlin.fir.scopes.impl.*
 import org.jetbrains.kotlin.fir.symbols.CallableId
 import org.jetbrains.kotlin.fir.symbols.impl.*
+import org.jetbrains.kotlin.fir.types.ConeNullability
 import org.jetbrains.kotlin.fir.types.impl.ConeTypeParameterTypeImpl
 import org.jetbrains.kotlin.fir.types.impl.FirResolvedTypeRefImpl
 import org.jetbrains.kotlin.load.java.JavaClassFinder
@@ -95,7 +96,7 @@ class JavaSymbolProvider(
     ) {
         require(this is FirTypeParameterImpl)
         for (upperBound in javaTypeParameter.upperBounds) {
-            bounds += upperBound.toFirResolvedTypeRef(this@JavaSymbolProvider.session, stack, isNullable = true)
+            bounds += upperBound.toFirResolvedTypeRef(this@JavaSymbolProvider.session, stack, nullability = ConeNullability.NULLABLE)
         }
         addDefaultBoundIfNecessary()
     }
@@ -155,7 +156,9 @@ class JavaSymbolProvider(
                     this.typeParameters += foundClass.typeParameters.convertTypeParameters(javaTypeParameterStack)
                     addAnnotationsFrom(this@JavaSymbolProvider.session, javaClass, javaTypeParameterStack)
                     for (supertype in javaClass.supertypes) {
-                        superTypeRefs += supertype.toFirResolvedTypeRef(this@JavaSymbolProvider.session, javaTypeParameterStack)
+                        superTypeRefs += supertype.toFirResolvedTypeRef(
+                            this@JavaSymbolProvider.session, javaTypeParameterStack, typeParametersNullability = ConeNullability.UNKNOWN
+                        )
                     }
                     // TODO: may be we can process fields & methods later.
                     // However, they should be built up to override resolve stage

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

@@ -78,8 +78,8 @@ internal fun FirTypeRef.toNotNullConeKotlinType(
 
 internal fun JavaType?.toNotNullConeKotlinType(
     session: FirSession, javaTypeParameterStack: JavaTypeParameterStack
-): ConeLookupTagBasedType {
+): ConeKotlinType {
-    return toConeKotlinTypeWithNullability(session, javaTypeParameterStack, isNullable = false)
+    return toConeKotlinTypeWithNullability(session, javaTypeParameterStack, ConeNullability.NOT_NULL)
 }
 
 internal fun JavaType.toFirJavaTypeRef(session: FirSession, javaTypeParameterStack: JavaTypeParameterStack): FirJavaTypeRef {
@@ -91,9 +91,12 @@ internal fun JavaType.toFirJavaTypeRef(session: FirSession, javaTypeParameterSta
 }
 
 internal fun JavaClassifierType.toFirResolvedTypeRef(
-    session: FirSession, javaTypeParameterStack: JavaTypeParameterStack, isNullable: Boolean = false
+    session: FirSession,
+    javaTypeParameterStack: JavaTypeParameterStack,
+    nullability: ConeNullability = ConeNullability.NOT_NULL,
+    typeParametersNullability: ConeNullability = ConeNullability.NOT_NULL
 ): FirResolvedTypeRef {
-    val coneType = this.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, isNullable)
+    val coneType = this.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, nullability, typeParametersNullability)
     return FirResolvedTypeRefImpl(
         source = null, type = coneType
     ).apply {
@@ -102,11 +105,14 @@ internal fun JavaClassifierType.toFirResolvedTypeRef(
 }
 
 internal fun JavaType?.toConeKotlinTypeWithNullability(
-    session: FirSession, javaTypeParameterStack: JavaTypeParameterStack, isNullable: Boolean
+    session: FirSession,
-): ConeLookupTagBasedType {
+    javaTypeParameterStack: JavaTypeParameterStack,
+    nullability: ConeNullability,
+    typeParametersNullability: ConeNullability = ConeNullability.NOT_NULL
+): ConeKotlinType {
     return when (this) {
         is JavaClassifierType -> {
-            toConeKotlinTypeWithNullability(session, isNullable, javaTypeParameterStack)
+            toConeKotlinTypeWithNullability(session, nullability, typeParametersNullability, javaTypeParameterStack)
         }
         is JavaPrimitiveType -> {
             val primitiveType = type
@@ -115,38 +121,47 @@ internal fun JavaType?.toConeKotlinTypeWithNullability(
                 else -> javaName.capitalize()
             }
             val classId = StandardClassIds.byName(kotlinPrimitiveName)
-            classId.toConeKotlinType(emptyArray(), isNullable)
+            classId.toConeKotlinType(emptyArray(), nullability.isNullable)
         }
         is JavaArrayType -> {
             val componentType = componentType
             if (componentType !is JavaPrimitiveType) {
                 val classId = StandardClassIds.Array
                 val argumentType = ConeFlexibleType(
-                    componentType.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, isNullable = false),
+                    componentType.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, ConeNullability.NOT_NULL),
-                    componentType.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, isNullable = true)
+                    componentType.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, ConeNullability.NULLABLE)
                 )
-                classId.toConeKotlinType(arrayOf(argumentType), isNullable)
+                classId.toConeKotlinType(arrayOf(argumentType), nullability.isNullable)
             } else {
                 val javaComponentName = componentType.type?.typeName?.asString()?.capitalize() ?: error("Array of voids")
                 val classId = StandardClassIds.byName(javaComponentName + "Array")
-                classId.toConeKotlinType(emptyArray(), isNullable)
+                classId.toConeKotlinType(emptyArray(), nullability.isNullable)
             }
         }
         is JavaWildcardType -> bound?.toNotNullConeKotlinType(session, javaTypeParameterStack) ?: run {
             val classId = StandardClassIds.Any
-            classId.toConeKotlinType(emptyArray(), isNullable)
+            classId.toConeKotlinType(emptyArray(), nullability.isNullable)
         }
         null -> {
             val classId = StandardClassIds.Any
-            classId.toConeKotlinType(emptyArray(), isNullable)
+            classId.toConeKotlinType(emptyArray(), nullability.isNullable)
         }
         else -> error("Strange JavaType: ${this::class.java}")
     }
 }
 
 internal fun JavaClassifierType.toConeKotlinTypeWithNullability(
-    session: FirSession, isNullable: Boolean, javaTypeParameterStack: JavaTypeParameterStack
+    session: FirSession,
-): ConeLookupTagBasedType {
+    nullability: ConeNullability,
+    typeParametersNullability: ConeNullability,
+    javaTypeParameterStack: JavaTypeParameterStack
+): ConeKotlinType {
+    if (nullability == ConeNullability.UNKNOWN) {
+        return ConeFlexibleType(
+            toConeKotlinTypeWithNullability(session, ConeNullability.NOT_NULL, typeParametersNullability, javaTypeParameterStack),
+            toConeKotlinTypeWithNullability(session, ConeNullability.NULLABLE, typeParametersNullability, javaTypeParameterStack)
+        )
+    }
     return when (val classifier = classifier) {
         is JavaClass -> {
             //val classId = classifier.classId!!
@@ -155,17 +170,16 @@ internal fun JavaClassifierType.toConeKotlinTypeWithNullability(
 
             val lookupTag = ConeClassLikeLookupTagImpl(classId)
             lookupTag.constructClassType(
-                typeArguments.mapIndexed { index, argument ->
+                typeArguments.map { argument ->
                     argument.toConeProjection(
-                        session, javaTypeParameterStack, null
+                        session, javaTypeParameterStack, boundTypeParameter = null, nullability = typeParametersNullability
-                        //symbol.fir.typeParameters.getOrNull(index)
                     )
-                }.toTypedArray(), isNullable
+                }.toTypedArray(), nullability.isNullable
             )
         }
         is JavaTypeParameter -> {
             val symbol = javaTypeParameterStack[classifier]
-            ConeTypeParameterTypeImpl(symbol.toLookupTag(), isNullable)
+            ConeTypeParameterTypeImpl(symbol.toLookupTag(), nullability.isNullable)
         }
         else -> ConeClassErrorType(reason = "Unexpected classifier: $classifier")
     }
@@ -208,7 +222,10 @@ internal fun JavaValueParameter.toFirValueParameter(
 }
 
 internal fun JavaType?.toConeProjection(
-    session: FirSession, javaTypeParameterStack: JavaTypeParameterStack, boundTypeParameter: FirTypeParameter?
+    session: FirSession,
+    javaTypeParameterStack: JavaTypeParameterStack,
+    boundTypeParameter: FirTypeParameter?,
+    nullability: ConeNullability = ConeNullability.NOT_NULL
 ): ConeKotlinTypeProjection {
     return when (this) {
         null -> ConeStarProjection
@@ -219,7 +236,7 @@ internal fun JavaType?.toConeProjection(
             if (bound == null || parameterVariance != INVARIANT && parameterVariance != argumentVariance) {
                 ConeStarProjection
             } else {
-                val boundType = bound.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, isNullable = false)
+                val boundType = bound.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, nullability)
                 if (argumentVariance == OUT_VARIANCE) {
                     ConeKotlinTypeProjectionOut(boundType)
                 } else {
@@ -227,7 +244,7 @@ internal fun JavaType?.toConeProjection(
                 }
             }
         }
-        is JavaClassifierType -> toConeKotlinTypeWithNullability(session, javaTypeParameterStack, isNullable = false)
+        is JavaClassifierType -> toConeKotlinTypeWithNullability(session, javaTypeParameterStack, nullability)
         else -> ConeClassErrorType("Unexpected type argument: $this")
     }
 }
@@ -260,7 +277,9 @@ private fun JavaAnnotationArgument.toFirExpression(
                     null
                 }
                 this.calleeReference = calleeReference
-                    ?: FirErrorNamedReferenceImpl(null, FirSimpleDiagnostic("Strange Java enum value: $classId.$entryName", DiagnosticKind.Java))
+                    ?: FirErrorNamedReferenceImpl(
+                        null, FirSimpleDiagnostic("Strange Java enum value: $classId.$entryName", DiagnosticKind.Java)
+                    )
             }
         }
         is JavaClassObjectAnnotationArgument -> FirGetClassCallImpl(null).apply {
@@ -270,7 +289,9 @@ private fun JavaAnnotationArgument.toFirExpression(
             )
         }
         is JavaAnnotationAsAnnotationArgument -> getAnnotation().toFirAnnotationCall(session, javaTypeParameterStack)
-        else -> FirErrorExpressionImpl(null, FirSimpleDiagnostic("Unknown JavaAnnotationArgument: ${this::class.java}", DiagnosticKind.Java))
+        else -> FirErrorExpressionImpl(
+            null, FirSimpleDiagnostic("Unknown JavaAnnotationArgument: ${this::class.java}", DiagnosticKind.Java)
+        )
     }
 }
 
@@ -304,7 +325,9 @@ internal fun Any?.createConstant(session: FirSession): FirExpression {
         is BooleanArray -> toList().createArrayOfCall(session, FirConstKind.Boolean)
         null -> FirConstExpressionImpl(null, FirConstKind.Null, null)
 
-        else -> FirErrorExpressionImpl(null, FirSimpleDiagnostic("Unknown value in JavaLiteralAnnotationArgument: $this", DiagnosticKind.Java))
+        else -> FirErrorExpressionImpl(
+            null, FirSimpleDiagnostic("Unknown value in JavaLiteralAnnotationArgument: $this", DiagnosticKind.Java)
+        )
     }
 }
 

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

@@ -152,8 +152,8 @@ internal class EnhancementSignatureParts(
             is FirJavaTypeRef -> {
                 Pair(
                     // TODO: optimize
-                    type.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, isNullable = false),
+                    type.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, nullability = ConeNullability.NOT_NULL),
-                    type.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, isNullable = true)
+                    type.toConeKotlinTypeWithNullability(session, javaTypeParameterStack, nullability = ConeNullability.NULLABLE)
                 )
             }
             else -> return JavaTypeQualifiers.NONE

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

@@ -19,7 +19,6 @@ import org.jetbrains.kotlin.fir.java.declarations.FirJavaField
 import org.jetbrains.kotlin.fir.java.toConeProjection
 import org.jetbrains.kotlin.fir.java.toNotNullConeKotlinType
 import org.jetbrains.kotlin.fir.references.impl.FirResolvedNamedReferenceImpl
-import org.jetbrains.kotlin.fir.references.impl.FirSimpleNamedReference
 import org.jetbrains.kotlin.fir.resolve.*
 import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.firUnsafe
 import org.jetbrains.kotlin.fir.symbols.ConeClassLikeLookupTag
@@ -124,12 +123,12 @@ private fun JavaType?.subtreeSize(): Int {
 
 private fun coneFlexibleOrSimpleType(
     session: FirSession,
-    lowerBound: ConeLookupTagBasedType,
+    lowerBound: ConeKotlinType,
-    upperBound: ConeLookupTagBasedType,
+    upperBound: ConeKotlinType,
     isNotNullTypeParameter: Boolean
 ): ConeKotlinType {
     if (AbstractStrictEqualityTypeChecker.strictEqualTypes(session.typeContext, lowerBound, upperBound)) {
-        val lookupTag = lowerBound.lookupTag
+        val lookupTag = (lowerBound as? ConeLookupTagBasedType)?.lookupTag
         if (isNotNullTypeParameter && lookupTag is ConeTypeParameterLookupTag && !lowerBound.isMarkedNullable) {
             // TODO: we need enhancement for type parameter bounds for this code to work properly
             // At this moment, this condition is always true
@@ -164,8 +163,6 @@ private fun ClassId.mutableToReadOnly(): ClassId? {
     }
 }
 
-
-
 // Definition:
 // ErasedUpperBound(T : G<t>) = G<*> // UpperBound(T) is a type G<t> with arguments
 // ErasedUpperBound(T : A) = A // UpperBound(T) is a type A without arguments
@@ -181,8 +178,7 @@ private fun FirTypeParameter.getErasedUpperBound(
 
     val firstUpperBound = this.bounds.first().coneTypeUnsafe<ConeKotlinType>()
 
-    val firstUpperBoundClassifier = firstUpperBound
+    if (firstUpperBound is ConeClassLikeType) {
-    if (firstUpperBoundClassifier is ConeClassLikeType) {
         return firstUpperBound.withArguments(firstUpperBound.typeArguments.map { ConeStarProjection }.toTypedArray())
     }
 
@@ -225,7 +221,8 @@ fun computeProjection(
         // in T -> Comparable<Nothing>
             session.builtinTypes.nothingType.type
         else if (erasedUpperBound is ConeClassLikeType &&
-            erasedUpperBound.lookupTag.toSymbol(session)!!.firUnsafe<FirRegularClass>().typeParameters.isNotEmpty())
+            erasedUpperBound.lookupTag.toSymbol(session)!!.firUnsafe<FirRegularClass>().typeParameters.isNotEmpty()
+        )
         // T : Enum<E> -> out Enum<*>
             ConeKotlinTypeProjectionOut(erasedUpperBound)
         else
@@ -234,8 +231,6 @@ fun computeProjection(
     }
 }
 
-
-
 private fun JavaClassifierType.enhanceInflexibleType(
     session: FirSession,
     javaTypeParameterStack: JavaTypeParameterStack,
@@ -244,9 +239,8 @@ private fun JavaClassifierType.enhanceInflexibleType(
     position: TypeComponentPosition,
     qualifiers: IndexedJavaTypeQualifiers,
     index: Int
-): ConeLookupTagBasedType {
+): ConeKotlinType {
-    val classifier = classifier
+    val originalTag = when (val classifier = classifier) {
-    val originalTag = when (classifier) {
         is JavaClass -> {
             val classId = classifier.classId!!
             var mappedId = JavaToKotlinClassMap.mapJavaToKotlin(classId.asSingleFqName())

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

@@ -217,10 +217,17 @@ fun coneFlexibleOrSimpleType(
     if (upperBound is ConeFlexibleType) {
         return coneFlexibleOrSimpleType(typeContext, lowerBound, upperBound.upperBound)
     }
-    if (typeContext != null && AbstractStrictEqualityTypeChecker.strictEqualTypes(typeContext, lowerBound, upperBound)) {
+    return when {
-        return lowerBound
+        typeContext != null && AbstractStrictEqualityTypeChecker.strictEqualTypes(typeContext, lowerBound, upperBound) -> {
+            lowerBound
+        }
+        typeContext == null && lowerBound == upperBound -> {
+            lowerBound
+        }
+        else -> {
+            ConeFlexibleType(lowerBound, upperBound)
+        }
     }
-    return ConeFlexibleType(lowerBound, upperBound)
 }
 
 fun <T : ConeKotlinType> T.withNullability(nullability: ConeNullability, typeContext: ConeInferenceContext? = null): T {

compiler/fir/resolve/testData/enhancement/mapping/AbstractMap.fir.txt

@@ -1,4 +1,4 @@
-public abstract class AbstractMap : R|kotlin/Any|, R|kotlin/collections/MutableMap<kotlin/String, kotlin/String>| {
+public abstract class AbstractMap : R|kotlin/Any|, R|kotlin/collections/MutableMap<ft<kotlin/String, kotlin/String?>!, ft<kotlin/String, kotlin/String?>!>| {
     public constructor(): R|AbstractMap|
 
 }

compiler/fir/resolve/testData/enhancement/signatureAnnotations/DefaultEnum.fir.txt

@@ -10,7 +10,7 @@ public/*package*/ open class A : R|kotlin/Any| {
     public/*package*/ constructor(): R|A|
 
 }
-public final enum class Mixed : R|kotlin/Enum<Mixed>| {
+public final enum class Mixed : R|kotlin/Enum<ft<Mixed, Mixed?>!>| {
     public final static field NOT_ENTRY_EITHER: R|ft<Mixed, Mixed?>!|
 
     public final static fun values(): R|kotlin/Array<Mixed>| {
@@ -20,7 +20,7 @@ public final enum class Mixed : R|kotlin/Enum<Mixed>| {
     }
 
 }
-public final enum class Signs : R|kotlin/Enum<Signs>| {
+public final enum class Signs : R|kotlin/Enum<ft<Signs, Signs?>!>| {
     public final static field HELLO: R|ft<Signs, Signs?>!|
 
     public final static field WORLD: R|ft<Signs, Signs?>!|

compiler/fir/resolve/testData/resolve/stdlib/hashSet.txt

@@ -1,10 +1,10 @@
 FILE: hashSet.kt
-    public final val a: R|kotlin/collections/MutableSet<kotlin/String>?| = R|java/util/HashSet.HashSet|<R|kotlin/String|>()
+    public final val a: R|kotlin/collections/MutableSet<kotlin/String>?| = R|java/util/HashSet.HashSet|<R|ft<kotlin/String, kotlin/String?>!|>()
         public get(): R|kotlin/collections/MutableSet<kotlin/String>?|
     public final var b: R|kotlin/collections/MutableSet<kotlin/String>?| = Null(null)
         public get(): R|kotlin/collections/MutableSet<kotlin/String>?|
         public set(_: R|kotlin/collections/MutableSet<kotlin/String>?|): R|kotlin/Unit| {
-            F|/b| = R|java/util/HashSet.HashSet|<R|kotlin/String|>()
+            F|/b| = R|java/util/HashSet.HashSet|<R|ft<kotlin/String, kotlin/String?>!|>()
         }
     public final var <T> R|kotlin/collections/MutableSet<T>|.d: R|T?|
         public get(): R|T?| {
@@ -17,6 +17,6 @@ FILE: hashSet.kt
     }
     public final fun foo(): R|kotlin/Unit| {
         lvar c: R|kotlin/collections/MutableSet<kotlin/String>?| = Null(null)
-        R|<local>/c| = R|java/util/HashSet.HashSet|<R|kotlin/String|>()
+        R|<local>/c| = R|java/util/HashSet.HashSet|<R|ft<kotlin/String, kotlin/String?>!|>()
         R|<local>/c|!!.R|/d| = R|/produce|<R|T?|>()
     }

compiler/fir/resolve/testData/resolve/stdlib/j+k/KJKInheritanceGeneric.txt

@@ -16,7 +16,7 @@ FILE: K2.kt
         }
 
         public final fun bar(): R|kotlin/Unit| {
-            this@R|/K2|.R|FakeOverride</KFirst.foo: R|kotlin/Int|>|(Int(1))
+            this@R|/K2|.R|FakeOverride</KFirst.foo: R|ft<kotlin/Int, kotlin/Int?>!|>|(Int(1))
             this@R|/K2|.R|/J1.baz|()
         }
 

compiler/fir/resolve/testData/resolve/stdlib/j+k/MapEntry.kt

@@ -17,7 +17,7 @@ class MyMapEntry : Test.MapEntryImpl()
 
 fun test() {
     val b = MyMapEntry()
-    b.key
+    val key = b.key
-    b.value
+    val value = b.value
     b.setValue(null)
 }

compiler/fir/resolve/testData/resolve/stdlib/j+k/MapEntry.txt

@@ -7,7 +7,7 @@ FILE: main.kt
     }
     public final fun test(): R|kotlin/Unit| {
         lval b: R|MyMapEntry| = R|/MyMapEntry.MyMapEntry|()
-        R|<local>/b|.R|/Test.MapEntryImpl.key|
+        lval key: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/b|.R|/Test.MapEntryImpl.key|
-        R|<local>/b|.R|/Test.MapEntryImpl.value|
+        lval value: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/b|.R|/Test.MapEntryImpl.value|
         R|<local>/b|.R|/Test.MapEntryImpl.setValue|(Null(null))
     }

compiler/fir/resolve/testData/resolve/stdlib/j+k/MyIterable.txt

@@ -1,8 +1,8 @@
 FILE: test.kt
     public abstract interface UseIterable : R|MyIterable<kotlin/String>| {
         public open fun test(): R|kotlin/Unit| {
-            lval it: R|kotlin/collections/MutableIterator<kotlin/String>| = this@R|/UseIterable|.R|FakeOverride<kotlin/collections/MutableIterable.iterator: R|kotlin/collections/MutableIterator<kotlin/String>|>|()
+            lval it: R|kotlin/collections/MutableIterator<ft<kotlin/String, kotlin/String?>!>| = this@R|/UseIterable|.R|FakeOverride<kotlin/collections/MutableIterable.iterator: R|kotlin/collections/MutableIterator<ft<kotlin/String, kotlin/String?>!>|>|()
-            lval split: R|java/util/Spliterator<kotlin/String>| = this@R|/UseIterable|.R|FakeOverride<java/lang/Iterable.spliterator: R|java/util/Spliterator<kotlin/String>|>|()
+            lval split: R|java/util/Spliterator<ft<kotlin/String, kotlin/String?>!>| = this@R|/UseIterable|.R|FakeOverride<java/lang/Iterable.spliterator: R|java/util/Spliterator<ft<kotlin/String, kotlin/String?>!>|>|()
         }
 
     }

compiler/fir/resolve/testData/resolve/stdlib/j+k/MyMap.txt

@@ -1,20 +1,20 @@
 FILE: test.kt
     public final fun test(map: R|MyMap|): R|kotlin/Unit| {
-        lval result: R|kotlin/String| = R|<local>/map|.R|kotlin/collections/getOrPut|<R|kotlin/String|, R|kotlin/String|>(String(key), <L> = getOrPut@fun <anonymous>(): R|kotlin/String| <kind=UNKNOWN>  {
+        lval result: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/map|.R|kotlin/collections/getOrPut|<R|ft<kotlin/String, kotlin/String?>!|, R|ft<kotlin/String, kotlin/String?>!|>(String(key), <L> = getOrPut@fun <anonymous>(): R|kotlin/String| <kind=UNKNOWN>  {
             String(value)
         }
         )
-        lval otherResult: R|kotlin/String| = R|<local>/map|.R|FakeOverride<kotlin/collections/Map.getOrDefault: R|kotlin/String|>|(String(key), String(value))
+        lval otherResult: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/map|.R|FakeOverride<kotlin/collections/Map.getOrDefault: R|ft<kotlin/String, kotlin/String?>!|>|(String(key), String(value))
         lval anotherResult: <ERROR TYPE REF: Unresolved name: replace> = R|<local>/map|.<Unresolved name: replace>#(String(key), String(value))
-        R|<local>/map|.R|FakeOverride<java/util/Map.forEach: R|kotlin/Unit|>|(<L> = forEach@fun <anonymous>(key: R|kotlin/String|, value: R|kotlin/String|): R|kotlin/Unit| {
+        R|<local>/map|.R|FakeOverride<java/util/Map.forEach: R|kotlin/Unit|>|(<L> = forEach@fun <anonymous>(key: R|ft<kotlin/String, kotlin/String?>!|, value: R|ft<kotlin/String, kotlin/String?>!|): R|kotlin/Unit| {
             R|kotlin/io/println|(<strcat>(R|<local>/key|.R|kotlin/Any.toString|(), String(: ), R|<local>/value|.R|kotlin/Any.toString|()))
             R|<local>/key|.R|kotlin/String.length|
             R|<local>/value|.R|kotlin/String.length|
         }
         )
-        R|<local>/map|.R|kotlin/collections/forEach|<R|kotlin/String|, R|kotlin/String|>(<L> = forEach@fun <anonymous>(<destruct>: R|kotlin/collections/Map.Entry<kotlin/String, kotlin/String>|): R|kotlin/Unit| <kind=UNKNOWN>  {
+        R|<local>/map|.R|kotlin/collections/forEach|<R|ft<kotlin/String, kotlin/String?>!|, R|ft<kotlin/String, kotlin/String?>!|>(<L> = forEach@fun <anonymous>(<destruct>: R|kotlin/collections/Map.Entry<ft<kotlin/String, kotlin/String?>!, ft<kotlin/String, kotlin/String?>!>|): R|kotlin/Unit| <kind=UNKNOWN>  {
-            lval key: R|kotlin/String| = R|<local>/<destruct>|.R|kotlin/collections/component1|<R|kotlin/String|, R|kotlin/String|>()
+            lval key: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/<destruct>|.R|kotlin/collections/component1|<R|ft<kotlin/String, kotlin/String?>!|, R|ft<kotlin/String, kotlin/String?>!|>()
-            lval value: R|kotlin/String| = R|<local>/<destruct>|.R|kotlin/collections/component2|<R|kotlin/String|, R|kotlin/String|>()
+            lval value: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/<destruct>|.R|kotlin/collections/component2|<R|ft<kotlin/String, kotlin/String?>!|, R|ft<kotlin/String, kotlin/String?>!|>()
             R|kotlin/io/println|(<strcat>(R|<local>/key|.R|kotlin/Any.toString|(), String(: ), R|<local>/value|.R|kotlin/Any.toString|()))
             R|<local>/key|.R|kotlin/String.length|
             R|<local>/value|.R|kotlin/String.length|

compiler/fir/resolve/testData/resolve/stdlib/removeOnAbstractMap.kt

@@ -1,3 +1,4 @@
 fun test(map: java.util.AbstractMap<String, Int>) {
-    map.<!INAPPLICABLE_CANDIDATE!>remove<!>("", null)
+    map.remove("", null)
+    map.remove(null)
 }

compiler/fir/resolve/testData/resolve/stdlib/removeOnAbstractMap.txt

@@ -1,4 +1,5 @@
 FILE: removeOnAbstractMap.kt
     public final fun test(map: R|java/util/AbstractMap<kotlin/String, kotlin/Int>|): R|kotlin/Unit| {
-        R|<local>/map|.<Inapplicable(INAPPLICABLE): [kotlin/collections/MutableMap.remove]>#(String(), Null(null))
+        R|<local>/map|.R|FakeOverride<kotlin/collections/MutableMap.remove: R|kotlin/Boolean|>|(String(), Null(null))
+        R|<local>/map|.R|FakeOverride<kotlin/collections/MutableMap.remove: R|kotlin/Int?|>|(Null(null))
     }

compiler/fir/resolve/testData/resolve/stdlib/typeAliasWithForEach.txt

@@ -11,7 +11,7 @@ FILE: typeAliasWithForEach.kt
     public final fun R|Arguments|.deepCopy(): R|Arguments| {
         lval result: R|java/util/HashMap<kotlin/String, ArgsInfo>| = R|java/util/HashMap.HashMap|<R|kotlin/String|, R|ArgsInfo|>()
         this@R|/deepCopy|.R|FakeOverride<java/util/Map.forEach: R|kotlin/Unit|>|(<L> = forEach@fun <anonymous>(key: R|kotlin/String|, value: R|ArgsInfo|): R|kotlin/Unit| {
-            R|<local>/result|.R|kotlin/collections/set|<R|kotlin/String|, R|ArgsInfo|>(R|<local>/key|, R|/ArgsInfoImpl.ArgsInfoImpl|(R|<local>/value|))
+            R|<local>/result|.R|kotlin/collections/set|<R|ft<kotlin/String, kotlin/String?>!|, R|ft<ArgsInfo, ArgsInfo?>!|>(R|<local>/key|, R|/ArgsInfoImpl.ArgsInfoImpl|(R|<local>/value|))
         }
         )
         ^deepCopy R|<local>/result|

compiler/testData/diagnostics/tests/platformTypes/methodCall/multipleExactBoundsNullable.fir.kt

@@ -28,11 +28,11 @@ interface WithFoo {
 
 fun <M2: WithFoo> foo(delegateResolver: ResolverForProject<M2?>): ResolverForProject<M2?> {
     val descriptorByModule = MyMap<M2, String>()
-    val result = <!INAPPLICABLE_CANDIDATE!>ResolverForProjectImpl<!>(descriptorByModule, delegateResolver)
+    val result = ResolverForProjectImpl(descriptorByModule, delegateResolver)
-    result.<!UNRESOLVED_REFERENCE!>exposeM<!>.<!UNRESOLVED_REFERENCE!>foo<!>() // M is not M2?
+    result.exposeM.foo() // M is not M2?
-    result.<!UNRESOLVED_REFERENCE!>exposeM<!>?.<!UNRESOLVED_REFERENCE!>foo<!>() // no warning, M is not M2, hense M is M2!
+    result.exposeM?.foo() // no warning, M is not M2, hense M is M2!
 
-    return <!INAPPLICABLE_CANDIDATE!>ResolverForProjectImpl<!>(descriptorByModule, delegateResolver) // another bound check
+    return ResolverForProjectImpl(descriptorByModule, delegateResolver) // another bound check
 }
 
 // MyMap<M2, String> :< Map<M, String> => M = M2!

compiler/testData/diagnostics/tests/subtyping/javaAndKotlinSuperType.fir.kt

@@ -22,10 +22,10 @@ fun test(b: B, c: C, d: D, e: E) {
     eatAString(d)
     eatAString(e)
 
-    <!INAPPLICABLE_CANDIDATE!>eatAStringN<!>(b)
+    eatAStringN(b)
-    <!INAPPLICABLE_CANDIDATE!>eatAStringN<!>(c)
+    eatAStringN(c)
-    <!INAPPLICABLE_CANDIDATE!>eatAStringN<!>(d)
+    eatAStringN(d)
-    <!INAPPLICABLE_CANDIDATE!>eatAStringN<!>(e)
+    eatAStringN(e)
 }
 
 // FILE: 3.kt

compiler/testData/ir/irText/stubs/builtinMap.fir.txt

@@ -26,7 +26,7 @@ FILE fqName:<root> fileName:/builtinMap.kt
                 FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> ($receiver:java.util.LinkedHashMap<K1 of <root>.plus, V1 of <root>.plus>) returnType:kotlin.Unit
                   $receiver: VALUE_PARAMETER name:<this> type:java.util.LinkedHashMap<K1 of <root>.plus, V1 of <root>.plus>
                   BLOCK_BODY
-                    CALL 'public open fun put (p0: K1 of <root>.plus, p1: V1 of <root>.plus): V1 of <root>.plus? [operator] declared in java.util.HashMap' type=V1 of <root>.plus? origin=null
+                    CALL 'public open fun put (p0: K1 of <root>.plus?, p1: V1 of <root>.plus?): V1 of <root>.plus? [operator] declared in java.util.HashMap' type=V1 of <root>.plus? origin=null
                       $this: GET_VAR '<this>: java.util.LinkedHashMap<K1 of <root>.plus, V1 of <root>.plus> declared in special.<anonymous>' type=java.util.LinkedHashMap<K1 of <root>.plus, V1 of <root>.plus> origin=null
                       p0: CALL 'public final fun <get-first> (): K1 of <root>.plus declared in kotlin.Pair' type=K1 of <root>.plus origin=null
                         $this: GET_VAR 'pair: kotlin.Pair<K1 of <root>.plus, V1 of <root>.plus> declared in <root>.plus' type=kotlin.Pair<K1 of <root>.plus, V1 of <root>.plus> origin=null

compiler/testData/loadJava/compiledJava/ClassWithTypePExtendsIterableP.fir.txt

@@ -1,4 +1,4 @@
-public abstract class ClassWithTypePExtendsIterableP<P> : R|kotlin/Any|, R|kotlin/collections/MutableIterable<P>| {
+public abstract class ClassWithTypePExtendsIterableP<P> : R|kotlin/Any|, R|kotlin/collections/MutableIterable<ft<P, P?>!>| {
     public constructor<P>(): R|test/ClassWithTypePExtendsIterableP<P>|
 
 }

compiler/testData/loadJava/compiledJava/annotations/AnnotatedEnumEntry.fir.txt

@@ -1,4 +1,4 @@
-public final enum class AnnotatedEnumEntry : R|kotlin/Enum<test/AnnotatedEnumEntry>| {
+public final enum class AnnotatedEnumEntry : R|kotlin/Enum<ft<test/AnnotatedEnumEntry, test/AnnotatedEnumEntry?>!>| {
     @R|test/AnnotatedEnumEntry.Anno|(String(a)) public final static field E1: R|ft<test/AnnotatedEnumEntry, test/AnnotatedEnumEntry?>!|
 
     @R|test/AnnotatedEnumEntry.Anno|(String(b)) @R|test/AnnotatedEnumEntry.Anno2|() public final static field E2: R|ft<test/AnnotatedEnumEntry, test/AnnotatedEnumEntry?>!|

compiler/testData/loadJava/compiledJava/annotations/EnumConstructorParameter.fir.txt

@@ -1,4 +1,4 @@
-public final enum class EnumConstructorParameter : R|kotlin/Enum<test/EnumConstructorParameter>| {
+public final enum class EnumConstructorParameter : R|kotlin/Enum<ft<test/EnumConstructorParameter, test/EnumConstructorParameter?>!>| {
     public final static field INSTANCE: R|ft<test/EnumConstructorParameter, test/EnumConstructorParameter?>!|
 
     private constructor(@R|test/EnumConstructorParameter.Anno|(String(string)) s: R|ft<kotlin/String, kotlin/String?>!|): R|test/EnumConstructorParameter|

compiler/testData/loadJava/compiledJava/enum/EnumMembers.fir.txt

@@ -1,4 +1,4 @@
-public final enum class EnumMembers : R|kotlin/Enum<test/EnumMembers>| {
+public final enum class EnumMembers : R|kotlin/Enum<ft<test/EnumMembers, test/EnumMembers?>!>| {
     public final static field FIRST: R|ft<test/EnumMembers, test/EnumMembers?>!|
 
     public final static field SECOND: R|ft<test/EnumMembers, test/EnumMembers?>!|

compiler/testData/loadJava/compiledJava/enum/EnumWithSpecializedEntry.fir.txt

@@ -1,4 +1,4 @@
-public open enum class EnumWithSpecializedEntry : R|kotlin/Enum<test/EnumWithSpecializedEntry>| {
+public open enum class EnumWithSpecializedEntry : R|kotlin/Enum<ft<test/EnumWithSpecializedEntry, test/EnumWithSpecializedEntry?>!>| {
     public final static field E1: R|ft<test/EnumWithSpecializedEntry, test/EnumWithSpecializedEntry?>!|
 
     public final static field E2: R|ft<test/EnumWithSpecializedEntry, test/EnumWithSpecializedEntry?>!|

compiler/testData/loadJava/compiledJava/enum/JavaEnum.fir.txt

@@ -1,4 +1,4 @@
-public final enum class JavaEnum : R|kotlin/Enum<test/JavaEnum>| {
+public final enum class JavaEnum : R|kotlin/Enum<ft<test/JavaEnum, test/JavaEnum?>!>| {
     public final static field ENTRY: R|ft<test/JavaEnum, test/JavaEnum?>!|
 
     public final static field ANOTHER: R|ft<test/JavaEnum, test/JavaEnum?>!|

compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/SubclassOfCollection.fir.txt

@@ -1,4 +1,4 @@
-public abstract interface SubclassOfCollection<E> : R|kotlin/collections/MutableCollection<E>| {
+public abstract interface SubclassOfCollection<E> : R|kotlin/collections/MutableCollection<ft<E, E?>!>| {
     public abstract operator fun iterator(): R|kotlin/collections/MutableIterator<ft<E, E?>!>|
 
 }

compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/SubclassOfMapEntry.fir.txt

@@ -1,4 +1,4 @@
-public abstract interface SubclassOfMapEntry<K, V> : R|kotlin/collections/MutableMap.MutableEntry<K, V>| {
+public abstract interface SubclassOfMapEntry<K, V> : R|kotlin/collections/MutableMap.MutableEntry<ft<K, K?>!, ft<V, V?>!>| {
-    public abstract operator fun setValue(value: R|V|): R|V|
+    public abstract operator fun setValue(value: R|ft<V, V?>!|): R|ft<V, V?>!|
 
 }

compiler/testData/loadJava/compiledJava/modality/ModalityOfFakeOverrides.fir.txt

@@ -1,4 +1,4 @@
-public open class ModalityOfFakeOverrides : R|java/util/AbstractList<kotlin/String>| {
+public open class ModalityOfFakeOverrides : R|java/util/AbstractList<ft<kotlin/String, kotlin/String?>!>| {
     @R|java/lang/Override|() @R|org/jetbrains/annotations/NotNull|() public open operator fun get(index: R|kotlin/Int|): R|kotlin/String|
 
     @R|java/lang/Override|() public open operator fun size(): R|kotlin/Int|

compiler/testData/loadJava/compiledJava/sam/SubstitutedSamInterface.fir.txt

@@ -1,2 +1,2 @@
-public abstract interface SubstitutedSamInterface : R|java/util/Comparator<kotlin/String>| {
+public abstract interface SubstitutedSamInterface : R|java/util/Comparator<ft<kotlin/String, kotlin/String?>!>| {
 }

compiler/testData/loadJava/compiledJava/sam/SubstitutedSamInterfaceSubclassOfBuiltin.fir.txt

@@ -1,2 +1,2 @@
-public abstract interface SubstitutedSamInterfaceSubclassOfBuiltin : R|kotlin/Comparable<test/SubstitutedSamInterfaceSubclassOfBuiltin>| {
+public abstract interface SubstitutedSamInterfaceSubclassOfBuiltin : R|kotlin/Comparable<ft<test/SubstitutedSamInterfaceSubclassOfBuiltin, test/SubstitutedSamInterfaceSubclassOfBuiltin?>!>| {
 }

compiler/testData/loadJava/compiledJava/static/Enum.fir.txt

@@ -1,4 +1,4 @@
-public final enum class Enum : R|kotlin/Enum<test/Enum>| {
+public final enum class Enum : R|kotlin/Enum<ft<test/Enum, test/Enum?>!>| {
     public final static field A: R|ft<test/Enum, test/Enum?>!|
 
     public final static field B: R|ft<test/Enum, test/Enum?>!|

compiler/testData/loadJava/compiledJava/static/StaticMembersInEnum.fir.txt

@@ -1,4 +1,4 @@
-public final enum class StaticMembersInEnum : R|kotlin/Enum<test/StaticMembersInEnum>| {
+public final enum class StaticMembersInEnum : R|kotlin/Enum<ft<test/StaticMembersInEnum, test/StaticMembersInEnum?>!>| {
     public final static field ENTRY: R|ft<test/StaticMembersInEnum, test/StaticMembersInEnum?>!|
 
     public open static field STATIC_FIELD: R|kotlin/Int|