K2: expand type before isSomeType checks properly

Related to KT-60229

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/references/FirReferenceResolveHelper.kt

@@ -33,6 +33,7 @@ import org.jetbrains.kotlin.fir.psi
 import org.jetbrains.kotlin.fir.references.*
 import org.jetbrains.kotlin.fir.resolve.ScopeSession
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeUnmatchedTypeArgumentsError
+import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.resolve.providers.toSymbol
 import org.jetbrains.kotlin.fir.resolve.scope
 import org.jetbrains.kotlin.fir.resolve.toSymbol
@@ -261,7 +262,7 @@ internal object FirReferenceResolveHelper {
         return buildList {
             scope.processFunctionsByName(OperatorNameConventions.EQUALS) { functionSymbol ->
                 val parameterSymbol = functionSymbol.valueParameterSymbols.singleOrNull()
-                if (parameterSymbol != null && parameterSymbol.fir.returnTypeRef.isNullableAny) {
+                if (parameterSymbol != null && parameterSymbol.fir.returnTypeRef.coneType.fullyExpandedType(session).isNullableAny) {
                     add(functionSymbol.buildSymbol(symbolBuilder))
                 }
             }

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/symbols/KtFirTypeParameterSymbolBase.kt

@@ -19,6 +19,7 @@ import org.jetbrains.kotlin.analysis.api.types.KtType
 import org.jetbrains.kotlin.fir.symbols.impl.FirTypeParameterSymbol
 import org.jetbrains.kotlin.fir.types.isNullableAny
 import org.jetbrains.kotlin.fir.analysis.checkers.typeParameterSymbols
+import org.jetbrains.kotlin.fir.types.UnexpandedTypeCheck
 
 /**
  * [KtFirTypeParameterSymbolBase] provides shared implementations for [KtFirTypeParameterSymbol] and [KtFirPsiJavaTypeParameterSymbol].
@@ -29,6 +30,7 @@ internal sealed class KtFirTypeParameterSymbolBase : KtTypeParameterSymbol(), Kt
             KtFirAnnotationListForDeclaration.create(firSymbol, analysisSession.useSiteSession, token)
         }
 
+    @OptIn(UnexpandedTypeCheck::class)
     override val upperBounds: List<KtType> by cached {
         firSymbol.resolvedBounds.mapNotNull { type ->
             if (type.isNullableAny) return@mapNotNull null

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/FirKotlinToJvmBytecodeCompiler.kt

@@ -40,7 +40,6 @@ import org.jetbrains.kotlin.fir.types.isArrayType
 import org.jetbrains.kotlin.fir.types.isString
 import org.jetbrains.kotlin.fir.visitors.FirVisitorVoid
 import org.jetbrains.kotlin.ir.backend.jvm.serialization.JvmIrMangler
-import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.load.kotlin.incremental.components.IncrementalCompilationComponents
 import org.jetbrains.kotlin.modules.Module
 import org.jetbrains.kotlin.modules.TargetId

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

@@ -165,7 +165,7 @@ object FirRepeatableAnnotationChecker : FirBasicDeclarationChecker() {
         val valueParameterSymbols = containerCtor.valueParameterSymbols
         val parameterName = StandardClassIds.Annotations.ParameterNames.value
         val value = valueParameterSymbols.find { it.name == parameterName }
-        if (value == null || !value.resolvedReturnTypeRef.isArrayType ||
+        if (value == null || !value.resolvedReturnTypeRef.coneType.fullyExpandedType(context.session).isArrayType ||
             value.resolvedReturnTypeRef.type.typeArguments.single().type != annotationClass.defaultType()
         ) {
             reporter.reportOn(

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

@@ -13,10 +13,10 @@ import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.declarations.FirRegularClass
 import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
+import org.jetbrains.kotlin.fir.declarations.isEquals
 import org.jetbrains.kotlin.fir.declarations.utils.hasBody
 import org.jetbrains.kotlin.fir.declarations.utils.isInterface
 import org.jetbrains.kotlin.fir.declarations.utils.isOverride
-import org.jetbrains.kotlin.fir.symbols.impl.isEquals
 import org.jetbrains.kotlin.name.CallableId
 import org.jetbrains.kotlin.util.OperatorNameConventions.TO_STRING
 
@@ -43,7 +43,7 @@ object FirMethodOfAnyImplementedInInterfaceChecker : FirRegularClassChecker(), F
                 (function.name == HASHCODE_NAME || function.name == TO_STRING)
             ) {
                 methodOfAny = true
-            } else if (function.isEquals()) {
+            } else if (function.isEquals(context.session)) {
                 methodOfAny = true
             }
 

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

@@ -24,7 +24,6 @@ import org.jetbrains.kotlin.fir.resolve.defaultType
 import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.resolve.lookupSuperTypes
 import org.jetbrains.kotlin.fir.symbols.impl.FirValueParameterSymbol
-import org.jetbrains.kotlin.fir.symbols.impl.isEquals
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.impl.FirImplicitAnyTypeRef
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -192,7 +191,7 @@ object FirValueClassDeclarationChecker : FirRegularClassChecker() {
                     )
                 }
 
-                primaryConstructorParameter.returnTypeRef.isInapplicableParameterType() -> {
+                primaryConstructorParameter.returnTypeRef.isInapplicableParameterType(context.session) -> {
                     reporter.reportOn(
                         primaryConstructorParameter.returnTypeRef.source,
                         FirErrors.VALUE_CLASS_HAS_INAPPLICABLE_PARAMETER_TYPE,
@@ -227,7 +226,7 @@ object FirValueClassDeclarationChecker : FirRegularClassChecker() {
                     if (it !is FirSimpleFunction) {
                         return@forEach
                     }
-                    if (it.isEquals()) equalsFromAnyOverriding = it
+                    if (it.isEquals(context.session)) equalsFromAnyOverriding = it
                     if (it.isTypedEqualsInValueClass(context.session)) typedEquals = it
                 }
                 equalsFromAnyOverriding to typedEquals
@@ -268,8 +267,8 @@ object FirValueClassDeclarationChecker : FirRegularClassChecker() {
         return isVararg || !primaryConstructorProperty.isVal || isOpen
     }
 
-    private fun FirTypeRef.isInapplicableParameterType() =
-        isUnit || isNothing
+    private fun FirTypeRef.isInapplicableParameterType(session: FirSession): Boolean =
+        coneType.fullyExpandedType(session).let { it.isUnit || it.isNothing }
 
     private fun ConeKotlinType.isGenericArrayOfTypeParameter(): Boolean {
         if (this.typeArguments.firstOrNull() is ConeStarProjection || !isPotentiallyArray())

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

@@ -20,6 +20,7 @@ import org.jetbrains.kotlin.fir.languageVersionSettings
 import org.jetbrains.kotlin.fir.references.FirErrorNamedReference
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.fir.types.FirErrorTypeRef
+import org.jetbrains.kotlin.fir.types.UnexpandedTypeCheck
 import org.jetbrains.kotlin.fir.types.coneType
 import org.jetbrains.kotlin.fir.types.isArrayType
 
@@ -50,6 +51,8 @@ object FirNamedVarargChecker : FirCallChecker() {
             val typeRef = argument.expression.typeRef
             if (typeRef is FirErrorTypeRef) return
             if (argument.expression is FirArrayOfCall) return
+
+            @OptIn(UnexpandedTypeCheck::class)
             if (allowAssignArray && typeRef.isArrayType) return
 
             if (isAnnotation) {

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

@@ -30,6 +30,7 @@ object FirNotNullAssertionChecker : FirCheckNotNullCallChecker() {
         }
         // TODO: use of Unit is subject to change.
         //  See BodyResolveComponents.typeForQualifier in ResolveUtils.kt which returns Unit for no value type.
+        @OptIn(UnexpandedTypeCheck::class)
         if (argument is FirResolvedQualifier && argument.typeRef.isUnit) {
             // Would be reported as NO_COMPANION_OBJECT
             return

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

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.fir.expressions.FirResolvedQualifier
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirTypeAliasSymbol
+import org.jetbrains.kotlin.fir.types.UnexpandedTypeCheck
 import org.jetbrains.kotlin.fir.types.isUnit
 
 object FirStandaloneQualifierChecker : FirResolvedQualifierChecker() {
@@ -26,8 +27,11 @@ object FirStandaloneQualifierChecker : FirResolvedQualifierChecker() {
         if (lastQualifiedAccess?.explicitReceiver === expression || lastQualifiedAccess?.dispatchReceiver === expression) return
         val lastGetClass = context.getClassCalls.lastOrNull()
         if (lastGetClass?.argument === expression) return
-        // Note: if it's real Unit, it will be filtered by ClassKind.OBJECT check below
+
+        // Note: if it's real Unit, it will be filtered by ClassKind.OBJECT check below in reportErrorOn
+        @OptIn(UnexpandedTypeCheck::class)
         if (!expression.typeRef.isUnit) return
+
         expression.symbol.reportErrorOn(expression.source, context, reporter)
     }
 

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/extended/RedundantReturnUnitType.kt

@@ -13,6 +13,8 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.diagnostics.reportOn
 import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
 import org.jetbrains.kotlin.fir.expressions.impl.FirSingleExpressionBlock
+import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
+import org.jetbrains.kotlin.fir.types.coneType
 import org.jetbrains.kotlin.fir.types.isUnit
 
 object RedundantReturnUnitType : FirSimpleFunctionChecker() {
@@ -23,7 +25,7 @@ object RedundantReturnUnitType : FirSimpleFunctionChecker() {
         if (declaration.source?.kind is KtFakeSourceElementKind) return
         if (returnType.annotations.isNotEmpty()) return
 
-        if (returnType.isUnit) {
+        if (returnType.coneType.fullyExpandedType(context.session).isUnit) {
             reporter.reportOn(declaration.returnTypeRef.source, FirErrors.REDUNDANT_RETURN_UNIT_TYPE, context)
         }
     }

compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeBuiltinTypeUtils.kt

@@ -45,7 +45,8 @@ val ConeKotlinType.isPrimitiveNumberOrNullableType: Boolean
 val ConeKotlinType.isArrayType: Boolean
     get() {
         return isBuiltinType(StandardClassIds.Array, false) ||
-                StandardClassIds.primitiveArrayTypeByElementType.values.any { isBuiltinType(it, false) }
+                StandardClassIds.primitiveArrayTypeByElementType.values.any { isBuiltinType(it, false) } ||
+                StandardClassIds.unsignedArrayTypeByElementType.values.any { isBuiltinType(it, false) }
     }
 
 // Same as [KotlinBuiltIns#isNonPrimitiveArray]

compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/deserialization/FirContractDeserializer.kt

@@ -16,6 +16,7 @@ import org.jetbrains.kotlin.fir.declarations.FirContractDescriptionOwner
 import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
 import org.jetbrains.kotlin.fir.diagnostics.ConeDiagnostic
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
+import org.jetbrains.kotlin.fir.types.UnexpandedTypeCheck
 import org.jetbrains.kotlin.fir.types.isBoolean
 import org.jetbrains.kotlin.metadata.ProtoBuf
 import org.jetbrains.kotlin.metadata.deserialization.isInstanceType
@@ -37,7 +38,7 @@ class FirContractDeserializer(private val c: FirDeserializationContext) :
     override fun extractVariable(
         valueParameterIndex: Int,
         owner: FirContractDescriptionOwner
-    ): KtValueParameterReference<ConeKotlinType, ConeDiagnostic>?  {
+    ): KtValueParameterReference<ConeKotlinType, ConeDiagnostic>? {
         val name: String
         val ownerFunction = owner as FirSimpleFunction
         val typeRef = if (valueParameterIndex < 0) {
@@ -49,6 +50,7 @@ class FirContractDeserializer(private val c: FirDeserializationContext) :
             parameter.returnTypeRef
         } ?: return null
 
+        @OptIn(UnexpandedTypeCheck::class)
         return if (!typeRef.isBoolean)
             KtValueParameterReference(valueParameterIndex, name)
         else

compiler/fir/fir-serialization/src/org/jetbrains/kotlin/fir/serialization/constant/FirToConstantValueTransformer.kt

@@ -196,8 +196,8 @@ internal object FirToConstantValueTransformer : FirDefaultVisitor<ConstantValue<
         functionCall: FirFunctionCall,
         data: FirToConstantValueTransformerData
     ): ConstantValue<*>? {
-        if (functionCall.isArrayOfCall) {
-            return FirArrayOfCallTransformer().transformFunctionCall(functionCall, null).accept(this, data)
+        if (functionCall.isArrayOfCall(data.session)) {
+            return FirArrayOfCallTransformer().transformFunctionCall(functionCall, data.session).accept(this, data)
         }
         return visitQualifiedAccessExpression(functionCall, data)
     }
@@ -289,7 +289,7 @@ internal object FirToConstantValueChecker : FirDefaultVisitor<Boolean, FirSessio
     }
 
     override fun visitFunctionCall(functionCall: FirFunctionCall, data: FirSession): Boolean {
-        if (functionCall.isArrayOfCall) return functionCall.arguments.all { it.accept(this, data) }
+        if (functionCall.isArrayOfCall(data)) return functionCall.arguments.all { it.accept(this, data) }
         return visitQualifiedAccessExpression(functionCall, data)
     }
 

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/ClassMemberGenerator.kt

@@ -364,6 +364,7 @@ internal class ClassMemberGenerator(
              *   constructor() : this(10) // <---- this call, IrDelegatingConstructorCall
              * }
              */
+            @OptIn(UnexpandedTypeCheck::class)
             if ((constructor.isFromEnumClass || constructor.returnTypeRef.isEnum) && this.isSuper) {
                 IrEnumConstructorCallImpl(
                     startOffset, endOffset,

compiler/fir/providers/src/org/jetbrains/kotlin/fir/declarations/OperatorFunctionChecks.kt

@@ -13,6 +13,7 @@ import org.jetbrains.kotlin.fir.declarations.utils.isSuspend
 import org.jetbrains.kotlin.fir.languageVersionSettings
 import org.jetbrains.kotlin.fir.resolve.ScopeSession
 import org.jetbrains.kotlin.fir.resolve.defaultType
+import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.resolve.toFirRegularClassSymbol
 import org.jetbrains.kotlin.fir.scopes.overriddenFunctions
 import org.jetbrains.kotlin.fir.types.*
@@ -45,7 +46,7 @@ object OperatorFunctionChecks {
         checkFor(
             OperatorNameConventions.SET,
             Checks.memberOrExtension, Checks.ValueParametersCount.atLeast(2),
-            Checks.simple("last parameter should not have a default value or be a vararg") {
+            Checks.simple("last parameter should not have a default value or be a vararg") { it, _ ->
                 it.valueParameters.lastOrNull()?.let { param ->
                     param.defaultValue == null && !param.isVararg
                 } == true
@@ -161,9 +162,9 @@ private abstract class Check {
 }
 
 private object Checks {
-    fun simple(message: String, predicate: (FirSimpleFunction) -> Boolean) = object : Check() {
+    fun simple(message: String, predicate: (FirSimpleFunction, FirSession) -> Boolean) = object : Check() {
         override fun check(function: FirSimpleFunction, session: FirSession, scopeSession: ScopeSession?): String? =
-            message.takeIf { !predicate(function) }
+            message.takeIf { !predicate(function, session) }
     }
 
     fun full(message: String, predicate: (FirSession, FirSimpleFunction) -> Boolean) = object : Check() {
@@ -171,51 +172,51 @@ private object Checks {
             message.takeIf { !predicate(session, function) }
     }
 
-    val memberOrExtension = simple("must be a member or an extension function") {
+    val memberOrExtension = simple("must be a member or an extension function") { it, _ ->
         it.dispatchReceiverType != null || it.receiverParameter != null
     }
 
-    val member = simple("must be a member function") {
+    val member = simple("must be a member function") { it, _ ->
         it.dispatchReceiverType != null
     }
 
-    val nonSuspend = simple("must not be suspend") {
+    val nonSuspend = simple("must not be suspend") { it, _ ->
         !it.isSuspend
     }
 
     object ValueParametersCount {
-        fun atLeast(n: Int) = simple("must have at least $n value parameter" + (if (n > 1) "s" else "")) {
+        fun atLeast(n: Int) = simple("must have at least $n value parameter" + (if (n > 1) "s" else "")) { it, _ ->
             it.valueParameters.size >= n
         }
 
-        fun exactly(n: Int) = simple("must have exactly $n value parameters") {
+        fun exactly(n: Int) = simple("must have exactly $n value parameters") { it, _ ->
             it.valueParameters.size == n
         }
 
-        val single = simple("must have a single value parameter") {
+        val single = simple("must have a single value parameter") { it, _ ->
             it.valueParameters.size == 1
         }
 
-        val none = simple("must have no value parameters") {
+        val none = simple("must have no value parameters") { it, _ ->
             it.valueParameters.isEmpty()
         }
     }
 
     object Returns {
-        val boolean = simple("must return Boolean") {
-            it.returnTypeRef.isBoolean
+        val boolean = simple("must return Boolean") { it, session ->
+            it.returnTypeRef.coneType.fullyExpandedType(session).isBoolean
         }
 
-        val int = simple("must return Int") {
-            it.returnTypeRef.isInt
+        val int = simple("must return Int") { it, session ->
+            it.returnTypeRef.coneType.fullyExpandedType(session).isInt
         }
 
-        val unit = simple("must return Unit") {
-            it.returnTypeRef.isUnit
+        val unit = simple("must return Unit") { it, session ->
+            it.returnTypeRef.coneType.fullyExpandedType(session).isUnit
         }
     }
 
-    val noDefaultAndVarargs = simple("should not have varargs or parameters with default values") {
+    val noDefaultAndVarargs = simple("should not have varargs or parameters with default values") { it, _ ->
         it.valueParameters.all { param ->
             param.defaultValue == null && !param.isVararg
         }

compiler/fir/providers/src/org/jetbrains/kotlin/fir/declarations/ValueClassesUtils.kt

@@ -88,7 +88,10 @@ fun FirSimpleFunction.isTypedEqualsInValueClass(session: FirSession): Boolean =
             contextReceivers.isEmpty() && receiverParameter == null
                     && name == OperatorNameConventions.EQUALS
                     && this@run.isInline && valueParameters.size == 1
-                    && (returnTypeRef.isBoolean || returnTypeRef.isNothing)
-                    && valueParameters[0].returnTypeRef.coneType.let { it is ConeClassLikeType && it.replaceArgumentsWithStarProjections() == valueClassStarProjection }
+                    && returnTypeRef.coneType.fullyExpandedType(session).let {
+                it.isBoolean || it.isNothing
+            } && valueParameters[0].returnTypeRef.coneType.let {
+                it is ConeClassLikeType && it.replaceArgumentsWithStarProjections() == valueClassStarProjection
+            }
         }
-    } ?: false
+    } == true

compiler/fir/providers/src/org/jetbrains/kotlin/fir/declarations/declarationUtils.kt

@@ -17,7 +17,9 @@ import org.jetbrains.kotlin.fir.symbols.impl.*
 import org.jetbrains.kotlin.fir.types.ConeClassLikeType
 import org.jetbrains.kotlin.fir.types.coneType
 import org.jetbrains.kotlin.fir.types.coneTypeSafe
+import org.jetbrains.kotlin.fir.types.isNullableAny
 import org.jetbrains.kotlin.fir.types.toSymbol
+import org.jetbrains.kotlin.util.OperatorNameConventions
 
 fun FirClass.constructors(session: FirSession): List<FirConstructorSymbol> {
     val result = mutableListOf<FirConstructorSymbol>()
@@ -93,3 +95,12 @@ private fun FirFunction.containsDefaultValue(index: Int): Boolean = valueParamet
 
 fun FirFunction.itOrExpectHasDefaultParameterValue(index: Int): Boolean =
     containsDefaultValue(index) || symbol.getSingleExpectForActualOrNull()?.fir?.containsDefaultValue(index) == true
+
+fun FirSimpleFunction.isEquals(session: FirSession): Boolean {
+    if (name != OperatorNameConventions.EQUALS) return false
+    if (valueParameters.size != 1) return false
+    if (contextReceivers.isNotEmpty()) return false
+    if (receiverParameter != null) return false
+    val parameter = valueParameters.first()
+    return parameter.returnTypeRef.coneType.fullyExpandedType(session).isNullableAny
+}

compiler/fir/providers/src/org/jetbrains/kotlin/fir/scopes/impl/FirClassAnySynthesizedMemberScope.kt

@@ -24,6 +24,7 @@ import org.jetbrains.kotlin.fir.declarations.builder.FirSimpleFunctionBuilder
 import org.jetbrains.kotlin.fir.declarations.builder.buildSimpleFunction
 import org.jetbrains.kotlin.fir.declarations.builder.buildValueParameter
 import org.jetbrains.kotlin.fir.declarations.impl.FirResolvedDeclarationStatusImpl
+import org.jetbrains.kotlin.fir.declarations.isEquals
 import org.jetbrains.kotlin.fir.resolve.ScopeSession
 import org.jetbrains.kotlin.fir.resolve.defaultType
 import org.jetbrains.kotlin.fir.resolve.lookupSuperTypes
@@ -46,7 +47,7 @@ import org.jetbrains.kotlin.utils.addToStdlib.shouldNotBeCalled
  * This declared scope wrapper is created for data/value classes and provides Any method stubs, if necessary
  */
 class FirClassAnySynthesizedMemberScope(
-    session: FirSession,
+    private val session: FirSession,
     private val declaredMemberScope: FirContainingNamesAwareScope,
     klass: FirRegularClass,
     scopeSession: ScopeSession,
@@ -118,7 +119,7 @@ class FirClassAnySynthesizedMemberScope(
             }
             else -> {
                 lazyResolveToPhase(FirResolvePhase.TYPES)
-                fir.isEquals()
+                fir.isEquals(session)
             }
         }
     }

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

@@ -54,16 +54,17 @@ import kotlin.contracts.contract
 fun FirAnonymousFunction.shouldReturnUnit(returnStatements: Collection<FirExpression>): Boolean =
     isLambda && returnStatements.any { it is FirUnitExpression }
 
-fun FirAnonymousFunction.addReturnToLastStatementIfNeeded() {
+fun FirAnonymousFunction.addReturnToLastStatementIfNeeded(session: FirSession) {
     // If this lambda's resolved, expected return type is Unit, we don't need an explicit return statement.
     // During conversion (to backend IR), the last expression will be coerced to Unit if needed.
-    if (returnTypeRef.isUnit) return
+    if (returnTypeRef.coneType.fullyExpandedType(session).isUnit) return
 
     val body = this.body ?: return
     val lastStatement = body.statements.lastOrNull() as? FirExpression ?: return
     if (lastStatement is FirReturnExpression) return
 
     val returnType = (body.typeRef as? FirResolvedTypeRef) ?: return
+    @OptIn(UnexpandedTypeCheck::class)
     if (returnType.isNothing) return
 
     val returnTarget = FirFunctionTarget(null, isLambda = isLambda).also { it.bind(this) }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/CallableReferenceResolution.kt

@@ -21,6 +21,7 @@ import org.jetbrains.kotlin.fir.resolve.BodyResolveComponents
 import org.jetbrains.kotlin.fir.resolve.DoubleColonLHS
 import org.jetbrains.kotlin.fir.resolve.createFunctionType
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeUnsupportedCallableReferenceTarget
+import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.resolve.inference.extractInputOutputTypesFromCallableReferenceExpectedType
 import org.jetbrains.kotlin.fir.resolve.inference.model.ConeArgumentConstraintPosition
 import org.jetbrains.kotlin.fir.resolve.scope
@@ -248,10 +249,14 @@ private fun BodyResolveComponents.getCallableReferenceAdaptation(
         }
     }
 
-    val coercionStrategy = if (returnExpectedType.isUnitOrFlexibleUnit && !function.returnTypeRef.isUnit)
-        CoercionStrategy.COERCION_TO_UNIT
-    else
-        CoercionStrategy.NO_COERCION
+    val returnTypeRef = function.returnTypeRef
+    val coercionStrategy =
+        if (returnExpectedType.isUnitOrFlexibleUnit &&
+            returnTypeRef.coneTypeSafe<ConeKotlinType>()?.fullyExpandedType(session)?.isUnit != true
+        )
+            CoercionStrategy.COERCION_TO_UNIT
+        else
+            CoercionStrategy.NO_COERCION
 
     val adaptedArguments = if (expectedType.isBaseTypeForNumberedReferenceTypes)
         emptyMap()

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/FirDataFlowAnalyzer.kt

@@ -536,7 +536,7 @@ abstract class FirDataFlowAnalyzer(
 
         return session.declaredMemberScope(this, memberRequiredPhase = FirResolvePhase.STATUS)
             .getFunctions(OperatorNameConventions.EQUALS)
-            .any { it.fir.isEquals() }
+            .any { it.fir.isEquals(session) }
     }
 
     // ----------------------------------- Jump -----------------------------------
@@ -1107,6 +1107,7 @@ abstract class FirDataFlowAnalyzer(
         }
     }
 
+    @OptIn(UnexpandedTypeCheck::class)
     fun exitElvis(elvisExpression: FirElvisExpression, isLhsNotNull: Boolean, callCompleted: Boolean) {
         val node = graphBuilder.exitElvis(isLhsNotNull, callCompleted)
         node.mergeIncomingFlow { flow ->

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphBuilder.kt

@@ -1065,6 +1065,7 @@ class ControlFlowGraphBuilder {
     //  it would be much easier if we could build calls after full completion only, at least for Nothing calls
     //  KT-59726
     // @returns `true` if node actually returned Nothing
+    @OptIn(UnexpandedTypeCheck::class)
     private fun completeFunctionCall(node: FunctionCallNode): Boolean {
         if (!node.fir.resultType.isNothing) return false
         val stub = StubNode(node.owner, node.level)
@@ -1082,6 +1083,7 @@ class ControlFlowGraphBuilder {
 
     // ----------------------------------- Resolvable call -----------------------------------
 
+    @OptIn(UnexpandedTypeCheck::class)
     fun exitQualifiedAccessExpression(qualifiedAccessExpression: FirQualifiedAccessExpression): QualifiedAccessNode {
         val returnsNothing = qualifiedAccessExpression.resultType.isNothing
         val node = createQualifiedAccessNode(qualifiedAccessExpression)
@@ -1093,6 +1095,7 @@ class ControlFlowGraphBuilder {
         return node
     }
 
+    @OptIn(UnexpandedTypeCheck::class)
     fun exitSmartCastExpression(smartCastExpression: FirSmartCastExpression): SmartCastExpressionExitNode {
         val returnsNothing = smartCastExpression.resultType.isNothing
         val node = createSmartCastExitNode(smartCastExpression)
@@ -1126,6 +1129,7 @@ class ControlFlowGraphBuilder {
         return argumentListSplitNodes.pop()?.also { addNewSimpleNode(it) }
     }
 
+    @OptIn(UnexpandedTypeCheck::class)
     fun exitFunctionCall(functionCall: FirFunctionCall, callCompleted: Boolean): FunctionCallNode {
         val returnsNothing = functionCall.resultType.isNothing
         val node = createFunctionCallNode(functionCall)
@@ -1171,6 +1175,7 @@ class ControlFlowGraphBuilder {
         return createThrowExceptionNode(throwExpression).also { addNonSuccessfullyTerminatingNode(it) }
     }
 
+    @OptIn(UnexpandedTypeCheck::class)
     fun exitCheckNotNullCall(checkNotNullCall: FirCheckNotNullCall, callCompleted: Boolean): CheckNotNullCallNode {
         val node = createCheckNotNullCallNode(checkNotNullCall)
         unifyDataFlowFromPostponedLambdas(node, callCompleted)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirCallCompletionResultsWriterTransformer.kt

@@ -249,7 +249,7 @@ class FirCallCompletionResultsWriterTransformer(
         }
 
         if (enableArrayOfCallTransformation) {
-            return arrayOfCallTransformer.transformFunctionCall(result, null)
+            return arrayOfCallTransformer.transformFunctionCall(result, session)
         }
 
         return result
@@ -618,7 +618,7 @@ class FirCallCompletionResultsWriterTransformer(
             session.lookupTracker?.recordTypeResolveAsLookup(result.typeRef, result.source, context.file.source)
         }
         // Have to delay this until the type is written to avoid adding a return if the type is Unit.
-        result.addReturnToLastStatementIfNeeded()
+        result.addReturnToLastStatementIfNeeded(session)
         return result
     }
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirWhenExhaustivenessTransformer.kt

@@ -214,6 +214,7 @@ private object WhenOnNullableExhaustivenessChecker : WhenExhaustivenessChecker()
     private object ConditionChecker : AbstractConditionChecker<Flags>() {
         override fun visitEqualityOperatorCall(equalityOperatorCall: FirEqualityOperatorCall, data: Flags) {
             val argument = equalityOperatorCall.arguments[1]
+            @OptIn(UnexpandedTypeCheck::class)
             if (argument.typeRef.isNullableNothing) {
                 data.containsNull = true
             }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirArrayOfCallTransformer.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.fir.resolve.transformers.body.resolve
 
 import org.jetbrains.kotlin.fir.FirElement
+import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.declarations.FirCallableDeclaration
 import org.jetbrains.kotlin.fir.declarations.FirSimpleFunction
 import org.jetbrains.kotlin.fir.expressions.*
@@ -14,7 +15,10 @@ import org.jetbrains.kotlin.fir.expressions.builder.buildArrayOfCall
 import org.jetbrains.kotlin.fir.references.FirResolvedErrorReference
 import org.jetbrains.kotlin.fir.references.FirResolvedNamedReference
 import org.jetbrains.kotlin.fir.resolve.calls.FirNamedReferenceWithCandidate
+import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
+import org.jetbrains.kotlin.fir.types.ConeKotlinType
+import org.jetbrains.kotlin.fir.types.coneTypeSafe
 import org.jetbrains.kotlin.fir.types.isArrayType
 import org.jetbrains.kotlin.fir.visitors.FirDefaultTransformer
 
@@ -23,9 +27,9 @@ import org.jetbrains.kotlin.fir.visitors.FirDefaultTransformer
  *
  * Note that arrayOf() calls only in [FirAnnotation] or the default value of annotation constructor are transformed.
  */
-class FirArrayOfCallTransformer : FirDefaultTransformer<Nothing?>() {
-    private fun toArrayOfCall(functionCall: FirFunctionCall): FirArrayOfCall? {
-        if (!functionCall.isArrayOfCall) return null
+class FirArrayOfCallTransformer : FirDefaultTransformer<FirSession>() {
+    private fun toArrayOfCall(functionCall: FirFunctionCall, session: FirSession): FirArrayOfCall? {
+        if (!functionCall.isArrayOfCall(session)) return null
         if (functionCall.calleeReference !is FirResolvedNamedReference) return null
         return buildArrayOfCall {
             source = functionCall.source
@@ -42,25 +46,25 @@ class FirArrayOfCallTransformer : FirDefaultTransformer<Nothing?>() {
         }
     }
 
-    override fun transformFunctionCall(functionCall: FirFunctionCall, data: Nothing?): FirStatement {
+    override fun transformFunctionCall(functionCall: FirFunctionCall, data: FirSession): FirStatement {
         functionCall.transformChildren(this, data)
-        return toArrayOfCall(functionCall) ?: functionCall
+        return toArrayOfCall(functionCall, data) ?: functionCall
     }
 
-    override fun <E : FirElement> transformElement(element: E, data: Nothing?): E {
+    override fun <E : FirElement> transformElement(element: E, data: FirSession): E {
         @Suppress("UNCHECKED_CAST")
         return (element.transformChildren(this, data) as E)
     }
 
     companion object {
-        val FirFunctionCall.isArrayOfCall: Boolean
-            get() {
-                val function: FirCallableDeclaration = getOriginalFunction() ?: return false
-                return function is FirSimpleFunction &&
-                        function.returnTypeRef.isArrayType &&
-                        isArrayOf(function, arguments) &&
-                        function.receiverParameter == null
-            }
+        fun FirFunctionCall.isArrayOfCall(session: FirSession): Boolean {
+            val function: FirCallableDeclaration = getOriginalFunction() ?: return false
+            val returnTypeRef = function.returnTypeRef
+            return function is FirSimpleFunction &&
+                    returnTypeRef.coneTypeSafe<ConeKotlinType>()?.fullyExpandedType(session)?.isArrayType == true &&
+                    isArrayOf(function, arguments) &&
+                    function.receiverParameter == null
+        }
 
         private val arrayOfNames = hashSetOf("kotlin/arrayOf") +
                 hashSetOf(

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirDeclarationsResolveTransformer.kt

@@ -860,7 +860,7 @@ open class FirDeclarationsResolveTransformer(
 
         lambda.replaceTypeRef(lambda.constructFunctionTypeRef(session, resolvedLambdaAtom?.expectedFunctionTypeKind))
         session.lookupTracker?.recordTypeResolveAsLookup(lambda.typeRef, lambda.source, context.file.source)
-        lambda.addReturnToLastStatementIfNeeded()
+        lambda.addReturnToLastStatementIfNeeded(session)
         return lambda
     }
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt

@@ -451,7 +451,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
             addReceiversFromExtensions(result)
 
             if (enableArrayOfCallTransformation) {
-                return arrayOfCallTransformer.transformFunctionCall(result, null)
+                return arrayOfCallTransformer.transformFunctionCall(result, session)
             }
             return result
         }

compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/CFGNode.kt

@@ -16,6 +16,7 @@ import org.jetbrains.kotlin.fir.resolve.dfa.PersistentFlow
 import org.jetbrains.kotlin.fir.resolve.dfa.controlFlowGraph
 import org.jetbrains.kotlin.fir.symbols.impl.FirPropertySymbol
 import org.jetbrains.kotlin.fir.types.FirTypeRef
+import org.jetbrains.kotlin.fir.types.UnexpandedTypeCheck
 import org.jetbrains.kotlin.fir.types.coneType
 import org.jetbrains.kotlin.fir.types.impl.FirImplicitNothingTypeRef
 import org.jetbrains.kotlin.fir.types.isNothing
@@ -815,6 +816,8 @@ object FirStub : FirExpression() {
     override fun <D> transformAnnotations(transformer: FirTransformer<D>, data: D): FirExpression = this
     override fun <D> transformChildren(transformer: FirTransformer<D>, data: D): FirElement = this
     override fun replaceAnnotations(newAnnotations: List<FirAnnotation>) { assert(newAnnotations.isEmpty()) }
+
+    @OptIn(UnexpandedTypeCheck::class)
     override fun replaceTypeRef(newTypeRef: FirTypeRef) { assert(newTypeRef.isNothing) }
 }
 

compiler/fir/tree/src/org/jetbrains/kotlin/fir/symbols/impl/FirCallableSymbol.kt

@@ -96,12 +96,3 @@ val FirCallableSymbol<*>.isExtension: Boolean
         is FirProperty -> fir.receiverParameter != null
         is FirVariable -> false
     }
-
-fun FirSimpleFunction.isEquals(): Boolean {
-    if (name != OperatorNameConventions.EQUALS) return false
-    if (valueParameters.size != 1) return false
-    if (contextReceivers.isNotEmpty()) return false
-    if (receiverParameter != null) return false
-    val parameter = valueParameters.first()
-    return parameter.returnTypeRef.isNullableAny
-}

compiler/fir/tree/src/org/jetbrains/kotlin/fir/types/FirTypeUtils.kt

@@ -34,15 +34,40 @@ val FirTypeRef.coneType: ConeKotlinType
 val FirTypeRef.coneTypeOrNull: ConeKotlinType?
     get() = coneTypeSafe()
 
+@RequiresOptIn(
+    "This type check never expands type aliases. Use with care (probably Ok for expression & constructor types). " +
+            "Generally this.coneType.fullyExpandedType(session).isSomeType is better"
+)
+annotation class UnexpandedTypeCheck
+
+@UnexpandedTypeCheck
 val FirTypeRef.isAny: Boolean get() = isBuiltinType(StandardClassIds.Any, false)
+
+@UnexpandedTypeCheck
 val FirTypeRef.isNullableAny: Boolean get() = isBuiltinType(StandardClassIds.Any, true)
+
+@UnexpandedTypeCheck
 val FirTypeRef.isNothing: Boolean get() = isBuiltinType(StandardClassIds.Nothing, false)
+
+@UnexpandedTypeCheck
 val FirTypeRef.isNullableNothing: Boolean get() = isBuiltinType(StandardClassIds.Nothing, true)
+
+@UnexpandedTypeCheck
 val FirTypeRef.isUnit: Boolean get() = isBuiltinType(StandardClassIds.Unit, false)
+
+@UnexpandedTypeCheck
 val FirTypeRef.isBoolean: Boolean get() = isBuiltinType(StandardClassIds.Boolean, false)
+
+@UnexpandedTypeCheck
 val FirTypeRef.isInt: Boolean get() = isBuiltinType(StandardClassIds.Int, false)
+
+@UnexpandedTypeCheck
 val FirTypeRef.isString: Boolean get() = isBuiltinType(StandardClassIds.String, false)
+
+@UnexpandedTypeCheck
 val FirTypeRef.isEnum: Boolean get() = isBuiltinType(StandardClassIds.Enum, false)
+
+@UnexpandedTypeCheck
 val FirTypeRef.isArrayType: Boolean
     get() =
         isBuiltinType(StandardClassIds.Array, false)