[FIR] Replace usages of FirExpression.typeRef with coneTypeOrNull

#KT-59855 Fixed

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirExpressionTypeProvider.kt

@@ -72,7 +72,7 @@ internal class KtFirExpressionTypeProvider(
             // For unresolved `super`, we manually create an intersection type so that IDE features like completion can work correctly.
             val containingClass = (fir.dispatchReceiver as? FirThisReceiverExpression)?.calleeReference?.boundSymbol as? FirClassSymbol<*>
 
-            if (fir.calleeReference is FirSuperReference && fir.typeRef is FirErrorTypeRef && containingClass != null) {
+            if (fir.calleeReference is FirSuperReference && fir.coneTypeOrNull is ConeErrorType && containingClass != null) {
                 val superTypes = containingClass.resolvedSuperTypes
                 when (superTypes.size) {
                     0 -> analysisSession.builtinTypes.ANY
@@ -214,9 +214,7 @@ internal class KtFirExpressionTypeProvider(
     private fun getExpectedTypeByTypeCast(expression: PsiElement): KtType? {
         val typeCastExpression =
             expression.unwrapQualified<KtBinaryExpressionWithTypeRHS> { castExpr, expr -> castExpr.left == expr } ?: return null
-        with(analysisSession) {
-            return typeCastExpression.right?.getKtType()
-        }
+        return getKtExpressionType(typeCastExpression)
     }
 
     private fun getExpectedTypeOfFunctionParameter(expression: PsiElement): KtType? {

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/evaluate/FirCompileTimeConstantEvaluator.kt

@@ -178,13 +178,13 @@ internal object FirCompileTimeConstantEvaluator {
 
         val opr1 = evaluate(functionCall.explicitReceiver, mode) ?: return null
         opr1.evaluate(function)?.let {
-            return it.adjustType(functionCall.type)
+            return it.adjustType(functionCall.coneTypeOrNull)
         }
 
         val argument = functionCall.arguments.firstOrNull() ?: return null
         val opr2 = evaluate(argument, mode) ?: return null
         opr1.evaluate(function, opr2)?.let {
-            return it.adjustType(functionCall.type)
+            return it.adjustType(functionCall.coneTypeOrNull)
         }
         return null
     }
@@ -207,7 +207,7 @@ internal object FirCompileTimeConstantEvaluator {
             }
         // Lastly, we should preserve the resolved type of the original function call.
         return expression.apply {
-            replaceType(expectedType)
+            replaceConeTypeOrNull(expectedType)
         }
     }
 

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

@@ -422,7 +422,7 @@ internal object FirReferenceResolveHelper {
         // accessing the `super` property on `this`, hence this weird looking if condition. In addition, the current class type is available
         // from the dispatch receiver `this`.
         if (expression is KtLabelReferenceExpression && fir is FirPropertyAccessExpression && fir.calleeReference is FirSuperReference) {
-            return listOfNotNull(fir.dispatchReceiver.type?.toTargetSymbol(session, symbolBuilder))
+            return listOfNotNull(fir.dispatchReceiver.coneTypeOrNull?.toTargetSymbol(session, symbolBuilder))
         }
         val receiverOrImplicitInvoke = if (fir is FirImplicitInvokeCall) {
             fir.explicitReceiver?.unwrapSmartcastExpression()
@@ -733,7 +733,7 @@ internal object FirReferenceResolveHelper {
         session: FirSession,
         symbolBuilder: KtSymbolByFirBuilder
     ): Collection<KtSymbol> {
-        val type = fir.type ?: return emptyList()
+        val type = fir.coneTypeOrNull ?: return emptyList()
         return listOfNotNull(type.toTargetSymbol(session, symbolBuilder))
     }
 

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/file/structure/FirElementsRecorder.kt

@@ -218,7 +218,7 @@ internal open class FirElementsRecorder : FirVisitor<Unit, MutableMap<KtElement,
             convertedValue as T,
             setType = false
         ).also {
-            it.replaceTypeRef(original.typeRef)
+            it.replaceConeTypeOrNull(original.coneTypeOrNull)
         }
     }
 

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/stubBased/deserialization/StubBasedAnnotationDeserializer.kt

@@ -36,7 +36,6 @@ import org.jetbrains.kotlin.psi.stubs.impl.KotlinClassTypeBean
 import org.jetbrains.kotlin.psi.stubs.impl.KotlinPropertyStubImpl
 import org.jetbrains.kotlin.types.ConstantValueKind
 import org.jetbrains.kotlin.utils.exceptions.errorWithAttachment
-import org.jetbrains.kotlin.utils.exceptions.withPsiEntry
 
 class StubBasedAnnotationDeserializer(
     private val session: FirSession,
@@ -109,23 +108,20 @@ class StubBasedAnnotationDeserializer(
                 source = KtRealPsiSourceElement(sourceElement)
                 val lookupTag = (value.value as KClassValue.Value.NormalClass).classId.toLookupTag()
                 val referencedType = lookupTag.constructType(ConeTypeProjection.EMPTY_ARRAY, isNullable = false)
-                val resolvedTypeRef = buildResolvedTypeRef {
-                    type = StandardClassIds.KClass.constructClassLikeType(arrayOf(referencedType), false)
-                }
+                val resolvedType = StandardClassIds.KClass.constructClassLikeType(arrayOf(referencedType), false)
                 argumentList = buildUnaryArgumentList(
                     buildClassReferenceExpression {
                         classTypeRef = buildResolvedTypeRef { type = referencedType }
-                        typeRef = resolvedTypeRef
+                        coneTypeOrNull = resolvedType
                     }
                 )
+                coneTypeOrNull = resolvedType
             }
             is ArrayValue -> {
                 buildArrayLiteral {
                     source = KtRealPsiSourceElement(sourceElement)
-                    typeRef = buildResolvedTypeRef {
-                        // Not quite precise, yet doesn't require annotation resolution
-                        type = (inferArrayValueType(value.value) ?: session.builtinTypes.anyType.type).createArrayType()
-                    }
+                    // Not quite precise, yet doesn't require annotation resolution
+                    coneTypeOrNull = (inferArrayValueType(value.value) ?: session.builtinTypes.anyType.type).createArrayType()
 
                     argumentList = buildArgumentList {
                         value.value.mapTo(arguments) { resolveValue(sourceElement, it) }
@@ -208,7 +204,7 @@ class StubBasedAnnotationDeserializer(
             kind,
             value,
             setType = true
-        ).apply { this.replaceTypeRef(typeRef) }
+        ).apply { this.replaceConeTypeOrNull(typeRef.type) }
     }
 
     private fun PsiElement.toEnumEntryReferenceExpression(classId: ClassId, entryName: Name): FirExpression {
@@ -228,7 +224,7 @@ class StubBasedAnnotationDeserializer(
                 name = entryName
             }
             if (enumEntrySymbol != null) {
-                typeRef = enumEntrySymbol.returnTypeRef
+                coneTypeOrNull = enumEntrySymbol.returnTypeRef.coneTypeOrNull
             }
         }
     }

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/transformers/LLFirBodyLazyResolver.kt

@@ -43,7 +43,6 @@ import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.FirBodyResolve
 import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.FirResolveContextCollector
 import org.jetbrains.kotlin.fir.resolve.transformers.contracts.FirContractsDslNames
 import org.jetbrains.kotlin.fir.symbols.lazyResolveToPhase
-import org.jetbrains.kotlin.fir.types.FirResolvedTypeRef
 import org.jetbrains.kotlin.fir.resolve.dfa.cfg.isUsedInControlFlowGraphBuilderForClass
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
@@ -399,7 +398,7 @@ private val FirFunction.isCertainlyResolved: Boolean
         }
 
         val body = this.body ?: return false // Not completely sure
-        return body !is FirLazyBlock && body.typeRef is FirResolvedTypeRef
+        return body !is FirLazyBlock && body.coneTypeOrNull != null
     }
 
 private val FirVariable.initializerIfUnresolved: FirExpression?
@@ -472,4 +471,4 @@ private fun requireSameSize(old: List<FirStatement>, new: List<FirStatement>) {
 private class LLFirCodeFragmentContext(
     override val towerDataContext: FirTowerDataContext,
     override val variables: Map<FirBasedSymbol<*>, Set<ConeKotlinType>>
-) : FirCodeFragmentContext
+) : FirCodeFragmentContext

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/util/firCheckResolvedUtils.kt

@@ -19,6 +19,7 @@ import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.FirResolvable
 import org.jetbrains.kotlin.fir.expressions.impl.FirResolvedArgumentList
 import org.jetbrains.kotlin.fir.references.*
+import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.fir.types.FirImplicitTypeRef
 import org.jetbrains.kotlin.fir.types.FirResolvedTypeRef
 import org.jetbrains.kotlin.fir.types.FirTypeRef
@@ -49,6 +50,26 @@ internal inline fun checkTypeRefIsResolved(
     }
 }
 
+internal inline fun checkExpressionTypeIsResolved(
+    type: ConeKotlinType?,
+    typeName: String,
+    owner: FirElementWithResolveState,
+    extraAttachment: ExceptionAttachmentBuilder.() -> Unit = {},
+) {
+    checkWithAttachment(
+        condition = type != null,
+        message = {
+            buildString {
+                append("Expected resolved expression type")
+                append(" for $typeName of ${owner::class.simpleName}(${(owner as? FirDeclaration)?.origin})")
+            }
+        }
+    ) {
+        withFirEntry("firDeclaration", owner)
+        extraAttachment()
+    }
+}
+
 internal fun <T> checkAnnotationTypeIsResolved(annotationContainer: T) where T : FirAnnotationContainer, T : FirElementWithResolveState {
     annotationContainer.annotations.forEach { annotation ->
         checkTypeRefIsResolved(annotation.annotationTypeRef, "annotation type", owner = annotationContainer) {
@@ -59,7 +80,7 @@ internal fun <T> checkAnnotationTypeIsResolved(annotationContainer: T) where T :
 
 internal fun checkBodyIsResolved(function: FirFunction) {
     val block = function.body ?: return
-    checkTypeRefIsResolved(block.typeRef, "block type", function) {
+    checkExpressionTypeIsResolved(block.coneTypeOrNull, "block type", function) {
         withFirEntry("block", block)
     }
 }
@@ -67,7 +88,7 @@ internal fun checkBodyIsResolved(function: FirFunction) {
 internal fun checkStatementsAreResolved(script: FirScript) {
     for (statement in script.statements) {
         if (statement.isScriptStatement && statement is FirExpression) {
-            checkTypeRefIsResolved(statement.typeRef, "script statement", script) {
+            checkExpressionTypeIsResolved(statement.coneTypeOrNull, "script statement", script) {
                 withFirEntry("expression", statement)
             }
         }
@@ -114,14 +135,14 @@ internal fun checkReferenceIsResolved(
 
 internal fun checkInitializerIsResolved(variable: FirVariable) {
     val initializer = variable.initializer ?: return
-    checkTypeRefIsResolved(initializer.typeRef, "initializer type", variable) {
+    checkExpressionTypeIsResolved(initializer.coneTypeOrNull, "initializer type", variable) {
         withFirEntry("initializer", initializer)
     }
 }
 
 internal fun checkDefaultValueIsResolved(parameter: FirValueParameter) {
     val defaultValue = parameter.defaultValue ?: return
-    checkTypeRefIsResolved(defaultValue.typeRef, "default value type", parameter) {
+    checkExpressionTypeIsResolved(defaultValue.coneTypeOrNull, "default value type", parameter) {
         withFirEntry("defaultValue", defaultValue)
     }
 }
@@ -194,7 +215,7 @@ internal fun <T> checkAnnotationArgumentsMappingIsResolved(
         }
 
         for (argument in annotation.argumentMapping.mapping.values) {
-            checkTypeRefIsResolved(argument.typeRef, "annotation argument", annotationContainer) {
+            checkExpressionTypeIsResolved(argument.coneTypeOrNull, "annotation argument", annotationContainer) {
                 withFirEntry("firAnnotation", annotation)
                 withFirEntry("firArgument", argument)
             }

analysis/low-level-api-fir/testdata/getOrBuildFir/invalidCode/javaClassLiteral.txt

@@ -9,7 +9,7 @@ FIR FILE:
 FILE: [ResolvedTo(IMPORTS)] javaClassLiteral.kt
     public final [ResolvedTo(BODY_RESOLVE)] fun main([ResolvedTo(BODY_RESOLVE)] args: R|kotlin/Array<kotlin/String>|): R|kotlin/Unit| {
         [ResolvedTo(BODY_RESOLVE)] lval anyClass: R|kotlin/Any| = R|kotlin/Any.Any|()
-        R|/funOne|(<ERROR TYPE REF: Qualified expression with unexpected selector>ERROR_EXPR(Incorrect selector expression)R|<local>/anyClass|)
+        R|/funOne|(ERROR_EXPR(Incorrect selector expression)R|<local>/anyClass|)
     }
     public final [ResolvedTo(CONTRACTS)] fun funOne([ResolvedTo(CONTRACTS)] x: R|kotlin/Any|): R|kotlin/Unit| {
     }

analysis/low-level-api-fir/testdata/getOrBuildFir/qualifiedExpressions/qualifiedPartOfQualifiedCallUnresolved.txt

@@ -14,7 +14,7 @@ FILE: [ResolvedTo(IMPORTS)] qualifiedPartOfQualifiedCallUnresolved.kt
 
         public final [ResolvedTo(BODY_RESOLVE)] fun handleLeftBracketInFragment(): R|kotlin/Unit| {
              {
-                [ResolvedTo(BODY_RESOLVE)] lval <receiver>: <ERROR TYPE REF: Unresolved name: peek> = <Unresolved name: peek>#()
+                [ResolvedTo(BODY_RESOLVE)] lval <receiver>: R|ERROR CLASS: Unresolved name: peek| = <Unresolved name: peek>#()
                 [ResolvedTo(BODY_RESOLVE)] lval <unary>: <ERROR TYPE REF: Unresolved name: braceBalance> = R|<local>/<receiver>|.<Unresolved name: braceBalance>#
                 R|<local>/<receiver>|.<Unresolved name: braceBalance># = R|<local>/<unary>|.<Unresolved name: inc>#()
                 R|<local>/<unary>|

analysis/low-level-api-fir/testdata/getOrBuildFir/qualifiedExpressions/qualifiedPartOfQualifiedCallUnresolvedScript.txt

@@ -18,7 +18,7 @@ FILE: [ResolvedTo(IMPORTS)] qualifiedPartOfQualifiedCallUnresolvedScript.kts
 
             public final [ResolvedTo(BODY_RESOLVE)] fun handleLeftBracketInFragment(): R|kotlin/Unit| {
                  {
-                    [ResolvedTo(BODY_RESOLVE)] lval <receiver>: <ERROR TYPE REF: Unresolved name: peek> = <Unresolved name: peek>#()
+                    [ResolvedTo(BODY_RESOLVE)] lval <receiver>: R|ERROR CLASS: Unresolved name: peek| = <Unresolved name: peek>#()
                     [ResolvedTo(BODY_RESOLVE)] lval <unary>: <ERROR TYPE REF: Unresolved name: braceBalance> = R|<local>/<receiver>|.<Unresolved name: braceBalance>#
                     R|<local>/<receiver>|.<Unresolved name: braceBalance># = R|<local>/<unary>|.<Unresolved name: inc>#()
                     R|<local>/<unary>|

compiler/fir/analysis-tests/testData/resolve/problems/invalidCode.fir.txt

@@ -6,7 +6,7 @@ FILE: a.kt
 
     public abstract interface I : R|kotlin/Any| {
         public open fun <T> f(): <ERROR TYPE REF: Qualified expression with unexpected selector> {
-            ^f <ERROR TYPE REF: Qualified expression with unexpected selector>ERROR_EXPR(The expression cannot be a selector (occur after a dot))String()
+            ^f ERROR_EXPR(The expression cannot be a selector (occur after a dot))String()
         }
 
         public final class C : R|b/I| {

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

@@ -17,6 +17,6 @@ import org.jetbrains.kotlin.fir.types.toSymbol
 object FirJsModuleGetClassCallChecker : FirGetClassCallChecker() {
     override fun check(expression: FirGetClassCall, context: CheckerContext, reporter: DiagnosticReporter) {
         val callee = expression.argument.coneTypeOrNull?.toSymbol(context.session) ?: return
-        checkJsModuleUsage(callee, context, reporter, expression.argument.typeRef.source ?: expression.source)
+        checkJsModuleUsage(callee, context, reporter, expression.source)
     }
 }

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

@@ -22,7 +22,6 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.utils.fromPrimaryConstructor
 import org.jetbrains.kotlin.fir.declarations.utils.hasBackingField
-import org.jetbrains.kotlin.fir.delegatedWrapperData
 import org.jetbrains.kotlin.fir.expressions.FirAnnotation
 import org.jetbrains.kotlin.fir.languageVersionSettings
 import org.jetbrains.kotlin.fir.packageFqName
@@ -79,7 +78,7 @@ object FirAnnotationChecker : FirBasicDeclarationChecker() {
             val receiverParameter = declaration.receiverParameter
             if (receiverParameter != null) {
                 for (receiverAnnotation in receiverParameter.annotations) {
-                    reportIfMfvc(context, reporter, receiverAnnotation, "receivers", receiverParameter.typeRef)
+                    reportIfMfvc(context, reporter, receiverAnnotation, "receivers", receiverParameter.typeRef.coneType)
                 }
             }
         }
@@ -103,7 +102,13 @@ object FirAnnotationChecker : FirBasicDeclarationChecker() {
         }
     }
 
-    private fun reportIfMfvc(context: CheckerContext, reporter: DiagnosticReporter, annotation: FirAnnotation, hint: String, type: FirTypeRef) {
+    private fun reportIfMfvc(
+        context: CheckerContext,
+        reporter: DiagnosticReporter,
+        annotation: FirAnnotation,
+        hint: String,
+        type: ConeKotlinType,
+    ) {
         if (type.needsMultiFieldValueClassFlattening(context.session)) {
             reporter.reportOn(annotation.source, FirErrors.ANNOTATION_ON_ILLEGAL_MULTI_FIELD_VALUE_CLASS_TYPED_TARGET, hint, context)
         }
@@ -120,7 +125,8 @@ object FirAnnotationChecker : FirBasicDeclarationChecker() {
 
         val (hint, type) = when (annotation.useSiteTarget) {
             FIELD -> "fields" to ((declaration as? FirBackingField)?.returnTypeRef ?: return)
-            PROPERTY_DELEGATE_FIELD -> "delegate fields" to ((declaration as? FirBackingField)?.propertySymbol?.delegate?.typeRef ?: return)
+            PROPERTY_DELEGATE_FIELD -> "delegate fields" to ((declaration as? FirBackingField)?.propertySymbol?.delegate?.coneTypeOrNull
+                ?: return)
             RECEIVER -> "receivers" to ((declaration as? FirCallableDeclaration)?.receiverParameter?.typeRef ?: return)
             FILE, PROPERTY, PROPERTY_GETTER, PROPERTY_SETTER, CONSTRUCTOR_PARAMETER, SETTER_PARAMETER, null -> when {
                 declaration is FirProperty && !declaration.isLocal -> {
@@ -141,7 +147,7 @@ object FirAnnotationChecker : FirBasicDeclarationChecker() {
                 else -> return
             }
         }
-        reportIfMfvc(context, reporter, annotation, hint, type)
+        reportIfMfvc(context, reporter, annotation, hint, type as? ConeKotlinType ?: (type as FirTypeRef).coneType)
     }
 
     private fun checkAnnotationTarget(

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

@@ -15,11 +15,8 @@ import org.jetbrains.kotlin.fir.declarations.utils.*
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.SymbolInternals
 import org.jetbrains.kotlin.fir.symbols.impl.*
-import org.jetbrains.kotlin.fir.types.FirTypeRef
-import org.jetbrains.kotlin.fir.types.coneType
+import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.impl.FirImplicitUnitTypeRef
-import org.jetbrains.kotlin.fir.types.isNullable
-import org.jetbrains.kotlin.fir.types.typeContext
 
 internal fun isInsideExpectClass(containingClass: FirClass, context: CheckerContext): Boolean {
     return isInsideSpecificClass(containingClass, context) { klass -> klass is FirRegularClass && klass.isExpect }
@@ -102,8 +99,10 @@ fun FirClassSymbol<*>.primaryConstructorSymbol(session: FirSession): FirConstruc
     return fir.primaryConstructorIfAny(session)
 }
 
-fun FirTypeRef.needsMultiFieldValueClassFlattening(session: FirSession) = with(session.typeContext) {
-    coneType.typeConstructor().isMultiFieldValueClass() && !coneType.isNullable
+fun FirTypeRef.needsMultiFieldValueClassFlattening(session: FirSession): Boolean = coneType.needsMultiFieldValueClassFlattening(session)
+
+fun ConeKotlinType.needsMultiFieldValueClassFlattening(session: FirSession) = with(session.typeContext) {
+    typeConstructor().isMultiFieldValueClass() && !isNullable
 }
 
 val FirCallableSymbol<*>.hasExplicitReturnType: Boolean

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

@@ -44,12 +44,11 @@ object FirNamedVarargChecker : FirCallChecker() {
                 }
                 return
             }
-            val typeRef = argument.expression.typeRef
-            if (typeRef is FirErrorTypeRef) return
+            val type = argument.expression.coneTypeOrNull
+            if (type is ConeErrorType) return
             if (argument.expression is FirArrayLiteral) return
 
-            @OptIn(UnexpandedTypeCheck::class)
-            if (allowAssignArray && typeRef.isArrayType) return
+            if (allowAssignArray && type?.isArrayType == true) return
 
             if (isAnnotation) {
                 reporter.reportOn(

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

@@ -5,16 +5,16 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers.expression
 
-import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
-import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.fir.expressions.FirCallableReferenceAccess
 import org.jetbrains.kotlin.fir.expressions.FirQualifiedAccessExpression
 import org.jetbrains.kotlin.fir.expressions.FirResolvedReifiedParameterReference
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeTypeParameterInQualifiedAccess
-import org.jetbrains.kotlin.fir.types.FirErrorTypeRef
-import org.jetbrains.kotlin.fir.types.FirTypeRef
+import org.jetbrains.kotlin.fir.types.ConeErrorType
+import org.jetbrains.kotlin.fir.types.ConeKotlinType
 
 object FirTypeParameterInQualifiedAccessChecker : FirQualifiedAccessExpressionChecker() {
     override fun check(expression: FirQualifiedAccessExpression, context: CheckerContext, reporter: DiagnosticReporter) {
@@ -36,7 +36,7 @@ object FirTypeParameterInQualifiedAccessChecker : FirQualifiedAccessExpressionCh
         val secondLast = context.callsOrAssignments.elementAtOrNull(context.callsOrAssignments.size - 2)
         if (secondLast is FirQualifiedAccessExpression && secondLast.explicitReceiver == expression) return
 
-        val diagnostic = expression.typeRef.coneTypeParameterInQualifiedAccess ?: return
+        val diagnostic = expression.coneTypeOrNull?.coneTypeParameterInQualifiedAccess ?: return
         val source = expression.source ?: return
         reporter.reportOn(source, FirErrors.TYPE_PARAMETER_IS_NOT_AN_EXPRESSION, diagnostic.symbol, context)
     }
@@ -49,7 +49,7 @@ object FirTypeParameterInQualifiedAccessChecker : FirQualifiedAccessExpressionCh
         val explicitReceiver = expression.explicitReceiver
         val typeParameterSymbol =
             (explicitReceiver as? FirResolvedReifiedParameterReference)?.symbol
-                ?: explicitReceiver?.typeRef?.coneTypeParameterInQualifiedAccess?.symbol
+                ?: explicitReceiver?.coneTypeOrNull?.coneTypeParameterInQualifiedAccess?.symbol
                 ?: return
         if (expression is FirCallableReferenceAccess) {
             reporter.reportOn(expression.source, FirErrors.CALLABLE_REFERENCE_LHS_NOT_A_CLASS, context)
@@ -58,6 +58,6 @@ object FirTypeParameterInQualifiedAccessChecker : FirQualifiedAccessExpressionCh
         }
     }
 
-    private val FirTypeRef.coneTypeParameterInQualifiedAccess: ConeTypeParameterInQualifiedAccess?
-        get() = (this as? FirErrorTypeRef)?.diagnostic as? ConeTypeParameterInQualifiedAccess
+    private val ConeKotlinType.coneTypeParameterInQualifiedAccess: ConeTypeParameterInQualifiedAccess?
+        get() = (this as? ConeErrorType)?.diagnostic as? ConeTypeParameterInQualifiedAccess
 }

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

@@ -5,13 +5,15 @@
 
 package org.jetbrains.kotlin.fir.analysis.checkers.expression
 
-import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
-import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
 import org.jetbrains.kotlin.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.checkers.isRefinementUseless
 import org.jetbrains.kotlin.fir.analysis.checkers.shouldCheckForExactType
-import org.jetbrains.kotlin.fir.expressions.*
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors
+import org.jetbrains.kotlin.fir.expressions.FirOperation
+import org.jetbrains.kotlin.fir.expressions.FirTypeOperatorCall
+import org.jetbrains.kotlin.fir.expressions.argument
 import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.types.*
 
@@ -39,7 +41,7 @@ object FirUselessTypeOperationCallChecker : FirTypeOperatorCallChecker() {
                 FirOperation.IS -> reporter.reportOn(expression.source, FirErrors.USELESS_IS_CHECK, true, context)
                 FirOperation.NOT_IS -> reporter.reportOn(expression.source, FirErrors.USELESS_IS_CHECK, false, context)
                 FirOperation.AS, FirOperation.SAFE_AS -> {
-                    if ((arg.typeRef as? FirResolvedTypeRef)?.isFromStubType != true) {
+                    if (!expression.argFromStubType) {
                         reporter.reportOn(expression.source, FirErrors.USELESS_CAST, context)
                     }
                 }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/type/FirOptionalExpectationTypeChecker.kt

@@ -29,7 +29,7 @@ object FirOptionalExpectationTypeChecker : FirTypeRefChecker() {
         }
 
         val annotationContainer = context.annotationContainers.lastOrNull()
-        if (annotationContainer?.annotations?.any { it.typeRef == typeRef } == true) return
+        if (annotationContainer?.annotations?.any { it.annotationTypeRef == typeRef } == true) return
 
         reporter.reportOn(source, FirErrors.OPTIONAL_DECLARATION_OUTSIDE_OF_ANNOTATION_ENTRY, context)
     }

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/collectors/components/ErrorNodeDiagnosticCollectorComponent.kt

@@ -6,12 +6,12 @@
 package org.jetbrains.kotlin.fir.analysis.collectors.components
 
 import org.jetbrains.kotlin.KtFakeSourceElementKind
-import org.jetbrains.kotlin.KtSourceElement
 import org.jetbrains.kotlin.KtNodeTypes
-import org.jetbrains.kotlin.fir.FirSession
-import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.KtSourceElement
 import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.fakeElement
+import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
 import org.jetbrains.kotlin.fir.analysis.diagnostics.toFirDiagnostics
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.diagnostics.*
@@ -19,8 +19,12 @@ import org.jetbrains.kotlin.fir.expressions.*
 import org.jetbrains.kotlin.fir.references.FirErrorNamedReference
 import org.jetbrains.kotlin.fir.references.FirNamedReference
 import org.jetbrains.kotlin.fir.references.FirResolvedErrorReference
+import org.jetbrains.kotlin.fir.references.FirThisReference
 import org.jetbrains.kotlin.fir.resolve.diagnostics.*
-import org.jetbrains.kotlin.fir.types.*
+import org.jetbrains.kotlin.fir.types.ConeErrorType
+import org.jetbrains.kotlin.fir.types.FirErrorTypeRef
+import org.jetbrains.kotlin.fir.types.FirResolvedTypeRef
+import org.jetbrains.kotlin.fir.types.renderForDebugging
 
 class ErrorNodeDiagnosticCollectorComponent(
     session: FirSession,
@@ -85,7 +89,7 @@ class ErrorNodeDiagnosticCollectorComponent(
     }
 
     private fun FirExpression?.cannotBeResolved(): Boolean {
-        return when (val diagnostic = (this?.typeRef as? FirErrorTypeRef)?.diagnostic) {
+        return when (val diagnostic = (this?.coneTypeOrNull as? ConeErrorType)?.diagnostic) {
             is ConeUnresolvedNameError, is ConeInstanceAccessBeforeSuperCall, is ConeAmbiguousSuper -> true
             is ConeSimpleDiagnostic -> diagnostic.kind == DiagnosticKind.NotASupertype ||
                     diagnostic.kind == DiagnosticKind.SuperNotAvailable ||
@@ -130,6 +134,11 @@ class ErrorNodeDiagnosticCollectorComponent(
         reportFirDiagnostic(errorPrimaryConstructor.diagnostic, errorPrimaryConstructor.source, data)
     }
 
+    override fun visitThisReference(thisReference: FirThisReference, data: CheckerContext) {
+        val diagnostic = thisReference.diagnostic ?: return
+        reportFirDiagnostic(diagnostic, thisReference.source, data)
+    }
+
     private fun reportFirDiagnostic(
         diagnostic: ConeDiagnostic,
         source: KtSourceElement?,

compiler/fir/dump/src/org/jetbrains/kotlin/fir/dump/HtmlFirDump.kt

@@ -1469,7 +1469,7 @@ class HtmlFirDump internal constructor(private var linkResolver: FirLinkResolver
     }
 
     private fun FlowContent.generate(unitExpression: FirUnitExpression) {
-        generate(unitExpression.typeRef)
+        generate(unitExpression.coneType)
     }
 
     private fun FlowContent.generate(breakExpression: FirBreakExpression) {
@@ -1530,7 +1530,7 @@ class HtmlFirDump internal constructor(private var linkResolver: FirLinkResolver
     }
 
     private fun FlowContent.generate(expression: FirExpression) {
-        exprType(expression.typeRef) {
+        exprType(expression.coneType.toFirResolvedTypeRef()) {
             when (expression) {
                 is FirBlock -> generateBlockIfAny(expression)
                 is FirGetClassCall -> generate(expression)

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

@@ -271,16 +271,14 @@ abstract class AbstractAnnotationDeserializer(
                 val classId = nameResolver.getClassId(value.classId)
                 val lookupTag = classId.toLookupTag()
                 val referencedType = lookupTag.constructType(emptyArray(), isNullable = false)
-                val resolvedTypeRef = buildResolvedTypeRef {
-                    type = StandardClassIds.KClass.constructClassLikeType(arrayOf(referencedType), false)
-                }
+                val resolvedType = StandardClassIds.KClass.constructClassLikeType(arrayOf(referencedType), false)
                 argumentList = buildUnaryArgumentList(
                     buildClassReferenceExpression {
                         classTypeRef = buildResolvedTypeRef { type = referencedType }
-                        typeRef = resolvedTypeRef
+                        coneTypeOrNull = resolvedType
                     }
                 )
-                typeRef = resolvedTypeRef
+                coneTypeOrNull = resolvedType
             }
             ENUM -> buildPropertyAccessExpression {
                 val classId = nameResolver.getClassId(value.classId)
@@ -300,7 +298,7 @@ abstract class AbstractAnnotationDeserializer(
                     name = entryName
                 }
                 if (enumEntrySymbol != null) {
-                    typeRef = enumEntrySymbol.returnTypeRef
+                    coneTypeOrNull = enumEntrySymbol.returnTypeRef.coneTypeOrNull
                 }
             }
             ARRAY -> {
@@ -309,9 +307,7 @@ abstract class AbstractAnnotationDeserializer(
                     argumentList = buildArgumentList {
                         value.arrayElementList.mapTo(arguments) { resolveValue(it, nameResolver) { expectedArrayElementType } }
                     }
-                    typeRef = buildResolvedTypeRef {
-                        type = expectedArrayElementType.createArrayType()
-                    }
+                    coneTypeOrNull = expectedArrayElementType.createArrayType()
                 }
             }
 
@@ -320,6 +316,6 @@ abstract class AbstractAnnotationDeserializer(
     }
 
     private fun <T> const(kind: ConstantValueKind<T>, value: T, typeRef: FirResolvedTypeRef): FirConstExpression<T> {
-        return buildConstExpression(null, kind, value, setType = true).apply { this.replaceTypeRef(typeRef) }
+        return buildConstExpression(null, kind, value, setType = true).apply { this.replaceConeTypeOrNull(typeRef.coneType) }
     }
 }

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

@@ -17,7 +17,6 @@ import org.jetbrains.kotlin.fir.references.builder.buildResolvedNamedReference
 import org.jetbrains.kotlin.fir.resolve.providers.getClassDeclaredPropertySymbols
 import org.jetbrains.kotlin.fir.resolve.providers.symbolProvider
 import org.jetbrains.kotlin.fir.types.ConeTypeProjection
-import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
 import org.jetbrains.kotlin.fir.types.impl.ConeClassLikeTypeImpl
 import org.jetbrains.kotlin.fir.types.toLookupTag
 
@@ -44,9 +43,7 @@ fun FirEnumEntryDeserializedAccessExpression.toQualifiedPropertyAccessExpression
             }
         }
 
-        typeRef = buildResolvedTypeRef {
-            type = ConeClassLikeTypeImpl(
-                enumClassId.toLookupTag(), ConeTypeProjection.EMPTY_ARRAY, isNullable = false
-            )
-        }
+        coneTypeOrNull = ConeClassLikeTypeImpl(
+            enumClassId.toLookupTag(), ConeTypeProjection.EMPTY_ARRAY, isNullable = false
+        )
     }

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

@@ -25,6 +25,7 @@ import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.*
 import org.jetbrains.kotlin.fir.toEffectiveVisibility
 import org.jetbrains.kotlin.fir.types.ConeLookupTagBasedType
+import org.jetbrains.kotlin.fir.types.FirResolvedTypeRef
 import org.jetbrains.kotlin.fir.types.FirTypeRef
 import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
 import org.jetbrains.kotlin.fir.types.coneType
@@ -469,7 +470,7 @@ class FirMemberDeserializer(private val c: FirDeserializationContext) {
 
             proto.contextReceiverTypes(c.typeTable).mapTo(contextReceivers, ::loadContextReceiver)
         }.apply {
-            initializer?.replaceTypeRef(returnTypeRef)
+            initializer?.replaceConeTypeOrNull(returnTypeRef.type)
             this.versionRequirements = versionRequirements
             replaceDeprecationsProvider(getDeprecationsProvider(c.session))
             setLazyPublishedVisibility(c.session)
@@ -696,6 +697,6 @@ class FirMemberDeserializer(private val c: FirDeserializationContext) {
         }.toList()
     }
 
-    private fun ProtoBuf.Type.toTypeRef(context: FirDeserializationContext): FirTypeRef =
+    private fun ProtoBuf.Type.toTypeRef(context: FirDeserializationContext): FirResolvedTypeRef =
         context.typeDeserializer.typeRef(this)
 }

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

@@ -108,7 +108,7 @@ class FirTypeDeserializer(
         }
     }
 
-    fun typeRef(proto: ProtoBuf.Type): FirTypeRef {
+    fun typeRef(proto: ProtoBuf.Type): FirResolvedTypeRef {
         return buildResolvedTypeRef {
             annotations += annotationDeserializer.loadTypeAnnotations(proto, nameResolver)
             type = type(proto, annotations.computeTypeAttributes(moduleData.session, shouldExpandTypeAliases = false))
@@ -288,4 +288,4 @@ class FirTypeDeserializer(
         val coneType = type(type)
         return coneType.toTypeProjection(variance)
     }
-}
+}

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt

@@ -1098,7 +1098,7 @@ class Fir2IrVisitor(
             source = elvisExpression.source
             moduleData = session.moduleData
             origin = FirDeclarationOrigin.Source
-            returnTypeRef = elvisExpression.lhs.typeRef
+            returnTypeRef = elvisExpression.lhs.coneType.toFirResolvedTypeRef()
             name = Name.special("<elvis>")
             initializer = elvisExpression.lhs
             symbol = FirPropertySymbol(name)
@@ -1511,7 +1511,7 @@ class Fir2IrVisitor(
     private fun convertToArrayLiteral(arrayLiteral: FirArrayLiteral): IrVararg {
         return arrayLiteral.convertWithOffsets { startOffset, endOffset ->
             val arrayType = arrayLiteral.coneType.toIrType()
-            val elementType = if (arrayLiteral.typeRef is FirResolvedTypeRef) {
+            val elementType = if (arrayLiteral.coneTypeOrNull != null) {
                 arrayType.getArrayElementType(irBuiltIns)
             } else {
                 createErrorType()

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

@@ -551,7 +551,7 @@ internal class AdapterGenerator(
 
     private fun needSamConversion(argument: FirExpression, parameter: FirValueParameter): Boolean {
         // If the type of the argument is already an explicitly subtype of the type of the parameter, we don't need SAM conversion.
-        if (argument.typeRef !is FirResolvedTypeRef ||
+        if (argument.coneTypeOrNull == null ||
             AbstractTypeChecker.isSubtypeOf(
                 session.typeContext.newTypeCheckerState(
                     errorTypesEqualToAnything = false, stubTypesEqualToAnything = true

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

@@ -123,9 +123,7 @@ private fun <T> List<T>.createArrayLiteral(session: FirSession, kind: ConstantVa
                 arguments += element.createConstantOrError(session)
             }
         }
-        typeRef = buildResolvedTypeRef {
-            type = kind.expectedConeType(session).createArrayType()
-        }
+        coneTypeOrNull = kind.expectedConeType(session).createArrayType()
     }
 }
 

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/deserialization/AnnotationsLoader.kt

@@ -42,9 +42,7 @@ internal class AnnotationsLoader(private val session: FirSession, private val ko
             val resolvedClassTypeRef = classId.toLookupTag().toDefaultResolvedTypeRef()
             return buildClassReferenceExpression {
                 classTypeRef = resolvedClassTypeRef
-                typeRef = buildResolvedTypeRef {
-                    type = StandardClassIds.KClass.constructClassLikeType(arrayOf(resolvedClassTypeRef.type), false)
-                }
+                coneTypeOrNull = StandardClassIds.KClass.constructClassLikeType(arrayOf(resolvedClassTypeRef.type), false)
             }
         }
 
@@ -52,7 +50,7 @@ internal class AnnotationsLoader(private val session: FirSession, private val ko
             visitExpression(name, buildGetClassCall {
                 val argument = value.toFirClassReferenceExpression()
                 argumentList = buildUnaryArgumentList(argument)
-                typeRef = argument.typeRef
+                coneTypeOrNull = argument.coneTypeOrNull
             })
         }
 
@@ -78,7 +76,7 @@ internal class AnnotationsLoader(private val session: FirSession, private val ko
                     elements.add(buildGetClassCall {
                         val argument = value.toFirClassReferenceExpression()
                         argumentList = buildUnaryArgumentList(argument)
-                        typeRef = argument.typeRef
+                        coneTypeOrNull = argument.coneTypeOrNull
                     })
                 }
 
@@ -96,11 +94,9 @@ internal class AnnotationsLoader(private val session: FirSession, private val ko
                 override fun visitEnd() {
                     visitExpression(name, buildArrayLiteral {
                         guessArrayTypeIfNeeded(name, elements)?.let {
-                            typeRef = it
+                            coneTypeOrNull = it.coneTypeOrNull
                         } ?: elements.firstOrNull()?.coneType?.createOutArrayType()?.let {
-                            typeRef = buildResolvedTypeRef {
-                                type = it
-                            }
+                            coneTypeOrNull = it
                         }
                         argumentList = buildArgumentList {
                             arguments += elements

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

@@ -24,8 +24,8 @@ import org.jetbrains.kotlin.fir.declarations.utils.*
 import org.jetbrains.kotlin.fir.expressions.FirAnnotation
 import org.jetbrains.kotlin.fir.expressions.FirConstExpression
 import org.jetbrains.kotlin.fir.expressions.unexpandedClassId
-import org.jetbrains.kotlin.fir.java.*
 import org.jetbrains.kotlin.fir.java.FirJavaTypeConversionMode
+import org.jetbrains.kotlin.fir.java.JavaTypeParameterStack
 import org.jetbrains.kotlin.fir.java.declarations.*
 import org.jetbrains.kotlin.fir.java.resolveIfJavaType
 import org.jetbrains.kotlin.fir.java.symbols.FirJavaOverriddenSyntheticPropertySymbol
@@ -41,7 +41,6 @@ import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
 import org.jetbrains.kotlin.fir.types.impl.ConeClassLikeTypeImpl
 import org.jetbrains.kotlin.fir.types.impl.ConeTypeParameterTypeImpl
 import org.jetbrains.kotlin.fir.types.jvm.FirJavaTypeRef
-import org.jetbrains.kotlin.fir.utils.exceptions.withConeTypeEntry
 import org.jetbrains.kotlin.fir.utils.exceptions.withFirEntry
 import org.jetbrains.kotlin.load.java.AnnotationQualifierApplicabilityType
 import org.jetbrains.kotlin.load.java.FakePureImplementationsProvider
@@ -54,8 +53,8 @@ import org.jetbrains.kotlin.types.AbstractTypeChecker
 import org.jetbrains.kotlin.types.model.KotlinTypeMarker
 import org.jetbrains.kotlin.types.model.TypeParameterMarker
 import org.jetbrains.kotlin.types.model.TypeSystemContext
-import org.jetbrains.kotlin.utils.exceptions.errorWithAttachment
 import org.jetbrains.kotlin.util.PrivateForInline
+import org.jetbrains.kotlin.utils.exceptions.errorWithAttachment
 
 class FirSignatureEnhancement(
     private val owner: FirRegularClass,
@@ -363,7 +362,7 @@ class FirSignatureEnhancement(
             }
         }.apply {
             val newValueParameters = firMethod.valueParameters.zip(enhancedValueParameterTypes) { valueParameter, enhancedReturnType ->
-                valueParameter.defaultValue?.replaceTypeRef(enhancedReturnType)
+                valueParameter.defaultValue?.replaceConeTypeOrNull(enhancedReturnType.coneType)
 
                 buildValueParameter {
                     source = valueParameter.source

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

@@ -90,9 +90,8 @@ internal fun JavaAnnotationArgument.toFirExpression(
         )
         is JavaArrayAnnotationArgument -> buildArrayLiteral {
             val argumentTypeRef = expectedTypeRef?.let {
-                typeRef = if (it is FirJavaTypeRef) buildResolvedTypeRef {
-                    type = it.toConeKotlinTypeProbablyFlexible(session, javaTypeParameterStack)
-                } else it
+                coneTypeOrNull =
+                    if (it is FirJavaTypeRef) it.toConeKotlinTypeProbablyFlexible(session, javaTypeParameterStack) else it.coneType
                 buildResolvedTypeRef {
                     type = it.coneTypeSafe<ConeKotlinType>()?.lowerBoundIfFlexible()?.arrayElementType()
                         ?: ConeErrorType(ConeSimpleDiagnostic("expected type is not array type"))
@@ -111,10 +110,10 @@ internal fun JavaAnnotationArgument.toFirExpression(
             argumentList = buildUnaryArgumentList(
                 buildClassReferenceExpression {
                     classTypeRef = resolvedClassTypeRef
-                    typeRef = resolvedTypeRef
+                    coneTypeOrNull = resolvedTypeRef.coneType
                 }
             )
-            typeRef = resolvedTypeRef
+            coneTypeOrNull = resolvedTypeRef.coneType
         }
         is JavaAnnotationAsAnnotationArgument -> getAnnotation().toFirAnnotationCall(session)
         else -> buildErrorExpression {
@@ -168,13 +167,11 @@ private fun buildEnumCall(session: FirSession, classId: ClassId?, entryName: Nam
                 }
 
         if (classId != null) {
-            this.typeRef = buildResolvedTypeRef {
-                type = ConeClassLikeTypeImpl(
-                    classId.toLookupTag(),
-                    emptyArray(),
-                    isNullable = false
-                )
-            }
+            this.coneTypeOrNull = ConeClassLikeTypeImpl(
+                classId.toLookupTag(),
+                emptyArray(),
+                isNullable = false
+            )
         }
     }
 }
@@ -194,9 +191,7 @@ private fun List<JavaAnnotationArgument>.mapJavaTargetArguments(session: FirSess
             isNullable = false,
             ConeAttributes.Empty
         )
-        typeRef = buildResolvedTypeRef {
-            type = elementConeType
-        }
+        coneTypeOrNull = elementConeType
         varargElementType = buildResolvedTypeRef {
             type = elementConeType.createOutArrayType()
         }

compiler/fir/plugin-utils/src/org/jetbrains/kotlin/fir/plugin/FunctionBuildingContext.kt

@@ -88,7 +88,7 @@ public sealed class FunctionBuildingContext<T : FirFunction>(
             symbol = FirValueParameterSymbol(name)
             if (valueParameter.hasDefaultValue) {
                 // TODO: check how it will actually work in fir2ir
-                defaultValue = buildExpressionStub { typeRef = session.builtinTypes.nothingType }
+                defaultValue = buildExpressionStub { coneTypeOrNull = session.builtinTypes.nothingType.type }
             }
             this.containingFunctionSymbol = containingFunctionSymbol
             isCrossinline = valueParameter.isCrossinline

compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/calls/FirReceivers.kt

@@ -8,7 +8,6 @@ package org.jetbrains.kotlin.fir.resolve.calls
 import org.jetbrains.kotlin.KtFakeSourceElementKind
 import org.jetbrains.kotlin.fakeElement
 import org.jetbrains.kotlin.fir.FirSession
-import org.jetbrains.kotlin.fir.copyWithNewSourceKind
 import org.jetbrains.kotlin.fir.declarations.FirResolvePhase
 import org.jetbrains.kotlin.fir.diagnostics.ConeIntermediateDiagnostic
 import org.jetbrains.kotlin.fir.expressions.FirCheckNotNullCall
@@ -29,8 +28,11 @@ import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirScriptSymbol
-import org.jetbrains.kotlin.fir.types.*
+import org.jetbrains.kotlin.fir.types.ConeErrorType
+import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
+import org.jetbrains.kotlin.fir.types.coneTypeSafe
+import org.jetbrains.kotlin.fir.types.constructType
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.types.SmartcastStability
 
@@ -116,12 +118,12 @@ sealed class ImplicitReceiverValue<S : FirBasedSymbol<*>>(
             buildSmartCastExpression {
                 originalExpression = originalReceiverExpression
                 smartcastType = buildResolvedTypeRef {
-                    source = originalReceiverExpression.typeRef.source?.fakeElement(KtFakeSourceElementKind.SmartCastedTypeRef)
+                    source = originalReceiverExpression.source?.fakeElement(KtFakeSourceElementKind.SmartCastedTypeRef)
                     type = this@ImplicitReceiverValue.type
                 }
-                typesFromSmartCast = listOf(type)
+                typesFromSmartCast = listOf(this@ImplicitReceiverValue.type)
                 smartcastStability = SmartcastStability.STABLE_VALUE
-                typeRef = smartcastType.copyWithNewSourceKind(KtFakeSourceElementKind.ImplicitTypeRef)
+                coneTypeOrNull = this@ImplicitReceiverValue.type
             }
         } else {
             originalReceiverExpression
@@ -195,16 +197,15 @@ private fun receiverExpression(
         boundSymbol = symbol
         this.contextReceiverNumber = contextReceiverNumber
     }
-    val typeRef = type.toFirResolvedTypeRef()
     return when (inaccessibleReceiver) {
         false -> buildThisReceiverExpression {
             this.calleeReference = calleeReference
-            this.typeRef = typeRef
+            this.coneTypeOrNull = type
             isImplicit = true
         }
         true -> buildInaccessibleReceiverExpression {
             this.calleeReference = calleeReference
-            this.typeRef = typeRef
+            this.coneTypeOrNull = type
         }
     }
 }

compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/transformers/PhaseUtils.kt

@@ -15,7 +15,7 @@ import org.jetbrains.kotlin.fir.types.ConeKotlinType
 import org.jetbrains.kotlin.fir.types.FirTypeRef
 import org.jetbrains.kotlin.fir.types.coneTypeSafe
 
-fun ConeKotlinType.ensureResolvedTypeDeclaration(
+fun ConeKotlinType?.ensureResolvedTypeDeclaration(
     useSiteSession: FirSession,
     requiredPhase: FirResolvePhase = FirResolvePhase.DECLARATIONS,
 ) {
@@ -29,5 +29,5 @@ fun FirTypeRef.ensureResolvedTypeDeclaration(
     useSiteSession: FirSession,
     requiredPhase: FirResolvePhase = FirResolvePhase.DECLARATIONS,
 ) {
-    coneTypeSafe<ConeKotlinType>()?.ensureResolvedTypeDeclaration(useSiteSession, requiredPhase)
+    coneTypeSafe<ConeKotlinType>().ensureResolvedTypeDeclaration(useSiteSession, requiredPhase)
 }

compiler/fir/providers/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt

@@ -415,7 +415,6 @@ fun FirTypeRef.withReplacedConeType(
             type = newType
             annotations += this@withReplacedConeType.annotations
             delegatedTypeRef = this@withReplacedConeType.delegatedTypeRef
-            isFromStubType = this@withReplacedConeType.type is ConeStubType
         }
     }
 }

compiler/fir/raw-fir/raw-fir.common/src/org/jetbrains/kotlin/fir/builder/AbstractRawFirBuilder.kt

@@ -25,10 +25,7 @@ import org.jetbrains.kotlin.fir.references.builder.buildImplicitThisReference
 import org.jetbrains.kotlin.fir.references.builder.buildResolvedNamedReference
 import org.jetbrains.kotlin.fir.references.builder.buildSimpleNamedReference
 import org.jetbrains.kotlin.fir.symbols.impl.*
-import org.jetbrains.kotlin.fir.types.ConeClassLikeType
-import org.jetbrains.kotlin.fir.types.FirErrorTypeRef
-import org.jetbrains.kotlin.fir.types.FirResolvedTypeRef
-import org.jetbrains.kotlin.fir.types.FirTypeRef
+import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.builder.buildErrorTypeRef
 import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
 import org.jetbrains.kotlin.fir.types.impl.ConeClassLikeTypeImpl
@@ -1116,13 +1113,13 @@ fun <TBase, TSource : TBase, TParameter : TBase> FirRegularClassBuilder.createDa
     ) =
         buildPropertyAccessExpression {
             this.source = parameterSource
-            typeRef = firPropertyReturnTypeRefWithCorrectSourceKind
+            coneTypeOrNull = firPropertyReturnTypeRefWithCorrectSourceKind.coneTypeOrNull
             this.dispatchReceiver = buildThisReceiverExpression {
                 this.source = parameterSource
                 calleeReference = buildImplicitThisReference {
                     boundSymbol = this@createDataClassCopyFunction.symbol
                 }
-                typeRef = classTypeRefWithCorrectSourceKind
+                coneTypeOrNull = classTypeRefWithCorrectSourceKind.coneTypeOrNull
             }
             calleeReference = buildResolvedNamedReference {
                 this.source = parameterSource

compiler/fir/raw-fir/raw-fir.common/src/org/jetbrains/kotlin/fir/builder/ConversionUtils.kt

@@ -19,7 +19,6 @@ import org.jetbrains.kotlin.fir.contracts.FirLegacyRawContractDescription
 import org.jetbrains.kotlin.fir.contracts.builder.buildLegacyRawContractDescription
 import org.jetbrains.kotlin.fir.declarations.FirCallableDeclaration
 import org.jetbrains.kotlin.fir.declarations.FirDeclarationOrigin
-import org.jetbrains.kotlin.fir.declarations.FirFunction
 import org.jetbrains.kotlin.fir.declarations.FirReceiverParameter
 import org.jetbrains.kotlin.fir.declarations.FirVariable
 import org.jetbrains.kotlin.fir.declarations.builder.*
@@ -42,14 +41,16 @@ import org.jetbrains.kotlin.fir.symbols.impl.FirPropertyAccessorSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirValueParameterSymbol
 import org.jetbrains.kotlin.fir.types.ConeClassLikeType
 import org.jetbrains.kotlin.fir.types.ConeStarProjection
-import org.jetbrains.kotlin.fir.types.FirImplicitTypeRef
 import org.jetbrains.kotlin.fir.types.FirTypeRef
 import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
 import org.jetbrains.kotlin.fir.types.builder.buildTypeProjectionWithVariance
-import org.jetbrains.kotlin.fir.types.impl.*
+import org.jetbrains.kotlin.fir.types.constructClassLikeType
+import org.jetbrains.kotlin.fir.types.impl.ConeTypeParameterTypeImpl
+import org.jetbrains.kotlin.fir.types.impl.FirImplicitTypeRefImplWithoutSource
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.name.SpecialNames
+import org.jetbrains.kotlin.name.StandardClassIds
 import org.jetbrains.kotlin.types.ConstantValueKind
 import org.jetbrains.kotlin.types.Variance
 import org.jetbrains.kotlin.types.expressions.OperatorConventions
@@ -351,9 +352,7 @@ fun <T> FirPropertyBuilder.generateAccessorsByDelegate(
                 calleeReference = buildImplicitThisReference {
                     boundSymbol = ownerRegularOrAnonymousObjectSymbol
                 }
-                typeRef = buildResolvedTypeRef {
-                    type = context.dispatchReceiverTypesStack.last()
-                }
+                coneTypeOrNull = context.dispatchReceiverTypesStack.last()
             }
             else -> buildConstExpression(null, ConstantValueKind.Null, null, setType = false)
         }
@@ -376,21 +375,27 @@ fun <T> FirPropertyBuilder.generateAccessorsByDelegate(
             name = this@generateAccessorsByDelegate.name
             resolvedSymbol = this@generateAccessorsByDelegate.symbol
         }
-        typeRef = when {
+        coneTypeOrNull = when {
             !isMember && !isExtension -> if (isVar) {
-                FirImplicitKMutableProperty0TypeRef(null, ConeStarProjection)
+                StandardClassIds.KMutableProperty0.constructClassLikeType(arrayOf(ConeStarProjection))
             } else {
-                FirImplicitKProperty0TypeRef(null, ConeStarProjection)
+                StandardClassIds.KProperty0.constructClassLikeType(arrayOf(ConeStarProjection))
             }
             isMember && isExtension -> if (isVar) {
-                FirImplicitKMutableProperty2TypeRef(null, ConeStarProjection, ConeStarProjection, ConeStarProjection)
+                StandardClassIds.KMutableProperty2.constructClassLikeType(
+                    arrayOf(
+                        ConeStarProjection,
+                        ConeStarProjection,
+                        ConeStarProjection
+                    )
+                )
             } else {
-                FirImplicitKProperty2TypeRef(null, ConeStarProjection, ConeStarProjection, ConeStarProjection)
+                StandardClassIds.KProperty2.constructClassLikeType(arrayOf(ConeStarProjection, ConeStarProjection, ConeStarProjection))
             }
             else -> if (isVar) {
-                FirImplicitKMutableProperty1TypeRef(null, ConeStarProjection, ConeStarProjection)
+                StandardClassIds.KMutableProperty1.constructClassLikeType(arrayOf(ConeStarProjection, ConeStarProjection))
             } else {
-                FirImplicitKProperty1TypeRef(null, ConeStarProjection, ConeStarProjection)
+                StandardClassIds.KProperty1.constructClassLikeType(arrayOf(ConeStarProjection, ConeStarProjection))
             }
         }
         this@generateAccessorsByDelegate.typeParameters.mapTo(typeArguments) {

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

@@ -118,9 +118,9 @@ class FirCallResolver(
             candidate?.updateSourcesOfReceivers()
             functionCall
         }
-        val typeRef = components.typeFromCallee(resultFunctionCall)
-        if (typeRef.type is ConeErrorType) {
-            resultFunctionCall.resultType = typeRef
+        val type = components.typeFromCallee(resultFunctionCall).type
+        if (type is ConeErrorType) {
+            resultFunctionCall.resultType = type
         }
 
         return resultFunctionCall
@@ -344,7 +344,7 @@ class FirCallResolver(
                 return buildResolvedReifiedParameterReference {
                     source = nameReference.source
                     symbol = referencedSymbol
-                    typeRef = typeForReifiedParameterReference(this)
+                    coneTypeOrNull = typeForReifiedParameterReference(this)
                 }
             }
         }

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

@@ -6,6 +6,8 @@
 package org.jetbrains.kotlin.fir
 
 import org.jetbrains.kotlin.KtSourceElement
+import org.jetbrains.kotlin.config.ApiVersion
+import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.declarations.FirClass
 import org.jetbrains.kotlin.fir.declarations.fullyExpandedClass
 import org.jetbrains.kotlin.fir.declarations.getDeprecationForCallSite
@@ -19,8 +21,7 @@ import org.jetbrains.kotlin.fir.resolve.BodyResolveComponents
 import org.jetbrains.kotlin.fir.resolve.calls.getSingleVisibleClassifier
 import org.jetbrains.kotlin.fir.resolve.createCurrentScopeList
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeDeprecated
-import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.resultType
-import org.jetbrains.kotlin.fir.resolve.typeForQualifier
+import org.jetbrains.kotlin.fir.resolve.setTypeOfQualifier
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassLikeSymbol
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
@@ -41,7 +42,7 @@ fun BodyResolveComponents.resolveRootPartOfQualifier(
             this.nonFatalDiagnostics.addAll(nonFatalDiagnosticsFromExpression.orEmpty())
             annotations += qualifiedAccess.annotations
         }.apply {
-            resultType = typeForQualifier(this)
+            setTypeOfQualifier(session)
         }
     }
 
@@ -77,7 +78,7 @@ fun BodyResolveComponents.resolveRootPartOfQualifier(
                 )
                 annotations += qualifiedAccess.annotations
             }.apply {
-                resultType = typeForQualifier(this)
+                setTypeOfQualifier(session)
             }
         }
     }
@@ -126,7 +127,7 @@ fun FirResolvedQualifier.continueQualifier(
                         )
                     )
                 }.apply {
-                    resultType = components.typeForQualifier(this)
+                    setTypeOfQualifier(components.session)
                 }
             }
     }
@@ -154,7 +155,7 @@ private fun FqName.continueQualifierInPackage(
             this.nonFatalDiagnostics.addAll(nonFatalDiagnosticsFromExpression.orEmpty())
             annotations += qualifiedAccess.annotations
         }.apply {
-            resultType = components.typeForQualifier(this)
+            setTypeOfQualifier(components.session)
         }
     }
 
@@ -179,7 +180,7 @@ private fun FqName.continueQualifierInPackage(
         isFullyQualified = true
         annotations += qualifiedAccess.annotations
     }.apply {
-        resultType = components.typeForQualifier(this)
+        setTypeOfQualifier(components.session)
     }
 }
 

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

@@ -65,8 +65,7 @@ fun FirAnonymousFunction.addReturnToLastStatementIfNeeded(session: FirSession) {
     val lastStatement = body.statements.lastOrNull() as? FirExpression ?: return
     if (lastStatement is FirReturnExpression) return
 
-    val returnType = (body.typeRef as? FirResolvedTypeRef) ?: return
-    @OptIn(UnexpandedTypeCheck::class)
+    val returnType = body.coneTypeOrNull ?: return
     if (returnType.isNothing) return
 
     val returnTarget = FirFunctionTarget(null, isLambda = isLambda).also { it.bind(this) }
@@ -212,50 +211,51 @@ fun BodyResolveComponents.buildResolvedQualifierForClass(
         this.nonFatalDiagnostics.addAll(nonFatalDiagnostics)
         this.annotations.addAll(annotations)
     }.build().apply {
-        resultType = if (classId.isLocal) {
-            typeForQualifierByDeclaration(regularClass.fir, resultType, session)
-                ?: session.builtinTypes.unitType
+        if (classId.isLocal) {
+            resultType = typeForQualifierByDeclaration(regularClass.fir, resultType, session)
+                ?.also { replaceCanBeValue(true) }
+                ?: session.builtinTypes.unitType.type
         } else {
-            typeForQualifier(this)
+            setTypeOfQualifier(session)
         }
     }
 }
 
-fun BodyResolveComponents.typeForQualifier(resolvedQualifier: FirResolvedQualifier): FirTypeRef {
-    val classSymbol = resolvedQualifier.symbol
-    val resultType = resolvedQualifier.resultType
+fun FirResolvedQualifier.setTypeOfQualifier(session: FirSession) {
+    val classSymbol = symbol
+    val resultType = resultType
     if (classSymbol != null) {
         classSymbol.lazyResolveToPhase(FirResolvePhase.TYPES)
         val declaration = classSymbol.fir
-        if (declaration !is FirTypeAlias || resolvedQualifier.typeArguments.isEmpty()) {
-            typeForQualifierByDeclaration(declaration, resultType, session)?.let { return it }
+        if (declaration !is FirTypeAlias || typeArguments.isEmpty()) {
+            val typeByDeclaration = typeForQualifierByDeclaration(declaration, resultType, session)
+            if (typeByDeclaration != null) {
+                this.resultType = typeByDeclaration
+                replaceCanBeValue(true)
+                return
+            }
         }
     }
-    return session.builtinTypes.unitType
+    this.resultType = session.builtinTypes.unitType.type
 }
 
-internal fun typeForReifiedParameterReference(parameterReferenceBuilder: FirResolvedReifiedParameterReferenceBuilder): FirTypeRef {
-    val resultType = parameterReferenceBuilder.typeRef
+internal fun typeForReifiedParameterReference(parameterReferenceBuilder: FirResolvedReifiedParameterReferenceBuilder): ConeLookupTagBasedType {
     val typeParameterSymbol = parameterReferenceBuilder.symbol
-    return resultType.resolvedTypeFromPrototype(typeParameterSymbol.constructType(emptyArray(), false))
+    return typeParameterSymbol.constructType(emptyArray(), false)
 }
 
-internal fun typeForQualifierByDeclaration(declaration: FirDeclaration, resultType: FirTypeRef, session: FirSession): FirTypeRef? {
+internal fun typeForQualifierByDeclaration(declaration: FirDeclaration, resultType: ConeKotlinType?, session: FirSession): ConeKotlinType? {
     if (declaration is FirTypeAlias) {
         val expandedDeclaration = declaration.expandedConeType?.lookupTag?.toSymbol(session)?.fir ?: return null
         return typeForQualifierByDeclaration(expandedDeclaration, resultType, session)
     }
     if (declaration is FirRegularClass) {
         if (declaration.classKind == ClassKind.OBJECT) {
-            return resultType.resolvedTypeFromPrototype(
-                declaration.symbol.constructType(emptyArray(), false),
-            )
+            return declaration.symbol.constructType(emptyArray(), false)
         } else {
             val companionObjectSymbol = declaration.companionObjectSymbol
             if (companionObjectSymbol != null) {
-                return resultType.resolvedTypeFromPrototype(
-                    companionObjectSymbol.constructType(emptyArray(), false),
-                )
+                return companionObjectSymbol.constructType(emptyArray(), false)
             }
         }
     }
@@ -395,11 +395,11 @@ private val ConeKotlinType.isKindOfNothing
     get() = lowerBoundIfFlexible().let { it.isNothing || it.isNullableNothing }
 
 private fun FirSmartCastExpressionBuilder.applyResultTypeRef() {
-    typeRef =
+    coneTypeOrNull =
         if (smartcastStability == SmartcastStability.STABLE_VALUE)
-            smartcastType.copyWithNewSourceKind(KtFakeSourceElementKind.ImplicitTypeRef)
+            smartcastType.coneTypeOrNull
         else
-            originalExpression.typeRef.copyWithNewSourceKind(KtFakeSourceElementKind.ImplicitTypeRef)
+            originalExpression.coneTypeOrNull
 }
 
 private fun <T : FirExpression> BodyResolveComponents.transformExpressionUsingSmartcastInfo(
@@ -424,10 +424,8 @@ private fun <T : FirExpression> BodyResolveComponents.transformExpressionUsingSm
     val intersectedType = ConeTypeIntersector.intersectTypes(session.typeContext, allTypes)
     if (intersectedType == originalType && intersectedType !is ConeDynamicType) return null
     val intersectedTypeRef = buildResolvedTypeRef {
-        source = expression.resultType.source?.fakeElement(KtFakeSourceElementKind.SmartCastedTypeRef)
+        source = expression.source?.fakeElement(KtFakeSourceElementKind.SmartCastedTypeRef)
         type = intersectedType
-        annotations += expression.resultType.annotations
-        delegatedTypeRef = expression.resultType
     }
 
     // Example (1): if (x is String) { ... }, where x: dynamic
@@ -443,10 +441,8 @@ private fun <T : FirExpression> BodyResolveComponents.transformExpressionUsingSm
         val reducedTypes = typesFromSmartCast.filterTo(mutableListOf()) { !it.isKindOfNothing }
         val reducedIntersectedType = ConeTypeIntersector.intersectTypes(session.typeContext, reducedTypes)
         val reducedIntersectedTypeRef = buildResolvedTypeRef {
-            source = expression.resultType.source?.fakeElement(KtFakeSourceElementKind.SmartCastedTypeRef)
+            source = expression.source?.fakeElement(KtFakeSourceElementKind.SmartCastedTypeRef)
             type = reducedIntersectedType
-            annotations += expression.resultType.annotations
-            delegatedTypeRef = expression.resultType
         }
         return buildSmartCastExpression {
             originalExpression = expression
@@ -474,17 +470,17 @@ fun FirCheckedSafeCallSubject.propagateTypeFromOriginalReceiver(
 ) {
     // If the receiver expression is smartcast to `null`, it would have `Nothing?` as its type, which may not have members called by user
     // code. Hence, we fallback to the type before intersecting with `Nothing?`.
-    val receiverType = ((nullableReceiverExpression as? FirSmartCastExpression)
+    val receiverType = (nullableReceiverExpression as? FirSmartCastExpression)
         ?.takeIf { it.isStable }
         ?.smartcastTypeWithoutNullableNothing
-        ?: nullableReceiverExpression.typeRef)
-        .coneTypeSafe<ConeKotlinType>() ?: return
+        ?.coneTypeSafe<ConeKotlinType>()
+        ?: nullableReceiverExpression.coneTypeOrNull
+        ?: return
 
     val expandedReceiverType = receiverType.fullyExpandedType(session)
     val updatedReceiverType = expandedReceiverType.makeConeTypeDefinitelyNotNullOrNotNull(session.typeContext).independentInstance()
-    val resolvedTypeRef = typeRef.resolvedTypeFromPrototype(updatedReceiverType)
-    replaceTypeRef(resolvedTypeRef)
-    session.lookupTracker?.recordTypeResolveAsLookup(resolvedTypeRef, source, file.source)
+    replaceConeTypeOrNull(updatedReceiverType)
+    session.lookupTracker?.recordTypeResolveAsLookup(updatedReceiverType, source, file.source)
 }
 
 fun FirSafeCallExpression.propagateTypeFromQualifiedAccessAfterNullCheck(
@@ -505,9 +501,9 @@ fun FirSafeCallExpression.propagateTypeFromQualifiedAccessAfterNullCheck(
         }
     }
 
-    val resolvedTypeRef = typeRef.resolvedTypeFromPrototype(resultingType.independentInstance())
-    replaceTypeRef(resolvedTypeRef)
-    session.lookupTracker?.recordTypeResolveAsLookup(resolvedTypeRef, source, file.source)
+    val independentInstance = resultingType.independentInstance()
+    replaceConeTypeOrNull(independentInstance)
+    session.lookupTracker?.recordTypeResolveAsLookup(independentInstance, source, file.source)
 }
 
 private val FirExpression.isCallToStatementLikeFunction: Boolean

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

@@ -17,14 +17,10 @@ import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.FirNamedArgumentExpression
 import org.jetbrains.kotlin.fir.expressions.FirResolvedQualifier
 import org.jetbrains.kotlin.fir.expressions.builder.buildNamedArgumentExpression
-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.*
 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
 import org.jetbrains.kotlin.fir.scopes.FakeOverrideTypeCalculator
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.types.*
@@ -408,18 +404,18 @@ private fun createFakeArgumentsForReference(
 }
 
 class FirFakeArgumentForCallableReference(
-    val index: Int
+    val index: Int,
 ) : FirExpression() {
     override val source: KtSourceElement?
         get() = null
 
-    override val typeRef: FirTypeRef
+    override val coneTypeOrNull: ConeKotlinType
         get() = shouldNotBeCalled()
 
     override val annotations: List<FirAnnotation>
         get() = shouldNotBeCalled()
 
-    override fun replaceTypeRef(newTypeRef: FirTypeRef) {
+    override fun replaceConeTypeOrNull(newConeTypeOrNull: ConeKotlinType?) {
         shouldNotBeCalled()
     }
 

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

@@ -8,7 +8,8 @@ package org.jetbrains.kotlin.fir.resolve.calls
 import org.jetbrains.kotlin.KtFakeSourceElementKind
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.fakeElement
-import org.jetbrains.kotlin.fir.*
+import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.FirVisibilityChecker
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.utils.getExplicitBackingField
 import org.jetbrains.kotlin.fir.declarations.utils.isStatic
@@ -103,12 +104,12 @@ private fun removeSmartCastTypeForAttemptToFitVisibility(dispatchReceiver: FirEx
                 buildSmartCastExpression {
                     this.originalExpression = originalExpression
                     smartcastType = buildResolvedTypeRef {
-                        source = originalExpression.typeRef.source?.fakeElement(KtFakeSourceElementKind.SmartCastedTypeRef)
+                        source = originalExpression.source?.fakeElement(KtFakeSourceElementKind.SmartCastedTypeRef)
                         type = originalTypeNotNullable
                     }
                     typesFromSmartCast = listOf(originalTypeNotNullable)
                     smartcastStability = expressionWithSmartcastIfStable.smartcastStability
-                    typeRef = smartcastType.copyWithNewSourceKind(KtFakeSourceElementKind.ImplicitTypeRef)
+                    coneTypeOrNull = originalTypeNotNullable
                 }
             else -> originalExpression
         }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/FirInvokeResolveTowerExtension.kt

@@ -310,7 +310,7 @@ private fun BodyResolveComponents.createExplicitReceiverForInvokeByCallable(
             candidate
         )
         dispatchReceiver = candidate.dispatchReceiverExpression()
-        this.typeRef = returnTypeCalculator.tryCalculateReturnType(symbol.fir)
+        coneTypeOrNull = returnTypeCalculator.tryCalculateReturnType(symbol.fir).type
 
         if (!invokeBuiltinExtensionMode) {
             extensionReceiver = extensionReceiverExpression

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/FirTowerResolveTask.kt

@@ -15,14 +15,13 @@ import org.jetbrains.kotlin.fir.expressions.FirQualifiedAccessExpression
 import org.jetbrains.kotlin.fir.expressions.FirResolvedQualifier
 import org.jetbrains.kotlin.fir.expressions.builder.buildExpressionStub
 import org.jetbrains.kotlin.fir.expressions.builder.buildResolvedQualifier
-import org.jetbrains.kotlin.fir.resolve.*
+import org.jetbrains.kotlin.fir.resolve.BodyResolveComponents
+import org.jetbrains.kotlin.fir.resolve.DoubleColonLHS
 import org.jetbrains.kotlin.fir.resolve.calls.*
-import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.resultType
+import org.jetbrains.kotlin.fir.resolve.setTypeOfQualifier
 import org.jetbrains.kotlin.fir.scopes.FirScope
 import org.jetbrains.kotlin.fir.scopes.impl.FirWhenSubjectImportingScope
 import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
-import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
-import org.jetbrains.kotlin.fir.types.impl.FirImplicitBuiltinTypeRef
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.calls.tasks.ExplicitReceiverKind
 import org.jetbrains.kotlin.resolve.descriptorUtil.HIDES_MEMBERS_NAME_LIST
@@ -113,7 +112,7 @@ internal abstract class FirBaseTowerResolveTask(
                 this.symbol = it
                 this.source = source?.fakeElement(KtFakeSourceElementKind.ImplicitReceiver)
             }.apply {
-                resultType = components.typeForQualifier(this)
+                setTypeOfQualifier(components.session)
             }
             ExpressionReceiverValue(resolvedQualifier)
         }
@@ -231,13 +230,10 @@ internal open class FirTowerResolveTask(
         processClassifierScope(info, qualifierReceiver)
 
         if (resolvedQualifier.symbol != null) {
-            val typeRef = resolvedQualifier.typeRef
             if (info.callKind == CallKind.CallableReference && info.lhs is DoubleColonLHS.Type) {
                 val stubReceiver = buildExpressionStub {
                     source = info.explicitReceiver?.source
-                    this.typeRef = buildResolvedTypeRef {
-                        type = info.lhs.type
-                    }
+                    this.coneTypeOrNull = info.lhs.type
                 }
 
                 val stubReceiverInfo = info.replaceExplicitReceiver(stubReceiver)
@@ -245,8 +241,8 @@ internal open class FirTowerResolveTask(
                 runResolverForExpressionReceiver(stubReceiverInfo, stubReceiver, parentGroup = TowerGroup.QualifierValue)
             }
 
-            // NB: yet built-in Unit is used for "no-value" type
-            if (typeRef !is FirImplicitBuiltinTypeRef) {
+            // NB: canBeValue means it's resolved to an object or companion object
+            if (resolvedQualifier.canBeValue) {
                 runResolverForExpressionReceiver(info, resolvedQualifier, parentGroup = TowerGroup.QualifierValue)
             }
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/TowerLevels.kt

@@ -21,7 +21,6 @@ import org.jetbrains.kotlin.fir.expressions.builder.buildResolvedQualifier
 import org.jetbrains.kotlin.fir.resolve.*
 import org.jetbrains.kotlin.fir.resolve.calls.*
 import org.jetbrains.kotlin.fir.resolve.providers.symbolProvider
-import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.resultType
 import org.jetbrains.kotlin.fir.scopes.*
 import org.jetbrains.kotlin.fir.scopes.impl.FirDefaultStarImportingScope
 import org.jetbrains.kotlin.fir.scopes.impl.importedFromObjectOrStaticData
@@ -337,7 +336,7 @@ class ScopeTowerLevel(
             this.symbol = this@toResolvedQualifierExpressionReceiver
             this.source = source?.fakeElement(KtFakeSourceElementKind.ImplicitReceiver)
         }.apply {
-            resultType = bodyResolveComponents.typeForQualifier(this)
+            setTypeOfQualifier(bodyResolveComponents.session)
         }
         return ExpressionReceiverValue(resolvedQualifier)
     }

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

@@ -31,7 +31,10 @@ import org.jetbrains.kotlin.fir.scopes.getFunctions
 import org.jetbrains.kotlin.fir.scopes.impl.toConeType
 import org.jetbrains.kotlin.fir.scopes.unsubstitutedScope
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
-import org.jetbrains.kotlin.fir.symbols.impl.*
+import org.jetbrains.kotlin.fir.symbols.impl.FirClassSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirPropertySymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirTypeParameterSymbol
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.name.StandardClassIds
 import org.jetbrains.kotlin.types.ConstantValueKind
@@ -906,7 +909,7 @@ abstract class FirDataFlowAnalyzer(
     }
 
     fun exitConstExpression(constExpression: FirConstExpression<*>) {
-        if (constExpression.resultType is FirResolvedTypeRef) return
+        if (constExpression.coneTypeOrNull != null) return
         graphBuilder.exitConstExpression(constExpression).mergeIncomingFlow()
     }
 
@@ -1129,7 +1132,7 @@ abstract class FirDataFlowAnalyzer(
             val elvisVariable by lazy { variableStorage.createSynthetic(elvisExpression) }
 
             // If (x ?: null) != null then x != null
-            if (elvisExpression.rhs.resultType.isNullableNothing) {
+            if (elvisExpression.rhs.resultType?.isNullableNothing == true) {
                 val lhsVariable = variableStorage.getOrCreateIfReal(flow, elvisExpression.lhs)
                 if (lhsVariable != null) {
                     flow.addImplication((elvisVariable notEq null) implies (lhsVariable notEq null))
@@ -1137,7 +1140,7 @@ abstract class FirDataFlowAnalyzer(
             }
 
             // If (null ?: x) != null then x != null
-            if (elvisExpression.lhs.resultType.isNullableNothing) {
+            if (elvisExpression.lhs.resultType?.isNullableNothing == true) {
                 val rhsVariable = variableStorage.getOrCreateIfReal(flow, elvisExpression.rhs)
                 if (rhsVariable != null) {
                     flow.addImplication((elvisVariable notEq null) implies (rhsVariable notEq null))

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

@@ -1083,9 +1083,8 @@ 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
+        if (node.fir.resultType?.isNothing != true) return false
         val stub = StubNode(node.owner, node.level)
         val edges = node.followingNodes.map { it to node.edgeTo(it) }
         CFGNode.removeAllOutgoingEdges(node)
@@ -1101,9 +1100,8 @@ class ControlFlowGraphBuilder {
 
     // ----------------------------------- Resolvable call -----------------------------------
 
-    @OptIn(UnexpandedTypeCheck::class)
     fun exitQualifiedAccessExpression(qualifiedAccessExpression: FirQualifiedAccessExpression): QualifiedAccessNode {
-        val returnsNothing = qualifiedAccessExpression.resultType.isNothing
+        val returnsNothing = qualifiedAccessExpression.resultType?.isNothing == true
         val node = createQualifiedAccessNode(qualifiedAccessExpression)
         if (returnsNothing) {
             addNonSuccessfullyTerminatingNode(node)
@@ -1113,9 +1111,8 @@ class ControlFlowGraphBuilder {
         return node
     }
 
-    @OptIn(UnexpandedTypeCheck::class)
     fun exitSmartCastExpression(smartCastExpression: FirSmartCastExpression): SmartCastExpressionExitNode {
-        val returnsNothing = smartCastExpression.resultType.isNothing
+        val returnsNothing = smartCastExpression.resultType?.isNothing == true
         val node = createSmartCastExitNode(smartCastExpression)
         if (returnsNothing) {
             addNonSuccessfullyTerminatingNode(node)
@@ -1147,9 +1144,8 @@ class ControlFlowGraphBuilder {
         return argumentListSplitNodes.pop()?.also { addNewSimpleNode(it) }
     }
 
-    @OptIn(UnexpandedTypeCheck::class)
     fun exitFunctionCall(functionCall: FirFunctionCall, callCompleted: Boolean): FunctionCallNode {
-        val returnsNothing = functionCall.resultType.isNothing
+        val returnsNothing = functionCall.resultType?.isNothing == true
         val node = createFunctionCallNode(functionCall)
         unifyDataFlowFromPostponedLambdas(node, callCompleted)
         if (returnsNothing) {
@@ -1193,11 +1189,10 @@ 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)
-        if (checkNotNullCall.resultType.isNothing) {
+        if (checkNotNullCall.resultType?.isNothing == true) {
             addNonSuccessfullyTerminatingNode(node)
         } else {
             addNewSimpleNode(node)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirBuilderInferenceSession.kt

@@ -11,7 +11,6 @@ import org.jetbrains.kotlin.fir.declarations.FirAnonymousFunction
 import org.jetbrains.kotlin.fir.declarations.FirDeclaration
 import org.jetbrains.kotlin.fir.declarations.hasAnnotation
 import org.jetbrains.kotlin.fir.expressions.*
-import org.jetbrains.kotlin.fir.render
 import org.jetbrains.kotlin.fir.resolve.calls.Candidate
 import org.jetbrains.kotlin.fir.resolve.calls.ImplicitExtensionReceiverValue
 import org.jetbrains.kotlin.fir.resolve.calls.ResolutionContext
@@ -19,7 +18,6 @@ import org.jetbrains.kotlin.fir.resolve.calls.candidate
 import org.jetbrains.kotlin.fir.resolve.substitution.ChainedSubstitutor
 import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutor
 import org.jetbrains.kotlin.fir.resolve.substitution.replaceStubsAndTypeVariablesToErrors
-import org.jetbrains.kotlin.fir.resolve.transformers.FirCallCompletionResultsWriterTransformer
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.visitors.FirDefaultTransformer
 import org.jetbrains.kotlin.fir.visitors.transformSingle
@@ -27,7 +25,9 @@ import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemBuilder
 import org.jetbrains.kotlin.resolve.calls.inference.buildAbstractResultingSubstitutor
 import org.jetbrains.kotlin.resolve.calls.inference.components.ConstraintSystemCompletionMode
-import org.jetbrains.kotlin.resolve.calls.inference.model.*
+import org.jetbrains.kotlin.resolve.calls.inference.model.BuilderInferencePosition
+import org.jetbrains.kotlin.resolve.calls.inference.model.ConstraintStorage
+import org.jetbrains.kotlin.resolve.calls.inference.model.NewConstraintSystemImpl
 import org.jetbrains.kotlin.resolve.calls.inference.registerTypeVariableIfNotPresent
 import org.jetbrains.kotlin.resolve.descriptorUtil.BUILDER_INFERENCE_ANNOTATION_FQ_NAME
 import org.jetbrains.kotlin.types.model.TypeConstructorMarker
@@ -268,10 +268,27 @@ class FirStubTypeTransformer(private val substitutor: ConeSubstitutor) : FirDefa
         if (element is FirResolvable) {
             element.candidate()?.let { processCandidate(it) }
         }
+
+        // Since FirExpressions don't have typeRefs, they need to be updated separately.
+        // FirAnonymousFunctionExpression doesn't support replacing the type
+        // since it delegates the getter to the underlying FirAnonymousFunction.
+        if (element is FirExpression && element !is FirAnonymousFunctionExpression) {
+            element.coneTypeOrNull
+                ?.let(substitutor::substituteOrNull)
+                ?.let { element.replaceConeTypeOrNull(it) }
+        }
+
         @Suppress("UNCHECKED_CAST")
         return element.transformChildren(this, data = null) as E
     }
 
+    override fun transformTypeOperatorCall(typeOperatorCall: FirTypeOperatorCall, data: Nothing?): FirStatement {
+        if (typeOperatorCall.argument.coneTypeOrNull is ConeStubType) {
+            typeOperatorCall.replaceArgFromStubType(true)
+        }
+        return super.transformTypeOperatorCall(typeOperatorCall, data)
+    }
+
     override fun transformResolvedTypeRef(resolvedTypeRef: FirResolvedTypeRef, data: Nothing?): FirTypeRef =
         substitutor.substituteOrNull(resolvedTypeRef.type)?.let {
             resolvedTypeRef.withReplacedConeType(it)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirCallCompleter.kt

@@ -64,9 +64,8 @@ class FirCallCompleter(
         val initialType = typeRef.initialTypeOfCandidate(candidate)
 
         if (call is FirExpression) {
-            val resolvedTypeRef = typeRef.resolvedTypeFromPrototype(initialType)
-            call.resultType = resolvedTypeRef
-            session.lookupTracker?.recordTypeResolveAsLookup(resolvedTypeRef, call.source, components.context.file.source)
+            call.resultType = initialType
+            session.lookupTracker?.recordTypeResolveAsLookup(initialType, call.source, components.context.file.source)
         }
 
         addConstraintFromExpectedType(

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/PostponedArgumentsAnalyzer.kt

@@ -17,8 +17,6 @@ import org.jetbrains.kotlin.fir.resolve.shouldReturnUnit
 import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutor
 import org.jetbrains.kotlin.fir.resolvedTypeFromPrototype
 import org.jetbrains.kotlin.fir.types.*
-import org.jetbrains.kotlin.fir.types.builder.buildErrorTypeRef
-import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
 import org.jetbrains.kotlin.resolve.calls.components.PostponedArgumentsAnalyzerContext
 import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemBuilder
 import org.jetbrains.kotlin.resolve.calls.inference.components.ConstraintSystemCompletionMode
@@ -84,20 +82,14 @@ class PostponedArgumentsAnalyzer(
         callableReferenceAccess.apply {
             replaceCalleeReference(namedReference)
             val typeForCallableReference = atom.resultingTypeForCallableReference
-            val resolvedTypeRef = when {
-                typeForCallableReference != null -> buildResolvedTypeRef {
-                    type = typeForCallableReference
-                }
-                namedReference is FirErrorReferenceWithCandidate -> buildErrorTypeRef {
-                    diagnostic = namedReference.diagnostic
-                }
-                else -> buildErrorTypeRef {
-                    diagnostic = ConeUnresolvedReferenceError(callableReferenceAccess.calleeReference.name)
-                }
+            val resolvedType = when {
+                typeForCallableReference != null -> typeForCallableReference
+                namedReference is FirErrorReferenceWithCandidate -> ConeErrorType(namedReference.diagnostic)
+                else -> ConeErrorType(ConeUnresolvedReferenceError(callableReferenceAccess.calleeReference.name))
             }
-            replaceTypeRef(resolvedTypeRef)
+            replaceConeTypeOrNull(resolvedType)
             resolutionContext.session.lookupTracker?.recordTypeResolveAsLookup(
-                resolvedTypeRef, source, resolutionContext.bodyResolveComponents.file.source
+                resolvedType, source, resolutionContext.bodyResolveComponents.file.source
             )
         }
     }

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

@@ -5,9 +5,7 @@
 
 package org.jetbrains.kotlin.fir.resolve.transformers
 
-import org.jetbrains.kotlin.KtFakeSourceElementKind
 import org.jetbrains.kotlin.builtins.functions.FunctionTypeKind
-import org.jetbrains.kotlin.fakeElement
 import org.jetbrains.kotlin.fir.*
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.utils.isInline
@@ -40,7 +38,6 @@ import org.jetbrains.kotlin.fir.symbols.impl.FirNamedFunctionSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirPropertySymbol
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.builder.buildErrorTypeRef
-import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
 import org.jetbrains.kotlin.fir.types.builder.buildStarProjection
 import org.jetbrains.kotlin.fir.types.builder.buildTypeProjectionWithVariance
 import org.jetbrains.kotlin.fir.types.impl.ConeTypeParameterTypeImpl
@@ -102,20 +99,12 @@ class FirCallCompletionResultsWriterTransformer(
         val subCandidate = calleeReference.candidate
         val declaration = subCandidate.symbol.fir
         val typeArguments = computeTypeArguments(qualifiedAccessExpression, subCandidate)
-        val typeRef = if (declaration is FirCallableDeclaration) {
+        val type = if (declaration is FirCallableDeclaration) {
             val calculated = typeCalculator.tryCalculateReturnType(declaration)
             if (calculated !is FirErrorTypeRef) {
-                buildResolvedTypeRef {
-                    source = calculated.source?.fakeElement(KtFakeSourceElementKind.ImplicitTypeRef)
-                    annotations += calculated.annotations
-                    type = calculated.type
-                }
+                calculated.type
             } else {
-                buildErrorTypeRef {
-                    source = calculated.source?.fakeElement(KtFakeSourceElementKind.ImplicitTypeRef)
-                    type = calculated.type
-                    diagnostic = calculated.diagnostic
-                }
+                ConeErrorType(calculated.diagnostic)
             }
         } else {
             // this branch is for cases when we have
@@ -123,14 +112,12 @@ class FirCallCompletionResultsWriterTransformer(
             // e.g. `T::toString` where T is a generic type.
             // in these cases we should report an error on
             // the calleeReference.source which is not a fake source.
-            buildErrorTypeRef {
-                source = calleeReference.source?.fakeElement(KtFakeSourceElementKind.ImplicitTypeRef)
-                diagnostic =
-                    when (declaration) {
-                        is FirTypeParameter -> ConeTypeParameterInQualifiedAccess(declaration.symbol)
-                        else -> ConeSimpleDiagnostic("Callee reference to candidate without return type: ${declaration.render()}")
-                    }
-            }
+            ConeErrorType(
+                when (declaration) {
+                    is FirTypeParameter -> ConeTypeParameterInQualifiedAccess(declaration.symbol)
+                    else -> ConeSimpleDiagnostic("Callee reference to candidate without return type: ${declaration.render()}")
+                }
+            )
         }
 
         var dispatchReceiver = subCandidate.dispatchReceiverExpression()
@@ -159,12 +146,12 @@ class FirCallCompletionResultsWriterTransformer(
             qualifiedAccessExpression.replaceNonFatalDiagnostics(nonFatalDiagnostics)
         }
 
-        qualifiedAccessExpression.replaceTypeRef(typeRef)
+        qualifiedAccessExpression.replaceConeTypeOrNull(type)
 
         if (declaration !is FirErrorFunction) {
             qualifiedAccessExpression.replaceTypeArguments(typeArguments)
         }
-        session.lookupTracker?.recordTypeResolveAsLookup(typeRef, qualifiedAccessExpression.source, context.file.source)
+        session.lookupTracker?.recordTypeResolveAsLookup(type, qualifiedAccessExpression.source, context.file.source)
         return qualifiedAccessExpression
     }
 
@@ -181,12 +168,11 @@ class FirCallCompletionResultsWriterTransformer(
                 qualifiedAccessExpression
             }
         val result = prepareQualifiedTransform(qualifiedAccessExpression, calleeReference)
-        val typeRef = result.typeRef as FirResolvedTypeRef
         val subCandidate = calleeReference.candidate
 
-        val resultType = typeRef.substituteTypeRef(subCandidate)
+        val resultType = result.coneTypeOrNull?.substituteType(subCandidate)
         resultType.ensureResolvedTypeDeclaration(session)
-        result.replaceTypeRef(resultType)
+        result.replaceConeTypeOrNull(resultType)
         session.lookupTracker?.recordTypeResolveAsLookup(resultType, qualifiedAccessExpression.source, context.file.source)
 
         if (mode == Mode.DelegatedPropertyCompletion) {
@@ -208,10 +194,8 @@ class FirCallCompletionResultsWriterTransformer(
         val calleeReference = functionCall.calleeReference as? FirNamedReferenceWithCandidate
             ?: return functionCall
         val result = prepareQualifiedTransform(functionCall, calleeReference)
-        val typeRef = result.typeRef as FirResolvedTypeRef
         val subCandidate = calleeReference.candidate
-        val resultType: FirTypeRef
-        resultType = typeRef.substituteTypeRef(subCandidate)
+        val resultType = result.coneType.substituteType(subCandidate)
         if (calleeReference.isError) {
             subCandidate.argumentMapping?.let {
                 result.replaceArgumentList(buildArgumentListForErrorCall(result.argumentList, it))
@@ -238,7 +222,7 @@ class FirCallCompletionResultsWriterTransformer(
         }
         val expectedArgumentsTypeMapping = runIf(!calleeReference.isError) { subCandidate.createArgumentsMapping() }
         result.argumentList.transformArguments(this, expectedArgumentsTypeMapping)
-        result.replaceTypeRef(resultType)
+        result.replaceConeTypeOrNull(resultType)
         session.lookupTracker?.recordTypeResolveAsLookup(resultType, functionCall.source, context.file.source)
 
         if (mode == Mode.DelegatedPropertyCompletion) {
@@ -308,19 +292,19 @@ class FirCallCompletionResultsWriterTransformer(
         }
     }
 
-    private fun <D : FirExpression> D.replaceTypeRefWithSubstituted(
+    private fun <D : FirExpression> D.replaceTypeWithSubstituted(
         calleeReference: FirNamedReferenceWithCandidate,
         typeRef: FirResolvedTypeRef,
     ): D {
-        val resultTypeRef = typeRef.substituteTypeRef(calleeReference.candidate)
-        replaceTypeRef(resultTypeRef)
-        session.lookupTracker?.recordTypeResolveAsLookup(resultTypeRef, source, context.file.source)
+        val resultType = typeRef.type.substituteType(calleeReference.candidate)
+        replaceConeTypeOrNull(resultType)
+        session.lookupTracker?.recordTypeResolveAsLookup(resultType, source, context.file.source)
         return this
     }
 
-    private fun FirResolvedTypeRef.substituteTypeRef(
+    private fun ConeKotlinType.substituteType(
         candidate: Candidate,
-    ): FirResolvedTypeRef {
+    ): ConeKotlinType {
         val initialType = candidate.substitutor.substituteOrSelf(type)
         val substitutedType = finallySubstituteOrNull(initialType)
         val finalType = typeApproximator.approximateToSuperType(
@@ -332,9 +316,7 @@ class FirCallCompletionResultsWriterTransformer(
         //
         // In FE1.0, it's not necessary since the annotation for elvis have some strange form (see org.jetbrains.kotlin.resolve.descriptorUtil.AnnotationsWithOnly)
         // that is not propagated further.
-        val withRemovedExactAttribute = finalType?.removeExactAttribute()
-
-        return withReplacedConeType(withRemovedExactAttribute)
+        return finalType?.removeExactAttribute() ?: this
     }
 
     private fun ConeKotlinType.removeExactAttribute(): ConeKotlinType {
@@ -370,15 +352,16 @@ class FirCallCompletionResultsWriterTransformer(
         val subCandidate = calleeReference.candidate
         val typeArguments = computeTypeArguments(callableReferenceAccess, subCandidate)
 
-        val typeRef = callableReferenceAccess.typeRef as FirResolvedTypeRef
-
-        val initialType = calleeReference.candidate.substitutor.substituteOrSelf(typeRef.type)
+        val initialType = calleeReference.candidate.substitutor.substituteOrSelf(callableReferenceAccess.coneType)
         val finalType = finallySubstituteOrSelf(initialType)
 
-        val resultType = typeRef.withReplacedConeType(finalType)
-        callableReferenceAccess.replaceTypeRef(resultType)
+        callableReferenceAccess.replaceConeTypeOrNull(finalType)
         callableReferenceAccess.replaceTypeArguments(typeArguments)
-        session.lookupTracker?.recordTypeResolveAsLookup(resultType, typeRef.source ?: callableReferenceAccess.source, context.file.source)
+        session.lookupTracker?.recordTypeResolveAsLookup(
+            finalType,
+            callableReferenceAccess.source ?: callableReferenceAccess.source,
+            context.file.source
+        )
 
         val resolvedReference = when (calleeReference) {
             is FirErrorReferenceWithCandidate -> calleeReference.toErrorReference(calleeReference.diagnostic)
@@ -413,9 +396,8 @@ class FirCallCompletionResultsWriterTransformer(
         ): FirStatement {
             val originalType = qualifiedAccessExpression.coneType
             val substitutedReceiverType = finallySubstituteOrNull(originalType) ?: return qualifiedAccessExpression
-            val resolvedTypeRef = qualifiedAccessExpression.typeRef.resolvedTypeFromPrototype(substitutedReceiverType)
-            qualifiedAccessExpression.replaceTypeRef(resolvedTypeRef)
-            session.lookupTracker?.recordTypeResolveAsLookup(resolvedTypeRef, qualifiedAccessExpression.source, context.file.source)
+            qualifiedAccessExpression.replaceConeTypeOrNull(substitutedReceiverType)
+            session.lookupTracker?.recordTypeResolveAsLookup(substitutedReceiverType, qualifiedAccessExpression.source, context.file.source)
             return qualifiedAccessExpression
         }
 
@@ -651,16 +633,15 @@ class FirCallCompletionResultsWriterTransformer(
     override fun transformBlock(block: FirBlock, data: ExpectedArgumentType?): FirStatement {
         val initialType = block.coneTypeSafe<ConeKotlinType>()
         if (initialType != null) {
-            val finalType = finallySubstituteOrNull(initialType)
-            var resultType = block.resultType.withReplacedConeType(finalType)
-            resultType.coneTypeSafe<ConeIntegerLiteralType>()?.let {
-                resultType = resultType.resolvedTypeFromPrototype(it.getApproximatedType(data?.getExpectedType(block)?.fullyExpandedType(session)))
+            var resultType = finallySubstituteOrNull(initialType) ?: block.resultType
+            (resultType as? ConeIntegerLiteralType)?.let {
+                resultType = it.getApproximatedType(data?.getExpectedType(block)?.fullyExpandedType(session))
             }
-            block.replaceTypeRef(resultType)
+            block.replaceConeTypeOrNull(resultType)
             session.lookupTracker?.recordTypeResolveAsLookup(resultType, block.source, context.file.source)
         }
         transformElement(block, data)
-        if (block.resultType is FirErrorTypeRef) {
+        if (block.resultType is ConeErrorType) {
             block.writeResultType(session)
         }
         return block
@@ -709,7 +690,7 @@ class FirCallCompletionResultsWriterTransformer(
         }
 
         val typeRef = typeCalculator.tryCalculateReturnType(declaration)
-        syntheticCall.replaceTypeRefWithSubstituted(calleeReference, typeRef)
+        syntheticCall.replaceTypeWithSubstituted(calleeReference, typeRef)
         transformSyntheticCallChildren(syntheticCall, data)
 
         return syntheticCall.apply {
@@ -761,7 +742,7 @@ class FirCallCompletionResultsWriterTransformer(
     }
 
     override fun transformArrayLiteral(arrayLiteral: FirArrayLiteral, data: ExpectedArgumentType?): FirStatement {
-        if (arrayLiteral.typeRef !is FirImplicitTypeRef) return arrayLiteral
+        if (arrayLiteral.coneTypeOrNull != null) return arrayLiteral
         val expectedArrayType = data?.getExpectedType(arrayLiteral)
         val expectedArrayElementType = expectedArrayType?.arrayElementType()
         arrayLiteral.transformChildren(this, expectedArrayElementType?.toExpectedType())
@@ -770,9 +751,8 @@ class FirCallCompletionResultsWriterTransformer(
                 typeApproximator.approximateToSuperType(it, TypeApproximatorConfiguration.FinalApproximationAfterResolutionAndInference)
                     ?: it
             } ?: expectedArrayElementType ?: session.builtinTypes.nullableAnyType.type
-        arrayLiteral.resultType = arrayLiteral.typeRef.resolvedTypeFromPrototype(
+        arrayLiteral.resultType =
             arrayElementType.createArrayType(createPrimitiveArrayTypeIfPossible = expectedArrayType?.isPrimitiveArray == true)
-        )
         return arrayLiteral
     }
 

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

@@ -7,7 +7,7 @@ package org.jetbrains.kotlin.fir.resolve.transformers
 
 import org.jetbrains.kotlin.KtFakeSourceElementKind
 import org.jetbrains.kotlin.fakeElement
-import org.jetbrains.kotlin.fir.*
+import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.declarations.FirFile
 import org.jetbrains.kotlin.fir.declarations.FirResolvePhase
 import org.jetbrains.kotlin.fir.declarations.FirValueParameter
@@ -15,6 +15,9 @@ import org.jetbrains.kotlin.fir.diagnostics.ConeDiagnostic
 import org.jetbrains.kotlin.fir.diagnostics.ConeSimpleDiagnostic
 import org.jetbrains.kotlin.fir.diagnostics.ConeUnexpectedTypeArgumentsError
 import org.jetbrains.kotlin.fir.expressions.FirStatement
+import org.jetbrains.kotlin.fir.lookupTracker
+import org.jetbrains.kotlin.fir.recordTypeLookup
+import org.jetbrains.kotlin.fir.render
 import org.jetbrains.kotlin.fir.resolve.FirTypeResolutionResult
 import org.jetbrains.kotlin.fir.resolve.SupertypeSupplier
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeUnsupportedDefaultValueInFunctionType
@@ -238,9 +241,7 @@ class FirSpecificTypeResolverTransformer(
     override fun transformValueParameter(valueParameter: FirValueParameter, data: ScopeClassDeclaration): FirStatement {
         val result = transformElement(valueParameter, data)
         result.defaultValue?.let {
-            it.resultType = buildErrorTypeRef {
-                diagnostic = ConeUnsupportedDefaultValueInFunctionType(it.source)
-            }
+            it.resultType = ConeErrorType(ConeUnsupportedDefaultValueInFunctionType(it.source))
         }
         return result
     }

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

@@ -192,7 +192,7 @@ class FirSyntheticCallGenerator(
             source = arrayLiteral.source
         }.also {
             if (arrayOfSymbol == null) {
-                it.resultType = components.typeFromCallee(it)
+                it.resultType = components.typeFromCallee(it).type
             }
         }
     }
@@ -242,7 +242,7 @@ class FirSyntheticCallGenerator(
             // If the callable reference cannot be resolved with the expected type, let's try to resolve it with any type and report
             // something like INITIALIZER_TYPE_MISMATCH or NONE_APPLICABLE instead of UNRESOLVED_REFERENCE.
 
-            check(callableReferenceAccess.calleeReference is FirSimpleNamedReference && callableReferenceAccess.typeRef is FirImplicitTypeRef) {
+            check(callableReferenceAccess.calleeReference is FirSimpleNamedReference && callableReferenceAccess.coneTypeOrNull == null) {
                 "Expected FirCallableReferenceAccess to be unresolved."
             }
 

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

@@ -9,12 +9,18 @@ import org.jetbrains.kotlin.contracts.description.LogicOperationKind
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.diagnostics.WhenMissingCase
-import org.jetbrains.kotlin.fir.*
-import org.jetbrains.kotlin.fir.declarations.*
+import org.jetbrains.kotlin.fir.FirElement
+import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.declarations.FirEnumEntry
+import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.collectEnumEntries
+import org.jetbrains.kotlin.fir.declarations.getSealedClassInheritors
 import org.jetbrains.kotlin.fir.declarations.utils.isExpect
 import org.jetbrains.kotlin.fir.declarations.utils.modality
+import org.jetbrains.kotlin.fir.enumWhenTracker
 import org.jetbrains.kotlin.fir.expressions.*
 import org.jetbrains.kotlin.fir.expressions.impl.FirElseIfTrueCondition
+import org.jetbrains.kotlin.fir.reportEnumUsageInWhen
 import org.jetbrains.kotlin.fir.resolve.BodyResolveComponents
 import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.resolve.providers.symbolProvider
@@ -217,8 +223,7 @@ 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) {
+            if (argument.coneTypeOrNull?.isNullableNothing == true) {
                 data.containsNull = true
             }
         }

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

@@ -22,7 +22,6 @@ import org.jetbrains.kotlin.fir.resolve.ScopeSession
 import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.resolve.scope
 import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.resultType
-import org.jetbrains.kotlin.fir.resolvedTypeFromPrototype
 import org.jetbrains.kotlin.fir.scopes.FakeOverrideTypeCalculator
 import org.jetbrains.kotlin.fir.scopes.getFunctions
 import org.jetbrains.kotlin.fir.scopes.impl.originalForWrappedIntegerOperator
@@ -64,7 +63,7 @@ class IntegerLiteralAndOperatorApproximationTransformer(
     ): FirStatement {
         val type = constExpression.coneTypeSafe<ConeIntegerLiteralType>() ?: return constExpression
         val approximatedType = type.getApproximatedType(data?.fullyExpandedType(session))
-        constExpression.resultType = constExpression.resultType.resolvedTypeFromPrototype(approximatedType)
+        constExpression.resultType = approximatedType
         @Suppress("UNCHECKED_CAST")
         val kind = approximatedType.toConstKind() as ConstantValueKind<T>
         constExpression.replaceKind(kind)
@@ -83,7 +82,7 @@ class IntegerLiteralAndOperatorApproximationTransformer(
         call.transformExtensionReceiver(this, null)
         call.argumentList.transformArguments(this, null)
 
-        call.resultType = call.resultType.resolvedTypeFromPrototype(approximatedType)
+        call.resultType = approximatedType
 
         val calleeReference = call.calleeReference
         // callee reference may also be an error reference and it's ok if wrapped operator function leaks throw it
@@ -110,15 +109,15 @@ class IntegerLiteralAndOperatorApproximationTransformer(
 
         if (approximatedType.isInt || approximatedType.isUInt) return call
         val typeBeforeConversion = if (operatorType.isUnsigned) {
-            session.builtinTypes.uIntType
+            session.builtinTypes.uIntType.type
         } else {
-            session.builtinTypes.intType
+            session.builtinTypes.intType.type
         }
-        call.replaceTypeRef(typeBeforeConversion)
+        call.replaceConeTypeOrNull(typeBeforeConversion)
 
         return buildFunctionCall {
             source = call.source?.fakeElement(KtFakeSourceElementKind.IntToLongConversion)
-            typeRef = session.builtinTypes.longType
+            coneTypeOrNull = session.builtinTypes.longType.type
             explicitReceiver = call
             dispatchReceiver = call
             this.calleeReference = buildResolvedNamedReference {

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

@@ -5,8 +5,10 @@
 
 package org.jetbrains.kotlin.fir.resolve.transformers.body.resolve
 
-import org.jetbrains.kotlin.*
-import org.jetbrains.kotlin.fir.*
+import org.jetbrains.kotlin.KtFakeSourceElementKind
+import org.jetbrains.kotlin.KtSourceElement
+import org.jetbrains.kotlin.fakeElement
+import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.declarations.FirValueParameter
 import org.jetbrains.kotlin.fir.diagnostics.ConeSimpleDiagnostic
 import org.jetbrains.kotlin.fir.diagnostics.DiagnosticKind
@@ -16,15 +18,14 @@ import org.jetbrains.kotlin.fir.expressions.FirNamedArgumentExpression
 import org.jetbrains.kotlin.fir.expressions.builder.buildVarargArgumentsExpression
 import org.jetbrains.kotlin.fir.resolve.providers.symbolProvider
 import org.jetbrains.kotlin.fir.types.*
-import org.jetbrains.kotlin.fir.types.builder.buildErrorTypeRef
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.StandardClassIds
 import org.jetbrains.kotlin.types.ConstantValueKind
 
-internal inline var FirExpression.resultType: FirTypeRef
-    get() = typeRef
+internal inline var FirExpression.resultType: ConeKotlinType?
+    get() = coneTypeOrNull
     set(type) {
-        replaceTypeRef(type)
+        replaceConeTypeOrNull(type)
     }
 
 internal fun remapArgumentsWithVararg(
@@ -43,7 +44,7 @@ internal fun remapArgumentsWithVararg(
     val varargArgument = buildVarargArgumentsExpression {
         // TODO: ideally we should use here a source from the use-site and not from the declaration-site, KT-59682
         this.varargElementType = varargParameterTypeRef.withReplacedConeType(varargElementType, KtFakeSourceElementKind.VarargArgument)
-        this.typeRef = varargParameterTypeRef.withReplacedConeType(varargArrayType, KtFakeSourceElementKind.VarargArgument)
+        this.coneTypeOrNull = varargArrayType
         var startOffset = Int.MAX_VALUE
         var endOffset = 0
         var firstVarargElementSource: KtSourceElement? = null
@@ -87,16 +88,9 @@ fun FirBlock.writeResultType(session: FirSession) {
         else -> null
     }
     resultType = if (resultExpression == null) {
-        resultType.resolvedTypeFromPrototype(session.builtinTypes.unitType.type)
+        session.builtinTypes.unitType.type
     } else {
-        val theType = resultExpression.resultType
-        if (theType is FirResolvedTypeRef) {
-            theType.copyWithNewSourceKind(KtFakeSourceElementKind.ImplicitTypeRef)
-        } else {
-            buildErrorTypeRef {
-                diagnostic = ConeSimpleDiagnostic("No type for block", DiagnosticKind.InferenceError)
-            }
-        }
+        resultExpression.resultType ?: ConeErrorType(ConeSimpleDiagnostic("No type for block", DiagnosticKind.InferenceError))
     }
 }
 

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

@@ -45,7 +45,7 @@ class FirArrayOfCallTransformer : FirDefaultTransformer<FirSession>() {
                     }
                 }
             }
-            typeRef = functionCall.typeRef
+            coneTypeOrNull = functionCall.coneTypeOrNull
         }
 
         val calleeReference = functionCall.calleeReference

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

@@ -10,11 +10,13 @@ import org.jetbrains.kotlin.fir.expressions.*
 import org.jetbrains.kotlin.fir.expressions.impl.FirElseIfTrueCondition
 import org.jetbrains.kotlin.fir.expressions.impl.FirEmptyExpressionBlock
 import org.jetbrains.kotlin.fir.references.FirResolvedNamedReference
-import org.jetbrains.kotlin.fir.resolve.*
+import org.jetbrains.kotlin.fir.resolve.ResolutionMode
 import org.jetbrains.kotlin.fir.resolve.calls.isUnitOrFlexibleUnit
+import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
+import org.jetbrains.kotlin.fir.resolve.transformWhenSubjectExpressionUsingSmartcastInfo
 import org.jetbrains.kotlin.fir.resolve.transformers.FirSyntheticCallGenerator
 import org.jetbrains.kotlin.fir.resolve.transformers.FirWhenExhaustivenessTransformer
-import org.jetbrains.kotlin.fir.resolvedTypeFromPrototype
+import org.jetbrains.kotlin.fir.resolve.withExpectedType
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.visitors.transformSingle
 
@@ -54,7 +56,7 @@ class FirControlFlowStatementsResolveTransformer(transformer: FirAbstractBodyRes
     // ------------------------------- When expressions -------------------------------
 
     override fun transformWhenExpression(whenExpression: FirWhenExpression, data: ResolutionMode): FirStatement {
-        if (whenExpression.calleeReference is FirResolvedNamedReference && whenExpression.resultType !is FirImplicitTypeRef) {
+        if (whenExpression.calleeReference is FirResolvedNamedReference && whenExpression.resultType != null) {
             return whenExpression
         }
         whenExpression.annotations.forEach { it.accept(this, data) }
@@ -114,7 +116,7 @@ class FirControlFlowStatementsResolveTransformer(transformer: FirAbstractBodyRes
 
     private fun FirWhenExpression.replaceReturnTypeIfNotExhaustive(): FirWhenExpression {
         if (!isProperlyExhaustive) {
-            resultType = resultType.resolvedTypeFromPrototype(session.builtinTypes.unitType.type)
+            resultType = session.builtinTypes.unitType.type
         }
         return this
     }
@@ -141,7 +143,7 @@ class FirControlFlowStatementsResolveTransformer(transformer: FirAbstractBodyRes
         data: ResolutionMode
     ): FirStatement {
         val parentWhen = whenSubjectExpression.whenRef.value
-        val subjectType = parentWhen.subject?.resultType ?: parentWhen.subjectVariable?.returnTypeRef
+        val subjectType = parentWhen.subject?.resultType ?: parentWhen.subjectVariable?.returnTypeRef?.coneTypeOrNull
         if (subjectType != null) {
             whenSubjectExpression.resultType = subjectType
         }
@@ -152,7 +154,7 @@ class FirControlFlowStatementsResolveTransformer(transformer: FirAbstractBodyRes
     // ------------------------------- Try/catch expressions -------------------------------
 
     override fun transformTryExpression(tryExpression: FirTryExpression, data: ResolutionMode): FirStatement {
-        if (tryExpression.calleeReference is FirResolvedNamedReference && tryExpression.resultType !is FirImplicitTypeRef) {
+        if (tryExpression.calleeReference is FirResolvedNamedReference && tryExpression.resultType != null) {
             return tryExpression
         }
 
@@ -215,7 +217,6 @@ class FirControlFlowStatementsResolveTransformer(transformer: FirAbstractBodyRes
         data: ResolutionMode,
     ): FirStatement {
         return throwExpression.apply {
-            replaceTypeRef(throwExpression.typeRef.transform(transformer, data))
             transformAnnotations(transformer, data)
             transformException(transformer, withExpectedType(session.builtinTypes.throwableType))
             dataFlowAnalyzer.exitThrowExceptionNode(this)
@@ -268,7 +269,7 @@ class FirControlFlowStatementsResolveTransformer(transformer: FirAbstractBodyRes
                 val newReturnType =
                     lhsType.makeConeTypeDefinitelyNotNullOrNotNull(session.typeContext)
                         .convertToNonRawVersion()
-                result.replaceTypeRef(result.typeRef.resolvedTypeFromPrototype(newReturnType))
+                result.replaceConeTypeOrNull(newReturnType)
                 isLhsNotNull = true
             }
         }
@@ -279,8 +280,8 @@ class FirControlFlowStatementsResolveTransformer(transformer: FirAbstractBodyRes
             ) {
                 // Sometimes return type for special call for elvis operator might be nullable,
                 // but result is not nullable if the right type is not nullable
-                result.replaceTypeRef(
-                    result.typeRef.withReplacedConeType(result.coneType.makeConeTypeDefinitelyNotNullOrNotNull(session.typeContext))
+                result.replaceConeTypeOrNull(
+                    result.coneType.makeConeTypeDefinitelyNotNullOrNotNull(session.typeContext)
                 )
             }
         }

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

@@ -228,29 +228,29 @@ open class FirDeclarationsResolveTransformer(
         //     get() = delegate.getValue(thisRef, kProperty: KProperty0/1/2<..., SomeType>)
         //     set() = delegate.getValue(thisRef, kProperty: KProperty0/1/2<..., SomeType>, value)
         val propertyReferenceAccess = resolvedArgumentMapping?.keys?.toList()?.getOrNull(1) as? FirCallableReferenceAccess ?: return
-        val typeRef = propertyReferenceAccess.typeRef
-        if (typeRef is FirResolvedTypeRef && property.returnTypeRef is FirResolvedTypeRef) {
-            val typeArguments = (typeRef.type as ConeClassLikeType).typeArguments
+        val type = propertyReferenceAccess.coneTypeOrNull
+        if (type != null && property.returnTypeRef is FirResolvedTypeRef) {
+            val typeArguments = (type.type as ConeClassLikeType).typeArguments
             val extensionType = property.receiverParameter?.typeRef?.coneType
             val dispatchType = context.containingClass?.let { containingClass ->
                 containingClass.symbol.constructStarProjectedType(containingClass.typeParameters.size)
             }
-            propertyReferenceAccess.replaceTypeRef(
-                buildResolvedTypeRef {
-                    source = typeRef.source
-                    annotations.addAll(typeRef.annotations)
-                    type = (typeRef.type as ConeClassLikeType).lookupTag.constructClassType(
-                        typeArguments.mapIndexed { index, argument ->
-                            when (index) {
-                                typeArguments.lastIndex -> property.returnTypeRef.coneType
-                                0 -> extensionType ?: dispatchType
-                                else -> dispatchType
-                            } ?: argument
-                        }.toTypedArray(),
-                        isNullable = false
+            propertyReferenceAccess.replaceConeTypeOrNull(
+                (type.type as ConeClassLikeType).lookupTag.constructClassType(
+                    typeArguments.mapIndexed { index, argument ->
+                        when (index) {
+                            typeArguments.lastIndex -> property.returnTypeRef.coneType
+                            0 -> extensionType ?: dispatchType
+                            else -> dispatchType
+                        } ?: argument
+                    }.toTypedArray(),
+                    isNullable = false
+                ).also {
+                    session.lookupTracker?.recordTypeResolveAsLookup(
+                        it,
+                        propertyReferenceAccess.source ?: source,
+                        components.file.source
                     )
-                }.also {
-                    session.lookupTracker?.recordTypeResolveAsLookup(it, propertyReferenceAccess.source ?: source, components.file.source)
                 }
             )
         }
@@ -343,9 +343,9 @@ open class FirDeclarationsResolveTransformer(
                 val substitutor = createTypeSubstitutorByTypeConstructor(
                     typeVariableTypeToStubType, session.typeContext, approximateIntegerLiterals = true
                 )
-                val delegateExpressionTypeRef = delegateExpression.typeRef
-                val stubTypeSubstituted = substitutor.substituteOrNull(delegateExpressionTypeRef.coneType)
-                delegateExpression.replaceTypeRef(delegateExpressionTypeRef.withReplacedConeType(stubTypeSubstituted))
+                val delegateExpressionType = delegateExpression.coneType
+                val stubTypeSubstituted = substitutor.substituteOrNull(delegateExpressionType)
+                delegateExpression.replaceConeTypeOrNull(stubTypeSubstituted)
             }
         }
 
@@ -377,7 +377,7 @@ open class FirDeclarationsResolveTransformer(
                 )
             )
 
-            provideDelegateCall.replaceTypeRef(provideDelegateCall.typeRef.resolvedTypeFromPrototype(stubTypeSubstituted))
+            provideDelegateCall.replaceConeTypeOrNull(stubTypeSubstituted)
             return provideDelegateCall
         }
 
@@ -643,19 +643,19 @@ open class FirDeclarationsResolveTransformer(
         if (result.returnTypeRef is FirImplicitTypeRef) {
             val simpleFunction = function as? FirSimpleFunction
             val returnExpression = (body?.statements?.singleOrNull() as? FirReturnExpression)?.result
-            val returnTypeRef = if (returnExpression?.typeRef is FirResolvedTypeRef) {
-                returnExpression.resultType.approximateDeclarationType(
+            val expressionType = returnExpression?.coneTypeOrNull
+            val returnTypeRef = expressionType
+                ?.toFirResolvedTypeRef(result.returnTypeRef.source)
+                ?.approximateDeclarationType(
                     session,
                     simpleFunction?.visibilityForApproximation(),
                     isLocal = simpleFunction?.isLocal == true,
                     isInlineFunction = simpleFunction?.isInline == true
-                ).copyWithNewSource(result.returnTypeRef.source)
-            } else {
-                buildErrorTypeRef {
+                )
+                ?: buildErrorTypeRef {
                     source = result.returnTypeRef.source
                     diagnostic = ConeSimpleDiagnostic("empty body", DiagnosticKind.Other)
                 }
-            }
             result.transformReturnTypeRef(transformer, withExpectedType(returnTypeRef))
         }
 
@@ -982,7 +982,7 @@ open class FirDeclarationsResolveTransformer(
         val inferredType = if (backingField is FirDefaultPropertyBackingField) {
             propertyType
         } else {
-            backingField.initializer?.unwrapSmartcastExpression()?.typeRef
+            backingField.initializer?.unwrapSmartcastExpression()?.coneTypeOrNull?.toFirResolvedTypeRef()
         }
         val resultType = inferredType
             ?: return backingField.transformReturnTypeRef(
@@ -1011,7 +1011,7 @@ open class FirDeclarationsResolveTransformer(
             val resultType = when {
                 initializer != null -> {
                     val unwrappedInitializer = initializer.unwrapSmartcastExpression()
-                    unwrappedInitializer.resultType
+                    unwrappedInitializer.resultType?.toFirResolvedTypeRef()
                 }
                 variable.getter != null && variable.getter !is FirDefaultPropertyAccessor -> variable.getter?.returnTypeRef
                 else -> null
@@ -1094,10 +1094,10 @@ open class FirDeclarationsResolveTransformer(
     private val FirVariable.initializerResolved: Boolean
         get() {
             val initializer = initializer ?: return false
-            return initializer.typeRef is FirResolvedTypeRef && initializer !is FirErrorExpression
+            return initializer.coneTypeOrNull != null && initializer !is FirErrorExpression
         }
 
     protected val FirFunction.bodyResolved: Boolean
-        get() = body !is FirLazyBlock && body?.typeRef is FirResolvedTypeRef
+        get() = body !is FirLazyBlock && body?.coneTypeOrNull != null
 
 }

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

@@ -37,7 +37,7 @@ import org.jetbrains.kotlin.fir.scopes.impl.isWrappedIntegerOperatorForUnsignedT
 import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.builder.buildErrorTypeRef
-import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
+import org.jetbrains.kotlin.fir.types.impl.FirImplicitTypeRefImplWithoutSource
 import org.jetbrains.kotlin.fir.visitors.FirDefaultTransformer
 import org.jetbrains.kotlin.fir.visitors.FirTransformer
 import org.jetbrains.kotlin.fir.visitors.TransformData
@@ -68,15 +68,13 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
     }
 
     override fun transformExpression(expression: FirExpression, data: ResolutionMode): FirStatement {
-        if (expression.resultType is FirImplicitTypeRef && expression !is FirWrappedExpression) {
-            val type = buildErrorTypeRef {
-                source = expression.source
-                diagnostic = ConeSimpleDiagnostic(
+        if (expression.resultType == null && expression !is FirWrappedExpression) {
+            expression.resultType = ConeErrorType(
+                ConeSimpleDiagnostic(
                     "Type calculating for ${expression::class} is not supported",
                     DiagnosticKind.InferenceError
                 )
-            }
-            expression.resultType = type
+            )
         }
         return (expression.transformChildren(transformer, data) as FirStatement)
     }
@@ -97,7 +95,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
         data: ResolutionMode,
         isUsedAsReceiver: Boolean,
     ): FirStatement {
-        if (qualifiedAccessExpression.typeRef is FirResolvedTypeRef && qualifiedAccessExpression.calleeReference !is FirSimpleNamedReference) {
+        if (qualifiedAccessExpression.coneTypeOrNull != null && qualifiedAccessExpression.calleeReference !is FirSimpleNamedReference) {
             return qualifiedAccessExpression
         }
 
@@ -115,21 +113,16 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
                     }
                 }
                 val implicitType = implicitReceiver?.originalType
-                qualifiedAccessExpression.resultType = when {
-                    implicitReceiver is InaccessibleImplicitReceiverValue -> buildErrorTypeRef {
-                        source = qualifiedAccessExpression.source
-                        diagnostic = ConeInstanceAccessBeforeSuperCall("<this>")
-                    }
-                    implicitType != null -> implicitType.toFirResolvedTypeRef(callee.source?.fakeElement(KtFakeSourceElementKind.ImplicitTypeRef))
-                    labelName != null -> buildErrorTypeRef {
-                        source = qualifiedAccessExpression.source
-                        diagnostic = ConeSimpleDiagnostic("Unresolved this@$labelName", DiagnosticKind.UnresolvedLabel)
-                    }
-                    else -> buildErrorTypeRef {
-                        source = qualifiedAccessExpression.source
-                        diagnostic = ConeSimpleDiagnostic("'this' is not defined in this context", DiagnosticKind.NoThis)
-                    }
+                val resultType: ConeKotlinType = when {
+                    implicitReceiver is InaccessibleImplicitReceiverValue -> ConeErrorType(ConeInstanceAccessBeforeSuperCall("<this>"))
+                    implicitType != null -> implicitType
+                    labelName != null -> ConeErrorType(ConeSimpleDiagnostic("Unresolved this@$labelName", DiagnosticKind.UnresolvedLabel))
+                    else -> ConeErrorType(ConeSimpleDiagnostic("'this' is not defined in this context", DiagnosticKind.NoThis))
                 }
+                (resultType as? ConeErrorType)?.diagnostic?.let {
+                    callee.replaceDiagnostic(it)
+                }
+                qualifiedAccessExpression.resultType = resultType
                 qualifiedAccessExpression
             }
             is FirSuperReference -> {
@@ -141,12 +134,12 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
             }
             is FirDelegateFieldReference -> {
                 val delegateFieldSymbol = callee.resolvedSymbol
-                qualifiedAccessExpression.resultType = delegateFieldSymbol.fir.delegate!!.typeRef
+                qualifiedAccessExpression.resultType = delegateFieldSymbol.fir.delegate!!.coneTypeOrNull
                 qualifiedAccessExpression
             }
             is FirResolvedNamedReference,
             is FirErrorNamedReference -> {
-                if (qualifiedAccessExpression.typeRef !is FirResolvedTypeRef) {
+                if (qualifiedAccessExpression.coneTypeOrNull == null) {
                     storeTypeFromCallee(qualifiedAccessExpression, isLhsOfAssignment = false)
                 }
                 qualifiedAccessExpression
@@ -271,7 +264,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
                 return markSuperReferenceError(diagnostic, superReferenceContainer, superReference)
             }
             superTypeRef is FirResolvedTypeRef -> {
-                superReferenceContainer.resultType = superTypeRef.copyWithNewSourceKind(KtFakeSourceElementKind.SuperCallExplicitType)
+                superReferenceContainer.resultType = superTypeRef.type
             }
             superTypeRef !is FirImplicitTypeRef -> {
                 components.typeResolverTransformer.withBareTypes {
@@ -302,8 +295,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
                     source = superTypeRef.source
                     diagnostic = ConeSimpleDiagnostic("Not a super type", DiagnosticKind.NotASupertype)
                 }
-                superReferenceContainer.resultType =
-                    actualSuperTypeRef.copyWithNewSourceKind(KtFakeSourceElementKind.SuperCallExplicitType)
+                superReferenceContainer.resultType = actualSuperTypeRef.type
                 superReference.replaceSuperTypeRef(actualSuperTypeRef)
             }
             else -> {
@@ -320,8 +312,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
                         diagnostic = ConeAmbiguousSuper(types)
                     }
                 }
-                superReferenceContainer.resultType =
-                    resultType.copyWithNewSourceKind(KtFakeSourceElementKind.SuperCallExplicitType)
+                superReferenceContainer.resultType = resultType.type
                 superReference.replaceSuperTypeRef(resultType)
             }
         }
@@ -336,7 +327,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
         val resultType = buildErrorTypeRef {
             diagnostic = superNotAvailableDiagnostic
         }
-        superReferenceContainer.resultType = resultType
+        superReferenceContainer.resultType = resultType.type
         superReference.replaceSuperTypeRef(resultType)
         superReferenceContainer.replaceCalleeReference(buildErrorNamedReference {
             source = superReferenceContainer.source?.fakeElement(KtFakeSourceElementKind.ReferenceInAtomicQualifiedAccess)
@@ -404,7 +395,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
             val calleeReference = functionCall.calleeReference
             if (
                 (calleeReference is FirResolvedNamedReference || calleeReference is FirErrorNamedReference) &&
-                functionCall.resultType is FirImplicitTypeRef
+                functionCall.resultType == null
             ) {
                 storeTypeFromCallee(functionCall, isLhsOfAssignment = false)
             }
@@ -496,7 +487,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
 
         val integerOperatorCall = buildIntegerLiteralOperatorCall {
             source = originalCall.source
-            typeRef = originalCall.typeRef.resolvedTypeFromPrototype(integerOperatorType)
+            coneTypeOrNull = integerOperatorType
             annotations.addAll(originalCall.annotations)
             typeArguments.addAll(originalCall.typeArguments)
             calleeReference = originalCall.calleeReference
@@ -543,7 +534,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
         block.transformOtherChildren(transformer, data)
         if (data is ResolutionMode.WithExpectedType && data.expectedTypeRef.coneTypeSafe<ConeKotlinType>()?.isUnitOrFlexibleUnit == true) {
             // Unit-coercion
-            block.resultType = data.expectedTypeRef
+            block.resultType = data.expectedTypeRef.type
         } else {
             // Bottom-up propagation: from the return type of the last expression in the block to the block type
             block.writeResultType(session)
@@ -568,7 +559,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
         data: ResolutionMode
     ): FirStatement = whileAnalysing(session, comparisonExpression) {
         return (comparisonExpression.transformChildren(transformer, ResolutionMode.ContextIndependent) as FirComparisonExpression).also {
-            it.resultType = comparisonExpression.typeRef.resolvedTypeFromPrototype(builtinTypes.booleanType.type)
+            it.resultType = builtinTypes.booleanType.type
             dataFlowAnalyzer.exitComparisonExpressionCall(it)
         }
     }
@@ -729,7 +720,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
             source = desugaredSource,
             name = name,
             initializer = initializer,
-            typeRef = initializer.typeRef.copyWithNewSource(desugaredSource),
+            typeRef = initializer.coneTypeOrNull?.toFirResolvedTypeRef(desugaredSource),
         )
 
         fun buildAndResolveOperatorCall(receiver: FirExpression): FirFunctionCall = buildFunctionCall {
@@ -786,7 +777,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
                 statements += unaryVariable.toQualifiedAccess()
             }
         }.apply {
-            replaceTypeRef((statements.last() as FirExpression).typeRef.copyWithNewSource(null))
+            replaceConeTypeOrNull((statements.last() as FirExpression).coneTypeOrNull)
         }
 
         return if (originalExpression is FirSafeCallExpression) {
@@ -813,7 +804,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
         equalityOperatorCall
             .transformAnnotations(transformer, ResolutionMode.ContextIndependent)
             .replaceArgumentList(buildBinaryArgumentList(leftArgumentTransformed, rightArgumentTransformed))
-        equalityOperatorCall.resultType = equalityOperatorCall.typeRef.resolvedTypeFromPrototype(builtinTypes.booleanType.type)
+        equalityOperatorCall.resultType = builtinTypes.booleanType.type
 
         dataFlowAnalyzer.exitEqualityOperatorCall(equalityOperatorCall)
         return equalityOperatorCall
@@ -887,22 +878,15 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
 
         when (resolved.operation) {
             FirOperation.IS, FirOperation.NOT_IS -> {
-                resolved.resultType = session.builtinTypes.booleanType
+                resolved.resultType = session.builtinTypes.booleanType.type
             }
             FirOperation.AS -> {
-                resolved.resultType = buildResolvedTypeRef {
-                    source = conversionTypeRef.source?.fakeElement(KtFakeSourceElementKind.ImplicitTypeRef)
-                    type = conversionTypeRef.coneType
-                    annotations += conversionTypeRef.annotations
-                }
+                resolved.resultType = conversionTypeRef.coneType
             }
             FirOperation.SAFE_AS -> {
-                resolved.resultType =
-                    conversionTypeRef.withReplacedConeType(
-                        conversionTypeRef.coneType.withNullability(
-                            ConeNullability.NULLABLE, session.typeContext,
-                        ),
-                    )
+                resolved.resultType = conversionTypeRef.coneType.withNullability(
+                    ConeNullability.NULLABLE, session.typeContext,
+                )
             }
             else -> error("Unknown type operator: ${resolved.operation}")
         }
@@ -949,7 +933,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
         //   fun <K> checkNotNull(arg: K?): K
         // ...in order to get the not-nullable type of the argument.
 
-        if (checkNotNullCall.calleeReference is FirResolvedNamedReference && checkNotNullCall.resultType !is FirImplicitTypeRef) {
+        if (checkNotNullCall.calleeReference is FirResolvedNamedReference && checkNotNullCall.resultType != null) {
             return checkNotNullCall
         }
 
@@ -970,7 +954,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
         binaryLogicExpression: FirBinaryLogicExpression,
         data: ResolutionMode,
     ): FirStatement = whileAnalysing(session, binaryLogicExpression) {
-        val booleanType = binaryLogicExpression.typeRef.resolvedTypeFromPrototype(builtinTypes.booleanType.type)
+        val booleanType = builtinTypes.booleanType.type.toFirResolvedTypeRef()
         return binaryLogicExpression.also(dataFlowAnalyzer::enterBinaryLogicExpression)
             .transformLeftOperand(this, ResolutionMode.WithExpectedType(booleanType))
             .also(dataFlowAnalyzer::exitLeftBinaryLogicExpressionArgument)
@@ -978,25 +962,22 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
             .transformRightOperand(this, ResolutionMode.WithExpectedType(booleanType))
             .also(dataFlowAnalyzer::exitBinaryLogicExpression)
             .transformOtherChildren(transformer, ResolutionMode.WithExpectedType(booleanType))
-            .also { it.resultType = booleanType }
+            .also { it.resultType = booleanType.type }
     }
 
     override fun transformDesugaredAssignmentValueReferenceExpression(
         desugaredAssignmentValueReferenceExpression: FirDesugaredAssignmentValueReferenceExpression,
-        data: ResolutionMode
+        data: ResolutionMode,
     ): FirStatement {
         val referencedExpression = desugaredAssignmentValueReferenceExpression.expressionRef.value
         if (referencedExpression is FirQualifiedAccessExpression) {
             val typeFromCallee = components.typeFromCallee(referencedExpression)
-            desugaredAssignmentValueReferenceExpression.resultType = typeFromCallee.withReplacedConeType(
-                session.typeApproximator.approximateToSubType(
-                    typeFromCallee.type,
-                    TypeApproximatorConfiguration.FinalApproximationAfterResolutionAndInference
-                )
-            )
+            desugaredAssignmentValueReferenceExpression.resultType = session.typeApproximator.approximateToSubType(
+                typeFromCallee.type,
+                TypeApproximatorConfiguration.FinalApproximationAfterResolutionAndInference
+            ) ?: typeFromCallee.type
         } else {
-            desugaredAssignmentValueReferenceExpression.resultType =
-                referencedExpression.resultType.copyWithNewSourceKind(KtFakeSourceElementKind.ImplicitTypeRef)
+            desugaredAssignmentValueReferenceExpression.resultType = referencedExpression.resultType
         }
         return desugaredAssignmentValueReferenceExpression
     }
@@ -1036,7 +1017,10 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
 
         val result = variableAssignment.transformRValue(
             transformer,
-            withExpectedType(variableAssignment.lValue.typeRef, expectedTypeMismatchIsReportedInChecker = true),
+            withExpectedType(
+                variableAssignment.lValue.coneTypeOrNull?.toFirResolvedTypeRef() ?: FirImplicitTypeRefImplWithoutSource,
+                expectedTypeMismatchIsReportedInChecker = true
+            ),
         )
 
         (result as? FirVariableAssignment)?.let { dataFlowAnalyzer.exitVariableAssignment(it) }
@@ -1089,7 +1073,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
         getClassCall.transformAnnotations(transformer, ResolutionMode.ContextIndependent)
         val arg = getClassCall.argument
         val dataForLhs = if (arg is FirConstExpression<*>) {
-            withExpectedType(arg.typeRef.resolvedTypeFromPrototype(arg.kind.expectedConeType(session)))
+            withExpectedType(arg.kind.expectedConeType(session).toFirResolvedTypeRef())
         } else {
             ResolutionMode.ContextIndependent
         }
@@ -1124,14 +1108,14 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
                             ConeStarProjection
                         }
                     }
-                val coneType = symbol?.constructType(typeArguments, isNullable = false)
-                if (coneType != null) {
-                    lhs.replaceTypeRef(
-                        buildResolvedTypeRef { type = coneType }.also {
+                val type = symbol?.constructType(typeArguments, isNullable = false)
+                if (type != null) {
+                    lhs.replaceConeTypeOrNull(
+                        type.also {
                             session.lookupTracker?.recordTypeResolveAsLookup(it, getClassCall.source, components.file.source)
                         }
                     )
-                    coneType
+                    type
                 } else {
                     lhs.coneType
                 }
@@ -1143,18 +1127,15 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
             else -> {
                 if (!shouldComputeTypeOfGetClassCallWithNotQualifierInLhs(getClassCall)) return transformedGetClassCall
                 val resultType = lhs.resultType
-                if (resultType is FirErrorTypeRef) {
-                    resultType.coneType
+                if (resultType is ConeErrorType) {
+                    resultType
                 } else {
-                    ConeKotlinTypeProjectionOut(resultType.coneType)
+                    ConeKotlinTypeProjectionOut(resultType!!)
                 }
             }
         }
 
-        transformedGetClassCall.resultType =
-            buildResolvedTypeRef {
-                type = StandardClassIds.KClass.constructClassLikeType(arrayOf(typeOfExpression), false)
-            }
+        transformedGetClassCall.resultType = StandardClassIds.KClass.constructClassLikeType(arrayOf(typeOfExpression), false)
         dataFlowAnalyzer.exitGetClassCall(transformedGetClassCall)
         return transformedGetClassCall
     }
@@ -1206,7 +1187,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
         }
 
         dataFlowAnalyzer.exitConstExpression(constExpression as FirConstExpression<*>)
-        constExpression.resultType = constExpression.resultType.resolvedTypeFromPrototype(type)
+        constExpression.resultType = type
 
         return when (val resolvedType = constExpression.coneType) {
             is ConeErrorType -> buildErrorExpression {
@@ -1513,11 +1494,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
                 statements += indexVariables
                 statements += setCall
             }.also {
-                it.replaceTypeRef(
-                    buildResolvedTypeRef {
-                        type = session.builtinTypes.unitType.type
-                    }
-                )
+                it.replaceConeTypeOrNull(session.builtinTypes.unitType.type)
             }
         }
     }
@@ -1537,7 +1514,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
             source = lhsGetCall.explicitReceiver?.source?.fakeElement(KtFakeSourceElementKind.DesugaredCompoundAssignment),
             name = SpecialNames.ARRAY,
             initializer = initializer,
-            typeRef = initializer.typeRef.copyWithNewSourceKind(KtFakeSourceElementKind.DesugaredCompoundAssignment),
+            typeRef = initializer.coneTypeOrNull?.toFirResolvedTypeRef(initializer.source?.fakeElement(KtFakeSourceElementKind.DesugaredCompoundAssignment)),
         )
 
         val indexVariables = lhsGetCall.arguments.flatMap {
@@ -1551,7 +1528,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
                 source = index.source?.fakeElement(KtFakeSourceElementKind.DesugaredCompoundAssignment),
                 name = SpecialNames.subscribeOperatorIndex(i),
                 initializer = index,
-                typeRef = index.typeRef,
+                typeRef = index.coneTypeOrNull?.toFirResolvedTypeRef(),
             )
         }
 
@@ -1581,7 +1558,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
                             arguments += indicesQualifiedAccess.subList(i, i + varargSize)
                             i += varargSize
                             source = argument.source
-                            typeRef = argument.typeRef
+                            coneTypeOrNull = argument.coneTypeOrNull
                             varargElementType = argument.varargElementType
                         }
                     } else {
@@ -1590,7 +1567,7 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
                 }
             }
             origin = FirFunctionCallOrigin.Operator
-            typeRef = lhsGetCall.typeRef
+            coneTypeOrNull = lhsGetCall.coneTypeOrNull
         }
 
         val generator = GeneratorOfPlusAssignCalls(
@@ -1665,14 +1642,11 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
 
     override fun transformAnonymousObjectExpression(
         anonymousObjectExpression: FirAnonymousObjectExpression,
-        data: ResolutionMode
+        data: ResolutionMode,
     ): FirStatement {
         anonymousObjectExpression.transformAnonymousObject(transformer, data)
-        if (anonymousObjectExpression.typeRef !is FirResolvedTypeRef) {
-            anonymousObjectExpression.resultType = buildResolvedTypeRef {
-                source = anonymousObjectExpression.source?.fakeElement(KtFakeSourceElementKind.ImplicitTypeRef)
-                this.type = anonymousObjectExpression.anonymousObject.defaultType()
-            }
+        if (anonymousObjectExpression.coneTypeOrNull == null) {
+            anonymousObjectExpression.resultType = anonymousObjectExpression.anonymousObject.defaultType()
         }
         dataFlowAnalyzer.exitAnonymousObjectExpression(anonymousObjectExpression)
         return anonymousObjectExpression
@@ -1690,17 +1664,15 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
 
     internal fun storeTypeFromCallee(access: FirQualifiedAccessExpression, isLhsOfAssignment: Boolean) {
         val typeFromCallee = components.typeFromCallee(access)
-        access.resultType = typeFromCallee.withReplacedConeType(
-            if (isLhsOfAssignment) {
-                session.typeApproximator.approximateToSubType(
-                    typeFromCallee.type, TypeApproximatorConfiguration.FinalApproximationAfterResolutionAndInference
-                )
-            } else {
-                session.typeApproximator.approximateToSuperType(
-                    typeFromCallee.type, TypeApproximatorConfiguration.FinalApproximationAfterResolutionAndInference
-                )
-            }
-        )
+        access.resultType = if (isLhsOfAssignment) {
+            session.typeApproximator.approximateToSubType(
+                typeFromCallee.type, TypeApproximatorConfiguration.FinalApproximationAfterResolutionAndInference
+            )
+        } else {
+            session.typeApproximator.approximateToSuperType(
+                typeFromCallee.type, TypeApproximatorConfiguration.FinalApproximationAfterResolutionAndInference
+            )
+        } ?: typeFromCallee.type
     }
 
 }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/contracts/FirAbstractContractResolveTransformerDispatcher.kt

@@ -156,7 +156,7 @@ abstract class FirAbstractContractResolveTransformerDispatcher(
             val resolvedContractCall = withContractModeDisabled {
                 contractDescription.contractCall
                     .transformSingle(transformer, ResolutionMode.ContextIndependent)
-                    .apply { replaceTypeRef(session.builtinTypes.unitType) }
+                    .apply { replaceConeTypeOrNull(session.builtinTypes.unitType.type) }
             }
 
             if (resolvedContractCall.toResolvedCallableSymbol()?.callableId != FirContractsDslNames.CONTRACT) {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/plugin/AbstractFirSpecificAnnotationResolveTransformer.kt

@@ -37,7 +37,6 @@ import org.jetbrains.kotlin.fir.types.builder.buildStarProjection
 import org.jetbrains.kotlin.fir.types.builder.buildTypeProjectionWithVariance
 import org.jetbrains.kotlin.fir.types.builder.buildUserTypeRef
 import org.jetbrains.kotlin.fir.types.impl.ConeClassLikeTypeImpl
-import org.jetbrains.kotlin.fir.types.impl.FirImplicitUnitTypeRef
 import org.jetbrains.kotlin.fir.types.impl.FirQualifierPartImpl
 import org.jetbrains.kotlin.fir.types.impl.FirTypeArgumentListImpl
 import org.jetbrains.kotlin.fir.visitors.FirDefaultTransformer
@@ -144,7 +143,7 @@ abstract class AbstractFirSpecificAnnotationResolveTransformer(
                     source = receiver.source
                     packageFqName = symbol.classId.packageFqName
                     relativeClassFqName = symbol.classId.relativeClassName
-                    typeRef = FirImplicitUnitTypeRef(receiver.typeRef.source)
+                    coneTypeOrNull = session.builtinTypes.unitType.type
                     this.symbol = symbol
                     isFullyQualified = segments.isNotEmpty()
                 }
@@ -190,7 +189,7 @@ abstract class AbstractFirSpecificAnnotationResolveTransformer(
 
             calleeSymbol.containingClassLookupTag()
                 ?.let { ConeClassLikeTypeImpl(it, emptyArray(), false) }
-                ?.let { replaceTypeRef(typeRef.resolvedTypeFromPrototype(it)) }
+                ?.let { replaceConeTypeOrNull(it) }
         }
     }
 

compiler/fir/semantics/src/org/jetbrains/kotlin/fir/FirLookupTrackerComponent.kt

@@ -37,25 +37,25 @@ fun FirLookupTrackerComponent.recordTypeLookup(typeRef: FirTypeRef, inScopes: Li
 
 fun FirLookupTrackerComponent.recordTypeResolveAsLookup(typeRef: FirTypeRef, source: KtSourceElement?, fileSource: KtSourceElement?) {
     if (typeRef !is FirResolvedTypeRef) return // TODO: check if this is the correct behavior
-    if (source == null && fileSource == null) return // TODO: investigate all cases
+    recordTypeResolveAsLookup(typeRef.type, source, fileSource)
+}
 
-    fun recordIfValid(type: ConeKotlinType) {
-        if (type is ConeErrorType) return // TODO: investigate whether some cases should be recorded, e.g. unresolved
-        type.classId?.let {
-            if (!it.isLocal) {
-                if (it.shortClassName.asString() != "Companion") {
-                    recordLookup(it.shortClassName, it.packageFqName.asString(), source, fileSource)
-                } else {
-                    recordLookup(it.outerClassId!!.shortClassName, it.outerClassId!!.packageFqName.asString(), source, fileSource)
-                }
+fun FirLookupTrackerComponent.recordTypeResolveAsLookup(type: ConeKotlinType?, source: KtSourceElement?, fileSource: KtSourceElement?) {
+    if (type == null) return
+    if (source == null && fileSource == null) return // TODO: investigate all cases
+    if (type is ConeErrorType) return // TODO: investigate whether some cases should be recorded, e.g. unresolved
+    type.classId?.let {
+        if (!it.isLocal) {
+            if (it.shortClassName.asString() != "Companion") {
+                recordLookup(it.shortClassName, it.packageFqName.asString(), source, fileSource)
+            } else {
+                recordLookup(it.outerClassId!!.shortClassName, it.outerClassId!!.packageFqName.asString(), source, fileSource)
             }
         }
-        type.typeArguments.forEach {
-            if (it is ConeKotlinType) recordIfValid(it)
-        }
     }
-
-    recordIfValid(typeRef.type)
+    type.typeArguments.forEach {
+        if (it is ConeKotlinType) recordTypeResolveAsLookup(it, source, fileSource)
+    }
 }
 
 

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

@@ -16,13 +16,13 @@ import org.jetbrains.kotlin.fir.resolve.dfa.FlowPath
 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.ConeKotlinType
 import org.jetbrains.kotlin.fir.types.coneType
-import org.jetbrains.kotlin.fir.types.impl.FirImplicitNothingTypeRef
+import org.jetbrains.kotlin.fir.types.constructClassLikeType
 import org.jetbrains.kotlin.fir.types.isNothing
 import org.jetbrains.kotlin.fir.visitors.FirTransformer
 import org.jetbrains.kotlin.fir.visitors.FirVisitor
+import org.jetbrains.kotlin.name.StandardClassIds
 import org.jetbrains.kotlin.utils.SmartList
 
 @RequiresOptIn
@@ -869,16 +869,14 @@ class WhenSubjectExpressionExitNode(owner: ControlFlowGraph, override val fir: F
 
 object FirStub : FirExpression() {
     override val source: KtSourceElement? get() = null
-    override val typeRef: FirTypeRef = FirImplicitNothingTypeRef(null)
+    override val coneTypeOrNull: ConeKotlinType = StandardClassIds.Nothing.constructClassLikeType()
     override val annotations: List<FirAnnotation> get() = listOf()
 
     override fun <R, D> acceptChildren(visitor: FirVisitor<R, D>, data: D) {}
     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) }
+    override fun replaceConeTypeOrNull(newConeTypeOrNull: ConeKotlinType?) { assert(newConeTypeOrNull?.isNothing == true) }
 }
 
 class FakeExpressionEnterNode(owner: ControlFlowGraph, level: Int) : CFGNode<FirStub>(owner, level), GraphEnterNodeMarker, GraphExitNodeMarker {

compiler/fir/tree/src/org/jetbrains/kotlin/fir/EnumClassUtils.kt

@@ -69,7 +69,7 @@ fun FirRegularClassBuilder.generateValuesFunction(
         symbol = FirNamedFunctionSymbol(CallableId(packageFqName, classFqName, ENUM_VALUES))
         resolvePhase = this@generateValuesFunction.resolvePhase
         body = buildEmptyExpressionBlock().also {
-            it.replaceType(returnTypeRef.type)
+            it.replaceConeTypeOrNull(returnTypeRef.type)
         }
     }.apply {
         containingClassForStaticMemberAttr = this@generateValuesFunction.symbol.toLookupTag()
@@ -126,7 +126,7 @@ fun FirRegularClassBuilder.generateValueOfFunction(
         }
         resolvePhase = this@generateValueOfFunction.resolvePhase
         body = buildEmptyExpressionBlock().also {
-            it.replaceType(returnTypeRef.type)
+            it.replaceConeTypeOrNull(returnTypeRef.type)
         }
     }.apply {
         containingClassForStaticMemberAttr = this@generateValueOfFunction.symbol.toLookupTag()

compiler/fir/tree/src/org/jetbrains/kotlin/fir/expressions/builder/FirConstExpressionBuilder.kt

@@ -24,20 +24,20 @@ fun <T> buildConstExpression(
     return FirConstExpressionImpl(source, null, annotations.toMutableOrEmpty(), kind, value).also {
         if (setType) {
             when (kind) {
-                ConstantValueKind.Boolean -> it.type = StandardClassIds.Boolean.constructClassLikeType()
-                ConstantValueKind.Byte -> it.type = StandardClassIds.Byte.constructClassLikeType()
-                ConstantValueKind.Char -> it.type = StandardClassIds.Char.constructClassLikeType()
-                ConstantValueKind.Double -> it.type = StandardClassIds.Double.constructClassLikeType()
-                ConstantValueKind.Float -> it.type = StandardClassIds.Float.constructClassLikeType()
-                ConstantValueKind.Int -> it.type = StandardClassIds.Int.constructClassLikeType()
-                ConstantValueKind.Long -> it.type = StandardClassIds.Long.constructClassLikeType()
-                ConstantValueKind.Null -> it.type = StandardClassIds.Any.constructClassLikeType(isNullable = true)
-                ConstantValueKind.Short -> it.type = StandardClassIds.Short.constructClassLikeType()
-                ConstantValueKind.String -> it.type = StandardClassIds.String.constructClassLikeType()
-                ConstantValueKind.UnsignedByte -> it.type = StandardClassIds.UByte.constructClassLikeType()
-                ConstantValueKind.UnsignedInt -> it.type = StandardClassIds.UInt.constructClassLikeType()
-                ConstantValueKind.UnsignedLong -> it.type = StandardClassIds.ULong.constructClassLikeType()
-                ConstantValueKind.UnsignedShort -> it.type = StandardClassIds.UShort.constructClassLikeType()
+                ConstantValueKind.Boolean -> it.coneTypeOrNull = StandardClassIds.Boolean.constructClassLikeType()
+                ConstantValueKind.Byte -> it.coneTypeOrNull = StandardClassIds.Byte.constructClassLikeType()
+                ConstantValueKind.Char -> it.coneTypeOrNull = StandardClassIds.Char.constructClassLikeType()
+                ConstantValueKind.Double -> it.coneTypeOrNull = StandardClassIds.Double.constructClassLikeType()
+                ConstantValueKind.Float -> it.coneTypeOrNull = StandardClassIds.Float.constructClassLikeType()
+                ConstantValueKind.Int -> it.coneTypeOrNull = StandardClassIds.Int.constructClassLikeType()
+                ConstantValueKind.Long -> it.coneTypeOrNull = StandardClassIds.Long.constructClassLikeType()
+                ConstantValueKind.Null -> it.coneTypeOrNull = StandardClassIds.Any.constructClassLikeType(isNullable = true)
+                ConstantValueKind.Short -> it.coneTypeOrNull = StandardClassIds.Short.constructClassLikeType()
+                ConstantValueKind.String -> it.coneTypeOrNull = StandardClassIds.String.constructClassLikeType()
+                ConstantValueKind.UnsignedByte -> it.coneTypeOrNull = StandardClassIds.UByte.constructClassLikeType()
+                ConstantValueKind.UnsignedInt -> it.coneTypeOrNull = StandardClassIds.UInt.constructClassLikeType()
+                ConstantValueKind.UnsignedLong -> it.coneTypeOrNull = StandardClassIds.ULong.constructClassLikeType()
+                ConstantValueKind.UnsignedShort -> it.coneTypeOrNull = StandardClassIds.UShort.constructClassLikeType()
                 ConstantValueKind.IntegerLiteral,
                 ConstantValueKind.UnsignedIntegerLiteral,
                 ConstantValueKind.Error,

compiler/frontend.common/src/org/jetbrains/kotlin/KtSourceElement.kt

@@ -209,11 +209,6 @@ sealed class KtFakeSourceElementKind(final override val shouldSkipErrorTypeRepor
     // where `Supertype` has a fake source
     object SuperCallImplicitType : KtFakeSourceElementKind()
 
-    // Consider `super<Supertype>.foo()`. The source PSI `Supertype` is referenced by both the qualified access expression
-    // `super<Supertype>` and the calleeExpression `super<Supertype>`. To avoid having two FIR elements sharing the same source, this fake
-    // source is assigned to the qualified access expression.
-    object SuperCallExplicitType : KtFakeSourceElementKind(shouldSkipErrorTypeReporting = true)
-
     // fun foo(vararg args: Int) {}
     // fun bar(1, 2, 3) --> [resolved] fun bar(VarargArgument(1, 2, 3))
     object VarargArgument : KtFakeSourceElementKind()

compiler/testData/diagnostics/tests/EnumEntryAsType.fir.kt

@@ -17,7 +17,7 @@ class MyColor(val x: Color.<!ENUM_ENTRY_AS_TYPE!>RED<!>, y: Color.<!ENUM_ENTRY_A
         class Local : Color.<!ENUM_ENTRY_AS_TYPE!>RED<!>
         fun local(arg: Color.<!ENUM_ENTRY_AS_TYPE!>RED<!>): Color.<!ENUM_ENTRY_AS_TYPE!>RED<!> = arg
         val temp: Color.<!ENUM_ENTRY_AS_TYPE!>RED<!> = Color.RED
-        temp as? Color.<!ENUM_ENTRY_AS_TYPE, ENUM_ENTRY_AS_TYPE!>RED<!>
+        temp as? Color.<!ENUM_ENTRY_AS_TYPE!>RED<!>
         if (temp is <!IS_ENUM_ENTRY!>Color.RED<!>) {
         return temp as Color.<!ENUM_ENTRY_AS_TYPE!>RED<!>
     }

compiler/testData/diagnostics/tests/kt49438.fir.kt

@@ -1,7 +1,7 @@
 fun <K> foo(x: K) {}
 val x1 = foo<(<!UNRESOLVED_REFERENCE!>unresolved<!>) -> Float> { it.<!UNRESOLVED_REFERENCE!>toFloat<!>() }
 val x2 = foo<(<!UNRESOLVED_REFERENCE!>unresolved<!>) -> Float> { <!CANNOT_INFER_PARAMETER_TYPE!>it<!> -> it.<!UNRESOLVED_REFERENCE!>toFloat<!>() }
-val x3 = foo<<!UNRESOLVED_REFERENCE!>unresolved<!>.() -> Float> { this.<!UNRESOLVED_REFERENCE!>toFloat<!>() }
+val x3 = foo<<!UNRESOLVED_REFERENCE!>unresolved<!>.() -> Float> { <!CANNOT_INFER_PARAMETER_TYPE!>this<!>.<!UNRESOLVED_REFERENCE!>toFloat<!>() }
 val x4 = foo<(Array<<!UNRESOLVED_REFERENCE!>unresolved<!>>) -> Int> { it.size }
 
 fun <T> bar() = foo<(T) -> String> { it.toString() }

compiler/testData/diagnostics/tests/resolve/HiddenDeclarations.fir.kt

@@ -40,7 +40,7 @@ open class A {
     fun foo() {
         <!UNRESOLVED_REFERENCE!>topLevelFun<!>()
         <!UNRESOLVED_REFERENCE!>topLevelFun<!>(1)
-        <!UNRESOLVED_REFERENCE!>topLevelProperty<!><!UNRESOLVED_REFERENCE, UNRESOLVED_REFERENCE, UNRESOLVED_REFERENCE, UNRESOLVED_REFERENCE!>++<!>
+        <!UNRESOLVED_REFERENCE!>topLevelProperty<!><!UNRESOLVED_REFERENCE, UNRESOLVED_REFERENCE!>++<!>
         "".<!UNRESOLVED_REFERENCE!>topLevelExtensionFun<!>()
         1.<!UNRESOLVED_REFERENCE!>topLevelExtensionFun<!>()
         "".<!UNRESOLVED_REFERENCE!>topLevelExtensionProperty<!>

compiler/testData/diagnostics/tests/smartCasts/variables/reassignedDependency.fir.kt

@@ -75,3 +75,12 @@ fun test5() {
     c.x<!UNSAFE_CALL!>.<!>length // bad
     d.x.length // ok
 }
+
+fun test6() {
+    var c: C? = null
+    var maybeC: C? = C("")
+    if (c == null) {
+        c = maybeC ?: throw Exception()
+    }
+    c.x
+}

compiler/testData/diagnostics/tests/smartCasts/variables/reassignedDependency.kt

@@ -75,3 +75,12 @@ fun test5() {
     c.x<!UNSAFE_CALL!>.<!>length // bad
     <!DEBUG_INFO_SMARTCAST!>d.x<!>.length // ok
 }
+
+fun test6() {
+    var c: C? = null
+    var maybeC: C? = C("")
+    if (c == null) {
+        c = maybeC ?: throw Exception()
+    }
+    <!DEBUG_INFO_SMARTCAST!>c<!>.x
+}

compiler/testData/diagnostics/testsWithStdLib/builderInference/typeVariableShouldNotBeFixed.fir.kt

@@ -25,7 +25,7 @@ fun <M> materialize(): Processor<M> = TODO()
 private fun foo(model: Model) {
     <!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER("M")!>materialize<!>().<!NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER("T")!>apply<!> {
         context(
-            this,
+            <!CANNOT_INFER_PARAMETER_TYPE!>this<!>,
             Exec { m, p -> p.process(m) } // Note: Builder inference
         )
     }

compiler/visualizer/render-fir/src/org/jetbrains/kotlin/compiler/visualizer/FirVisualizer.kt

@@ -47,7 +47,7 @@ class FirVisualizer(private val firFile: FirFile) : BaseRenderer() {
 
     private fun Stack.push(
         levelName: String,
-        defaultValues: MutableList<String> = mutableListOf()
+        defaultValues: MutableList<String> = mutableListOf(),
     ) = this.add(levelName to defaultValues)
 
     private fun Stack.pop() = this.removeAt(this.size - 1)
@@ -164,7 +164,7 @@ class FirVisualizer(private val firFile: FirFile) : BaseRenderer() {
             if (function.isLocal) stack.addName(function.name ?: ANONYMOUS_NAME)
             stack.push((function.name ?: ANONYMOUS_NAME))
             if (function.equalsToken != null) {
-                function.bodyExpression!!.firstOfTypeWithRender<FirReturnExpression>(function.equalsToken) { this.result.typeRef }
+                function.bodyExpression!!.firstOfTypeWithRender<FirReturnExpression>(function.equalsToken) { this.result.coneType.toFirResolvedTypeRef() }
                     ?: function.firstOfTypeWithRender<FirCallableDeclaration>(function.equalsToken) { this.returnTypeRef }
             }
             super.visitNamedFunction(function)
@@ -249,12 +249,12 @@ class FirVisualizer(private val firFile: FirFile) : BaseRenderer() {
         }
 
         override fun visitIfExpression(expression: KtIfExpression) {
-            expression.firstOfTypeWithRender<FirWhenExpression> { this.typeRef }
+            expression.firstOfTypeWithRender<FirWhenExpression> { this.coneType.toFirResolvedTypeRef() }
             super.visitIfExpression(expression)
         }
 
         override fun visitWhenExpression(expression: KtWhenExpression) {
-            expression.firstOfTypeWithRender<FirWhenExpression> { this.typeRef }
+            expression.firstOfTypeWithRender<FirWhenExpression> { this.coneType.toFirResolvedTypeRef() }
             super.visitWhenExpression(expression)
         }
 
@@ -306,7 +306,7 @@ class FirVisualizer(private val firFile: FirFile) : BaseRenderer() {
         }
 
         override fun visitWhenEntry(ktWhenEntry: KtWhenEntry) {
-            ktWhenEntry.firstOfTypeWithRender<FirWhenBranch>(ktWhenEntry.expression) { this.result.typeRef }
+            ktWhenEntry.firstOfTypeWithRender<FirWhenBranch>(ktWhenEntry.expression) { this.result.coneType.toFirResolvedTypeRef() }
             super.visitWhenEntry(ktWhenEntry)
         }
 
@@ -564,7 +564,7 @@ class FirVisualizer(private val firFile: FirFile) : BaseRenderer() {
                     fir.receiverParameter?.accept(this, data)
                     data.append(".").append(callableName)
                 }
-                call.dispatchReceiver.typeRef.annotations.any { it.isExtensionFunctionAnnotationCall } -> {
+                call.dispatchReceiver.coneType.isExtensionFunctionType -> {
                     withExtensionFunctionType = true
                     fir.valueParameters.first().returnTypeRef.accept(this, data)
                     data.append(".").append(callableName)
@@ -786,7 +786,7 @@ class FirVisualizer(private val firFile: FirFile) : BaseRenderer() {
         override fun <T> visitConstExpression(constExpression: FirConstExpression<T>, data: StringBuilder) {
             when (constExpression.kind) {
                 ConstantValueKind.String -> return
-                ConstantValueKind.Null -> constExpression.typeRef.accept(this, data)
+                ConstantValueKind.Null -> constExpression.coneType.tryToRenderConeAsFunctionType(data)
                 else -> data.append(constExpression.kind)
             }
         }
@@ -796,7 +796,7 @@ class FirVisualizer(private val firFile: FirFile) : BaseRenderer() {
             when {
                 fir is FirRegularClass && fir.classKind != ClassKind.ENUM_CLASS && fir.companionObjectSymbol?.defaultType() == resolvedQualifier.coneTypeSafe() -> {
                     data.append("companion object ")
-                    data.append(resolvedQualifier.typeRef.render()).append(": ")
+                    data.append(resolvedQualifier.coneType.toFirResolvedTypeRef().render()).append(": ")
                     data.append(fir.symbol.classId.asString().removeCurrentFilePackage())
                 }
                 fir is FirClass -> {

plugins/assign-plugin/assign-plugin.k2/src/org/jetbrains/kotlin/assignment/plugin/k2/FirAssignmentPluginAssignAltererExtension.kt

@@ -54,7 +54,7 @@ class FirAssignmentPluginAssignAltererExtension(
             source = variableAssignment.source?.fakeElement(KtFakeSourceElementKind.DesugaredCompoundAssignment)
             explicitReceiver = buildPropertyAccessExpression {
                 source = leftArgument.source
-                typeRef = leftResolvedType
+                coneTypeOrNull = leftResolvedType.type
                 calleeReference = leftArgument
                 (variableAssignment.lValue as? FirQualifiedAccessExpression)?.typeArguments?.let(typeArguments::addAll)
                 annotations += variableAssignment.annotations
@@ -71,4 +71,4 @@ class FirAssignmentPluginAssignAltererExtension(
             origin = FirFunctionCallOrigin.Regular
         }
     }
-}
+}

plugins/fir-plugin-prototype/src/org/jetbrains/kotlin/fir/plugin/generators/MembersOfSerializerGenerator.kt

@@ -57,7 +57,7 @@ class MembersOfSerializerGenerator(session: FirSession) : FirDeclarationGenerati
         val function = createMemberFunction(owner, Key, callableId.callableName, session.builtinTypes.unitType.type) {
             valueParameter(X_NAME, argumentClassId.createConeType(session))
         }.apply {
-            replaceBody(buildBlock {}.apply { replaceTypeRef(session.builtinTypes.unitType) })
+            replaceBody(buildBlock {}.apply { replaceConeTypeOrNull(session.builtinTypes.unitType.type) })
         }
         return listOf(function.symbol)
     }

plugins/scripting/scripting-compiler/src/org/jetbrains/kotlin/scripting/compiler/plugin/services/FirScriptConfigurationExtensionImpl.kt

@@ -26,8 +26,11 @@ import org.jetbrains.kotlin.fir.symbols.SymbolInternals
 import org.jetbrains.kotlin.fir.symbols.impl.FirPropertySymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
 import org.jetbrains.kotlin.fir.types.builder.buildUserTypeRef
+import org.jetbrains.kotlin.fir.types.coneTypeOrNull
+import org.jetbrains.kotlin.fir.types.impl.FirImplicitTypeRefImplWithoutSource
 import org.jetbrains.kotlin.fir.types.impl.FirQualifierPartImpl
 import org.jetbrains.kotlin.fir.types.impl.FirTypeArgumentListImpl
+import org.jetbrains.kotlin.fir.types.toFirResolvedTypeRef
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
@@ -148,12 +151,12 @@ class FirScriptConfiguratorExtensionImpl(
                         moduleData = session.moduleData
                         origin = FirDeclarationOrigin.ScriptCustomization.ResultProperty
                         initializer = lastExpression
-                        returnTypeRef = lastExpression.typeRef
+                        returnTypeRef = lastExpression.coneTypeOrNull?.toFirResolvedTypeRef() ?: FirImplicitTypeRefImplWithoutSource
                         getter = FirDefaultPropertyGetter(
                             lastExpression.source,
                             session.moduleData,
                             FirDeclarationOrigin.ScriptCustomization.ResultProperty,
-                            lastExpression.typeRef,
+                            lastExpression.coneTypeOrNull?.toFirResolvedTypeRef() ?: FirImplicitTypeRefImplWithoutSource,
                             Visibilities.Public,
                             this.symbol,
                         )