FIR2IR: provide more precise conversion type context at some use-sites

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

@@ -123,6 +123,9 @@ class ConversionTypeContext internal constructor(
             definitelyNotNull = false, origin = ConversionTypeOrigin.DEFAULT, invariantProjection = false
         )
         internal val WITH_INVARIANT = DEFAULT.withInvariantProjections()
+        internal val IN_SETTER = ConversionTypeContext(
+            definitelyNotNull = false, origin = ConversionTypeOrigin.SETTER, invariantProjection = false
+        )
     }
 }
 

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrConversionScope.kt

@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.fir.declarations.FirProperty
 import org.jetbrains.kotlin.fir.declarations.FirPropertyAccessor
 import org.jetbrains.kotlin.fir.expressions.FirReturnExpression
 import org.jetbrains.kotlin.ir.declarations.*
+import org.jetbrains.kotlin.ir.util.isSetter
 import org.jetbrains.kotlin.ir.util.parentClassOrNull
 
 class Fir2IrConversionScope {
@@ -134,6 +135,9 @@ class Fir2IrConversionScope {
 
     fun parent(): IrDeclarationParent? = parentStack.lastOrNull()
 
+    fun defaultConversionTypeContext(): ConversionTypeContext =
+        if ((parent() as? IrFunction)?.isSetter == true) ConversionTypeContext.IN_SETTER else ConversionTypeContext.DEFAULT
+
     fun dispatchReceiverParameter(irClass: IrClass): IrValueParameter? {
         for (function in functionStack.asReversed()) {
             if (function.parentClassOrNull == irClass) {

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrImplicitCastInserter.kt

@@ -30,9 +30,13 @@ class Fir2IrImplicitCastInserter(
     private val components: Fir2IrComponents
 ) : Fir2IrComponents by components, FirDefaultVisitor<IrElement, IrElement>() {
 
-    private fun FirTypeRef.toIrType(): IrType = with(typeConverter) { toIrType() }
+    private fun FirTypeRef.toIrType(conversionTypeContext: ConversionTypeContext): IrType = with(typeConverter) {
+        toIrType(conversionTypeContext)
+    }
 
-    private fun ConeKotlinType.toIrType(): IrType = with(typeConverter) { toIrType() }
+    private fun ConeKotlinType.toIrType(conversionTypeContext: ConversionTypeContext): IrType = with(typeConverter) {
+        toIrType(conversionTypeContext)
+    }
 
     override fun visitElement(element: FirElement, data: IrElement): IrElement {
         TODO("Should not be here: ${element::class}: ${element.render()}")
@@ -99,7 +103,7 @@ class Fir2IrImplicitCastInserter(
     override fun visitExpression(expression: FirExpression, data: IrElement): IrElement {
         return when (expression) {
             is FirBlock -> (data as IrContainerExpression).insertImplicitCasts()
-            is FirUnitExpression -> (data as IrExpression).let { coerceToUnitIfNeeded(it, irBuiltIns) }
+            is FirUnitExpression -> coerceToUnitIfNeeded(data as IrExpression, irBuiltIns)
             else -> data
         }
     }
@@ -108,7 +112,7 @@ class Fir2IrImplicitCastInserter(
         return when (statement) {
             is FirTypeAlias -> data
             FirStubStatement -> data
-            is FirUnitExpression -> (data as IrExpression).let { coerceToUnitIfNeeded(it, irBuiltIns) }
+            is FirUnitExpression -> coerceToUnitIfNeeded(data as IrExpression, irBuiltIns)
             is FirBlock -> (data as IrContainerExpression).insertImplicitCasts()
             else -> statement.accept(this, data)
         }
@@ -207,7 +211,7 @@ class Fir2IrImplicitCastInserter(
             }
             valueType.coneTypeSafe<ConeDynamicType>() != null -> {
                 if (expectedType.coneType !is ConeDynamicType && !expectedType.isNullableAny) {
-                    implicitCast(this, expectedType.toIrType())
+                    implicitCast(this, expectedType.toIrType(ConversionTypeContext.DEFAULT))
                 } else {
                     this
                 }
@@ -298,6 +302,7 @@ class Fir2IrImplicitCastInserter(
         original: IrExpression,
         originalTypeRef: FirTypeRef,
         calleeReference: FirReference,
+        conversionTypeContext: ConversionTypeContext,
     ): IrExpression {
         val referencedDeclaration = (calleeReference.resolvedSymbol as? FirCallableSymbol<*>)?.unwrapCallRepresentative()?.fir
 
@@ -310,19 +315,23 @@ class Fir2IrImplicitCastInserter(
         val castType = originalTypeRef.coneTypeSafe<ConeIntersectionType>()
         castType?.intersectedTypes?.forEach { componentType ->
             if (AbstractTypeChecker.isSubtypeOf(session.typeContext, componentType, starProjectedDispatchReceiver)) {
-                return implicitCastOrExpression(original, componentType)
+                return implicitCastOrExpression(original, componentType, conversionTypeContext)
             }
         }
 
-        return implicitCastOrExpression(original, originalTypeRef)
+        return implicitCastOrExpression(original, originalTypeRef, conversionTypeContext)
     }
 
-    private fun implicitCastOrExpression(original: IrExpression, castType: ConeKotlinType): IrExpression {
-        return implicitCastOrExpression(original, castType.toIrType())
+    private fun implicitCastOrExpression(
+        original: IrExpression, castType: ConeKotlinType, conversionTypeContext: ConversionTypeContext = ConversionTypeContext.DEFAULT
+    ): IrExpression {
+        return implicitCastOrExpression(original, castType.toIrType(conversionTypeContext))
     }
 
-    private fun implicitCastOrExpression(original: IrExpression, castType: FirTypeRef): IrExpression {
-        return implicitCastOrExpression(original, castType.toIrType())
+    private fun implicitCastOrExpression(
+        original: IrExpression, castType: FirTypeRef, conversionTypeContext: ConversionTypeContext = ConversionTypeContext.DEFAULT
+    ): IrExpression {
+        return implicitCastOrExpression(original, castType.toIrType(conversionTypeContext))
     }
 
     internal fun implicitCastOrExpression(original: IrExpression, castType: IrType): IrExpression {

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

@@ -672,7 +672,10 @@ class Fir2IrVisitor(
         }?.run {
             if (expression is FirQualifiedAccessExpression && expression.calleeReference is FirSuperReference) return@run this
 
-            implicitCastInserter.implicitCastFromDispatchReceiver(this, expression.typeRef, calleeReference)
+            implicitCastInserter.implicitCastFromDispatchReceiver(
+                this, expression.typeRef, calleeReference,
+                conversionScope.defaultConversionTypeContext()
+            )
         }
     }
 

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

@@ -59,10 +59,11 @@ class CallAndReferenceGenerator(
     private val approximator = ConeTypeApproximator(session.typeContext, session.languageVersionSettings)
     private val adapterGenerator = AdapterGenerator(components, conversionScope)
 
-    private fun FirTypeRef.toIrType(): IrType = with(typeConverter) { toIrType() }
+    private fun FirTypeRef.toIrType(): IrType =
+        with(typeConverter) { toIrType(conversionScope.defaultConversionTypeContext()) }
 
-    private fun ConeKotlinType.toIrType(conversionTypeContext: ConversionTypeContext = ConversionTypeContext.DEFAULT): IrType =
-        with(typeConverter) { toIrType(conversionTypeContext) }
+    private fun ConeKotlinType.toIrType(): IrType =
+        with(typeConverter) { toIrType(conversionScope.defaultConversionTypeContext()) }
 
     fun convertToIrCallableReference(
         callableReferenceAccess: FirCallableReferenceAccess,