From 289efd47b26402b6076327ecac1fe07b7b185f88 Mon Sep 17 00:00:00 2001
From: Mikhail Glukhikh <mikhail.glukhikh@jetbrains.com>
Date: Thu, 22 Oct 2020 10:43:47 +0300
Subject: [PATCH] [FIR2IR] Cleanup code around implicit casts

---
 .../kotlin/fir/backend/Fir2IrVisitor.kt       | 41 +++++++++++--------
 1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt
index 45ccd01db2a..5d36652269d 100644
--- a/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt
+++ b/compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt
@@ -7,7 +7,6 @@ package org.jetbrains.kotlin.fir.backend
 
 import org.jetbrains.kotlin.KtNodeTypes
 import org.jetbrains.kotlin.descriptors.ClassKind
-import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.fir.*
@@ -424,10 +423,19 @@ class Fir2IrVisitor(
         return visitQualifiedAccessExpression(thisReceiverExpression, data)
     }
 
-    private fun implicitCastOrExpression(original: IrExpression, castType: IrType, isThisInLocalFun: Boolean = false): IrExpression {
-        // If the original is a "this" in a local function and original.type is the same as castType,
-        // we still want to keep the cast. See kt-42517
-        if (original.type == castType && !isThisInLocalFun) return original
+    private fun implicitCastOrExpression(original: IrExpression, castType: ConeKotlinType): IrExpression {
+        return implicitCastOrExpression(original, castType.toIrType())
+    }
+
+    private fun implicitCastOrExpression(original: IrExpression, castType: FirTypeRef): IrExpression {
+        return implicitCastOrExpression(original, castType.toIrType())
+    }
+
+    private fun implicitCastOrExpression(original: IrExpression, castType: IrType): IrExpression {
+        return original.takeIf { it.type == castType } ?: implicitCast(original, castType)
+    }
+
+    private fun implicitCast(original: IrExpression, castType: IrType): IrExpression {
         return IrTypeOperatorCallImpl(
             original.startOffset,
             original.endOffset,
@@ -438,14 +446,6 @@ class Fir2IrVisitor(
         )
     }
 
-    private fun implicitCastOrExpression(original: IrExpression, castType: ConeKotlinType): IrExpression {
-        return implicitCastOrExpression(original, castType.toIrType())
-    }
-
-    private fun implicitCastOrExpression(original: IrExpression, castType: FirTypeRef): IrExpression {
-        return implicitCastOrExpression(original, castType.toIrType())
-    }
-
     private fun ConeKotlinType.doesContainReferencedSymbolInScope(
         referencedSymbol: AbstractFirBasedSymbol<*>, name: Name
     ): Boolean {
@@ -466,7 +466,8 @@ class Fir2IrVisitor(
     private fun convertToImplicitCastExpression(
         expressionWithSmartcast: FirExpressionWithSmartcast, calleeReference: FirReference
     ): IrExpression {
-        val value = convertToIrExpression(expressionWithSmartcast.originalExpression)
+        val originalExpression = expressionWithSmartcast.originalExpression
+        val value = convertToIrExpression(originalExpression)
         val castTypeRef = expressionWithSmartcast.typeRef
         if (calleeReference !is FirResolvedNamedReference) {
             return implicitCastOrExpression(value, castTypeRef)
@@ -488,9 +489,15 @@ class Fir2IrVisitor(
                 }
             }
         }
-        val isLocalFun = ((value as? IrGetValue)?.symbol?.owner?.parent as? IrFunction)?.visibility == DescriptorVisibilities.LOCAL
-        return implicitCastOrExpression(value, castTypeRef.toIrType(),
-                                        isLocalFun && expressionWithSmartcast.originalExpression is FirThisReceiverExpression)
+        return if (originalExpression is FirThisReceiverExpression &&
+            originalExpression.calleeReference.boundSymbol is FirAnonymousFunctionSymbol
+        ) {
+            // If the original is a "this" in a local function and original.type is the same as castType,
+            // we still want to keep the cast. See kt-42517
+            implicitCast(value, castTypeRef.toIrType())
+        } else {
+            implicitCastOrExpression(value, castTypeRef.toIrType())
+        }
     }
 
     override fun visitExpressionWithSmartcast(expressionWithSmartcast: FirExpressionWithSmartcast, data: Any?): IrElement {