From 3c69a5efc89f69903227c8b77f6eb4d776acef74 Mon Sep 17 00:00:00 2001
From: Roman Golyshev <roman.golyshev@jetbrains.com>
Date: Mon, 13 Sep 2021 19:41:08 +0300
Subject: [PATCH] [FIR IDE] Handle `FirBackingField` in
 `buildVariableLikeSymbol`

Do a small refactoring of `buildBackingFieldSymbol`
---
 .../idea/frontend/api/fir/KtSymbolByFirBuilder.kt    | 12 +++++++-----
 .../idea/references/FirReferenceResolveHelper.kt     |  2 +-
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/KtSymbolByFirBuilder.kt b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/KtSymbolByFirBuilder.kt
index ac52aac9bc7..63beb3dfc51 100644
--- a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/KtSymbolByFirBuilder.kt
+++ b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/KtSymbolByFirBuilder.kt
@@ -54,7 +54,7 @@ internal class KtSymbolByFirBuilder private constructor(
     val withReadOnlyCaching: Boolean,
     private val symbolsCache: BuilderCache<FirDeclaration, KtSymbol>,
     private val filesCache: BuilderCache<FirFile, KtFileSymbol>,
-    private val backingFieldCache: BuilderCache<FirBackingFieldSymbol, KtBackingFieldSymbol>,
+    private val backingFieldCache: BuilderCache<FirBackingField, KtBackingFieldSymbol>,
     private val typesCache: BuilderCache<ConeKotlinType, KtType>,
 ) : ValidityTokenOwner {
     private val resolveState by weakRef(resolveState)
@@ -244,7 +244,9 @@ internal class KtSymbolByFirBuilder private constructor(
                 is FirValueParameter -> buildValueParameterSymbol(fir)
                 is FirField -> buildFieldSymbol(fir)
                 is FirEnumEntry -> buildEnumEntrySymbol(fir) // TODO enum entry should not be callable
-                else -> throwUnexpectedElementError(fir)
+                is FirBackingField -> buildBackingFieldSymbol(fir)
+
+                is FirErrorProperty -> throwUnexpectedElementError(fir)
             }
         }
 
@@ -289,14 +291,14 @@ internal class KtSymbolByFirBuilder private constructor(
             return symbolsCache.cache(fir) { KtFirJavaFieldSymbol(fir, resolveState, token, this@KtSymbolByFirBuilder) }
         }
 
-        fun buildBackingFieldSymbol(fir: FirBackingFieldSymbol): KtFirBackingFieldSymbol {
+        fun buildBackingFieldSymbol(fir: FirBackingField): KtFirBackingFieldSymbol {
             return backingFieldCache.cache(fir) {
-                KtFirBackingFieldSymbol(fir.fir.propertySymbol.fir, resolveState, token, this@KtSymbolByFirBuilder)
+                KtFirBackingFieldSymbol(fir.propertySymbol.fir, resolveState, token, this@KtSymbolByFirBuilder)
             }
         }
 
         fun buildBackingFieldSymbolByProperty(fir: FirProperty): KtFirBackingFieldSymbol {
-            val backingFieldSymbol = fir.backingField?.symbol
+            val backingFieldSymbol = fir.backingField
                 ?: error("FirProperty backingField is null")
             return buildBackingFieldSymbol(backingFieldSymbol)
         }
diff --git a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/references/FirReferenceResolveHelper.kt b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/references/FirReferenceResolveHelper.kt
index 391d4e6da36..d4d2e0fa7ab 100644
--- a/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/references/FirReferenceResolveHelper.kt
+++ b/idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/references/FirReferenceResolveHelper.kt
@@ -83,7 +83,7 @@ internal object FirReferenceResolveHelper {
     fun FirReference.toTargetSymbol(session: FirSession, symbolBuilder: KtSymbolByFirBuilder): Collection<KtSymbol> {
         return when (this) {
             is FirBackingFieldReference -> {
-                listOfNotNull(symbolBuilder.variableLikeBuilder.buildBackingFieldSymbol(resolvedSymbol))
+                listOfNotNull(resolvedSymbol.fir.buildSymbol(symbolBuilder))
             }
             is FirResolvedNamedReference -> {
                 val fir = when (val symbol = resolvedSymbol) {