[FIR] Remove the redundant backing field check

This commit fixes a failing visibility check
(FirSymbolByPsiTestGenerated.testBackingField) for the backing field.

Merge-request: KT-MR-6389
Merged-by: Nikolay Lunyak <Nikolay.Lunyak@jetbrains.com>

analysis/analysis-api-fe10/tests-gen/org/jetbrains/kotlin/analysis/api/fe10/test/cases/generated/cases/symbols/Fe10IdeNormalAnalysisSourceModuleSymbolByPsiTestGenerated.java

@@ -124,6 +124,12 @@ public class Fe10IdeNormalAnalysisSourceModuleSymbolByPsiTestGenerated extends A
         runTest("analysis/analysis-api/testData/symbols/symbolByPsi/enumValueMember.kt");
     }
 
+    @Test
+    @TestMetadata("explicitBackingField.kt")
+    public void testExplicitBackingField() throws Exception {
+        runTest("analysis/analysis-api/testData/symbols/symbolByPsi/explicitBackingField.kt");
+    }
+
     @Test
     @TestMetadata("extensionFunction.kt")
     public void testExtensionFunction() throws Exception {

analysis/analysis-api-fir/tests-gen/org/jetbrains/kotlin/analysis/api/fir/test/cases/generated/cases/symbols/FirIdeNormalAnalysisSourceModuleSymbolByPsiTestGenerated.java

@@ -124,6 +124,12 @@ public class FirIdeNormalAnalysisSourceModuleSymbolByPsiTestGenerated extends Ab
         runTest("analysis/analysis-api/testData/symbols/symbolByPsi/enumValueMember.kt");
     }
 
+    @Test
+    @TestMetadata("explicitBackingField.kt")
+    public void testExplicitBackingField() throws Exception {
+        runTest("analysis/analysis-api/testData/symbols/symbolByPsi/explicitBackingField.kt");
+    }
+
     @Test
     @TestMetadata("extensionFunction.kt")
     public void testExtensionFunction() throws Exception {

analysis/analysis-api-impl-base/tests/org/jetbrains/kotlin/analysis/api/impl/base/test/cases/symbols/AbstractSymbolByPsiTest.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.analysis.api.impl.base.test.cases.symbols
 
 import org.jetbrains.kotlin.analysis.api.KtAnalysisSession
+import org.jetbrains.kotlin.psi.KtBackingField
 import org.jetbrains.kotlin.psi.KtDeclaration
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.KtParameter
@@ -28,6 +29,7 @@ abstract class AbstractSymbolByPsiTest : AbstractSymbolTest() {
     private val KtDeclaration.isValidForSymbolCreation
         get() =
             when (this) {
+                is KtBackingField -> false
                 is KtParameter -> !this.isFunctionTypeParameter
                 else -> true
             }

analysis/analysis-api-standalone/tests-gen/org/jetbrains/kotlin/analysis/api/standalone/fir/test/cases/generated/cases/symbols/FirStandaloneNormalAnalysisSourceModuleSymbolByPsiTestGenerated.java

@@ -124,6 +124,12 @@ public class FirStandaloneNormalAnalysisSourceModuleSymbolByPsiTestGenerated ext
         runTest("analysis/analysis-api/testData/symbols/symbolByPsi/enumValueMember.kt");
     }
 
+    @Test
+    @TestMetadata("explicitBackingField.kt")
+    public void testExplicitBackingField() throws Exception {
+        runTest("analysis/analysis-api/testData/symbols/symbolByPsi/explicitBackingField.kt");
+    }
+
     @Test
     @TestMetadata("extensionFunction.kt")
     public void testExtensionFunction() throws Exception {

analysis/analysis-api/testData/symbols/symbolByPsi/explicitBackingField.kt

@@ -0,0 +1,6 @@
+var p: Int
+    field = "test"
+    get() = field.length
+    set(value) {
+        field = value.toString()
+    }

analysis/analysis-api/testData/symbols/symbolByPsi/explicitBackingField.pretty.txt

@@ -0,0 +1 @@
+var p: kotlin.Int

analysis/analysis-api/testData/symbols/symbolByPsi/explicitBackingField.txt

@@ -0,0 +1,91 @@
+KtPropertyGetterSymbol:
+  annotationsList: []
+  callableIdIfNonLocal: null
+  hasBody: true
+  hasStableParameterNames: true
+  isDefault: false
+  isExtension: false
+  isInline: false
+  isOverride: false
+  modality: FINAL
+  origin: SOURCE
+  receiverType: null
+  returnType: kotlin/Int
+  symbolKind: ACCESSOR
+  typeParameters: []
+  valueParameters: []
+  visibility: Public
+  getContainingModule: KtSourceModule "Sources of main"
+  deprecationStatus: null
+
+KtValueParameterSymbol:
+  annotationsList: []
+  callableIdIfNonLocal: null
+  generatedPrimaryConstructorProperty: null
+  hasDefaultValue: false
+  isExtension: false
+  isImplicitLambdaParameter: false
+  isVararg: false
+  name: value
+  origin: SOURCE
+  receiverType: null
+  returnType: kotlin/Int
+  symbolKind: LOCAL
+  typeParameters: []
+  getContainingModule: KtSourceModule "Sources of main"
+  deprecationStatus: null
+
+KtPropertySetterSymbol:
+  annotationsList: []
+  callableIdIfNonLocal: null
+  hasBody: true
+  hasStableParameterNames: true
+  isDefault: false
+  isExtension: false
+  isInline: false
+  isOverride: false
+  modality: FINAL
+  origin: SOURCE
+  parameter: KtValueParameterSymbol(value)
+  receiverType: null
+  returnType: kotlin/Unit
+  symbolKind: ACCESSOR
+  typeParameters: []
+  valueParameters: [
+    KtValueParameterSymbol(value)
+  ]
+  visibility: Public
+  getContainingModule: KtSourceModule "Sources of main"
+  deprecationStatus: null
+
+KtKotlinPropertySymbol:
+  annotationsList: []
+  callableIdIfNonLocal: /p
+  getter: KtPropertyGetterSymbol(<getter>)
+  hasBackingField: true
+  hasGetter: true
+  hasSetter: true
+  initializer: null
+  isConst: false
+  isDelegatedProperty: false
+  isExtension: false
+  isFromPrimaryConstructor: false
+  isLateInit: false
+  isOverride: false
+  isStatic: false
+  isVal: false
+  modality: FINAL
+  name: p
+  origin: SOURCE
+  receiverType: null
+  returnType: kotlin/Int
+  setter: KtPropertySetterSymbol(<setter>)
+  symbolKind: TOP_LEVEL
+  typeParameters: []
+  visibility: Public
+  getContainingModule: KtSourceModule "Sources of main"
+  deprecationStatus: null
+  getterDeprecationStatus: null
+  javaGetterName: getP
+  javaSetterName: setP
+  setterDeprecationStatus: null

analysis/low-level-api-fir/src/org/jetbrains/kotlin/analysis/low/level/api/fir/providers/LLFirProvider.kt

@@ -68,13 +68,12 @@ internal class LLFirProvider(
         symbol.fir.originalForSubstitutionOverride?.symbol?.let {
             return getFirCallableContainerFile(it)
         }
-        if (symbol is FirSyntheticPropertySymbol) {
-            val fir = symbol.fir
-            if (fir is FirSyntheticProperty) {
-                return getFirCallableContainerFile(fir.getter.delegate.symbol)
-            }
+        val fir = symbol.fir
+        return when {
+            symbol is FirBackingFieldSymbol -> getFirCallableContainerFile(symbol.fir.propertySymbol)
+            symbol is FirSyntheticPropertySymbol && fir is FirSyntheticProperty -> getFirCallableContainerFile(fir.getter.delegate.symbol)
+            else -> moduleComponents.cache.getContainerFirFile(symbol.fir)
         }
-        return moduleComponents.cache.getContainerFirFile(symbol.fir)
     }
 
     override fun getFirFilesByPackage(fqName: FqName): List<FirFile> = error("Should not be called in FIR IDE")

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

@@ -31,12 +31,6 @@ fun FirVisibilityChecker.isVisible(
         return isVisible(declaration.originalIfFakeOverride() as FirMemberDeclaration, callInfo, dispatchReceiverValue)
     }
 
-    // We won't resolve into the backing field
-    // in the first place, if it's not accessible.
-    if (declaration is FirBackingField) {
-        return true
-    }
-
     val useSiteFile = callInfo.containingFile
     val containingDeclarations = callInfo.containingDeclarations
     val session = callInfo.session