FIR2IR: don't create Enum.entries in IR without the corresponding feature

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrConverter.kt

@@ -5,10 +5,13 @@
 
 package org.jetbrains.kotlin.fir.backend
 
+import org.jetbrains.kotlin.KtFakeSourceElementKind
 import org.jetbrains.kotlin.KtPsiSourceFileLinesMapping
 import org.jetbrains.kotlin.KtSourceFileLinesMappingFromLineStartOffsets
 import org.jetbrains.kotlin.backend.common.extensions.IrGenerationExtension
+import org.jetbrains.kotlin.builtins.StandardNames
 import org.jetbrains.kotlin.config.AnalysisFlags
+import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
@@ -24,6 +27,7 @@ import org.jetbrains.kotlin.fir.extensions.declarationGenerators
 import org.jetbrains.kotlin.fir.extensions.extensionService
 import org.jetbrains.kotlin.fir.extensions.generatedMembers
 import org.jetbrains.kotlin.fir.extensions.generatedNestedClassifiers
+import org.jetbrains.kotlin.fir.languageVersionSettings
 import org.jetbrains.kotlin.fir.packageFqName
 import org.jetbrains.kotlin.fir.psi
 import org.jetbrains.kotlin.fir.resolve.ScopeSession
@@ -164,7 +168,7 @@ class Fir2IrConverter(
         moduleFragment.files += irFile
     }
 
-    fun processClassHeaders(file: FirFile) {
+    private fun processClassHeaders(file: FirFile) {
         file.declarations.forEach {
             when (it) {
                 is FirRegularClass -> processClassAndNestedClassHeaders(it)
@@ -258,7 +262,7 @@ class Fir2IrConverter(
         return irClass
     }
 
-    fun bindFakeOverridesInFile(file: FirFile) {
+    private fun bindFakeOverridesInFile(file: FirFile) {
         val irFile = declarationStorage.getIrFile(file)
         for (irDeclaration in irFile.declarations) {
             if (irDeclaration is IrClass) {
@@ -355,9 +359,18 @@ class Fir2IrConverter(
                 )
             }
             is FirProperty -> {
-                declarationStorage.getOrCreateIrProperty(
-                    declaration, parent, isLocal = isLocal
-                )
+                if (declaration.source?.kind == KtFakeSourceElementKind.EnumGeneratedDeclaration &&
+                    declaration.name == StandardNames.ENUM_ENTRIES &&
+                    !session.languageVersionSettings.supportsFeature(LanguageFeature.EnumEntries)
+                ) {
+                    // Note: we have to do it, because backend without the feature
+                    // cannot process Enum.entries properly
+                    null
+                } else {
+                    declarationStorage.getOrCreateIrProperty(
+                        declaration, parent, isLocal = isLocal
+                    )
+                }
             }
             is FirField -> {
                 if (declaration.isSynthetic) {

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

@@ -37,6 +37,7 @@ import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.expressions.impl.*
 import org.jetbrains.kotlin.ir.symbols.*
 import org.jetbrains.kotlin.ir.types.*
+import org.jetbrains.kotlin.ir.types.impl.IrErrorTypeImpl
 import org.jetbrains.kotlin.ir.util.constructors
 import org.jetbrains.kotlin.ir.util.defaultType
 import org.jetbrains.kotlin.ir.util.parentClassOrNull
@@ -45,6 +46,7 @@ import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.name.SpecialNames
 import org.jetbrains.kotlin.psi.KtBinaryExpression
 import org.jetbrains.kotlin.psi.KtForExpression
+import org.jetbrains.kotlin.types.Variance
 import org.jetbrains.kotlin.util.OperatorNameConventions
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
@@ -311,7 +313,12 @@ class Fir2IrVisitor(
 
     override fun visitProperty(property: FirProperty, data: Any?): IrElement {
         if (property.isLocal) return visitLocalVariable(property)
-        val irProperty = declarationStorage.getCachedIrProperty(property)!!
+        val irProperty = declarationStorage.getCachedIrProperty(property)
+            ?: return IrErrorExpressionImpl(
+                UNDEFINED_OFFSET, UNDEFINED_OFFSET,
+                IrErrorTypeImpl(null, emptyList(), Variance.INVARIANT),
+                "Stub for Enum.entries"
+            )
         return conversionScope.withProperty(irProperty, property) {
             memberGenerator.convertPropertyContent(irProperty, property, containingClass = conversionScope.containerFirClass())
         }