[Analysis API FIR] KtFirValueParameterSymbol: fix expection

Effectively, it restores the fix from 2f8a64fff2

^KT-61422 Fixed

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/symbols/KtFirValueParameterSymbol.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
@@ -24,10 +24,8 @@ import org.jetbrains.kotlin.fir.correspondingProperty
 import org.jetbrains.kotlin.fir.declarations.FirFunction
 import org.jetbrains.kotlin.fir.renderWithType
 import org.jetbrains.kotlin.fir.symbols.impl.FirValueParameterSymbol
-import org.jetbrains.kotlin.fir.types.arrayElementType
-import org.jetbrains.kotlin.fir.utils.exceptions.withFirSymbolEntry
+import org.jetbrains.kotlin.fir.types.varargElementType
 import org.jetbrains.kotlin.name.Name
-import org.jetbrains.kotlin.utils.exceptions.errorWithAttachment
 
 internal class KtFirValueParameterSymbol(
     override val firSymbol: FirValueParameterSymbol,
@@ -51,12 +49,7 @@ internal class KtFirValueParameterSymbol(
     override val returnType by cached {
         val returnType = firSymbol.resolvedReturnType
         if (firSymbol.isVararg) {
-            // There SHOULD always be an array element type (even if it is an error type, e.g., unresolved).
-            val arrayElementType = returnType.arrayElementType()
-                ?: errorWithAttachment("No array element type for vararg value parameter") {
-                    withFirSymbolEntry("symbol", firSymbol)
-                }
-            builder.typeBuilder.buildKtType(arrayElementType)
+            builder.typeBuilder.buildKtType(returnType.varargElementType())
         } else {
             builder.typeBuilder.buildKtType(returnType)
         }