[K2] Support reporting of EXPECTED_ENUM_CONSTRUCTOR

^KT-59980 Fixed

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirExpectConsistencyChecker.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.fir.analysis.checkers.declaration
 
 import org.jetbrains.kotlin.KtFakeSourceElementKind
+import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
 import org.jetbrains.kotlin.diagnostics.reportOn
@@ -38,6 +39,9 @@ object FirExpectConsistencyChecker : FirBasicDeclarationChecker() {
         getConstructorDelegationCall(declaration)?.let { delegatedConstructor ->
             reporter.reportOn(delegatedConstructor.source, FirErrors.EXPECTED_CLASS_CONSTRUCTOR_DELEGATION_CALL, context)
         }
+        if (isProhibitedEnumConstructor(declaration, lastClass)) {
+            reporter.reportOn(source, FirErrors.EXPECTED_ENUM_CONSTRUCTOR, context)
+        }
 
         if (isProhibitedPrivateDeclaration(declaration)) {
             reporter.reportOn(source, FirErrors.EXPECTED_PRIVATE_DECLARATION, context)
@@ -65,6 +69,10 @@ object FirExpectConsistencyChecker : FirBasicDeclarationChecker() {
         return declaration !is FirConstructor && declaration !is FirPropertyAccessor && Visibilities.isPrivate(declaration.visibility)
     }
 
+    private fun isProhibitedEnumConstructor(declaration: FirMemberDeclaration, lastClass: FirClass?): Boolean {
+        return declaration is FirConstructor && lastClass?.classKind == ClassKind.ENUM_CLASS
+    }
+
     private fun isProhibitedDeclarationWithBody(declaration: FirMemberDeclaration): Boolean {
         return declaration is FirFunction && declaration.hasBody
     }

compiler/testData/diagnostics/tests/multiplatform/enum/constructorInHeaderEnum.fir.kt

@@ -1,12 +1,12 @@
 // MODULE: m1-common
 // FILE: common.kt
 
-<!NO_ACTUAL_FOR_EXPECT!>expect enum class En(x: Int) {
+<!NO_ACTUAL_FOR_EXPECT!>expect enum class En<!EXPECTED_ENUM_CONSTRUCTOR!>(x: Int)<!> {
     E1,
     E2(42),
     ;
 
-    constructor(s: String)
+    <!EXPECTED_ENUM_CONSTRUCTOR!>constructor(s: String)<!>
 }<!>
 
 <!NO_ACTUAL_FOR_EXPECT!>expect enum class En2 {