"Override members": add semicolon between enum entry and function

#KT-31139 Fixed

idea/src/org/jetbrains/kotlin/idea/formatter/KotlinPreFormatProcessor.kt

@@ -68,8 +68,15 @@ private class Visitor(var range: TextRange) : KtTreeVisitorVoid() {
             if (lastEntry == null && classBody.containsToken(KtTokens.SEMICOLON)) return
 
             val semicolon = psiFactory.createSemicolon()
-            classBody.addAfter(semicolon, lastEntry)
-            delta += semicolon.textLength
+            delta += if (lastEntry != null) {
+                classBody.addAfter(semicolon, lastEntry)
+                semicolon.textLength
+            } else {
+                val newLine = psiFactory.createNewLine()
+                classBody.addAfter(semicolon, classBody.lBrace)
+                classBody.addAfter(psiFactory.createNewLine(), classBody.lBrace)
+                semicolon.textLength + newLine.textLength
+            }
         }
 
         range = TextRange(range.startOffset, range.endOffset + delta)

idea/testData/codeInsight/overrideImplement/enumClass.kt

@@ -0,0 +1 @@
+enum <caret>class Foo

idea/testData/codeInsight/overrideImplement/enumClass.kt.after

@@ -0,0 +1,7 @@
+enum class Foo {
+    ;
+
+    override fun toString(): String {
+        <selection><caret>return super.toString()</selection>
+    }
+}

idea/testData/codeInsight/overrideImplement/enumClass2.kt

@@ -0,0 +1,2 @@
+enum <caret>class Foo {
+}

idea/testData/codeInsight/overrideImplement/enumClass2.kt.after

@@ -0,0 +1,7 @@
+enum class Foo {
+    ;
+
+    override fun toString(): String {
+        <selection><caret>return super.toString()</selection>
+    }
+}

idea/testData/codeInsight/overrideImplement/enumClass3.kt

@@ -0,0 +1,3 @@
+enum <caret>class Foo {
+    A
+}

idea/testData/codeInsight/overrideImplement/enumClass3.kt.after

@@ -0,0 +1,7 @@
+enum class Foo {
+    A;
+
+    override fun toString(): String {
+        <selection><caret>return super.toString()</selection>
+    }
+}

idea/testData/codeInsight/overrideImplement/enumClass4.kt

@@ -0,0 +1,3 @@
+enum <caret>class Foo {
+    A;
+}

idea/testData/codeInsight/overrideImplement/enumClass4.kt.after

@@ -0,0 +1,7 @@
+enum class Foo {
+    A;
+
+    override fun toString(): String {
+        <selection><caret>return super.toString()</selection>
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/codeInsight/OverrideImplementTest.kt

@@ -313,4 +313,20 @@ class OverrideImplementTest : AbstractOverrideImplementTest() {
     fun testImplementFromClassName6() {
         doMultiImplementFileTest()
     }
+
+    fun testEnumClass() {
+        doOverrideFileTest("toString")
+    }
+
+    fun testEnumClass2() {
+        doOverrideFileTest("toString")
+    }
+
+    fun testEnumClass3() {
+        doOverrideFileTest("toString")
+    }
+
+    fun testEnumClass4() {
+        doOverrideFileTest("toString")
+    }
 }