Add new line after modifier list if last child is comment

#KT-30804 Fixed

compiler/psi/src/org/jetbrains/kotlin/psi/addRemoveModifier.kt

@@ -22,6 +22,7 @@ import com.intellij.psi.PsiWhiteSpace
 import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
 import org.jetbrains.kotlin.lexer.KtTokens.*
 import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.psiUtil.getNextSiblingIgnoringWhitespace
 import org.jetbrains.kotlin.psi.psiUtil.siblings
 
 private fun KtModifierListOwner.addModifierList(newModifierList: KtModifierList): KtModifierList {
@@ -119,6 +120,12 @@ fun removeModifier(owner: KtModifierListOwner, modifier: KtModifierKeywordToken)
         it.getModifier(modifier)?.delete()
         if (it.firstChild == null) {
             it.delete()
+            return
+        }
+
+        val lastChild = it.lastChild
+        if (lastChild is PsiComment) {
+            it.addAfter(KtPsiFactory(owner).createNewLine(), lastChild)
         }
     }
 }

idea/src/org/jetbrains/kotlin/idea/quickfix/RemoveModifierFix.kt

@@ -49,18 +49,14 @@ class RemoveModifierFix(
 
     override fun getText() = text
 
-    override fun isAvailableImpl(project: Project, editor: Editor?, file: PsiFile) = (element?.hasModifier(modifier) ?: false)
+    override fun isAvailableImpl(project: Project, editor: Editor?, file: PsiFile) = element?.hasModifier(modifier) == true
 
     override fun invokeImpl(project: Project, editor: Editor?, file: PsiFile) {
         invoke()
     }
 
     fun invoke() {
-        val element = element ?: return
-        //TODO: without this copy&replace we get bad formatting on removing last modifier
-        val newElement = element.copy() as KtModifierListOwner
-        newElement.removeModifier(modifier)
-        element.replace(newElement)
+        element?.removeModifier(modifier)
     }
 
     companion object {

idea/testData/quickfix/modifiers/removeRedundantModifier3.kt.after

@@ -4,5 +4,5 @@ abstract class B() {
 }
 
 abstract class A() : B() {
-    abstract override <caret>fun foo()
+    abstract override<caret> fun foo()
 }

idea/testData/quickfix/modifiers/withAnnotationAndBlockComment.kt

@@ -0,0 +1,5 @@
+// "Remove 'final' modifier" "true"
+
+@Deprecated("")
+/* some comment */
+final<caret> val x: Int = 42

idea/testData/quickfix/modifiers/withAnnotationAndBlockComment.kt.after

@@ -0,0 +1,5 @@
+// "Remove 'final' modifier" "true"
+
+@Deprecated("")
+/* some comment */
+val x: Int = 42

idea/testData/quickfix/modifiers/withAnnotationAndEolComment.kt

@@ -0,0 +1,4 @@
+// "Remove 'final' modifier" "true"
+
+@Deprecated("") //some comment
+final<caret> val x: Int = 42

idea/testData/quickfix/modifiers/withAnnotationAndEolComment.kt.after

@@ -0,0 +1,4 @@
+// "Remove 'final' modifier" "true"
+
+@Deprecated("") //some comment
+val x: Int = 42

idea/testData/quickfix/modifiers/withAnnotationAndEolComment2.kt

@@ -0,0 +1,6 @@
+// "Remove 'final' modifier" "true"
+
+class A() {
+    @Deprecated("") // wd
+    final<caret> constructor(i: Int): this()
+}

idea/testData/quickfix/modifiers/withAnnotationAndEolComment2.kt.after

@@ -0,0 +1,6 @@
+// "Remove 'final' modifier" "true"
+
+class A() {
+    @Deprecated("") // wd
+    constructor(i: Int): this()
+}

idea/testData/quickfix/modifiers/withAnnotationAndEolComment3.kt

@@ -0,0 +1,6 @@
+// "Remove 'final' modifier" "true"
+
+class A @Deprecated("") // ds
+final<caret> constructor() {
+
+}

idea/testData/quickfix/modifiers/withAnnotationAndEolComment3.kt.after

@@ -0,0 +1,6 @@
+// "Remove 'final' modifier" "true"
+
+class A @Deprecated("") // ds
+constructor() {
+
+}

idea/testData/quickfix/redundantLateinit/simple.kt.after

@@ -1,5 +1,5 @@
 // "Remove 'lateinit' modifier" "true"
 
 class Test {
-    private <caret>var foo: String = ""
+    private<caret> var foo: String = ""
 }

idea/testData/quickfix/typeProjection/removeRedundantProjection1.kt

@@ -3,6 +3,6 @@ class Foo<out T> {
     val x = 0
 }
 
-fun bar(x : Foo< out<caret>  Any>) {
+fun bar(x : Foo<out<caret>  Any>) {
 
 }

idea/testData/quickfix/typeProjection/removeRedundantProjection2.kt

@@ -3,6 +3,6 @@ class Foo<in T> {
     val x = 0
 }
 
-fun bar(x : Foo< in<caret>  Any>) {
+fun bar(x : Foo<in<caret>  Any>) {
 
 }

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java

@@ -8622,6 +8622,26 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             runTest("idea/testData/quickfix/modifiers/visibilityModiferParameter.kt");
         }
 
+        @TestMetadata("withAnnotationAndBlockComment.kt")
+        public void testWithAnnotationAndBlockComment() throws Exception {
+            runTest("idea/testData/quickfix/modifiers/withAnnotationAndBlockComment.kt");
+        }
+
+        @TestMetadata("withAnnotationAndEolComment.kt")
+        public void testWithAnnotationAndEolComment() throws Exception {
+            runTest("idea/testData/quickfix/modifiers/withAnnotationAndEolComment.kt");
+        }
+
+        @TestMetadata("withAnnotationAndEolComment2.kt")
+        public void testWithAnnotationAndEolComment2() throws Exception {
+            runTest("idea/testData/quickfix/modifiers/withAnnotationAndEolComment2.kt");
+        }
+
+        @TestMetadata("withAnnotationAndEolComment3.kt")
+        public void testWithAnnotationAndEolComment3() throws Exception {
+            runTest("idea/testData/quickfix/modifiers/withAnnotationAndEolComment3.kt");
+        }
+
         @TestMetadata("idea/testData/quickfix/modifiers/addOpenToClassDeclaration")
         @TestDataPath("$PROJECT_ROOT")
         @RunWith(JUnit3RunnerWithInners.class)