Change Signature: Add/remove constructor keyword on primary constructor when changing modifier list

compiler/frontend/src/org/jetbrains/kotlin/psi/JetPrimaryConstructor.kt

@@ -17,9 +17,10 @@
 package org.jetbrains.kotlin.psi
 
 import com.intellij.lang.ASTNode
+import com.intellij.psi.PsiElement
 import org.jetbrains.kotlin.lexer.JetModifierKeywordToken
 import org.jetbrains.kotlin.lexer.JetTokens
-import org.jetbrains.kotlin.psi.addRemoveModifier.*
+import org.jetbrains.kotlin.psi.addRemoveModifier.addModifier
 import org.jetbrains.kotlin.psi.stubs.KotlinPlaceHolderStub
 import org.jetbrains.kotlin.psi.stubs.elements.JetStubElementTypes
 
@@ -31,16 +32,29 @@ public class JetPrimaryConstructor : JetConstructor<JetPrimaryConstructor> {
 
     override fun getContainingClassOrObject() = getParent() as JetClassOrObject
 
+    private fun getOrCreateConstructorKeyword(): PsiElement {
+        return getConstructorKeyword() ?: addBefore(JetPsiFactory(this).createConstructorKeyword(), valueParameterList!!)
+    }
+
     override fun addModifier(modifier: JetModifierKeywordToken) {
-        val modifierList = getModifierList()
+        val modifierList = modifierList
         if (modifierList != null) {
             addModifier(modifierList, modifier, JetTokens.PUBLIC_KEYWORD)
+            if (this.modifierList == null) {
+                getConstructorKeyword()?.delete()
+            }
         }
         else {
             if (modifier == JetTokens.PUBLIC_KEYWORD) return
-            val parameterList = getValueParameterList()!!
-            val newModifierList = JetPsiFactory(getProject()).createModifierList(modifier)
-            addBefore(newModifierList, parameterList)
+            val newModifierList = JetPsiFactory(this).createModifierList(modifier)
+            addBefore(newModifierList, getOrCreateConstructorKeyword())
+        }
+    }
+
+    override fun removeModifier(modifier: JetModifierKeywordToken) {
+        super.removeModifier(modifier)
+        if (modifierList == null) {
+            getConstructorKeyword()?.delete()
         }
     }
 

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

@@ -66,6 +66,9 @@ internal fun addModifier(modifierList: JetModifierList, modifier: JetModifierKey
     if (modifier == defaultVisibilityModifier) { // do not insert explicit 'internal' keyword (or 'public' for primary constructor)
         //TODO: code style option
         modifierToReplace?.delete()
+        if (modifierList.firstChild == null) {
+            modifierList.delete()
+        }
         return
     }
 
@@ -98,7 +101,12 @@ internal fun addModifier(modifierList: JetModifierList, modifier: JetModifierKey
 }
 
 internal fun removeModifier(owner: JetModifierListOwner, modifier: JetModifierKeywordToken) {
-    owner.getModifierList()?.getModifier(modifier)?.delete()
+    owner.getModifierList()?.let {
+        it.getModifier(modifier)?.delete()
+        if (it.firstChild == null) {
+            it.delete()
+        }
+    }
 }
 
 private val MODIFIERS_TO_REPLACE = mapOf(