KT-18979 Add val to proper place for 'Add val/var' intent

idea/src/org/jetbrains/kotlin/idea/intentions/AddValVarToConstructorParameterAction.kt

@@ -46,7 +46,7 @@ interface AddValVarToConstructorParameterAction {
     fun invoke(element: KtParameter, editor: Editor?) {
         val project = element.project
 
-        element.addAfter(KtPsiFactory(project).createValKeyword(), null)
+        element.addBefore(KtPsiFactory(project).createValKeyword(), element.nameIdentifier)
 
         if (editor == null) return
 

idea/testData/quickfix/addValVar/addValAfterVarArg.kt

@@ -0,0 +1,4 @@
+// "Add val/var to parameter 'x'" "true"
+class Foo(vararg <caret>x: Int, val y: Int) {
+
+}

idea/testData/quickfix/addValVar/addValAfterVarArg.kt.after

@@ -0,0 +1,4 @@
+// "Add val/var to parameter 'x'" "true"
+class Foo(vararg val<caret> x: Int, val y: Int) {
+
+}

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

@@ -793,6 +793,12 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             doTest(fileName);
         }
 
+        @TestMetadata("addValAfterVarArg.kt")
+        public void testAddValAfterVarArg() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/addValVar/addValAfterVarArg.kt");
+            doTest(fileName);
+        }
+
         public void testAllFilesPresentInAddValVar() throws Exception {
             KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/quickfix/addValVar"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), TargetBackend.ANY, true);
         }