Implement inspection to remove @ from annotation argument #KT-9228 Fixed

(cherry picked from commit 543c6bc)

idea/src/META-INF/plugin.xml

@@ -1255,6 +1255,11 @@
       <category>Kotlin</category>
     </intentionAction>
 
+    <intentionAction>
+      <className>org.jetbrains.kotlin.idea.intentions.RemoveAtFromAnnotationArgumentIntention</className>
+      <category>Kotlin</category>
+    </intentionAction>
+
     <localInspection implementationClass="org.jetbrains.kotlin.idea.intentions.ObjectLiteralToLambdaInspection"
                      displayName="Object literal can be converted to lambda"
                      groupName="Kotlin"
@@ -1594,6 +1599,14 @@
                      language="kotlin"
     />
 
+    <localInspection implementationClass="org.jetbrains.kotlin.idea.intentions.RemoveAtFromAnnotationArgumentInspection"
+                     displayName="Unnecessary @"
+                     groupName="Kotlin"
+                     enabledByDefault="true"
+                     level="WARNING"
+                     language="kotlin"
+    />
+
     <referenceImporter implementation="org.jetbrains.kotlin.idea.quickfix.KotlinReferenceImporter"/>
 
     <fileType.fileViewProviderFactory filetype="KJSM" implementationClass="com.intellij.psi.ClassFileViewProviderFactory"/>

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

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2010-2016 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.idea.intentions
+
+import com.intellij.openapi.editor.Editor
+import org.jetbrains.kotlin.idea.inspections.IntentionBasedInspection
+import org.jetbrains.kotlin.psi.KtAnnotatedExpression
+import org.jetbrains.kotlin.psi.KtAnnotationEntry
+import org.jetbrains.kotlin.psi.KtPsiFactory
+
+class RemoveAtFromAnnotationArgumentInspection : IntentionBasedInspection<KtAnnotatedExpression>(RemoveAtFromAnnotationArgumentIntention())
+
+class RemoveAtFromAnnotationArgumentIntention : SelfTargetingOffsetIndependentIntention<KtAnnotatedExpression>(
+        KtAnnotatedExpression::class.java,
+        "Remove @ from annotation argument"
+) {
+    override fun isApplicableTo(element: KtAnnotatedExpression): Boolean {
+        var parent = element.parent
+        while (parent != null) {
+            if (parent is KtAnnotationEntry) return true
+            parent = parent.parent
+        }
+        return false
+    }
+
+    override fun applyTo(element: KtAnnotatedExpression, editor: Editor?) {
+        val noAt = KtPsiFactory(element.project).createExpression(element.text.replaceFirst("@", ""))
+        element.replace(noAt)
+    }
+}