Inspection to warn on using == with array types #KT-13384 Fixed

idea/src/META-INF/plugin.xml

@@ -1329,6 +1329,11 @@
       <category>Kotlin</category>
     </intentionAction>
 
+    <intentionAction>
+      <className>org.jetbrains.kotlin.idea.intentions.ReplaceArrayEqualityOpWithArraysEqualsIntention</className>
+      <category>Kotlin</category>
+    </intentionAction>
+
     <localInspection implementationClass="org.jetbrains.kotlin.idea.intentions.ObjectLiteralToLambdaInspection"
                      displayName="Object literal can be converted to lambda"
                      groupName="Kotlin"
@@ -1746,6 +1751,14 @@
                      language="kotlin"
     />
 
+    <localInspection implementationClass="org.jetbrains.kotlin.idea.intentions.ReplaceArrayEqualityOpWithArraysEqualsInspection"
+                     displayName="Replace '==' with 'Arrays.equals'"
+                     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/ReplaceArrayEqualityOpWithArraysEqualsIntention.kt

@@ -0,0 +1,69 @@
+/*
+ * 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.descriptors.CallableDescriptor
+import org.jetbrains.kotlin.idea.caches.resolve.analyze
+import org.jetbrains.kotlin.idea.caches.resolve.resolveImportReference
+import org.jetbrains.kotlin.idea.inspections.IntentionBasedInspection
+import org.jetbrains.kotlin.idea.util.ImportInsertHelper
+import org.jetbrains.kotlin.js.descriptorUtils.nameIfStandardType
+import org.jetbrains.kotlin.lexer.KtTokens
+import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.psi.KtBinaryExpression
+import org.jetbrains.kotlin.psi.KtPsiFactory
+import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
+import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
+
+class ReplaceArrayEqualityOpWithArraysEqualsInspection :
+        IntentionBasedInspection<KtBinaryExpression>(ReplaceArrayEqualityOpWithArraysEqualsIntention::class)
+
+class ReplaceArrayEqualityOpWithArraysEqualsIntention : SelfTargetingOffsetIndependentIntention<KtBinaryExpression>(
+        KtBinaryExpression::class.java,
+        "Replace '==' with 'Arrays.equals'"
+) {
+    private val arrayName = Name.identifier("Array")
+
+    private fun ResolvedCall<out CallableDescriptor>.resolvedToArrayType() =
+            resultingDescriptor.returnType?.nameIfStandardType == arrayName
+
+    override fun applyTo(element: KtBinaryExpression, editor: Editor?) {
+        val project = element.project
+        val right = element.right ?: return
+        val left = element.left ?: return
+        val factory = KtPsiFactory(project)
+        val ktFile = element.getContainingKtFile()
+        ktFile.resolveImportReference(FqName("java.util.Arrays")).firstOrNull()?.let {
+            ImportInsertHelper.getInstance(project).importDescriptor(ktFile, it)
+        }
+        val expression = factory.createExpression("Arrays.equals(${left.text}, ${right.text})")
+        element.replace(expression)
+    }
+
+    override fun isApplicableTo(element: KtBinaryExpression): Boolean {
+        if (element.operationToken != KtTokens.EQEQ) return false
+        val right = element.right ?: return false
+        val left = element.left ?: return false
+        val rightResolvedCall = right.getResolvedCall(right.analyze()) ?: return false
+
+        if (!rightResolvedCall.resolvedToArrayType()) return false
+        val leftResolvedCall = left.getResolvedCall(left.analyze()) ?: return false
+        return leftResolvedCall.resolvedToArrayType()
+    }
+}