backing field migration fixes

idea/src/org/jetbrains/kotlin/idea/inspections/KotlinCleanupInspection.kt

@@ -89,7 +89,8 @@ public class KotlinCleanupInspection(): LocalInspectionTool(), CleanupLocalInspe
             Errors.USELESS_ELVIS,
             ErrorsJvm.POSITIONED_VALUE_ARGUMENT_FOR_JAVA_ANNOTATION,
             Errors.DEPRECATED_SYMBOL_WITH_MESSAGE,
-            Errors.ACCESS_TO_PRIVATE_TOP_LEVEL_FROM_ANOTHER_FILE
+            Errors.ACCESS_TO_PRIVATE_TOP_LEVEL_FROM_ANOTHER_FILE,
+            Errors.BACKING_FIELD_SYNTAX_DEPRECATED
     )
 
     private fun Diagnostic.isObsoleteLabel(): Boolean {

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

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2010-2015 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.quickfix
+
+import com.intellij.codeInsight.intention.IntentionAction
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.project.Project
+import org.jetbrains.kotlin.diagnostics.Diagnostic
+import org.jetbrains.kotlin.psi.JetFile
+import org.jetbrains.kotlin.psi.JetNameReferenceExpression
+import org.jetbrains.kotlin.psi.JetPsiFactory
+
+public class MigrateBackingFieldSyntaxFix(expr: JetNameReferenceExpression)
+    : JetIntentionAction<JetNameReferenceExpression>(expr), CleanupFix {
+    override fun invoke(project: Project, editor: Editor?, file: JetFile) {
+        val replacement = JetPsiFactory(project).createExpression("field")
+        element.replace(replacement)
+    }
+
+    override fun getFamilyName(): String = "Migrate backing field syntax"
+    override fun getText(): String = getFamilyName()
+
+    companion object : JetSingleIntentionActionFactory() {
+        override fun createAction(diagnostic: Diagnostic): IntentionAction? {
+            val element = diagnostic.psiElement as? JetNameReferenceExpression ?: return null
+            return MigrateBackingFieldSyntaxFix(element)
+        }
+    }
+}
+
+public class MigrateBackingFieldUsageFix(expr: JetNameReferenceExpression)
+    : JetIntentionAction<JetNameReferenceExpression>(expr) {
+    override fun invoke(project: Project, editor: Editor?, file: JetFile) {
+        val replacement = JetPsiFactory(project).createExpression(element.text.substring(1))
+        element.replace(replacement)
+    }
+
+    override fun getFamilyName(): String = "Replace with property access"
+    override fun getText(): String = getFamilyName()
+
+    companion object : JetSingleIntentionActionFactory() {
+        override fun createAction(diagnostic: Diagnostic): IntentionAction? {
+            val element = diagnostic.psiElement as? JetNameReferenceExpression ?: return null
+            if (element.text.length() > 1) {
+                return MigrateBackingFieldUsageFix(element)
+            }
+            return null
+        }
+    }
+}

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

@@ -319,5 +319,8 @@ public class QuickFixRegistrar : QuickFixContributor {
 
         UPPER_BOUND_VIOLATED.registerFactory(AddGenericUpperBoundFix.Factory)
         TYPE_INFERENCE_UPPER_BOUND_VIOLATED.registerFactory(AddGenericUpperBoundFix.Factory)
+
+        BACKING_FIELD_SYNTAX_DEPRECATED.registerFactory(MigrateBackingFieldSyntaxFix)
+        BACKING_FIELD_USAGE_DEPRECATED.registerFactory(MigrateBackingFieldUsageFix)
     }
 }

idea/testData/inspections/cleanup/cleanup.kt

@@ -35,3 +35,9 @@ fun unnecessaryCast(x: String) = x as String
 fun unnecessaryElvis(x: String) = x ?: ""
 
 @JavaAnn(1, "abc") class MyClass
+
+class Foo {
+    var x: Int = 0
+        get = $x
+        set(value) { $x = value }
+}

idea/testData/inspections/cleanup/cleanup.kt.after

@@ -34,3 +34,9 @@ fun unnecessaryCast(x: String) = x
 fun unnecessaryElvis(x: String) = x
 
 @JavaAnn(1, arg1 = "abc") class MyClass
+
+class Foo {
+    var x: Int = 0
+        get = field
+        set(value) { field = value }
+}

idea/testData/quickfix/migration/backingFieldSyntax/accessor.kt

@@ -0,0 +1,7 @@
+// "Migrate backing field syntax" "true"
+
+class Foo {
+    var a: Int = 0
+        get() = 0
+        set(v) { $<caret>a = v }
+}

idea/testData/quickfix/migration/backingFieldSyntax/accessor.kt.after

@@ -0,0 +1,7 @@
+// "Migrate backing field syntax" "true"
+
+class Foo {
+    var a: Int = 0
+        get() = 0
+        set(v) { field = v }
+}

idea/testData/quickfix/migration/backingFieldSyntax/usage.kt

@@ -0,0 +1,7 @@
+// "Replace with property access" "true"
+
+class A {
+    var foo: Int = 0
+
+    fun bar() = $f<caret>oo
+}

idea/testData/quickfix/migration/backingFieldSyntax/usage.kt.after

@@ -0,0 +1,7 @@
+// "Replace with property access" "true"
+
+class A {
+    var foo: Int = 0
+
+    fun bar() = foo
+}

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

@@ -4031,6 +4031,27 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/quickfix/migration"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), true);
         }
 
+        @TestMetadata("idea/testData/quickfix/migration/backingFieldSyntax")
+        @TestDataPath("$PROJECT_ROOT")
+        @RunWith(JUnit3RunnerWithInners.class)
+        public static class BackingFieldSyntax extends AbstractQuickFixTest {
+            @TestMetadata("accessor.kt")
+            public void testAccessor() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/quickfix/migration/backingFieldSyntax/accessor.kt");
+                doTest(fileName);
+            }
+
+            public void testAllFilesPresentInBackingFieldSyntax() throws Exception {
+                JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/quickfix/migration/backingFieldSyntax"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), true);
+            }
+
+            @TestMetadata("usage.kt")
+            public void testUsage() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/quickfix/migration/backingFieldSyntax/usage.kt");
+                doTest(fileName);
+            }
+        }
+
         @TestMetadata("idea/testData/quickfix/migration/conflictingExtension")
         @TestDataPath("$PROJECT_ROOT")
         @RunWith(JUnit3RunnerWithInners.class)