Add quick fix for deprecated 'class object' syntax

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

@@ -95,4 +95,4 @@ private val MODIFIERS_ORDER = listOf(PUBLIC_KEYWORD, PROTECTED_KEYWORD, PRIVATE_
                                      FINAL_KEYWORD, OPEN_KEYWORD, ABSTRACT_KEYWORD,
                                      OVERRIDE_KEYWORD,
                                      INNER_KEYWORD,
-                                     ANNOTATION_KEYWORD, ENUM_KEYWORD)
+                                     ANNOTATION_KEYWORD, ENUM_KEYWORD, DEFAULT_KEYWORD)

idea/idea-analysis/src/org/jetbrains/kotlin/idea/JetBundle.properties

@@ -179,6 +179,8 @@ options.kotlin.attribute.descriptor.smart.cast=Smart-cast value
 options.kotlin.attribute.descriptor.label=Label
 change.to.function.invocation=Change to function invocation
 migrate.sure=Replace sure() calls by !! in project
+migrate.class.object.to.default=Replace 'class' keyword with 'default' modifier
+migrate.class.object.to.default.family=Replace 'class' Keyword with 'default' Modifier
 remove.val.var.from.parameter=Remove ''{0}'' from parameter
 add.override.to.equals.hashCode.toString=Add 'override' to equals, hashCode, toString in project
 add.when.else.branch.action.family.name=Add Else Branch

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

@@ -0,0 +1,41 @@
+/*
+ * 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.openapi.editor.Editor
+import com.intellij.openapi.project.Project
+import org.jetbrains.kotlin.diagnostics.Diagnostic
+import org.jetbrains.kotlin.idea.JetBundle
+import org.jetbrains.kotlin.lexer.JetTokens
+import org.jetbrains.kotlin.psi.JetFile
+import org.jetbrains.kotlin.psi.JetObjectDeclaration
+
+public class ClassObjectToDefaultObjectFix(private val elem: JetObjectDeclaration) : JetIntentionAction<JetObjectDeclaration>(elem) {
+    override fun getText(): String = JetBundle.message("migrate.class.object.to.default")
+
+    override fun getFamilyName(): String = JetBundle.message("migrate.class.object.to.default.family")
+
+    override fun invoke(project: Project, editor: Editor, file: JetFile) {
+        elem.getClassKeyword()?.delete()
+        elem.addModifier(JetTokens.DEFAULT_KEYWORD)
+    }
+
+    default object Factory : JetSingleIntentionActionFactory() {
+        override fun createAction(diagnostic: Diagnostic) =
+                (diagnostic.getPsiElement() as? JetObjectDeclaration)?.let { ClassObjectToDefaultObjectFix(it) }
+    }
+}

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

@@ -294,5 +294,7 @@ public class QuickFixRegistrar {
         QuickFixes.factories.put(UNRESOLVED_REFERENCE, CreateClassFromTypeReferenceActionFactory.INSTANCE$);
         QuickFixes.factories.put(UNRESOLVED_REFERENCE, CreateClassFromReferenceExpressionActionFactory.INSTANCE$);
         QuickFixes.factories.put(UNRESOLVED_REFERENCE, CreateClassFromCallWithConstructorCalleeActionFactory.INSTANCE$);
+
+        QuickFixes.factories.put(DEPRECATED_CLASS_OBJECT_SYNTAX, ClassObjectToDefaultObjectFix.Factory);
     }
 }

idea/testData/quickfix/migration/afterClassObjectToDefaultSingle.kt

@@ -0,0 +1,7 @@
+// "Replace 'class' keyword with 'default' modifier" "true"
+
+class A {
+    public default object {
+
+    }
+}

idea/testData/quickfix/migration/beforeClassObjectToDefaultSingle.kt

@@ -0,0 +1,7 @@
+// "Replace 'class' keyword with 'default' modifier" "true"
+
+class A {
+    public class<caret> object {
+
+    }
+}

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

@@ -2850,6 +2850,12 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
         public void testAllFilesPresentInMigration() throws Exception {
             JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/quickfix/migration"), Pattern.compile("^before(\\w+)\\.kt$"), true);
         }
+
+        @TestMetadata("beforeClassObjectToDefaultSingle.kt")
+        public void testClassObjectToDefaultSingle() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/quickfix/migration/beforeClassObjectToDefaultSingle.kt");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("idea/testData/quickfix/modifiers")