Idea: add quick fix for replacing usages of deprecated "INSTANCE$" field

idea/src/META-INF/plugin.xml

@@ -1240,6 +1240,14 @@
                      cleanupTool="true"
                      level="WARNING"/>
 
+    <localInspection implementationClass="org.jetbrains.kotlin.idea.inspections.DeprecatedObjectInstanceFieldReferenceInspection"
+                     displayName="Usage of deprecated 'INSTANCE$' field"
+                     groupName="Kotlin"
+                     language="JAVA"
+                     enabledByDefault="true"
+                     cleanupTool="true"
+                     level="WARNING"/>
+
     <referenceImporter implementation="org.jetbrains.kotlin.idea.quickfix.KotlinReferenceImporter"/>
 
     <fileType.fileViewProviderFactory filetype="KJSM" implementationClass="com.intellij.psi.ClassFileViewProviderFactory"/>

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

@@ -0,0 +1,65 @@
+/*
+ * 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.inspections
+
+import com.intellij.codeInspection.*
+import com.intellij.openapi.project.Project
+import com.intellij.psi.*
+import com.intellij.psi.codeStyle.JavaCodeStyleManager
+import org.jetbrains.kotlin.asJava.KotlinLightClass
+import org.jetbrains.kotlin.load.java.JvmAbi
+import org.jetbrains.kotlin.psi.JetObjectDeclaration
+
+public class DeprecatedObjectInstanceFieldReferenceInspection : LocalInspectionTool(), CleanupLocalInspectionTool {
+    override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
+        return object : JavaElementVisitor() {
+            override fun visitReferenceExpression(expression: PsiReferenceExpression) {
+                val resolvedTo = expression.reference?.resolve()
+                if (!(resolvedTo is PsiField && resolvedTo.name == JvmAbi.DEPRECATED_INSTANCE_FIELD)) return
+
+                val containingClass = resolvedTo.containingClass
+                if (containingClass !is KotlinLightClass || containingClass.getOrigin() !is JetObjectDeclaration) return
+
+                holder.registerProblem(
+                        expression, "Use of deprecated '${JvmAbi.DEPRECATED_INSTANCE_FIELD}' field",
+                        ProblemHighlightType.LIKE_DEPRECATED,
+                        DeprecatedObjectInstanceFieldReferenceFix()
+                )
+            }
+        }
+    }
+}
+
+public class DeprecatedObjectInstanceFieldReferenceFix : LocalQuickFix {
+    override fun getName(): String = "Replace with reference to '${JvmAbi.INSTANCE_FIELD}' field"
+    override fun getFamilyName(): String = name
+
+    override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
+        val reference = descriptor.psiElement.reference ?: return
+        val deprecatedField = reference.resolve() as? PsiField ?: return
+
+        val lightClassForObject = deprecatedField.containingClass as? KotlinLightClass ?: return
+        val correctField = lightClassForObject.findFieldByName(JvmAbi.INSTANCE_FIELD, false) ?: return
+
+        val newReference = reference.bindToElement(correctField)
+
+        val codeStyleManager = JavaCodeStyleManager.getInstance(project)
+        codeStyleManager.shortenClassReferences(newReference)
+        val javaFile = newReference.containingFile as? PsiJavaFile ?: return
+        codeStyleManager.removeRedundantImports(javaFile)
+    }
+}

idea/testData/quickfix/migration/deprecatedObjectInstanceField/.inspection

@@ -0,0 +1 @@
+org.jetbrains.kotlin.idea.inspections.DeprecatedObjectInstanceFieldReferenceInspection

idea/testData/quickfix/migration/deprecatedObjectInstanceField/basic.after.java

@@ -0,0 +1,8 @@
+// "Replace with reference to 'INSTANCE' field" "true"
+import a.A;
+
+class B {
+    void bar() {
+        A.INSTANCE.getName();
+    }
+}

idea/testData/quickfix/migration/deprecatedObjectInstanceField/basic.before.Main.java

@@ -0,0 +1,8 @@
+// "Replace with reference to 'INSTANCE' field" "true"
+import a.A;
+
+class B {
+    void bar() {
+        A.IN<caret>STANCE$.getName();
+    }
+}

idea/testData/quickfix/migration/deprecatedObjectInstanceField/basic.before.data.kt

@@ -0,0 +1,4 @@
+package a
+
+object A {
+}

idea/testData/quickfix/migration/deprecatedObjectInstanceField/staticImport.after.java

@@ -0,0 +1,8 @@
+// "Replace with reference to 'INSTANCE' field" "true"
+import a.A;
+
+class B {
+    void bar() {
+        A.INSTANCE.getName();
+    }
+}

idea/testData/quickfix/migration/deprecatedObjectInstanceField/staticImport.before.Main.java

@@ -0,0 +1,8 @@
+// "Replace with reference to 'INSTANCE' field" "true"
+import static a.A.INSTANCE$;
+
+class B {
+    void bar() {
+        IN<caret>STANCE$.getName();
+    }
+}

idea/testData/quickfix/migration/deprecatedObjectInstanceField/staticImport.before.data.kt

@@ -0,0 +1,5 @@
+package a
+
+object A {
+    val name: String = ""
+}

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

@@ -1063,6 +1063,27 @@ public class QuickFixMultiFileTestGenerated extends AbstractQuickFixMultiFileTes
             }
         }
 
+        @TestMetadata("idea/testData/quickfix/migration/deprecatedObjectInstanceField")
+        @TestDataPath("$PROJECT_ROOT")
+        @RunWith(JUnit3RunnerWithInners.class)
+        public static class DeprecatedObjectInstanceField extends AbstractQuickFixMultiFileTest {
+            public void testAllFilesPresentInDeprecatedObjectInstanceField() throws Exception {
+                JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/quickfix/migration/deprecatedObjectInstanceField"), Pattern.compile("^(\\w+)\\.before\\.Main\\.\\w+$"), true);
+            }
+
+            @TestMetadata("basic.before.Main.java")
+            public void testBasic() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/quickfix/migration/deprecatedObjectInstanceField/basic.before.Main.java");
+                doTestWithExtraFile(fileName);
+            }
+
+            @TestMetadata("staticImport.before.Main.java")
+            public void testStaticImport() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("idea/testData/quickfix/migration/deprecatedObjectInstanceField/staticImport.before.Main.java");
+                doTestWithExtraFile(fileName);
+            }
+        }
+
         @TestMetadata("idea/testData/quickfix/migration/deprecatedPackageFacade")
         @TestDataPath("$PROJECT_ROOT")
         @RunWith(JUnit3RunnerWithInners.class)