Add inspections and quickfixes of redundant Json format instantiation

Resolves KT-45075

generators/build.gradle.kts

@@ -70,6 +70,7 @@ dependencies {
     testCompile(projectTests(":kotlin-noarg-compiler-plugin"))
     testCompile(projectTests(":kotlin-sam-with-receiver-compiler-plugin"))
     testCompile(projectTests(":kotlinx-serialization-compiler-plugin"))
+    testCompile(projectTests(":kotlinx-serialization-ide-plugin"))
     testCompile(projectTests(":plugins:fir:fir-plugin-prototype"))
     testCompile(projectTests(":idea:jvm-debugger:jvm-debugger-test"))
     testCompile(projectTests(":generators:test-generator"))

generators/tests/org/jetbrains/kotlin/generators/tests/GenerateTests.kt

@@ -196,6 +196,8 @@ import org.jetbrains.kotlin.tools.projectWizard.wizard.AbstractYamlNewWizardProj
 import org.jetbrains.kotlinx.serialization.AbstractSerializationIrBytecodeListingTest
 import org.jetbrains.kotlinx.serialization.AbstractSerializationPluginBytecodeListingTest
 import org.jetbrains.kotlinx.serialization.AbstractSerializationPluginDiagnosticTest
+import org.jetbrains.kotlinx.serialization.idea.AbstractSerializationPluginIdeDiagnosticTest
+import org.jetbrains.kotlinx.serialization.idea.AbstractSerializationQuickFixTest
 
 fun main(args: Array<String>) {
     System.setProperty("java.awt.headless", "true")
@@ -1795,6 +1797,18 @@ fun main(args: Array<String>) {
             }
         }
 
+        testGroup(
+            "plugins/kotlin-serialization/kotlin-serialization-ide/test",
+            "plugins/kotlin-serialization/kotlin-serialization-ide/testData"
+        ) {
+            testClass<AbstractSerializationPluginIdeDiagnosticTest> {
+                model("diagnostics")
+            }
+            testClass<AbstractSerializationQuickFixTest> {
+                model("quickfix", pattern = "^([\\w\\-_]+)\\.kt$", filenameStartsLowerCase = true)
+            }
+        }
+
         testGroup("plugins/fir/fir-plugin-prototype/tests", "plugins/fir/fir-plugin-prototype/testData") {
             testClass<AbstractFirAllOpenDiagnosticTest> {
                 model("")

generators/tests/org/jetbrains/kotlin/generators/tests/GenerateTests.kt.as41

@@ -162,6 +162,8 @@ import org.jetbrains.kotlin.test.TargetBackend
 import org.jetbrains.kotlinx.serialization.AbstractSerializationPluginBytecodeListingTest
 import org.jetbrains.kotlinx.serialization.AbstractSerializationPluginDiagnosticTest
 import org.jetbrains.kotlinx.serialization.AbstractSerializationIrBytecodeListingTest
+import org.jetbrains.kotlinx.serialization.idea.AbstractSerializationPluginIdeDiagnosticTest
+import org.jetbrains.kotlinx.serialization.idea.AbstractSerializationQuickFixTest
 
 fun main(args: Array<String>) {
     System.setProperty("java.awt.headless", "true")
@@ -1220,6 +1222,18 @@ fun main(args: Array<String>) {
                 model("codegen")
             }
         }
+
+        testGroup(
+            "plugins/kotlin-serialization/kotlin-serialization-ide/test",
+            "plugins/kotlin-serialization/kotlin-serialization-ide/testData"
+        ) {
+            testClass<AbstractSerializationPluginIdeDiagnosticTest> {
+                model("diagnostics")
+            }
+            testClass<AbstractSerializationQuickFixTest> {
+                model("quickfix", pattern = "^([\\w\\-_]+)\\.kt$", filenameStartsLowerCase = true)
+            }
+        }
     /*
         testGroup("plugins/android-extensions/android-extensions-idea/tests", "plugins/android-extensions/android-extensions-idea/testData") {
             testClass<AbstractAndroidCompletionTest> {

generators/tests/org/jetbrains/kotlin/generators/tests/GenerateTests.kt.as42

@@ -159,6 +159,8 @@ import org.jetbrains.kotlin.test.TargetBackend
 import org.jetbrains.kotlinx.serialization.AbstractSerializationPluginBytecodeListingTest
 import org.jetbrains.kotlinx.serialization.AbstractSerializationPluginDiagnosticTest
 import org.jetbrains.kotlinx.serialization.AbstractSerializationIrBytecodeListingTest
+import org.jetbrains.kotlinx.serialization.idea.AbstractSerializationPluginIdeDiagnosticTest
+import org.jetbrains.kotlinx.serialization.idea.AbstractSerializationQuickFixTest
 
 fun main(args: Array<String>) {
     System.setProperty("java.awt.headless", "true")
@@ -1148,6 +1150,18 @@ fun main(args: Array<String>) {
             model("codegen")
         }
     }
+
+    testGroup(
+        "plugins/kotlin-serialization/kotlin-serialization-ide/test",
+        "plugins/kotlin-serialization/kotlin-serialization-ide/testData"
+    ) {
+        testClass<AbstractSerializationPluginIdeDiagnosticTest> {
+            model("diagnostics")
+        }
+        testClass<AbstractSerializationQuickFixTest> {
+            model("quickfix", pattern = "^([\\w\\-_]+)\\.kt$", filenameStartsLowerCase = true)
+        }
+    }
 /*
     testGroup("plugins/android-extensions/android-extensions-idea/tests", "plugins/android-extensions/android-extensions-idea/testData") {
         testClass<AbstractAndroidCompletionTest> {

plugins/kotlin-serialization/kotlin-serialization-compiler/build.gradle.kts

@@ -21,7 +21,7 @@ dependencies {
 
     testCompile(projectTests(":compiler:tests-common"))
     testCompile(commonDep("junit:junit"))
-    testImplementation("org.jetbrains.kotlinx:kotlinx-serialization-runtime-jvm:1.0-M1-1.4.0-rc") { isTransitive = false }
+    testImplementation("org.jetbrains.kotlinx:kotlinx-serialization-core:1.1.0")
 
     testRuntimeOnly(intellijCoreDep()) { includeJars("intellij-core") }
     testRuntimeOnly(intellijDep()) { includeJars("platform-concurrency") }

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/diagnostic/SerializationErrors.java

@@ -29,6 +29,8 @@ public interface SerializationErrors {
     DiagnosticFactory0<PsiElement> TRANSIENT_MISSING_INITIALIZER = DiagnosticFactory0.create(ERROR);
 
     DiagnosticFactory0<PsiElement> TRANSIENT_IS_REDUNDANT = DiagnosticFactory0.create(WARNING);
+    DiagnosticFactory0<PsiElement> JSON_FORMAT_REDUNDANT_DEFAULT = DiagnosticFactory0.create(WARNING);
+    DiagnosticFactory0<PsiElement> JSON_FORMAT_REDUNDANT = DiagnosticFactory0.create(WARNING);
 
     DiagnosticFactory0<PsiElement> INCORRECT_TRANSIENT = DiagnosticFactory0.create(WARNING);
 
@@ -42,4 +44,4 @@ public interface SerializationErrors {
                     .initializeFactoryNamesAndDefaultErrorMessages(SerializationErrors.class, SerializationPluginErrorsRendering.INSTANCE);
         }
     };
-}
+}

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/diagnostic/SerializationPluginErrorsRendering.kt

@@ -74,6 +74,14 @@ object SerializationPluginErrorsRendering : DefaultErrorMessages.Extension {
             SerializationErrors.TRANSIENT_IS_REDUNDANT,
             "Property does not have backing field which makes it non-serializable and therefore @Transient is redundant"
         )
+        MAP.put(
+            SerializationErrors.JSON_FORMAT_REDUNDANT_DEFAULT,
+            "Redundant creation of Json default format. Creating instances for each usage can be slow."
+        )
+        MAP.put(
+            SerializationErrors.JSON_FORMAT_REDUNDANT,
+            "Redundant creation of Json format. Creating instances for each usage can be slow."
+        )
         MAP.put(
             SerializationErrors.INCORRECT_TRANSIENT,
             "@kotlin.jvm.Transient does not affect @Serializable classes. Please use @kotlinx.serialization.Transient instead."
@@ -96,4 +104,4 @@ object SerializationPluginErrorsRendering : DefaultErrorMessages.Extension {
             Renderers.STRING
         )
     }
-}
+}

plugins/kotlin-serialization/kotlin-serialization-compiler/test/org/jetbrains/kotlinx/serialization/AbstractSerializationIrBytecodeListingTest.kt

@@ -13,7 +13,7 @@ import org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationComp
 import java.io.File
 
 abstract class AbstractSerializationIrBytecodeListingTest : AbstractAsmLikeInstructionListingTest() {
-    private val runtimeLibraryPath = getSerializationLibraryRuntimeJar()
+    private val coreLibraryPath = getSerializationCoreLibraryJar()
 
     override fun getExpectedTextFileName(wholeFile: File): String {
         return wholeFile.nameWithoutExtension + ".ir.txt"
@@ -23,6 +23,6 @@ abstract class AbstractSerializationIrBytecodeListingTest : AbstractAsmLikeInstr
 
     override fun setupEnvironment(environment: KotlinCoreEnvironment) {
         SerializationComponentRegistrar.registerExtensions(environment.project)
-        environment.updateClasspath(listOf(JvmClasspathRoot(runtimeLibraryPath!!)))
+        environment.updateClasspath(listOf(JvmClasspathRoot(coreLibraryPath!!)))
     }
 }

plugins/kotlin-serialization/kotlin-serialization-compiler/test/org/jetbrains/kotlinx/serialization/AbstractSerializationPluginBytecodeListingTest.kt

@@ -5,17 +5,16 @@
 
 package org.jetbrains.kotlinx.serialization
 
-import junit.framework.TestCase
 import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
 import org.jetbrains.kotlin.cli.jvm.config.JvmClasspathRoot
 import org.jetbrains.kotlin.codegen.AbstractAsmLikeInstructionListingTest
 import org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationComponentRegistrar
 
 abstract class AbstractSerializationPluginBytecodeListingTest : AbstractAsmLikeInstructionListingTest() {
-    private val runtimeLibraryPath = getSerializationLibraryRuntimeJar()
+    private val coreLibraryPath = getSerializationCoreLibraryJar()
 
     override fun setupEnvironment(environment: KotlinCoreEnvironment) {
         SerializationComponentRegistrar.registerExtensions(environment.project)
-        environment.updateClasspath(listOf(JvmClasspathRoot(runtimeLibraryPath!!)))
+        environment.updateClasspath(listOf(JvmClasspathRoot(coreLibraryPath!!)))
     }
-}
+}

plugins/kotlin-serialization/kotlin-serialization-compiler/test/org/jetbrains/kotlinx/serialization/AbstractSerializationPluginDiagnosticTest.kt

@@ -13,10 +13,10 @@ import org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationComp
 
 @OptIn(ObsoleteTestInfrastructure::class)
 abstract class AbstractSerializationPluginDiagnosticTest : AbstractDiagnosticsTest() {
-    private val runtimeLibraryPath = getSerializationLibraryRuntimeJar()
+    private val coreLibraryPath = getSerializationCoreLibraryJar()
 
     override fun setupEnvironment(environment: KotlinCoreEnvironment) {
         SerializationComponentRegistrar.registerExtensions(environment.project)
-        environment.updateClasspath(listOf(JvmClasspathRoot(runtimeLibraryPath!!)))
+        environment.updateClasspath(listOf(JvmClasspathRoot(coreLibraryPath!!)))
     }
 }

plugins/kotlin-serialization/kotlin-serialization-compiler/test/org/jetbrains/kotlinx/serialization/RuntimeSearch.kt

@@ -13,25 +13,25 @@ import java.io.File
 import kotlin.test.assertTrue
 
 class RuntimeLibraryInClasspathTest {
-    private val runtimeLibraryPath = getSerializationLibraryRuntimeJar()
+    private val coreLibraryPath = getSerializationCoreLibraryJar()
 
     @Test
     fun testRuntimeLibraryExists() {
         TestCase.assertNotNull(
             "kotlinx-serialization runtime library is not found. Make sure it is present in test classpath",
-            runtimeLibraryPath
+            coreLibraryPath
         )
     }
 
     @Test
     fun testRuntimeHasSufficientVersion() {
-        val version = VersionReader.getVersionsFromManifest(runtimeLibraryPath!!)
+        val version = VersionReader.getVersionsFromManifest(coreLibraryPath!!)
         assertTrue(version.currentCompilerMatchRequired(), "Runtime version too high")
         assertTrue(version.implementationVersionMatchSupported(), "Runtime version too low")
     }
 }
 
-internal fun getSerializationLibraryRuntimeJar(): File? = try {
+internal fun getSerializationCoreLibraryJar(): File? = try {
     PathUtil.getResourcePathForClass(Class.forName("kotlinx.serialization.KSerializer"))
 } catch (e: ClassNotFoundException) {
     null

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Basic.ir.txt

@@ -165,10 +165,6 @@ public final class ListOfUsers$$serializer : java/lang/Object, kotlinx/serializa
 
     public kotlinx.serialization.descriptors.SerialDescriptor getDescriptor()
 
-    public ListOfUsers patch(kotlinx.serialization.encoding.Decoder decoder, ListOfUsers old)
-
-    public java.lang.Object patch(kotlinx.serialization.encoding.Decoder decoder, java.lang.Object old)
-
     public void serialize(kotlinx.serialization.encoding.Encoder encoder, ListOfUsers value) {
         LABEL (L0)
           ALOAD (1)
@@ -276,18 +272,19 @@ public final class ListOfUsers : java/lang/Object {
     public void <init>(int seen1, java.util.List list, kotlinx.serialization.internal.SerializationConstructorMarker serializationConstructorMarker) {
         LABEL (L0)
         LINENUMBER (12)
-          ALOAD (0)
+          ICONST_1
-          INVOKESPECIAL (java/lang/Object, <init>, ()V)
+          ICONST_1
+          ILOAD (1)
+          IAND
+          IF_ICMPEQ (L1)
           ILOAD (1)
           ICONST_1
-          IAND
+          GETSTATIC (INSTANCE, LListOfUsers$$serializer;)
-          IFNE (L1)
+          INVOKEVIRTUAL (ListOfUsers$$serializer, getDescriptor, ()Lkotlinx/serialization/descriptors/SerialDescriptor;)
-          NEW
+          INVOKESTATIC (kotlinx/serialization/internal/PluginExceptionsKt, throwMissingFieldException, (IILkotlinx/serialization/descriptors/SerialDescriptor;)V)
-          DUP
-          LDC (list)
-          INVOKESPECIAL (kotlinx/serialization/MissingFieldException, <init>, (Ljava/lang/String;)V)
-          ATHROW
         LABEL (L1)
+          ALOAD (0)
+          INVOKESPECIAL (java/lang/Object, <init>, ()V)
           ALOAD (0)
           ALOAD (2)
           PUTFIELD (list, Ljava/util/List;)
@@ -453,10 +450,6 @@ public final class OptionalUser$$serializer : java/lang/Object, kotlinx/serializ
 
     public kotlinx.serialization.descriptors.SerialDescriptor getDescriptor()
 
-    public OptionalUser patch(kotlinx.serialization.encoding.Decoder decoder, OptionalUser old)
-
-    public java.lang.Object patch(kotlinx.serialization.encoding.Decoder decoder, java.lang.Object old)
-
     public void serialize(kotlinx.serialization.encoding.Encoder encoder, OptionalUser value) {
         LABEL (L0)
           ALOAD (1)
@@ -608,31 +601,41 @@ public final class OptionalUser : java/lang/Object {
     public void <init>(int seen1, User user, kotlinx.serialization.internal.SerializationConstructorMarker serializationConstructorMarker) {
         LABEL (L0)
         LINENUMBER (9)
+          ICONST_0
+          ILOAD (1)
+          IAND
+          IFEQ (L1)
+          ILOAD (1)
+          ICONST_0
+          GETSTATIC (INSTANCE, LOptionalUser$$serializer;)
+          INVOKEVIRTUAL (OptionalUser$$serializer, getDescriptor, ()Lkotlinx/serialization/descriptors/SerialDescriptor;)
+          INVOKESTATIC (kotlinx/serialization/internal/PluginExceptionsKt, throwMissingFieldException, (IILkotlinx/serialization/descriptors/SerialDescriptor;)V)
+        LABEL (L1)
           ALOAD (0)
           INVOKESPECIAL (java/lang/Object, <init>, ()V)
           ILOAD (1)
           ICONST_1
           IAND
-          IFNE (L1)
+          IFNE (L2)
           ALOAD (0)
-        LABEL (L2)
+        LABEL (L3)
         LINENUMBER (10)
           NEW
           DUP
           LDC ()
           LDC ()
           INVOKESPECIAL (User, <init>, (Ljava/lang/String;Ljava/lang/String;)V)
-        LABEL (L3)
+        LABEL (L4)
         LINENUMBER (9)
           PUTFIELD (user, LUser;)
-          GOTO (L4)
+          GOTO (L5)
-        LABEL (L1)
+        LABEL (L2)
           ALOAD (0)
           ALOAD (2)
           PUTFIELD (user, LUser;)
-        LABEL (L4)
-          RETURN
         LABEL (L5)
+          RETURN
+        LABEL (L6)
     }
 
     public void <init>() {
@@ -829,10 +832,6 @@ public final class User$$serializer : java/lang/Object, kotlinx/serialization/in
 
     public kotlinx.serialization.descriptors.SerialDescriptor getDescriptor()
 
-    public User patch(kotlinx.serialization.encoding.Decoder decoder, User old)
-
-    public java.lang.Object patch(kotlinx.serialization.encoding.Decoder decoder, java.lang.Object old)
-
     public void serialize(kotlinx.serialization.encoding.Encoder encoder, User value) {
         LABEL (L0)
           ALOAD (1)
@@ -948,36 +947,27 @@ public final class User : java/lang/Object {
     public void <init>(int seen1, java.lang.String firstName, java.lang.String lastName, kotlinx.serialization.internal.SerializationConstructorMarker serializationConstructorMarker) {
         LABEL (L0)
         LINENUMBER (6)
+          ICONST_3
+          ICONST_3
+          ILOAD (1)
+          IAND
+          IF_ICMPEQ (L1)
+          ILOAD (1)
+          ICONST_3
+          GETSTATIC (INSTANCE, LUser$$serializer;)
+          INVOKEVIRTUAL (User$$serializer, getDescriptor, ()Lkotlinx/serialization/descriptors/SerialDescriptor;)
+          INVOKESTATIC (kotlinx/serialization/internal/PluginExceptionsKt, throwMissingFieldException, (IILkotlinx/serialization/descriptors/SerialDescriptor;)V)
+        LABEL (L1)
           ALOAD (0)
           INVOKESPECIAL (java/lang/Object, <init>, ()V)
-          ILOAD (1)
-          ICONST_1
-          IAND
-          IFNE (L1)
-          NEW
-          DUP
-          LDC (firstName)
-          INVOKESPECIAL (kotlinx/serialization/MissingFieldException, <init>, (Ljava/lang/String;)V)
-          ATHROW
-        LABEL (L1)
           ALOAD (0)
           ALOAD (2)
           PUTFIELD (firstName, Ljava/lang/String;)
-          ILOAD (1)
-          ICONST_2
-          IAND
-          IFNE (L2)
-          NEW
-          DUP
-          LDC (lastName)
-          INVOKESPECIAL (kotlinx/serialization/MissingFieldException, <init>, (Ljava/lang/String;)V)
-          ATHROW
-        LABEL (L2)
           ALOAD (0)
           ALOAD (3)
           PUTFIELD (lastName, Ljava/lang/String;)
           RETURN
-        LABEL (L3)
+        LABEL (L2)
     }
 
     public final java.lang.String getFirstName()

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Basic.txt

@@ -144,10 +144,6 @@ public final class ListOfUsers$$serializer : java/lang/Object, kotlinx/serializa
 
     public kotlinx.serialization.descriptors.SerialDescriptor getDescriptor()
 
-    public ListOfUsers patch(kotlinx.serialization.encoding.Decoder decoder, ListOfUsers old)
-
-    public java.lang.Object patch(kotlinx.serialization.encoding.Decoder p0, java.lang.Object p1)
-
     public void serialize(kotlinx.serialization.encoding.Encoder encoder, ListOfUsers value) {
         LABEL (L0)
           ALOAD (1)
@@ -241,19 +237,20 @@ public final class ListOfUsers : java/lang/Object {
 
     public void <init>(int seen1, java.util.List list, kotlinx.serialization.internal.SerializationConstructorMarker serializationConstructorMarker) {
         LABEL (L0)
-          ALOAD (0)
+          ICONST_1
-          INVOKESPECIAL (java/lang/Object, <init>, ()V)
+          DUP
+          ILOAD (1)
+          IAND
+          IF_ICMPEQ (L1)
           ILOAD (1)
           ICONST_1
-          IAND
+          GETSTATIC (INSTANCE, LListOfUsers$$serializer;)
-          IFNE (L1)
-          NEW
-          DUP
-          LDC (list)
-          INVOKESPECIAL (kotlinx/serialization/MissingFieldException, <init>, (Ljava/lang/String;)V)
           CHECKCAST
-          ATHROW
+          INVOKEINTERFACE (kotlinx/serialization/KSerializer, getDescriptor, ()Lkotlinx/serialization/descriptors/SerialDescriptor;)
+          INVOKESTATIC (kotlinx/serialization/internal/PluginExceptionsKt, throwMissingFieldException, (IILkotlinx/serialization/descriptors/SerialDescriptor;)V)
         LABEL (L1)
+          ALOAD (0)
+          INVOKESPECIAL (java/lang/Object, <init>, ()V)
           ALOAD (0)
           ALOAD (2)
           PUTFIELD (list, Ljava/util/List;)
@@ -427,10 +424,6 @@ public final class OptionalUser$$serializer : java/lang/Object, kotlinx/serializ
 
     public kotlinx.serialization.descriptors.SerialDescriptor getDescriptor()
 
-    public OptionalUser patch(kotlinx.serialization.encoding.Decoder decoder, OptionalUser old)
-
-    public java.lang.Object patch(kotlinx.serialization.encoding.Decoder p0, java.lang.Object p1)
-
     public void serialize(kotlinx.serialization.encoding.Encoder encoder, OptionalUser value) {
         LABEL (L0)
           ALOAD (1)
@@ -553,19 +546,31 @@ public final class OptionalUser : java/lang/Object {
 
     public void <init>(int seen1, User user, kotlinx.serialization.internal.SerializationConstructorMarker serializationConstructorMarker) {
         LABEL (L0)
+          ICONST_0
+          DUP
+          ILOAD (1)
+          IAND
+          IF_ICMPEQ (L1)
+          ILOAD (1)
+          ICONST_0
+          GETSTATIC (INSTANCE, LOptionalUser$$serializer;)
+          CHECKCAST
+          INVOKEINTERFACE (kotlinx/serialization/KSerializer, getDescriptor, ()Lkotlinx/serialization/descriptors/SerialDescriptor;)
+          INVOKESTATIC (kotlinx/serialization/internal/PluginExceptionsKt, throwMissingFieldException, (IILkotlinx/serialization/descriptors/SerialDescriptor;)V)
+        LABEL (L1)
           ALOAD (0)
           INVOKESPECIAL (java/lang/Object, <init>, ()V)
           ILOAD (1)
           ICONST_1
           IAND
-          IFEQ (L1)
+          IFEQ (L2)
           ALOAD (0)
           ALOAD (2)
           PUTFIELD (user, LUser;)
-          GOTO (L2)
+          GOTO (L3)
-        LABEL (L1)
+        LABEL (L2)
           ALOAD (0)
-        LABEL (L3)
+        LABEL (L4)
         LINENUMBER (10)
           NEW
           DUP
@@ -573,9 +578,9 @@ public final class OptionalUser : java/lang/Object {
           LDC ()
           INVOKESPECIAL (User, <init>, (Ljava/lang/String;Ljava/lang/String;)V)
           PUTFIELD (user, LUser;)
-        LABEL (L2)
+        LABEL (L3)
           RETURN
-        LABEL (L4)
+        LABEL (L5)
     }
 
     public final User getUser()
@@ -781,10 +786,6 @@ public final class User$$serializer : java/lang/Object, kotlinx/serialization/in
 
     public kotlinx.serialization.descriptors.SerialDescriptor getDescriptor()
 
-    public User patch(kotlinx.serialization.encoding.Decoder decoder, User old)
-
-    public java.lang.Object patch(kotlinx.serialization.encoding.Decoder p0, java.lang.Object p1)
-
     public void serialize(kotlinx.serialization.encoding.Encoder encoder, User value) {
         LABEL (L0)
           ALOAD (1)
@@ -886,38 +887,28 @@ public final class User : java/lang/Object {
 
     public void <init>(int seen1, java.lang.String firstName, java.lang.String lastName, kotlinx.serialization.internal.SerializationConstructorMarker serializationConstructorMarker) {
         LABEL (L0)
+          ICONST_3
+          DUP
+          ILOAD (1)
+          IAND
+          IF_ICMPEQ (L1)
+          ILOAD (1)
+          ICONST_3
+          GETSTATIC (INSTANCE, LUser$$serializer;)
+          CHECKCAST
+          INVOKEINTERFACE (kotlinx/serialization/KSerializer, getDescriptor, ()Lkotlinx/serialization/descriptors/SerialDescriptor;)
+          INVOKESTATIC (kotlinx/serialization/internal/PluginExceptionsKt, throwMissingFieldException, (IILkotlinx/serialization/descriptors/SerialDescriptor;)V)
+        LABEL (L1)
           ALOAD (0)
           INVOKESPECIAL (java/lang/Object, <init>, ()V)
-          ILOAD (1)
-          ICONST_1
-          IAND
-          IFNE (L1)
-          NEW
-          DUP
-          LDC (firstName)
-          INVOKESPECIAL (kotlinx/serialization/MissingFieldException, <init>, (Ljava/lang/String;)V)
-          CHECKCAST
-          ATHROW
-        LABEL (L1)
           ALOAD (0)
           ALOAD (2)
           PUTFIELD (firstName, Ljava/lang/String;)
-          ILOAD (1)
-          ICONST_2
-          IAND
-          IFNE (L2)
-          NEW
-          DUP
-          LDC (lastName)
-          INVOKESPECIAL (kotlinx/serialization/MissingFieldException, <init>, (Ljava/lang/String;)V)
-          CHECKCAST
-          ATHROW
-        LABEL (L2)
           ALOAD (0)
           ALOAD (3)
           PUTFIELD (lastName, Ljava/lang/String;)
           RETURN
-        LABEL (L3)
+        LABEL (L2)
     }
 
     public final java.lang.String getFirstName()

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/DuplicateSerialName.txt

@@ -15,7 +15,6 @@ package
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): Derived
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: Derived): Derived
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: Derived): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         public open override /*1*/ /*fake_override*/ fun typeParametersSerializers(): kotlin.Array<kotlinx.serialization.KSerializer<*>>
@@ -45,7 +44,6 @@ package
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): Parent
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: Parent): Parent
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: Parent): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         public open override /*1*/ /*fake_override*/ fun typeParametersSerializers(): kotlin.Array<kotlinx.serialization.KSerializer<*>>

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/LazyRecursionBug.kt

@@ -1,4 +1,5 @@
 // This test enshures that analysis ends up without compiler exceptions
+// !DIAGNOSTICS: -EXPERIMENTAL_API_USAGE
 
 import kotlinx.serialization.*
 

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/LazyRecursionBug.txt

@@ -13,7 +13,6 @@ package
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): Digest
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: Digest): Digest
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: Digest): kotlin.Unit
         public final /*synthesized*/ fun serializer(): kotlinx.serialization.KSerializer<Digest>
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/NoSuitableCtorInParent.txt

@@ -16,7 +16,6 @@ package
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): Derived
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: Derived): Derived
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: Derived): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         public open override /*1*/ /*fake_override*/ fun typeParametersSerializers(): kotlin.Array<kotlinx.serialization.KSerializer<*>>

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/NonSerializable.txt

@@ -15,7 +15,6 @@ package
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): Basic
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: Basic): Basic
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: Basic): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         public open override /*1*/ /*fake_override*/ fun typeParametersSerializers(): kotlin.Array<kotlinx.serialization.KSerializer<*>>
@@ -45,7 +44,6 @@ package
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): Inside
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: Inside): Inside
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: Inside): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         public open override /*1*/ /*fake_override*/ fun typeParametersSerializers(): kotlin.Array<kotlinx.serialization.KSerializer<*>>
@@ -82,7 +80,6 @@ public final class NonSerializable {
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): WithImplicitType
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: WithImplicitType): WithImplicitType
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: WithImplicitType): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         public open override /*1*/ /*fake_override*/ fun typeParametersSerializers(): kotlin.Array<kotlinx.serialization.KSerializer<*>>

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/NullabilityIncompatible.txt

@@ -15,7 +15,6 @@ package
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): Foo
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: Foo): Foo
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: Foo): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         public open override /*1*/ /*fake_override*/ fun typeParametersSerializers(): kotlin.Array<kotlinx.serialization.KSerializer<*>>
@@ -51,7 +50,6 @@ public final class NopeNullableSerializer : kotlinx.serialization.KSerializer<No
     public open override /*1*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): Nope?
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: Nope?): Nope?
     public open override /*1*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: Nope?): kotlin.Nothing
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/ParamIsNotProperty.txt

@@ -15,7 +15,6 @@ package
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): Test
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: Test): Test
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: Test): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         public open override /*1*/ /*fake_override*/ fun typeParametersSerializers(): kotlin.Array<kotlinx.serialization.KSerializer<*>>

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/SerializableEnums.txt

@@ -6,7 +6,6 @@ public object EnumSerializer : kotlinx.serialization.KSerializer<ExplicitlyMarke
     public open override /*1*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): ExplicitlyMarkedEnumCustom
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: ExplicitlyMarkedEnumCustom): ExplicitlyMarkedEnumCustom
     public open override /*1*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: ExplicitlyMarkedEnumCustom): kotlin.Nothing
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
@@ -32,7 +31,6 @@ public object EnumSerializer : kotlinx.serialization.KSerializer<ExplicitlyMarke
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): EnumUsage
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: EnumUsage): EnumUsage
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: EnumUsage): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         public open override /*1*/ /*fake_override*/ fun typeParametersSerializers(): kotlin.Array<kotlinx.serialization.KSerializer<*>>
@@ -70,7 +68,6 @@ public object EnumSerializer : kotlinx.serialization.KSerializer<ExplicitlyMarke
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): ExplicitlyMarkedEnum
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: ExplicitlyMarkedEnum): ExplicitlyMarkedEnum
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: ExplicitlyMarkedEnum): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         public open override /*1*/ /*fake_override*/ fun typeParametersSerializers(): kotlin.Array<kotlinx.serialization.KSerializer<*>>

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/SerializerTypeCompatibleForSpecials.kt

@@ -1,3 +1,4 @@
+// !DIAGNOSTICS: -EXPERIMENTAL_API_USAGE
 // WITH_RUNTIME
 // SKIP_TXT
 
@@ -15,4 +16,4 @@ object BazSerializer: KSerializer<Baz>
 class Foo1(@Polymorphic val i: Baz)
 
 @Serializable
-class Foo2(val li: MutableList<@Serializable(with = BazSerializer::class) Baz>)
+class Foo2(val li: MutableList<@Serializable(with = BazSerializer::class) Baz>)

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/SerializerTypeIncompatible.kt

@@ -1,3 +1,4 @@
+// !DIAGNOSTICS: -EXPERIMENTAL_API_USAGE
 // WITH_RUNTIME
 // SKIP_TXT
 
@@ -32,4 +33,4 @@ class Foo5(@Serializable(with = BazSerializer::class) val i: <!SERIALIZER_TYPE_I
 class Foo6(@Serializable(with = NullableBazSerializer::class) val i: <!SERIALIZER_NULLABILITY_INCOMPATIBLE, SERIALIZER_TYPE_INCOMPATIBLE!>Bar<!>)
 
 @Serializable
-class Foo7(@Serializable(with = NullableBazSerializer::class) val i: <!SERIALIZER_TYPE_INCOMPATIBLE!>Bar?<!>)
+class Foo7(@Serializable(with = NullableBazSerializer::class) val i: <!SERIALIZER_TYPE_INCOMPATIBLE!>Bar?<!>)

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/diagnostics/Transients.txt

@@ -19,7 +19,6 @@ package
         public open override /*1*/ /*synthesized*/ fun deserialize(/*0*/ decoder: kotlinx.serialization.encoding.Decoder): WithTransients
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-        @kotlin.Deprecated(level = DeprecationLevel.ERROR, message = "Patch function is deprecated for removal since this functionality is no longer supported by serializer.Some formats may provide implementation-specific patching in their Decoders.") public open override /*1*/ /*fake_override*/ fun patch(/*0*/ decoder: kotlinx.serialization.encoding.Decoder, /*1*/ old: WithTransients): WithTransients
         public open override /*1*/ /*synthesized*/ fun serialize(/*0*/ encoder: kotlinx.serialization.encoding.Encoder, /*1*/ value: WithTransients): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
         public open override /*1*/ /*fake_override*/ fun typeParametersSerializers(): kotlin.Array<kotlinx.serialization.KSerializer<*>>

plugins/kotlin-serialization/kotlin-serialization-ide/build.gradle.kts

@@ -19,8 +19,24 @@ dependencies {
     excludeInAndroidStudio(rootProject) { compileOnly(intellijPluginDep("maven")) }
     compileOnly(intellijPluginDep("gradle"))
 
-    testCompileOnly(intellijDep())
+    testCompile(toolsJar())
-    testRuntimeOnly(intellijDep())
+    testCompile(projectTests(":idea"))
+    testCompile(projectTests(":compiler:tests-common"))
+    testCompile(projectTests(":idea:idea-test-framework"))
+    testCompile(project(":kotlin-test:kotlin-test-junit"))
+    testCompile(commonDep("junit:junit"))
+    testCompile(projectTests(":idea:idea-frontend-independent"))
+
+    testImplementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.1.0")
+
+    testRuntimeOnly(intellijCoreDep()) { includeJars("intellij-core") }
+
+    testRuntime(project(":allopen-ide-plugin"))
+    testRuntime(project(":plugins:parcelize:parcelize-ide"))
+    testRuntime(project(":sam-with-receiver-ide-plugin"))
+    testRuntime(project(":noarg-ide-plugin"))
+    testCompile(intellijDep())
+    testCompile(intellijPluginDep("java"))
 }
 
 sourceSets {
@@ -29,7 +45,8 @@ sourceSets {
 }
 
 runtimeJar()
+testsJar()
 
 projectTest(parallel = true) {
-
+    workingDir = rootDir
-}
+}

plugins/kotlin-serialization/kotlin-serialization-ide/resources/messages/KotlinSerializationBundle.properties

@@ -0,0 +1,2 @@
+extract.json.to.property=Extract Json format creation to property
+replace.with.default.json.format=Replace with default Json format instance

plugins/kotlin-serialization/kotlin-serialization-ide/src/org/jetbrains/kotlinx/serialization/compiler/diagnostic/JsonFormatRedundantDiagnostic.kt

@@ -0,0 +1,96 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlinx.serialization.compiler.diagnostic
+
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.name.FqName
+import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.resolve.calls.callUtil.getReceiverExpression
+import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
+import org.jetbrains.kotlin.resolve.calls.checkers.CallChecker
+import org.jetbrains.kotlin.resolve.calls.checkers.CallCheckerContext
+import org.jetbrains.kotlin.resolve.calls.model.DefaultValueArgument
+import org.jetbrains.kotlin.resolve.calls.model.ExpressionValueArgument
+import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
+import org.jetbrains.kotlin.resolve.calls.model.ResolvedValueArgument
+import org.jetbrains.kotlin.idea.imports.importableFqName
+import org.jetbrains.kotlin.idea.refactoring.fqName.fqName
+import org.jetbrains.kotlin.psi.KtNamedFunction
+import org.jetbrains.kotlin.psi.unpackFunctionLiteral
+import org.jetbrains.kotlin.resolve.BindingContext
+
+
+class JsonFormatRedundantDiagnostic : CallChecker {
+    private val jsonFqName = FqName("kotlinx.serialization.json.Json")
+    private val jsonDefaultFqName = FqName("kotlinx.serialization.json.Json.Default")
+    private val parameterNameFrom = Name.identifier("from")
+    private val parameterNameBuilderAction = Name.identifier("builderAction")
+
+    override fun check(resolvedCall: ResolvedCall<*>, reportOn: PsiElement, context: CallCheckerContext) {
+        val functionDescriptor = resolvedCall.resultingDescriptor as? SimpleFunctionDescriptor ?: return
+        val bindingContext = context.trace.bindingContext
+
+        if (isJsonFormatCreation(functionDescriptor)) {
+            if (isDefaultFormat(resolvedCall, bindingContext)) {
+                context.trace.report(SerializationErrors.JSON_FORMAT_REDUNDANT_DEFAULT.on(resolvedCall.call.callElement))
+            }
+            return
+        }
+
+        val receiverExpression = resolvedCall.getReceiverExpression() ?: return
+        val receiverResolvedCall = receiverExpression.getResolvedCall(bindingContext) ?: return
+        val receiverFunctionDescriptor = receiverResolvedCall.resultingDescriptor as? SimpleFunctionDescriptor ?: return
+
+        if (isJsonFormatCreation(receiverFunctionDescriptor) && !isDefaultFormat(receiverResolvedCall, bindingContext)) {
+            context.trace.report(SerializationErrors.JSON_FORMAT_REDUNDANT.on(receiverExpression.originalElement))
+        }
+    }
+
+    private fun isJsonFormatCreation(descriptor: SimpleFunctionDescriptor): Boolean {
+        return descriptor.importableFqName == jsonFqName
+    }
+
+    private fun isDefaultFormat(resolvedCall: ResolvedCall<*>, context: BindingContext): Boolean {
+        var defaultFrom = false
+        var emptyBuilder = false
+
+        resolvedCall.valueArguments.forEach { (paramDesc, arg) ->
+            when (paramDesc.name) {
+                parameterNameFrom -> defaultFrom = isDefaultFormatArgument(arg, context)
+                parameterNameBuilderAction -> emptyBuilder = isEmptyFunctionArgument(arg)
+            }
+        }
+
+        return defaultFrom && emptyBuilder
+    }
+
+    private fun isDefaultFormatArgument(arg: ResolvedValueArgument, context: BindingContext): Boolean {
+        if (arg is DefaultValueArgument) return true
+        if (arg !is ExpressionValueArgument) return false
+        val expression = arg.valueArgument?.getArgumentExpression() ?: return false
+
+        val fqName = context[BindingContext.EXPRESSION_TYPE_INFO, expression]?.type?.fqName ?: return false
+        return fqName == jsonDefaultFqName
+    }
+
+    private fun isEmptyFunctionArgument(arg: ResolvedValueArgument): Boolean {
+        if (arg !is ExpressionValueArgument) {
+            return false
+        }
+        val argumentExpression = arg.valueArgument?.getArgumentExpression() ?: return false
+
+        val blockExpression = if (argumentExpression is KtNamedFunction) {
+            // anonymous functions
+            argumentExpression.bodyBlockExpression ?: return true
+        } else {
+            // function literal
+            argumentExpression.unpackFunctionLiteral()?.bodyExpression
+        }
+
+        return blockExpression?.statements?.isEmpty() ?: false
+    }
+}

plugins/kotlin-serialization/kotlin-serialization-ide/src/org/jetbrains/kotlinx/serialization/compiler/extensions/SerializationIDEContainerContributor.kt

@@ -10,6 +10,7 @@ import org.jetbrains.kotlin.container.useInstance
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.extensions.StorageComponentContainerContributor
 import org.jetbrains.kotlin.platform.TargetPlatform
+import org.jetbrains.kotlinx.serialization.compiler.diagnostic.JsonFormatRedundantDiagnostic
 import org.jetbrains.kotlinx.serialization.compiler.diagnostic.SerializationPluginIDEDeclarationChecker
 
 class SerializationIDEContainerContributor : StorageComponentContainerContributor {
@@ -19,5 +20,6 @@ class SerializationIDEContainerContributor : StorageComponentContainerContributo
         moduleDescriptor: ModuleDescriptor
     ) {
         container.useInstance(SerializationPluginIDEDeclarationChecker())
+        container.useInstance(JsonFormatRedundantDiagnostic())
     }
-}
+}

plugins/kotlin-serialization/kotlin-serialization-ide/src/org/jetbrains/kotlinx/serialization/idea/KotlinSerializationBundle.kt

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlinx.serialization.idea
+
+import org.jetbrains.annotations.NonNls
+import org.jetbrains.annotations.PropertyKey
+import org.jetbrains.kotlin.util.AbstractKotlinBundle
+
+@NonNls
+private const val BUNDLE = "messages.KotlinSerializationBundle"
+
+object KotlinSerializationBundle : AbstractKotlinBundle(BUNDLE) {
+    @JvmStatic
+    fun message(@NonNls @PropertyKey(resourceBundle = BUNDLE) key: String, vararg params: Any): String = getMessage(key, *params)
+
+    @JvmStatic
+    fun htmlMessage(@NonNls @PropertyKey(resourceBundle = BUNDLE) key: String, vararg params: Any): String =
+        getMessage(key, *params).withHtml()
+}

plugins/kotlin-serialization/kotlin-serialization-ide/src/org/jetbrains/kotlinx/serialization/idea/quickfixes/JsonRedundantDefaultQuickFix.kt

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlinx.serialization.idea.quickfixes
+
+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.idea.quickfix.KotlinQuickFixAction
+import org.jetbrains.kotlin.idea.quickfix.KotlinSingleIntentionActionFactory
+import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlinx.serialization.compiler.diagnostic.SerializationErrors
+import org.jetbrains.kotlinx.serialization.idea.KotlinSerializationBundle
+
+internal class JsonRedundantDefaultQuickFix(expression: KtCallExpression) : KotlinQuickFixAction<KtCallExpression>(expression) {
+    override fun invoke(project: Project, editor: Editor?, file: KtFile) {
+        val element = element ?: return
+        val call = element as? KtCallExpression ?: return
+        val callee = call.calleeExpression ?: return
+        call.replace(callee)
+    }
+
+    override fun getFamilyName(): String = text
+
+    override fun getText(): String = KotlinSerializationBundle.message("replace.with.default.json.format")
+
+    object Factory : KotlinSingleIntentionActionFactory() {
+        override fun createAction(diagnostic: Diagnostic): IntentionAction? {
+            if (diagnostic.factory != SerializationErrors.JSON_FORMAT_REDUNDANT_DEFAULT) return null
+            val castedDiagnostic = SerializationErrors.JSON_FORMAT_REDUNDANT_DEFAULT.cast(diagnostic)
+
+            val element: KtCallExpression = castedDiagnostic.psiElement as? KtCallExpression ?: return null
+            return JsonRedundantDefaultQuickFix(element)
+        }
+    }
+}

plugins/kotlin-serialization/kotlin-serialization-ide/src/org/jetbrains/kotlinx/serialization/idea/quickfixes/JsonRedundantQuickFix.kt

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlinx.serialization.idea.quickfixes
+
+import com.intellij.codeInsight.intention.IntentionAction
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.editor.ScrollType
+import com.intellij.openapi.project.Project
+import com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.diagnostics.Diagnostic
+import org.jetbrains.kotlin.idea.KotlinBundle
+import org.jetbrains.kotlin.idea.quickfix.KotlinQuickFixAction
+import org.jetbrains.kotlin.idea.quickfix.KotlinSingleIntentionActionFactory
+import org.jetbrains.kotlin.idea.refactoring.chooseContainerElementIfNecessary
+import org.jetbrains.kotlin.idea.refactoring.getExtractionContainers
+import org.jetbrains.kotlin.idea.refactoring.introduce.extractionEngine.*
+import org.jetbrains.kotlin.idea.refactoring.introduce.introduceProperty.KotlinIntroducePropertyHandler
+import org.jetbrains.kotlin.idea.refactoring.introduce.showErrorHintByKey
+import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.psi.psiUtil.getOutermostParentContainedIn
+import org.jetbrains.kotlinx.serialization.compiler.diagnostic.SerializationErrors
+import org.jetbrains.kotlinx.serialization.idea.KotlinSerializationBundle
+
+internal class JsonRedundantQuickFix(expression: KtCallExpression) : KotlinQuickFixAction<KtCallExpression>(expression) {
+    override fun invoke(project: Project, editor: Editor?, file: KtFile) {
+        editor ?: return
+        val element = element ?: return
+
+        selectContainer(element, project, editor) {
+            editor.scrollingModel.scrollToCaret(ScrollType.MAKE_VISIBLE)
+
+            val outermostParent = element.getOutermostParentContainedIn(it)
+            if (outermostParent == null) {
+                showErrorHintByKey(project, editor, "cannot.refactor.no.container", text)
+                return@selectContainer
+            }
+            KotlinIntroducePropertyHandler().doInvoke(project, editor, file, listOf(element), outermostParent)
+        }
+    }
+
+    override fun getFamilyName(): String = text
+
+    override fun getText(): String = KotlinSerializationBundle.message("extract.json.to.property")
+
+    object Factory : KotlinSingleIntentionActionFactory() {
+        override fun createAction(diagnostic: Diagnostic): IntentionAction? {
+            if (diagnostic.factory != SerializationErrors.JSON_FORMAT_REDUNDANT) return null
+            val castedDiagnostic = SerializationErrors.JSON_FORMAT_REDUNDANT.cast(diagnostic)
+
+            val element: KtCallExpression = castedDiagnostic.psiElement as? KtCallExpression ?: return null
+            return JsonRedundantQuickFix(element)
+        }
+    }
+
+    private fun selectContainer(element: PsiElement, project: Project, editor: Editor, onSelect: (PsiElement) -> Unit) {
+        val parent = element.parent ?: throw AssertionError("Should have at least one parent")
+
+        val containers = parent.getExtractionContainers(strict = true, includeAll = true)
+            .filter { it is KtClassBody || (it is KtFile && !it.isScript()) }
+
+        if (containers.isEmpty()) {
+            showErrorHintByKey(project, editor, "cannot.refactor.no.container", text)
+            return
+        }
+
+        chooseContainerElementIfNecessary(
+            containers,
+            editor,
+            KotlinBundle.message("title.select.target.code.block"),
+            true,
+            { it },
+            { onSelect(it) }
+        )
+    }
+
+}

plugins/kotlin-serialization/kotlin-serialization-ide/src/org/jetbrains/kotlinx/serialization/idea/quickfixes/SerializationQuickFixContributor.kt

@@ -12,5 +12,7 @@ import org.jetbrains.kotlinx.serialization.compiler.diagnostic.SerializationErro
 class SerializationQuickFixContributor : QuickFixContributor {
     override fun registerQuickFixes(quickFixes: QuickFixes) {
         quickFixes.register(SerializationErrors.INCORRECT_TRANSIENT, AddKotlinxSerializationTransientImportQuickFix.Factory)
+        quickFixes.register(SerializationErrors.JSON_FORMAT_REDUNDANT_DEFAULT, JsonRedundantDefaultQuickFix.Factory)
+        quickFixes.register(SerializationErrors.JSON_FORMAT_REDUNDANT, JsonRedundantQuickFix.Factory)
     }
-}
+}

plugins/kotlin-serialization/kotlin-serialization-ide/test/org/jetbrains/kotlinx/serialization/idea/AbstractSerializationPluginIdeDiagnosticTest.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlinx.serialization.idea
+
+import org.jetbrains.kotlin.ObsoleteTestInfrastructure
+import org.jetbrains.kotlin.checkers.AbstractDiagnosticsTest
+import org.jetbrains.kotlin.cli.jvm.compiler.KotlinCoreEnvironment
+import org.jetbrains.kotlin.cli.jvm.config.JvmClasspathRoot
+import org.jetbrains.kotlin.extensions.StorageComponentContainerContributor
+import org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationIDEContainerContributor
+
+@OptIn(ObsoleteTestInfrastructure::class)
+abstract class AbstractSerializationPluginIdeDiagnosticTest : AbstractDiagnosticsTest() {
+    private val coreLibraryPath = getSerializationCoreLibraryJar()!!
+    private val jsonLibraryPath = getSerializationJsonLibraryJar()!!
+
+    override fun setupEnvironment(environment: KotlinCoreEnvironment) {
+        if (!StorageComponentContainerContributor.getInstances(project).any { it is SerializationIDEContainerContributor }) {
+            StorageComponentContainerContributor.registerExtension(project, SerializationIDEContainerContributor())
+        }
+        environment.updateClasspath(listOf(JvmClasspathRoot(coreLibraryPath), JvmClasspathRoot(jsonLibraryPath)))
+    }
+}

plugins/kotlin-serialization/kotlin-serialization-ide/test/org/jetbrains/kotlinx/serialization/idea/AbstractSerializationQuickFixTest.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlinx.serialization.idea
+
+import org.jetbrains.kotlin.idea.quickfix.AbstractQuickFixTest
+import org.jetbrains.kotlin.idea.test.ConfigLibraryUtil
+
+abstract class AbstractSerializationQuickFixTest : AbstractQuickFixTest() {
+    override fun setUp() {
+        super.setUp()
+        val coreJar = getSerializationCoreLibraryJar()!!
+        val jsonJar = getSerializationJsonLibraryJar()!!
+        ConfigLibraryUtil.addLibrary(module, "Serialization core", coreJar.parentFile.absolutePath, arrayOf(coreJar.name))
+        ConfigLibraryUtil.addLibrary(module, "Serialization JSON", jsonJar.parentFile.absolutePath, arrayOf(jsonJar.name))
+    }
+
+    override fun tearDown() {
+        ConfigLibraryUtil.removeLibrary(module, "Serialization JSON")
+        ConfigLibraryUtil.removeLibrary(module, "Serialization core")
+
+        super.tearDown()
+    }
+}

plugins/kotlin-serialization/kotlin-serialization-ide/test/org/jetbrains/kotlinx/serialization/idea/RuntimeSearch.kt

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlinx.serialization.idea
+
+import junit.framework.TestCase
+import org.jetbrains.kotlin.utils.PathUtil
+import org.jetbrains.kotlinx.serialization.compiler.diagnostic.VersionReader
+import org.junit.Test
+import java.io.File
+import kotlin.test.assertTrue
+
+class RuntimeLibraryInClasspathTest {
+    private val runtimeLibraryPath = getSerializationCoreLibraryJar()
+
+    @Test
+    fun testRuntimeLibraryExists() {
+        TestCase.assertNotNull(
+            "kotlinx-serialization runtime library is not found. Make sure it is present in test classpath",
+            runtimeLibraryPath
+        )
+    }
+
+    @Test
+    fun testRuntimeHasSufficientVersion() {
+        val version = VersionReader.getVersionsFromManifest(runtimeLibraryPath!!)
+        assertTrue(version.currentCompilerMatchRequired(), "Runtime version too high")
+        assertTrue(version.implementationVersionMatchSupported(), "Runtime version too low")
+    }
+}
+
+internal fun getSerializationCoreLibraryJar(): File? = try {
+    PathUtil.getResourcePathForClass(Class.forName("kotlinx.serialization.KSerializer"))
+} catch (e: ClassNotFoundException) {
+    null
+}
+
+internal fun getSerializationJsonLibraryJar(): File? = try {
+    PathUtil.getResourcePathForClass(Class.forName("kotlinx.serialization.json.Json"))
+} catch (e: ClassNotFoundException) {
+    null
+}

plugins/kotlin-serialization/kotlin-serialization-ide/test/org/jetbrains/kotlinx/serialization/idea/SerializationPluginIdeDiagnosticTestGenerated.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlinx.serialization.idea;
+
+import com.intellij.testFramework.TestDataPath;
+import org.jetbrains.kotlin.test.JUnit3RunnerWithInners;
+import org.jetbrains.kotlin.test.KotlinTestUtils;
+import org.jetbrains.kotlin.test.util.KtTestUtil;
+import org.jetbrains.kotlin.test.TestMetadata;
+import org.junit.runner.RunWith;
+
+import java.io.File;
+import java.util.regex.Pattern;
+
+/** This class is generated by {@link org.jetbrains.kotlin.generators.tests.TestsPackage}. DO NOT MODIFY MANUALLY */
+@SuppressWarnings("all")
+@TestMetadata("plugins/kotlin-serialization/kotlin-serialization-ide/testData/diagnostics")
+@TestDataPath("$PROJECT_ROOT")
+@RunWith(JUnit3RunnerWithInners.class)
+public class SerializationPluginIdeDiagnosticTestGenerated extends AbstractSerializationPluginIdeDiagnosticTest {
+    private void runTest(String testDataFilePath) throws Exception {
+        KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
+    }
+
+    public void testAllFilesPresentInDiagnostics() throws Exception {
+        KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("plugins/kotlin-serialization/kotlin-serialization-ide/testData/diagnostics"), Pattern.compile("^(.+)\\.kt$"), null, true);
+    }
+
+    @TestMetadata("JsonRedundantFormat.kt")
+    public void testJsonRedundantFormat() throws Exception {
+        runTest("plugins/kotlin-serialization/kotlin-serialization-ide/testData/diagnostics/JsonRedundantFormat.kt");
+    }
+}

plugins/kotlin-serialization/kotlin-serialization-ide/test/org/jetbrains/kotlinx/serialization/idea/SerializationQuickFixTestGenerated.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlinx.serialization.idea;
+
+import com.intellij.testFramework.TestDataPath;
+import org.jetbrains.kotlin.test.JUnit3RunnerWithInners;
+import org.jetbrains.kotlin.test.KotlinTestUtils;
+import org.jetbrains.kotlin.test.util.KtTestUtil;
+import org.jetbrains.kotlin.test.TestMetadata;
+import org.junit.runner.RunWith;
+
+import java.io.File;
+import java.util.regex.Pattern;
+
+/** This class is generated by {@link org.jetbrains.kotlin.generators.tests.TestsPackage}. DO NOT MODIFY MANUALLY */
+@SuppressWarnings("all")
+@TestMetadata("plugins/kotlin-serialization/kotlin-serialization-ide/testData/quickfix")
+@TestDataPath("$PROJECT_ROOT")
+@RunWith(JUnit3RunnerWithInners.class)
+public class SerializationQuickFixTestGenerated extends AbstractSerializationQuickFixTest {
+    private void runTest(String testDataFilePath) throws Exception {
+        KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
+    }
+
+    public void testAllFilesPresentInQuickfix() throws Exception {
+        KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("plugins/kotlin-serialization/kotlin-serialization-ide/testData/quickfix"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), null, true);
+    }
+
+    @TestMetadata("DefaultFormat.kt")
+    public void testDefaultFormat() throws Exception {
+        runTest("plugins/kotlin-serialization/kotlin-serialization-ide/testData/quickfix/DefaultFormat.kt");
+    }
+
+    @TestMetadata("DefaultFormatWithAlias.kt")
+    public void testDefaultFormatWithAlias() throws Exception {
+        runTest("plugins/kotlin-serialization/kotlin-serialization-ide/testData/quickfix/DefaultFormatWithAlias.kt");
+    }
+}

plugins/kotlin-serialization/kotlin-serialization-ide/testData/diagnostics/JsonRedundantFormat.kt

@@ -0,0 +1,82 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER,-UNUSED_VARIABLE
+// SKIP_TXT
+
+// FILE: test.kt
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+
+object Instance
+
+val defaultWarn = <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json {}<!>
+val receiverWarn = <!JSON_FORMAT_REDUNDANT!>Json {encodeDefaults = true}<!>.encodeToString(Instance)
+val noWarnFormat = Json {encodeDefaults = true}
+val receiverNoWarn = noWarnFormat.encodeToString(Instance)
+val defaultNoWarn = Json.encodeToString(Instance)
+
+class SomeContainerClass {
+    val memberDefaultWarn = <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json {}<!>
+    val memberReceiverWarn = <!JSON_FORMAT_REDUNDANT!>Json {encodeDefaults = true}<!>.encodeToString(Instance)
+    val memberNoWarnFormat = Json {encodeDefaults = true}
+    val memberReceiverNoWarn = noWarnFormat.encodeToString(Instance)
+    val memberDefaultNoWarn = Json.encodeToString(Instance)
+
+    fun testDefaultWarnings() {
+        <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json {}<!>
+        <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json() {}<!>
+        <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json {}<!>.encodeToString(Any())
+        <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json {}<!>.encodeToString(Instance)
+        <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json { /*some comment*/ }<!>.encodeToString(Instance)
+        val localDefaultFormat = <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json {}<!>
+        <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json(Json.Default) {}<!>
+        <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json(Json) {}<!>
+        <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json(Json.Default, {})<!>
+        <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json(builderAction = {})<!>
+        <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json(builderAction = fun JsonBuilder.() {})<!>
+        <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json(builderAction = fun JsonBuilder.() = Unit)<!>
+
+        "{}".let {
+            <!JSON_FORMAT_REDUNDANT_DEFAULT!>Json {}<!>.decodeFromString<Any>(it)
+        }
+    }
+
+    fun testReceiverWarnings() {
+        <!JSON_FORMAT_REDUNDANT!>Json {encodeDefaults = true}<!>.encodeToString(Instance)
+        val encoded = <!JSON_FORMAT_REDUNDANT!>Json {encodeDefaults = true}<!>.encodeToString(Instance)
+        <!JSON_FORMAT_REDUNDANT!>Json {encodeDefaults = true}<!>.decodeFromString<Any>("{}")
+        <!JSON_FORMAT_REDUNDANT!>Json {encodeDefaults = true}<!>.hashCode()
+        <!JSON_FORMAT_REDUNDANT!>Json {encodeDefaults = true}<!>.toString()
+
+        <!JSON_FORMAT_REDUNDANT!>Json(noWarnFormat) {encodeDefaults = true}<!>.encodeToString(Instance)
+        <!JSON_FORMAT_REDUNDANT!>Json(builderAction = {encodeDefaults = true})<!>.encodeToString(Instance)
+        <!JSON_FORMAT_REDUNDANT!>Json(noWarnFormat, {encodeDefaults = true})<!>.encodeToString(Instance)
+        <!JSON_FORMAT_REDUNDANT!>Json(builderAction = fun JsonBuilder.() {encodeDefaults = true})<!>.encodeToString(Instance)
+
+        "{}".let {
+            <!JSON_FORMAT_REDUNDANT!>Json {encodeDefaults = true}<!>.decodeFromString<Any>(it)
+        }
+    }
+
+    fun testReceiverNoWarnings() {
+        val localFormat = Json {encodeDefaults = true}
+        localFormat.encodeToString(Instance)
+        localFormat.decodeFromString<Any>("{}")
+        localFormat.hashCode()
+        localFormat.toString()
+    }
+
+    fun testDefaultNoWarnings() {
+        val localDefault = Json
+        Json.encodeToString(Instance)
+        Json.decodeFromString<Any>("{}")
+        Json.hashCode()
+        Json.toString()
+        Json(builderAction = this::builder)
+        Json(Json.Default, this::builder)
+    }
+
+    private fun builder(builder: JsonBuilder) {
+        //now its empty builder
+    }
+}
+
+

plugins/kotlin-serialization/kotlin-serialization-ide/testData/quickfix/DefaultFormat.kt

@@ -0,0 +1,7 @@
+// "Replace with default Json format instance" "true"
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+
+fun foo() {
+    <caret>Json {}.encodeToString(Any())
+}

plugins/kotlin-serialization/kotlin-serialization-ide/testData/quickfix/DefaultFormat.kt.after

@@ -0,0 +1,7 @@
+// "Replace with default Json format instance" "true"
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+
+fun foo() {
+    Json.encodeToString(Any())
+}

plugins/kotlin-serialization/kotlin-serialization-ide/testData/quickfix/DefaultFormatWithAlias.kt

@@ -0,0 +1,8 @@
+// "Replace with default Json format instance" "true"
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+import kotlinx.serialization.json.Json as Alias
+
+fun foo() {
+    <caret>Alias {}
+}

plugins/kotlin-serialization/kotlin-serialization-ide/testData/quickfix/DefaultFormatWithAlias.kt.after

@@ -0,0 +1,8 @@
+// "Replace with default Json format instance" "true"
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+import kotlinx.serialization.json.Json as Alias
+
+fun foo() {
+    Alias
+}