drewhamilton · Sep 16, 2026 · Sep 9, 2026 · Sep 16, 2026
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -77,7 +77,7 @@ jobs:
         # Keep past dev versions too; try to target active versions of IntelliJ based on tags in
         # https://github.com/JetBrains/kotlin. Can also use
         # https://github.com/ZacSweers/metro/blob/main/docs/compatibility.md as a reference.
-        poko_sample_kotlin_version: [ 2.4.0-dev-2124, 2.4.0, ~, 2.4.20-dev-4664, 2.4.20 ]
+        poko_sample_kotlin_version: [ 2.4.0-dev-2124, 2.4.0, 2.4.10, 2.4.20-dev-4664, ~ ]
     env:
       poko_sample_kotlin_version: ${{ matrix.poko_sample_kotlin_version }}
     steps:

diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
@@ -2,7 +2,7 @@
 
 androidx-compose-runtime = "1.12.1"
 
-kotlin = "2.4.10"
+kotlin = "2.4.20"
 kotlinCompileTesting = "1.6.0"
 # https://central.sonatype.com/artifact/dev.zacsweers.kctfork/core/versions:
 kotlinCompileTestingFork = "0.13.0"

diff --git a/kotlin-js-store/yarn.lock b/kotlin-js-store/yarn.lock
@@ -254,10 +254,10 @@ js-yaml@^4.1.0:
   dependencies:
     argparse "^2.0.1"
 
-kotlin-web-helpers@3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/kotlin-web-helpers/-/kotlin-web-helpers-3.0.0.tgz#3ed6b48f694f74bb60a737a9d7e2c0e3b29abdb9"
-  integrity sha512-kdQO4AJQkUPvpLh9aglkXDRyN+CfXO7pKq+GESEnxooBFkQpytLrqZis3ABvmFN1cGw/ZQ/K38u5sRGW+NfBnw==
+kotlin-web-helpers@3.3.0:
+  version "3.3.0"
+  resolved "https://registry.yarnpkg.com/kotlin-web-helpers/-/kotlin-web-helpers-3.3.0.tgz#4c0bf6bcfa64752f6f1531e4c84583943bc7e9d6"
+  integrity sha512-sXnwHZ2YGMtIia+NQlf/c0UDtwVNHhXsIH+uHkTv87AvvZQJjJ+XbdkvUUuomPWgBC5TgcQLDEGLcjL48QkFkQ==
   dependencies:
     format-util "^1.0.5"
 
@@ -293,10 +293,10 @@ minimatch@^9.0.4, minimatch@^9.0.5:
   resolved "https://registry.yarnpkg.com/minipass/-/minipass-7.1.3.tgz#79389b4eb1bb2d003a9bba87d492f2bd37bdc65b"
   integrity sha512-tEBHqDnIoM/1rXME1zgka9g6Q2lcoCkxHLuc7ODJ5BxbP5d4c2Z5cGgtXAku59200Cx7diuHTOYfSBD8n6mm8A==
 
-mocha@11.7.5:
-  version "11.7.5"
-  resolved "https://registry.yarnpkg.com/mocha/-/mocha-11.7.5.tgz#58f5bbfa5e0211ce7e5ee6128107cefc2515a627"
-  integrity sha512-mTT6RgopEYABzXWFx+GcJ+ZQ32kp4fMf0xvpZIIfSq9Z8lC/++MtcCnQ9t5FP2veYEP95FIYSvW+U9fV4xrlig==
+mocha@11.7.6:
+  version "11.7.6"
+  resolved "https://registry.yarnpkg.com/mocha/-/mocha-11.7.6.tgz#ebbe22989d04cbb9424a36307320476624c41a33"
+  integrity sha512-nS9xOGbw2I3cjCpxwZAEJ9xK9lmJ08vEkQvLtz4du9ZrF9UrjRpeJGiIgl2Z+Qs++pmB4ecDe48Fwsh+j+j7xA==
   dependencies:
     browser-stdout "^1.3.1"
     chokidar "^4.0.1"

diff --git a/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/PokoCompilerPluginRegistrar.kt b/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/PokoCompilerPluginRegistrar.kt
@@ -1,16 +1,14 @@
 package dev.drewhamilton.poko
 
 import com.google.auto.service.AutoService
-import dev.drewhamilton.poko.BuildConfig.DEFAULT_POKO_FIR_IDE_MODE
 import dev.drewhamilton.poko.BuildConfig.DEFAULT_POKO_ANNOTATION
 import dev.drewhamilton.poko.BuildConfig.DEFAULT_POKO_ENABLED
+import dev.drewhamilton.poko.BuildConfig.DEFAULT_POKO_FIR_IDE_MODE
 import dev.drewhamilton.poko.fir.PokoFirExtensionRegistrar
 import dev.drewhamilton.poko.ir.PokoIrGenerationExtension
 import org.jetbrains.kotlin.backend.common.extensions.IrGenerationExtension
-import org.jetbrains.kotlin.cli.common.messages.MessageCollector
 import org.jetbrains.kotlin.compiler.plugin.CompilerPluginRegistrar
 import org.jetbrains.kotlin.compiler.plugin.ExperimentalCompilerApi
-import org.jetbrains.kotlin.config.CommonConfigurationKeys
 import org.jetbrains.kotlin.config.CompilerConfiguration
 import org.jetbrains.kotlin.fir.extensions.FirExtensionRegistrarAdapter
 import org.jetbrains.kotlin.name.ClassId
@@ -34,15 +32,9 @@ public class PokoCompilerPluginRegistrar : CompilerPluginRegistrar() {
             FirIdeMode.valueOf(DEFAULT_POKO_FIR_IDE_MODE),
         )
 
-        val messageCollector = configuration.get(
-            CommonConfigurationKeys.MESSAGE_COLLECTOR_KEY,
-            MessageCollector.NONE,
-        )
-
         IrGenerationExtension.registerExtension(
             PokoIrGenerationExtension(
                 pokoAnnotationName = pokoAnnotationClassId,
-                messageCollector = messageCollector,
             )
         )
 

diff --git a/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/PokoFunctionBodyFiller.kt b/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/PokoFunctionBodyFiller.kt
@@ -5,7 +5,6 @@ import dev.drewhamilton.poko.fir.PokoKey
 import org.jetbrains.kotlin.GeneratedDeclarationKey
 import org.jetbrains.kotlin.backend.common.extensions.IrPluginContext
 import org.jetbrains.kotlin.backend.common.lower.DeclarationIrBuilder
-import org.jetbrains.kotlin.cli.common.messages.MessageCollector
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.builders.irBlockBody
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
@@ -26,7 +25,6 @@ import org.jetbrains.kotlin.name.ClassId
 internal class PokoFunctionBodyFiller(
     private val pokoAnnotation: ClassId,
     private val context: IrPluginContext,
-    private val messageCollector: MessageCollector,
 ) : IrVisitorVoid() {
 
     override fun visitSimpleFunction(declaration: IrSimpleFunction) {
@@ -47,8 +45,7 @@ internal class PokoFunctionBodyFiller(
         val pokoClass = declaration.parentAsClass
         val pokoProperties = pokoClass.pokoProperties(pokoAnnotation).also {
             if (it.isEmpty()) {
-                messageCollector.log("No primary constructor properties")
-                messageCollector.reportErrorOnClass(
+                context.diagnosticReporter.reportErrorOnClass(
                     irClass = pokoClass,
                     message = "Poko class primary constructor must have at least one not-skipped property",
                 )
@@ -66,15 +63,13 @@ internal class PokoFunctionBodyFiller(
                     irClass = pokoClass,
                     functionDeclaration = declaration,
                     classProperties = pokoProperties,
-                    messageCollector = messageCollector,
                 )
 
                 PokoFunction.HashCode -> generateHashCodeMethodBody(
                     pokoAnnotation = pokoAnnotation,
                     context = this@PokoFunctionBodyFiller.context,
                     functionDeclaration = declaration,
                     classProperties = pokoProperties,
-                    messageCollector = messageCollector,
                 )
 
                 PokoFunction.ToString -> generateToStringMethodBody(
@@ -83,7 +78,6 @@ internal class PokoFunctionBodyFiller(
                     irClass = pokoClass,
                     functionDeclaration = declaration,
                     classProperties = pokoProperties,
-                    messageCollector = messageCollector,
                 )
             }
         }

diff --git a/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/PokoIrGenerationExtension.kt b/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/PokoIrGenerationExtension.kt
@@ -2,36 +2,28 @@ package dev.drewhamilton.poko.ir
 
 import org.jetbrains.kotlin.backend.common.extensions.IrGenerationExtension
 import org.jetbrains.kotlin.backend.common.extensions.IrPluginContext
-import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity
-import org.jetbrains.kotlin.cli.common.messages.MessageCollector
-import org.jetbrains.kotlin.cli.common.messages.MessageUtil
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment
+import org.jetbrains.kotlin.ir.validation.IrValidationSeverity
 import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
-import org.jetbrains.kotlin.js.resolve.diagnostics.findPsi
 import org.jetbrains.kotlin.name.ClassId
 
 internal class PokoIrGenerationExtension(
     private val pokoAnnotationName: ClassId,
-    private val messageCollector: MessageCollector
 ) : IrGenerationExtension {
 
     override fun generate(moduleFragment: IrModuleFragment, pluginContext: IrPluginContext) {
         if (pluginContext.referenceClass(pokoAnnotationName) == null) {
-            moduleFragment.reportError("Could not find class <$pokoAnnotationName>")
+            pluginContext.diagnosticReporter.report(
+                factory = IrValidationSeverity.ERROR.factory,
+                message = "Could not find class <$pokoAnnotationName>",
+            )
             return
         }
 
         val bodyFiller = PokoFunctionBodyFiller(
             pokoAnnotation = pokoAnnotationName,
             context = pluginContext,
-            messageCollector = messageCollector,
         )
         moduleFragment.acceptChildrenVoid(bodyFiller)
     }
-
-    private fun IrModuleFragment.reportError(message: String) {
-        val psi = descriptor.findPsi()
-        val location = MessageUtil.psiElementToMessageLocation(psi)
-        messageCollector.report(CompilerMessageSeverity.ERROR, message, location)
-    }
 }
diff --git a/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/equalsGeneration.kt b/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/equalsGeneration.kt
@@ -3,7 +3,6 @@ package dev.drewhamilton.poko.ir
 import org.jetbrains.kotlin.backend.common.extensions.IrPluginContext
 import org.jetbrains.kotlin.backend.common.lower.irNot
 import org.jetbrains.kotlin.builtins.PrimitiveType
-import org.jetbrains.kotlin.cli.common.messages.MessageCollector
 import org.jetbrains.kotlin.ir.builders.IrBlockBodyBuilder
 import org.jetbrains.kotlin.ir.builders.IrBuilderWithScope
 import org.jetbrains.kotlin.ir.builders.irBranch
@@ -55,7 +54,6 @@ internal fun IrBlockBodyBuilder.generateEqualsMethodBody(
     irClass: IrClass,
     functionDeclaration: IrFunction,
     classProperties: List<IrProperty>,
-    messageCollector: MessageCollector,
 ) {
     val irType = irClass.defaultType
     fun irOther(): IrExpression = IrGetValueImpl(
@@ -78,7 +76,6 @@ internal fun IrBlockBodyBuilder.generateEqualsMethodBody(
                         receiver = arg1,
                         argument = arg2,
                         property = property,
-                        messageCollector = messageCollector,
                     ),
                 )
             }
@@ -102,7 +99,6 @@ private fun IrBuilderWithScope.irArrayContentDeepEquals(
     receiver: IrExpression,
     argument: IrExpression,
     property: IrProperty,
-    messageCollector: MessageCollector,
 ): IrExpression {
     val propertyType = property.type
     val propertyClassifier = propertyType.classifierOrFail
@@ -113,7 +109,7 @@ private fun IrBuilderWithScope.irArrayContentDeepEquals(
         return if (mayBeRuntimeArray) {
             irRuntimeArrayContentDeepEquals(context, receiver, argument)
         } else {
-            messageCollector.reportErrorOnProperty(
+            context.diagnosticReporter.reportErrorOnProperty(
                 property = property,
                 message = "@ReadArrayContent is only supported on properties with array type or `Any` type",
             )

diff --git a/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/hashCodeGeneration.kt b/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/hashCodeGeneration.kt
@@ -3,7 +3,6 @@ package dev.drewhamilton.poko.ir
 import org.jetbrains.kotlin.backend.common.extensions.IrPluginContext
 import org.jetbrains.kotlin.builtins.PrimitiveType
 import org.jetbrains.kotlin.builtins.StandardNames
-import org.jetbrains.kotlin.cli.common.messages.MessageCollector
 import org.jetbrains.kotlin.ir.builders.IrBlockBodyBuilder
 import org.jetbrains.kotlin.ir.builders.irBranch
 import org.jetbrains.kotlin.ir.builders.irCall
@@ -54,7 +53,6 @@ internal fun IrBlockBodyBuilder.generateHashCodeMethodBody(
     context: IrPluginContext,
     functionDeclaration: IrFunction,
     classProperties: List<IrProperty>,
-    messageCollector: MessageCollector,
 ) {
     if (classProperties.isEmpty()) {
         +irReturn(irInt(0))
@@ -66,7 +64,6 @@ internal fun IrBlockBodyBuilder.generateHashCodeMethodBody(
                 context = context,
                 function = functionDeclaration,
                 property = classProperties[0],
-                messageCollector = messageCollector,
             ),
         )
         return
@@ -91,7 +88,6 @@ internal fun IrBlockBodyBuilder.generateHashCodeMethodBody(
             context = context,
             function = functionDeclaration,
             property = classProperties[0],
-            messageCollector = messageCollector,
         )
     }
     +irResultVar
@@ -112,7 +108,6 @@ internal fun IrBlockBodyBuilder.generateHashCodeMethodBody(
                 context = context,
                 function = functionDeclaration,
                 property = property,
-                messageCollector = messageCollector,
             ),
         )
         +irSet(irResultVar.symbol, rhs)
@@ -130,7 +125,6 @@ private fun IrBlockBodyBuilder.getHashCodeOfProperty(
     context: IrPluginContext,
     function: IrFunction,
     property: IrProperty,
-    messageCollector: MessageCollector,
 ): IrExpression {
     val field = property.backingField!!
     val irGetField = { irGetField(receiver(function), field) }
@@ -139,9 +133,9 @@ private fun IrBlockBodyBuilder.getHashCodeOfProperty(
             type = context.irBuiltIns.intType,
             subject = irGetField(),
             thenPart = irInt(0),
-            elsePart = getHashCodeOf(pokoAnnotation, context, property, irGetField(), messageCollector)
+            elsePart = getHashCodeOf(pokoAnnotation, context, property, irGetField())
         )
-        else -> getHashCodeOf(pokoAnnotation, context, property, irGetField(), messageCollector)
+        else -> getHashCodeOf(pokoAnnotation, context, property, irGetField())
     }
 }
 
@@ -155,7 +149,6 @@ private fun IrBlockBodyBuilder.getHashCodeOf(
     context: IrPluginContext,
     property: IrProperty,
     value: IrExpression,
-    messageCollector: MessageCollector,
 ): IrExpression {
     // Fast path for integers which are already their own hashCode value.
     if (property.type.isInt()) {
@@ -179,7 +172,7 @@ private fun IrBlockBodyBuilder.getHashCodeOf(
 
     // Non-null if content-based hashCode will be used, else null:
     val contentHashCodeFunctionSymbol = if (hasReadArrayContentAnnotation) {
-        maybeFindArrayContentHashCodeFunction(context, property, messageCollector)
+        maybeFindArrayContentHashCodeFunction(context, property)
     } else {
         null
     }
@@ -273,13 +266,12 @@ private fun IrBlockBodyBuilder.irArrayTypeCheckAndContentDeepHashCodeBranch(
 private fun maybeFindArrayContentHashCodeFunction(
     context: IrPluginContext,
     property: IrProperty,
-    messageCollector: MessageCollector,
 ): IrSimpleFunctionSymbol? {
     val propertyClassifier = property.type.classifierOrFail
 
     val isArray = propertyClassifier.isArrayOrPrimitiveArray(context.irBuiltIns)
     if (!isArray) {
-        messageCollector.reportErrorOnProperty(
+        context.diagnosticReporter.reportErrorOnProperty(
             property = property,
             message = "@ReadArrayContent is only supported on properties with array type or `Any` type",
         )

diff --git a/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/logging.kt b/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/logging.kt
@@ -1,26 +1,22 @@
 package dev.drewhamilton.poko.ir
 
-import org.jetbrains.kotlin.cli.common.messages.CompilerMessageSeverity
-import org.jetbrains.kotlin.cli.common.messages.MessageCollector
 import org.jetbrains.kotlin.cli.common.messages.MessageUtil
+import org.jetbrains.kotlin.ir.IrDiagnosticReporter
 import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrProperty
+import org.jetbrains.kotlin.ir.validation.IrValidationSeverity
 import org.jetbrains.kotlin.resolve.source.getPsi
 
-internal fun MessageCollector.log(message: String) {
-    report(CompilerMessageSeverity.LOGGING, "POKO COMPILER PLUGIN (IR): $message")
-}
-
-internal fun MessageCollector.reportErrorOnClass(irClass: IrClass, message: String) {
+internal fun IrDiagnosticReporter.reportErrorOnClass(irClass: IrClass, message: String) {
     val psi = irClass.source.getPsi()
     val location = MessageUtil.psiElementToMessageLocation(psi)
-    report(CompilerMessageSeverity.ERROR, message, location)
+    report(IrValidationSeverity.ERROR.factory, message, location)
 }
 
-@OptIn(ObsoleteDescriptorBasedAPI::class) // Only needed for non-K2 compilation
-internal fun MessageCollector.reportErrorOnProperty(property: IrProperty, message: String) {
+@OptIn(ObsoleteDescriptorBasedAPI::class) // TODO: Try to do this without the descriptor
+internal fun IrDiagnosticReporter.reportErrorOnProperty(property: IrProperty, message: String) {
     val psi = property.descriptor.source.getPsi()
     val location = MessageUtil.psiElementToMessageLocation(psi)
-    report(CompilerMessageSeverity.ERROR, message, location)
+    report(IrValidationSeverity.ERROR.factory, message, location)
 }
diff --git a/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/toStringGeneration.kt b/poko-compiler-plugin/src/main/kotlin/dev/drewhamilton/poko/ir/toStringGeneration.kt
@@ -2,7 +2,6 @@ package dev.drewhamilton.poko.ir
 
 import org.jetbrains.kotlin.backend.common.extensions.IrPluginContext
 import org.jetbrains.kotlin.builtins.PrimitiveType
-import org.jetbrains.kotlin.cli.common.messages.MessageCollector
 import org.jetbrains.kotlin.ir.builders.IrBlockBodyBuilder
 import org.jetbrains.kotlin.ir.builders.irBranch
 import org.jetbrains.kotlin.ir.builders.irCall
@@ -48,7 +47,6 @@ internal fun IrBlockBodyBuilder.generateToStringMethodBody(
     irClass: IrClass,
     functionDeclaration: IrFunction,
     classProperties: List<IrProperty>,
-    messageCollector: MessageCollector,
 ) {
     val irConcat = irConcat()
     irConcat.addArgument(irString(irClass.name.asString() + "("))
@@ -74,7 +72,6 @@ internal fun IrBlockBodyBuilder.generateToStringMethodBody(
                 val toStringFunctionSymbol = maybeFindArrayDeepToStringFunction(
                     context = context,
                     property = property,
-                    messageCollector = messageCollector
                 ) ?: context.irBuiltIns.dataClassArrayMemberToStringSymbol
                 irCallToStringFunction(
                     toStringFunctionSymbol = toStringFunctionSymbol,
@@ -107,13 +104,12 @@ internal fun IrBlockBodyBuilder.generateToStringMethodBody(
 private fun maybeFindArrayDeepToStringFunction(
     context: IrPluginContext,
     property: IrProperty,
-    messageCollector: MessageCollector,
 ): IrSimpleFunctionSymbol? {
     val propertyClassifier = property.type.classifierOrFail
 
     val isArray = propertyClassifier.isArrayOrPrimitiveArray(context.irBuiltIns)
     if (!isArray) {
-        messageCollector.reportErrorOnProperty(
+        context.diagnosticReporter.reportErrorOnProperty(
             property = property,
             message = "@ReadArrayContent is only supported on properties with array type or `Any` type",
         )