[K/JS] Introduce a checker for @JsExport.Default usage in a single file

JSMonk · Space Team · commit 1480fb431956 · 2025-10-08T20:39:20.000Z
^KT-80401
diff --git a/analysis/analysis-api-fir/gen/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KaFirDataClassConverters.kt b/analysis/analysis-api-fir/gen/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KaFirDataClassConverters.kt
@@ -7211,6 +7211,12 @@ internal val KT_DIAGNOSTIC_CONVERTER = KaDiagnosticConverterBuilder.buildConvert
             token,
         )
     }
+    add(FirWebCommonErrors.MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE) { firDiagnostic ->
+        MultipleJsExportDefaultInOneFileImpl(
+            firDiagnostic as KtPsiDiagnostic,
+            token,
+        )
+    }
     add(FirJsErrors.DELEGATION_BY_DYNAMIC) { firDiagnostic ->
         DelegationByDynamicImpl(
             firDiagnostic as KtPsiDiagnostic,
diff --git a/analysis/analysis-api-fir/gen/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KaFirDiagnostics.kt b/analysis/analysis-api-fir/gen/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KaFirDiagnostics.kt
@@ -5045,6 +5045,10 @@ sealed interface KaFirDiagnostic<PSI : PsiElement> : KaDiagnosticWithPsi<PSI> {
         override val diagnosticClass get() = NestedJsExport::class
     }
 
+    interface MultipleJsExportDefaultInOneFile : KaFirDiagnostic<KtElement> {
+        override val diagnosticClass get() = MultipleJsExportDefaultInOneFile::class
+    }
+
     interface DelegationByDynamic : KaFirDiagnostic<KtElement> {
         override val diagnosticClass get() = DelegationByDynamic::class
     }
diff --git a/analysis/analysis-api-fir/gen/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KaFirDiagnosticsImpl.kt b/analysis/analysis-api-fir/gen/org/jetbrains/kotlin/analysis/api/fir/diagnostics/KaFirDiagnosticsImpl.kt
@@ -6067,6 +6067,11 @@ internal class NestedJsExportImpl(
     token: KaLifetimeToken,
 ) : KaAbstractFirDiagnostic<KtElement>(firDiagnostic, token), KaFirDiagnostic.NestedJsExport
 
+internal class MultipleJsExportDefaultInOneFileImpl(
+    firDiagnostic: KtPsiDiagnostic,
+    token: KaLifetimeToken,
+) : KaAbstractFirDiagnostic<KtElement>(firDiagnostic, token), KaFirDiagnostic.MultipleJsExportDefaultInOneFile
+
 internal class DelegationByDynamicImpl(
     firDiagnostic: KtPsiDiagnostic,
     token: KaLifetimeToken,
diff --git a/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirWebCommonDiagnosticList.kt b/compiler/fir/checkers/checkers-component-generator/src/org/jetbrains/kotlin/fir/checkers/generator/diagnostics/FirWebCommonDiagnosticList.kt
@@ -49,6 +49,7 @@ object WEB_COMMON_DIAGNOSTICS_LIST : DiagnosticList("FirWebCommonErrors") {
 
     val EXPORT by object : DiagnosticGroup("Export") {
         val NESTED_JS_EXPORT by error<KtElement>()
+        val MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE by error<KtElement>()
     }
 
     val JSCODE by object : DiagnosticGroup("JsCode") {
diff --git a/compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/js/checkers/JsDeclarationCheckers.kt b/compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/js/checkers/JsDeclarationCheckers.kt
@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.fir.analysis.js.checkers
 import org.jetbrains.kotlin.fir.analysis.checkers.declaration.*
 import org.jetbrains.kotlin.fir.analysis.js.checkers.declaration.*
 import org.jetbrains.kotlin.fir.analysis.web.common.checkers.declaration.FirJsExportAnnotationChecker
+import org.jetbrains.kotlin.fir.analysis.web.common.checkers.declaration.FirMultipleJsExportDefaultAnnotationChecker
 import org.jetbrains.kotlin.fir.analysis.web.common.checkers.declaration.FirWebCommonExternalPropertyAccessorChecker
 
 object JsDeclarationCheckers : DeclarationCheckers() {
@@ -60,6 +61,7 @@ object JsDeclarationCheckers : DeclarationCheckers() {
     override val fileCheckers: Set<FirFileChecker>
         get() = setOf(
             FirJsPackageDirectiveChecker,
+            FirMultipleJsExportDefaultAnnotationChecker,
             FirJsNameClashFileTopLevelDeclarationsChecker
         )
 
diff --git a/compiler/fir/checkers/checkers.web.common/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/web/common/FirWebCommonErrors.kt b/compiler/fir/checkers/checkers.web.common/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/web/common/FirWebCommonErrors.kt
@@ -51,6 +51,7 @@ object FirWebCommonErrors : KtDiagnosticsContainer() {
 
     // Export
     val NESTED_JS_EXPORT: KtDiagnosticFactory0 = KtDiagnosticFactory0("NESTED_JS_EXPORT", ERROR, SourceElementPositioningStrategies.DEFAULT, KtElement::class, getRendererFactory())
+    val MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE: KtDiagnosticFactory0 = KtDiagnosticFactory0("MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE", ERROR, SourceElementPositioningStrategies.DEFAULT, KtElement::class, getRendererFactory())
 
     // JsCode
     val JSCODE_ARGUMENT_NON_CONST_EXPRESSION: KtDiagnosticFactory0 = KtDiagnosticFactory0("JSCODE_ARGUMENT_NON_CONST_EXPRESSION", ERROR, SourceElementPositioningStrategies.DEFAULT, KtElement::class, getRendererFactory())
diff --git a/compiler/fir/checkers/checkers.web.common/src/org/jetbrains/kotlin/fir/analysis/diagnostics/web/common/FirWebCommonErrorsDefaultMessages.kt b/compiler/fir/checkers/checkers.web.common/src/org/jetbrains/kotlin/fir/analysis/diagnostics/web/common/FirWebCommonErrorsDefaultMessages.kt
@@ -19,6 +19,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.web.common.FirWebCommonErro
 import org.jetbrains.kotlin.fir.analysis.diagnostics.web.common.FirWebCommonErrors.EXTERNAL_INTERFACE_AS_REIFIED_TYPE_ARGUMENT
 import org.jetbrains.kotlin.fir.analysis.diagnostics.web.common.FirWebCommonErrors.INLINE_EXTERNAL_DECLARATION
 import org.jetbrains.kotlin.fir.analysis.diagnostics.web.common.FirWebCommonErrors.JSCODE_ARGUMENT_NON_CONST_EXPRESSION
+import org.jetbrains.kotlin.fir.analysis.diagnostics.web.common.FirWebCommonErrors.MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.web.common.FirWebCommonErrors.NAMED_COMPANION_IN_EXTERNAL_INTERFACE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.web.common.FirWebCommonErrors.NESTED_CLASS_IN_EXTERNAL_INTERFACE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.web.common.FirWebCommonErrors.NESTED_EXTERNAL_DECLARATION
@@ -77,6 +78,10 @@ object FirWebCommonErrorsDefaultMessages : BaseDiagnosticRendererFactory() {
 
 
         map.put(NESTED_JS_EXPORT, "'@JsExport' is only allowed on files and top-level declarations.")
+        map.put(
+            MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE,
+            "Only one declaration with '@JsExport.Default' is allowed per file."
+        )
 
         map.put(JSCODE_ARGUMENT_NON_CONST_EXPRESSION, "An argument for the 'js()' function must be a constant string expression.")
         map.put(NAMED_COMPANION_IN_EXTERNAL_INTERFACE, "Named companions are not allowed inside external interfaces.")
diff --git a/compiler/fir/checkers/checkers.web.common/src/org/jetbrains/kotlin/fir/analysis/web/common/checkers/declaration/FirMultipleJsExportDefaultAnnotationChecker.kt b/compiler/fir/checkers/checkers.web.common/src/org/jetbrains/kotlin/fir/analysis/web/common/checkers/declaration/FirMultipleJsExportDefaultAnnotationChecker.kt
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2010-2023 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.kotlin.fir.analysis.web.common.checkers.declaration
+
+import org.jetbrains.kotlin.diagnostics.DiagnosticReporter
+import org.jetbrains.kotlin.diagnostics.reportOn
+import org.jetbrains.kotlin.fir.analysis.checkers.MppCheckerKind
+import org.jetbrains.kotlin.fir.analysis.checkers.context.CheckerContext
+import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirBasicDeclarationChecker
+import org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirFileChecker
+import org.jetbrains.kotlin.fir.analysis.checkers.isTopLevel
+import org.jetbrains.kotlin.fir.analysis.diagnostics.web.common.FirWebCommonErrors
+import org.jetbrains.kotlin.fir.declarations.DirectDeclarationsAccess
+import org.jetbrains.kotlin.fir.declarations.FirDeclaration
+import org.jetbrains.kotlin.fir.declarations.FirFile
+import org.jetbrains.kotlin.fir.declarations.getAnnotationByClassId
+import org.jetbrains.kotlin.name.StandardClassIds
+
+object FirMultipleJsExportDefaultAnnotationChecker : FirFileChecker(MppCheckerKind.Common) {
+    @OptIn(DirectDeclarationsAccess::class)
+    context(context: CheckerContext, reporter: DiagnosticReporter)
+    override fun check(declaration: FirFile) {
+        val declarationsWithJsExportDefault = declaration.declarations.filter {
+            it.getAnnotationByClassId(StandardClassIds.Annotations.jsExportDefault, context.session) != null
+        }
+
+        if (declarationsWithJsExportDefault.size > 1) {
+            declarationsWithJsExportDefault.forEach {
+                reporter.reportOn(it.source, FirWebCommonErrors.MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE)
+            }
+        }
+    }
+}
diff --git a/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirNonSuppressibleErrorNames.kt b/compiler/fir/checkers/gen/org/jetbrains/kotlin/fir/analysis/diagnostics/FirNonSuppressibleErrorNames.kt
@@ -798,6 +798,7 @@ val FIR_NON_SUPPRESSIBLE_ERROR_NAMES: Set<String> = setOf(
     "NAMED_COMPANION_IN_EXPORTED_INTERFACE",
     "NOT_EXPORTED_ACTUAL_DECLARATION_WHILE_EXPECT_IS_EXPORTED",
     "NESTED_JS_EXPORT",
+    "MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE",
     "DELEGATION_BY_DYNAMIC",
     "PROPERTY_DELEGATION_BY_DYNAMIC",
     "SPREAD_OPERATOR_IN_DYNAMIC_CALL",
diff --git a/compiler/testData/diagnostics/testsWithJsStdLib/export/wrongExportedDeclaration.fir.kt b/compiler/testData/diagnostics/testsWithJsStdLib/export/wrongExportedDeclaration.fir.kt
@@ -51,14 +51,14 @@ inline class <!WRONG_EXPORTED_DECLARATION("value class")!>B(val b: Int)<!>
 @JsExport
 <!INCOMPATIBLE_MODIFIERS("inline; value")!>inline<!> <!INCOMPATIBLE_MODIFIERS("value; inline")!>value<!> class <!WRONG_EXPORTED_DECLARATION("value class")!>C(val c: Int)<!>
 
-@JsExport.Default
-<!INCOMPATIBLE_MODIFIERS("value; inline")!>value<!> <!INCOMPATIBLE_MODIFIERS("inline; value")!>inline<!> class <!WRONG_EXPORTED_DECLARATION("value class")!>D(val d: Int)<!>
+<!MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE!>@JsExport.Default
+<!INCOMPATIBLE_MODIFIERS("value; inline")!>value<!> <!INCOMPATIBLE_MODIFIERS("inline; value")!>inline<!> class <!WRONG_EXPORTED_DECLARATION("value class")!>D(val d: Int)<!><!>
 
 @JsExport
 external interface ExternalInterface
 
-@JsExport.Default
-external interface DefaultExternalInterface
+<!MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE!>@JsExport.Default
+external interface DefaultExternalInterface<!>
 
 @JsExport
 external enum class <!ENUM_CLASS_IN_EXTERNAL_DECLARATION_WARNING, WRONG_EXPORTED_DECLARATION("external enum class")!>ExternalEnum<!> {
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsES6TypeScriptExportTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsES6TypeScriptExportTestGenerated.java
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsTypeScriptExportTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsTypeScriptExportTestGenerated.java
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsTypeScriptExportWithInlinedFunInKlibTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsTypeScriptExportWithInlinedFunInKlibTestGenerated.java
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsES6TypeScriptExportTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsES6TypeScriptExportTestGenerated.java
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsTypeScriptExportTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrJsTypeScriptExportTestGenerated.java
diff --git a/js/js.translator/testData/typescript-export/js/module-systems-in-exported-file/commonjs.kt b/js/js.translator/testData/typescript-export/js/module-systems-in-exported-file/commonjs.kt
@@ -34,7 +34,8 @@ fun asyncList(): Promise<List<Int>> =
 fun arrayOfLists(): Array<List<Int>> =
     arrayOf(listOf(1, 2))
 
+
 fun acceptArrayOfPairs(array: Array<Pair<String, String>>) {}
 
 @JsExport.Default
-fun justSomeDefaultExport() = "OK"
+fun justSomeDefaultExport() = "OK"
diff --git a/js/js.translator/testData/typescript-export/js/module-systems-in-exported-file/umd.kt b/js/js.translator/testData/typescript-export/js/module-systems-in-exported-file/umd.kt
@@ -20,6 +20,7 @@ class C(val x: Int) {
     fun doubleX() = x * 2
 }
 
+
 fun box(): String = "OK"
 
 @JsExport.Default
diff --git a/libraries/stdlib/common/src/kotlin/JsAnnotationsH.kt b/libraries/stdlib/common/src/kotlin/JsAnnotationsH.kt
@@ -111,8 +111,8 @@ public annotation class ExperimentalJsStatic
 @OptionalExpectation
 public expect annotation class JsExport() {
     /**
-     * The annotation prevents exporting the annotated member of an exported class.
-     * This annotation is experimental, meaning that the restrictions mentioned above are subject to change.
+     * This annotation prevents the annotated member of an exported class from being exported.
+     * It is experimental, meaning the restrictions described above are subject to change.
      */
     @ExperimentalJsExport
     @Retention(AnnotationRetention.BINARY)
@@ -122,17 +122,20 @@ public expect annotation class JsExport() {
     public annotation class Ignore()
 
     /**
-     * The annotation notifies that the exported declaration should be exported as `default` on the JS platform.
-     * It means that for ES modules the annotated declaration will be available under the `default` export.
-     * For CommonJS, UMD, and plain modules the annotated declaration will be available by the name `default`.
-     * This annotation is experimental, meaning that the restrictions mentioned above are subject to change.
+     * This annotation indicates that the exported declaration should be exported as `default` on the JS platform.
      *
-     * Note that if the annotation is applied multiple times across the project, the behavior depends on the compilation granularity.
-     * For whole-program: if inside multiple libs the annotation is applied, it leads to a runtime error.
-     * For per-module: the case with the `whole-program` defaults across dependencies is solved.
-     * However, there will be the same runtime error if the annotation is applied multiple times in a single module.
-     * For per-file: both problems of `whole-program` and `per-module` are solved,
-     * but another one appear if @JsExport.Default applied multiple times in a single file
+     * In ES modules, the annotated declaration is available as the `default` export.
+     * In CommonJS, UMD, and plain modules, the annotated declaration is available under the name `default`.
+     *
+     * This annotation is experimental, meaning that the restrictions described above are subject to change.
+     *
+     * Note: If the annotation is applied multiple times across the project, the behavior depends on the compilation granularity.
+     * 
+     * - **Whole-program compilation**: If multiple libraries apply the annotation, it results in a runtime error.
+     * - **Per-module compilation**: Conflicts across dependencies (like in `whole-program` mode) are resolved.
+     *   However, a runtime error occurs if the annotation is applied multiple times within a single module.
+     * - **Per-file compilation**: This mode resolves the issues present in `whole-program` and `per-module` modes.
+     *   However, a new issue arises if `@JsExport.Default` is applied multiple times within the same file.
      */
     @ExperimentalJsExport
     @Retention(AnnotationRetention.BINARY)
diff --git a/libraries/stdlib/js/src/kotlin/annotationsJs.kt b/libraries/stdlib/js/src/kotlin/annotationsJs.kt
@@ -213,17 +213,20 @@ public actual annotation class JsExport {
 
 
     /**
-     * The annotation notifies that the exported declaration should be exported as `default` on the JS platform.
-     * It means that for ES modules the annotated declaration will be available under the `default` export.
-     * For CommonJS, UMD, and plain modules the annotated declaration will be available by the name `default`.
-     * This annotation is experimental, meaning that the restrictions mentioned above are subject to change.
+     * This annotation indicates that the exported declaration should be exported as `default` on the JS platform.
+     *
+     * In ES modules, the annotated declaration is available as the `default` export.
+     * In CommonJS, UMD, and plain modules, the annotated declaration is available under the name `default`.
+     *
+     * This annotation is experimental, meaning that the restrictions described above are subject to change.
      *
-     * Note that if the annotation is applied multiple times across the project, the behavior depends on the compilation granularity.
-     * For whole-program: if inside multiple libs the annotation is applied, it leads to a runtime error.
-     * For per-module: the case with the `whole-program` defaults across dependencies is solved.
-     * However, there will be the same runtime error if the annotation is applied multiple times in a single module.
-     * For per-file: both problems of `whole-program` and `per-module` are solved,
-     * but another one appear if @JsExport.Default applied multiple times in a single file
+     * Note: If the annotation is applied multiple times across the project, the behavior depends on the compilation granularity.
+     * 
+     * - **Whole-program compilation**: If multiple libraries apply the annotation, it results in a runtime error.
+     * - **Per-module compilation**: Conflicts across dependencies (like in `whole-program` mode) are resolved.
+     *   However, a runtime error occurs if the annotation is applied multiple times within a single module.
+     * - **Per-file compilation**: This mode resolves the issues present in `whole-program` and `per-module` modes.
+     *   However, a new issue arises if `@JsExport.Default` is applied multiple times within the same file.
      */
     @ExperimentalJsExport
     @Retention(AnnotationRetention.BINARY)
diff --git a/libraries/stdlib/wasm/js/src/kotlin/js/annotations.kt b/libraries/stdlib/wasm/js/src/kotlin/js/annotations.kt
@@ -28,17 +28,20 @@ public actual annotation class JsExport {
 
 
     /**
-     * The annotation notifies that the exported declaration should be exported as `default` on the JS platform.
-     * It means that for ES modules the annotated declaration will be available under the `default` export.
-     * For CommonJS, UMD, and plain modules the annotated declaration will be available by the name `default`.
-     * This annotation is experimental, meaning that the restrictions mentioned above are subject to change.
+     * This annotation indicates that the exported declaration should be exported as `default` on the JS platform.
      *
-     * Note that if the annotation is applied multiple times across the project, the behavior depends on the compilation granularity.
-     * For whole-program: if inside multiple libs the annotation is applied, it leads to a runtime error.
-     * For per-module: the case with the `whole-program` defaults across dependencies is solved.
-     * However, there will be the same runtime error if the annotation is applied multiple times in a single module.
-     * For per-file: both problems of `whole-program` and `per-module` are solved,
-     * but another one appear if @JsExport.Default applied multiple times in a single file
+     * In ES modules, the annotated declaration is available as the `default` export.
+     * In CommonJS, UMD, and plain modules, the annotated declaration is available under the name `default`.
+     *
+     * This annotation is experimental, meaning that the restrictions described above are subject to change.
+     *
+     * Note: If the annotation is applied multiple times across the project, the behavior depends on the compilation granularity.
+     * 
+     * - **Whole-program compilation**: If multiple libraries apply the annotation, it results in a runtime error.
+     * - **Per-module compilation**: Conflicts across dependencies (like in `whole-program` mode) are resolved.
+     *   However, a runtime error occurs if the annotation is applied multiple times within a single module.
+     * - **Per-file compilation**: This mode resolves the issues present in `whole-program` and `per-module` modes.
+     *   However, a new issue arises if `@JsExport.Default` is applied multiple times within the same file.
      */
     @ExperimentalJsExport
     @Retention(AnnotationRetention.BINARY)
diff --git a/libraries/tools/binary-compatibility-validator/klib-public-api/kotlin-stdlib.api b/libraries/tools/binary-compatibility-validator/klib-public-api/kotlin-stdlib.api

Original file line number	Diff line number	Diff line change
`@@ -7211,6 +7211,12 @@ internal val KT_DIAGNOSTIC_CONVERTER = KaDiagnosticConverterBuilder.buildConvert`
`7211`	`7211`	`token,`
`7212`	`7212`	`)`
`7213`	`7213`	`}`
	`7214`	`+ add(FirWebCommonErrors.MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE) { firDiagnostic ->`
	`7215`	`+ MultipleJsExportDefaultInOneFileImpl(`
	`7216`	`+ firDiagnostic as KtPsiDiagnostic,`
	`7217`	`+ token,`
	`7218`	`+ )`
	`7219`	`+ }`
`7214`	`7220`	`add(FirJsErrors.DELEGATION_BY_DYNAMIC) { firDiagnostic ->`
`7215`	`7221`	`DelegationByDynamicImpl(`
`7216`	`7222`	`firDiagnostic as KtPsiDiagnostic,`
Original file line number	Diff line number	Diff line change
`@@ -5045,6 +5045,10 @@ sealed interface KaFirDiagnostic<PSI : PsiElement> : KaDiagnosticWithPsi<PSI> {`
`5045`	`5045`	`override val diagnosticClass get() = NestedJsExport::class`
`5046`	`5046`	`}`
`5047`	`5047`
	`5048`	`+ interface MultipleJsExportDefaultInOneFile : KaFirDiagnostic<KtElement> {`
	`5049`	`+ override val diagnosticClass get() = MultipleJsExportDefaultInOneFile::class`
	`5050`	`+ }`
	`5051`	`+`
`5048`	`5052`	`interface DelegationByDynamic : KaFirDiagnostic<KtElement> {`
`5049`	`5053`	`override val diagnosticClass get() = DelegationByDynamic::class`
`5050`	`5054`	`}`
Original file line number	Diff line number	Diff line change
`@@ -49,6 +49,7 @@ object WEB_COMMON_DIAGNOSTICS_LIST : DiagnosticList("FirWebCommonErrors") {`
`49`	`49`
`50`	`50`	`val EXPORT by object : DiagnosticGroup("Export") {`
`51`	`51`	`val NESTED_JS_EXPORT by error<KtElement>()`
	`52`	`+ val MULTIPLE_JS_EXPORT_DEFAULT_IN_ONE_FILE by error<KtElement>()`
`52`	`53`	`}`
`53`	`54`
`54`	`55`	`val JSCODE by object : DiagnosticGroup("JsCode") {`