diff --git a/compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/js/checkers/declaration/FirJsInheritanceClassChecker.kt b/compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/js/checkers/declaration/FirJsInheritanceClassChecker.kt
index 0ae1bdbd7f4..01188ba222f 100644
--- a/compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/js/checkers/declaration/FirJsInheritanceClassChecker.kt
+++ b/compiler/fir/checkers/checkers.js/src/org/jetbrains/kotlin/fir/analysis/js/checkers/declaration/FirJsInheritanceClassChecker.kt
@@ -18,6 +18,7 @@ import org.jetbrains.kotlin.fir.analysis.checkers.unsubstitutedScope
 import org.jetbrains.kotlin.fir.analysis.diagnostics.js.FirJsErrors
 import org.jetbrains.kotlin.fir.analysis.js.checkers.isOverridingExternalWithOptionalParams
 import org.jetbrains.kotlin.fir.declarations.FirClass
+import org.jetbrains.kotlin.fir.declarations.fullyExpandedClass
 import org.jetbrains.kotlin.fir.declarations.utils.isEffectivelyExternal
 import org.jetbrains.kotlin.fir.declarations.utils.isExpect
 import org.jetbrains.kotlin.fir.declarations.utils.superConeTypes
@@ -48,7 +49,7 @@ sealed class FirJsInheritanceClassChecker(mppKind: MppCheckerKind) : FirClassChe
         if (isEffectivelyExternal && declaration.classKind != ClassKind.ANNOTATION_CLASS) {
             val superTypes = declaration.superConeTypes
                 .filterNot { it.isAnyOrNullableAny || it.isThrowableOrNullableThrowable || it.isEnum }
-                .mapNotNull { it.toSymbol(session) }
+                .mapNotNull { it.toSymbol(session)?.fullyExpandedClass(session) }
 
             if (superTypes.any { !it.isEffectivelyExternal(session) }) {
                 reporter.reportOn(declaration.source, FirJsErrors.EXTERNAL_TYPE_EXTENDS_NON_EXTERNAL_TYPE, context)
diff --git a/compiler/testData/diagnostics/testsWithJsStdLib/externalTypeInheritsExternalTypeViaTypeAlias.fir.kt b/compiler/testData/diagnostics/testsWithJsStdLib/externalTypeInheritsExternalTypeViaTypeAlias.fir.kt
deleted file mode 100644
index 062c3099898..00000000000
--- a/compiler/testData/diagnostics/testsWithJsStdLib/externalTypeInheritsExternalTypeViaTypeAlias.fir.kt
+++ /dev/null
@@ -1,5 +0,0 @@
-external interface Base
-
-typealias TypeAlias = Base
-
-external interface <!EXTERNAL_TYPE_EXTENDS_NON_EXTERNAL_TYPE!>Derived<!>: TypeAlias
diff --git a/compiler/testData/diagnostics/testsWithJsStdLib/externalTypeInheritsExternalTypeViaTypeAlias.kt b/compiler/testData/diagnostics/testsWithJsStdLib/externalTypeInheritsExternalTypeViaTypeAlias.kt
index c3817b13072..6c906368aea 100644
--- a/compiler/testData/diagnostics/testsWithJsStdLib/externalTypeInheritsExternalTypeViaTypeAlias.kt
+++ b/compiler/testData/diagnostics/testsWithJsStdLib/externalTypeInheritsExternalTypeViaTypeAlias.kt
@@ -1,3 +1,5 @@
+// FIR_IDENTICAL
+
 external interface Base
 
 typealias TypeAlias = Base