diff --git a/java/java-syntax/src/com/intellij/java/syntax/element/JavaLanguageLevelProvider.kt b/java/java-syntax/src/com/intellij/java/syntax/element/JavaLanguageLevelProvider.kt
index 12815dfb5775..8f61990ec326 100644
--- a/java/java-syntax/src/com/intellij/java/syntax/element/JavaLanguageLevelProvider.kt
+++ b/java/java-syntax/src/com/intellij/java/syntax/element/JavaLanguageLevelProvider.kt
@@ -12,7 +12,7 @@ import org.jetbrains.annotations.ApiStatus
  * Implement this extension point to provide the custom language level for Java lazy parsers.
  */
 @ApiStatus.OverrideOnly
-interface JavaLanguageLevelProvider {
+fun interface JavaLanguageLevelProvider {
   fun getLanguageLevel(node: SyntaxNode): LanguageLevel
 }