From a2e444628432b4782f035e71bcb678638703d228 Mon Sep 17 00:00:00 2001
From: MukjepScarlet <93977077+MukjepScarlet@users.noreply.github.com>
Date: Mon, 27 Jan 2025 00:45:05 +0800
Subject: [PATCH] FunctionalInterface annotation for JVM1.8+ on Kotlin
 functions

All Java built-in function types like `BiFunction`, `IntProvider` have this annotation. Also, this annotation is used by the GraalVM Polyglot library. It can only parse types with this annotation to a JavaScript function, that's why I want to add this.
---
 generators/builtins/functions.kt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/generators/builtins/functions.kt b/generators/builtins/functions.kt
index 7670a0d856486..8cd1c5edd9b91 100644
--- a/generators/builtins/functions.kt
+++ b/generators/builtins/functions.kt
@@ -45,7 +45,7 @@ class GenerateFunctions(out: PrintWriter) : BuiltInsSourceGenerator(out) {
     override fun generateBody() {
         for (i in 0..MAX_PARAM_COUNT) {
             generateDocumentation(i)
-            out.print("public interface Function$i")
+            out.print("@FunctionalInterface public interface Function$i")
             generateTypeParameters(i, variance = true)
             generateSuperClass()
             generateFunctionClassBody(i)