From 2fa69c89e64e7431cb00c29783298f3141fd976a Mon Sep 17 00:00:00 2001
From: FineArchs <133759614+FineArchs@users.noreply.github.com>
Date: Fri, 26 Apr 2024 18:42:15 +0900
Subject: [PATCH 1/3] Update index.ts

---
 src/interpreter/index.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/interpreter/index.ts b/src/interpreter/index.ts
index 23df41ea..496e16ff 100644
--- a/src/interpreter/index.ts
+++ b/src/interpreter/index.ts
@@ -239,7 +239,7 @@ export class Interpreter {
 			for (let i = 0; i < (fn.args ?? []).length; i++) {
 				_args.set(fn.args![i]!, {
 					isMutable: true,
-					value: args[i]!,
+					value: args[i] ?? NULL,
 				});
 			}
 			const fnScope = fn.scope!.createChildScope(_args);

From d8df50fcc9de652f7e59a1515af04077371ea0ba Mon Sep 17 00:00:00 2001
From: FineArchs <133759614+FineArchs@users.noreply.github.com>
Date: Fri, 26 Apr 2024 18:46:25 +0900
Subject: [PATCH 2/3] add test

---
 test/index.ts | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/test/index.ts b/test/index.ts
index 290efa73..07e8385c 100644
--- a/test/index.ts
+++ b/test/index.ts
@@ -1296,6 +1296,16 @@ describe('Function call', () => {
 		}
 		assert.fail();
 	});
+
+	test.concurrent('omitted args', async () => {
+		const res = await exe(`
+		@f(x, y) {
+			[x, y]
+		}
+		<: f(1)
+		`);
+		eq(res, ARR([NUM(1), NULL]));
+	});
 });
 
 describe('Return', () => {

From a7178576257cffa032503089d95611ff25a598fb Mon Sep 17 00:00:00 2001
From: FineArchs <133759614+FineArchs@users.noreply.github.com>
Date: Fri, 26 Apr 2024 18:54:59 +0900
Subject: [PATCH 3/3] Update CHANGELOG.md

---
 CHANGELOG.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0fabbc0d..e0523285 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,8 @@
 [Read translated version (en)](./translations/en/CHANGELOG.md)
 
 # 未リリース分
+- 関数の省略された引数にNULLを格納するように
+  - 一時的な措置であり、省略可能引数構文の実装と同時に廃止予定です。依存し過ぎないようにしてください
 
 # 0.18.0
 - `Core:abort`でプログラムを緊急停止できるように