fix: 関数の引数の初期値内に不正なreturn文がある場合に文法エラーにならない問題を修正 (#977)

* 関数の引数の初期値内に不正なreturn文がある場合に文法エラーにならない問題を修正

* 1.1.2

* npm version patch && npm run pre-release

* npm run api

Author: takejohn

CHANGELOG.md

@@ -1,5 +1,9 @@
 [Read translated version (en)](./translations/en/CHANGELOG.md)
 
+# 1.1.2
+
+- Fix: 関数の引数の初期値内に不正なreturn文がある場合に文法エラーにならない問題を修正
+
 # 1.1.1
 
 - Fix: オブジェクトリテラルのプロパティ名に一部の予約語を記述できなかった問題を修正

etc/aiscript.api.md

@@ -21,7 +21,7 @@ type AddAssign = NodeBase & {
 };
 
 // @public (undocumented)
-export const AISCRIPT_VERSION: "1.1.0";
+export const AISCRIPT_VERSION: "1.1.2";
 
 // @public (undocumented)
 abstract class AiScriptError extends Error {

package-lock.json

@@ -1,7 +1,7 @@
 {
 	"type": "module",
 	"name": "@syuilo/aiscript",
-	"version": "1.1.1",
+	"version": "1.1.2",
 	"description": "AiScript implementation",
 	"author": "syuilo <syuilotan@yahoo.co.jp>",
 	"license": "MIT",

package.json

@@ -3,6 +3,19 @@ import { AiScriptSyntaxError } from '../../error.js';
 
 import type * as Ast from '../../node.js';
 
+function getClosestAncestorFunction(node: Ast.Return, ancestors: Ast.Node[]): Ast.Fn | undefined {
+	let child: Ast.Node = node;
+	for (let i = ancestors.length - 1; i >= 0; i--) {
+		const ancestor = ancestors[i]!;
+		// return文が関数のデフォルト引数の中にある場合は、今見つかった関数ではなくさらに上の関数がこのreturn文に対応する。
+		if (ancestor.type === 'fn' && !ancestor.params.some((param) => param.default != null && param.default === child)) {
+			return ancestor;
+		}
+		child = ancestor;
+	}
+	return;
+}
+
 function getCorrespondingBlock(ancestors: Ast.Node[], label?: string): Ast.Each | Ast.For | Ast.Loop | Ast.If | Ast.Match | Ast.Block | undefined {
 	for (let i = ancestors.length - 1; i >= 0; i--) {
 		const ancestor = ancestors[i]!;
@@ -33,7 +46,8 @@ function getCorrespondingBlock(ancestors: Ast.Node[], label?: string): Ast.Each
 function validateNode(node: Ast.Node, ancestors: Ast.Node[]): Ast.Node {
 	switch (node.type) {
 		case 'return': {
-			if (!ancestors.some(({ type }) => type === 'fn')) {
+			const closestAncestorFunction = getClosestAncestorFunction(node, ancestors);
+			if (closestAncestorFunction === undefined) {
 				throw new AiScriptSyntaxError('return must be inside function', node.loc.start);
 			}
 			break;

src/parser/plugins/validate-jump-statements.ts

@@ -1,6 +1,6 @@
 import * as assert from 'assert';
 import { describe, test } from 'vitest';
-import { utils } from '../src';
+import { errors, utils } from '../src';
 import { NUM, STR, NULL, ARR, OBJ, BOOL, TRUE, FALSE, ERROR ,FN_NATIVE } from '../src/interpreter/value';
 import { AiScriptRuntimeError, AiScriptSyntaxError } from '../src/error';
 import { exe, getMeta, eq } from './testutils';
@@ -481,7 +481,8 @@ describe('return', () => {
 		<: f()
 		`);
 		eq(res, NUM(1));
-		await assert.rejects(() => exe('<: @(x = eval { return 1 }){}'));
+		await assert.rejects(() => exe('<: @(x = eval { return 1 }){}'), errors.AiScriptSyntaxError);
+		await assert.rejects(() => exe('<: @(a = @(b = eval { return 0 }){}){}'), errors.AiScriptSyntaxError);
 	});
 
 	test.concurrent('in template', async () => {