From e49dffc9ece86bddf094b9ad4ad15eb4856d6277 Mon Sep 17 00:00:00 2001
From: Evan You <yyx990803@gmail.com>
Date: Mon, 27 Nov 2023 18:10:00 +0800
Subject: [PATCH] fix(parser): directive arg should be undefined on shorthands
 with no arg

---
 packages/compiler-core/__tests__/parse.spec.ts | 11 +++++++++++
 packages/compiler-core/src/parser.ts           |  1 +
 2 files changed, 12 insertions(+)

diff --git a/packages/compiler-core/__tests__/parse.spec.ts b/packages/compiler-core/__tests__/parse.spec.ts
index 7eb5a000e5e..a116d22c148 100644
--- a/packages/compiler-core/__tests__/parse.spec.ts
+++ b/packages/compiler-core/__tests__/parse.spec.ts
@@ -1941,6 +1941,17 @@ describe('compiler: parse', () => {
     })
   })
 
+  test('arg should be undefined on shorthand dirs with no arg', () => {
+    const ast = baseParse(`<template #></template>`)
+    const el = ast.children[0] as ElementNode
+    expect(el.props[0]).toMatchObject({
+      type: NodeTypes.DIRECTIVE,
+      name: 'slot',
+      exp: undefined,
+      arg: undefined
+    })
+  })
+
   describe('decodeEntities option', () => {
     test('use decode by default', () => {
       const ast: any = baseParse('&gt;&lt;&amp;&apos;&quot;&foo;')
diff --git a/packages/compiler-core/src/parser.ts b/packages/compiler-core/src/parser.ts
index 9effa0250e3..4e3c21480a2 100644
--- a/packages/compiler-core/src/parser.ts
+++ b/packages/compiler-core/src/parser.ts
@@ -238,6 +238,7 @@ const tokenizer = new Tokenizer(stack, {
   },
 
   ondirarg(start, end) {
+    if (start === end) return
     const arg = getSlice(start, end)
     if (inVPre) {
       ;(currentProp as AttributeNode).name += arg