Type annotations not working in Svelte's HTML template section

[ptrxyz]

Before You File a Bug Report Please Confirm You Have Done The Following...

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.

What version of ESLint are you using?

8.23.1

What version of eslint-plugin-svelte are you using?

2.8.0

What did you do?

Configuration

module.exports = {
	root: true,
	parser: '@typescript-eslint/parser',
	extends: [
		'eslint:recommended',
		'plugin:@typescript-eslint/recommended',
		'plugin:@typescript-eslint/recommended-requiring-type-checking',
		'plugin:import/recommended',
		'plugin:import/typescript',
		'plugin:svelte/recommended',
		'plugin:svelte/prettier',
		'prettier'
	],
	plugins: ['unused-imports', '@typescript-eslint', 'import'],
	ignorePatterns: ['*.cjs', 'svelte.config.js', 'tailwind.config.cjs', 'postcss.config.cjs'],
	overrides: [
		{
			files: ['*.svelte'],
			parser: 'svelte-eslint-parser',
			parserOptions: {
				parser: '@typescript-eslint/parser'
			}
		}
	],
	settings: {
		'svelte3/typescript': () => require('typescript'),
		'import/resolver': { typescript: {} },
		'import/parsers': { '@typescript-eslint/parser': ['.ts', '.tsx'] }
	},
	parserOptions: {
		sourceType: 'module',
		ecmaVersion: 2020,
		project: ['./tsconfig.json'],
		extraFileExtensions: ['.svelte']
	},
	env: {
		browser: true,
		es2017: true,
		node: true
	},
	rules: {
		'no-unused-vars': 'off',
		'@typescript-eslint/no-unused-vars': 'off',
		'unused-imports/no-unused-vars': [
			'warn',
			{ vars: 'all', varsIgnorePattern: '^_', args: 'after-used', argsIgnorePattern: '^_' }
		],
		'unused-imports/no-unused-imports': 'error'
	}
}

<script lang="ts">
// this works:
const something = (e:any) => e
</script>

<!-- this does not -->
<div on:click={(e : any) => e}>Click</div>

What did you expect to happen?

I expect on:click={(e : any) => e} on the div to work.

What actually happened?

eslint complains that the : would be an unexpected token. As soon as I remove the type annotations, things work great.

Parsing error: Unexpected token (eslint)

Link to Minimal Reproducible Example

EXAMPLE

Additional comments

No response

[JounQin]

Is that valid syntax for Svelte itself?

[ptrxyz]

Hm, good question. 🤔
But I just found this: sveltejs/svelte#5403
Could it be that it's not...?

[ota-meshi]

Svelte's compiler does not allow TypeScript inside HTML templates.
Please follow sveltejs/svelte#4701.