Should upgrade acorn's ecmascript version

[hackape]

Describe the bug

Discovered when resolving a stackoverflow question.

Svelte-kit optimistically sets tsconfig.json -> compilerOptions.target = "esnext" which now become ES2022, but svelte/compiler is still using ecmaVersion: 12 aka ES2021, thus any ES2022 language feature will trigger Unexpected Token acorn error.

So it's either:

• svelte-kit set tsconfig.json -> compilerOptions.target = "ES2021"
• or, mod svelte/src/compiler/parse/acorn.ts

export const parse = (source: string): Node => code_red.parse(source, {
	sourceType: 'module',
	ecmaVersion: 'latest',
	locations: true
});

I haven't spent time reviewing internal of svelte/compiler module, it's unclear if updating AST to ES2022 will break things. Guess change made on svelte-kit's part is easier path for now, but in the long run ES upgrade need some attention.

Reproduction

Any component that uses latest ES2022 language feature will trigger the bug.

<script>
let name = 'world';
class Greeter {
    greeting; // class field declaration
}
</script>

<h1>Hello {name}!</h1>

Logs

No response

System Info

irrelevant

Severity

blocking an upgrade

[jasonlyu123]

Duplicate of #6900, #6592. There's still AST printing needed to be implemented.