[Bug]: async(x?) should throw

[tony-go]

💻

• Would you like to work on a fix?

How are you using Babel?

Programmatic API (babel.transform, babel.parse)

Input code

async(x?) // it should throw

REPL

Configuration file name

No response

Configuration

No response

Current and expected behavior

Current: the input is parsed correctly

Expected: it should throw a Unexpected end of input (with the token position of course)

Environment

• Babel version: 7.14.4
• Electron: 1.8
• Node: 10.3

Possible solution

No response

Additional context

No response

[babel-bot]

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[nicolo-ribaudo]

We should also check that just (x?); throws.

[JLHwung]

For reference, Babel does not throw on unambiguous call expression when either flow or typescript plugin is enabled.

asyn(c?)

REPL.

[tony-go]

Once #13419 is merged I switch to this one ^^

[tony-go]

Hi @JLHwung and @nicolo-ribaudo 👋

It's a bit funny but is seems that on the version 7.14.5 it works 😆

I also check that it doesn't throw with typescript and flow. But I let you double check.

[tony-go]

@JLHwung Maybe we fix it in our previous fix...

[nicolo-ribaudo]

Well, it should throw when Flow or TS are enabled 😛

[JLHwung]

Can confirm it is fixed in #13419 . Because the checking logic was moved to checkExpressionErrors and we have already invoked checkExpressionErrors when parsing async call:

babel/packages/babel-parser/src/parser/expression.js

Line 796 in 47ad54a

this.checkExpressionErrors(refExpressionErrors, true);

[nicolo-ribaudo]

Oh we should still add a test then.

[tony-go]

I'll add it so :)