@babel/types 7.12.11 causes syntax error on TypeScript 3.2.4

[miestr]

Bug Report

Current behavior
I use babel in a react application. When trying to produce a build (yarn run build), it fails with error code:
TypeScript error in /var/jenkins/.../node_modules/@babel/types/lib/index.d.ts(1450,50):
'{' or ';' expected. TS1144

      1448 | }): ReturnedChild[];
      1449 | 
    > 1450 | declare function assertNode(node?: any): asserts node is Node;
           |                                                  ^
      1451 | 

As a current fix I declared a yarn resolution to use version 7.12.10, which compiles without any issues.

- Babel version:  v7.12.11
- Node 10.15.3, yarn 1.22.4, typescript 3.2.4
- OS: Windows 10
- How you are using Babel: webpack
- ```

[babel-bot]

Hey @miestr! We really appreciate you taking the time to report an issue. The collaborators on this project attempt to help as many people as possible, but we're a limited number of volunteers, so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack community that typically always has someone willing to help. You can sign-up here for an invite."

[miestr]

Thank you for your reply! I am using typescript version 3.2.4, as mentioned in the description. чт, 17 дек. 2020 г. в 12:12, Nicolò Ribaudo <notifications@github.com>:

…

Thanks for the bug report! It's the second like this we get, but I cannot reproduce it on the TS playground with any TS version >= 3.7 ( and for older versions we provide a different dts file). What tsc version are you using? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#12519 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AFOS6NEJQLR3I3KLT3WJ3PDSVHRSFANCNFSM4U7KMTPA> .

[nicolo-ribaudo]

(I deleted my reply as soon as I posted it because I noticed you already mentioned it 😅)

We specify typesVersions in out package.json (https://unpkg.com/browse/@babel/types@7.12.11/package.json), so I'm surprised that TS is reading that index.d.ts file 🤔

[JLHwung]

I think typeVersions does not work on legacy typescript versions. There was the reason why we specified >3.7 before 7.12.11.

[AviVahl]

IIRC ts@3.2's support for typeVersions was kinda broken. The thing is, even DefinitelyTyped dropped support for that version already, per https://github.com/DefinitelyTyped/DefinitelyTyped#older-versions-of-typescript-31-and-earlier allowing them to start using that feature more widespread, as all supported ts versions of DT now handle typeVersions properly.

[nicolo-ribaudo]

I have a fix for this, I will open a PR when I get home later (the code is already there, but I just turned off the PC 😛).

I was surprised because typesVersions has been introduced in 3.1, and the OP is using 3.2.

[AviVahl]

@salvoravida
You can avoid your CI breaking by using lock files and not picking up new versions automatically... Lock files are there so we can continue working while addressing any compatibility issues that rise due to new versions. Works well for my team.

I cannot imagine working on a project using ts@3.2 without lock files. It could break at any second due to @types packages already dropping their support. @babel is just the current victim/offender.

[nicolo-ribaudo]

@salvoravida Every time you comment in this repository you do so sarcastically, pretending we owe you something (hint: we do not!). Unless you want to be collaborative, you are not welcome to interact in this repository.

PS. I already recommended you to use lockfiles.

[sawo]

It might sound silly, but as soon as I reformatted the index.d.ts file and the function declarations broke into multiple lines,
the errors disappeared and I was able to compile.

[nicolo-ribaudo]

As another workaround until we release a fix, you can copy the contents of @babel/types/lib/index-ts3.7.d.ts into @babel/types/lib/index.d.ts.

[DJmRek]

Guys you saved me today! Had a similar error cause by typescript 3.4.5 and @bable/types. Thanks
/sparkle @nicolo-ribaudo
/sparkle @AviVahl

[mihanizm56]

get a temp

fix by providing the oldest version in "resolutions" field in package.json
awaiting for the fix
ts version 3.6.4
cra v3.4.3 with --typescript