feat(eslint-plugin): add allowNever support to restrict-template-expressions

[domdomegg]

PR Checklist

• Addresses an existing open issue: fixes Enhancement: [restrict-template-expressions] allow expressions with never type #5325
• That issue was marked as accepting prs
• Steps in Contributing were taken

Overview

Adds allowNever support, which makes doing things like exhaustive switching easier. Uses the existing utils in the same way as allowAny does, and have added relevant and realistic tests.

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✅ Successfully ran 45 targets

• Node 18 - nx test eslint-plugin
• Node 14 - nx test eslint-plugin --coverage=false
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[typescript-eslint]

Thanks for the PR, @domdomegg!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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[codecov]

Codecov Report

Merging #6554 (0a97df7) into main (9eafd87) will increase coverage by 0.02%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6554      +/-   ##
==========================================
+ Coverage   85.15%   85.17%   +0.02%     
==========================================
  Files         383      383              
  Lines       13026    13035       +9     
  Branches     3839     3841       +2     
==========================================
+ Hits        11092    11103      +11     
+ Misses       1572     1570       -2     
  Partials      362      362              

Flag	Coverage Δ
unittest	85.17% <100.00%> (+0.02%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...-plugin/src/rules/restrict-template-expressions.ts	100.00% <100.00%> (ø)

... and 8 files with indirect coverage changes

[domdomegg]

Hey @bradzacher - I think this PR is good to go but the 'Website tests' build is failing due to Netlify not being ready. I don't think I've changed anything meaningful here, and it seems also to be failing on main. I'm wary that the query listed in the contributing docs filters out this PR because of the failing status, and wanted to check this could still get reviewed.

(apologies if you're the wrong person to ping - couldn't find a doc on process for these kinds of questions in the contributing docs)

[JoshuaKGoldberg]

Looks nice and clean, thanks for sending this in @domdomegg! Just blocking on adding more tests (or pointing me to where I've missed them). 🚀

[JoshuaKGoldberg]

'Website tests' build is failing due to Netlify not being ready.

Blurgh, yeah, this is unfortunate. #6508. Don't worry about it - it's out of your control and unrelated to this PR.

(apologies if you're the wrong person to ping - couldn't find a doc on process for these kinds of questions in the contributing docs)

Looks like we need to clarify that! Thanks for mentioning @domdomegg 😄. Just filed #6584:

Today, the right step is to just post a comment. You don't need to tag anybody - we'll see it regardless of the tag (the joy and pain of GitHub notifications 🥲). One of us will drop by and help when we can.

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✅ Successfully ran 25 targets

• Node 18 - nx test eslint-plugin
• Node 14 - nx test eslint-plugin --coverage=false
• Node 18 - nx test visitor-keys
• Node 18 - nx run-many --target=build --parallel --exclude website
• Node 18 - nx test typescript-estree
• Node 18 - nx test utils
• Node 18 - nx test type-utils
• Node 18 - nx test parser
• Node 18 - nx test eslint-plugin-tslint
• Node 18 - nx test scope-manager
• Node 18 - nx test eslint-plugin-internal
• Node 14 - nx test utils --coverage=false
• Node 14 - nx run-many --target=build --parallel --exclude website
• Node 18 - nx test ast-spec
• Node 14 - nx test visitor-keys --coverage=false
• Node 14 - nx test type-utils --coverage=false
• Node 14 - nx test typescript-estree --coverage=false
• nx run-many --target=typecheck --parallel
• Node 14 - nx test scope-manager --coverage=false
• Node 14 - nx test parser --coverage=false
• nx run-many --target=lint --parallel
• Node 14 - nx test ast-spec --coverage=false
• Node 14 - nx test eslint-plugin-tslint --coverage=false
• nx run-many --target=build --parallel --exclude website
• Node 14 - nx test eslint-plugin-internal --coverage=false

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[JoshuaKGoldberg]

Super, thanks @domdomegg! ✨

[JoshuaKGoldberg]

Err, once the unit test failure is resolved, that is*

https://github.com/typescript-eslint/typescript-eslint/actions/runs/4420331029/jobs/7749934631?pr=6554

Summary of all failing tests
 FAIL  tests/rules/restrict-template-expressions.test.ts
  ● restrict-template-expressions › invalid › 
        declare const value: never;
        const stringy = `${value}`;
      
    assert.strictEqual(received, expected)
    Expected value to strictly be equal to:
      26
    Received:
      28
    
    Message:
      Error column should be 26

[JoshuaKGoldberg]

awesome! Thanks @domdomegg!