fix(eslint-plugin): [no-unused-expressions] false negatives when using assertions

[up201304504]

PR Checklist

• Addresses an existing open issue: fixes Bug: [no-unused-expressions] False negatives when using assertions. #8654
• That issue was marked as accepting prs
• Steps in Contributing were taken

Overview

The no-unused-expressions rule was producing false negatives when assertions are used within TypeScript code:

• TSAsExpression
• TSNonNullExpression
• TSTypeAssertion

This pull request resolves the identified bug by correcting the behavior of the no-unused-expressions rule. The changes made in this PR have been validated in the TypeScript playground:

[typescript-eslint]

Thanks for the PR, @up201304504!

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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✅ Successfully ran 31 targets

• nx test eslint-plugin
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• nx test typescript-eslint
• nx test typescript-estree
• nx test utils
• nx run types:build
• nx test scope-manager
• nx test type-utils
• nx test visitor-keys
• nx run repo-tools:postinstall-script
• nx test rule-schema-to-typescript-types
• nx test parser
• nx run-many --target=build --parallel --exclude=website --exclude=website-eslint
• nx test repo-tools
• nx test ast-spec
• nx test eslint-plugin-internal
• nx run-many --target=lint --parallel --exclude eslint-plugin
• nx run-many --target=typecheck --parallel
• nx test typescript-eslint --coverage=false
• nx test rule-schema-to-typescript-types --coverage=false
• nx test type-utils --coverage=false
• nx test scope-manager --coverage=false
• nx test repo-tools --coverage=false
• nx test parser --coverage=false
• nx test visitor-keys --coverage=false
• nx test eslint-plugin-internal --coverage=false
• nx test ast-spec --coverage=false
• nx test typescript-estree --coverage=false
• nx test utils --coverage=false
• nx run repo-tools:generate-configs
• nx run integration-tests:test

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.24%. Comparing base (994812b) to head (dc3a949).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8668      +/-   ##
==========================================
- Coverage   88.02%   87.24%   -0.79%     
==========================================
  Files         401      251     -150     
  Lines       13934    12336    -1598     
  Branches     4087     3882     -205     
==========================================
- Hits        12265    10762    -1503     
+ Misses       1370     1305      -65     
+ Partials      299      269      -30     

Flag	Coverage Δ
unittest	87.24% <100.00%> (-0.79%)	⬇️

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

Files	Coverage Δ
...s/eslint-plugin/src/rules/no-unused-expressions.ts	95.65% <100.00%> (+0.41%)	⬆️

... and 150 files with indirect coverage changes

[auvred]

Nice start! 🚀

The code changes look good to me. I'm requesting one change in tests.

[auvred]

🚀 LGTM! Thanks for working on this!

[JoshuaKGoldberg]

🔥 thanks!