Before You File a Bug Report Please Confirm You Have Done The Following...

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I havesearched for related issues and found none that matched my issue.
• I haveread the FAQ and my problem is not listed.

Playground Link

https://typescript-eslint.io/play/#ts=5.2.2&fileType=.tsx&code=CYUwxgNghgTiAEYD2A7AzgF3hgXNmArggD7wEqgBmAliiMANwBQTA9K-GgBZIETDxK0AOZNqleAAoMASngBvFgF8WoSLATJ0WSnkpQIaEmQogadRi3bxgSEGkEixEyZTmKmSoA&eslintrc=N4KABGBEBOCuA2BTAzpAXGUEKQAIBcBPABxQGNoBLY-AWhXkoDt8B6ZfKsugIwHs%2BSAIZN6AD2LQUySnyaoMkAO5DoTSODABfEFqA&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkJemy0eAcgK6qoDCAFutAGsylBm3TgwAXxCSgA&tokens=false

Repro Code

declareconstt:true|undefined;if(t){}

ESLint Config

module.exports={"rules":{"@typescript-eslint/strict-boolean-expressions":"warn"}}

tsconfig

{"compilerOptions": {"strictNullChecks":true  }}

Expected Result

I expect that the conditional should be flagged as a nullable boolean.

Actual Result

no report.

Additional Info

By contrast,false | undefined andboolean | undefined do trigger the rule.