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=5.7.2&fileType=.tsx&code=KYDwDg9gTgLgBASwHY2FAZgQwMbDgMQQBtUoAZBAZxgElUBbSmpMAVxgB4AVAPjgG8AUHEQNKALjgBBKFEwBPbj2FxKwTFGwALSdSjIA5oIC%2BgwaEiw46VkmwwEEJNeKkK1OsEYAheQGlgeUolAAoVflEvSgAaVXVNLThjSUISNHdaMWY2Tl5olQBrQIlpWQUOIvkIdDg8wQBKSRk5RV4BFWwnajgiCAB3NABhTDUAZXjtOABeOI1tADoYCDJ%2BoZHgEPqzEShgGFYoZwQxefRXNBCQ46966eUREUrKecoIeg2Qytupvmv6AG1KgBdAD8iwgoxg%2BiQBk24JWAygwzUcOQ2CIrAAJsBKCFeojkcBxnMtPV6vkRFtjEA&eslintrc=N4KABGBEBOCuA2BTAzpAXGUEKQAIBcBPABxQGNoBLY-AWhXkoDt8B6Jge1tiacTJTIAhtEK0yHJgBNK%2BSpPRRE0aB2iRwYAL4gtQA&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkJemy0eAcgK6qoDCAFutAGsylBm3TgwAXxCSgA&tokens=false

Repro Code

exportinterfaceFilterListItemsInput<T>{items:Array<T>search:string}exportfunctionfilterListItemsByKeys<T>({ items, search}:FilterListItemsInput<T>,keys:Array<keyofT>,):Array<T>{constlowerCaseSearch=search.toLowerCase()returnitems.filter((item)=>keys.some((key)=>item[key]?.toString().toLowerCase().includes(lowerCaseSearch)),)}

ESLint Config

module.exports={parser:"@typescript-eslint/parser",rules:{"@typescript-eslint/no-unnecessary-condition":"error",},};

tsconfig

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

Expected Result

I expect the code above not to error becauseitem[key]can be nullish, but the ESLint rule says it can't.

Actual Result

ESLint: Unnecessary optional chain on a non-nullish value.(@typescript-eslint/ no-unnecessary-condition)

Additional Info

I found#9754 which seems similar, though I don't think it's quite the same.