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=5.9.3&fileType=.tsx&code=CYUwxgNghgTiAEYD2A7AzgF3lAXPA3vAEZ4AUAlPALwB88KArgLZEgwDciejLbnAvvAA%2B9BhAjsAUJKjUqVUeOEioAOiIV4AQnnZVYKUA&eslintrc=N4KABGBEBOCuA2BTAzpAXGUEKQAIBcBPABxQGNoBLY-AWhXkoDt8B6Y6RAM0WloHsalfkwCG8WmQAWo5uigB3UdCaRwYAL4gNQA&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkJemy0eAcgK6qoDCAFutAGsylBm3TgwAXxCSgA&tokens=false

Repro Code

declareconsta:{b:()=>number;c:number;}|null;a===null||a.b()!==a.c;

ESLint Config

{"rules":{"@typescript-eslint/prefer-optional-chain":"warn"}}

tsconfig

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

Expected Result

No warning.

Actual Result

An incorrect warning is emitted: "Prefer using an optional chain expression instead, as it's more concise and easier to read".

It suggests an autofix toa.b() !== a?.c which is not the same expression and creates a type error.

Additional Info

Seems to be a similar issue to#11700.