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 have searched for related issues and found none that matched my issue.
• I have read 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

declare const a: { 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 to a.b() !== a?.c which is not the same expression and creates a type error.

Additional Info

Seems to be a similar issue to #11700.