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=5.6.3&fileType=.tsx&code=CYUwxgNghgTiAEkoGdnwMoHsC2IDC0qAjPAN4CwAUPIpgHbIAuMArmI5jABRj1OvtOABVhRsALnhQ6ATwCUAbio1kOEAFkQjABaZgXXDr0iYYydPlLq8Vbk1HgAdQCWOgKIAPAA4RnYVwBKWiwwdAAqMl4gBlq6wCZiAPrmsnKS-M50AOZWNAD0efAAUixMUvAAZiAA7vDYnAiMIEzIAHTtyjZq9nEAgmBgIF6MmVl4UBAQAEZQYADWPBPTs3OSMQ4JElKp8AC8AHzblp22IEIwmFEwjDJrsBfVAGIsdOzO9Jsp8nuHAG6YzmAVgAvlQKi83vRaAxmGwODBNlw5GR4KDKODXiMoYY4ojkaRUWCIVi6HVYsZRNhEkiUWiMZDSfdME9ie86HjaVQqAV4O1WhgxAhtFAvFE6KN4NVXNp4DoEGIps4QHRGJVWVDQEhTCTxFzKJroHA1Zi2V1cM8TfQuPSSZ8jml4P9AVYbabXR9KTSCcCrNzCnz4FMWKq6JhVVKdLLtPLsIrlarfrBnFAphAEAbRCT4FxEzA8mnGHleDD4CAPGIfM00nqM0bc2aQAA1JMptNrMBLGbzO0WZEHR0AoFEy2kjuTLtzDnehTwHm9CCqeCh0swC4wNDOCqO2D5rRFviq5xoUogYDwTJMEBQM-RuA18CGhAFhvNmDJ1MgAAyWnbnZWm2-Rgvj7P5BxddVRz-btKUAr1UV9fUH1gBBizKU5X3fNM8APX9x3-SlsJhYCfgHZ1hwZRAoMnAiDzgn09R5AA5TAVzXDctzlGxhWAZlTyXQVzzQAADXMhN1SgqFrFDCDQLBcAIFBkAAJjITpUNhQRuHUgR4U2JTgNyBsej0dZcUpfT7RBKh620uFhHMqx6xxClTGwJSEKk40KNOC0GWtCC9IdJ0h0oet3XZByGP9dp4E4eAhILMT7y1aTFIwNQFNQABmVTrFszSeAPHT7NcrKDJObpyX0Zz4kpMrLKoNFn3y3S6qsZ8as2LKPKQo1wobXySX8kcuqCsDrNgLzbTaqLeRiuKhPUpKJMQlLEBk9L5JkgAWXKaBazhCphYqEUpbbyusU5jOqqrNnOhrKDRdToX4OzTtc3bdmzEDaSsZ7OrOvZvpI6dksfKbTR8iDhoZO6xrI0LJvCu6rCAA&eslintrc=N4KABGBEBOCuA2BTAzpAXGUEKQAIBcBPABxQGNoBLY-AWhXkoDt8B6Jge1uQAsBDACYcA7uiiJo0DtEjgwAXxDygA&tsconfig=N4KABGBEDGD2C2AHAlgGwKYCcDyiAuysAdgM6QBcYoEEkJemy0eAcgK6qoDCAFutAGsylBm3TgwAXxCSgA&tokens=false

Repro Code

The minimal reproduction is as follows:

declare class SomeClass {
  someMethod(methodParam: any); // ❌ `'methodParam' is already declared in the upper scope`
}
function methodParam() { }

If, however, function methodParam is instead a var, let or const declaration, the ESLint error is not triggered.

Quite a few more examples of this strange behavior are in the playground link.

ESLint Config

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

tsconfig

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

Expected Result

The error should always be reported or not reported no matter with what type of declaration the name of the parameter inside an ambient declaration clashes.

I personally can't tell whether it's technically shadowing or not. Perhaps having an option to treat clashes between real and ambient declarations' names as shadowing issues could be the solution.

Actual Result

The current behavior seems inconsistent to me.

Additional Info

No response