Before You File a Proposal Please Confirm You Have Done The Following...

• I have searched for related issues and found none that match my proposal.
• I have searched the current rule list and found no rules that match my proposal.
• I have read the FAQ and my problem is not listed.

My proposal is suitable for this project

• I believe my proposal would be useful to the broader TypeScript community (meaning it is not a niche proposal).

Link to the rule's documentation

https://typescript-eslint.io/rules/no-unsafe-declaration-merging/

Description

For most application code, interface declaration merging is probably an accidental name conflict instead of the intended usage. I propose to either change the default behavior of no-unsafe-declaration-merging, or add an option disallowing interface-interface declaration merging.

Changing the default value might be a breaking change, so adding an option seems like a better way to move forward.

Fail

interface Foo {
  x: string;
}

interface Foo {
  y: number;
}

Pass

interface Foo {
  x: string;
  y: number;
}

Additional Info

No response