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

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

My proposal is suitable for this project

• My proposal specifically checks TypeScript syntax, or it proposes a check that requires type information to be accurate.
• My proposal is not a "formatting rule"; meaning it does not just enforce how code is formatted (whitespace, brace placement, etc).
• I believe my proposal would be useful to the broader TypeScript community (meaning it is not a niche proposal).

Description

When a function parameter (or a class property) is marked as optional with?, it implicitly includesundefined in the type definition, so there is no need to explicitly add an| undefined to the type definition. I'd like to detect these cases and also autofix away the| undefined.

I don't think I see an existing rule to do this and it seems too complicated to do withno-restricted-syntax (though it wouldn't be able to autofix anyways).

Fail Cases

functionfoo(bar?:number|undefined){returnbar}

Pass Cases

functionfoo(bar?:number){returnbar}

Additional Info

No response