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

Validate that overriden method signatures match the base signature (i.e. no narrowing of types)

Fail Cases

classA{f(p:string|number){console.log('A',p);}}classBextendsA{f(p:string){console.log('B',p,p.charCodeAt(0));}}constarrayOfA:Array<A>=[newA(),newB()];for(constitemofarrayOfA){item.f(123);}

Pass Cases

classA{f(p:string|number){console.log('A',p);}}classBextendsA{f(p:string|number){<--Needstomatchbaseclassmethodsignatureconsole.log('B',p,p.charCodeAt(0));}}constarrayOfA:Array<A>=[newA(),newB()];for(constitemofarrayOfA){item.f(123);}

Additional Info

TS issue was closed as "working as intended" but this is very dangerous, since this breaks some type safety, meaning that this introduces a risk of runtime errors