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

I think there would be value in having a rule to avoid extra type-predicate checks when they're not necessary. This can help clean up type-predicates around a repo as types are changed, and also avoid unnecessary CPU cycles at runtime.

This rule would work similarly tono-unnecessary-type-assertion.

Fail Cases

consttest:"foo"="foo";constisFoo=(text:string):text is"foo"=>{returntext==="foo";}// Should error here: at compile time we know the else branch will never get hitif(isFoo(test)){console.log("FOO!");}else{console.log("BAR!");}

Pass Cases

consttest:string="bar";constisFoo=(text:string):text is"foo"=>{returntext==="foo";}// Shouldn't error here: at compile time we cannot know if the else branch will be hit, and so the predicate usage makes sense.if(isFoo(test)){console.log("FOO!");}else{console.log("BAR!");}

Additional Info

No response