Repro

{"rules": {"@typescript-eslint/no-unnecessary-condition": ["error"]    }}

functiontest(testVal?:boolean){if(testVal??true){console.log('test');}}

Expected Result

No ESLint errors reported (condition inside the function is falsy only when we explicitly passtestVal = false).

Actual Result

2:20 error Unnecessary conditional, value is always truthy @typescript-eslint/no-unnecessary-condition

Additional info

I've noticed this recently when reading about additional options introduced in#1983, namelyallowComparingNullableBooleansToFalse. With that option set tofalse, code like this:

functiontest(testVal?:boolean){if(testVal!==false){console.log('test');}}

... turns into this with an autofix:

functiontest(testVal?:boolean){if((testVal??true)){console.log('test');}}

This is a valid transformation, since there should be only one situation whenconsole.log() is run - when thetestVal argument was explicitly set tofalse. Therefore,no-unnecessary-condition incorrectly reports that nullish coalescing is not needed here.

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