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Feature suggestion: Report unused suppressions #22021
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Activity
This is not the intended use of
// @ts-ignore. we advice that this feature be used sparingly, and I do not think we want to invest in expanding its support.If this is a .d.ts file that you are testing, consider using https://github.com/Microsoft/dtslint, with
$ExpectTypeassertions.Reacted by AriaI see. Thanks for pointing to the correct solution!
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on Jul 25, 2018
When using advanced types such as conditional types, I usually write a bunch of type tests to check for which conditions the annotations are supposed to pass/fail. Example:
As you see, every first statement checks for a condition that's supposed to pass, while every second statement checks for a condition that's correctly supposed to fail.
I'd ideally annotate those second statements with
// @ts-ignore, except that if the expected type error doesn't happen, I wouldn't know about it. For example if the variablederivativeis of typeany, then the type annotations would obviously be wrong, but no errors would be shown.I propose a compiler flag like
warnUnusedSuppressions: booleanthat would produce a lint error if a line is annotated with// @ts-ignorebut doesn't contain type errors.Related issues: #19139, #21602