From type/Test

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sub fails-like ( \test where Callable:D|Str:D, $ex-type, $reason?, *%matcher)

Same interface as throws-like, except checks that the code returns a Failures instead of throwing. If the code does throw or if the returned Failures has already been handled, that will be considered as a failed test.

fails-like { +"a" }, X::Str::Numeric,
    :message(/'Cannot convert string to number'/),
    'converting non-numeric string to number fails';