[racket] Cast in typed/racket/no-check

It seems like `cast` doesn't work at all in typed/racket/no-check:

#lang typed/racket/no-check

(cast 5 Number)

../../usr/lib/racket/collects/racket/contract/private/blame.rkt:89:0: 5:
broke its contract
 promised: #f
 produced: 5
 in: #f
 contract from: cast
 blaming: cast
 at: unsaved-editor1086360:3.0

The same error results if you do

(cast 5 String)

Is there an easy workaround for this?
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