[racket] TR: can I type-check an in-range at (Sequenceof Byte)?

This program

#lang typed/racket

(: seq (Sequenceof Byte))

(define seq (in-range 127))

...yields this error:

Type Checker: Expected (Sequenceof Byte), but got (Sequenceof Nonnegative-Fixnum) in: (define seq (in-range 127))

I'm wondering if there's a way to get (in-range 127) to type-check at the type (Sequenceof Byte). 

Naturally, I can make it typecheck by inserting a redundant "cond" at the point at which the values from the sequence are used.

John

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