The typecheck error has no srcloc. Also the "in:" expression is the entire `test` submodule, not the specific piece of it. (In a longer example, the piece might even be ellided, after the "...".)

gistfile1.rkt

#lang typed/racket/base
(require racket/flonum)
(module+ test
  (require typed/rackunit)
  (define (from upto)
    (for/flvector ([i (in-range from upto)])
      0.0)))

; Type Checker: Error in macro expansion -- insufficient type information to typecheck. please add more type annotations
;   in: ((require typed/rackunit) (define (from upto) (for/flvector ((i (in-range from upto))) 0.0)))

;;; Notice two problems:
;;;
;;; 1. There is no srcloc in the error message.
;;;
;;; 2. The "in:" expression is the entire `test` submodule contents, not
;;;    the specific piece that didn't typecheck.
;;;
;;; It seems to be related to using `for/flvector`.