Type error mentioned on Discord

type-error.pact

; Simplified example of a token implementation.
; When I run `(typecheck "my-token")` I get the error:
; > Typecheck my-token: Unable to resolve all types

(module my-token GOVERNANCE

  (defschema accounts-schema
    balance:integer
    guard:guard
  )

  (deftable accounts-table:{accounts-schema})

  (defcap GOVERNANCE ()
    true
  )

  (defcap NULL_GUARD ()
    "Used as a placeholder when calling with-default-read."
    false
  )

  (defun get-balance:integer (accountId:string)
    (with-default-read accounts-table accountId
      { "balance" : 0, "guard" : NULL_GUARD }
      { "balance" := balance }
      balance
    )
  )
)

(create-table accounts-table)