bug#20512: bogus warning with (format) and ~{ ~}

[levenson]

I encounter similar behavior, but for dynamic padding, but it one case
it doesn't even work. I am using guile 2.2.6 from guix distro

scheme@(guile-user)> (format #f "~:{~v_ ~a ~}" '((5 "hello")))

FORMAT: error with call: (format #f "~:{~v_ ~a ~}<===" ((5 hello)) ===>)
        missing argument(s)
In ice-9/format.scm:
  1590:19  2 (format #f "~:{~v_ ~a ~}" ((5 "hello")))
   197:20  1 (format:format-work "~:{~v_ ~a ~}" (((5 "hello"))))
In unknown file:
           0 (scm-error misc-error #f "~A" ("error in format") #f)
error in format

Added the bogus 0 which doesn't do anything

scheme@(guile-user)> (format #f "~:{~v_ ~a ~}" 0 '((5 "hello")))
;;; <stdin>:3:0: warning: "~:{~v_ ~a ~}": wrong number of `format' arguments: 
expected 1, got 2
$1 = "      hello "


-- 
Alexey