Can't define in (if...) after (use-syntax (ice-9 syncase)) ?

[Cedric Cellier]

guile> (use-syntax (ice-9 syncase))
guile> (if #t (define foo "bar"))
ERROR: invalid context for definition of foo
ABORT: (misc-error)
guile> (version)
$1 = "1.8.7"

apparently syncase module is altering the if or define behavior somehow ?