@@ -290,6 +290,7 @@ parseJSON_generic j = generic
290290 decodeArgs c0 = go (numConstrArgs (resType generic) c0) c0
291291 (constrFields c0)
292292 where
293+ go 0 c _ Null = construct c []
293294 go 1 c [] jd = construct c [jd] -- unary constructor
294295 go _ c [] (Array js) = construct c (V.toList js) -- no field names
295296 -- FIXME? We could allow reading an array into a constructor