do.call incompatibility

[brodieG]

> do.call(diffChr, list(1:2, 3:4))
< NULL       > NULL     
@@ 1,2 @@    @@ 1,2 @@  
< 1          > 3        
< 2          > 4        
Warning message:
In get_fun(found.call[[1L]], env = par.env) :
  Unable to find function `new("standardGeneric", .Data = function (target, current, ...) standardGeneric("diffChr"), generic = structure("diffChr", package = "diffobj"),     package = "diffobj", group = list(), valueClass = character(0),     signature = c("target", "current"), default = NULL, skeleton = (function (target,         current, ...)     stop("invalid call in method dispatch to 'diffChr' (no default method)",         domain = NA))(target, current, ...))` to match call with.