Method process_varargs

calling a function with variadic arguments involves some transformations: function fun($x, ...$args) transformations will be: fun(1, 2, 3) -> fun(1, [2, 3]) fun(1, ...$arr) -> fun(1, $arr) fun(1, 2, 3, ...$arr1, ...$arr2) -> fun(1, array_merge([2, 3], $arr1, $arr2)) here we also deal with unpacking fixed-size arrays into positional arguments: fun(...[1]) -> fun(1) fun(...[1,2]) -> fun(1, [2]) fun(