pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
let expr_kind = expr_type.kind();
pub fn is_slice_of_primitives(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
let expr_type = cx.typeck_results().expr_ty_adjusted(expr);
let expr_kind = expr_type.kind();