fix dogfood lints

Author: sebhernandezr

clippy_lints/src/unnecessary_split_off.rs

@@ -1,7 +1,7 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::sym;
 use rustc_errors::Applicability;
-use rustc_hir::*;
+use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::declare_lint_pass;
 
@@ -30,14 +30,15 @@ declare_lint_pass!(UnnecessarySplitOff => [UNNECESSARY_SPLIT_OFF]);
 impl<'tcx> LateLintPass<'tcx> for UnnecessarySplitOff {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
         if let ExprKind::MethodCall(path, value, args, span) = &expr.kind
+        // FIXME: sym::split_off does not exist, but this still triggers the lint to use it.
             && path.ident.name.as_str() == "split_off"
         {
             let ty = cx.typeck_results().expr_ty(value);
             if clippy_utils::ty::is_type_diagnostic_item(cx, ty, sym::Vec) {
                 let &[arg] = args else {
                     return;
                 };
-                if clippy_utils::is_integer_literal(&arg, 0) || clippy_utils::is_integer_const(cx, &arg, 0) {
+                if clippy_utils::is_integer_literal(arg, 0) || clippy_utils::is_integer_const(cx, arg, 0) {
                     span_lint_and_sugg(
                         cx,
                         UNNECESSARY_SPLIT_OFF,