From 9189f6034a61351f4b1e17937a49030358d63503 Mon Sep 17 00:00:00 2001
From: Liu Dingming <liudingming@bytedance.com>
Date: Mon, 28 Feb 2022 21:18:31 +0800
Subject: [PATCH] iter_with_drain dogfood

---
 clippy_lints/src/suspicious_operation_groupings.rs        | 8 ++++----
 .../src/utils/internal_lints/metadata_collector.rs        | 6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/clippy_lints/src/suspicious_operation_groupings.rs b/clippy_lints/src/suspicious_operation_groupings.rs
index c3d984fb5ae1..940a8428f779 100644
--- a/clippy_lints/src/suspicious_operation_groupings.rs
+++ b/clippy_lints/src/suspicious_operation_groupings.rs
@@ -399,9 +399,9 @@ fn if_statment_binops(kind: &ExprKind) -> Option<Vec<BinaryOp<'_>>> {
 
 fn append_opt_vecs<A>(target_opt: Option<Vec<A>>, source_opt: Option<Vec<A>>) -> Option<Vec<A>> {
     match (target_opt, source_opt) {
-        (Some(mut target), Some(mut source)) => {
+        (Some(mut target), Some(source)) => {
             target.reserve(source.len());
-            for op in source.drain(..) {
+            for op in source {
                 target.push(op);
             }
             Some(target)
@@ -436,9 +436,9 @@ fn chained_binops_helper<'expr>(left_outer: &'expr Expr, right_outer: &'expr Exp
             chained_binops_helper(left_left, left_right),
             chained_binops_helper(right_left, right_right),
         ) {
-            (Some(mut left_ops), Some(mut right_ops)) => {
+            (Some(mut left_ops), Some(right_ops)) => {
                 left_ops.reserve(right_ops.len());
-                for op in right_ops.drain(..) {
+                for op in right_ops {
                     left_ops.push(op);
                 }
                 Some(left_ops)
diff --git a/clippy_lints/src/utils/internal_lints/metadata_collector.rs b/clippy_lints/src/utils/internal_lints/metadata_collector.rs
index 56633490eaa1..a617422bbeb0 100644
--- a/clippy_lints/src/utils/internal_lints/metadata_collector.rs
+++ b/clippy_lints/src/utils/internal_lints/metadata_collector.rs
@@ -473,7 +473,7 @@ impl<'hir> LateLintPass<'hir> for MetadataCollector {
     /// ```
     fn check_expr(&mut self, cx: &LateContext<'hir>, expr: &'hir hir::Expr<'_>) {
         if let Some(args) = match_lint_emission(cx, expr) {
-            let mut emission_info = extract_emission_info(cx, args);
+            let emission_info = extract_emission_info(cx, args);
             if emission_info.is_empty() {
                 // See:
                 // - src/misc.rs:734:9
@@ -483,7 +483,7 @@ impl<'hir> LateLintPass<'hir> for MetadataCollector {
                 return;
             }
 
-            for (lint_name, applicability, is_multi_part) in emission_info.drain(..) {
+            for (lint_name, applicability, is_multi_part) in emission_info {
                 let app_info = self.applicability_info.entry(lint_name).or_default();
                 app_info.applicability = applicability;
                 app_info.is_multi_part_suggestion = is_multi_part;
@@ -693,7 +693,7 @@ fn extract_emission_info<'hir>(
     }
 
     lints
-        .drain(..)
+        .into_iter()
         .map(|lint_name| (lint_name, applicability, multi_part))
         .collect()
 }