Rollup merge of rust-lang#90742 - est31:add_assign, r=davidtwco

Use AddAssign impl

Author: matthiaskrgr

compiler/rustc_ast/src/util/comments.rs

@@ -169,7 +169,7 @@ pub fn gather_comments(sm: &SourceMap, path: FileName, src: String) -> Vec<Comme
                 if let Some(mut idx) = token_text.find('\n') {
                     code_to_the_left = false;
                     while let Some(next_newline) = &token_text[idx + 1..].find('\n') {
-                        idx = idx + 1 + next_newline;
+                        idx += 1 + next_newline;
                         comments.push(Comment {
                             style: CommentStyle::BlankLine,
                             lines: vec![],

compiler/rustc_middle/src/util/common.rs

@@ -34,7 +34,7 @@ where
     let rv = f();
     let duration = start.elapsed();
     let mut accu = accu.lock();
-    *accu = *accu + duration;
+    *accu += duration;
     rv
 }