X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=compiler%2Frustc_trait_selection%2Fsrc%2Ftraits%2Ferror_reporting%2Fsuggestions.rs;h=439854958270c4851385dd0d97d930a5edf559e4;hb=c1f8a3ffb2b9b155b400a675727ebd470938805c;hp=c52365ae3b7c7309cc90bd44db5de64e07573482;hpb=b7587f1867c73f3517d7071bb4989dd7e19540f1;p=rust.git

diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index c52365ae3b7..43985495827 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -1519,6 +1519,13 @@ fn suggest_change_mut(
                         .source_map()
                         .span_take_while(span, |c| c.is_whitespace() || *c == '&');
                     if points_at_arg && mutability.is_not() && refs_number > 0 {
+                        // If we have a call like foo(&mut buf), then don't suggest foo(&mut mut buf)
+                        if snippet
+                            .trim_start_matches(|c: char| c.is_whitespace() || c == '&')
+                            .starts_with("mut")
+                        {
+                            return;
+                        }
                         err.span_suggestion_verbose(
                             sp,
                             "consider changing this borrow's mutability",