Use a multipart suggestion for the parentheses

Author: FabianWolff

compiler/rustc_lint/src/context.rs

@@ -751,9 +751,12 @@ pub trait LintContext: Sized {
                     }
                 }
                 BuiltinLintDiagnostics::BreakWithLabelAndLoop(span) => {
-                    if let Ok(code) = sess.source_map().span_to_snippet(span) {
-                        db.span_suggestion(span, "wrap this expression in parentheses", format!("({})", &code), Applicability::MachineApplicable);
-                    }
+                    db.multipart_suggestion(
+                        "wrap this expression in parentheses",
+                        vec![(span.shrink_to_lo(), "(".to_string()),
+                             (span.shrink_to_hi(), ")".to_string())],
+                        Applicability::MachineApplicable
+                    );
                 }
             }
             // Rewrap `db`, and pass control to the user.

src/test/ui/parser/lifetime_starts_expressions.stderr

@@ -35,11 +35,13 @@ warning: this labeled break expression is easy to confuse with an unlabeled brea
 LL | /         break 'label
 LL | |
 LL | |             loop { break 42; };
-   | |_____________-----------------^
-   |               |
-   |               help: wrap this expression in parentheses: `(loop { break 42; })`
+   | |______________________________^
    |
    = note: `#[warn(break_with_label_and_loop)]` on by default
+help: wrap this expression in parentheses
+   |
+LL |             (loop { break 42; });
+   |             ^                  ^
 
 error: aborting due to 2 previous errors; 1 warning emitted