Add Clone trait bound to write_list

src/expr.rs

@@ -1707,7 +1707,7 @@ impl Rewrite for ast::Arm {
             ends_with_newline: false,
             config: context.config,
         };
-        let pats_str = try_opt!(write_list(items, &fmt));
+        let pats_str = try_opt!(write_list(&items, &fmt));
 
         let guard_shape = if pats_str.contains('\n') {
             shape.with_max_width(context.config)

src/items.rs

@@ -478,7 +478,7 @@ impl<'a> FmtVisitor<'a> {
             config: self.config,
         };
 
-        let list = try_opt!(write_list(items, &fmt));
+        let list = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
         result.push_str(&list);
         result.push('\n');
         Some(result)
@@ -2539,7 +2539,7 @@ fn rewrite_where_clause_rfc_style(
         ends_with_newline: true,
         config: context.config,
     };
-    let preds_str = try_opt!(write_list(items, &fmt));
+    let preds_str = try_opt!(write_list(&items.collect::<Vec<_>>(), &fmt));
 
     Some(format!(
         "{}where\n{}{}",

src/lists.rs

@@ -157,7 +157,7 @@ where
 // TODO: add unit tests
 pub fn write_list<I, T>(items: I, formatting: &ListFormatting) -> Option<String>
 where
-    I: IntoIterator<Item = T>,
+    I: IntoIterator<Item = T> + Clone,
     T: AsRef<ListItem>,
 {
     let tactic = formatting.tactic;