diff --git a/src/expr.rs b/src/expr.rs
index ccc5017ea60..70695f30c4f 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -198,6 +198,10 @@ impl<'a> FmtVisitor<'a> {
         -> String {
         // opening paren
         let indent = offset + 1;
+        // In case of length 1, need a trailing comma
+        if items.len() == 1 {
+            return format!("({},)", self.rewrite_expr(&*items[0], width - 3, indent));
+        }
         // Only last line has width-1 as budget, other may take max_width
         let item_strs: Vec<_> =
             items.iter()
diff --git a/tests/idem/tuple.rs b/tests/idem/tuple.rs
index ab2d9e6272c..3655cab0663 100644
--- a/tests/idem/tuple.rs
+++ b/tests/idem/tuple.rs
@@ -7,4 +7,5 @@ fn foo() {
                                   aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,
                                   aaaaaaaaaaaaaaaaaaaaaaaaa,
                                   aaaa);
+    let a = (a,);
 }