diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index b0df209d3dc..9d5189cfd0b 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -460,7 +460,7 @@ impl fmt::Display for clean::Type {
                     [] => primitive_link(f, clean::PrimitiveTuple, "()"),
                     [ref one] => {
                         try!(primitive_link(f, clean::PrimitiveTuple, "("));
-                        try!(write!(f, "{}", one));
+                        try!(write!(f, "{},", one));
                         primitive_link(f, clean::PrimitiveTuple, ")")
                     }
                     many => {