1 files changed, 6 insertions, 3 deletions
diff --git a/src/librustc_back/svh.rs b/src/librustc_back/svh.rs
index 116cff49153..98fa659ba55 100644
--- a/src/librustc_back/svh.rs
+++ b/src/librustc_back/svh.rs
@@ -340,14 +340,17 @@ mod svh_visitor {
                 // expensive; a direct content-based hash on token
                 // trees might be faster. Implementing this is far
                 // easier in short term.
-                let macro_defn_as_string =
-                    pprust::to_string(|pp_state| pp_state.print_mac(macro));
+                let macro_defn_as_string = pprust::to_string(|pp_state| {
+                    pp_state.print_mac(macro, token::Paren)
+                });
                 macro_defn_as_string.hash(self.st);
             } else {
                 // It is not possible to observe any kind of macro
                 // invocation at this stage except `macro_rules!`.
                 panic!("reached macro somehow: {}",
-                      pprust::to_string(|pp_state| pp_state.print_mac(macro)));
+                      pprust::to_string(|pp_state| {
+                          pp_state.print_mac(macro, token::Paren)
+                      }));
             }
 
             visit::walk_mac(self, macro);