MachMessageServer::Interface implementations: minor cleanups

util/mach/exc_server_variants.cc

Index: util/mach/exc_server_variants.cc
diff --git a/util/mach/exc_server_variants.cc b/util/mach/exc_server_variants.cc
index 99875a849c50bb86f81606db92d181e4d8d84249..c0526d4e452ae2a3f0eec3e4ee5da65cff896f91 100644
--- a/util/mach/exc_server_variants.cc
+++ b/util/mach/exc_server_variants.cc
@@ -476,10 +476,12 @@ bool ExcServer<Traits>::MachMessageServerFunction(
           sizeof(out_reply->new_state[0]) * out_reply->new_stateCnt;
       return true;
     }
-  }
 
-  SetMIGReplyError(out_header, MIG_BAD_ID);
-  return false;
+    default: {
+      SetMIGReplyError(out_header, MIG_BAD_ID);
+      return false;
+    }
+  }
 }
 
 //! \brief A server interface for the `exc` or `mach_exc` Mach subsystems,