diff --git a/src/ast/ast_smt2_pp.cpp b/src/ast/ast_smt2_pp.cpp
index 63c7de1a9..c69cafc71 100644
--- a/src/ast/ast_smt2_pp.cpp
+++ b/src/ast/ast_smt2_pp.cpp
@@ -44,7 +44,7 @@ format * smt2_pp_environment::pp_fdecl_name(symbol const & s, unsigned & len) co
         return mk_string(m, str.c_str());
     }
     else if (!s.bare_str()) {
-        return mk_string(m,"null");
+        return mk_string(m, "null");
     }
     else {
         len = static_cast<unsigned>(strlen(s.bare_str()));