diff --git a/src/cmd_context/cmd_context.cpp b/src/cmd_context/cmd_context.cpp
index ac0287312..b5c99f5ce 100644
--- a/src/cmd_context/cmd_context.cpp
+++ b/src/cmd_context/cmd_context.cpp
@@ -877,10 +877,11 @@ void cmd_context::insert(symbol const & s, func_decl * f) {
 }
 
 void cmd_context::insert(symbol const & s, psort_decl * p) {
+    pm().inc_ref(p);
     if (m_psort_decls.contains(s)) {
+        pm().dec_ref(p);
         throw cmd_exception("sort already defined ", s);
     }
-    pm().inc_ref(p);
     m_psort_decls.insert(s, p);
     if (!m_global_decls) {
         m_psort_decls_stack.push_back(s);