diff --git a/src/solvers/smt2/smt2_conv.cpp b/src/solvers/smt2/smt2_conv.cpp
index 2402bb8ca92..fcb9256abaa 100644
--- a/src/solvers/smt2/smt2_conv.cpp
+++ b/src/solvers/smt2/smt2_conv.cpp
@@ -2483,7 +2483,8 @@ void smt2_convt::convert_expr(const exprt &expr)
   else
     INVARIANT_WITH_DIAGNOSTICS(
       false,
-      "smt2_convt::convert_expr should not be applied to unsupported type",
+      "smt2_convt::convert_expr should not be applied to unsupported "
+      "expression",
       expr.id_string());
 }