diff --git a/src/calc.cpp b/src/calc.cpp
index 2bc291c3a..c21ec82cf 100644
--- a/src/calc.cpp
+++ b/src/calc.cpp
@@ -58,7 +58,7 @@ int main (int argc, char** argv)
 
   try
   {
-    bool infix {true};
+    auto infix {true};
 
     // Add a source for constants.
     Eval e;