diff --git a/examples/control_structs/if-test-1.cir b/examples/control_structs/if-test-1.cir
index 31030682e..41927bdf5 100644
--- a/examples/control_structs/if-test-1.cir
+++ b/examples/control_structs/if-test-1.cir
@@ -36,7 +36,6 @@ end
 echo
 
 echo "expect Error: testvar_d: no such variable."
-echo "expect Warning: NULL arithmetic expression"
 * in cp_istrue(): wl!=NULL then wl==NULL names==NULL v==NULL
 if $testvar_d
   echo "FAIL: you should not see this"
diff --git a/src/frontend/cpitf.c b/src/frontend/cpitf.c
index 669bdedbd..596ea97c7 100644
--- a/src/frontend/cpitf.c
+++ b/src/frontend/cpitf.c
@@ -306,6 +306,9 @@ cp_istrue(wordlist *wl)
     /* First do all the csh-type stuff here... */
     wl = wl_copy(wl);
     wl = cp_variablesubst(wl);
+    /* return FALSE if this did not expand to anything */
+    if (!wl)
+        return FALSE;
     wl = cp_bquote(wl);
     cp_striplist(wl);