diff --git a/preprocessor b/preprocessor
index a3e63101f..e5121176a 160000
--- a/preprocessor
+++ b/preprocessor
@@ -1 +1 @@
-Subproject commit a3e63101f4fcacbe6a4f3ed98849215cecda1e7d
+Subproject commit e5121176a91a6105ab07b1bc7a0be18f3757f029
diff --git a/tests/example1_macro.mod b/tests/example1_macro.mod
index a9567d517..e56d391c2 100644
--- a/tests/example1_macro.mod
+++ b/tests/example1_macro.mod
@@ -157,10 +157,15 @@ stoch_simul;
 @#error "String comparison"
 @#endif
 
+@#define A = "La crise économique"
+@#if A[1,8,3,7,4,10,13,2,5,16,12,9,11,14,15,6,17:19] != "Le scénario comique"
+@#error "Problem with string indexing/comparison"
+@#endif
+
 @#define f(x) = x + "C"
 @#if "A" + f("B") != "ABC"
 @#error "Problem with String concatenation"
 @#endif
 
 @#echomacrovars(save)
-@#echomacrovars
+@#echomacrovars
\ No newline at end of file