diff --git a/corelib.wren b/corelib.wren
index c5ce252f..99cbcba7 100644
--- a/corelib.wren
+++ b/corelib.wren
@@ -19,7 +19,6 @@ class List {
     for (i in 0...this.count) {
       if (i > 0) result = result + ", "
       result = result + this[i].toString
-      i = i + 1
     }
     result = result + "]"
     return result
diff --git a/src/wren_core.c b/src/wren_core.c
index 174fcd51..0dd4d879 100644
--- a/src/wren_core.c
+++ b/src/wren_core.c
@@ -61,7 +61,6 @@ const char* coreLibSource =
 "    for (i in 0...this.count) {\n"
 "      if (i > 0) result = result + \", \"\n"
 "      result = result + this[i].toString\n"
-"      i = i + 1\n"
 "    }\n"
 "    result = result + \"]\"\n"
 "    return result\n"