-var42 = ((val* (*)(val*, long))(var_str->class->vft[COLOR_abstract_collection__SequenceRead___91d_93d]))(var_str, var_i) /* [] on <var_str:String>*/;
-var44 = ((struct instance_kernel__Char*)var42)->value; /* autounbox from nullable Object to Char */;
-var43 = string__Char__to_s(var44);
-var45 = ((val* (*)(val*, val*))(var38->class->vft[COLOR_string__String___43d]))(var38, var43) /* + on <var38:String>*/;
-var_short_opt = var45;
-var46 = self->attrs[COLOR_opts__OptionContext___optmap].val; /* _optmap on <self:OptionContext> */
-if (var46 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _optmap", "lib/opts.nit", 277);
-exit(1);
-}
-var47 = ((short int (*)(val*, val*))(var46->class->vft[COLOR_abstract_collection__MapRead__has_key]))(var46, var_short_opt) /* has_key on <var46:Map[String, Option]>*/;
-if (var47){
-var48 = self->attrs[COLOR_opts__OptionContext___optmap].val; /* _optmap on <self:OptionContext> */
-if (var48 == NULL) {
-fprintf(stderr, "Runtime error: %s (%s:%d)\n", "Uninitialized attribute _optmap", "lib/opts.nit", 278);
-exit(1);
-}
-var49 = ((val* (*)(val*, val*))(var48->class->vft[COLOR_abstract_collection__MapRead___91d_93d]))(var48, var_short_opt) /* [] on <var48:Map[String, Option]>*/;
-var_option = var49;
+var42 = ((val* (*)(val*))(var_str->class->vft[COLOR_string__AbstractString__chars]))(var_str) /* chars on <var_str:String>*/;
+var43 = ((val* (*)(val*, long))(var42->class->vft[COLOR_abstract_collection__SequenceRead___91d_93d]))(var42, var_i) /* [] on <var42:StringCharView>*/;
+var45 = ((struct instance_kernel__Char*)var43)->value; /* autounbox from nullable Object to Char */;
+var44 = string__Char__to_s(var45);
+var46 = ((val* (*)(val*, val*))(var38->class->vft[COLOR_string__String___43d]))(var38, var44) /* + on <var38:String>*/;
+var_short_opt = var46;
+var47 = self->attrs[COLOR_opts__OptionContext___optmap].val; /* _optmap on <self:OptionContext> */
+if (var47 == NULL) {
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _optmap");
+fprintf(stderr, " (%s:%d)\n", "lib/opts.nit", 277);
+show_backtrace(1);
+}
+var48 = ((short int (*)(val*, val*))(var47->class->vft[COLOR_abstract_collection__MapRead__has_key]))(var47, var_short_opt) /* has_key on <var47:Map[String, Option]>*/;
+if (var48){
+var49 = self->attrs[COLOR_opts__OptionContext___optmap].val; /* _optmap on <self:OptionContext> */
+if (var49 == NULL) {
+fprintf(stderr, "Runtime error: %s", "Uninitialized attribute _optmap");
+fprintf(stderr, " (%s:%d)\n", "lib/opts.nit", 278);
+show_backtrace(1);
+}
+var50 = ((val* (*)(val*, val*))(var49->class->vft[COLOR_abstract_collection__MapRead___91d_93d]))(var49, var_short_opt) /* [] on <var49:Map[String, Option]>*/;
+var_option = var50;