diff --git a/list.c b/list.c
index 7f5f7bf..640529b 100644
--- a/list.c
+++ b/list.c
@@ -344,6 +344,10 @@ list_reverse (struct list *list)
     }
 }
 
+static bool
+is_sorted (struct list_elem *a, struct list_elem *b,
+           list_less_func *less, void *aux) __attribute__((__unused__));
+
 /* Returns true only if the list elements A through B (exclusive)
    are in order according to LESS given auxiliary data AUX. */
 static bool
diff --git a/mdriver.c b/mdriver.c
index fbdeb1b..5c95ef6 100644
--- a/mdriver.c
+++ b/mdriver.c
@@ -674,13 +674,13 @@ static trace_t *read_trace(char *tracedir, char *filename, int verbose)
     }
     int rc;
     rc = fscanf(tracefile, "%d", &(trace->sugg_heapsize)); /* not used */
-    assert (rc == 1);
+    if (rc != 1) abort();
     rc = fscanf(tracefile, "%d", &(trace->num_ids));     
-    assert (rc == 1);
+    if (rc != 1) abort();
     rc = fscanf(tracefile, "%d", &(trace->num_ops));     
-    assert (rc == 1);
+    if (rc != 1) abort();
     rc = fscanf(tracefile, "%d", &(trace->weight));        /* not used */
-    assert (rc == 1);
+    if (rc != 1) abort();
     
     /* We'll store each request line in the trace in this array */
     if ((trace->ops =