3 files changed, 13 insertions, 3 deletions
diff --git a/README b/README
index 4d5de85..c83be3a 100644
--- a/README
+++ b/README
@@ -14,3 +14,8 @@ For every line,
 - dot or other, take literally (as a desc)
 
 Always trim ending spaces
+
+# bugs
+
+the possibility that `malloc == NULL` is pretty much ignored, memory
+handling is probably lossy, and pointer chasing is inefficient
diff --git a/ll.c b/ll.c
index 910b869..3481b8b 100644
--- a/ll.c
+++ b/ll.c
@@ -1,9 +1,14 @@
 #include <stdlib.h>
+#include <assert.h>
 #include "ll.h"
 
-llnode* appendll(llnode* tail, char* str){
+llnode* appendll(llnode* tail, /*@nottemp@*/char* str){
     llnode* new = malloc(sizeof(llnode));
-    if (tail != NULL) tail->next = new;
+    assert(new != NULL);
+    if (tail != NULL) {
+        assert(tail->next == NULL);
+        tail->next = new;
+    }
     new->str = str;
     new->next = NULL;
     return new;
diff --git a/ll.h b/ll.h
index 9a80182..cea6010 100644
--- a/ll.h
+++ b/ll.h
@@ -7,6 +7,6 @@ typedef struct llnode {
     struct llnode* next;
 } llnode;
 
-llnode* appendll(llnode* tail, char* str);
+llnode* appendll(llnode* tail, /*@notnull@*/char* str);
 
 #endif