diff --git a/include/parrot/list.h b/include/parrot/list.h
index 01121fd06b..9e28835e59 100644
--- a/include/parrot/list.h
+++ b/include/parrot/list.h
@@ -105,13 +105,15 @@ void Parrot_list_append(SHIM_INTERP,
         FUNC_MODIFIES(*item);
 
 PARROT_EXPORT
-INTVAL Parrot_list_check(SHIM_INTERP, ARGIN(Linked_List *list))
+PARROT_CONST_FUNCTION
+INTVAL Parrot_list_check(SHIM_INTERP, ARGIN(const Linked_List *list))
         __attribute__nonnull__(2);
 
 PARROT_EXPORT
+PARROT_PURE_FUNCTION
 INTVAL Parrot_list_contains(SHIM_INTERP,
-    ARGIN(Linked_List *list),
-    ARGIN(List_Item_Header *item))
+    ARGIN(const Linked_List *list),
+    ARGIN(const List_Item_Header *item))
         __attribute__nonnull__(2)
         __attribute__nonnull__(3);
 
@@ -126,8 +128,7 @@ struct Linked_List* Parrot_list_new(SHIM_INTERP);
 
 PARROT_EXPORT
 PARROT_CAN_RETURN_NULL
-List_Item_Header* Parrot_list_pop(PARROT_INTERP, ARGIN(Linked_List *list))
-        __attribute__nonnull__(1)
+List_Item_Header* Parrot_list_pop(SHIM_INTERP, ARGIN(Linked_List *list))
         __attribute__nonnull__(2);
 
 PARROT_EXPORT
@@ -152,8 +153,7 @@ List_Item_Header* Parrot_list_remove(SHIM_INTERP,
        PARROT_ASSERT_ARG(list))
 #define ASSERT_ARGS_Parrot_list_new __attribute__unused__ int _ASSERT_ARGS_CHECK = (0)
 #define ASSERT_ARGS_Parrot_list_pop __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
-       PARROT_ASSERT_ARG(interp) \
-    , PARROT_ASSERT_ARG(list))
+       PARROT_ASSERT_ARG(list))
 #define ASSERT_ARGS_Parrot_list_remove __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
        PARROT_ASSERT_ARG(list) \
     , PARROT_ASSERT_ARG(item))
diff --git a/src/list.c b/src/list.c
index 52b67c9941..35fc9f7b30 100644
--- a/src/list.c
+++ b/src/list.c
@@ -43,7 +43,7 @@ Parrot_list_new(SHIM_INTERP)
 {
     ASSERT_ARGS(Parrot_list_new)
 
-    Linked_List *res = (Linked_List*)mem_sys_allocate_zeroed(sizeof (Linked_List));
+    Linked_List * const res = (Linked_List*)mem_sys_allocate_zeroed(sizeof (Linked_List));
     return res;
 }
 
@@ -119,8 +119,8 @@ Parrot_list_remove(SHIM_INTERP, ARGMOD(Linked_List *list), ARGMOD(List_Item_Head
 {
     ASSERT_ARGS(Parrot_list_remove)
 
-    List_Item_Header *next = item->next;
-    List_Item_Header *prev = item->prev;
+    List_Item_Header * const next = item->next;
+    List_Item_Header * const prev = item->prev;
 
     PARROT_ASSERT(list == item->owner);
 
@@ -153,11 +153,11 @@ Pop an item off the list - i.e. get the first item in the list and remove it.
 PARROT_EXPORT
 PARROT_CAN_RETURN_NULL
 List_Item_Header*
-Parrot_list_pop(PARROT_INTERP, ARGIN(Linked_List *list))
+Parrot_list_pop(SHIM_INTERP, ARGIN(Linked_List *list))
 {
     ASSERT_ARGS(Parrot_list_pop)
 
-    List_Item_Header *ret = list->first;
+    List_Item_Header * const ret = list->first;
     if (ret)
         LIST_REMOVE(list, ret);
     return ret;
@@ -165,7 +165,7 @@ Parrot_list_pop(PARROT_INTERP, ARGIN(Linked_List *list))
 
 /*
 
-=item C<INTVAL Parrot_list_check(PARROT_INTERP, Linked_List *list)>
+=item C<INTVAL Parrot_list_check(PARROT_INTERP, const Linked_List *list)>
 
 Check the validity of the list
 
@@ -174,12 +174,13 @@ Check the validity of the list
 */
 
 PARROT_EXPORT
+PARROT_CONST_FUNCTION
 INTVAL
-Parrot_list_check(SHIM_INTERP, ARGIN(Linked_List *list))
+Parrot_list_check(SHIM_INTERP, ARGIN(const Linked_List *list))
 {
     ASSERT_ARGS(Parrot_list_check)
 
-    List_Item_Header *tmp = list->first;
+    const List_Item_Header *tmp = list->first;
     size_t counter = 0;
 
     while (tmp) {
@@ -195,8 +196,8 @@ Parrot_list_check(SHIM_INTERP, ARGIN(Linked_List *list))
 
 /*
 
-=item C<INTVAL Parrot_list_contains(PARROT_INTERP, Linked_List *list,
-List_Item_Header *item)>
+=item C<INTVAL Parrot_list_contains(PARROT_INTERP, const Linked_List *list,
+const List_Item_Header *item)>
 
 Returns True if the is in the list
 
@@ -205,12 +206,13 @@ Returns True if the is in the list
 */
 
 PARROT_EXPORT
+PARROT_PURE_FUNCTION
 INTVAL
-Parrot_list_contains(SHIM_INTERP, ARGIN(Linked_List *list), ARGIN(List_Item_Header *item))
+Parrot_list_contains(SHIM_INTERP, ARGIN(const Linked_List *list), ARGIN(const List_Item_Header *item))
 {
     ASSERT_ARGS(Parrot_list_contains)
 
-    List_Item_Header *tmp = list->first;
+    const List_Item_Header *tmp = list->first;
 
 #ifndef NDEBUG
     if (item->owner != list)