diff --git a/core/src/gamecode/creport.c b/core/src/gamecode/creport.c
index 5f2ec83ba..fd49853f5 100644
--- a/core/src/gamecode/creport.c
+++ b/core/src/gamecode/creport.c
@@ -482,7 +482,8 @@ static void report_crtypes(FILE * F, const struct locale *lang)
       const struct nrmessage_type *nrt = nrt_find(lang, kmt->mtype);
       if (nrt) {
         unsigned int hash = kmt->mtype->key;
-        fprintf(F, "MESSAGETYPE %d\n", hash);
+        assert(hash > 0);
+        fprintf(F, "MESSAGETYPE %u\n", hash);
         fputc('\"', F);
         fputs(escape_string(nrt_string(nrt), NULL, 0), F);
         fputs("\";text\n", F);
@@ -548,7 +549,7 @@ static void render_messages(FILE * F, faction * f, message_list * msgs)
     nrbuffer[0] = '\0';
     if (nr_render(m->msg, f->locale, nrbuffer, sizeof(nrbuffer), f) > 0) {
       fprintf(F, "MESSAGE %u\n", messagehash(m->msg));
-      fprintf(F, "%d;type\n", hash);
+      fprintf(F, "%u;type\n", hash);
       fwritestr(F, nrbuffer);
       fputs(";rendered\n", F);
       printed = true;
diff --git a/core/src/kernel/spell.c b/core/src/kernel/spell.c
index 1a40e4067..6184d4b43 100644
--- a/core/src/kernel/spell.c
+++ b/core/src/kernel/spell.c
@@ -43,7 +43,7 @@ void free_spells(void) {
 
 void add_spell(struct quicklist **slistp, spell * sp)
 {
-  if (ql_set_insert(slistp, sp) != 0) {
+  if (!ql_set_insert(slistp, sp)) {
     log_error("add_spell: the list already contains the spell '%s'.\n", sp->sname);
   }
 }
diff --git a/core/src/util/message.c b/core/src/util/message.c
index 006ddc15e..7e9c1a9f0 100644
--- a/core/src/util/message.c
+++ b/core/src/util/message.c
@@ -42,9 +42,11 @@ message_type *mt_new(const char *name, const char *args[])
     log_error("Trying to create message_type with name=0x0\n");
     return NULL;
   }
-  if (args != NULL)
-    for (nparameters = 0; args[nparameters]; ++nparameters) ;
-
+  if (args != NULL) {
+    /* count the number of parameters */
+    while (args[nparameters]) ++nparameters;
+  }
+  mtype->key = 0;
   mtype->name = _strdup(name);
   mtype->nparameters = nparameters;
   if (nparameters > 0) {
@@ -188,7 +190,7 @@ const message_type *mt_register(message_type * type)
   unsigned int hash = hashstring(type->name) % MT_MAXHASH;
   quicklist **qlp = messagetypes + hash;
 
-  if (ql_set_insert(qlp, type) == 0) {
+  if (ql_set_insert(qlp, type)) {
     type->key = mt_id(type);
   }
   return type;