diff --git a/src/eval.c b/src/eval.c
index 6950348..4796a25 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -5151,7 +5151,7 @@
      * Copy the string into allocated memory, handling backslashed
      * characters.
      */
-    name = alloc((unsigned)(p - *arg + extra));
+    name = alloc(p - *arg + extra);
     if (name == NULL)
 	return FAIL;
     rettv->v_type = VAR_STRING;
@@ -5285,7 +5285,7 @@
     /*
      * Copy the string into allocated memory, handling '' to ' reduction.
      */
-    str = alloc((unsigned)((p - *arg) - reduce));
+    str = alloc((p - *arg) - reduce);
     if (str == NULL)
 	return FAIL;
     rettv->v_type = VAR_STRING;
@@ -6782,8 +6782,8 @@
     temp_result = eval_to_string(expr_start + 1, &nextcmd, FALSE);
     if (temp_result != NULL && nextcmd == NULL)
     {
-	retval = alloc((unsigned)(STRLEN(temp_result) + (expr_start - in_start)
-						   + (in_end - expr_end) + 1));
+	retval = alloc(STRLEN(temp_result) + (expr_start - in_start)
+						   + (in_end - expr_end) + 1);
 	if (retval != NULL)
 	{
 	    STRCPY(retval, in_start);
@@ -8130,8 +8130,7 @@
 	if (!valid_varname(varname))
 	    return;
 
-	v = (dictitem_T *)alloc((unsigned)(sizeof(dictitem_T)
-							  + STRLEN(varname)));
+	v = (dictitem_T *)alloc(sizeof(dictitem_T) + STRLEN(varname));
 	if (v == NULL)
 	    return;
 	STRCPY(v->di_key, varname);
@@ -8993,7 +8992,7 @@
 	    }
 	    else
 	    {
-		winvarname = alloc((unsigned)STRLEN(varname) + 3);
+		winvarname = alloc(STRLEN(varname) + 3);
 		if (winvarname != NULL)
 		{
 		    STRCPY(winvarname, "w:");
@@ -9056,7 +9055,7 @@
     char_u	*scriptname;
 
     /* Get the script file name: replace '#' with '/', append ".vim". */
-    scriptname = alloc((unsigned)(STRLEN(name) + 14));
+    scriptname = alloc(STRLEN(name) + 14);
     if (scriptname == NULL)
 	return FALSE;
     STRCPY(scriptname, "autoload/");