generic types, any -> opaque

std/os.zr

@@ -117,19 +117,19 @@ func os.is_a_directory[path: str] : bool
 
     return (mem.read32(st + 24) & S_IFMT) == S_IFDIR
 
-func os.list_directory[path: str] : Array, bool
+func os.list_directory[path: str] : Array<str>, bool
     fd := _builtin_syscall(SYS_openat, AT_FDCWD, path, O_RDONLY, 0)
     if fd < 0
-        return 0 as Array, false
+        return 0 as Array<str>, false
 
-    files := []
+    files := [] as Array<str>
     buf := _stackalloc(1024)
     while true
         n := _builtin_syscall(SYS_getdents64, fd, buf, 1024)
         if n < 0
             files->free_with_items()
             _builtin_syscall(SYS_close, fd)
-            return 0 as Array, false
+            return 0 as Array<str>, false
         else if n == 0
             break