Allow for implicit int conversion to larger type

example/src/main.nub

@@ -1,37 +1,13 @@
 // c
 extern func puts(text: cstring)
 
-interface Printable
-{
-    func print()
-    func test()
-}
-
-struct Human : Printable
-{
-    name: cstring
-    age: u32
-
-    func print()
-    {
-        puts(this.name)
-    }
-
-    func test()
-    {
-        puts("test")
-    }
-}
-
 func main(args: []cstring): i64
 {
-    let x = struct Human {
-        name = "Oliver"
-        age = 23
-    }
-
-    x.print()
-    x.test()
-
+    let x: i32 = 23
+    test(x)
     return 0
 }
+
+func test(test: u8)
+{
+}