I think you pasted the wrong code for charlie.nim. But anyway, it's a limitation of the method call syntax. See [https://nim-lang.github.io/Nim/manual.html#templates-limitations-of-the-method-call-syntax](https://nim-lang.github.io/Nim/manual.html#templates-limitations-of-the-method-call-syntax)
[Dump is a macro](https://github.com/nim-lang/Nim/blob/c59fa80367b25c83c0e35714a4e15862b704764e/lib/pure/sugar.nim#L184)
