Suppress warnings in elixir 1.17

[k-asm]

Fix warnings in elixir 1.17 like:

• using map.field notation (without parentheses) to invoke function Test.User.__struct__() is deprecated, you must add parentheses instead: remote.function()
• single-quoted strings represent charlists. Use ~c"" if you indeed want a charlist or use "" instead

[bernardd]

Thanks @k-asm! Looks like some earlier versions of OTP might not have the correct typing specs to allow a binary rather than a charlist as the first argument of :gen_tcp.connect. Probably easier to just change it to a charlist.

With the __struct__ change, obviously it works but I'm just trying to understand it - do you know why __struct__() is suddenly a function? I was always under the impression that it was just a member in which case it shouldn't need the parentheses.

[k-asm]

Thanks for responding.

My understanding is that __struct__ is both as a member and automatically defined functions as __struct__/0 and __struct__/1 via defstruct.

I was diving into some older Elixir docs, and saw in the v1.10 docs (for example): "To define a struct, a developer must define both __struct__/0 and __struct__/1 functions. defstruct/1 is a convenience macro which defines such functions with some conveniences."

https://hexdocs.pm/elixir/1.10.4/Kernel.html#defstruct/1

[bernardd]

Ah, right you are. Doesn't quite explain why it won't let us just use the member rather than calling the function, but I guess it doesn't matter either way. Thanks again :)