Cannot declare type-bound operators using type aliases

[alaviss]

Example

type
  FImpl = object
  
  F = FImpl
  
proc `=copy`*(a: var F, b: F) {.error.}

Current Output

test.nim(6, 1) Error: signature for '=copy' must be proc[T: object](x: var T; y: T)

Additional Information

$ nim -v
Nim Compiler Version 1.5.1 [Linux: amd64]
Compiled at 2021-01-05
Copyright (c) 2006-2020 by Andreas Rumpf

git hash: 2c2baa9fad1d144c42baf30ed004decdf8bb0483
active boot switches: -d:release -d:nimUseLinenoise

[cooldome]

Deliberatly so won't fix I believe. =copy operator is bound to a particular type, type alises can't be this type

[Araq]

Well we could accept this and attach the =copy to FImpl. But yeah, people tend to misuse type aliases and mistake them for independent types.

[cooldome]

distinct type needs to used in this case. I suggest to close as wont' fix.

[Araq]

The way I see the spec, the compiler should go ahead and attach the destructor to FImpl instead.