.this pragma doesn't work with generics

[Swend5]

type
  A[T] = object
    x: T
{.this: self.}
proc testproc[T](self: A[T]) =
  echo x

type
  A = object
    x: int
{.this: self.}
proc testproc(self: A) =
  echo x

First example results in Error: undeclared identifier: 'x', second example compiles without issue.

[Swend5]

It works if the template is instantiated, maybe it has something to do with that.

type A[T] = object
  x: T
{.this: self.}
proc testproc[T](self: A[int]) =
  echo x

[branpk]

The issue is that x is looked up before testproc is instantiated, and the existence of x can depend on T. For example:

type A[T] = object
  when T is int:
    x: T

The compiler also looks up symbols when it generates an instantiation, so removing the pre-instantiation lookup doesn't appear to break anything, and it fixes this issue. But maybe it's there for a reason.

[Araq]

The pre-instantiation lookup is required to implement the proper "open vs closed symbol lookup" rules.

http://nim-lang.org/docs/manual.html#generics-symbol-lookup-in-generics

It's a tough issue, maybe we need to weaken the prepass if a 'this' parameter is used.

[Swend5]

Is there some temporary workaround you can think of?

[nc-x]

{.this.} is deprecated. Can be closed?