Some slicing syntaxes fails inside generics

[edubart]

import arraymancer

proc test[T](t: Tensor[T]) =
  discard t[^1..0|-1] # fails
  discard t[0..1] # fails
  discard t[0..^1] # fails
  discard t[0..1|1] # works
  discard t[_] # works
  discard t[0] # works

zeros([2], int).test()

[mratsim]

It seems like for generics, macros are called before symbol resolution (but after identifier resolution).

This means that instead of giving me the proper symbol, Nim returns all the procs that are possible match:

Example for t[0..1]

------------------
Original tree
Arglist
  Infix
    OpenSymChoice
      Sym ".."
      Sym ".."
      Sym ".."
      Sym ".."
    Prefix
      OpenSymChoice
        Sym "^"
        Sym "^"
        Sym "^"
        Sym "^"
        Sym "^"
      IntLit 1
      Ident !"t"
    IntLit 1

Concretly that means that I have to redo my macros and have a specific test suite for generic procs.

[mratsim]

Something to try from PMunch:

https://github.com/zah/grip-lang/blob/master/compiler/patterns.nim#L69

proc inSymChoice(sc, x: PNode): bool =
  if sc.kind == nkClosedSymChoice:
    for i in 0.. <sc.len:
      if sc.sons[i].sym == x.sym: return true
  elif sc.kind == nkOpenSymChoice:
    # same name suffices for open sym choices!
    result = sc.sons[0].sym.name.id == x.sym.name.id

[mratsim]

Nim standard library is also struggling with macro/templates + Generics: nim-lang/Nim#7632 (strformat) and nim-lang/Nim#5053 ({.this: self.} pragma)