Symbols in `when false` section affect lookup about nim HOT 3 CLOSED

A clearer demo:

template valueOr*(def: untyped): int =
  when false:
    # Comment line below to make it work
    template error(): int {.gensym.} = discard
    discard
  else:
    template error(): int {.inject.} = 1
  def

let rErrV = valueOr error

It seems the symbol capture doesn't cover edge cases, when it comes to gensym

from nim.

In addition,

maybe there is another factor:

template valueOr*(def: untyped): int =
  template error(): int {.gensym.} = 1
  def

let rErrV = valueOr error

gensym is not considered when lookup

from nim.

Culprit is maybe this?

The gensym template is added to scope here and the injected template declaration finds it and reuses the symbol? Presumably to allow overloading the gensym'd symbol since adding gensym again defines a different symbol, even though omitting gensym implies inject for routines. Then again why does gensym again define a different symbol when we only get to use one at a time in the template?

We could move the gensym reuse logic inside the logic for when gensym is given, if this breaks code we could allow opting out of the symbol reuse on an explicit inject.

This is all letting alone the logic of actually using error inside the template after the when block, also I'm speculating about all this from my phone so I might be wrong.

from nim.