Wrapping a closure iterator leads to execution of an external program failed

[bluenote10]

The following code fails to compile. It was a bit difficult to isolate the problem: Strangely, the problem disappears by removing either the when condition or one of the loops:

when true: # removing 'when' indentation => compiles

  iterator iter(): int {.closure.} =
    yield 0
    yield 1

  iterator wrappedIterator(it: iterator (): int): int {.closure.} =
    for x in it():
      yield x

  # Removing this loop => compiles, but
  # the behavior of the second loop is strange:
  # It is an infinite loop, always returning zero
  for x in iter():
    echo x

  # Removing this loop => compiles, and above
  # loop works fine.
  for x in iter.wrappedIterator:
    echo x

The compilation error is:

/home/fabian/github/NimExperiments/nimcache/repeatedIteratorUse.c: In function ‘repeatedIteratorUseInit’:
/home/fabian/github/NimExperiments/nimcache/repeatedIteratorUse.c:267:42: error: ‘HEX3Aenv_90222’ undeclared (first use in this function)
    LOC8.ClPrc = iter_90003; LOC8.ClEnv = HEX3Aenv_90222;
                                      ^
/home/fabian/github/NimExperiments/nimcache/repeatedIteratorUse.c:267:42: note: each undeclared identifier is reported only once for each function it appears in

I also do not understand why iter.wrappedIterator causes an infinite loop in the first place. Is this behavior expected? From my newbie point of view, I was expecting just to get the exact same iteration as in the first loop.

(Nim 0.10.3 -- using 28ecf72)

[bluenote10]

For sake of completeness: There is now a separate issue #2563 addressing the cause of the infinite loop I observed. Thus, this issue is only about the compilation error.

[dom96]

Compiles as of devel.

[dom96]

The behaviour of the compiled program is still an infinite loop. I assume #2563 talks about that issue though.