Custom iterator struct constructor does not work with for x in Iterator{} {

[spytheman]

V doctor:

V full version: V 0.4.5 872bcbc.55cafa9
OS: linux, Ubuntu 20.04.6 LTS
Processor: 4 cpus, 64bit, little endian, Intel(R) Core(TM) i3-3225 CPU @ 3.30GHz

getwd: /space/v/oo
vexe: /space/v/oo/v
vexe mtime: 2024-04-03 14:54:06

vroot: OK, value: /space/v/oo
VMODULES: OK, value: /home/delian/.vmodules
VTMP: OK, value: /tmp/v_1000

Git version: git version 2.42.0
Git vroot status: weekly.2024.14-8-g1dd1b650 (2 commit(s) behind V master)
.git/config present: true

CC version: cc (Ubuntu 10.5.0-1ubuntu1~20.04) 10.5.0
thirdparty/tcc status: thirdparty-linux-amd64 40e5cbb5

What did you do?
v -g -o vdbg cmd/v && vdbg /v/misc/2024_04_03__18/a.v

struct Iterator {
mut:
	counter int
}

fn (mut iter Iterator) next() ?int {
	if iter.counter > 0 {
		iter.counter--
		return iter.counter
	}
	return none
}

for x in Iterator{counter: 10} {
	dump(x)
}

What did you expect to see?

a compiled program, that when run, prints the numbers from 9 to 0 in descending order

What did you see instead?

/space/v/misc/2024_04_03__18/a.v:14:5: warning: unused variable: `x`
   12 | }
   13 | 
   14 | for x in Iterator{counter: 10} {
      |     ^
   15 |     dump(x)
   16 | }
/space/v/misc/2024_04_03__18/a.v:14:19: warning: label `counter` defined and not used
   12 | }
   13 | 
   14 | for x in Iterator{counter: 10} {
      |                   ~~~~~~~~~~~
   15 |     dump(x)
   16 | }
/space/v/misc/2024_04_03__18/a.v:14:10: error: undefined ident: `Iterator`
   12 | }
   13 | 
   14 | for x in Iterator{counter: 10} {
      |          ~~~~~~~~
   15 |     dump(x)
   16 | }
/space/v/misc/2024_04_03__18/a.v:15:7: error: undefined ident: `x`
   13 | 
   14 | for x in Iterator{counter: 10} {
   15 |     dump(x)
      |          ^
   16 | }
/space/v/misc/2024_04_03__18/a.v:15:7: error: dump expression can not be void
   13 | 
   14 | for x in Iterator{counter: 10} {
   15 |     dump(x)
      |          ^
   16 | }

Note that doing this instead, works:

...
set := Iterator{counter: 10}
for x in set {
...

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