checker: fix multi return var passing to fn arg

[felipensp]

Fix #24870

[huly-for-github]

Connected to Huly®: V_0.6-24879

[spytheman]

Excellent work.

[spytheman]

I did not see the connection with the issue 🤔 , which seemed to report something related to the Context params in veb.

[spytheman]

No, it does not solve the issue (which was a bit hard to replicate):

#0 09:39:35 ^ master ~/v>git pull
remote: Enumerating objects: 9, done.
remote: Counting objects: 100% (6/6), done.
remote: Compressing objects: 100% (3/3), done.
remote: Total 9 (delta 3), reused 3 (delta 3), pack-reused 3 (from 1)
Receiving objects: 100% (9/9), 93.36 KiB | 985.00 KiB/s, done.
Resolving deltas: 100% (3/3), completed with 3 local objects.
From github.com:vlang/v
   84f68168ed..19ca0d0346  master     -> origin/master
Updating 84f68168ed..19ca0d0346
Fast-forward
#0 09:39:39 ^ master ~/v>./v self
V self compiling ...
V built successfully as executable "v".
#0 09:39:44 ^ master ~/v>v .
xxx.v:7:7: error: assignment mismatch: 1 variable but `a()` returns 2 values
    5 | }
    6 | fn main() {
    7 |     rets := a()
      |          ~~
    8 |     b(1, rets)
    9 | }
xxx.v:8:2: error: expected 2 arguments, but got 3
    6 | fn main() {
    7 |     rets := a()
    8 |     b(1, rets)
      |     ~~~~~~~~~~
    9 | }
Details: have (int literal, (int, int))
         want (int, []int)
#1 09:39:47 ^ master ~/v>cd -
/home/delian/v/peony
#0 09:39:50 ^ (HEAD detached at 21d031d) ~/v/peony>v .
================== C compilation error (from tcc): ==============
cc: /tmp/v_1000/peony.01K4M0TTYK4FCD7CGW2AHF5EZC.tmp.c:50969: warning: assignment from incompatible pointer type
cc: /tmp/v_1000/peony.01K4M0TTYK4FCD7CGW2AHF5EZC.tmp.c:57988: error: cannot convert 'struct string' to 'struct main__RetrieveProductParams'
...
cc: /tmp/v_1000/peony.01K4M0TTYK4FCD7CGW2AHF5EZC.tmp.c:57988: error: cannot convert 'struct string' to 'struct main__RetrieveProductParams'
(note: the original output was 10 lines long; it was truncated to its first 2 lines + the last line)
=================================================================
(You can pass `-cg`, or `-show-c-output` as well, to print all the C error messages).
#1 09:39:55 ^ (HEAD detached at 21d031d) ~/v/peony>

[spytheman]

the PR does solve an unrelated problem though, so perhaps it was just for another issue, not #24870 .

[felipensp]

the PR does solve an unrelated problem though, so perhaps it was just for another issue, not #24870 .

Interesting, for me it was