C error: json2.decoder2 array of sumtypes one empty struct #25263
Description
V version: V 0.4.11 847c15e, press to see full `v doctor` output
| V full version | V 0.4.11 e96355a.847c15e |
|---|---|
| OS | linux, Ubuntu 22.04.5 LTS |
| Processor | 4 cpus, 64bit, little endian, Intel(R) Core(TM) i3-4150 CPU @ 3.50GHz |
| Memory | 0.51GB/3.7GB |
| V executable | /home/jorge/v/v |
| V last modified time | 2025-09-08 18:40:30 |
| V home dir | OK, value: /home/jorge/v |
| VMODULES | OK, value: /home/jorge/.vmodules |
| VTMP | OK, value: /tmp/v_1000 |
| Current working dir | OK, value: /home/jorge/bugs/250908 |
| Git version | git version 2.34.1 |
| V git status | weekly.2025.16-741-g847c15e5-dirty |
| .git/config present | true |
| cc version | cc (Ubuntu 11.4.0-1ubuntu1~22.04.2) 11.4.0 |
| gcc version | gcc (Ubuntu 11.4.0-1ubuntu1~22.04.2) 11.4.0 |
| clang version | Ubuntu clang version 14.0.0-1ubuntu1.1 |
| tcc version | tcc version 0.9.28rc 2025-02-13 HEAD@f8bd136d (x86_64 Linux) |
| tcc git status | thirdparty-linux-amd64 696c1d84 |
| emcc version | emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 3.1.5 () |
| glibc version | ldd (Ubuntu GLIBC 2.35-0ubuntu3.10) 2.35 |
What did you do?
./v -g -o vdbg cmd/v && ./vdbg 250908-c.v && 250908-c
import x.json2.decoder2
struct Empty {
}
type Elem = int | Empty
fn main() {
text := '[ 0, { }, 2 ]'
e := decoder2.decode[[]Elem](text) or {
dump(err)
return
}
dump(e)
}What did you see?
================== C compilation error (from tcc): ==============
cc: /tmp/v_1000/250908-c.01K4NK3S5452FS91A6W19EREBC.tmp.c:10323: error: ';' expected (got "}")
=================================================================
(You can pass `-cg`, or `-show-c-output` as well, to print all the C error messages).
builder error:
==================
C error found. It should never happen, when compiling pure V code.
This is a V compiler bug, please report it using `v bug file.v`,
or goto https://github.com/vlang/v/issues/new/choose .
You can also use #help on Discord: https://discord.gg/vlang .
What did you expect to see?
A decoded array of sumtypes
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