bitstruct value cannot be used to index a const array in compile time. #2512
Description
import std::io;
bitstruct Some : char {
char v : 0 .. 4;
}
const int[8] SOME_MAP = some_macro();
macro some_macro () {
Some $s = { 8 };
int[8] $map;
$for var $i = 0; $i < 4; $i++:
$s = { .v = $s.v >> 1 };
$endfor;
$map[$s.v] = 1;
return $map;
}
fn void main() {
io::printfn("value is %s", SOME_MAP);
}
has following error:
➜ c3lang git:(main) ✗ c3c compile-run test.c3
12: $for var $i = 0; $i < 4; $i++:
13: $s = { .v = $s.v >> 1 };
14: $endfor;
15: $map[$s.v] = 1;
^^^^
(CodePlay/c3lang/test.c3:15:10) Error: Assigning to a compile time constant requires a constant index.
changes into $map[(uint)$s.v] = 1 works. however, I think the compile-time behavior should be the same with the runtime as the runtime it can work.
➜ c3lang git:(main) ✗ c3c -V
C3 Compiler Version: 0.7.7 (Pre-release, Oct 5 2025 17:51:29)
Git Hash: 1eb8c0ced147dc617de2a5f12235e95417f7e380
Backends: LLVM
LLVM version: 21.1.2
LLVM default target: arm64-apple-darwin24.4.0