Compile time struct with union member access causes compiler error

[Ben0981]

Example

module c3test;

struct Test {
	char i;
	union {	
		char a;
	}
}

fn int main()
{
	Test $v = { .i = 5 };
	char $c = $v.a;
	return 0;
}

Problem

If Test.i is set but no member of the union is set trying to access $v.a causes a compiler error. If Test.i is not set or if the union is not anonymous the code runs without issue.

Maybe setting Test.i causes the rest of the struct to not be initialized whereas if no member is initialized the whole struct is properly initialized.

Compiler output

⚠️ The compiler encountered an unexpected error: "Violated assert: init->kind == CONST_INIT_STRUCT".

- Function: sema_expr_fold_to_struct_member(...)
- Source file: /home/ben/git/c3c/src/compiler/sema_expr.c:6340

and the version

C3 Compiler Version:       0.8.3 (Pre-release, Jul 17 2026 01:46:03)
Installed directory:       /usr/local/bin
Git Hash:                  303dd2230308420098f0f8d6601ba7d02338e2c8
Backends:                  LLVM
LLVM version:              22.1.8
LLVM default target:       x86_64-unknown-linux-gnu

[lerno]

This should be fixed now. Please try it out.