compiler segmentation fault when tagged unions in custom logging function

[texmex76]

Zig Version

0.13.0

Steps to Reproduce and Observed Behavior

const std = @import("std");
pub const std_options = .{
    .logFn = myLogFn,
};
const UnionEnum = union(enum) {};
pub fn myLogFn(
    comptime l: anytype,
    comptime s: anytype,
    comptime f: anytype,
    a: UnionEnum,
) void {
    _ = l;
    _ = s;
    _ = f;
    _ = a;
}
pub fn main() void {}

When trying to build the above code using zig build-exe, the compiler segfaults:

[1]    13323 segmentation fault  zig build-exe main.zig

Expected Behavior

Expected the compiler to give any output and exit gracefully.

I looked a bit around and 18518 looks similar, but that one was already resolved and the compiler does not crash anymore for the input given in that bug report.

[rohlem]

Still reproduces for me on newer version 0.14.0-dev.1579+f3445f8f6.
FYI, the issue is probably with your union type: Since it has no possible states, it is an uninstantiable type (aka noreturn-like), which aren't valid in arguments to called/instantiated functions. (See also #15909 for planned behavior.)
As you've stated though, the compiler crashing is a bug, it should instead result in a compile error pointing out the problem.
Update: As stated below, apparently there's a separate bug at play. After that it makes sense to re-test whether the compiler still crashes here or correctly reports the error.

[Vexu]

Duplicate of #21099