Dependency loop caused by explicit mentioning of function pointer type

[copygirl]

Zig Version

0.11.0

Steps to Reproduce and Observed Behavior

With the following zig code:

const ecs_iter_next_action_t = ?*const fn (*ecs_iter_t) void;
const ecs_iter_t = struct { next: ecs_iter_next_action_t };

test {
    _ = ecs_iter_next_action_t;
}

pub fn main() void {
    var it = ecs_iter_t{ .next = &next_action };
    it.next.?(&it);
}

fn next_action(it: *ecs_iter_t) void {
    @import("std").debug.print("{any}\n", .{it});
}

Running zig run yields the expected output:

main.ecs_iter_t{ .next = fn(*main.ecs_iter_t) void@220780 }

However when running zig test (here with -freference-trace), I get a dependency loop error:

main.zig:1:1: error: dependency loop detected
const ecs_iter_next_action_t = ?*const fn (*ecs_iter_t) void;
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
referenced by:
    ecs_iter_t: main.zig:2:20
    ecs_iter_next_action_t: main.zig:1:45
    ecs_iter_t: main.zig:2:35

Expected Behavior

No dependency loop.

[copygirl]

If I change the main function to the following, the dependency loop error also occurs for zig run.

pub fn main() void {
    var next: ecs_iter_next_action_t = &next_action;
    var it = ecs_iter_t{ .next = next };
    it.next.?(&it);
}

However, only if the type is actually specified, change the second line to this and it's fine again:

var next = &next_action;

[copygirl]

I also have a larger codebase where I wrap some C code where this issue occurs. Sometimes. Seemingly randomly. Practically the same code compiled earlier and now that I made some seemingly unrelated changes, the dependency loop error is back.

[dvmason]

I just created #22543 which has some things in common.