compiler assertion with x86_64 native backend

[actondev]

Zig Version

0.14.0-dev.3299+31f353cd9

Steps to Reproduce and Observed Behavior

I've been trying lately to see if I can use the native backend in my application, but it keeps crashing.

        const exe = b.addExecutable(.{
            ...
            .use_llvm = optimize != .Debug,
            .use_lld = optimize != .Debug,
});

By compiling latest master, This is what I get.

error: thread 106850 panic: reached unreachable code
/home/actondev/dev/cloned/zig/lib/std/debug.zig:518:14: 0x19327fd in assert (zig)
    if (!ok) unreachable; // assertion failure
             ^
/home/actondev/dev/cloned/zig/src/Value.zig:135:11: 0x1b56d0e in fromInterned (zig)
    assert(i != .none);
          ^
/home/actondev/dev/cloned/zig/src/link/Dwarf.zig:3860:66: 0x2835e05 in updateLazyValue (zig)
                    try wip_nav.blockValue(src_loc, .fromInterned(opt.val));
                                                                 ^
/home/actondev/dev/cloned/zig/src/link/Dwarf.zig:2059:54: 0x23b28dd in updateLazy (zig)
            else => try wip_nav.dwarf.updateLazyValue(wip_nav.pt, src_loc, val, &wip_nav.pending_lazy),
                                                     ^
/home/actondev/dev/cloned/zig/src/link/Dwarf.zig:3124:27: 0x2ccf335 in updateComptimeNavInner (zig)
    try wip_nav.updateLazy(nav_src_loc);
                          ^
/home/actondev/dev/cloned/zig/src/link/Dwarf.zig:2683:34: 0x2797576 in updateComptimeNav (zig)
    return updateComptimeNavInner(dwarf, pt, nav_index) catch |err| switch (err) {
                                 ^
/home/actondev/dev/cloned/zig/src/link/Elf/ZigObject.zig:1601:64: 0x235110c in updateNav (zig)
    } else if (self.dwarf) |*dwarf| try dwarf.updateComptimeNav(pt, nav_index);
                                                               ^
/home/actondev/dev/cloned/zig/src/link/Elf.zig:2382:43: 0x1f47bee in updateNav (zig)
    return self.zigObjectPtr().?.updateNav(self, pt, nav);
                                          ^
/home/actondev/dev/cloned/zig/src/link.zig:706:81: 0x1cf7ae0 in updateNav (zig)
                return @as(*tag.Type(), @fieldParentPtr("base", base)).updateNav(pt, nav_index);
                                                                                ^
/home/actondev/dev/cloned/zig/src/Zcu/PerThread.zig:3128:21: 0x1b54bba in linkerUpdateNav (zig)
        lf.updateNav(pt, nav_index) catch |err| switch (err) {
                    ^
/home/actondev/dev/cloned/zig/src/link.zig:1566:35: 0x22d036d in doTask (zig)
                pt.linkerUpdateNav(nav_index) catch |err| switch (err) {
                                  ^
/home/actondev/dev/cloned/zig/src/link.zig:1384:34: 0x1ef7da2 in flushTaskQueue (zig)
        for (tasks) |task| doTask(comp, tid, task);
                                 ^
/home/actondev/dev/cloned/zig/lib/std/Thread/Pool.zig:182:50: 0x1ef7fb9 in runFn (zig)
            @call(.auto, func, .{id.?} ++ closure.arguments);
                                                 ^
/home/actondev/dev/cloned/zig/lib/std/Thread/Pool.zig:295:32: 0x1ea75a4 in worker (zig)
            run_node.data.runFn(&run_node.data, id);
                               ^
/home/actondev/dev/cloned/zig/lib/std/Thread.zig:488:13: 0x1c88dba in callFn__anon_171278 (zig)
            @call(.auto, f, args);
            ^
/home/actondev/dev/cloned/zig/lib/std/Thread.zig:757:30: 0x1b0b634 in entryFn (zig)
                return callFn(f, args_ptr.*);
                             ^
???:?:?: 0x73f6c56a3709 in ??? (libc.so.6)
Unwind information for `libc.so.6:0x73f6c56a3709` was not available, trace may be incomplete

I'm linking with c & c++ libraries FYI. I don't have my application open source anywhere. Let me know if I can help debugging this some way.

Expected Behavior

Compilation should work

[mlugg]

cc @jacobly0 -- normally I'd close this as an incomplete repro, but the logic on Dwarf.zig:3860 does look obviously wrong to me?

[actondev]

@mlugg managed to figure out a reproduction

// foo.zig
const Cb = fn (x: anytype) anyerror!void;

const Opts = struct {
    cb: ?*const Cb = null,
};
pub fn Foo(comptime opts: Opts) type {
    return struct {
        const opts_ = opts;
    };
}

test "foo" {
    const FooT = Foo(.{});
    _ = FooT;
}

zig test foo.zig -fno-llvm -fno-lld