No error on comptime expression loading runtime value

[kj4tmp]

Zig Version

0.14.0-dev.2540+f857bf72e

Steps to Reproduce and Observed Behavior

Create file test.zig with the following contents:

const std = @import("std");

test {
    var value = @as(u5, 0);
    const Foo = packed struct(u7) {
        val2: u7,
    };
    const foo: Foo = .{ .val2 = value };
    // if `comptime` is removed here, the segfault goes away
    std.debug.print("{}", .{comptime foo});
}

Observe segfault:

$ zig test test.zig 
Segmentation fault

Expected Behavior

Not sure, when I remove the comptime I get the following output:

test.zig:4:9: error: local variable is never mutated
    var value = @as(u5, 0);
        ^~~~~
test.zig:4:9: note: consider using 'const'

[Vexu]

That error is correct but if you suppress it with _ = &value there should be an unable to evaluate comptime expression error.

Stack trace

thread 374045 panic: reached unreachable code
/home/vexu/.config/Code - OSS/User/globalStorage/ziglang.vscode-zig/zig/linux-x86_64-0.14.0-dev.2547+77c63ac36/lib/std/debug.zig:405:14: 0xa41c14c in assert (zig)
    if (!ok) unreachable; // assertion failure
             ^
/home/vexu/Documents/zig/zig/src/Liveness.zig:174:15: 0xb66c7ce in analyze (zig)
        assert(data.live_set.count() == 0);
              ^
/home/vexu/Documents/zig/zig/src/Zcu/PerThread.zig:907:40: 0xb26a4e7 in linkerUpdateFunc (zig)
    var liveness = try Liveness.analyze(gpa, air, ip);
                                       ^
/home/vexu/Documents/zig/zig/src/link.zig:1548:32: 0xae68ac1 in doTask (zig)
            pt.linkerUpdateFunc(func.func, func.air) catch |err| switch (err) {
                               ^
/home/vexu/Documents/zig/zig/src/Compilation.zig:3900:20: 0xaab2ec8 in dispatchCodegenTask (zig)
        link.doTask(comp, tid, link_task);
                   ^
/home/vexu/Documents/zig/zig/src/Compilation.zig:3677:37: 0xa8433a7 in processOneJob (zig)
            comp.dispatchCodegenTask(tid, .{ .codegen_func = func });
                                    ^
/home/vexu/Documents/zig/zig/src/Compilation.zig:3634:30: 0xa65fe92 in performAllTheWorkInner (zig)
            try processOneJob(@intFromEnum(Zcu.PerThread.Id.main), comp, job, main_progress_node);
                             ^
/home/vexu/Documents/zig/zig/src/Compilation.zig:3494:36: 0xa4f4cec in performAllTheWork (zig)
    try comp.performAllTheWorkInner(main_progress_node);
                                   ^
/home/vexu/Documents/zig/zig/src/Compilation.zig:2251:31: 0xa4ed1d6 in update (zig)
    try comp.performAllTheWork(main_progress_node);
                              ^
/home/vexu/Documents/zig/zig/src/main.zig:4446:20: 0xa5285e7 in updateModule (zig)
    try comp.update(prog_node);
                   ^
/home/vexu/Documents/zig/zig/src/main.zig:3636:21: 0xa58f4d3 in buildOutputType (zig)
        updateModule(comp, color, root_prog_node) catch |err| switch (err) {
                    ^
/home/vexu/Documents/zig/zig/src/main.zig:273:31: 0xa41e4f1 in mainArgs (zig)
        return buildOutputType(gpa, arena, args, .zig_test);
                              ^
/home/vexu/Documents/zig/zig/src/main.zig:205:20: 0xa41b325 in main (zig)
    return mainArgs(gpa, arena, args);
                   ^
/home/vexu/.config/Code - OSS/User/globalStorage/ziglang.vscode-zig/zig/linux-x86_64-0.14.0-dev.2547+77c63ac36/lib/std/start.zig:656:37: 0xa41ae2e in main (zig)
            const result = root.main() catch |err| {
                                    ^