$ zig test test.zig
thread 10851 panic: reached unreachable code
Analyzing test.zig: test.zig:comptime_0
      %13 = optional_payload_unsafe_ptr(%9) node_offset:3:25 to :3:26
      %14 = field_type(@Zir.Inst.Ref.type_info_type, Struct) node_offset:4:32 to :4:34
      %15 = field_type(%14, layout) node_offset:5:23 to :5:28
      %16 = enum_literal("Auto") token_offset:5:24 to :5:28
      %17 = as_node(%15, %16) node_offset:5:23 to :5:28
      %18 = field_type(%14, fields) node_offset:6:23 to :6:24
      %19 = struct_init_anon([name=%13], [field_type=@Zir.Inst.Ref.u8_type], [default_value=@Zir.Inst.Ref.null_value], [is_comptime=@Zir.Inst.Ref.bool_false], [alignment=@Zir.Inst.Ref.one]) node_offset:6:26 to :6:28
      %20 = array_init_anon_ref({%19}) node_offset:6:24 to :6:26
      %21 = as_node(%18, %20) node_offset:6:23 to :6:24
      %22 = field_type(%14, decls) node_offset:13:22 to :13:26
      %23 = ref(@Zir.Inst.Ref.empty_struct) token_offset:13:23 to :13:24
      %24 = as_node(%22, %23) node_offset:13:22 to :13:26
      %25 = field_type(%14, is_tuple) node_offset:14:25 to :14:30
      %26 = as_node(%25, @Zir.Inst.Ref.bool_false) node_offset:14:25 to :14:30
      %27 = struct_init_anon([layout=%17], [fields=%21], [decls=%24], [is_tuple=%26]) node_offset:4:32 to :4:34
      %28 = as_node(%14, %27) node_offset:4:32 to :4:34
      %29 = struct_init_anon([Struct=%28]) node_offset:4:19 to :4:21
    > %30 = extended(reify(%29)) node_offset:4:13 to :4:18
      %31 = ensure_result_non_error(%30) node_offset:4:13 to :4:18
      %32 = break_inline(%12, @Zir.Inst.Ref.void_value)
    For full context, use the command
      zig ast-check -t test.zig

  in test.zig: test.zig:comptime_0
    > %11 = condbr_inline(%10, {%13..%32}, {%33}) node_offset:3:5 to :3:7
  in test.zig: test.zig:comptime_0
    > %12 = block_inline({%10, %11}) node_offset:3:5 to :3:7

zig/src/value.zig:2908:21: 0x8e2735 in elemValueAdvanced (zig)
            else => unreachable,
                    ^
zig/src/value.zig:2836:33: 0x73eac0 in elemValueBuffer (zig)
        return elemValueAdvanced(val, mod, index, null, buffer) catch unreachable;
                                ^
zig/src/value.zig:896:49: 0x73e906 in arrayToAllocatedBytes (zig)
            const elem_val = val.elemValueBuffer(mod, i, &elem_value_buf);
                                                ^
zig/src/value.zig:886:80: 0x73dce1 in toAllocatedBytes (zig)
                return arrayToAllocatedBytes(slice.ptr, slice.len.toUnsignedInt(target), allocator, mod);
                                                                               ^
zig/src/Sema.zig:18624:25: 0xe843c9 in reifyStruct (zig)
            Type.initTag(.const_slice_u8),
                        ^
zig/src/Sema.zig:18134:130: 0xaf484f in zirReify (zig)
            return try sema.reifyStruct(block, inst, src, layout, backing_int_val, fields_val, name_strategy, is_tuple_val.toBool());
                                                                                                                                 ^
zig/src/Sema.zig:1147:64: 0x8b418a in analyzeBodyInner (zig)
                    .reify                 => try sema.zirReify(             block, extended, inst),
                                                               ^
zig/src/Sema.zig:815:45: 0x743db5 in analyzeBodyBreak (zig)
    const break_inst = sema.analyzeBodyInner(block, body) catch |err| switch (err) {
                                            ^
zig/src/Sema.zig:1594:62: 0x8ba6b5 in analyzeBodyInner (zig)
                const break_data = (try sema.analyzeBodyBreak(block, inline_body)) orelse
                                                             ^
zig/src/Sema.zig:815:45: 0x743db5 in analyzeBodyBreak (zig)
    const break_inst = sema.analyzeBodyInner(block, body) catch |err| switch (err) {
                                            ^
zig/src/Sema.zig:1504:55: 0x8b8c69 in analyzeBodyInner (zig)
                    break :b try sema.analyzeBodyBreak(&child_block, inline_body);
                                                      ^
zig/src/Sema.zig:815:45: 0x743db5 in analyzeBodyBreak (zig)
    const break_inst = sema.analyzeBodyInner(block, body) catch |err| switch (err) {
                                            ^
zig/src/Module.zig:4634:50: 0x7400d6 in semaDecl (zig)
    const result_ref = (try sema.analyzeBodyBreak(&block_scope, body)).?.operand;
                                                 ^
zig/src/Module.zig:4255:38: 0x632e08 in ensureDeclAnalyzed (zig)
    const type_changed = mod.semaDecl(decl_index) catch |err| switch (err) {
                                     ^
zig/src/Compilation.zig:3217:38: 0x7230ce in processOneJob (zig)
            module.ensureDeclAnalyzed(decl_index) catch |err| switch (err) {
                                     ^
zig/src/Compilation.zig:3087:30: 0x6747ae in performAllTheWork (zig)
            try processOneJob(comp, work_item);
                             ^
zig/src/Compilation.zig:2396:31: 0x6706d0 in update (zig)
    try comp.performAllTheWork(main_progress_node);
                              ^
zig/src/main.zig:3354:20: 0x69cd96 in updateModule (zig)
    try comp.update();
                   ^
zig/src/main.zig:3021:17: 0x592cca in buildOutputType (zig)
    updateModule(gpa, comp, hook) catch |err| switch (err) {
                ^
zig/src/main.zig:236:31: 0x56d575 in mainArgs (zig)
        return buildOutputType(gpa, arena, args, .zig_test);
                              ^
zig/src/main.zig:174:20: 0x56c9d0 in main (zig)
    return mainArgs(gpa, arena, args);
                   ^
zig/lib/std/start.zig:614:37: 0x56ef51 in main (zig)
            const result = root.main() catch |err| {
                                    ^