Using @TypeOf(x) as return type causes nothing to be emitted

[Validark]

Zig Version

0.14.0-dev.3237+ddff1fa4c

Steps to Reproduce and Observed Behavior

This code fails to emit IR, seemingly because of the @TypeOf(s) (Godbolt)

export fn foo(s: u64) @TypeOf(s) {
    return s;
}

Expected Behavior

It should be equivalent to:

export fn foo(s: u64) u64 {
    return s;
}

The last working version of Zig I have on my machine is v0.14.0-dev.2851+b074fb7dd. The first broken version I have is v0.14.0-dev.3028+cdc9d65b0

[Vexu]

LLVM backend stack trace

thread 553102 panic: attempt to use null value
/home/vexu/Documents/zig/zig/src/codegen/llvm.zig:1821:57: 0xa737ad0 in updateExports (zig)
        const global_index = self.nav_map.get(nav_index).?;
                                                        ^
/home/vexu/Documents/zig/zig/src/link/Elf.zig:2419:73: 0xa8fb822 in updateExports (zig)
    if (self.llvm_object) |llvm_object| return llvm_object.updateExports(pt, exported, export_indices);
                                                                        ^
/home/vexu/Documents/zig/zig/src/link.zig:865:85: 0xa7370ba in updateExports (zig)
                return @as(*tag.Type(), @fieldParentPtr("base", base)).updateExports(pt, exported, export_indices);
                                                                                    ^
/home/vexu/Documents/zig/zig/src/Zcu/PerThread.zig:2962:69: 0xa5a4dd4 in processExportsInner (zig)
        try zcu.handleUpdateExports(export_indices, lf.updateExports(pt, exported, export_indices));
                                                                    ^
/home/vexu/Documents/zig/zig/src/Zcu/PerThread.zig:2893:35: 0xa5a374d in processExports (zig)
        try pt.processExportsInner(&symbol_exports, exported, exports_list.items);
                                  ^
/home/vexu/Documents/zig/zig/src/Compilation.zig:2287:30: 0xa5af3c5 in update (zig)
        try pt.processExports();
                             ^
/home/vexu/Documents/zig/zig/src/main.zig:4500:20: 0xa5ed647 in updateModule (zig)
    try comp.update(prog_node);
                   ^
/home/vexu/Documents/zig/zig/src/main.zig:3690:21: 0xa6596e9 in buildOutputType (zig)
        updateModule(comp, color, root_prog_node) catch |err| switch (err) {
                    ^

Self hosted backend stack trace

error(link): NAV a.foo(InternPool.Nav.Index(225)) assigned symbol 14 but not allocated!
thread 553180 panic: reached unreachable code
/home/vexu/Documents/zig/zig/lib/std/debug.zig:518:14: 0xa510f1d in assert (zig)
    if (!ok) unreachable; // assertion failure
             ^
/home/vexu/Documents/zig/zig/src/link/Elf/ZigObject.zig:844:15: 0xaba7ce7 in updateSymtabSize (zig)
        assert(name.len > 0);
              ^
/home/vexu/Documents/zig/zig/src/link/Elf/file.zig:229:50: 0xaba861e in updateSymtabSize (zig)
            inline else => |x| x.updateSymtabSize(elf_file),
                                                 ^
/home/vexu/Documents/zig/zig/src/link/Elf.zig:3765:38: 0xabaa0e2 in updateSymtabSize (zig)
        try file_ptr.updateSymtabSize(self);
                                     ^
/home/vexu/Documents/zig/zig/src/link/Elf/relocatable.zig:294:34: 0xabe17f2 in updateSectionSizes (zig)
    try elf_file.updateSymtabSize();
                                 ^
/home/vexu/Documents/zig/zig/src/link/Elf/relocatable.zig:167:27: 0xabe7e40 in flushObject (zig)
    try updateSectionSizes(elf_file);
                          ^
/home/vexu/Documents/zig/zig/src/link/Elf.zig:854:47: 0xabef426 in flushModuleInner (zig)
        .Obj => return relocatable.flushObject(self, comp),
                                              ^
/home/vexu/Documents/zig/zig/src/link/Elf.zig:829:28: 0xa91ee31 in flushModule (zig)
    return flushModuleInner(self, arena, tid) catch |err| switch (err) {
                           ^
/home/vexu/Documents/zig/zig/src/link/Elf.zig:808:25: 0xa73a4b6 in flush (zig)
    try self.flushModule(arena, tid, prog_node);
                        ^
/home/vexu/Documents/zig/zig/src/link.zig:831:77: 0xa5abb0c in flush (zig)
                return @as(*tag.Type(), @fieldParentPtr("base", base)).flush(arena, tid, prog_node);
                                                                            ^
/home/vexu/Documents/zig/zig/src/Compilation.zig:2438:17: 0xa5ab466 in flush (zig)
        lf.flush(arena, tid, prog_node) catch |err| switch (err) {
                ^
/home/vexu/Documents/zig/zig/src/Compilation.zig:2398:22: 0xa5af671 in update (zig)
            try flush(comp, arena, .{
                     ^
/home/vexu/Documents/zig/zig/src/main.zig:4500:20: 0xa5ed647 in updateModule (zig)
    try comp.update(prog_node);
                   ^
/home/vexu/Documents/zig/zig/src/main.zig:3690:21: 0xa6596e9 in buildOutputType (zig)
        updateModule(comp, color, root_prog_node) catch |err| switch (err) {
                    ^

[Validark]

Hey @Vexu, do you think maybe this should go in the 0.14.0 milestone? This seems like a pretty critical bug.