returning `@errorCast` from an inline inferred error set function crashes the compiler

[andrewrk]

Zig Version

0.12.0-dev.705+af40bce08

Steps to Reproduce and Observed Behavior

const std = @import("std");

test {
    std.testing.expect((try baz()) == 1234);
}

inline fn baz() !i32 {
    return @errorCast(foo());
}

fn foo() anyerror!i32 {
    return 1234;
}

$ stage4/bin/zig test test3.zig 
thread 1049973 panic: reached unreachable code
Analyzing test3.zig: test3.zig:baz
      %34 = dbg_block_begin()
      %35 = dbg_stmt(2, 5)
      %36 = ret_type() node_offset:8:5 to :8:29
      %37 = dbg_stmt(2, 12)
      %38 = decl_val("foo") token_offset:8:23 to :8:26
      %39 = dbg_stmt(2, 26)
      %40 = call(.auto, %38, []) node_offset:8:23 to :8:28
    > %41 = extended(error_cast(%36, %40)) node_offset:8:12 to :8:29
      %42 = as_node(%36, %41) node_offset:8:12 to :8:29
      %43 = dbg_stmt(2, 5)
      %44 = ret_node(%42) node_offset:8:5 to :8:29
      %45 = dbg_block_end()
      %46 = restore_err_ret_index(%33, %4294967211)
      %47 = break(%33, @InternPool.Index.void_value)
    For full context, use the command
      zig ast-check -t test3.zig

  in test3.zig: test3.zig:baz
    > %33 = block({%34..%47}) node_offset:7:22 to :7:22
  in test3.zig: test3.zig:test_0
    > %17 = call(.auto, %15, []) node_offset:4:29 to :4:34
  in test3.zig: test3.zig:test_0
    > %13 = field_call(nodiscard .auto, %10, "expect", [
        {%14..%24},
      ]) node_offset:4:5 to :4:44
  in test3.zig: test3.zig:test_0
    > %5 = block({%6..%27}) node_offset:3:6 to :3:6

/home/andy/Downloads/zig/src/type.zig:2878:21: 0x691d4fc in errorSetNames (zig)
            else => unreachable,
                    ^
/home/andy/Downloads/zig/src/Sema.zig:21781:63: 0x6c9ba49 in zirErrorCast (zig)
        if (!dest_ty.isAnyError(mod) and dest_ty.errorSetNames(mod).len == 0) break :disjoint true;
                                                              ^
/home/andy/Downloads/zig/src/Sema.zig:1255:65: 0x68d024f in analyzeBodyInner (zig)
                    .error_cast         => try sema.zirErrorCast(         block, extended),
                                                                ^
/home/andy/Downloads/zig/src/Sema.zig:5887:34: 0x72841bb in resolveBlockBody (zig)
        if (sema.analyzeBodyInner(child_block, body)) |_| {
                                 ^
/home/andy/Downloads/zig/src/Sema.zig:5870:33: 0x6ccc160 in zirBlock (zig)
    return sema.resolveBlockBody(parent_block, src, &child_block, body, inst, &label.merges);
                                ^
/home/andy/Downloads/zig/src/Sema.zig:1578:49: 0x68d7947 in analyzeBodyInner (zig)
                    break :blk try sema.zirBlock(block, inst, tags[inst] == .block_comptime);
                                                ^
/home/andy/Downloads/zig/src/Sema.zig:917:30: 0x6b9ff78 in analyzeBody (zig)
    _ = sema.analyzeBodyInner(block, body) catch |err| switch (err) {
                             ^
/home/andy/Downloads/zig/src/Sema.zig:7505:33: 0x71d05bf in analyzeCall (zig)
                sema.analyzeBody(&child_block, fn_info.body) catch |err| switch (err) {
                                ^
/home/andy/Downloads/zig/src/Sema.zig:6725:43: 0x6c02814 in zirCall__anon_154030 (zig)
    const call_inst = try sema.analyzeCall(block, func, func_ty, callee_src, call_src, modifier, ensure_result_used, args_info, call_dbg_node, .call);
                                          ^
/home/andy/Downloads/zig/src/Sema.zig:1029:62: 0x68c6ba0 in analyzeBodyInner (zig)
            .call                         => try sema.zirCall(block, inst, .direct),
                                                             ^
/home/andy/Downloads/zig/src/Sema.zig:934:45: 0x666a681 in analyzeBodyBreak (zig)
    const break_inst = sema.analyzeBodyInner(block, body) catch |err| switch (err) {
                                            ^
/home/andy/Downloads/zig/src/Sema.zig:883:50: 0x71c71b3 in resolveBody (zig)
    const break_data = (try sema.analyzeBodyBreak(block, body)) orelse
                                                 ^
/home/andy/Downloads/zig/src/Sema.zig:7014:59: 0x76231c5 in analyzeArg (zig)
                const uncoerced_arg = try sema.resolveBody(block, arg_body, zir_call.call_inst);
                                                          ^
/home/andy/Downloads/zig/src/Sema.zig:7569:49: 0x71d165b in analyzeCall (zig)
            arg_out.* = try args_info.analyzeArg(sema, block, arg_idx, param_ty, func_ty_info, func);
                                                ^
/home/andy/Downloads/zig/src/Sema.zig:6725:43: 0x6c03a68 in zirCall__anon_154031 (zig)
    const call_inst = try sema.analyzeCall(block, func, func_ty, callee_src, call_src, modifier, ensure_result_used, args_info, call_dbg_node, .call);
                                          ^
/home/andy/Downloads/zig/src/Sema.zig:1030:62: 0x68c6c5c in analyzeBodyInner (zig)
            .field_call                   => try sema.zirCall(block, inst, .field),
                                                             ^
/home/andy/Downloads/zig/src/Sema.zig:5887:34: 0x72841bb in resolveBlockBody (zig)
        if (sema.analyzeBodyInner(child_block, body)) |_| {
                                 ^
/home/andy/Downloads/zig/src/Sema.zig:5870:33: 0x6ccc160 in zirBlock (zig)
    return sema.resolveBlockBody(parent_block, src, &child_block, body, inst, &label.merges);
                                ^
/home/andy/Downloads/zig/src/Sema.zig:1578:49: 0x68d7947 in analyzeBodyInner (zig)
                    break :blk try sema.zirBlock(block, inst, tags[inst] == .block_comptime);
                                                ^
/home/andy/Downloads/zig/src/Sema.zig:917:30: 0x6b9ff78 in analyzeBody (zig)
    _ = sema.analyzeBodyInner(block, body) catch |err| switch (err) {
                             ^
/home/andy/Downloads/zig/src/Module.zig:4847:21: 0x68a4826 in analyzeFnBody (zig)
    sema.analyzeBody(&inner_block, fn_info.body) catch |err| switch (err) {
                    ^
/home/andy/Downloads/zig/src/Module.zig:3442:40: 0x664a7fd in ensureFuncBodyAnalyzed (zig)
            var air = mod.analyzeFnBody(func_index, sema_arena) catch |err| switch (err) {
                                       ^
/home/andy/Downloads/zig/src/Compilation.zig:3458:42: 0x66488cd in processOneJob (zig)
            module.ensureFuncBodyAnalyzed(func) catch |err| switch (err) {
                                         ^
/home/andy/Downloads/zig/src/Compilation.zig:3395:30: 0x647bf5b in performAllTheWork (zig)
            try processOneJob(comp, work_item, main_progress_node);
                             ^
/home/andy/Downloads/zig/src/Compilation.zig:2194:31: 0x64774ec in update (zig)
    try comp.performAllTheWork(main_progress_node);
                              ^
/home/andy/Downloads/zig/src/main.zig:4194:24: 0x64a6530 in updateModule (zig)
        try comp.update(main_progress_node);
                       ^
/home/andy/Downloads/zig/src/main.zig:3597:17: 0x64c96c1 in buildOutputType (zig)
    updateModule(comp) catch |err| switch (err) {
                ^
/home/andy/Downloads/zig/src/main.zig:275:31: 0x631dba7 in mainArgs (zig)
        return buildOutputType(gpa, arena, args, .zig_test);
                              ^
/home/andy/Downloads/zig/src/main.zig:213:20: 0x631ac05 in main (zig)
    return mainArgs(gpa, arena, args);
                   ^
/home/andy/Downloads/zig/lib/std/start.zig:486:37: 0x631a61e in main (zig)
    std.os.argv = @as([*][*:0]u8, @ptrCast(c_argv))[0..@as(usize, @intCast(c_argc))];
                                    ^
???:?:?: 0x7f8f2920dacd in ??? (libc.so.6)
Unwind information for `libc.so.6:0x7f8f2920dacd` was not available, trace may be incomplete

Aborted (core dumped)

Expected Behavior

Test passed.