allocPrint causes segfault when compiling

[GoWind]

Zig Version

0.10.0-dev.3050+e05487746

Steps to Reproduce

The following code fails to compile and causes a segmentation fault on linux x86_64 when run with zig test

pub const State = struct { label: ?u8 = null, out: ?*State = null, out1: ?*State = null };
pub const NFA = struct { initial: *State, accept: *State };

//return a string representing the dotviz
  //representation of the NFA
  fn printNFA(a: Allocator, n: NFA) ![]u8 {
      var seen_set = StateSet.init(a);
      var state_queue = ArrayList(*State).init(a);
      var nfa_string = try fmt.allocPrint(a, "digraph G {{", .{});
      var initial = n.initial;
      try state_queue.append(initial);
      while (state_queue.items.len > 0) {
          var item = state_queue.items[0];
          var split: u8 = '-';
          if (seen_set.contains(item) == false) {
              if (item.out != null) {
                  try state_queue.append(item.out.?);
                  nfa_string = try fmt.allocPrintZ(a, "{s} \n {c} -> {c}", .{ nfa_string, item.label orelse split, item.out.?.label orelse sp  lit });
              }
              if (item.out1 != null) {
                  try state_queue.append(item.out1.?);
                  nfa_string = try fmt.allocPrintZ(a, "{s} \n {c} -> {c}", .{ nfa_string, item.label orelse split, item.out1.?.label orelse s  plit });
              }
              try seen_set.put(item, true);
          }
          _ = state_queue.orderedRemove(0);
      }
      nfa_string = try fmt.allocPrint(a, "{s} }}", .{nfa_string});
      return nfa_string;
  }
  
  test "printNFA test" {
      var t = std.testing.allocator;
      var arena = std.heap.ArenaAllocator.init(t);
      defer arena.deinit();
      var h = arena.allocator();
      var c = State{ .label = 'c', .out = null, .out1 = null };
      var b = State{ .label = 'b', .out = null, .out1 = null };
      var a = State{ .label = 'a', .out = &b, .out1 = &c };
      var nfa = NFA{ .initial = &a, .accept = &c };
      var nfa_string = try printNFA(t, nfa);
      var expected_nfa = "digraph G { a -> b \n a -> c }".*;
      defer h.free(nfa_string);
      try std.testing.expectEqualStrings(nfa_string, &expected_nfa);
  }

Expected Behavior

i expect the code to compile or tell me what the error is , if any

Actual Behavior

broken LLVM module found: Instruction does not dominate all uses!
%68 = getelementptr inbounds %"struct:305:75", %"struct:305:75"* %10, i32 0, i32 1, !dbg !4329
store i8 %70, i8* %68, align 1, !dbg !4328
Instruction does not dominate all uses!
%76 = getelementptr inbounds %"struct:305:75", %"struct:305:75"* %10, i32 0, i32 2, !dbg !4332
store i8 %78, i8* %76, align 1, !dbg !4333
Instruction does not dominate all uses!
%108 = getelementptr inbounds %"struct:309:75", %"struct:309:75"* %15, i32 0, i32 1, !dbg !4346
store i8 %110, i8* %108, align 1, !dbg !4345
Instruction does not dominate all uses!
%116 = getelementptr inbounds %"struct:309:75", %"struct:309:75"* %15, i32 0, i32 2, !dbg !4349
store i8 %118, i8* %116, align 1, !dbg !4350

This is a bug in the Zig compiler.thread 8584 panic:
Unable to dump stack trace: debug info stripped

[Vexu]

Duplicate of #3882