# Segmentation fault with Dict

**URL:** <https://forum.modular.com/t/segmentation-fault-with-dict/1656>\
**Category:** Mojo\
**Created:** [June 14, 2025, 6:07pm UTC](https://forum.modular.com/t/segmentation-fault-with-dict/1656 "2025-06-14T18:07:58Z")\
**Posts on this page:** 1\
**Showing post:** 12

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**Author:** ![duck\_tape](https://sea1.discourse-cdn.com/flex001/user_avatar/forum.modular.com/duck_tape/32/432_2.png) [@duck\_tape](https://forum.modular.com/u/duck_tape)\
**Post date:** [June 17, 2025, 1:17pm UTC](https://forum.modular.com/t/segmentation-fault-with-dict/1656/12 "2025-06-17T13:17:33Z")

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[[stdlib] Fix int formatting to not go out of bounds, add MIN and MAX for 128 and 256 sized integers by sstadick · Pull Request #4852 · modular/modular · GitHub](https://github.com/modular/modular/pull/4852#issue-3153481339) fixes both this issue, and the original issue [UInt256 returns wrong value - #6 by sora](https://forum.modular.com/t/uint256-returns-wrong-value/1643/6).

The tests show the fix for format\_int working. I also checked that:

```mojo
fn main():
    var number = Dict[String, Int128]()
    for idx in range(2):
        number[String(idx)] = Int128(idx)

```

failed before the fix and works after.

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