# The data backtrace?

**URL:** <https://internals.rust-lang.org/t/the-data-backtrace/10644>\
**Category:** tools and infrastructure\
**Created:** [July 31, 2019, 5:03am UTC](https://internals.rust-lang.org/t/the-data-backtrace/10644 "2019-07-31T05:03:46Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![cheako](https://avatars.discourse-cdn.com/v4/letter/c/dc4da7/32.png) [@cheako](https://internals.rust-lang.org/u/cheako)\
**Post date:** [July 31, 2019, 5:03am UTC](https://internals.rust-lang.org/t/the-data-backtrace/10644/1 "2019-07-31T05:03:46Z")

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I don't know if this exists but, given rust, I think it'll be important to have. I was just debugging an issue where a value passed to a function was not correct and I needed to know where it was changed. Because of the borrow checker it could be unlikely this would appear in a stack frame backtrace!

Thus it's important to have a tool that would be able to list where a value comes from.

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**Author:** ![kornel](https://sea2.discourse-cdn.com/flex002/user_avatar/internals.rust-lang.org/kornel/32/2711_2.png) [@kornel](https://internals.rust-lang.org/u/kornel)\
**Post date:** [July 31, 2019, 8:56am UTC](https://internals.rust-lang.org/t/the-data-backtrace/10644/2 "2019-07-31T08:56:05Z")

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This is something that `rr` can do: [https://rr-project.org/](https://rr-project.org/)

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**Author:** ![system](https://sea2.discourse-cdn.com/flex002/user_avatar/internals.rust-lang.org/system/32/14092_2.png) [@system](https://internals.rust-lang.org/u/system)\
**Post date:** [October 29, 2019, 9:06am UTC](https://internals.rust-lang.org/t/the-data-backtrace/10644/3 "2019-10-29T09:06:05Z")

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