# How to debug an error in "type inference"

**URL:** <https://discourse.julialang.org/t/how-to-debug-an-error-in-type-inference/126122>\
**Category:** General Usage\
**Tags:** package-extensions\
**Created:** [February 20, 2025, 4:49pm UTC](https://discourse.julialang.org/t/how-to-debug-an-error-in-type-inference/126122 "2025-02-20T16:49:17Z")\
**Posts on this page:** 1\
**Showing post:** 8

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**Author:** ![sgaure](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/sgaure/32/14779_2.png) [@sgaure](https://discourse.julialang.org/u/sgaure)\
**Post date:** [February 21, 2025, 2:18pm UTC](https://discourse.julialang.org/t/how-to-debug-an-error-in-type-inference/126122/8 "2025-02-21T14:18:44Z")

</div>

gdb is start from the command line:

```julia
gdb julia
...
...
(gdb) run
...
...
julia> 

```

The `run` command can take the arguments you normally start julia with, e.g. `run -t 4 --startup=no` etc.  
When you interrupt the program you are returned to the `(gdb)` prompt, and can type `where`, to obtain a stack dump. gdb is very low level.

The list you get from --trace-compile says which precompilations have been started, but they run in parallel, so it’s not necessarily the last one which hangs. This may also be the reason things continue after interrupt, it might be the case that only one of the threads are interrupted, and then releases some resource which the others need. You can try starting julia with `-t 1` to run serially (I think that works for precompilations too).

Have you tried running with julia 1.10.8?

I’m in deep water here, someone with more knowledge about the internals of julia compilation should have a look at this.

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