Editing Stack trace (section)

=== Rust ===
[[Rust (programming language)|Rust]] has two types of errors. Functions that use the panic [[Macro (computer science)|macro]] are "unrecoverable" and the current thread will become poisoned experiencing stack unwinding. Functions that return a <code>std::result::Result</code> are "recoverable" and can be handled gracefully.<ref>{{Cite web|title=rustonomicon unwinding - Rust|url=https://doc.rust-lang.org/nomicon/unwinding.html#:~:text=Rust%20has%20a%20tiered%20error,be%20handled%2C%20the%20thread%20panics.|website=doc.rust-lang.org}}</ref> However, recoverable errors cannot generate a stack trace as they are manually added and not a result of a runtime error.

As of June 2021, [[Rust (programming language)|Rust]] has experimental support for stack traces on unrecoverable errors. Rust supports printing to [[stderr]] when a thread panics, but it must be enabled by setting the <code>RUST_BACKTRACE</code> [[environment variable]].<ref>{{Cite web|title=std::backtrace - Rust|url=https://doc.rust-lang.org/std/backtrace/index.html|access-date=2021-06-15|website=doc.rust-lang.org}}</ref>

When enabled, such backtraces look similar to below, with the most recent call first.
<syntaxhighlight lang="rust">
thread 'main' panicked at 'execute_to_panic', main.rs:3
stack backtrace:
   0: std::sys::imp::backtrace::tracing::imp::unwind_backtrace
   1: std::panicking::default_hook::{{closure}}
   2: std::panicking::default_hook
   3: std::panicking::rust_panic_with_hook
   4: std::panicking::begin_panic
   5: futures::task_impl::with
   6: futures::task_impl::park
...
</syntaxhighlight>