This is a tracking issue for the RFC "Fix the Error trait" (rust-lang/rfcs#2504).

Steps:

• Implement the RFC (cc @rust-lang/libs)
  • source method Add Error::source method per RFC 2504. #53533
  • Backtrace API std: Add a backtrace module #64154
• Implement proof of concept showing stabilizing backtrace method won't prevent moving Error into core later Start working on proof of concept for exposing Backtrace in core #77384
• Fix std::backtrace::Backtrace's fmt representations
  • Precision flag support Formatting of std::backtrace::Backtrace #65280 this is non-blocking for stabilization
  • Differences with panic! backtraces Backtrace rendering inconsistent between std::backtrace and panics #71706
• Adjust documentation (see instructions on forge)
• Stabilization PR (see instructions on forge)

Unresolved questions:

• The choice to implement nullability internal to backtrace may prove to be a mistake: during the period when backtrace APIs are only available on nightly, we will gain more experience and possible change backtrace's constructors to return an Option<Backtrace> instead.

Current status:

#53487 (comment)