Sample
anyhow 1.0.104: Downcasting boxed trait objects in anyhow::Error fails silently because TypeId retains the outer Box, while .context() unwraps transparently and into_boxed_dyn_error bridges back to std::error::Error
Verified sample for cargo anyhow 1.0.104: Downcasting boxed trait objects in anyhow::Error fails silently because TypeId retains the outer Box, while…
sha256:20e1cdba6a0530ce2eb2d690a9875d1bd7e4dc58555b8d124b9beae90ab9dfa5
This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured.
How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people.
MIT-0
Execution evidence
The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.
- Evidence basis
- Signed contract pass
- Verification receipts
- 2
- Signing keys that built it
- 2
Declared environment
rust linux x64 rust rust cargo
Verification-run environments
| Environment | Contract | Stages | Run |
|---|---|---|---|
| rust 1 · linux alpine/x64 · docker ed25519:d91480838ac982c9 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · cargo@1 |
2026-08-16 |
| rust 1 · linux alpine/x64 · docker ed25519:2175b912ea1c23b1 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · cargo@1 |
2026-08-18 |
Case
HOW- Goal
- Downcasting boxed trait objects in anyhow::Error fails silently because TypeId retains the outer Box, while .context() unwraps transparently and into_boxed_dyn_error bridges back to std::error::Error
- Packages
- Symbols
-
- anyhow::Error::from_boxed
- anyhow::Error::downcast_ref
- anyhow::Error::context
- anyhow::Error::into_boxed_dyn_error
- Environment
- rust
- Created
- 2026-08-16T07:54:48Z
Contract
- assert Error::from_boxed wraps Box<dyn StdError> such that downcast_ref to inner concrete type returns None
- assert recovering concrete error from boxed anyhow::Error requires explicit two-step downcast through Box<dyn StdError>
- assert anyhow context wrappers are transparently traversed by downcast_ref
- assert into_boxed_dyn_error converts anyhow::Error into Box<dyn std::error::Error> with preserved source chain
- assert Display prints top context while alternate Display joins chain and Debug formats Caused by section
Files
- Cargo.lock
- Cargo.toml
- NOTES.md
- csx.json
- src/lib.rs