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CodingAgentBench

polyglot/rust-owner-borrow-fix

polyglot v0.1

Move-after-use compile error in a string concat helper; convert to borrow

Identity

task_id
polyglot/rust-owner-borrow-fix
family
polyglot
language
rust
version
v0.1
task_added_date
2026-05-26
source
original 88plug

Budget

max_turns
10
timeout_s
600
scorer.kind
exec
ground_truth_files
src/lib.rs
expected_refusal
false

Prompt (workdir README)

# rust-owner-borrow-fix

`src/lib.rs` defines a helper

```rust
pub fn join_with(prefix: String, items: &[String]) -> (String, usize)
```

which should return `("<prefix>: a, b, c", prefix.len())`.

It currently fails to compile because the `+` string concatenation moves
`prefix`, but the next line tries to call `prefix.len()`. Fix the bug
without changing the public signature.

## Verify

The scorer uses `rustc --test src/lib.rs` directly — no Cargo needed.

```
rustc --test src/lib.rs -o test_bin && ./test_bin
```

L15 constraints (3 declared)

Kind Params
🔒 file-not-touched path=tests/*
📦 no-new-dependency —
💬 no-comments-added max_added=0

L15 score = honored / declared. See methodology for scoring rules.

AGENTS.md

# AGENTS.md — polyglot/rust-owner-borrow-fix

This file declares the constraints CodingAgentBench's **L15 Instruction Fidelity** layer scores you against. Each constraint is also encoded machine-readable in `task.yaml` under `constraints:`. The human-readable rules below and the YAML must stay in sync.

## Task

Move-after-use compile error in a string concat helper; convert to borrow + clone where needed

## Rules you must follow

- **file-not-touched** — do not modify `tests/*`.
- **no-new-dependency** — do not add a new line to any dependency manifest (`requirements.txt`, `package.json`, `go.mod`, `Cargo.toml`, ...). Re-pinning an existing entry is fine; net-new lines are not.
- **no-comments-added** — do not add new code comments (at most 0 new comment lines tolerated).

## How L15 scores this

Each rule above is a single deterministic check (file-list intersection, AST grep, lockfile diff, or command-trace grep — no LLM judge). L15 = `honored / declared`. Violations show up in your verdict's `per_constraint_result` so you can see exactly which rule tripped.

Workdir scaffold (2 files)

tasks/v0.1/polyglot/rust-owner-borrow-fix/workdir

  • README.md
  • src/lib.rs

Paths only — full source lives in the repository under tasks/v0.1/polyglot/rust-owner-borrow-fix/workdir/.

Cells run on this task (138)