//! Slice 33 of #500: trybuild UI assertions for the `BrokeredBackend`
//! trait shape (#497).
//!
//! Each `tests/ui/brokered_backend_*.rs` file documents one misuse
//! pattern the trait is supposed to prevent (e.g. smuggling state into
//! `bind`). trybuild compiles each file and matches the actual rustc
//! stderr against the recorded `*.stderr` snapshot.
//!
//! These tests are inherently sensitive to rustc diagnostic wording.
//! If the diagnostics change across toolchain updates, re-run with
//! `TRYBUILD=overwrite cargo test --test brokered_backend_ui` to
//! refresh the snapshots, then audit the diff in code review.
//!
//! The harness only runs on the `client` feature (which gates the
//! `broker` module). Skipped on builds that drop the feature.
// TODO: trybuild emits the source-file path in its diagnostic relative to
// whatever CWD it was invoked from. The recorded snapshot is therefore
// pinned to ONE invocation shape (e.g. `cargo nextest run -p running-process`
// from the workspace root yields a different path prefix than `cargo
// llvm-cov nextest --workspace` from the same root). Both the `coverage`
// job and the consolidated `unit-test` jobs (PR #514) ran this test under
// different shapes and saw different actual paths, so neither single
// recorded snapshot satisfies both. Skipping until the snapshot is
// regenerated under a consistent invocation shape — see follow-up.