Rust: Restore built-in derive macro expansion under rust-analyzer 0.0.328

[redsun82]

Stacked on #21714 (the rust-analyzer 0.0.328 upgrade).

That upgrade silently drops built-in derive macro expansion — something we'd already spotted as a team: the impl blocks synthesized by #[derive(Debug)], #[derive(PartialEq, Eq)], etc. are no longer extracted. rust-analyzer 0.0.317 re-modeled built-in derives as synthetic impls rather than syntactic macro expansions, so Semantics::expand_derive_macro returns None for them and our old .flatten().flatten() just dropped them on the floor.

This regresses any query that leans on the derived impls (rust/insecure-cookie is the one that first flagged it: it went from 1 result to 0).

Approach

Rather than reverting the parts of the upgrade that fix the Rust 1.95 breakage, I reconstruct the expansions extractor-side:

• re-run the still-public built-in derive expander (ra_ap_hir_expand::builtin::BuiltinDeriveExpander) over the ADT and emit the resulting impl items ourselves, reusing the existing emit_macro_items path
• the synthesized nodes aren't registered in the semantics cache (so Semantics::original_range would panic on them), so I route their locations through the expansion span map via map_node_range_up_rooted for the duration of the emission
• resolve_derive_macro is used positionally alongside expand_derive_macro to tell the built-in derives apart from proc-macro ones and recover the right expander

This needed one new direct dep on ra_ap_syntax-bridge (already vendored transitively). The bazel 3rdparty wiring was regenerated with rust/update_cargo_deps.sh.

Validation

• the macro-expansion extractor test now shows the built-in derive impls again (impl ...::Eq for MyDeriveEnum and friends)
• CWE-614/InsecureCookie.expected now matches the pre-upgrade main baseline exactly, so the regression is fully undone
• type-inference.expected picks up a handful of newly-resolved ::default()/constructor results (and loses the corresponding Missing result: markers), which is a nice side effect of Default being back
• the rest of the impacted expectations (canonical_path, MacroItems) are just the restored derive rows; 360+ other affected rust tests still pass locally

Marking as draft to let CI have a full go at the test suite. I couldn't reproduce the Rust 1.95 side locally (no 1.95 toolchain here), but that half of the upgrade is preserved by construction since the fix lives entirely inside the extractor's use of the 0.0.328 crates.

[Copilot]

Pull request overview

Restores extraction of rust-analyzer’s synthesized built-in derive implementations.

Changes:

• Reconstructs built-in derive expansions and maps synthesized locations.
• Adds the syntax-bridge dependency and Bazel wiring.
• Updates affected extraction, type-inference, and security expectations.

Show a summary per file

File	Description
rust/extractor/src/translate/base.rs	Implements derive reconstruction and location mapping.
rust/extractor/Cargo.toml	Adds syntax-bridge dependency.
Cargo.lock	Locks the new dependency.
MODULE.bazel	Exposes the vendored dependency.
misc/bazel/3rdparty/tree_sitter_extractors_deps/defs.bzl	Wires the dependency into Bazel.
misc/bazel/3rdparty/tree_sitter_extractors_deps/BUILD.bazel	Adds dependency aliases.
rust/ql/test/extractor-tests/macro-expansion/test.expected	Verifies restored derive items.
rust/ql/test/extractor-tests/macro-expansion/PrintAst.expected	Records synthesized derive ASTs.
rust/ql/test/extractor-tests/generated/MacroItems/MacroItems.expected	Records derived macro items.
rust/ql/test/extractor-tests/canonical_path/canonical_paths.expected	Verifies canonical paths for derived impls.
rust/ql/test/library-tests/type-inference/type-inference.expected	Records improved type inference.
rust/ql/test/query-tests/security/CWE-614/InsecureCookie.expected	Restores insecure-cookie results.

Review details

• Files reviewed: 10/12 changed files
• Comments generated: 1
• Review effort level: Balanced