Follow symlinks when scanning the sysroot for proc-macro dylibs - #23297
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Follow symlinks when scanning the sysroot for proc-macro dylibs#23297onlycs wants to merge 1 commit into
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The scan of the target libdir for rustc_macros & co. used DirEntry::file_type(), which does not follow symlinks. Toolchains assembled out of symlinks (e.g. by nix / oxalica's rust-overlay) link every dylib into the sysroot, so all proc-macro dylibs were skipped. As a result `rustc_queries!` never expanded for rustc_private projects and the macro-generated TyCtxt query getters (`tcx.mir_keys(())` etc.) did not resolve at all. Use fs::metadata, which traverses symlinks, instead. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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This was referenced Sep 4, 2026
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Problem
With a nix toolchain, every macro-generated
TyCtxtquery getter (tcx.mir_keys(()), e.g.) resolves to{unknown}. Three independent bugs cause this, one of which was fixed in 7015591, one with #23296, and one in this PRsymlinked proc-macro dylibs are skipped
WorkspaceBuildScripts::rustc_cratesscans the target libdir for the prebuilt proc-macro dylibs (librustc_macros.so& co.) usingDirEntry::file_type(), which does not follow symlinks. Nix sysroots symlink every file into place, so all dylibs were filtered out. Withoutrustc_macros,rustc_queries!never expands, the generatedrustc_with_all_queriesmacro doesn't exist, and none ofdefine_callbacks!'s output (those macro-generated query getters) is ever created.The fix here was to just use
fs::metadatawhich traverses symlinks.AI disclosure
These changes were authored with AI assistance (Claude Code); the commits carry
Co-Authored-Bytrailers. I have reviewed the changes, use them in a current project using a patched build, and can answer questions about them myself.See also: #23251
Version Info
cargo:
cargo 1.99.0-nightly (eb98b54bc 2026-08-11)Toolchain:
nightly-2026-08-14, componentsrustc-dev,llvm-tools-preview,rust-src.Configuration (Zed,
.zed/settings.json):{ "lsp": { "rust-analyzer": { "initialization_options": { "rustc": { "source": "discover" } } } } }