Prelude not imported in rustc_span

[jonas-schievink]

When editing https://github.com/rust-lang/rust/blob/e1ff91f439bc09f566da211c6449821b4e949279/compiler/rustc_span/src/lib.rs, items from the libstd prelude don't seem to be in scope (including macros exported via #[macro_export]). Manually accessing items from libstd and libcore does work, though.

Looking at the code we use to inject the prelude, this looks a bit questionable, since it relies on the order of dependencies:

https://github.com/rust-analyzer/rust-analyzer/blob/312f1fe20a6a0a8e69834c66f51b9abc9db5e0ce/crates/hir_def/src/nameres/collector.rs#L67-L73

However, this could also be caused by us not handling "cyclic" dev-dependencies correctly, because I see this in the output:

[ERROR project_model::workspace] cyclic deps: rustc_std_workspace_core(CrateId(1165)) -> core(CrateId(191))
[ERROR project_model::workspace] cyclic deps: rustc_std_workspace_core(CrateId(1165)) -> core(CrateId(191))
[ERROR project_model::workspace] cyclic deps: rustc_std_workspace_core(CrateId(1165)) -> core(CrateId(191))