[PATCH v3] scripts: generate_rust_analyzer.py: add missing macros deps

[Tamir Duberstein <tamird@gmail.com>]

The macros crate has depended on std and proc_macro since its
introduction in commit 1fbde52bde73 ("rust: add `macros` crate"). These
dependencies were omitted from commit 8c4555ccc55c ("scripts: add
`generate_rust_analyzer.py`") resulting in missing go-to-definition and
autocomplete, and false-positive warnings emitted from rust-analyzer
such as:

  [{
  	"resource": "/Users/tamird/src/linux/rust/macros/module.rs",
  	"owner": "_generated_diagnostic_collection_name_#1",
  	"code": {
  		"value": "non_snake_case",
  		"target": {
  			"$mid": 1,
  			"path": "/rustc/",
  			"scheme": "https",
  			"authority": "doc.rust-lang.org",
  			"query": "search=non_snake_case"
  		}
  	},
  	"severity": 4,
  	"message": "Variable `None` should have snake_case name, e.g. `none`",
  	"source": "rust-analyzer",
  	"startLineNumber": 123,
  	"startColumn": 17,
  	"endLineNumber": 123,
  	"endColumn": 21
  }]

Add the missing dependencies to improve the developer experience.

Fixes: 8c4555ccc55c ("scripts: add `generate_rust_analyzer.py`")
Reviewed-by: Fiona Behrens <me@kloenk.dev>
Suggested-by: Chayim Refael Friedman <chayimfr@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
Changes in v3:
- Avoid shuffling compilter_builtins; it is not needed for RA support.
- Align more closely with the long-term solution:
  https://lore.kernel.org/all/20250209-rust-analyzer-host-v1-0-a2286a2a2fa3@gmail.com/.
- Link to v2: https://lore.kernel.org/r/20250209-rust-analyzer-macros-core-dep-v2-1-897338344d16@gmail.com

Changes in v2:
- Change macros deps from [core] to [std, proc_macro], improving
  autocomplete and go-to-definition.
- Remove Wedson Almeida Filho <wedsonaf@google.com> from cc; email
  bounced.
- Link to v1: https://lore.kernel.org/r/20250209-rust-analyzer-macros-core-dep-v1-1-5ebeb3eb60a9@gmail.com
---
 scripts/generate_rust_analyzer.py | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
index aa8ea1a4dbe5..1394baa5ee9e 100755
--- a/scripts/generate_rust_analyzer.py
+++ b/scripts/generate_rust_analyzer.py
@@ -57,14 +57,26 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
         crates_indexes[display_name] = len(crates)
         crates.append(crate)
 
-    # First, the ones in `rust/` since they are a bit special.
-    append_crate(
-        "core",
-        sysroot_src / "core" / "src" / "lib.rs",
-        [],
-        cfg=crates_cfgs.get("core", []),
-        is_workspace_member=False,
-    )
+    def append_sysroot_crate(
+        display_name,
+        deps,
+        cfg=[],
+    ):
+        return append_crate(
+            display_name,
+            sysroot_src / display_name / "src" / "lib.rs",
+            deps,
+            cfg,
+            is_workspace_member=False,
+        )
+
+    # NB: sysroot crates reexport items from one another so setting up our transitive dependencies
+    # here is important for ensuring that rust-analyzer can resolve symbols. The sources of truth
+    # for this dependency graph are `(sysroot_src / crate / "Cargo.toml" for crate in crates)`.
+    append_sysroot_crate("core", [], cfg=crates_cfgs.get("core", []))
+    append_sysroot_crate("alloc", ["core"])
+    append_sysroot_crate("std", ["alloc", "core"])
+    append_sysroot_crate("proc_macro", ["core", "std"])
 
     append_crate(
         "compiler_builtins",
@@ -75,7 +87,7 @@ def generate_crates(srctree, objtree, sysroot_src, external_src, cfgs):
     append_crate(
         "macros",
         srctree / "rust" / "macros" / "lib.rs",
-        [],
+        ["std", "proc_macro"],
         is_proc_macro=True,
     )
 

---
base-commit: 6273a058383e05465083b535ed9469f2c8a48321
change-id: 20250209-rust-analyzer-macros-core-dep-0f57868dd19f

Best regards,
-- 
Tamir Duberstein <tamird@gmail.com>