[PATCH 3/3] 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
  }]

Define and add the missing *host* dependencies to improve the developer
experience. Define the *target* `core` crate using the new
`append_sysroot_crate` helper.

Fixes: 8c4555ccc55c ("scripts: add `generate_rust_analyzer.py`")
Suggested-by: Chayim Refael Friedman <chayimfr@gmail.com>
Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 scripts/generate_rust_analyzer.py | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
index cb49f0b07c97..124f6b0334db 100755
--- a/scripts/generate_rust_analyzer.py
+++ b/scripts/generate_rust_analyzer.py
@@ -92,14 +92,28 @@ def generate_crates(
         )
         return {"crate": index, "name": display_name}
 
-    # First, the ones in `rust/` since they are a bit special.
-    core = append_crate(
-        "core",
-        sysroot_src / "core" / "src" / "lib.rs",
-        [],
-        cfg=crates_cfgs.get("core", []),
-        is_workspace_member=False,
-    )
+    def append_sysroot_crate(
+        display_name: str,
+        deps: list[Dependency],
+        cfg: list[str] = [],
+    ) -> Dependency:
+        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)`.
+    host_core = append_sysroot_crate("core", [])
+    host_alloc = append_sysroot_crate("alloc", [host_core])
+    host_std = append_sysroot_crate("std", [host_alloc, host_core])
+    host_proc_macro = append_sysroot_crate("proc_macro", [host_core, host_std])
+
+    core = append_sysroot_crate("core", [], cfg=crates_cfgs.get("core", []))
 
     compiler_builtins = append_crate(
         "compiler_builtins",
@@ -110,7 +124,7 @@ def generate_crates(
     macros = append_crate(
         "macros",
         srctree / "rust" / "macros" / "lib.rs",
-        [],
+        [host_std, host_proc_macro],
         is_proc_macro=True,
     )
 

-- 
2.48.1