[PATCH v2 2/2] scripts: generate_rust_analyzer: fix IDE support for primitive types

[Jesung Yang via B4 Relay <devnull+y.j3ms.n.gmail.com@kernel.org>]

From: Jesung Yang <y.j3ms.n@gmail.com>

Update `generate_rust_analyzer.py` so that the generated
`rust-project.json` contains the `sysroot_src` field with
`"crate_attrs": ["no_std"]` specified for relevant crates. This ensures
that rust-analyzer provides proper IDE support for inherent methods of
primitive types.

Since commit 50384460c68f ("Rewrite method resolution to follow rustc
more closely") to rust-analyzer, it no longer provides language server
features like code completion and go-to-definition for inherent methods
of primitive types when sysroot crates (e.g., `core`, `std`) are inlined
in `rust-project.json` [1]. As `generate_rust_analyzer.py` currently
inlines these crates, our setup is affected by this change.

Specifying the `sysroot_src` field restores this functionality by
allowing rust-analyzer to locate sysroot crates by itself. However, this
causes `std` to be treated as a dependency for all local crates by
default. To align with our compilation settings, provide the `no_std`
attribute via the `crate_attrs` field, as the `-Zcrate-attr=no_std`
compiler flag is not visible to rust-analyzer. This combined approach
removes manual manipulation of sysroot dependencies while preventing
incorrect symbol resolution against the standard library.

Note that this configuration requires rust-analyzer release 2025-12-22
(v0.3.2727) or later, which introduced support for the `crate_attrs`
field.

Link: https://rust-lang.zulipchat.com/#narrow/channel/x/topic/x/near/561607963 [1]
Link: https://rust-for-linux.zulipchat.com/#narrow/channel/x/topic/x/near/561607753
Signed-off-by: Jesung Yang <y.j3ms.n@gmail.com>
---
 scripts/generate_rust_analyzer.py | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
index 32b0da99f17549ecc83e9a68911373310a2c9617..6c3cb1d65d97e0ec414192f9fb867700a99c3d57 100755
--- a/scripts/generate_rust_analyzer.py
+++ b/scripts/generate_rust_analyzer.py
@@ -234,13 +234,16 @@ class RaVersion(enum.Enum):
 
     # v0.3.1940, released on 2024-04-29; bundled with the rustup 1.78 toolchain.
     V20240429 = 0
+    # v0.3.2727, released on 2025-12-22.
+    V20251222 = 1
 
     @staticmethod
     def baselines():
-        assert len(RaVersion) == 1, "Exhaustiveness check: update baseline list!"
+        assert len(RaVersion) == 2, "Exhaustiveness check: update checkpoint list!"
 
         return [
             (datetime.strptime("2024-04-29", "%Y-%m-%d"), (0, 3, 1940), RaVersion.V20240429),
+            (datetime.strptime("2025-12-22", "%Y-%m-%d"), (0, 3, 2727), RaVersion.V20251222),
         ]
 
     @staticmethod
@@ -249,10 +252,12 @@ class RaVersion(enum.Enum):
         return RaVersion.V20240429
 
     def __str__(self):
-        assert len(RaVersion) == 1, "Exhaustiveness check: update if branches!"
+        assert len(RaVersion) == 2, "Exhaustiveness check: update if branches!"
 
         if self == RaVersion.V20240429:
             return "v0.3.1940 (2024-04-29)"
+        elif self == RaVersion.V20251222:
+            return "v0.3.2727 (2025-12-22)"
         else:
             assert False, "Unreachable"
 
@@ -266,7 +271,7 @@ def generate_rust_project(
     cfgs,
     core_edition
 ):
-    assert len(RaVersion) == 1, "Exhaustiveness check: update if branches!"
+    assert len(RaVersion) == 2, "Exhaustiveness check: update if branches!"
 
     if ra_version == RaVersion.V20240429:
         ctx = {
@@ -277,6 +282,16 @@ def generate_rust_project(
             "crates": generate_crates(ctx, srctree, objtree, sysroot_src, external_src, cfgs, core_edition),
             "sysroot": str(sysroot),
         }
+    elif ra_version == RaVersion.V20251222:
+        ctx = {
+            "use_crate_attrs": True,
+            "add_sysroot_crates": False,
+        }
+        return {
+            "crates": generate_crates(ctx, srctree, objtree, sysroot_src, external_src, cfgs, core_edition),
+            "sysroot": str(sysroot),
+            "sysroot_src": str(sysroot_src),
+        }
     else:
         assert False, "Unreachable"
 

-- 
2.47.3