fix(rust): only land a use rooted in this crate

The review bot is right that `use serde::Serialize;` should not land on a
local `Serialize`. Leaving out std/core/alloc was not enough: any other
crate has the same problem. A `use` is now resolved only when its path
starts at `crate`, `self` or `super`.

(cherry picked from commit ee27336a4f)

graphify/extractors/rust.py

@@ -723,8 +723,9 @@ def extract_rust(path: Path) -> dict:
             if arg:
                 def name_use(written: str, path: str) -> None:
                     # The name as written, for the corpus rewire (#4439): the id folds its
-                    # case. Not for the standard library, whose `File` is never the corpus's.
-                    if path.lstrip(": ").split("::")[0].strip() not in ("std", "core", "alloc"):
+                    # case. Only for a path rooted in this crate: `serde::Serialize` or
+                    # `std::fs::File` is never the corpus's own `Serialize` or `File`.
+                    if path.lstrip(": ").split("::")[0].strip() in ("crate", "self", "super"):
                         edges[-1]["_rust_use_name"] = written.split(" as ")[0].strip()
                 module_name = _rust_use_module(_read_text(arg, source))
                 grouped = arg.type in ("use_list", "scoped_use_list")

tests/test_rust_use_trees.py

@@ -236,8 +236,10 @@ def test_a_use_of_a_name_declared_twice_stays_unresolved(tmp_path: Path):
     assert _imports(result, "user.rs") == ["thing"]
 
 
-def test_a_std_use_does_not_land_on_a_same_named_declaration(tmp_path: Path):
+def test_a_use_from_another_crate_does_not_land_on_a_same_named_declaration(tmp_path: Path):
+    """Only a path rooted at `crate`, `self` or `super` names this crate's own item."""
     result = _extract(tmp_path, {
-        "src/lib.rs": "pub mod a;\npub mod user;\n", "src/a.rs": "pub struct File;\npub struct Command;\n",
-        "src/user.rs": "use std::fs::File;\nuse std::{process::Command, io};\n"})
-    assert _imports(result, "user.rs") == ["command", "file", "io"]
+        "src/lib.rs": "pub mod a;\npub mod user;\n",
+        "src/a.rs": "pub struct File;\npub struct Command;\npub struct Serialize;\n",
+        "src/user.rs": "use std::fs::File;\nuse std::{process::Command, io};\nuse serde::Serialize;\n"})
+    assert _imports(result, "user.rs") == ["command", "file", "io", "serialize"]