fix(rust): a module path names the module's free function, not a method

CHANGELOG.md

@@ -14,6 +14,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### Fixes
 
+- In Rust, a call written through a module path, like `crate::util::take(…)`, `super::util::take(…)` or `util::take(…)`, now links to the free function that module declares, and a `use crate::util::take;` now links to it too. Before, a same-named method in an `impl` block above the function, or a function nested inside another one in that file, took the call, and the `use` often linked to nothing.
 - A Python module member used through the imported module, like `generic.ObjectEditView` after `from netbox.views import generic`, `serializers.ValidationError` or `utils.assert_deserialize(…)`, now also follows the package's re-exports to its definition. Before, netbox's view classes lost their `generic.*` base classes, and mealie's test helpers called through `utils.` went unresolved.
 - A Python name imported from a package now follows the package's re-exports to where it's defined. That covers both `from .users import *` and `from .tokens import Token` in its `__init__.py`. Before, httpx's own tests' `httpx.Client(…)` and `httpx.URL(…)`, pytest's `pytest.raises(…)` and `pytest.param(…)`, and netbox's `from users.models import User` went unresolved or to a same-named class elsewhere, such as a test's `User` or an Alembic migration's copy of a model.
 - In NestJS projects, the provider naming convention (`…Service`, `…Controller`, …) now picks a class only from the reference's own file. Another file's provider is reached through its import, or by ordinary name matching that prefers the nearest declaration. Before, the convention's preference for `*.service.ts` files sent Nest's own specs' `TransientService` and `TestService` to same-named classes in unrelated sample apps.

__tests__/rust-module-path-call.test.ts

@@ -0,0 +1,147 @@
+/**
+ * A Rust call written through a module path — `crate::util::take(3)`,
+ * `super::util::take(3)`, `self::util::take(3)`, `util::take(3)` after
+ * `use crate::util;` — is the free function that module declares, and so is
+ * a `use crate::util::take;`. A path never names a method (that takes
+ * `Type::method`), nor a function local to another function's body, even when
+ * the module's file declares one of the same name above the free function.
+ */
+import { describe, it, expect, afterAll, beforeAll } from 'vitest';
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import { CodeGraph } from '../src';
+
+let root = '';
+let cg: CodeGraph;
+
+beforeAll(async () => {
+  root = fs.mkdtempSync(path.join(os.tmpdir(), 'cg-rust-module-path-'));
+  const files: Record<string, string> = {
+    'Cargo.toml': '[package]\nname = "app"\nversion = "0.1.0"\n',
+    'src/lib.rs': `mod util;
+mod only;
+mod a;
+mod caller;
+mod importer;
+
+pub fn via_self() -> usize {
+    self::util::take(1)
+}
+`,
+    'src/util.rs': `pub struct Buf;
+
+impl Buf {
+    pub fn take(&self, n: usize) -> usize {
+        n
+    }
+}
+
+pub trait Take {
+    fn take(&self) -> usize;
+}
+
+fn outer() -> usize {
+    fn take() -> usize {
+        0
+    }
+    take()
+}
+
+pub fn take(n: usize) -> usize {
+    n
+}
+`,
+    'src/only.rs': `pub struct Only;
+
+impl Only {
+    pub fn grab(&self) -> usize {
+        0
+    }
+}
+`,
+    'src/a/mod.rs': 'pub mod b;\n',
+    'src/a/b.rs': `pub struct Deep;
+
+impl Deep {
+    pub fn get(&self) -> usize {
+        0
+    }
+}
+
+pub fn get() -> usize {
+    1
+}
+`,
+    'src/importer.rs': 'use crate::util::take;\n',
+    'src/caller.rs': `use crate::util;
+
+pub fn via_crate() -> usize {
+    crate::util::take(1)
+}
+
+pub fn via_super() -> usize {
+    super::util::take(1)
+}
+
+pub fn via_module() -> usize {
+    util::take(1)
+}
+
+pub fn via_nested() -> usize {
+    crate::a::b::get()
+}
+
+pub fn via_method_only() -> usize {
+    crate::only::grab()
+}
+
+pub fn via_missing() -> usize {
+    crate::nowhere::take(1)
+}
+`,
+  };
+  for (const [rel, content] of Object.entries(files)) {
+    fs.mkdirSync(path.dirname(path.join(root, rel)), { recursive: true });
+    fs.writeFileSync(path.join(root, rel), content);
+  }
+  cg = await CodeGraph.init(root, { index: true });
+});
+
+afterAll(() => {
+  cg?.close();
+  if (root) fs.rmSync(root, { recursive: true, force: true });
+});
+
+/** What the function `name` in `file` calls, as `kind qualifiedName file:line`. */
+const callsFrom = (file: string, name: string): string[] => {
+  const fn = cg.getNodesInFile(file).find((n) => n.name === name)!;
+  return cg.getOutgoingEdgesFrom([fn.id]).filter((e) => e.kind === 'calls')
+    .map((e) => cg.getNode(e.target)!).map((t) => `${t.kind} ${t.qualifiedName} ${t.filePath}:${t.startLine}`);
+};
+
+describe('Rust calls through a module path', () => {
+  it('reach the free function the module declares, never a same-named method or local fn', () => {
+    const take = 'function take src/util.rs:20';
+    expect(callsFrom('src/caller.rs', 'via_crate')).toEqual([take]);
+    expect(callsFrom('src/caller.rs', 'via_super')).toEqual([take]);
+    expect(callsFrom('src/caller.rs', 'via_module')).toEqual([take]);
+    expect(callsFrom('src/lib.rs', 'via_self')).toEqual([take]);
+  });
+
+  it('bind a use of the function to it', () => {
+    const ids = cg.getNodesInFile('src/importer.rs').map((n) => n.id);
+    const targets = cg.getOutgoingEdgesFrom(ids).filter((e) => e.kind === 'imports')
+      .map((e) => cg.getNode(e.target)!).map((t) => `${t.kind} ${t.qualifiedName} ${t.filePath}:${t.startLine}`);
+    expect(targets).toEqual(['function take src/util.rs:20']);
+  });
+
+  it('walk a nested module path to its file', () => {
+    expect(callsFrom('src/caller.rs', 'via_nested')).toEqual(['function get src/a/b.rs:9']);
+  });
+
+  it('link nothing when the module declares no such free function, or is not in the index', () => {
+    expect(callsFrom('src/caller.rs', 'via_method_only')).toEqual([]);
+    expect(callsFrom('src/caller.rs', 'via_missing')).toEqual([]);
+  });
+});

src/resolution/import-resolver.ts

@@ -17,6 +17,7 @@ import {
   resolveObjectLiteralBinding,
   localReceiverTypePatterns,
   normalizeInferredTypeName,
+  isLexicallyReachable,
 } from './name-matcher';
 
 /**
@@ -2186,6 +2187,10 @@ function resolveRustPathReference(
   const file = resolveRustModuleFile(modSegs, ref.filePath, context);
   if (!file || file === ref.filePath) return null;
 
+  // The module's own item. A path never names a method (that is
+  // `Type::method`), nor a fn local to another fn's body: the file's first
+  // same-named node was taken, so an `impl Buf { fn take }` above
+  // `pub fn take` caught every `crate::util::take(…)`.
   const target = context.getNodesInFile(file).find(
     (n) =>
       n.name === leaf &&
@@ -2196,9 +2201,9 @@ function resolveRustPathReference(
         n.kind === 'trait' ||
         n.kind === 'type_alias' ||
         n.kind === 'constant' ||
-        n.kind === 'method' ||
         n.kind === 'class' ||
-        n.kind === 'interface')
+        n.kind === 'interface') &&
+      isLexicallyReachable(n, ref, context)
   );
   if (target) {
     return { original: ref, targetNodeId: target.id, confidence: 0.9, resolvedBy: 'import' };