Rust: Fallback crate resolution

Author: hvitved

rust/ql/lib/codeql/rust/internal/PathResolution.qll

@@ -188,6 +188,7 @@ abstract class ItemNode extends Locatable {
     crateDefEdge(this, name, result, kind)
     or
     crateDependencyEdge(this, name, result) and
+    not declaresDirectly(this, TTypeNamespace(), name) and
     kind.isInternal()
     or
     externCrateEdge(this, name, result) and
@@ -1153,6 +1154,11 @@ private class BuiltinSourceFile extends SourceFileItemNode {
 pragma[nomagic]
 private predicate crateDependencyEdge(SourceFileItemNode file, string name, CrateItemNode dep) {
   exists(CrateItemNode c | dep = c.(Crate).getDependency(name) | file = c.getASourceFile())
+  or
+  // All files _should_ belong to a crate, but for those where we cannot identify the crate,
+  // we give access to all crates as a fallback.
+  not file = any(Crate c).getASourceFile() and
+  name = dep.getName()
 }
 
 private predicate useTreeDeclares(UseTree tree, string name) {
@@ -1174,15 +1180,24 @@ private predicate useTreeDeclares(UseTree tree, string name) {
 
 /**
  * Holds if `item` explicitly declares a sub item named `name` in the
- * namespace `ns`. This includes items declared by `use` statements,
- * except for glob imports.
+ * namespace `ns`. This excludes items declared by `use` statements.
  */
 pragma[nomagic]
-private predicate declares(ItemNode item, Namespace ns, string name) {
+private predicate declaresDirectly(ItemNode item, Namespace ns, string name) {
   exists(ItemNode child, SuccessorKind kind | child = getAChildSuccessor(item, name, kind) |
     child.getNamespace() = ns and
     kind.isInternalOrBoth()
   )
+}
+
+/**
+ * Holds if `item` explicitly declares a sub item named `name` in the
+ * namespace `ns`. This includes items declared by `use` statements,
+ * except for glob imports.
+ */
+pragma[nomagic]
+private predicate declares(ItemNode item, Namespace ns, string name) {
+  declaresDirectly(item, ns, name)
   or
   exists(ItemNode child |
     child.getImmediateParent() = item and
@@ -1482,20 +1497,13 @@ private predicate externCrateEdge(ExternCrateItemNode ec, string name, CrateItem
 
 pragma[nomagic]
 private predicate preludeItem(string name, ItemNode i) {
-  exists(Crate stdOrCore, string stdOrCoreName |
-    stdOrCore.getName() = stdOrCoreName and
-    stdOrCoreName = ["std", "core"]
-  |
-    name = stdOrCoreName and
-    i = stdOrCore
-    or
-    exists(ModuleLikeNode mod, ModuleItemNode prelude, ModuleItemNode rust |
-      mod = stdOrCore.getSourceFile() and
-      prelude = mod.getASuccessor("prelude") and
-      rust = prelude.getASuccessor(["rust_2015", "rust_2018", "rust_2021", "rust_2024"]) and
-      i = rust.getASuccessor(name) and
-      not name = ["super", "self"]
-    )
+  exists(Crate stdOrCore, ModuleLikeNode mod, ModuleItemNode prelude, ModuleItemNode rust |
+    stdOrCore.getName() = ["std", "core"] and
+    mod = stdOrCore.getSourceFile() and
+    prelude = mod.getASuccessor("prelude") and
+    rust = prelude.getASuccessor(["rust_2015", "rust_2018", "rust_2021", "rust_2024"]) and
+    i = rust.getASuccessor(name) and
+    not name = ["super", "self"]
   )
 }
 
@@ -1512,7 +1520,7 @@ private predicate preludeItem(string name, ItemNode i) {
 pragma[nomagic]
 private predicate preludeEdge(SourceFile f, string name, ItemNode i) {
   preludeItem(name, i) and
-  not declares(f, _, name)
+  not declares(f, i.getNamespace(), name)
 }
 
 pragma[nomagic]

rust/ql/test/library-tests/variables/CONSISTENCY/PathResolutionConsistency.expected

@@ -1,3 +1,5 @@
 multipleCallTargets
 | main.rs:87:19:87:40 | ...::from(...) |
 | main.rs:106:19:106:40 | ...::from(...) |
+| main.rs:388:5:388:27 | ... .add_assign(...) |
+| main.rs:473:9:473:23 | z.add_assign(...) |