Rust: Fallback crate resolution

Author: hvitved

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

@@ -208,6 +208,7 @@ 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
@@ -311,6 +312,7 @@ abstract class ItemNode extends Locatable {
   }
 
   /** Gets an _external_ successor named `name`, if any. */
+  pragma[nomagic]
   ItemNode getASuccessor(string name) {
     exists(SuccessorKind kind |
       result = this.getASuccessor(name, kind) and
@@ -629,17 +631,17 @@ abstract class ImplOrTraitItemNode extends ItemNode {
 
 pragma[nomagic]
 private TypeParamItemNode resolveTypeParamPathTypeRepr(PathTypeRepr ptr) {
-  result = resolvePath(ptr.getPath())
+  result = resolvePathImpl(ptr.getPath())
 }
 
 class ImplItemNode extends ImplOrTraitItemNode instanceof Impl {
   Path getSelfPath() { result = super.getSelfTy().(PathTypeRepr).getPath() }
 
   Path getTraitPath() { result = super.getTrait().(PathTypeRepr).getPath() }
 
-  TypeItemNode resolveSelfTy() { result = resolvePath(this.getSelfPath()) }
+  TypeItemNode resolveSelfTy() { result = resolvePathImpl(this.getSelfPath()) }
 
-  TraitItemNode resolveTraitTy() { result = resolvePath(this.getTraitPath()) }
+  TraitItemNode resolveTraitTy() { result = resolvePathImpl(this.getTraitPath()) }
 
   override AssocItemNode getAnAssocItem() { result = this.getADescendant() }
 
@@ -733,7 +735,7 @@ private class ImplTraitTypeReprItemNode extends TypeItemNode instanceof ImplTrai
   }
 
   pragma[nomagic]
-  ItemNode resolveABound() { result = resolvePath(this.getABoundPath()) }
+  ItemNode resolveABound() { result = resolvePathImpl(this.getABoundPath()) }
 
   override string getName() { result = "(impl trait)" }
 
@@ -830,7 +832,7 @@ class TraitItemNode extends ImplOrTraitItemNode, TypeItemNode instanceof Trait {
   Path getABoundPath() { result = super.getATypeBound().getTypeRepr().(PathTypeRepr).getPath() }
 
   pragma[nomagic]
-  ItemNode resolveABound() { result = resolvePath(this.getABoundPath()) }
+  ItemNode resolveABound() { result = resolvePathImpl(this.getABoundPath()) }
 
   override AssocItemNode getAnAssocItem() { result = this.getADescendant() }
 
@@ -882,7 +884,7 @@ class TraitItemNode extends ImplOrTraitItemNode, TypeItemNode instanceof Trait {
 
 class TypeAliasItemNode extends TypeItemNode, AssocItemNode instanceof TypeAlias {
   pragma[nomagic]
-  ItemNode resolveAlias() { result = resolvePath(super.getTypeRepr().(PathTypeRepr).getPath()) }
+  ItemNode resolveAlias() { result = resolvePathImpl(super.getTypeRepr().(PathTypeRepr).getPath()) }
 
   override string getName() { result = TypeAlias.super.getName().getText() }
 
@@ -971,7 +973,7 @@ class TypeParamItemNode extends TypeItemNode instanceof TypeParam {
   Path getABoundPath() { result = super.getATypeBound().getTypeRepr().(PathTypeRepr).getPath() }
 
   pragma[nomagic]
-  ItemNode resolveABound() { result = resolvePath(this.getABoundPath()) }
+  ItemNode resolveABound() { result = resolvePathImpl(this.getABoundPath()) }
 
   /**
    * Holds if this type parameter has a trait bound. Examples:
@@ -1173,6 +1175,11 @@ 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) {
@@ -1194,15 +1201,24 @@ 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
@@ -1326,9 +1342,9 @@ pragma[nomagic]
 private predicate isUnqualifiedSelfPath(RelevantPath path) { path.isUnqualified("Self") }
 
 pragma[nomagic]
-private ItemNode resolvePath0(RelevantPath path, Namespace ns, SuccessorKind kind) {
+private ItemNode resolvePathImpl0(RelevantPath path, Namespace ns) {
   exists(ItemNode res |
-    res = unqualifiedPathLookup(path, ns, kind) and
+    res = unqualifiedPathLookup(path, ns, _) and
     if
       not any(RelevantPath parent).getQualifier() = path and
       isUnqualifiedSelfPath(path) and
@@ -1337,13 +1353,13 @@ private ItemNode resolvePath0(RelevantPath path, Namespace ns, SuccessorKind kin
     else result = res
   )
   or
-  exists(ItemNode q, string name |
-    q = resolvePathQualifier(path, name) and
+  exists(ItemNode q, string name, SuccessorKind kind |
+    q = resolvePathImplQualifier(path, name) and
     result = getASuccessor(q, name, ns, kind) and
     kind.isExternalOrBoth()
   )
   or
-  result = resolveUseTreeListItem(_, _, path, kind) and
+  result = resolveUseTreeListItem(_, _, path, _) and
   ns = result.getNamespace()
 }
 
@@ -1377,19 +1393,21 @@ private predicate pathUsesNamespace(Path p, Namespace n) {
   )
 }
 
-/** Gets the item that `path` resolves to, if any. */
-cached
-ItemNode resolvePath(RelevantPath path) {
+pragma[nomagic]
+private ItemNode resolvePathImpl(RelevantPath path) {
   exists(Namespace ns |
-    result = resolvePath0(path, ns, _) and
+    result = resolvePathImpl0(path, ns) and
     if path = any(ImplItemNode i).getSelfPath()
     then
       result instanceof TypeItemNode and
       not result instanceof TraitItemNode
     else
       if path = any(ImplItemNode i).getTraitPath()
       then result instanceof TraitItemNode
-      else any()
+      else
+        if path = any(PathTypeRepr p).getPath()
+        then result instanceof TypeItemNode
+        else any()
   |
     pathUsesNamespace(path, ns)
     or
@@ -1399,11 +1417,36 @@ ItemNode resolvePath(RelevantPath path) {
 }
 
 pragma[nomagic]
-private ItemNode resolvePathQualifier(RelevantPath path, string name) {
-  result = resolvePath(path.getQualifier()) and
+private ItemNode resolvePathImplQualifier(RelevantPath path, string name) {
+  result = resolvePathImpl(path.getQualifier()) and
   name = path.getText()
 }
 
+/** Gets the item that `path` resolves to, if any. */
+cached
+ItemNode resolvePath(RelevantPath path) {
+  result = resolvePathImpl(path) and
+  // if `path` is the qualifier of a resolvable parent, then we should
+  // resolve `path` to something consistent with what the parent resolves to
+  (
+    not path = any(Path parent | exists(resolvePathImpl(parent))).getQualifier()
+    or
+    exists(ItemNode i, string name |
+      i = resolvePathParent(path, name) and
+      result.getASuccessor(name) = i
+    )
+  )
+}
+
+pragma[nomagic]
+private ItemNode resolvePathParent(RelevantPath path, string name) {
+  exists(RelevantPath parent |
+    result = resolvePath(parent) and
+    path = parent.getQualifier() and
+    name = parent.getText()
+  )
+}
+
 private predicate isUseTreeSubPath(UseTree tree, RelevantPath path) {
   path = tree.getPath()
   or
@@ -1449,7 +1492,7 @@ private ItemNode resolveUseTreeListItemQualifier(
 pragma[nomagic]
 private ItemNode resolveUseTreeListItem(Use use, UseTree tree) {
   tree = use.getUseTree() and
-  result = resolvePath(tree.getPath())
+  result = resolvePathImpl(tree.getPath())
   or
   result = resolveUseTreeListItem(use, tree, tree.getPath(), _)
 }
@@ -1502,21 +1545,13 @@ private predicate externCrateEdge(ExternCrateItemNode ec, string name, CrateItem
 
 pragma[nomagic]
 private predicate preludeItem(string name, ItemNode i) {
-  exists(
-    Crate stdOrCore, string stdOrCoreName, ModuleLikeNode mod, ModuleItemNode prelude,
-    ModuleItemNode rust
-  |
-    stdOrCore.getName() = stdOrCoreName and
-    stdOrCoreName = ["std", "core"] and
+  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"])
-  |
+    rust = prelude.getASuccessor(["rust_2015", "rust_2018", "rust_2021", "rust_2024"]) and
     i = rust.getASuccessor(name) and
     not name = ["super", "self"]
-    or
-    name = stdOrCoreName and
-    i = stdOrCore
   )
 }
 
@@ -1533,7 +1568,7 @@ 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/path-resolution/CONSISTENCY/PathResolutionConsistency.expected

@@ -1,7 +1,3 @@
 multipleCallTargets
 | main.rs:118:9:118:11 | f(...) |
 | proc_macro.rs:9:5:11:5 | ...::new(...) |
-multiplePathResolutions
-| main.rs:641:3:641:12 | proc_macro |
-| main.rs:647:7:647:16 | proc_macro |
-| main.rs:650:7:650:16 | proc_macro |

rust/ql/test/library-tests/path-resolution/path-resolution.expected

@@ -276,14 +276,11 @@ resolvePath
 | main.rs:635:9:635:36 | GenericStruct::<...> | main.rs:578:5:581:5 | struct GenericStruct |
 | main.rs:635:9:635:47 | ...::call_both | main.rs:601:9:604:9 | fn call_both |
 | main.rs:635:25:635:35 | Implementor | main.rs:607:5:607:23 | struct Implementor |
-| main.rs:641:3:641:12 | proc_macro | {EXTERNAL LOCATION} | Crate(proc_macro@0.0.0) |
 | main.rs:641:3:641:12 | proc_macro | proc_macro.rs:0:0:0:0 | Crate(proc_macro@0.0.1) |
 | main.rs:641:3:641:24 | ...::add_suffix | proc_macro.rs:4:1:12:1 | fn add_suffix |
 | main.rs:645:6:645:12 | AStruct | main.rs:644:1:644:17 | struct AStruct |
-| main.rs:647:7:647:16 | proc_macro | {EXTERNAL LOCATION} | Crate(proc_macro@0.0.0) |
 | main.rs:647:7:647:16 | proc_macro | proc_macro.rs:0:0:0:0 | Crate(proc_macro@0.0.1) |
 | main.rs:647:7:647:28 | ...::add_suffix | proc_macro.rs:4:1:12:1 | fn add_suffix |
-| main.rs:650:7:650:16 | proc_macro | {EXTERNAL LOCATION} | Crate(proc_macro@0.0.0) |
 | main.rs:650:7:650:16 | proc_macro | proc_macro.rs:0:0:0:0 | Crate(proc_macro@0.0.1) |
 | main.rs:650:7:650:28 | ...::add_suffix | proc_macro.rs:4:1:12:1 | fn add_suffix |
 | main.rs:655:9:655:11 | std | {EXTERNAL LOCATION} | Crate(std@0.0.0) |