Rust: Model impl shadowing

Author: hvitved

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

@@ -74,15 +74,31 @@ abstract class Type extends TType {
 abstract private class StructOrEnumType extends Type {
   abstract ItemNode asItemNode();
 
-  final override Function getMethod(string name) {
+  pragma[nomagic]
+  private Function getMethodCand(ImplOrTraitItemNode impl, string name) {
     result = this.asItemNode().getASuccessor(name) and
-    exists(ImplOrTraitItemNode impl | result = impl.getAnAssocItem() |
+    result = impl.getAnAssocItem() and
+    (
       impl instanceof Trait
       or
       impl.(ImplItemNode).isFullyParametric()
     )
   }
 
+  pragma[nomagic]
+  private Function getImplMethod(ImplOrTraitItemNode impl, string name) {
+    result = this.getMethodCand(impl, name) and
+    impl = any(Impl i | not i.hasTrait())
+  }
+
+  final override Function getMethod(string name) {
+    result = this.getImplMethod(_, name)
+    or
+    // methods from `impl` blocks shadow functions from `impl Trait` blocks
+    result = this.getMethodCand(_, name) and
+    not exists(this.getImplMethod(_, name))
+  }
+
   /** Gets all of the fully parametric `impl` blocks that target this type. */
   final override ImplMention getABaseTypeMention() {
     this.asItemNode() = result.resolveSelfTy() and

rust/ql/test/extractor-tests/canonical_path/CONSISTENCY/PathResolutionConsistency.expected

@@ -1,5 +1,4 @@
 testFailures
-| main.rs:945:26:945:31 | x.m1() | Unexpected result: method=m1 |
 inferType
 | loop/main.rs:7:12:7:15 | SelfParam |  | loop/main.rs:6:1:8:1 | Self [trait T1] |
 | loop/main.rs:11:12:11:15 | SelfParam |  | loop/main.rs:10:1:14:1 | Self [trait T2] |