Merge pull request #21297 from hvitved/rust/type-inference-fix-bug

Rust: Fix bug in `inferMethodCallTypeSelf`

Author: paldepind

rust/ql/lib/codeql/rust/internal/typeinference/DerefChain.qll

@@ -20,13 +20,12 @@ class DerefImplItemNode extends ImplItemNode {
   Type resolveSelfTypeAt(TypePath path) { result = resolveImplSelfTypeAt(this, path) }
 
   /**
-   * Holds if the target type of the dereference implemention mentions a type
-   * parameter at `path`.
+   * Holds if the target type of the dereference implementation mentions type
+   * parameter `tp` at `path`.
    */
   pragma[nomagic]
-  predicate targetHasTypeParameterAt(TypePath path) {
-    this.getAssocItem("Target").(TypeAlias).getTypeRepr().(TypeMention).getTypeAt(path) instanceof
-      TypeParameter
+  predicate targetHasTypeParameterAt(TypePath path, TypeParameter tp) {
+    tp = this.getAssocItem("Target").(TypeAlias).getTypeRepr().(TypeMention).getTypeAt(path)
   }
 
   /** Gets the first type parameter of the type being implemented, if any. */

rust/ql/lib/codeql/rust/internal/typeinference/TypeInference.qll

@@ -2642,7 +2642,7 @@ private Type inferMethodCallTypeSelf(
     not result instanceof TypeParameter
     or
     exists(TypePath pathToTypeParam, TypePath suffix |
-      impl.targetHasTypeParameterAt(pathToTypeParam) and
+      impl.targetHasTypeParameterAt(pathToTypeParam, selfParamType) and
       path0 = pathToTypeParam.appendInverse(suffix) and
       result = t0 and
       path = selfPath.append(suffix)