Prevent identifiers being qualified to themselves (#56091)

Summary:
Pull Request resolved: #56091

Changelog: [Internal]

When qualifying a member, prevent taking itself as a target for qualification, to prevent types referencing themselves.

Reviewed By: cipolleschi

Differential Revision: D96455842

fbshipit-source-id: 2ed59a4688d0daa98db603a734283f41ffbe4ead

Author: coado

scripts/cxx-api/parser/scope/scope.py

@@ -26,6 +26,7 @@ def __init__(self, kind: ScopeKindT, name: str | None = None) -> None:
         self.location: str | None = None
         self._members: list[Member] = []
         self._private_typedefs: dict[str, TypedefMember] = {}
+        self._qualifying_member: Member | None = None
 
     def get_qualified_name(self) -> str:
         """
@@ -85,6 +86,8 @@ def qualify_name(self, name: str | None) -> str | None:
 
             # Check if it's a member (type alias, variable, etc.)
             for m in current_scope._members:
+                if m is current_scope._qualifying_member:
+                    continue
                 if m.name == base_first and not isinstance(m, FriendMember):
                     prefix = current_scope.get_qualified_name()
                     return f"{prefix}::{name}" if prefix else name
@@ -110,7 +113,9 @@ def qualify_name(self, name: str | None) -> str | None:
                 matched_segments.append(path_segment)
                 current_scope = current_scope.inner_scopes[base_name]
             elif any(
-                m.name == base_name and not isinstance(m, FriendMember)
+                m.name == base_name
+                and not isinstance(m, FriendMember)
+                and m is not current_scope._qualifying_member
                 for m in current_scope._members
             ) or any(
                 any(m.name == base_name for m in inner._members)
@@ -194,7 +199,9 @@ def close(self) -> None:
             typedef.close(self)
 
         for member in self.get_members():
+            self._qualifying_member = member
             member.close(self)
+        self._qualifying_member = None
 
         self.kind.close(self)
 

scripts/cxx-api/tests/snapshots/should_not_self_qualify_using_typedef/snapshot.api

@@ -0,0 +1,7 @@
+struct test::Container {
+  public using Wrapper = test::Wrapper<int>;
+}
+
+template <typename T>
+struct test::Wrapper {
+}

scripts/cxx-api/tests/snapshots/should_not_self_qualify_using_typedef/test.h

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+namespace test {
+
+template <typename T>
+struct Wrapper {};
+
+struct Container {
+  using Wrapper = Wrapper<int>;
+};
+
+} // namespace test