ladybird/Tests/ClangPlugins/LibJSGCTests/substruct_with_value.cpp
Andreas Kling 95b464fb8b ClangPlugins: Check for GC pointers in non-Cell substruct members
This extends the LibJSGC Clang plugin to detect GC pointers (GC::Ptr,
GC::Ref, JS::Value, etc.) inside non-GC-allocated struct/class members.

When a GC::Cell has a member of a non-Cell type that contains GC
pointers, we now enforce that:

1. The non-Cell type must have a visit_edges(GC::Cell::Visitor&) method
2. The Cell's visit_edges must access that member (presumably to call
   its visit_edges)

The check works recursively, so nested structs and containers like
Vector<GC::Ptr<T>> or HashMap<K, GC::Ptr<V>> are handled correctly.

GC infrastructure types (Root, Heap, etc.) and AK library types are
excluded from these checks as they handle visitation differently.
2026-01-07 12:48:58 +01:00

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/*
* Copyright (c) 2026, Andreas Kling <andreas@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
// RUN: %clang++ -Xclang -verify %plugin_opts% -c %s -o %t 2>&1
#include <LibJS/Runtime/Object.h>
// A substruct that contains a JS::Value but has no visit_edges method
// (fine on stack, but not as a Cell member)
struct SubStructWithValue {
JS::Value m_value;
};
class TestClass : public JS::Object {
JS_OBJECT(TestClass, JS::Object);
virtual void visit_edges(Visitor& visitor) override
{
Base::visit_edges(visitor);
}
// expected-error@+1 {{Member m_substruct contains GC pointers but its type has no visit_edges method}}
SubStructWithValue m_substruct;
};