Declared in <bits/memory_resource.h>
[[nodiscard]]
bool
operator==(
polymorphic_allocator<BslAllocator_Voidish> const& __a,
polymorphic_allocator<BslAllocator_Voidish> const& __b) noexcept;
This function is a hidden friend of allocator<void>, declared inside its base class polymorphic_allocator: it can be found only through argument-dependent lookup.
The return value should not be discarded.