Identical to, or derived from true_type if two allocators of parameterized ALLOCATOR_TYPE always compare equal; otherwise identical to or derived from false_type. This type is ALLOCATOR_TYPE::is_always_equal if such a type is defined, and is_empty<ALLOCATOR_TYPE> otherwise.
Declared in <bslma_allocatortraits.h>
typedef BloombergLP::bslma::AllocatorTraits_IsAlwaysEqual<ALLOCATOR_TYPE>::type is_always_equal;