SSOHashMapOrSet.hasValue

In the hash map case, V is non-void, and a value is stored alongside the key of type K.

struct SSOHashMapOrSet(K, V = void, alias Allocator = null, alias hasher = hashOf, uint smallBinMinCapacity = 1, uint growScaleP = 3, uint growScaleQ = 2)
enum hasValue = !is(V == void);

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