Equality comparison against a whole @Struct aggregate embeddable throws FeatureNotSupportedException.

Repro (a parameter is the only expressible form; HQL has no struct literal):

  from ItemWithNestedValue where nested = :p

Observed:

  FeatureNotSupportedException: Only the following comparisons are supported: field vs literal, field vs parameter

Required approach: compare per component with $and, for example:

  { $and: [ { "nested.a": { $eq: ... } }, { "nested.b": { $eq: ... } } ] } 

A single sub-document $eq is not viable: MongoDB sub-document equality is field-order sensitive.

Out of scope for HIBERNATE-93 (path expressions into structs).