pub trait StructuralPartialEq { }structural_match)Expand description
Required trait for constants used in pattern matches.
Any type that derives PartialEq automatically implements this trait,
regardless of whether its type-parameters implement PartialEq.
If a const item contains some type that does not implement this trait,
then that type either (1.) does not implement PartialEq (which means the
constant will not provide that comparison method, which code generation
assumes is available), or (2.) it implements its own version of
PartialEq (which we assume does not conform to a structural-equality
comparison).
In either of the two scenarios above, we reject usage of such a constant in a pattern match.
See also the structural match RFC, and issue 63438 which motivated migrating from an attribute-based design to this trait.