[yw3410]

Monads have nothing to do with laziness and we're talking about the Result type anyway.

OP is correct. If it has a bind, pure and map (which it does!) then for all intents it forms a monad.

Now the fact is you can't _manipulate_ monads in Rust easily (see kinds and discussions wrt GAT), but nonetheless monads are present in all languages with ADTs in the same way that rings are present in all languages with addition.