It's important to notice that in Neo4j indexes and constraints are two different things.
You can define a composite index that spans multiple properties of the node but you cannot define a constraint that involves multiple properties.
If I remember correctly, the creation of a unique constraint also mean the creation of an index. But not vice versa.

The composite index will be used for queries but you won't see a failure if you try to insert a node with the same label and same properties of an existing one.

I think the only case for which you should create a constraint instead of an index is when @Index(unique=true) is set to true.

But feel free to prove me wrong with test cases (I didn't check this with code).

> I agree that we should warn about the irrelevant index name because in the future the user may switch to another backend that requires explicit name and thus support forward compatibility.

+1