Using multiple inheritance in root gives much prettier output about datatype-expansion HOT 2 CLOSED

Hi @postatum, thanks for reporting this!

It is an actual bug. If there's a union type in any node, the canonical form should push it to the top level node, computing all possible variations in the union.
The intention is that with the canonical form you don't need to deal with inheritance or unions, just go through a list of flat (because inheritance has also been computed) trees.

For some use cases, the symmetric transformation might be more useful: pushing the union type inside the tree as much as possible, compacting a union of trees at the top node into a single tree, with multiple union nodes inside, but we don't have an implementation or a definition of such a 'compact' transformation yet.

For this particular error, it looks like is missing an additional invocation to the canonical function after computing the inheritance, I'll take a look at it ASAP.

from datatype-expansion.

@antoniogarrote thanks for response. It makes sense now :)

from datatype-expansion.