Type Functions aren't designed for AssignPropConstraint?

[karl-police]

Somewhere I wanted to experiment with table types. https://github.com/karl-police/luau/blob/ca4f440b3818331293158c5d55f7ece98b98c4fa/Analysis/src/TypeFunction.cpp#L2359

While I am not sure if I've ever done this right. I'd run into an issue.

If I mixed this with keyof here's a few things that would happen.

 

Let's assume this would be my Luau code put into a Unit Test.

local tbl_C = nil :: tabletype<"unsealed">
tbl_C.entry3 = "abc"

type indexesABC = keyof<typeof(tbl_C)>

Apparently this is what happens step by step:

1. tbl_C gets created
2. tbl_C.entry3 = "abc" triggered, the tryDispatch function from ConstraintSolver.cpp
3. We trigger AssignPropConstraint
4. TypeId lhsType = follow(c.lhsType); this happens
5. lhsType is going to be a TypeFunctionInstanceType
6. tryDispatch will fail and return false, because it is blocked
7. keyof gets triggered, but it won't have any keys
8. The checking proceeds
9. Later somehow it re-triggers AssignPropConstraint
10. entry3 gets added into that table
11. Not sure why it didn't do it before.

And what I don't understand is, if this is my fault or if this is something that yet has to be refined in Luau.