__index behavior broke for mixed metatables

[Tomarty]

Started getting some new errors this morning in studio. Here’s a simple repro:

local mt = {
	{}, -- This field causes the issue.
	__index = {X = true},
}
local self = setmetatable({}, mt)
assert(self.X) -- fails

I was using the array part to create a 2-dimensional weak table cache. I can fix it easily by using the array’s hash part instead. I usually use the array part of tables to optimize memory usage and reduce unique string constants. It worked yesterday night, so it seems like an unintentional VM behavior change.

[zeuxcg]

@Tomarty

local mt = {
	{}, -- This field causes the issue.
	__index = {X = true},
}
local self = setmetatable({}, mt)
assert(self.X) -- fails

Should be fixed now, thanks for the report.