Wrong Type Deduction for Values from Upvalue Tables

[XmiliaH]

If an integer or number array is accessed through an upvalue, the type of the result will be the same as the array, since the handling case in luaK_dischargevars does not set ravi_type as the other case does. The upvalue case it the following: https://github.com/dibyendumajumdar/ravi/blob/170fd797a2be22abae6bd406f35fb50236988551/src/lcode.c#L623-L627

The following lua code will show the issue and crash with ravi/src/lvm.c:2278: luaV_execute: Assertion `(((((rb))->tt_) == (((((5) | ((1) << 4))) | (1 << 15)))) || ((((rb))->tt_) == (((((5) | ((2) << 4))) | (1 << 15)))))' failed.

local function f(x:integer[])
    return function ()
        return x[1][1] + 1
    end
end

local x = f(table.intarray(3))

x()

The bytecode for the inner function contains the unexpected IARRAY_GET, since this object is an integer and not an array.

1       [3]     GETTABUP        0 0 -1  ; x 1
2       [3]     IARRAY_GET      0 0 -1  ; 1
3       [3]     ADDII           0 0 -1  ; - 1
4       [3]     RETURN          0 2
5       [4]     RETURN          0 1

[dibyendumajumdar]

Thank you for the report

[dibyendumajumdar]

Unfortunately the best we can do here is set ANY type as we don't have more specialized opcodes for upvalues.

[XmiliaH]

I don't see a problem with moving https://github.com/dibyendumajumdar/ravi/blob/b0a5b0114230624a58d5aabc923d3128b835bf48/src/lcode.c#L616-L620 out of the if to https://github.com/dibyendumajumdar/ravi/blob/b0a5b0114230624a58d5aabc923d3128b835bf48/src/lcode.c#L630

But I don' know your code better then you.

[dibyendumajumdar]

Stepping in the debugger I see that e has the type of the variable upvalue points to - so you are right that we could infer that the result will be integer in this case. I will need to check this a bit as I wrote this code a while back and I need to refresh my memory.

[dibyendumajumdar]

btw appreciate these reports very much, thank you for taking the time.