assert len(info.references) == 2 error

[Danewalker]

ljd exit with following error:
Traceback (most recent call last):
File "main.py", line 123, in
retval = main()
File "main.py", line 99, in main
ljd.ast.slotworks.eliminate_temporary(ast)
File "w:\work\ljd\ast\slotworks.py", line 14, in eliminate_tempo
rary
_eliminate_temporary(slots)
File "w:\work\ljd\ast\slotworks.py", line 46, in _eliminate_temp
orary
_fill_massive_refs(info, simple, massive, iterators)
File "w:\work\ljd\ast\slotworks.py", line 68, in _fill_massive_r
efs
assert len(info.references) == 2
AssertionError

Lua source from pbc lua

local lpeg = require "lpeg"
local P = lpeg.P
local V = lpeg.V

local next = next

local proto_tbl = { "PROTO" }

local k, v = next(patterns)
local p = V(k)
proto_tbl[k] = v --- Error

return parser

[jjdredd]

thanks for reporting, please provide branch name and commit number

[Danewalker]

i'm using branch - bugfix with latest commit

[jjdredd]

please, try master

[jjdredd]

@Danewalker do you get the same on master branch?

[tboby]

I have the same issue, and cannot reproduce it on master because of the non-propagation of the stripped flag causing everything to get misaligned. If I cherry-pick Commit 9351dbe then I get the same error.

I've vaguely tried to follow the AST process in debug to see how it happens, but it's a bit much!

[jjdredd]

@ThomasBoby thanks, but that's odd. I don't know why that patch could cause trouble.
If you have interest in source/algo, ask away. I haven't read much of the code but I might be able to help.

[tboby]

@jjdredd
I've managed to find the minimum example where it fails.

local k,v = next(patterns)
local q = V(k)
local p = V(k)

If you comment out the assert it then suceeds, but it doesn't link the k in local k,v with the k in the later instructions.

This seems to be an issue relating to "massive" boxes and having multiple following references to them. You can't get around it by having an intermediate variable either, as it gets optimized out :)