AST Returns Invalid JSON for Generic Packs

[Wingysam]

I'm running into an issue with a case like this:

a = function<b..., c...>()
end

The AST looks like this:

root@4cc223a530e7:/app# luau-ast test.lua  | rg '\[,\]'

{"root":{"type":"AstStatBlock","location":"0,0 - 2,0","hasEnd":true,"body":[{"type":"AstStatAssign","location":"0,0 - 1,3","vars":[{"type":"AstExprGlobal","location":"0,0 - 0,1","global":"a"}],"values":[{"type":"AstExprFunction","location":"0,4 - 1,3","attributes":[],"generics":[],"genericPacks":[,],"args":[],"vararg":false,"varargLocation":"0,0 - 0,0","body":{"type":"AstStatBlock","location":"0,26 - 1,0","hasEnd":true,"body":[]},"functionDepth":1,"debugname":""}]}]},"commentLocations":[]}

The problem is the empty array with a comma in it:

"genericPacks":[,]

I suspect there is meant to be data here that gets serialized to empty string rather than valid JSON.

Tested with a build from a2303a6.

[JohnnyMorganz]

This was fixed in 672 #1800

[vegorov-rbx]

@JohnnyMorganz thank you for noting the fix!