Type complexity + LuauTarjanChildLimit causes *error-type* for resolved requires

[ghost]

local module = require(script:FindFirstChild("module"))

local module = {}

function module.execute(player: Player) end -- Won't occur with `player: Instance`.

return module

While I can jump to the module from the require line, module gets typed to *error-type*. This does not occur with "Fflags Enable By Default" off. I don't think this occurred five days ago.

I haven't yet been able to replicate this in a new project.

[JohnnyMorganz]

Strange..., I can reproduce this in my project, but not in a new project as well.

[JohnnyMorganz]

Few things I can uncover from this:

• Setting FFlag LuauTarjanChildLimit to 0 fixes this.
• Because we are using the autocomplete typechecker, we are subject to the dynamic limits set on the autocomplete (so that it resolves in a reasonable amount of time). Alternatively, setting LuauAutocompleteDynamicLimits to False can fix this (probably also why "fflags enable by default" causes this)
• If you don't want to use the autocomplete typechecker to provide hover information, you can disable luau-lsp.hover.strictDatamodelTypes. The side effect of disabling this means the limits are no longer used, so this should resolve correctly
• The error depends on the complexity of the types and complexity of the project the module is present in

[JohnnyMorganz]

The issue also occurs for external packages, e.g. https://wally.run/package/vorlias/net

[JohnnyMorganz]

From discord: It seems the issue is tied to the size of the sourcemap.
It is most likely our "makeLazyInstanceType" is expensive

[JohnnyMorganz]

I've manually enforced a lower bound of 15,000 on LuauTarjanChildLimit to help alleviate some issues.