.YarnProject fails import when inferring variable type as integer via increment

[fmoo]

What is the current behavior?

When implicitly defining a variable through its usage a certain way, the .yarnproject will fail to import and cause various runtime errors. The compile itself fails with a generic error that could also be improved.

Please provide the steps to reproduce, and if possible a minimal demo of the problem:

Create a .yarn file with the following contents:

title: Bug3
---
<<set $akos_talkers = $akos_talkers + 1>>
===

What is the expected behavior?

$akos_talkers should be detected as an integer, and the .yarnproject compiles

Please tell us about your environment:

• Yarn Spinner Version: 2.2
• Unity Version: 2021.3.10f1

Other information

[vlanf]

I think declare should help:

title: Bug3
---
<<declare $akos_talkers = 0 as int>>
<<set $akos_talkers = $akos_talkers + 1>>
===

[McJones]

There are two parts to this bug, the first is that the type inference isn't working correctly. This is fixed in the WIP line groups branch which has a much more rigorous type system. The second is it crashes the import at Unity, this is fixed in https://github.com/YarnSpinnerTool/YarnSpinner-Unity/commit/6d5054b993f9b77cf034885e60fd04eebc6d3225

Closing this now, thanks for finding it.