Thanks for the posts about this issue.
To workaround this issue you need to define your respective @editable variables with a default value
This will workaround the issue:
test_class := class:
hello_world_device := class(creative_device):
@editable MyMesh : mesh = Meshes.Box_D2757564
@editable TestClass : test_class = test_class {}
This will continue to crash the Verse Language Server:
test_class := class:
hello_world_device := class(creative_device):
@editable MyMesh : mesh
@editable TestClass : test_class