@jakehamilton The preference should always be to define a specific type that matches what the module expects. types.anything’s main purpose is to be a “safe” fallback when it’s unclear what the type should be, with behavior that’s as generic (accepting all values) and predictable (having expected merge results) as possible. I intended for types.anything to eventually replace types.unspecified (which has terrible merge behavior!) as the default option type.
The problem with listOf anything’s merging behavior is that it merges by concatenating values in somewhat non-deterministic order (it depends on imports order), which can cause problems when the order is important (and it has before!). Furthermore, merging by concatenation can break stuff, such as when lists should have a fixed length (e.g. a transformation Matrix), or if the list represents one “thing” by itself (e.g. interpolation points for a gradient). That’s why it’s not fit as a safe default for types.anything, even though it would work in most cases.