Using TweenSequence<FooBar> results in "type _$FooBarImpl might not fully implement..."

[jimmyff]

Hey firstly thanks for this awesome package, it's really great!

The issue I've found is that I'm trying to use TweenSequnce<FooBar> where FooBar is my @freezed class however this gives the following error:

The type _$FooBarImpl might not fully implement +, -, and/or *. See "Types with special considerations"

I've implemented a static lerp method which would normally work however this is on FooBar and not _$FooBarImpl

Any advice on how I might fix would be really appreciated,

Thanks

[rrousselGit]

An example would be great. I can't reproduce it as is