Is there a way to add a 'where' clause to a protocol extension?

[nidal-stytch]

I have this type:
public struct Object <Foo: Decodable>

And this extension:
public extension Object where Foo == Bar

That runs though a sorcery script: that starts with:
public extension {{ type.name }} {

How would I add the where clause to the type if it exists which it does not on all types that run through the script?