“Illegal type synonym family application in instance” with functional dependency
“Illegal type synonym family application in instance” with functional dependency
type-families
‘type family’ vs ‘data family’, in brief?
(Boosting useful information from comments into an answer.) Standalone vs In-Class declaration Two syntactically different ways to declare a type family and/or data family, that are semantically equivalent: standalone: type family Foo data family Bar or as part of a typeclass: class C where type Foo data Bar both declare a type family, but inside … Read more
Getting associated type synonyms with template Haskell
It is not implemented because nobody requested it. The odd thing is that TH uses its own AST, which doesn’t follow internal compiler’s AST. As a result, any new feature (e.g. associated type families) is not automatically available via TH. Some one have to open a ticket and implement it. For the reference: internal reifyClass … Read more