Type families error that I don't understand

bonkers.hs

{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE TypeFamilies #-}

class Bonkers b where
 type Bonkers1 b   :: *
 type Bonkers2 b   :: *

 bonkersFrom :: Bonkers1 b -> Bonkers2 b

bonkers' :: Bonkers b => Bonkers1 b -> Bonkers2 b
bonkers' = bonkersFrom

--- Error ---

bonkers.hs:10:13:
    Could not deduce (Bonkers2 b0 ~ Bonkers2 b)
    from the context (Bonkers b)
      bound by the type signature for
                 bonkers' :: Bonkers b => Bonkers1 b -> Bonkers2 b
      at src/Umami/Test.hs:10:13-49
    NB: ‘Bonkers2’ is a type function, and may not be injective
    The type variable ‘b0’ is ambiguous
    Expected type: Bonkers1 b -> Bonkers2 b
      Actual type: Bonkers1 b0 -> Bonkers2 b0
    In the ambiguity check for:
      forall b. Bonkers b => Bonkers1 b -> Bonkers2 b
    To defer the ambiguity check to use sites, enable AllowAmbiguousTypes
    In the type signature for ‘bonkers'’:
      bonkers' :: Bonkers b => Bonkers1 b -> Bonkers2 b




--- Without type signature ---

{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE TypeFamilies #-}

class Bonkers b where
 type Bonkers1 b   :: *
 type Bonkers2 b   :: *

 bonkersFrom :: Bonkers1 b -> Bonkers2 b

bonkers' = bonkersFrom

--- Error ---

bonkers.hs:10:12:
    No instance for (Bonkers b0) arising from a use of ‘bonkersFrom’
    In the expression: bonkersFrom
    In an equation for ‘bonkers'’: bonkers' = bonkersFrom