diff --git a/primer/src/Primer/TypeDef.hs b/primer/src/Primer/TypeDef.hs
index 00d9c2cec..ecdcf6950 100644
--- a/primer/src/Primer/TypeDef.hs
+++ b/primer/src/Primer/TypeDef.hs
@@ -1,5 +1,3 @@
-{-# LANGUAGE OverloadedLabels #-}
-
 module Primer.TypeDef (
   TypeDef (..),
   ValCon (..),
@@ -19,7 +17,9 @@ import Foreword
 
 import Control.Monad.Fresh (MonadFresh)
 import Data.Data (Data)
-import Optics (Field2 (_2), mapped, over, traverseOf, traversed, (%))
+import Data.Generics.Product (HasParam (param), Param (StarParam))
+import Optics (set, traverseOf)
+import Primer.Core.DSL.Meta (kmeta, meta)
 import Primer.Core.Meta (
   ID,
   TyConName,
@@ -33,7 +33,7 @@ import Primer.Core.Type (
   Type' (TForall, TFun, TVar),
   TypeMeta,
  )
-import Primer.Core.Utils (forgetKindMetadata, forgetTypeMetadata, generateKindIDs, generateTypeIDs)
+import Primer.Core.Utils (forgetTypeMetadata)
 import Primer.JSON (
   CustomJSON (CustomJSON),
   FromJSON,
@@ -105,24 +105,12 @@ typeDefAST = \case
 typeDefKind :: TypeDef b () -> Kind' ()
 typeDefKind = foldr (KFun () . snd) (KType ()) . typeDefParameters
 
--- TODO/REVIEW: I cannot see how to do this nice and lens-y (see old code
--- above) because we cannot change metadata in params indep to in ctors,
--- as both controlled by same `c`
 forgetTypeDefMetadata :: TypeDef b c -> TypeDef () ()
-forgetTypeDefMetadata (TypeDefPrim td) = TypeDefPrim $ over (#primTypeDefParameters % mapped % _2) forgetKindMetadata td
-forgetTypeDefMetadata (TypeDefAST (ASTTypeDef ps cs hs)) =
-  TypeDefAST $
-    ASTTypeDef
-      (over (mapped % _2) forgetKindMetadata ps)
-      (over (mapped % #valConArgs % mapped) forgetTypeMetadata cs)
-      hs
+forgetTypeDefMetadata =
+  set (param @1) ()
+    . set (param @0) ()
 
 generateTypeDefIDs :: MonadFresh ID m => TypeDef () () -> m (TypeDef TypeMeta KindMeta)
-generateTypeDefIDs (TypeDefPrim td) = TypeDefPrim <$> traverseOf (#primTypeDefParameters % traversed % _2) generateKindIDs td
-generateTypeDefIDs (TypeDefAST (ASTTypeDef ps cs hs)) =
-  TypeDefAST
-    <$> liftA3
-      ASTTypeDef
-      (traverseOf (traversed % _2) generateKindIDs ps)
-      (traverseOf (traversed % #valConArgs % traversed) generateTypeIDs cs)
-      (pure hs)
+generateTypeDefIDs =
+  traverseOf (param @1) (\() -> meta)
+    <=< traverseOf (param @0) (\() -> kmeta)